b'v^ \n\nx^ .\' \n\n\n\n\n\n\n\n\n\n\n\n\ni:^ 9<> \n\n\n\n\n\n\n\n\n\nv^ \n\n\n\n\n\n\n\n- .^-i <?. \n\n\n\n/ \xc2\xb0- \n\n\n\n\n\n\n\n\n\n\n\n\nx..^ \n\n\n\n\n\n\n\n\n\n.9 \'^<^ \n\n\n\n\n\n\n\n\n\n\n- ^ ^ ^ ff Si \xc2\xbb- \'f^ \n\n\n\n\n\n\n\n\n\n\n\n\n\n\nK^ ^- \n\n\n\n\n\n\n\n\n\n\n\n\n^^r- % 0^ \n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\ncS A. \n\n\n\n\n\n\n\n\n\n\n\n\n\n< \n\n\n\n.^^ \n\n\n\n\n\n\n:!^ ^ \n\n\n\n.^ \n\n\n\no:^ ^ \n\n\n\n\n\n\n\n\n\n\n\n\n% \n\n\n\n\n\n\n\n\n\n\n\n\n.^ \n\n\n\n\n\n\n\n\n\n^O. ^ \xe2\x96\xa0\' \xc2\xbb 4 s \n\n\n\n\nr^-s: \n\n\n\n"^-. ,^^ \n\n\n\n"^-..^^ \n\n\n\n\n\n\nV \xc2\xbb \n\n\n\n.<d 0<^ "- \xc2\xbbi \n\n\n\nELEMENTS \n\n\n\nOF \n\n\n\nIN \nA COURSE OF LECTURES \n\nBY \n\nF. R. S. L. ^- E. V. P. R. 1. \n\nMEMBER OF THE BOARS OF AGRICULTURE, OF THE ROYAE IRISH ACADEMY, OF THE \nACADEMIES OF ST. PETERSBURKH, STOCKHOLM, BERLIN, PHILADELPHIA, &\xe2\x82\xac., AJIII \nHONORART PROFESSOR OF CHEMISTRY TO THE ROYAL INSTITUTIOX. \n\n\n\nTO WHICH IS ADDED, \n\nA TREATISE ON SOILS AND MANURES, \n\nAS \n\nt \n\nFOUNDED ON ACTUAL EXPERIENCE, \n\nAND \n\nAS COMBINED WITH THE LEADING PRINCIPLES \n\nIN WHICH THE \n\nijHEORY AND DOCTRINES OF SIR HUMPHRY DAVY, \n\nAND OTHER AGRICULTURAL CHEMISTS, \n\nkUB RENDERED FAMILIAR TO THE EXPERIENCED FARMER. \n\nBY A PRACTICAL AGRICULTURIST. \n\n\n\nPHILADELPHIA: \n\nPUBLISHED BY B. WARNER, M. CAUEY &C SON, AND BENNETT & WALTON: \n\nAND IN BALTIMORE, \n\nBY F. LUCAS .TR., JOSEPH CUSHING, AND EDWARD .1. COALE. \n\n1821 \n\n\n\n\n\n\ntiiiggs & Dickkuon\xe2\x80\x94 PviWei-s. \n\n\n\n\n\n\n\n\n\nir^E^ll^EKT aXD 2VIE3^15E11S \n\n\n\nTHE BOARD OF AGRICULTURE \n\n\n\nFOR THE YEAR 1812, \n\n\n\n\xe2\x80\xa2JPllia^\xc2\xae SLI3(0^IiIBS\xc2\xa93 \n\n\n\nPUBLISHED AT THEIR REQUEST, \n\n\n\nARE IXSCRIBEI) AS A \n\n\n\nTESTIMONY OF THE RESPECT OF THE AUTHOR, \n\n\n\nHIS GRATITUDE FOR THE ATTENTION WITH WHICH \nTHEY HAVE BEEN RECEIVED. \n\n\n\nV- \n\n\n\nAIDTSIB^Il^SllSa^i \n\n\n\nDuring ten years, since 1802, I have had the honour? \nevery Session, of delivering Courses of Lectures before the \nBoard of Agriculture. I have endeavoured, at all times, to \nfollow in them the progress of chemical discovery ; they have \ntherefore varied every year : and such is the rapidity with \nwhich Chemistry is extending, that some alterations and im- \nprovements were rendered necessary at the time they were \npreparing for the press. \n\nThe Duke of Bedford has enabled me to stamp a value \nupon this Work, by permitting me to add to it the results of \nthe experiments instituted by His Grace upon the quantity \nof produce afforded by the different grasses. \n\nI am indebted for much useful information to many mem- \nbers of the Board ; of which acknowledgements will be \nfound in the body of the Work. If there are any omis- \nsions on this head, I trust they will be attributed to defect of \nrecollection, and not to any want of candour or of gra- \ntitude. \n\nWhere I have derived any specific statements from books, \nI have always quoted the authors ; but I have not always \nmade references to such doctrines as are become current, the \nauthors of which are well known ; and which may be almost \nconsidered as the property of all enlightened minds. \n\nAmongst books to whicii I have not referred for any par- \nticular facts, but which contain much useful general informa- \ntion, I shall mention the Earl of Dundonald\'s Treatise on \n\n\n\nVI ADVERTISEMENT. \n\nthe Connprtion of Chemistry wicii Agriculture ; Dr. Rennie\'s \nDissertations on Peat ; and the General Report of the Agri- \nculture of Scotland. This last work did not come into my \nhands till the concluding sheets of these Lectures were print-\' \ning Had it been in circulation before, I should have profit- \ned by many statements given in it, particularly those of the \nopinions of the enlightened Professor of Agriculture in the \nUniversity of Edinburgh : and I should have dwelt with \nsarisfaction on the importance given to some chemical doc- \ntrines by his experience. \n\nBerkeley Square, March 21, 1813. \n\n\n\n\xc2\xa9DS^ISS^^g; \n\n\n\nLECTURE I. \n\nPage \nINTRODUCTION. Generar Views of the Objects of the \nCourse, and of the Order in which they are to be discussed, 9 \n\nLECTURE II. \n\nOf the general Powers of Matter which influence Vegetation ; \nof Gravitation, of Cohesion, of Chemical Attraction, of Heat, \nof Light, of Electricity, ponderable Substances, Elements of \nMatter, particularly those found in Vegetables, Laws of their \nCombinations and Arrangements, ----- 27 \n\nLECTURE III. \n\nOn the Organization of Plants. Of the Roots, Trunk, and \nBranches ; of their Structure. Of the Epidermis. Of the \ncortical and alburnous Parts of Leaves, Flowers and Seeds. \nOf the chemical Constitution of the Organs of Plants, and the \nSubstances found in them. Of mucilaginous, saccharine, \nextractive, resinous, and oily Substances, and other vegetable \nCompounds, their Arrangements in the Organs of Plants, \ntheir Composition, Changes, and Uses, - - . - - 43 \n\nLECTURE IV. \n\nOn Soils ; their constituent Parts. On the Analysis of Soils. \nOf the Uses of the Soil. Of the Rocks and Strata found \nbeneath Soils. Of the Improvement of Soils, - - 109 \n\nLECTURE V. \n\nOn the Nature and Constitution of the Atmosphere, and its In- \nfluence on Vegetables. Of the Germination of Seeds. Of \nthe Functions of Plants in their different Stages of Growth ; \nwith a general View of the Progress of Vegetation, - 143 \n\n\n\nVlll CONTENTS. \n\nLECTURE VI. \n\nPage \nOf Manures of vegetable and animal Origin. Of the Manner \nin which they become the Nourishment of the Plant. Of \nFermentation and Putrefaction. Of the different Species of \nManures of Vegetable origin ; of the different Species of \nanimal Origin. Of mixed Manures, General Principles \nwith respect to the Use and Application of such Manures 184 \n\nLECTURE VIL \n\nOf Manures of Mineral Origin, or fossile Manures ; their Pre- \nparation, and the Manner in which thfcy act. Of Lirne in its \ndifferent States ; Operatioii of Lime as a Manure and a Ce- \nment ; different Combinations of Lime. Of Gypsum ; Ideas \nrespecting its Use. Of other Neutro-saline Compounds, \nemployed as Manures. Of Alkalies and alkaline Salts ; of \ncommon Salt, - - - 211 \n\nLECTURE VIIL \n\nOn the Improvement of Lands by burning ; chemical Princi- \nples of this Operation. On Irrigation and its Effects. On \nFallowing ; its Disadvantages and Uses. On the convertible \nHusbandry founded on regular Rotations of different Crops. \nOn Pasture. On various Agricultural Objects connected \nwith Chemistry. Conclusion, - - - - - 233 \n\nAPPENDIX. \n\nAn Account of the Results of Experiments on the Produce and \nNutritive Qualities of different Grasses, and other Plants, \nused as the Food of Aniuials. - - - - . - 253 \n\n\n\nA \xc2\xa9\xc2\xa9llliSlS \xc2\xaeW lLm\xc2\xae^WWM^9 ^c \n\n\n\nLECTURE I. \n\n\n\nIntroduction. General Views of the Objects of the \nCourse, and of the Order in itliich they are to he dis- \ncussed, \n\nxT is with great pleasure that I receive the permission \nto address so distinguished and enlightened an Au- \ndience on the subject of Agricultural Chemistry. \n\nThat any thing which I am able to bring forward, \nshould be thought worthy the attention of the Board of \nAgriculture, I consider as an honour; and I shall en-\' \ndeavour to prove iny gratitude, by employing every ex- \nertion to illustrate this department of knowledge, and \nto point out its uses. \n\nIn attempting these objects, the peculiar state of the \ninquiry presents many difficulties to a Lecturer. Agri- \ncultural Chemistry has not yet received a regular and \nsystematic form. It lias been pursued by competent \nexperimenters for a short time only ; the doctrines have \nnot as yet been collected into any elementary treatise ; \nand on an occasion when I am obliged to trust so much \nto my own arrangements, and to my own limited in- \nformation, I cannot but feel diffident as to the interest \nthat may be excited, and doubtful of the success of the \nundertaking. 1 know, however, that your candour will \ninduce you not to expect anything like a iinished work \nupon a science as yet in its infancy ; and I am sure \nyou will receive with indulgence the tirst attempt made \nto illustrate it, in a distinct course of public lectures. \n\nAgricultural Chemistry has for its objects all those \nchanges in the arrangements of matter connected with \nthe growth and nourishment of plants ; the conipara- \n\n\n\n10 \n\nlive values of their produce as food ; the constitution \nof soils ; the manner in which lands are enriched by \nm<inure, or rendered fertile by the difterent processes of \ncultivation. Inquiries of such a nature cannot but be \ninteresting and important, both to the theoretical agri- \nculturist, and to the practical farmer. To the first, \nthey are necessary in "supplying most of the fundamen- \ntal principles on which the theory of the art depends. \nTo the second, they are useful in affording simple and \neasy experiments for directing his labours, and for en- \nabling him to pursue a certain and systematic plan of \nimprovement. \n\nIt is scarcely possible to enter upon any investiga- \ntion in agriculture without finding it connected, more \nor less, with doctrines or eludications derived from che- \nmistry. \n\nIf land be unproductive, and a system of ameliora- \nting it is to be attempted, the sure method of obtaining \nthe object is by determining the cause of its sterility, \nwhich must necessarily depend upon some defect in the \nconstitution of the soil, which may be easily discovered \nby chemical analysis. \n\nSome lands of good apparent texture are yet sterile \nin a high degree ; and common observation and com- \nmon practice afford no means of ascertaining the cause, \nor of removing the effect. The application of chemi- \ncal tests in such cases is obvious ; for the soil must \ncontain some noxious principle which may be easily \ndiscovered, and probably easily destroyed. \n\nAre any of the salts of iron present ? they may be \ndecomposed by lime. Is there an excess of siliceous \nsand ? the system of improvement must depend on the \napplication of clay and calcareous matter. Is there a \ndefect of calcareous matter? the remedy is obvious. \nIs an excess of vegetable matter indicated ? it may be \nremoved by liming, paring, and burning. Is there a \ndeficiency of vegetable matter ? it is to be supplied by \nmanure. \n\nA question concerning the different kinds of lime- \nstone to be employed in cultivation often occurs. To \ndetermine this fully in the common way of experience, \nwould demand a considerable time, perhaps some years. \n\n\n\n11 \n\nand trials which might be injurious to crops ; but by \nsimple chemical tests the nature of a limestone is dis- \ncovered in a few minutes ; and the fitness of its appli- \ncation, whether as a manure for different soils, or as a \ncement, determined. \n\nPeat earth of a certain consistence and composition \nis an excellent manure; but there are some varieties of \npeats which contain so large a quantity of ferruginous \nmatter as to be absolutely poisonous to plants. No- \nthing can be more simple than the chemical operation \nfor determining the nature, and the probable uses of a \nsubstance of this kind. \n\nThere has been no question on which more difference \nof opinion has existed, than that of the state in whicli \nmanure ought to be ploughed into the land ; whether \nrecent, or when it has gone through the process of fer- \nmentation? and this question is still a subject of dis- \ncussion ; but whoever will refer to the simplest princi- \nples of chemistry, cannot entertain a doubt on the sub- \nject. As soon as dung begins to decompose, it tlirows \noff its volatile parts, which are the most valuable and \nmost efficient. Dung which has fermented, so as to be- \ncome a mere soft cohesive mass, has generally lost from \none third to one half of its most useful constituent ele- \nments. It evidently should be applied as soon as fer- \nmentation begins, that it may exert its full action upon \nthe plant, and lose none of its nutritive powers. \n\nIt would be easy to adduce a multitude of other in- \nstances of the same kind ; but sufficient I trust has been \nsaid to prove, that tlie connexion of Chemistry with \nAgriculture is not founded on mere vague speculation, \nbut that it offers principles which ought to be under- \nstood and followed, and which in their progression and \nultimate results, can hardly fail to be highly beneficial \nto the community. \n\nA view of the objects in this Course of Lectures, and \nof the manner in which they are to be treated, will not, \nI hope, be considered as an improper introduction. It \nwill inform you what you are to expect ; it will afford \na general idea of the connexion of the different parts of \nthe subject, and of their relative importance; it will \nenable me to give some historical details of the progress \n\n\n\n12 \n\nof tliis branch of knowledge, and to re/ison from what \nhas been ascertained, concerning what remains to be in- \nvestigated and discovered. \n\nThe phenomena of vegetation must be considered as \nan important l)ranch of the science of organized nature; \nbut tliough exalted above inorganic matter, vegetables \nare yet in a great measure dependent for their exist- \nence upon its laws. I\'liey receive their nourishment \nfrcnn tiie external elements ; they assimilate it by means \nof peculiar organs : and it is by examining their physi- \ncal and chemical constitution, and the substances and \npowers wliich act upon them, and the modilications \nwhich they undergo, that the scientific principles of \nAgricultural Chemistry are obtained. \n\nAccording to these ideas, it is evident that the study \nought to be commenced by some general inquiries into \nthe composition and nature of material bodies, and the \nlaws of their changes. \'^Fhe surface of the earth, the \natmosphere, and the water deposited from it, must either \ntogether or separately .afford all the principles concerned \nin vegetation ; and it is only by examining the chemical \nnature of these principles, that we are capable of dis- \ncovering what is tlie food of plants, and the manner in \nAvhich this food is supplied aiul prepared for their nou- \nrishment. Tlie principles of the constitution of bodies, \nconsequently, will form the fiv^t subject for our consi- \nderation. \n\nBy methods of analysis dependent upon chemical and \nelectrical instruments discovered in late times, it has \nbeen ascertained that all the varieties of material sub- \nstances may be resolved into a comparatively small \nnumber of bodies, which, as they are not capable of \nbeing decompounded, are considered in the present state \nof chemical knowledge as elements. The bodies in- \ncapable of decomposition at present known are forty- \nseven. Of these, thirty-eight are metals ; six are in- \nflammable bodies ; and three substances which unite \nwith metal and inflammable bodies, and form witli \nthem acids, alkalies, earths, or other analogous com- \npounds. The chemical elements acted upon by attrac- \ntive powers comltine in diflcrent aggregates. In their \nsimpler combinations, they produce various crystalline \n\n\n\ni-i \n\nsubstances, distinguislied by the resjularity of their forms. \nIn more complicated arrangements they constitute tlie \nvarieties of vegetable and animal substances, bear the \nhigher character of organization, and are rendered sub- \nservient to the purposes of life. And by the influence \nof heat, light, and electrical powers, there is a constant \nseries of changes ; matter assumes new forms, the de- \nstruction of one order of beings tends to the conserva- \ntion of another, solution and consolidation, decay and \nrenovation, are connected, and whilst the parts of the \nsystem continue in a state of fluctuation and change, \nthe order and harmony of the whole remain unalterable. \n\nAfter a general view has been taken of the nature of \nthe elements, and of the principles of chemical changes, \nthe next object will be tlie structure and constitution of \nplants. In all plants there exists a system of tubes or \nvessels, which in one extremity terminate in roots, and \nat the other in leaves. It is by the capillary action of \nthe roots that fluid matter is taken up from the soil. \nThe sap in passing upwards becomes denser, and more \nfitted to deposit solid matter : it is modified by exposure \nto heat, light, and air in the leaves ; descends througli \nthe bark, in its progress produces new organized mat- \nter ; and is thus in its vernal and autumnal flow, the \ncause of the formation of new parts, and of the more \nperfect evolution of parts already formed. \n\nIn this part of the inquiry I shall endeavour to con- \nnect together into a general view, the ol)scrvation of tbe \nmost enlightened philosophers who have studied the \nphysiology of vegetation. Those of Grew, Malpiglii, \nSennebier, Darwin, and, above all, of Mr. Kniglit. He \nis the latest inquirer into these interesting subjects, and \nhis labours hav^ tended most to illustrate this part of the \neconomy of nature. \n\nThe chemical composition of plants has within the \nlast ten years, been elucidated by the experiments of a \nnumber of chemical philosophers, both in this, and in \nother countries ; and it forms a beautiful part of gene- \nral cliemistry ; it is too extensive to be treated of mi- \nnutely ; but it will be necessary to dwell upon such \nparts of it, as aftbrd practical inferences. \n\nIf the organs of plants be sul)mitted to chemical ana- \n\n\n\n14 \n\nlysis, it is found that their almost infinite diversity ot" \nform, depends upon different arrangements and combi- \nnations of a very few of the elements ; seldom more \nthan seven or eiglit belong to them, and three constitute \nthe greatest part of their organized matter ; and accord- \ning to the manner in which these elements are disposed, \narise the different properties of the products of vegeta- \ntion, whether employed as food, or for other purposes \nand wants of life. \n\nThe value and uses of every species of agricultural \nproduce, are most correctly estimated and applied, \nwhen practical knowledge is assisted by principles \nderived from chemistry. The compounds in vega- \ntables really nutritive as the food of animals, are very \nfew ; farina or the pure matter of starch, gluten, sugar, \nvegetable jelly, oil, and extract. Of these the most \nnutritive is gluten, which approaches nearest in its na- \nture to animal matter, and which is the substance that \ngives to wheat its superiority over other grain. The \nnext in order as to nourishing power is oil, then sugar, \nthen farina; and last of all gelatinous and extractive \nmatters. Simple tests of the relative nourishing pow- \ners of the different species of food, are the relative \nquantities of these substances that they afford by ana- \nlysis ; and though taste and appearance must influence \nthe consumption of all articles in years of plenty, yet \nthey are less attended to in times of scarcity, and on \nsuch occasions this kind of knowledge may be of the \ngreatest importance. Sugar and farina or starch, are \nvery similar in composition, and are capable of being \nconverted into each other by simple chemical processes. \nIn the discussion of their relations, 1 shall detail to you \nthe results of some recent experiments, which will be \nfound possessed of applications both to the economy of \nvegetation, and to some important processes of manu- \nfjicture. \n\nAll the varieties of substances found in plants, are \nproduced from the sap, and the sap of plants is de- \nrived from water, or from the fluids in the soil, and it \nis altered by, or combined with principles derived from \nthe atmosphere. The influence of tlie soil, of water, \nand of air, will therefore be the next subject of consid- \n\n\n\n15 \n\neration. Soils in all cases consist of a mixture of dif- \nferent finely divided earthy matters ; with animal or \nvegetable substances in a state of decomposition, and \ncertain saline ingredients. The earthy matters are \nthe true basis of the soil ; the other parts, whether na- \ntural, or artificially introduced, operate in the same \nmanner as manures. Four earths generally abound in \nsoils, the aluminous, the siliceous, the calcareous, and \nthe magnesian. These earths, as I have discovered, \nconsist of highly inflammable metals united to pure air \nor oxygene ; and they are not, as far as we know, de- \ncomposed or altered in vegetation. \n\nThe great use of the soil is to afford support to the \nplant, to enable, it to fix its roots, and to derive nourish- \nment by its tubes slowly and gradually, from the solu- \nble and dissolved substance mixed with the earths. \n\nThat a particular mixture of the earths is connected \nwith fertility, cannot be doubted: and almost all ste- \nrile soils are capable of being improved, by a modifica- \ntion of their earthy constituent parts. I shall describe \nthe simplest method as yet discovered of analysing soils, \nand of ascertaining the constitution and chemical ingre- \ndients which appear to be connected with fertility ; and \non this subject many of the former difiiculties of inves- \ntigation will be found to be removed by recent inquiries. \n\nThe necessity of w^ater to vegetation, and the luxu- \nriancy of the growth of plants connected with the pre- \nsence of moisture in the southern countries of the old \ncontinent, led to the opinion so prevalent in the earl^\'^ \nschools of philosophy, that water was the great produc- \ntive element, the substance from which all things were \ncapable of being composed, and into which they were \nfinally resolved. The ^<^a6^<o-Tev ,m,\xc2\xa3\xc2\xbb w\'^^^" of the poet, \n\'^ water is the noblest," seems to have been an expres- \nsion of this opinion, adopted by the Greeks from the \nEgyptians, taught by Thales, and revived by the al- \nchemists in late times. Van Helmont in 1610, con- \nceived that he had proved by a decisive experiment, \nthat all the products of vegetables were capable of be- \ning generated from water. His results were shewn to \nbe fallacious by Woodward in 1691 ; but tlie true use \n\n\n\n16 \n\nof water in vegetation was unknown till 1785 ; when \nMr. Cavendish made the grand discovery, that it was \ncomposed of two elastic fluids or gases, inflammable \ngas or hydrogene, and vital gas or oxygene. \n\nAir, like water, was regarded as a pure element by \nmost of the ancient philosophers : a few of the chemi- \ncal inquirers in the sixteenth and seventeenth centuries, \nformed some happy conjectures respecting its real na- \nture. Sir Kenelm Digby in 1660, supposed that it con- \ntained some saline matter, which was an essential food \nof plants. Boyle, Hooke, and Mayow, between 1665 \nand 1680, stated, that a small part of it only was con- \nsumed in the respiration of animals, and in the combus- \ntion of inflammable bodies ; but the true statistical ana- \nlysis of the atmosphere is comparatively a recent la- \nbour, acheived towards the end of the last century by \nScheele, Priestley, and Lavoisier. These celebrated \nmen shewed that its principal elements are two gases, \noxygene and azote, of which the first is essential to \nflame, and to the life of animals, and that it likewise \ncontains small quantities of aqueous vapour, and of car- \nbonic acid gas ; and Lavoisier proved that this last body \nis itself a compound elastic fluid, consisting of charcoal \ndissolved in oxygene. \n\nJethro Tull, in his treatise on Horse- hoeing, publish- \ned in 1733, advanced the opinion that minute earthy \nparticles supplied the whole nourishment of the vege- \ntable world ; that air and water were chiefly useful in \nproducing these particles from the land ; and that ma- \nnures acted in no other way than in ameliorating the \ntexture of the soil, in short, that their agency was me- \nchanical. Tliis ingenious author of the new system of \nagriculture having observed the excellent effects pro- \nduced in farming by a minute division of the soil, and \nthe pulverisation of it by exposure to dew and air, was \nmisled by carrying his principles too fjir. JJuhamcl, in \na work printed in 1754, adopted tlic opinion of Tull, \nand stated that by finely dividing the soil, any number \nof crops might be raised in succession from the same \nland. He atteinpted also to prove, by direct experi- \nments, that vegetables of every kind were capable of \n\n\n\n17 \n\nbeing raised without manure. This celebrated horti- \nculturist lived, however, sulficiently long to alter his \nopinion. The results of his later and most refined ob- \nservations led him to the conclusion, that no single ma- \nterial afforded the food of plants. The general expe- \nrience of farmers had long before convinced the unpre- \njudiced of the truth of the same opinion, and that ma- \nnures were absolutely consumed in the process of vege- \ntation. The exhaustion of soils by carrying off corn \ncrops from them, and the effects of feeding cattle on \nlands, and of preserving their manure, offer familiar il- \nlustrations of the principles ; and several philosophical \ninquirers, particularly Hassenfratz and Saussure, have \nshewn by satisfactory experiments, that animal and ve- \ngetable matters deposited in soils are absorbed by plants, \nand become a part of their organized matter. But though \nneither water, nor air, nor earth, supplies the whole of \nthe food of plants, yet they all operate in the process \nof vegetation. The soil is the laboratory in which the \nfood is prepared. No manure can be taken up by roots \nof plants unless water is present ; and water or its ele- \nments exist in all the products of vegetation. The ger- \nmination of seeds does not take place without the pre- \nsence of air of oxygene gas ; and in the sunshine \nvegetables decompose the carbonic acid gas of the at- \nmosphere, the carbon of which is absorbed, and be- \ncomes a part of their organized matter, and the oxygene \ngas, the other constituent, is given off; and in conse- \nquence of a variety of agencies, the economy of vege- \ntation is made subservient to the general order of the \nsystem of nature. \n\nIt is sliewn by various researches, that the constitu- \ntion of the atmosphere has been always the same since \nthe time that it was first accurately analysed ; and this \nmust in a great measure depend upon tlie powers of \nplants to absorb or decompose the putrifying or decay- \ning remains of animals and vegetables, and the gaseous \neffluvia which they are constantly emitting. Carbonic \nacid gas is formed in a variety of processes of ferment- \nation and combustion, and in the respiration of animals, \nand as yet no other process is known in nature by which \nit can be consumed, except vegetation. Animals pro- \n\n\n\n18 \n\nducc a substance which appears to be a necessary food \nof vegetables ; vegetables evolve a principle necessary \nto the existence of animals ; and these different classes \nof beings seem to be thus connected together in the ex- \nercise of tlieir living functions, and to a certain extent \nmade to depend upon each other for their existence. \nWater is raised from the ocean, diffused through the air, \nand poured down upon the soil, so as to be applied to \nthe purposes of life. The different parts of the atmos- \nphere are mingled together by winds or changes of tem- \nperature, and successively brought in contact with the \nsurface of the earth, so as to exert their fertilizing in- \nfluence. Tlie modifications of the soil, and the appli- \ncation of manures are placed within the power of man, \nas if for the purpose of awakening his industry and of \ncalling forth his powers. \n\nThe theory of the general operation of the more com- \npound manures may be rendered very obvious by sim- \nple chemical principles ; but there is still much to be \ndiscovered with regard to the best methods of render- \ning animal and vegetable substances soluble ; with re- \nspect to the processes of decomposition, how they may \nbe accelerated or retarded, and the means of producing \nthe greatest effects from the tnaterials employed ; these \nsubjects will be attended to in the Lecture on Manures. \n\nPlants are found by analysis to consist principally of \ncharcoal and aeriform matter. They give out by dis- \ntillation volatile compounds, the elements of which are \npure air, inflammable air, coally matter, and azote, or \nthat elastic substance which forms a great part of the \natmosphere, and which is incapable of supporting com- \nbustion. These elements they gain either by their \nleaves from the air, or by their roots from the soil. All \nmanures from organized substances contain the princi- \nples of vegetable matter, which during putrefaction are \nrendered either soluble in water or aeriform \xe2\x80\x94 and in \nthese states they are capable of being assimilated to the \nvegetable organs. \'No one principle affords the pabu- \nlum of vegetable life ; it is neither charcoal nor hydro- \ngene, nor azote nor oxygene alone ; but all of them to- \ngether in various states and various combinations. Or- \n^auic substances as soon as they are deprived of vitality, \n\n\n\n19 \n\nbegin to pass through a series of changes which ends \nin their complete destruction, in the entire separation \nand dissipation of the parts. Animal matters are the \nsoonest destroyed by the operation of air, heat, and \nlight. Vegetable substances yield more slowly, but \nfinally obey the same laws. The periods of the appli- \ncation of manures from decomposing animal and vege- \ntable substances depend upon the knowledge of these \nprinciples, and I shall be able to produce some new \nand important facts founded upon them, which I trust \nwill remove all doubt from this part of agricultural theory. \n\nThe chemistry of the more simple manures ; the ma- \nnures which act in very small quantities, such as gyp- \nsum, alkalies, and various saline substances, has hither- \nto been exceedingly obscure. It has been generally \nsupposed that these materials act in the vegetable econo- \nmy in the same manner as condiments or stimulants in \nthe animal economy, and that they render the common \nfood more nutritive. It seems, however, a much more \nprobable idea, that they are actually a part of the true \nfood of plants, and that they supply that kind of mat- \nter to the vegetable fibre, which is analogous to the bony \nmatter in animal structures. \n\nThe operation of gypsum, it is well known, is ex- \ntremely capricious in this country, and no certain data \nhave hitherto been offered for its application. \n\nThere is, however, good ground for supposing that \nthe subject will be fully elucidated by chemical inquiry. \nThose plants which seem most benefited by its appli- \ncation, are plants which always afford it on analysis. \nClover, and most of the artificial grasses, contain it, \nbut it exists in very minute quantity only in barley, \nwheat, and turnips. Many peat ashes which are sold \nat a considerable price, consist in great part of gypsum, \nwith a little iron, and the first seems to be their most \nactive ingredient. I have examined several of the soils \nto which these ashes are successfully applied, and I \nhave found in them no sensible quantity of gypsum. \nIn general, cultivated soils contain sufficient of this \nsubstance for the use of the grasses : in such casfis, its \napplication cannot be advantageous. For plants re- \n\n\n\n20 \n\nf[iiii\'e only a fertain quantity of raanure ; an excess \nmay be detrimental, and cannot be useful. \n\n*i\'\'lie theory of the operation of alkaline substances, \nis one of the parts of the chemistry of agriculture, most \nsimple and distinct. They are found in all plants, and \ntherefore may l)e regarded as amongst their essential \ningredients. From their powers of combination like- \nwise, they may be useful in introducing vaiious princi- \nples into tiie sap of vegetables, which may be subservient \nto their nourishment. \n\nThe fixed alkalies which were formerly regarded as \nelementary bodies, it has been my good fortune to de- \ncompose. They consist of pure air, united to highly \ninflammable metallic substances ; but there is no reason \nto suppose that they are reduced into their elements in \nany of the processes of vegetation. \n\nIn this part of the Course I shall dwell at considera- \nble length on the important subject of Lime, and I shall \nbe able to oflPer some novel views. \n\nSlacked lime was used by the Romans for manuring \nthe soil in which fruit trees grew. This we are inform- \ned by Pliny. Marie had been employed by the Bri- \ntons and the Gauls from the earliest times, as a top \ndressing for land. But the precise period in which \nburnt lime first came into general use in the cultivation \nof land, is, 1 believe, unknown. The origin of the ap- \nplication from the early practices is sufficiently obvious; \na substance which has been used with success in gar- \ndening, must have been soon tried in farming; and in \ncountries where marie was not to be found, calcined \nlimestone would be naturally employed as a substitute. \n\nThe elder writers on agricultin-e had no correct no- \ntions of the nature of lime, limestone and marie, or of \ntheir effects ; and this was the necessary consequence \nof the imperfection of the chemistry of the age. Cal- \ncareous matter was considered by the alchemists as a \npeculiar earth, which in the fire became combined with \ninflammable acid ; and Evelyn and Hartlib, and, still \nlater, Lisle, in their works on husbandry, have charac- \nterized it merely as a hot manure of use in cold lands. \nIt is to Dr. Black of Edinburgh that our first distinct \n\n\n\n21 \n\nrudiments of knowledge on the subject, are owing. \nAbout the year 1755, this celebrated professor proved, \nby the most decisive experiments, that limestone and \nall its modifications, marbles, chalks, and marles, con- \nsist principally of a peculiar eartli united to an aerial \nacid : that the acid is given out in burning, occasioning \na loss of more than 40 per cent., and that the lime in \nconsequence becomes caustic. \n\nThese important facts immediately applied with equal \ncertainty to the explanation of the uses of lime, both as \na cement and as a manure. As a cement, lime applied \nin its caustic state acquires its hardness and durability, \nby absorbing the aerial (or as it has been since called \ncarbonic) acid, which always exists in small quantities \nin the atmosphere, it becomes as it were again limestone. \n\nChalks, calcareous marles, or powdered limestone, \nact merely by forming a useful earthy ingredient of the \nsoil, and their efBcacy is proportioned to the deficiency \nof calcareous matter, which in larger or smaller quanti- \nties seems to be an essential ingredient of all fertile \nsoils ; necessary perhaps to tlieir proper texture, and as \nan ingredient in the organs of plants. \n\nBurnt lime, in its first effect, acts as a decomposing \nagent upon animal or vegetable matter, and seems to \nbring it into a state on which it becomes more rapidly \na vegetable nourishment ; gradually, however, the lime \nis neutralized by carbonic acid, and converted into a \nsubstance analogous to chalk ; but in this case it more \nperfectly mixes with the other ingredients of the soil, \nis more generally diffused and finely divided : and it is \nprobably more useful to land than any calcareous sub- \nstance in its natural state. \n\nThe most considerable fact made known with regard \nto limestone within the last few years, is owing to Mr. \nTennant. It had been long known that a particular \nspecies of limestone found in different parts of tlie \nNorth of England, when applied in its burnt and slack- \ned state to land in considerable quantities, occasioned \nsterility, or considerably injured the crops for many \nyears. Mr. Tennant in 1800, by a chemical examina- \ntion of this species of limestone, ascertained, that it \ndiffered from common limestones by containing magne- \n\n\n\n22 \n\nsian earth ; and by several experiments he proved tliat \nthis earth was prejudicial to vegetation, when applied \nin large quantities in its caustic state. Under common \ncircumstances the lime from the magnesian limestone is, \nhowever, used in moderate quantities upon fertile soils \nin Leicestershire, Derbyshire, and Yorkshire, with good \neffect ; and it may be applied in greater quantities to \nsoils containing very large proportions of vegetable \nmatter. Magnesia when combined with carbonic acid \ngas, seems not to be prejudicial to vegetation, and in \nsoils rich in manure, it is speedily supplied with this \nprinciple from the decomposition of the manure. \n\nAfter this nature and operation of manures have been \ndiscussed, the next and the last subject for our conside- \nration, will be some of the operations of husbandry \ncapable of elucidation by chemical principles. \n\nThe cliemical theory of fallowing is very simple. \nFallowing affords no new source of riches to the soil. \nIt merely tends to produce an accumulation of decom- \nposing matter, which in the common course of crops \nwould be employed as it is formed, and it is scarcely \npossible to imagine a single instance of a cultivated soil, \nwhich can be supposed to remain fallow for a year with \nadvantage to the farmer. The only cases where this \npractice is beneficial seems to be in the destruction of \nweeds, and for cleansing foul soils. \n\nThe chemical theory of paring and burning, I shall \ndiscuss fully in this part of the Course. \n\nIt is obvious that in all cases it must destroy a certain \nquantity of vegetable matter, and must be principally \nuseful in cases in which there is an excess of this mat- \nter in soils. Burning, likewise renders clays less co- \nherent, and in this way greatly improves their texture, \nand causes them to be less permable to water. \n\nThe instances in which it must be obviously prejudi- \ncial, are those of sandy dry siliceous soils, containing \nlittle animal or vegetable matter. Here it can only be \ndestructive, for it decomposes that on which the soil de- \npends for its productiveness. \n\nThe advantages of irrigation, though so lately a sub- \nject of much attention, were well known to the ancients ; \nand more than two centuries ago the practice was re- \n\n\n\n26 \n\ncommended to the farmers of our country by Lord Ba- \ncon ; " meadow-watering," according to the statements \nof this illustrious personage, (given in his Natural His- \ntory, in the article Vegetation,) acts not only by sup- \nplying useful moisture to the grass ; but likewise the \nwater carries nourishment dissolved in it, and defends \nthe roots from the effects of cold. \n\nNo general principles can be laid down respecting \nvthe comparative merit of the different systems of culti- \nvation, and the different systems of crops adopted in \ndifferent districts, unless the chemical nature of the soil, \nand the physical circum*stances to which it is exposed \nare fully known. Stiff coherent soils are those most \nbenefited by minute division and aeration, and in the \ndrill system of husbandry, these effects are produced \nto the greatest extent ; but still the labour and expense \nconnected with its application in certain districts, may \nnot be compensated for by the advantages produced. \nMoist climates are best fitted for raising the artificial \ngrasses, oats, and broad-leaved crops ; stiff aluminous \nsoils, in general, are most adapted for wheat crops, and \ncalcareous soils produce excellent sain-foin and clover. \n\nNothing is more wanting in agriculture, than experi- \nments in which all the circumstances are minutely and \nscientifically detailed. This art will advance with ra- \npidity in proportion as it becomes exact in its methods. \nAs in physical researches all the causes should be con- \nsidered ; a difference in the results may be produced, \neven by the fall of a half an inch of rain more or less \nin the course of a season, or a few degrees of tempera- \nture, or even by a slight difference in the sub-soil, or in \nthe inclination of the land. \n\nInformation collected after views of distinct inquiry, \nwould necessarily be more accurate, and more capable \nof being connected with the general principles of \nscience ; and a few histories of the results of truly phi- \nlosophical experiments in agricultural chemistry, would \nbe of more value in enlightening and benefiting the far- \nmer, than the greatest possible accumulation of imper- \nfect trials conducted merely in the empirical spirit. It \nis no unusual occurrence for persons who argue in fa- \nvour of practice and experience, to condemn generally \n\n\n\n24 \n\nall attempts to improve agi-iculture by philosophical in- \nquiries and chemical methods. That much vague spe- \nculation may be found in the works of those who have \nlightly taken up agricultural chemistry, it is impossible \nto deny. It is not uncommon to find a number of chan- \nges rung upon a string of technical terms, such as oxy- \ngene, hydrogene, carbon, and azote, as if the science de- \npended upon words, rather than upon things. But this \nis in fact an argument for the necessity of the establish- \nment of just principles of chemistry on the subject. \nWhoever reasons upon agriculture, is obliged to recur \nto this science. He feels that it is scarcely possible to \nadvance a step without it : and if he is satisfied witli \ninsuflficient views, it is not because he prefers them to \naccurate knowledge, but generally because they are \nmore current. If a person journeying in the night \nwishes to avoid being led astray by the ignis fatuus, \nthe most secure method is to carry a lamp in his own \nhand. \n\nIt has been said, and undoubtedly with great truth, \nthat a philosophical chemist would most probably make \na very unprofitable business of farming ; and this cer- \ntainly would be the case, if he were a mere philosophical \nchemist ; and unless he had served his apprenticeship \nto the practice of the art, as well as the theory. But \nthere is reason to believe, that lie would be a more suc- \ncessful agriculturist than a person equally uninitiated \nin farming, but ignorant of chemistry altogether ; his \nscience, as far as it went, would be useful to him. But \nchemistry is not the only kind of knowledge required, \nit forms a small part of the philosophical basis of agri- \nculture ; but it is an important part, and whenever ap- \nplied in a proper manner must produce advantages. \n\nIn proportion as science advances all the principles \nbecome less complicated, and consequently more useful. \nAnd it is then that their application is most advanta- \ngeously made to the arts. The common labourer can \nnever be enlightened by the general doctrines of phi- \nlosophy, but he will not refuse to adopt any practice, of \nthe utility of which he is fully convinced, because it \nhas been founded upon tliese principles. The mariner \ncan trust to the compass, though he may be wholly un- \n\n\n\n25 \n\nacquainted with the discoveries of Gilbert on masjuet- \nism, or the refined principles of tliat science developed \nby the genius of jEpinus. The dyer will use his bleach- \ning liquor, even though he is perhaps ignorant not only \nof the constitution, but even of the name of the sub- \nstance on which its powers depend. The great pur- \npose of chemical investigation in Agriculture, ought un- \ndoubtedly to be the discovery of improved methods of \ncultivation. But to this end, general scientific princi- \nples and practical knowledge, are alike necessary. The \ngerms of discovery are often found in rational specula- \ntions ; and industry is never so efficacious as when as- \nsisted by science. \n\nIt is from the higher classes of the community, from \nihe proprietors of land ; those who are fitted ])y their \neducation to form enlightened plans, and by their for- \ntunes to carry such plans into execution ; it is from these \nthat the principles of improvement must flow to the la- \nbouring classes of the community ; and in all cases the \nbenefit is mutual ; for the interest of the tenantry must \nbe always likewise the interest of the proprietors of \nthe soil. The attention of the labourer will be more \nminute, and he will exert himself more for improve- \nment when he is certain he cannot deceive his employ- \ner, and has a conviction of the extent of hii^ knowledge. \nIgnorance in the possessor of an estate of the manner \nin which it ought to be treated, generally leads either \nto inattention or injudious practices in the tenant or the \nbailiff. ^^ Agnun pessimum mulctari cujus Dominus \nnon docet sed audit vUliciim.^^ \n\nThere is no idea more unfounded than that a great \ndevotion of time, and a minute knowledge of general \nchemistry is necessary for pursuing experiments on the \nnature of soils or the properties of manures. Nothing \ncan be more easy than to discover whether a soil effer- \nvesces, or changes colour by the action of an acid, or \nwhether it burns when heated ; or what weight it loses \nby heat : and yet these simple indications may ])e of \ngreat importance in a system of cultivation. Tlie ex- \npense connected with chemical inquiries is extremely \ntrifling ; a small closet is sufficient for containing all the \nmaterials required. The most important experiments \nmay be made by means of a small portable apparatus ; \n\nD \n\n\n\n26 \n\na few phials, a few acids, a lamp and a crucible are all \nthat are necessary, as I shall endeavour to prove to you, \nin the course of these lectures. \n\nIt undoubtedly happens in agricultural chemical ex- \nperiments conducted after the most refined theoretical \nviews, that there are many instances of failure, for one \nof success ; and this is inevitable from the capricious \nand uncertain nature of the causes that operate, and \nfrom the impossibility of calculating on all the circum- \nstances that may interfere ; but this is far from proving \nthe inutility of such trials ; one happy result which can \ngenerally improve the methods of cultivation is worth the \nlabour of a whole life ; and an unsuccessful expertiment \nwell observed, must establish some truth, or tend to re- \nmove some prejudice. \n\nEven considered merely as a philosophical science, \nthis department of knowledge is highly worthy of cul- \ntivation. For what can be more delightful than to trace \nthe forms of living beings and their adaptations and pe- \nculiar purposes ; to examine the progress of inorganic \nmatter in its different processes of change, till it attain \nits ultimate and highest destination ; its subserviency to \nthe purposes of man. \n\nMany of the sciences are ardently pursued, and con- \nsidered as proper objects of study for all refined minds, \nmerely on account of the intellectual pleasure they af- \nford ; merely because they enlarge our views of nature, \nand enable us to think more correctly with respect to \nthe beings and objects surrounding us. How much \nmore then is this department of inquiry worthy of at- \ntention, in which the pleasure resulting from the love \nof truth and of knowledge is as great as in any other \nbranch of philosophy, and in which it is likewise con- \nnected with much greater practical benefits and advan- \ntages. " JSTihil est melius, nihil uherius, nihil homine \nlibero dignius.^^ \n\nDiscoveries made in the cultivation of the earth, are \nnot merely for the time and country in which they are \ndeveloped, but they may be considered as extending to \nfuture ages, and as ultimately tending to benefit the \nw hole human race : as affording subsistence for genera- \ntions yet to come ; as multiplying life, and not only \nmultiplying life, but likewise providing for its enjoyment. \n\n\n\nLECTURK II \n\nOf the general Powers of Matter which influence Ve- \ngetation. Of Gravitation, of Cohesion, of Chemical \nAttraction, of Heat, of Light, of Electricity, ponder- \nable Substances, Elements of Matter, particularly \nthose found in Vegetables, Laws of their Combina- \ntions and ^Arrangements. \n\nA HE great operations of the farmer are directed to- \nwards the production or improvement of certain classes \nof vegetables ; they are either mechanical or chemical, \nand are, conse(3[uently, dependent upon the laws which \ngovern common matter. Plants themselves are, to a \ncertain extent, submitted to these laws ; and it is neces- \nsary to study their effects, both in considering the phse- \nnomena of vegetation, and the cultivation of the vege- \ntable kindom. \n\nOne of the most important properties belonging to \nmatter is gravitation, or the power by wiiich masses of \nmatter are attracted towards each other. It is in con- \nsequence of gravitation that bodies thrown into the at- \nmosphere fall to the surface of the earth, and that the \ndifferent parts of the globe are preserved in their pro- \nper positions. Gravity is exerted in proportion to the \nquantity of matter. Hence all bodies placed above the \nsurface of the earth fall to it in right lines, which if \nproduced would pass through its centre ; and a body \nfalling near a high mountain, is a little bent out of the \nperpendicular direction by the attraction of the moun- \ntain, as has been shewn by the experiments of Dr. Mas- \nkelyne on Schehallien. \n\nGravitation has a very important influence on the \ngrowth of plants ; and it is rendered probable, by the \nexperiments of Mr. Knight, that they owe the peculiar \ndirection of their roots and branches almost entirely to \nthis force. \n\nThat gentleman fixed some seeds of the garden bean \n\n\n\n2.8 \n\noil ilie circnmrereiicft of a wheel, which in one instance \nwas placed vertically, and in the other horizontally, \nand made to revolve, by means of another wheel work- \ned hj water, in such a manner, that the number of the \nrevolutions could be regulated ; the beans were supplied \nwitli moisture, and were placed under circumstances fa- \nvourable to germination. The greatest velocity of mo- \ntion given to the wheel was such, that it performed two \nhundred and fifty revolutions in a minute. It was found \nthat in all cases the beans grew, and that the direction \nof the roots and stems was influenced by the motion of \nthe wheel. When the centrifugal force was made su- \nperior to tlie force of gravitation, which was supposed \nto l)e done when the vertical Mheel performed 150 re- \nvi)lutions in a minute, all the radicles, in whatever way \nthey were protruded from the position of the seeds, \nturned their points outwards from the circumference of \nthe wheel, and in their subsequent growth receded near- \nly at right angles from its axis ; the germens, on the \ncontrary took the opposite direction, and in a few days \ntheir points all met in the centre of the wheel. \n\nWhen the centrifugal force was made merely to mo- \ndify the force of gravitation in the horizontal wheel, \nwhere the greatest velocity of revolution was given, the \nradicles pointed downwards about ten degrees below, \nand the germens as many degrees above the horizontal \nline of the wheel\'s motion ; and the deviation from the \nperpendicular was less in proportion, as the motion was \nless rapid.* \n\nThese facts afford a rational solution of this curious \nproblem, respecting wliich different philosophers have \ngiven such different opinions ; some referring it to the \nnature of the sap, as De la Hire, others, as Darwin, to \nthe living powers of the plant, and the stimulus of air \nupon the leaves, and of moisture upon the roots. The \neffect is now shewn to be connected with mechanical \ncauses ; and there seems no other power in nature to \nwhich it can Avith propriety be referred but gravity, \n\n* Fig. I, represents the form of the experiment vhen the horizon- \ntal wheel was made to peHorm 250 revolutions in a minute. \n\nfig. 2, represents the case in which the vertical wheel performed \n150 revolutions. \n\n\n\n29 \n\nwhich acts uuiversally, and wliich must tend to dispose \nthe parts to take a uniform direction. \n\nIf plants in general owe their perpendicular direction \nto gravity, it is evident that the number of plants upon \na given part of the earth\'s circumference, cannot be in- \ncreased by making the surface irregular, as some per- \nsons have supposed. Nor can more stalks rise on a \nhill than on a spot equel to its base ; for the slight ef- \nfect of the attraction of the hill, would be only to make \nthe plants deviate a- very little from the perpendicular. \nWhere horizontal layers are pushed forth, as in certain \ngrasses, particularly such as the fiorin, lately brought \ninto notice by Dr. Richardson, more food may, however, \nbe produced upon an irregular surface ; but the princi- \nple seems to apply strictly to corn crops. \n\nThe direction of the radicles and germens is such, \nthat both are supplied with food, and acted upon by \nthose external agents which are necessary for their de- \nvelopment and growth. The roots come in contact with \nthe fluids in the ground; the leaves arc exposed to \nlight and air ; and the same grand law which preserves \nthe planets in their orbits, is thus essential to the func- \ntions of vegetable life. \n\nWhen two pieces of polished glass are pressed to- \ngether they adhere to each otlier, and it requires some \nforce to separate them. This is said to depend upon \nthe attraction of cohesion. The same attraction gives \nthe globular form to drops of water, and enables fluids \nto rise in capillary tubes ; and hence it is sometimes \ncalled cajjillary attraction. This attraction, like gravi- \ntation, seems common to all matter, and may be a mo- \ndification of the same general force ; like gravitation, \nit is of great importance in vegetation. It preserves the \nforms of aggregation of the parts of plants, and it seems \nto be a principal cause of the absorptions of fluids by \ntheir roots. \n\nIf some pure magnesia, the calcined magnesia of \ndruggists, be thrown into distilled vinegar, it gradually \ndissolves. This is said to be owing to chemical attrac- \ntion^ the power by which difierent species of matter \ntend to unite into one compound. Various kinds of \nmatter unite with different deirrees of force : tlins sul- \n\n\n\nphuric acid and magnesia unite with more readiness \nthan distilled vinegar and magnesia ; and if sulphuric \nacid be poured into a mixture of vinegar and magnesia, \nin which the acid properties of the vinegar have been \ndestroyed by the magnesia, the vinegar will be set free, \nand the sulphuric acid will take its place. This chemi- \ncal attraction is likewise called chemical affinity. It is \nactive in most of the phaenomena of vegetation. The \nsap consists of a number of ingredients, dissolved in \nwater by chemical attraction ; and it appears to be in \nconsequence of the operation of this power, that certain \nprinciples derived from the sap are united to the vege- \ntable organs. By the laws of chemical attraction, dif- \nferent products of vegetation are changed, and assume \nnew forms ; the food of plants is prepared in the soil ; \nvegetable and animal remains are changed by the ac- \ntion of air and Avater, and inade fluid or aeriform ; rocks \nare broken down and converted into soils ; and soils \nare more finely divided and fitted as receptacles for the \nroots of plants. \n\nThe different powers of attraction tend to preserve \nthe arrangements of matter, or to unite them in new \nforms. If there were no opposing powers, there would \nsoon be a state of perfect quiescence in nature, a kind \nof eternal sleep in the physical world. Gravitation is \ncontinually counteracted by mechanical agencies, by \nprojectile motion, or the centrifugal force; and their \njoint agencies occasion the motion of the heavenly bodies. \nCohesion and chemical attraction are opposed by the \nrepulsive energy of heat, and the harmonious cycle of \nterrestrial changes is produced by their mutual operations. \n\nHeat is capable of being communicated from one body \nto other bodies ; and its common effect is to expand \nthem, to enlarge them in all their dimensions. This is \neasily exemplified. A solid cylinder of metal after be- \ning heated will not pass through a ring barely sufficient \nto receive it when cold. When water is heated in a globe \nof glass having a long slender neck, it rises in the neck ; \nand if heat be applied to air confined in such a vessel \ninverted above water, it makes its escape from the ves- \nsel and passes through the water. Thermometers are \ninstruments for measuring degrees of heat by the ex- \n\n\n\np. 5C> \n\n\n\n\n\npausion of iiuids in narrow tubes. Mercury is general- \nly used, of which 100,000 parts at the freezing point of \nwater become 101,835 parts at the boiling point, and on \nFahrenheit\'s scale these parts are divided into 180 de- \ngrees. Solids, by a certain increase of heat, become \nfluids, and fluids gases, or elastic fluids. Thus ice is \nconverted by heat into water, and by still more heat it \nbecomes steam : and heat disappears, or, as it is called, \nis rendered latent during the conversion of solids into \nfluids, or fluids Jinto gases, and re- appears or becomes \nsensible when gases become fluids, or fluids solids : \nlience cold is produced during evaporation, and heat \nduring the condensation of steam. \n\nThere are few exceptions to the law of expansion of \nbodies by heat, which seem to depend either upon some \nchange in their chemical constitution, or on their be- \ncoming crystallized. Clay contracts by heat, which \nseems to be owing to its giving off water. Cast iron and \nantimony, when melted, crystallize in cooling and ex- \npand. Ice is much lighter than water. Water expands \na little even before it freezes, and it is of the greatest \ndensity at about 41\xc2\xae or 42*^, the freezing point being \n32\xc2\xae ; and this circumstance is of considerable importance \nin the general economy of nature. The influence of the \nchanges of seasons and of the position of the sun on the \nphenomena of vegetation, demonstrates the effects of heat \non the functions of plants. The matter absorbed from \nthe soil must be in a fluid state to pass into their roots, \nand when the surface is frozen they can derive no nou- \nrishment from it. The activity of chemical changes like- \nwise is increased by a certain increase of temperature, \nand even the rapidity of the ascent of fluids by capilla- \nry attraction. \n\nThis last fact is easily shewn by placing in each of \ntwo wine glasses a similar hollow stalk of grass, so bent \nas to discharge any fluid in the glasses slowly by capil- \nlary attraction ; if hot water be in one glass, and cold \nwater in the other, the hot water will be discharged \nmuch more rapidly than the cold water. The fermen- \ntation and decomposition of animal and vegetable sub- \nstances require a certain degree of heat, which is conse- \nquently necessary for the preparation of the food of \n\n\n\n32 \n\nplants ; and as evaporation is more rapid in proportion \nas the temperature is higher, the superfluous parts of the \nsap are most readily carried oflf at the time its ascent is \nquickest. \n\nTwo opinions are current respecting the nature of \nheat. By some philosophers it is conceived to be a pe- \nculiar subtle fluid, of which the particles repel each other, \nbut have a strong attraction for the particles of other \nmatter. By others it is considered as a motion or vibra- \ntion of the particles of matter, which is supposed to dif- \nfer in velocity in different cases^ and thus to produce the \ndifferent degrees of temperature. Whatever decision be \nultimately made respecting these opinions, it is certain \nthat there is matter moving in tlie space between us and \nthe heavenly bodies capable of communicating heat; the \nmotions of which are rectilineal : thus the solar rays pro- \nduce heat in acting on the surface of the earth. The \nbeautiful experiments of Dr. Herschel have shewn that \nthere are rays transmitted from the sun which do not il* \nluminate ; and which yet produce more heat than the vi- \nsible rays; and Mr. Ritter and Dr. Wollaston have \nshewn that there are other invisible rays distinguished \nby their chemical effects. \n\nThe different influence of the different solar rays on \nvegetation have not yet been studied ; but it is certain \nthat the rays exercise an influence independent of the \nheat they produce. Thus plants kept in the dark in a \nhot-house grow luxuriantly, but they never gain their \nnatural colours ; their leaves are white or pale, and their \njuices watery and peculiarly saccharine. \n\nWhen a piece of sealing- wax is rubbed by a woollen \ncloth, it gains the power of attracting light bodies, such \nas feathers or ashes. In this state it is said to be elec- \ntrical; and if a metallic cylinder, placed upon a rod of \nglass, is brought in contact with the sealing-wax, it like- \nwise gains the momentary poAver of attracting light bo- \ndies, so that electricity, like heat, is communicable. \nWhen two light bodies receive the same electrical in- \nfluence, or are electrified by the same body, they repel \neach other. When one of them is acted on by sealing- \nwax, and the other by glass that has been rubbed by \nwoollen, they attract each other : hence it is said, that \n\n\n\n33 \n\nbodies similarly electrified repel each other, and bodies \ndissimilarly electrified attract each other: and the elec- \ntricity of glass is called vitreous or positive electricity,* \nand that of sealing-wax resinous or negative electri- \ncity. \n\nWhen of two bodies made to rub each other one is \nfound positively electrified, the other is always found \nnegatively electrified, and, as in the common electrical \nmachine, these states are capable of being communica- \nted to metals placed upon rods or pillars of glass. Elec- \ntricity is produced likewise by the contact of bodies ; \nthus a piece of zinc and of silver give a slight electri- \ncal shock when they are made to touch each other, and \nto touch the tongue : and when a number of plates of \ncopper and zinc, 100 for instance, are arranged in a pile \nwith cloths moistened in salt and water, in the order of \nzinc, copper, moistened cloth, zinc, copper, moistened \ncloth, and so on, they form an electrical battery which will \ngive strong shocks and sparks, and which is possessed \nof remarkable chemical powers. The luminous phseno- \nmena produced by common electricity are well known. \nIt would be improper to dwell upon them in this place. \nThey are the most impressive effects occasioned by this \nagent; and they offer illustrations of lightning and thunder. \n\nElectrical changes are constantly taking p]^ce in na- \nture, on the surface of the earth, and in the atmosphere ; \nbut as yet the eifects of this power in vegetation have \nnot been correctly estimated. It has been shewn by ex- \nperiments made by means of the Voltaic battery (the in- \nstruments composed of zinc, copper, and water) that com- \npound bodies in general are capable of being decompo- \nsed by electrical powers, and it is probable, that the va- \nrious electrical phsenoraena occurring in our system, \nmust influence both the germination of seeds and the \ngrowth of plants. 1 found that corn sprouted mucii \nmore rapidly in water positively electrified by the Vol- \ntaic instrument, than in water negatively electrified ; and \nexperiments made upon the atmosphere shew that clouds \nare usually negative ; and as when a cloud is in one state \nof electricity, the surface of the earth beneath is brought \ninto the opposite state, it is probable that in common \ncases the surface of the earth is positive, \n\n\xc2\xa3 \n\n\n\n34 \n\nl)ifferent opinions are enteitained amongst scientific \nmen respecting the nature of electricity ; by some, the \nphaenoraena are conceived to depend upon a single sub- \ntile fluid in excess in the bodies, said to be positively \nelectrified, in deficiency in tlie bodies said to be nega- \ntively electrified. A second class suppose the effects to \nbe produced by two different fluids, called by them the \nvitreous fluid and the resinous fluid ; and others regard \nthem as affections or motions of matter, or an exhibition \nof attractive powers, similar to those which produce che- \nmical combination and decomposition ; but usually ex- \nerting their action on masses. \n\nThe different powers that have been thus generally \ndescribed, continually act upon common matter, so as to \nchange its form, and produce arrangements fitted for the \npurposes of life. Bodies are either simple or compound. \nA body is said to be simple, when it is incapable of be- \ning resolved into any other forms of matter. Thus gold, \nor silver, though they may be melted by heat, or dissol- \nved in coi\'rosive menstrua, yet are recovered unchanged \nin their properties, and they are said to be simple bodies. \nA body is considered as compound, when two or more \ndistinct substances are capable of being produced from \nit ; thus marble is a compound body, for by a strong \nheat, it is converted into lime, and an elastic fluid is dis- \nengaged in the process : and the proof of our knowledge \nof the true composition of a body is, that it is capable of \nbeing reproduced by the same substances as those into \nwhich is had been decomposed ; thus by exposing lime \nfor a long while to the elastic fluid, disengaged during \nits calcination, it becomes converted into a substance si- \nmilar to powdered marble. The term element has the \nsame meaning as simple or undecompoundedbody; but \nit is applied merely with reference to the present state \nof chemical knowledge. It is probable, that as yet we \nare not acquainted with any of the true elements of mat- \nter ; many substances, formerly supposed to be simple, \nhave been lately decompounded, and the chemical ar- \nrangement of bodies must be considered as a mere ex- \npression of facts, the results of accurate statical experi- \nments. \n\nVegetable substances in general are of a very com- \n\n\n\n65 \n\npound nature, and consist of a great number of elements, \nmost of which belong likewise to the other kingdoms of \nnature, and are found in various form*. Their more \ncomplicated arrangements are best understocd after \ntheir simpler forms of combination have been examin- \ned. \n\nThe number of bodies which I shall consider as at \npresent undecomposed, are, as was stated in the intro- \nductory lecture, three acidifying and solvent substances, \nsix inflammable bodies, and thirty-eight metals. \n\nIn most of the inorganic compounds, the nature of \nwhich is well known, into which these elements enter, \nthey are combined in definite proportions ; so that if the \nelements be represented by numbers, the proportions in \nwhich they combine are expressed either by those num- \nbers, or by some simple multiples of them. \n\n1 shall mention, in a few words, the characteristic \nproperties of the most important simple substances, and \nthe numbers representing the proportions in which they \ncombine in those cases, where they have been accurate- \nly ascertained. \n\n1. Oxygene forms about one-fifth of the air of our at- \nmosphere. It is an elastic fluid, at all known tempera- \ntures. Its specific gravity is to that of air as 10967 to \n10000. It supports combustion with much more vivid- \nness than common air ; so that if a small steel wire, or \na watch-spring, having a bit of inflamed wood attached \nto it, be introduced into a bottle filled with the gas, it \nburns with great splendour. It is respirable. It is \nvery slightly soluble in water. The number represent- \ning the proportion in which it combines is 15. It may \nbe made by heating a mixture of the mineral called man- \nganese, and sulphuric acid together, in a proper vessel, \nor by heating strongly red lead, or red precipitate of \nmercury. \n\n2. Chlorine, or oxymuriatic gas, is, like oxygene, a \npermanent elastic fluid. Its colour is yellowish green; \nits smell is very disagreeable; it is not respirable ; it \nsupports the combustion of all the common inflammable \nbodies except charcoal ; its specific gravity is to that of \nair as 24677 to 10000; it is soluble in about half its vo- \nlume of water, and its solution in water destroys vege- \n\n\n\n86 \n\ntable colours. Many of the metals (such as arsenic uu \ncopper) take tire spontaneously when introduced into a \njar or bottle tilled with the gas. Chlorine may be pro- \ncured by heating together a mixture of spirits of salt or \nmuriatic acid, and manganese. The number represent- \ning the proportion in which this gas enters into combi- \nnation is 67. \n\n3. Fluorine^ or the fluoric principle. This substance \nhas such strong tendencies of combination, that as yet, \nno vessels have been found capable of containing it in \nits pure form. It may be obtained combined with hy- \ndrogene, by applying heat to a mixture of fluor or Der- \nbyshire spar, and sulphuric acid, and in this state it is \nan intensely acid compound, a little heavier than water, \nand which becomes still denser by combining with wa- \nter. \n\n4. Hydrogene, or inflammable air, is the lightest \nknown substance ; its specific gravity is to that of air as \n732 to 10000. It burns by the action of an inflamed \ntaper, when in contact with the atmosphere. The pro- \nportion in which it combines is represented by unity, \nor 1. It is procured by the action of diluted oil of vi- \ntroil, or hydro-sulphuric acid on filings of zinc or iron. \nit is the substance employed for filling air balloons. \n\n5. Azote is a gaseous substance, not capable of being \ncondensed by any known degree of cold : its specific \ngravity is to that of common air as 9516 to 10000. It \ndoes not enter into combustion under common circum- \nstances, but may be made to unite with oxygene by the \nagency of electrical fire. It forms nearly four-fifths of \nthe air of the atmosphere ; and may be procured by \nburning phosphorous in a confined portion of air. The \nnumber representing the proportion in which it combines \nis 26. \n\n6. Carbon is considered as the pure matter of char- \ncoal, and it may be procured by passing spirits of wine \nthrough a tube heated red. It has not yet been fused ; \nbut rises in vapour at an intense heat. Its specific gra- \nvity cannot be easily ascertained ; but that of the dia- \nmond, which cannot chemically be distinguished from \npure carbon, is to that of water as 3500 to 1000. Char- \ncoal has the remarkable property of absobing several \n\n\n\na: \n\ntimes its volume of cliff\'erent elastic iluids, which are ca- \npable of being expelled from it by heat. The number \nrepresenting it is 11.4. \n\n7. Sulphur is the pure substance so well known by \nthat name : its specific gravity is to that of water as \n1990 to 1000. It fuses at about 220\xc2\xae Fahrenheit ; and \nat between 500\xc2\xae and 600\xc2\xae takes fire, if in contact with \nthe air, and burns with a pale blue flame. In this pro- \ncess it dissolves in the oxygene of the air, and produces \na peculiar acid elastic fluid. The number representing \nit is 30. \n\n8. PJiosphorus is a solid of a pale red colour, of spe- \ncific gravity 1770. It fuses at 90\xc2\xb0, and boils at 550\xc2\xae. \nIt is luminous in the air at common temperatures, and \nburns with great violence at 150*>, so tliat it must be \nhandled with great caution. Tlie number represent- \ning it is 20. It is procured by digesting together bone \nashes and oil of vitroil, and strongly heating the fluid \nsubstance so produced with powdered charcoal. \n\n9. Boron is a solid of a dark olive colour, infusible \nat any known temperature. It is a substance very late- \nly discovered, and procured from boracic acid. It burns \nwith brilliant sparks, when heated in oxygene, but not \nin chlorine. Its specific gravity and the number repre- \nsenting it, are not yet accurately known. \n\n10. Platinum is one of the noble metals, of rather \na duller white than silver, and the heaviest body in na- \nture ; its specific gravity being 21500. It is not acted \nupon by any acid menstrua except such as contain \nchlorine : it requires an intense degree of heat for its fu- \nsion. \n\n11. The properties of ^oMare well known. Its spe- \ncific gravity is 19277. It bears the same relation to \nacid menstrua as platinum : it is one of the characteris- \ntics of both these bodies, that they are very difficultly \nacted upon by sulphur. \n\n12. Silver is of specific gravity 10400, it burns more \nreadily than platinum or gold, which require the intense \nheat of electricity. It readily unites to sulphur. The \nnumber representing it is 205. \n\n13. Mercury is the only known metal fluid at the \ncommon temperature of the atmosphere ; it boils at 660\xc2\xb0, \n\n\n\n38 \n\nand freezes at 39 below 0. Its specific gravity is 13560 \nThe number representing it is 380. \n\n14. Copper is of specific gravity 8890. It burns when \nstrongly heated with red flame tinged with green. The \nnumber representing it is 120. \n\n15. Cobalt is of specific gravity 7700. Its point of \nfusion is very high, nearly equal to that of iron. In its \ncalcined or oxidated state, it is employed for giving a \nblue colour to glass. \n\n16. JVickel is of a white colour : its specific gravity \nis 8820. This metal and cobalt agree with iron, it be- \ning attractible by the magnet. The number representing, \nnickel is 111. \n\n17. Iron is of specific gravity 7700. Its other pro- \nperties are well known. The number representing it \nis 103. \n\n18. Tin is of specific gravity 729 1 ; it is a very fusi- \nble metal, and burns when ignited in the air : the num- \nber representing the proportion in which it combines \nis 110. \n\n19. Zinc is one of the most combustible of the com- \nmon metals. Its specific gravity is about 7210. It is \na brittle metal under common circumstances ; but when \nheated may be hammered or rolled into thin leaves, and \nafter this operation is malleable. The number repre- \nsenting it is 68. \n\n20. Lead is of specific gravity 11352; it fuses at a \ntemperature rather higher than tin. The number re- \npresenting it is 398. \n\n21. Bismuth is a brittle metal of specific gravity \n9822. It is nearly as fusible as tin ; when cooled slow- \nly it crystallizes in cubes. The number representing \nit is 135. \n\n22. Antimony is a metal capable of being volatilized \nby a strong heat. Its specific gravity is 6800. It burns \nwhen ignited with a faict white light. The number re- \npresenting it is 170. \n\n23. Arsenic is of a bluish white colour, of specific \ngravity 8310. It may be procured by heating the pow- \nder of common w hite arsenic of the shops strongly in \na Florence flask with oil. The metal rises in vapour, \nand condenses in the neck of the flask. The number \nrepresenting it is 90. \n\n\n\na9 \n\n24. Manganesmn may be procured from the mineral \ncalled manganese, by intensely igniting it in a forge \nmixed with charcoal powder. It is a metal very diffi- \ncult of fusion, and very combustible ; its specific gravi- \nty is 6850. The number representing it is 177. \n\n25. Potassium is the lightest known metal, being \nonly of specific gravity 850. It fuses at about 150\xc2\xb0, \nand rises in vapour at a heat a little below redness. It \nis a highly combustible substance, takes fire when \nthrown upon water, burns with great brilliancy, and \nthe product of its combustion dissolves in the water, \nThe number representing it is 75. It may be made by \npassing fused caustic vegetable alkali, the pure kali of \ndruggists, through iron turnings strongly ignited in a \ngun barrel, or by the electrization of potash by a strong \nVoltaic battery. \n\n26. Sodium may be made in a similar manner to po- \ntassium. Soda, or the mineral alkali, being substituted \nfor the vegetable alkali. It is of specific gravity 940. \nIt is very combustible. When thrown upon water, it \nswims on its surface, hisses violently, and dissolves, \nbut does not inflame. The number representing it is 88. \n\n27. Barium has as yet been procured only by elec- \ntrical powers and in verj\' minute quantities, so that its \nproperties have not been accurately examined. The \nnumber representing it appears to be 180. \n\nStrontium the 28, Calcium the 29th, Magnesium \nthe 30th, Silicum the 31st, Muminiun the 32d, Zirco- \nnum the 33d, Glueinum the 34th, and Ittrium the 35th \nof the undecompounded bodies, like barium, have either \nnot been procured absolutely pure, or only in such mi- \nnute quantities that their properties are little known ; \nthey are formed either by electrical powers, or by the \nagency of potassium, from the dilFerent earths whose \nnames they bear, with the change of the termination in \num ; and the numbers representing them are believed \nto be 90 strontium, 40 calcium, 38 magnesium, 3l sili- \ncum, 33 aluminum, 70 zirconum, 39 glueinum, 111 it- \ntrium. \n\nOf the remaining simple bodies, twelve are metals, \nmost of which, like those just mentioned, can only be \nprocured Avith very great difficulty ; and the substances in \n\n\n\n40 \n\ngeneral from which they are procured are very rare in \nnature. They are Palladium, Rhodium^ Osmium, Iri- \ndium, Columbium, Chromium, Molybdenum, Cerium, \nTellurium, Tungstenum, Titanium, Uranium. The \nnumbers representing these last bodies have not yet been \ndetermined with sufficient accuracy to render a refer- \nence to them of any utility. \n\nThe undecompounded substances unite with each \nother, and the most remarkable compounds are formed \nby the combinations of oxygene and chlorine with in- \nflammable bodies and metals ; and these combinations \nusually take place with much energy, and are associated \nwith fire. \n\nCombustion in fact, in common cases, is the process \nof the solution of a body in oxygene, as happens when \nsulphur or charcoal is burnt ; or the fixation of oxygene \nby the combustible body in a solid form, which takes \nplace when most metals are burnt, or when phosphorus \ninflames ; or the production of a fluid from both bodies, \nas when hydrogene and oxygene unite to form water. \n\nWhen considerable quantities of oxygene or of chlo- \nrine unite to metals or inflammable bodies, they often \nproduce acids: thus sulphureous, phosphoric, and bo- \nracic acids are formed by a union of considerable quan- \ntities of oxygene w ith sulphur, phosphorus, and boron : \nand muriatic acid gas is formed by the union of chlorine \nand hydrogene. \n\nWhen smaller quantities of oxygene or chlorine unite \nwith inflammable bodies or metals, they form substances \nnot acid, and more or less soluble in water ; and the \nmetallic oxides, the fixed alkalies, and the earths, all \nbodies connected by analogies, are produced by the \nunion of metals with oxygene. \n\nThe composition of any compounds, the nature of \nwhich is well known, may be easily learnt from the \nnumbers representing their elements ; all that is neces- \nsary, is to know how many proportions enter into union. \nThus potassa, or the pure caustic vegetable alkali, con- \nsists of one proportion of potassium and one of oxygene, \nand its constitution is consequently 75 potassium, 15 \noxygene. \n\nCarbonic acid is composed of two proportions of oxy- \ngene 30, and one of carbon 11.4. \n\n\n\n41 \n\nAgain, lime consists of one proportion of caldum \nand one of oxygene, and it is composed of 40 of cal- \ncium and 15 of oxygene. And corbonate of lime, or \npure chalk, consists of one proportion of carbonic acid \n41.4, and one of lime 55. \n\nWater consists of two proportions of hydrogene 2, \nand one of oxygene 15 ; and when water unites to other \nbodies in definite proi)ortions, the quantity is 17, or \nsome multiple of 17, i. e. 34 or 51, or 68, ^c. \n\nSoda, or the mineral alkali, contains two proportions \nof oxygene to one of sodium. \n\ntdLmmonia, or the volatile alkali, is composed of six \nproportions of hydrogene and one of azote. \n\nAmongst the earths. Silica, or the earth of flints, pro- \nbably consists of two proportions of oxygene to one of \nsilicum ; and Magnesia, Strontia, Baryta or Barytes, \nAlumina, Zircona, Glucina, and Ittria, of one propor- \ntion of metal and one of oxygene. \n\nThe metallic oxides in general consist of the metals \nunited to from one to four proportions of oxygene ; and \nthere are, in some cases, many different oxides of the \nsame matal ; thus there are three oxides of lead ; the \nyellow oxide, or massicot, contains tvvo proportions of \noxygene ; the red oxide, or minium, three ; and the puce \ncoloured oxide four proportions. Again there are two \noxides of copper, the hlacTc and the orange; the black \ncontains two proportions of oxygene, the orange one. \n\nFor pursuing such experiments on tlie composition \nof bodies as are connected with agricultural chemistry, \na few only of the undecompounded substances are ne- \ncessary ; and amongst the compounded bodies, the com- \nmon acid^, the alkalies, and the earths, are the most es- \nsential svibstances. The elements found in vegetables, \nas has been stated in the introductory lecture, are.very \nfew. Oxygene, hydrogene, and carbon, constitute the \ngreatest part of their organized matter. Azote, phos- \nphorus, sulphur, manganesum, iron, silicum, calcium, \naluminum, and magnesium likewise, in different ar- \nrangements, enter into their composition, or are found in \nthe agents to which they are exposed ; and these twelve \nundecompounded substances are the elements, the study \n\n\n\n42 \n\nof which is of tKe most importance to the agricultural \nchemist. \n\nTiic doctrine of definite combinations, as will be \nshewn in the following lectures, will assist us in gaining \njust views respecting the composition of plants, and the \neconomy of the vegetable kingdom ; but the same ac- \ncuracy of weight and measure, the same statistical re- \nsults which depend upon the uniformity of the laws that \ngovern dead matter, cannot be expected in operations \nwhere the powers of life are cencerned, and where a \ndiversity of organs and of functions exists. The class- \nes of definite inorganic bodies, even if we include all \nthe crystalline arrangements of the mineral kingdom, \nare few, compared with the forms and substances be- \nlonging to animated nature. Life gives a peculiar char- \nacter to all its productions ; the power of attraction and \nrepulsion, combination and decomposition, are subser- \nvient to it ; a few elements, by the diversity of their \narrangement, are made to form the most diflferent sub- \nstances ; and similar substances are produced from \ncompounds, whith, when superficially examined, ap- \npear entirely different. \n\n\n\nLECTUHE III. \n\nOn the Organization of Plants. Of the Roots, Trunk, \nand Branches. Of their Structure. Of the Epider- \nmis. Of the cortical and alburnous Parts of Leaves, \nFlowers, and Seeds. Of the chemical Constitution \nof the Organs of Plants, and the Substances found \nin them. Of mucilaginous, saccharine, extractive, \nresinous, and oily Substances, and other vegetable \nCompounds, their Arrangements in the Organs of \nPlants, their Composition, Changes, and Uses. \n\nV ARIETY characterises the vegetable kingdom, yet \nthere is an analogy between the forms and the functions \nof all the diJSferent classes of plants, and on this analo- \ngy the scientific principles relating to their organization \ndepend. \n\nVegetables are living structures distinguished from \nanimals by exhibiting no signs of perception, or of vo- \nluntary motion ; and their organs are either organs of \nnourishment or of reproduction ; organs for the preser- \nvation and increase of the individual, or for the multi- \nplication of the species. \n\nIn the living vegetable system there are to be consi- \ndered, the exterior form, and the interior, constitution. \n\nEvery plant examined as to external structure, dis- \nplays at least four systems of organs, or some analo- \ngous parts. First, the Root ; secondly, the Trunk and \nBranches, or Stem ; thirdly, the Leaves ; and fourthly, \nthe Flowers or Seeds. \n\nThe 7\'oot is that part of the vegetable which least \nimpresses the eye ; but it is absolutely necessary. It \nattaches the plant to the surface, is its organ of nourish- \nment, and the apparatus by which it imbibes food from \nthe soil. The roots of plants, in their anatomical di- \nvision, are very similar to the trunk and branches. The \nroot may indeed be said to be a continuation of the trunk \nterminating in minute ramifications and filaments, and \n\n\n\n44 \n\nnot iu leaves : and by burying the branches of certain \ntrees in tlic soil, and elevating the roots iu the atmos- \nphere, there is, as it were, an inversion of the functions, \nthe roots produce buds and leaves, and the" brances \nshoot out into radical fibres and tubes. This experiment \nwas made by Woodward on the willow, and has been \nrepeated by a number af physiologists. \n\nWhen the branch or the root of a tree is cut trans- \nvetsely, it usually exhibits three distinct bodies : the \nbark, the wood, and the pith ; and these again are in- \ndividually susceptible of a new division. \n\nThe bark when perfectly formed, is covered by a thin \ncuticle or epidermis^ which may be easily separated. \n\'It is generally composed of a number of laminae or \nscales, which in old trees are usually in a loose and de- \ncaying state. The epidermis is not vascular, and it \nmerely defends the interior parts from injury. In fo- \nrest trees, and in the larger shrubs, the bodies of which \nare firm, and of strong texture, it is a part of little im- \nportance; but in the reeds, the grasses, canes, and the \nplants having hollow stalks, it is of great use, and is \nexceedingly strong, and in the microscope seems com- \nposed of a kind of glassy net-work, which is princi- \npally siliceous earth. \n\nThis is the case in wheat, in the oat, in different spe- \ncies of equisetum, and above all, in the rattan, the epi- \ndermis of which contains a suflRcient quantity of flint \nto give light when struck by steel ; or two pieces rub- \nbed together produce sparks. This fact first occurred \nto me in 1798, and it led to experiments, by which I \nascertained that siliceous earth existed generally in the \nepidermis of the hollow plants. \n\nThe siliceous epidermis serves as a support, protects \nthe bark from the action of insects, and seems to per- \nform a part in the economy of these feeble vegetable \ntribes, similar to that performed in the animal kingdom, \nby the shell of the crustaceous insects. \n\nImmediately beneath the epidermis is the parenchy- \nma. It is a soft substance consisting of cells filled with \nfluid, having almost always a greenish tint. The cells \nin the parenchymatous part, when examined by the mi- \ncroscope, appear hexagonal. This form, indeed, is that \nusually affected by the cellular membranes iji vegeta* \n\n\n\n45 \n\ntiles, and it seems to be the result of the general re-ac- \ntion of the solid parts, similar to that which takes place \nin the honey-comb. This arrangement, which has \nusually been ascribed to the skill and artifice of the bee, \nseems as Dr. Wollaston has observed, to be merely the \nresult of. the mechanical laws which influence the pres- \nsure of cylinders composed of soft materials, the nests \nof solitary bees being uniformly circular. \n\nThe innermost part of the bark is constituted by the \ncortical layers, and their numbers vary with the age of \nthe tree. On cutting the bark of a tree of several years \nstanding, the productions of different periods may be \ndistinctly seen, though the layer of every particular year \ncan seldom be accurately defined. \n\nThe cortical layers are composed of fibrous parts \nwhich appear interwoven, and which are transverse and \nlongitudinal. The transverse are membraneous and \nporous, and the longitudinal are generally composed of \ntubes. \n\nThe functions of the parenchymatous and cortical \nparts of the bark are of great importance. The tubes \nof the fibrious parts appear to be the organs that receive \nthe sap ; the cells seem destined for the elaboration of \nits parts, and for the exposure of them to the action of \nthe atmosphere, and the new matter is annually produ- \nced in the spring, immediately on the inner surface of \nthe cortical layer of the last year. \n\nIt has been shewn by the experiments of Mr. Knight, \nand those made by other physiologists, that the sap de- \nscending tiirough the bark after being modified in the \nleaves, is the principal cause of the growth of the tree ; \nthus, if the bark is wounded, the principal formation of \nnew bark is on the upper edge of the wound ; and \nwhen the wood has been removed, the formation of \nnew wood takes place immediately beneath the bark : \nyet it would appear from the late observations of M. \nPalisot de Beauvois, that the sap may be transferred to \nthe bark, so as to exert its nutritive functions, indepen- \ndent of any general system of circulation. That gentle- \nman separated different portions of bark from the rest \nof the bark in several trees, and found that in most in- \nstances the separated bark grew in the same manner as \nthe bark in its natural state. The experiment was tri- \n\n\n\n46 \n\ned with most success on the lime-tree, the maple, and \nthe lilac ; the layers of bark were removed in August \n1810, and in the spring of the next year, in the case of \nthe maple and the lilac, small annual shoots were pro- \nduced in the parts where the bark was insulated.* \n\nThe wood of trees is composed of an external or li- \nving part, called alhurmim, or sap-wood, and of an in- \nternal or dead part, the heart-wood. The alburnum is \nwhite, and full of moisture, and in young trees and an- \nnual shoots it reaches even to the pith. The alburnum \nis the great vascular system of the vegetable through \nwhich the sap rises, and the vessels in it extend from \nthe leaves to the minutest filaments in the roots. \n\nThere is in the alburnum a membranous substance com- \nposed of cells, which are constantly filled with the sap \nof the plant, and there are in the vascular system seve- \nral different kind of tubes ; Mirbel has distinguished \nfour species, the simple tubes, the porous tubes, the tra- \ncheae, and i\\\\Q false trachem.-\\ \n\nTlie tubes, which he has called simple tubes, seem \nto contain the resinous or oily fluids peculiar to differ- \nent plants. \n\nThe porous tubes likewise contain these fluids ; and \ntheir use is probably that of conveying them into the sap \nfor the production of new arrangements. \n\nThe tracheae contain fluid matter, which is always \nthin, watery, and pellucid, and these organs, as well as \nthe false trachese, probably carry off water from the \ndenser juices, which are thus enabled to consolidate for \nthe production of new wood. \n\nIn the arrangement of the fibres of the w^ood, there \nare two distinct appearances. There are series of white \nand shining laminae which shoot from the centre towards \nthe circumference, and these constitute what is called \nthe silver grain of the wood. \n\nThere are likewise numerous series of concentric lay- \ners which are usually called the spurious grain, and \ntheir number denotes the age of the tree.J \n\n* Fig. 3, represents the result of the experiment on the maple. \nJournal de Physique, Scptemher 1811, page 210. \n\nt Fig. 4, 5, 6, and 7, represent Mirbel\'s idea of the simple tubes, \nthe porous tubes, the tracliese, and the false tracheae. \n\nI Fig. 8, represents the section of an elm branch, which exhibits \n\n\n\n47 \n\nThe silver grain is elastic and contractile, and it has \nbeen supposed by Mr. Knight, that the change of volnme \nproduced in it by change of temperature is one of the \nprincipal causes of the ascent of the sap. The fibres of \nit seem always to expand in the morning, and contract \nat night; and the ascent of the juices, as was stated \nin the last Lecture, depends principally on the agency \nof heat. \n\nThe silver grain is most distinct in forest trees ; but \neven annual shrubs have a system of fibres similar to it. \nThe analogy of nature is constant and uniform, and si- \nmilar effects are usually produced by similar organs. \n\nThe jpith occupies the centre of the wood ; its texture \nis membranous ; it is composed of cells, which are cir- \ncular towards the extremity, and hexagonal in the cen- \ntre of the substance. In the first infancy of the vegeta- \nble, the pith occupies but a small space. It gradually \ndilates, and, in annual shoots and young trees offers a \nconsiderable diameter. In the more advanced age of \nthe tree, acted on by the heart- wood, pressed by the \nnew layers of the alburnum, it begans to diminish, and \nin very old forest trees disappears altogether. \n\nMany different opinions have prevailed with regard \nto the use of the pith. Dr. Hales supposed, that it was \nthe great cause of the expansion and developement of \nthe other parts of the plant; that being the most interi- \nor, it was likewise the most acted upon of all the or- \ngans, and that from its re-action the phenomena of their \ndevelopement and growth resulted. \n\nLinnaeus, whose lively imagination was continually \nemployed in endeavours to discover analogies between \nthe animal and vegetable systems, conceived " tliat the \npith performed for the plant the same functions as the \nbrain and nerves in animated beings." He considered it \nas the organ of irritability and the seat of life. \n\nThe latest discoveries have proved that these two \nopinions are equally erroneous. Mr. Knight has remo- \nved the pith in several young trees, and they continued \nto live and to increase. \n\nthe tubular structure and the silver and spurious grain. Fig. 9, re- \npresents the section of part of the branch of an oak. Fig. 10, that \nof the branch of an ash. \n\n\n\n48 \n\nIt is evidently then only an organ of secondary im- \nportance. In early shoots, in vigorous growth, it is fill- \ned with moisture, and it is a reservoir, perhaps, of fluid \nnourishment at the time it is most wanted. As the heart- \nvrood forms, it is more and more separated from the li- \nving part, the alburnum ; its functions become exstinct, \nit diminishes, dies, and at last disappears. \n\nThe tendrils, the spines, and other similar parts of \nplants, are analogious in their organization to the branch- \nes, and offer a similar corticle and alburnous organiza- \ntion. It has been shewn, by the late observations of \nMr. Knight, that the directions of tendrils, and the spi- \nral form they assume, depend upon the unequal action \nof light upon them, and a similar reason has been as- \nsigned by M. Decandolle to account for the turning of \nthe parts of plants towards the sun ; that ingenious phy- \nsiologist supposes that the fibres are shortened by the \nchemical agency of the solar rays upon thejn, and that, \nconsequently, the parts will move towards the light. \n\nThe leaves, the great sources of the permanent beau- \nty of vegetation, though infinately diversified in their \nforms, are in all cases similar in interior organization, \nand perform the same functions. \n\nThe alburnum spreads itself from the foot-stalks into \nthe very extremity of the leaf; it retains a vascular sys- \ntem and its living powers ; and its peculiar tubes, par- \nticularly the tracheae, may be distinctly seen in the \nleaf.* \n\nThe green membranous substance may be considered \nas an extension of the parenchyma, and the fine and thin \ncovering as the epidermis. Thus the organization of \nthe roots and branches may be traced into the leaves, \nwhich present, however, a more perfect, refined, and \nminute structure. \n\nOne great use of the leaves is, for the exposure of the \nsap to the influence of the air, heat, and light. Their \nsurface is extensive, the tubes and cells very delicate, \nand their texture porous and transparent. \n\nIn the leaves much of the water of the sap is evapo- \n\n* Fig. 1 1) represents part of a leaf of a vine magnified and cut, so \nas to exhibit the tracheae ; it is copied, as are also the preceding fig- \nures, from Grew\'s Anatomy of Plants, \n\n\n\n49 \n\nmteil ; it is combined witii new principles, and iitled foi* \nits organizing functions, and probably passes, in its pre- \npared state, from the extreme tubes of the alburnum in- \nto the ramifications of the cortical tubes, and then de- \nscends through the bark. \n\nOn the upper surface of leaves, which is exposed to \nthe sun, the epidermis is thick but transparent, and is \ncomposed of matter possessed of little organization, \nwhich is either principally earthy, or consists of some \nhomogenous chemical substance. In the grasses it is \npartly siliceous, in the laurel resinous, and in the ma- \nple and thorn, it is principally constituted by a substance \nanalogious to wax. \n\nBy these arrangements any evaporation, except from \nthe appropriated tubes, is prevented. \n\nOn the lower surface the epidermis is a thin transpa- \nrent membrane full of cavities, and it is probably alto- \ngether by this surface that moisture and the principles \nof the atmosphere necessary to vegetation are absorb- \ned. \n\nIf a leaf be turned, so as to present its lower surface \nto the sun, its fibres will twist so as to bring it as much \nas possible into its original position ; and all leaves ele- \nvate themselves on the foot-stalk during their exposure \nto the solar light, and as it were move towards the sun. \n\nThis effect seems in a great measure dependent upon \nthe mechanical and chemical agency of light and heat. \nBonnet made artificial leaves, which, when a moist sponge \nwas held under the lower surface, and a heated iron \nabove the upper surface, turned exactly in the same man- \nner as the natural leaves. This however can be consider- \ned only as a very rude imitation of the natural process, \n\nAVhat Linnaeus has called the sleep of the leaves, ap- \npears to depend wholly upon the defect of the action of \nlight and heat, and the excess of the operation of mois- \nture. \n\nThis singular but constant phenomenon, had never \nbeen scientifically observed, till the attention of the bo- \ntanist of Upsal was fortunately directed to it. He was \nexamining particularly a species of lotus, in which four \nflow ers had appeared during the day, and he missed two \nin the evening; by accurate inspection, he soon discover^ \n\n\n\n50 \n\ned that these two were hidden by the leaves which had \nclosed round them. Such a circumstance could not he \nlost upon so acute an observer. lie immediately took \na lantern, went into his garden, and witnessed a series of \ncurious facts before uuknown. All the simple leaves of \nthe plants he examined, had an arrangement totally dif- \nferent from their arrangement in the day : and the greater \nnumber of them were seen closed or folded together. \n\nThe sleep of leaves is, in some cases, capable of be- \ning produced artificially. Decandolle made this experi- \nment on the sensitive plant. By confining it in a dark \nplace in the daytime, the leaves soon closed ; but on il- \nluminating the chamber with many lamps, they again ex- \npanded. So sensible were they to the eflPects of light and \nradiant heat. \n\nIn the greater number of plants the leaves annually \ndecay, and are repruduced; their decay takes place ei- \nther at the conclusion of the summer, as in very hot cli- \nmates, when they are no longer supplied with sap, in \nconsequence of the dryness of the soil, and the evapo- \nrating powers of heat; or in the autumn, as in the north- \nern climates at the commencement of the frosts. The \nleaves preserve their functions in common cases no long- \ner than there is a circulation of fluids through them. In \nthe decay of the leaf, the colour assumed seems to de- \npend upon the nature of the chemical change, and as \nacids are generally developed, it is usually either red- \ndish brown or yellow ; yet there are great varieties. \nThus in the oak, it is a bright brown ; in the beech, \norange ; in the elm, yellow ; in the vine, red ; in the sy- \ncamore, dark brown ; in the cornel tree, purple ; and in \nthe woodbine, blue. \n\nThe cause of the preservation of the leaves of ever- \ngreens through the winter is not accurately known. From \nthe experiments of Hales, it appears that the force of \nthe sap is much less in plants of this species, and pro- \nbably there is a certain degree of circulation throughout \nthe winter; their juices are less watery than those of \nother plants, and probably less liable to be congealed \nby cold, and they arc defended by stronger coatings \nfrom the action of the elements. \n\nThe production of the other parts of the plant takes \n\n\n\n5i \n\nplace at the time the leaves are most vigorously perform- \ning their functions. If the leaves are stripped off from \na tree in spring, it uniformly dies, and when many of the \nleaves of forest trees are injured by blasts, the trees al- \nways become stag-headed and unhealthy. \n\nThe leaves are necessary for the existence of the in- \ndividual tree, the Jlowers for the continuance of the spe- \ncies. Of all the parts of plants they are the most refi- \nned, the most beautiful in their structure, and appear as \nthe master- work of nature in the ve2;etable kiu2;dom. \nThe elegance of their tints, the variety of their forms, \nthe delicacy of their organization, and the adaptation of \ntheir parts are all calculated to awaken our curiosity, and \nexcite our admiration. \n\nIn the tlower there are to be observed, 1st, the calyx, \nor the green membranous part forming the support for \nthe coloured floral leaves. This is vascular, and agrees \nwith the common leaf in its texture and organization ; \nit defends, supports, and nourishes the more perfect \nparts. 2d. The corolla, which consists either of a sin- \ngle piece, when it is called monopetalous, or of many \npieces, when it is called polypetalous. It is usually \nvery vivid in its colours, is filled with an almost infinite \nvariety of small tubes of the porous kind ; it encloses \nand defends the essential parts in the interior, and sup- \nplies the juices of the sap to them. These parts are, \n3d, the stamens and the pistils. \n\nThe essential part of the stamens are the summits or \nanthers, which are usually circular and of a highly vas- \ncular texture, and covered with a fine dust called the \npollen. \n\nThe pistil is cylindrical, and surmounted by the style; \nthe top of which is generally round and protuberant.* \n\nIn the pistil, when it is examined by the microscope, \ncongeries of spherical forms may usually be perceived, \nwhich seem to be the basis of the future seeds. \n\nIt is upon the arrangement of the stamens and the pis- \ntils that the Linnasan classification is founded. The \nnumbers of the stamens and pistils in the same flower, \ntheir arrangements, or their division in different flowers, \n\n* Fig. 1 2, represents the common lily, a, the corolla, bbbib, the \nanthei-s, r, the pistil. \n\n\n\n52 \n\nare the circumstances which guided the Swedish philo- \nsopher, and enabled him to form a system admirably \nadapted to assist the memory, and render botany of easy \nacquisition : and which, though it does not always as- \nsociate together the plants most analogous to each in \ntheir general characters, is yet so ingeniously contrived \nas to denote all the analogies of their most essential parts. \n\nThe pistil is the organ which contains the rudiments \nof the seed ; but the seed is never formed as a repro- \nductive germ, without the influence of the pollen, or dust \non the anthers. \n\nThis mysterious impression is necessary to the con- \ntinued succession of the different vegetable tribes. It \nis a feature which extends the resemblances of the dif- \nferent orders of beings, and establishes, on a great scale, \nthe beautiful analogy of nature. \n\nThe ancients had observed, that different date trees \nbore different flowers, and that those trees producing \nflowers which contained pistils bore no fruit, unless in \nthe immediate vicinity of such trees as produced flow- \ners containing stamens. This long established fact \nstrongly impressed the mind of Malpighi, who ascer- \ntained several analogous facts with regard to other ve- \ngetables. Grew, however, was the first person who at- \ntempted to generalize upon them, and much just rea- \nsoning on the subject may be found in his works. Lin- \nnaeus gave a scientific and distinct form to that which \nGrew had only generally observed, and has the glory of \nestablishing what has been called the sexual system, upon \nthe basis ofminute observations and accurate experiments. \n\nThe seed, the last production of vigorous vegetation, \nis wonderfully diversified in form. Being of the high- \nest importance to the resources of nature, it is defend- \ned above all other parts of the plant ; by soft pulpy sub- \nstances, as in the esculent fruits, by thick membranes, as \nin the leguminous vegetables, and by hard shells, or a \nthick epidermis, as in the palms and grasses. \n\nIn every seed there is to be distinguished, 1, the or- \ngan of nourishment ; 2, the nascent plant, or thep/zt?He; \n8, the nascent root, or the radicle. \n\nIn the common garden bean, the organ of nourish- \nment is divided into two lobes called cotyledons ; tire \n\n\n\n53 \n\nplume is the small white point between the ufper pan \nof the lobes ; and the radicle is the small curved coue \nat their base.* \n\nIn wheat, and in many of the grasses, the orgaji of \nnourishment is a single part, and these plants are cEill- \ned monocotyledonous. In other cases it consists of more \nthan two parts, when the plants are called polycutyUdo- \nnous. In the greater number of instances it is, how- \never, simply divided into two, and is dicotyledonous^ \n\nThe matter of the seed, when examined in its com- \nmon state, appears dead and inert ; it exhibits neither \nthe forms nor the functions of life. But let it be acted \nupon by moisture, heat, and air, and its organized pow- \ners are soon distintly developed. The cotyledons ex- \npand, the membranes burst, the radicle acquires new \nmatter, descends into the soil, and the plume rises to- \nwards the free air. By degrees, the organs of nourish- \nment of dicotyledonous plants become vascular, and are \nconverted into seed leaves, and the perfect plant ap- \npears above the soil. Nature has provided the eleoients \nof germinations on every part of the surface ; water and \npure air and heat are universally active, and the means \nfor the preservation and multiplication of life, are at \nonce simple and grand. \n\nTo enter into more minute details on the vegetable \nphysiology would be incompatable with the objects of \nthese Lectures. 1 have attempted only to give such ge- \nneral ideas on the subject, as may enable the philoso- \nphical agriculturist to understand the functions of plants ; \nthose who wish to study the anatomy of vegetables, as \na distinct science, will find abundant materials in the \nworks of the authors I have quoted, page, 13, and like- \nwise in the writings of Linuceus, Uesfontaines, Decan- \ndolle, de Saussure, Bonnet, and Smith. \n\nThe history of the peculiarities of structure in the \ndiff\'erent vegetable classes, rather belongs to botanical \nthan agricultural knowledge. As I mentioned in the \ncommencement of this Lecture, their organs are pos- \nsessed of the most distinct analogies, and are governed \n\n* Fig. 1 3, represents the garden bean, aa, the cotyledons, b, the \nplume, c, the radicle. \n\n\n\n51 \n\nby the same laws. In the grasses and palms, the cor- \ntical layers are larger in proportion than the other parts ; \nbnt their uses seem to be the same as in forest trees. \n\nIn bulbous roots, the alburnous substance forms the \nlargest part of the vegetable ; but in all cases it seems \nto contain the sap, or solid materials deposited from the \nsap. \n\nThe slender and comparatively dry leaves of the pine \nand the cedar perform the same functions as the large \nand juicy leaves of the fig-tree or the walnut. , \n\nEven in the cryptogamia, where no flowers are dis- \ntinct, still there is every reason to believe that the pro- \nduction of the seed is effected in the same w ay as in the \nmore perfect plants. The mosses and lichens, which \nbelong to this family, have no distinct leaves or roots, \nbut they are furnished with filaments which perform the \nsame functions ; and even in the fungus and the mushroom \nthere is a system for the absorption and aeration of the \nsap. \n\nIt was stated in the last Lecture, that all the different \nparts of the plants are capable of being decomposed into \na few elements. Their uses as food, or for the purpo- \nses of the arts, depend upon compound arrangements of \nthose elements which are capable of being produced ei- \nther from their organized parts, or from the juices they \ncontain ; and the examination of the nature of these sub- \nstances, is an essential part of Agricultural Chemis- \n\ntry. \n\nOils are expressed from the fruits of many plants; \nresinous fluids exude from the wood ; saccharine mat- \nters are afforded by the sap ; arid dyeing materials are \nfurnished by leaves, or the petals of flowers : but par- \nticular processes are necessary to separate the different \ncompound vegetable substances from each other, such as \nmaceration, infusion or digestion in water, or in spirits \nof wine: butthe aj)plicationandthe nature of these pro- \ncesses will be better understood when the chemical na- \nture of the substances is known; the consideration of \nthem will therefore be reserved for another place in this \nLecture. \n\nThe cojnpound substances found in vegetables are, 1, \ngum, or anucilage, and its different modifications : 2, \n\n\n\nr. &i \n\n\n\n\n\n\nFi\'<7.3. \n\n\n\n\nFig" io. \n\n\n\n\n55 \n\nbtarch ; 3, sugar ; 4, albumen ; 5, gluten ; 0, gum clas^- \ntic; 7, extract; 8, tannin ; 9, indigo; 10, narcotic princi- \nple; 11, bitter principle ; 12, wax; 13, resins ; 14, cam- \nphor; 15, fixed oils ; 16, volatile oils ; 17, woody fil)re; 18, \nacids; 19, alkalies; earths, metallic oxides, and saline \ncompounds. \n\nI shall describe generally the properties and compo- \nsition of these bodies, and the manner in which they are \nprocured. \n\n1. Gum is a substance which exudes from certain \ntrees ; it appears in the form of a thick fluid, but soon \nhardens in the air, and becomes solid ; wlien it is white, \nor yellowish white, more or less transparent, and some- \nwhat brittle ; its specific gravity varies from 1300 to \n1490. \n\nThere is a great vai\'iety of gums, ])ut tlie best known \nare gum arabic, gum Senegal, gum tragacanth, and the \ngum of the plum or cherry tree. Grum is soluble in wa- \nter, but not soluble in spirits of w^ine. If a solution of \ngum be made in water, and spirits of wine or alcohol \nbe added to it, the gum separates in the form of w^hitc \nflakes. Gum can be made to inflame only with\'difficul- \nty; much moisture is given oft* in the process, which \ntakes place with a dark smoke and feeble blue flame, \nand a coal remains. \n\nThe characteristic properties of gum are its easy so- \nlubility in water, and its insolubility in alcohol. Dif- \nferent chemical substances have been proposed for as- \ncertaining the presence of gum, but tliere is reason to \nbelieve that few of them aft\'ord accurate results ; and \nmost of them (particularly the metallic salts,) which pro- \nduce changes in solutions of gum, may be conceived to \nact rather upon some saline compounds existing in the \ngum, than upon the pure vegetable principle. Ur. \nThomson has proposed an aqueous solution of silica in \npotassa, as a test of the presence of gum in solutions \xe2\x80\x94 \nhe states that the gum and silica are precipitated toge- \nther \xe2\x80\x94 ^this test, however, cannot be applied with cor- \nrect results in cases when acids are present. \n\nMucilage must be considered as a variety of gum; it \nagrees with it in its most important properties, but seems \nto liave less attraction for water. \xe2\x80\x94 According to Uermb- \nstadt, when \xc2\xa3;um and mucilage are dissohrd <o\xc2\xabrether w \n\n\n\n56 \n\nwater, the mucilage may be separated by means of sul- \nphuric acid \xe2\x80\x94 mucilage may be procured fro^n linseed, \nfrom the bulbs of the hyacinth, from the leaves of the \nmarshmallovts ; from several cf the lichens, and from \nmany other vegetable substances. \n\nFrom the analysis of M. M. Gay Lussac and The- \n\nnard, it appears that gum arable contains in 100 parts: \n\nof carbon - - 42,23 \n\n\xe2\x80\x94 oxygene - - 50,84 \n\n\xe2\x80\x94 hydrogene - - 6,93 \n\nwith earthy matter a small quantity of saline and. \n\nor of carbon - - 42,23 \noxygene and hydrogene ^ \nin the proportions ne- C 57,77 \ncessary to form water 3 \n\nThis estimation agrees very nearly with the deiinite \nproportions of 11 of carbon, 10 of oxygene, and 20 of \nhydrogene. \n\nAll the varieties of gum and mucilage are nutritious \nas food. They either partially or wholly lose their so- \nlubility in water by being exposed to a heat of 500\xc2\xb0 or \n600^ Fahrenheit, but their nutritive powers are not de- \nstroyed unless they are decomposed. Gum and muci- \nlage are employed in some of the arts, particularly in \ncalico-printing : till lately, in this country, the calico- \nprinters used gum arable; but many of them, at the sug- \ngestion of Lord Dundonald, now employ the mucilage \nfrom lichens. \n\n2. Starch is procured from different vegetables, but \nparticularly from Miieat or from potatoes. To make \nstarch from wheat, the grain is steeped in cold water till \nit becomes soft, and yields a milky juice by pressure ; \nit is then put into sacks of linen, and pressed in a vat \nfilled with water : as long as any milky juice exudes the \npressure is continued ; the fluid gradually becomes clear, \nand a white powder subsides Avhich is starch. \n\nStarch is soluble in boiling water, but not in cold wa- \nter, nor in spirits of wine. According to Dr. Thomson, \nit is a cliaracteristic property of starch to be solul)le in \na warm infusion of nutgalls, and to form a precipitate \nwhen the infusi(ui cools. \n\nStarch is more readily combustible than gum; when \n\n\n\nlUo Jl. \n\n\n\n\n\n57 \n\nthrown upon red hot iron, it burns with a kind of ex- \nplosion, and scarcely any residuum remains. Accord- \ning to Mr. Gay Lussac and Thenard, 100 parts of starch \nare composed of \n\nCarbon, with a small quau- ^ \n\ntity of saline and earthy V 43,55 \n\nmatter - * ~ 3 \n\nOxygene - - - 49,68 \nHydrogene - - - 6,7T \nor, \n\nCarbon - - - - \n\nOxygene and hydrogene in \n\nthe proportions necessary \n\nto form water \n\nSupposing this estimation correct, starch may be con- \nceived to be constituted by 15 proportions of carbon, \n13 of oxygene, and 26 of Iiydrogene. \n\nStarch forms a principal part of a number of escu- \nlent vegetable substances. Sowans, cassava, salop, sa- \ngo, all of them owe their nutritive powers principally \nto the starch they contain. \n\nStarch has been found in the following plants : \n\nBurdock {Arctium Lappa^) Deadly Nightshade {Jlt- \nropa Belladonna^) Bistort {Polygonum Bistorta,) WhiiQ \nBryony {Brijonia alba,) Meadow Saffron {Colcliicum \nautumiiale,) Dropwort {Spircea Filipendulay) Buttercup \n(Ranunculus bulbosiis,) Figvvort {Scrophularia nodosa^) \nDwarf Elder {Samhiicus Ebulus,) Common Elder \n(Sambuciis nigra.) Fool-stones [Orchis Morio,) Alex- \nanders {Imperatoria Ostriithium,) Henbane [Hijoscya- \nmus niger^ Broad-leaved Dock {Rumex obtusifolius,) \nSharp-pointed Dock {Rumex acutiis.) Water Dock. \n{Rumex aquaticus,) Wake Robin {Arum maculatum^) \nSalep {Orchis mascula,) Flower de luce or Water flag \n{Iris Pseudacorus) Stinkirig Gladwyn {Iris fmiidissi- \nma,) Earthnut {Bunium Bulbocastaniim.) \n\nii. Sugar in its purest state is prepared from the ex- \npressed juice of the Saccharum officinarmn, or sugar \ncane ; the acid in this juice is neutralized by lime, and \nthe sugar is crystallized by the evaporation of thcaque- \n\nH \n\n\n\n58 \n\nous parts of the juice, and slow-cooling : it is rendered \nwliite by the gradual filtration of water through\'it. In \nthe common process of manufacture, the whitening or \nrefining of sugar is only effected in a great length of \ntime ; the water being gradually suffered to percolate \nthrough a stratum of clay above the sugar. As the co- \nlouring matter of sugar is soluble in a saturated solu- \ntion of sugar, or syrup, it appears that refining may be \nmuch more rapidly and ceconomically performed by the \naction of syrup on coloured sugar.* The sensible pro- \nperties of sugar are well known. Its specific gravity, \naccording to Fahrenheit, is about 1.6. It is soluble in \nits own weight of water at 50\xc2\xb0 ; it is likewise soluble \nin alcohol, but in smaller proportions. \n\nLavoisier concluded from his experiments, that sugar \nconsists in 100 parts of \n\n28 carbon, \n\n8 hydrogene, \n64 oxygene. \nDr. Thompson considers 100 parts of sugar as com- \nposed of \n\n27,5 carbon, \n\n7,8 hydrogene, \n64,7 oxygene. \nAccording to the recent experiments of Gay Lussac \nand Thenard, sugar consists of 42,47 of carbon, and \n57,53 of water or its elements. \nLavoisier\'s and Dr. Thomson\'s analysis agree very \nnearly with the proportions of \n\n3 of carbon, \n\n4 of oxygene, \nand 8 of hydrogene. \n\n* A French gentleman lately in this country, stated to the West \nIndia planters, that he was in possession of a very expeditous and eco- \nnomical method of purifying and refining sugar, which he was willing \nto communicate to them for a very great pecuniary compensation. \nIlis terms were too high to be acceded to. Conversing on the sub- \nject wiih -Sir Joseph Banks, I mentioned to him, that I thought it \nprobable that raw sugar might be easily purified by passing syrup \nthrough it, which would dissolve the colouring matter. The same \nidea seems to have occurred about the same time, or before, to Ed- \nward Howard, Esq. who has since proved its efficacy experimentally, \nand has published an account of his process. \n\n\n\n59 \n\nGay Lussac\'s and Thenard\'s estimation gives the \nsame elements as in gum ; H of carbon, 10 of oxygene, \n20 of hydrogene. \n\nIt appears from the experiments of Proust, Achard, \nGoettling, and Parmentier, that there are many differ- \nent species of sugar ready formed in the vegetable king- \ndom. The sugar which most nearly resembles that of \nthe cane is extracted from the sap of the American ma- \nple, Acer Saccharinum. This sugar is used by the \nNorth American farmers, who procure it by a kind of \ndomestic manufacture. The trunk of the tree is bored \nearly in spring, to the depth of about two inches : a \nwooden spout is introduced into the hole ; the juice flows \nfor about five or six weeks. A common sized tree, that \nis, a tree from two to three feet in diameter, will yield \nabout 200 pints of sap, and every 40 pints of sap afford \nabout a pound of sugar. The sap is neutralized by \nlime, and deposits crystals of sugar by evaporation. \n\nThe sugar of grapes has been lately employed in \nFrance as a substitute for colonial sugar. It is procur- \ned from the juice of ripe grapes by evaporation, and the \naction of potashes ; it is less sweet than common sugar, \nand its taste is peculiar : it produces a sensation of cold \nwhile dissolving in the mouth ; and it is probable con- \ntains a larger proportion of water or its elements. \n\nThe roots of the beet {Beta vulgaris and cicla,) af- \nford a peculiar sugar, by boiling, and evaporation of the \nextract : it agrees in its general properties with the su- \ngar of grapes, but has a slightly bitter taste. \n\nManna, a substance which exudes from various trees, \nparticularly from the Fraxinus Ornus, a species of ash, \nwhich grows abundantly in Sicily and Calabria, may \nbe regarded as a variety of sugar, very analogous to the \nsugar of grapes. A substance analogous to manna has \nbeen extracted by Fourcroy and Vauquelin, from the \njuice of the common onion {Allium Cepa,) \n\nBesides the crystallized and solid sugars, there ap- \npears to be a sugar which cannot be separated from wa- \nter, and which exists only in a fluid form ; it constitutes \na principal part of molasses or treacle ; and it is found \nin a variety of fruits : and it is more soluble in alcohol \nthan solid sugar. \n\n\n\n(\\0 \n\nTIm\' siiiiplosi mode oi" deiecline; sugar is that rcconi \nluemlcd l).y JVlavi^raaf. The vegetable is to be boiled \nill a small quantity of alcohol; solid sugar, if any exist, \n"will separate during the cooling of the solution. \n\nSugar lias been extracted from the following vegeta- \nble supstauces : \n\nThe sap of the Birch (Betula alba,) of the Sycamore \n{Acer FsimdopJatanus^) of the Bamboo [Arundo Bam- \nboo.) of the Maize {yjea mays,) of the Cow Parsnip \n[UenuieuiiL SphmdijUum.,) of the Cocoa-nut tree [Co- \ncof) liucifcrtt^) oi\' the Walnut tree [Juglans alba,) of the \nAmerican Al(>e [A^ave mci\'icana,) of the Dulse [Fuciis \npatmatus,) of the Common Parsnip {Pastinicd sativa,) \nof St. John\'s J5read {Ceratonia Siliqua,) the fruit of \nthe (\\)mm()n Arbutus {Arbutoft Unedo,) and other sweet \nlasted fruits ; the roots of the turniji (Brassica Rapa,) \nof the (\'arrot {.Daucus Carota,) of Parsley [Apium pet- \nrnadinnn/,) the flower of tiu\' Euxine Khododendron \n[Rhododendron poiiticiniu) and from the nectarium of \nmost, other flowers. \n\nThe nutritive properties of sugar are well known. \nSince the British market has been over-stocked witli \nthis article from the West India islands, proposals have \nbeen made for applying it as the food of cattle ; experi- \nments have been made, which prove that they may be \nfattened by it; l)ut ditficulties connected with tiie duties \nlaid on sugar, have hitiierto prevented the plan from \nbeind tried to any extent. \n\n4. Albumen is a substance which has only lately been \ndiscovered in the vegetable kingdom, it abounds in \nthe juice of the papavv-tree [Caryca Papaya:) when \nthis juice is boiled, tlie albumen falls down in a coagu- \nlated state. It is likewise found in mushrooms, and in \nditlVvent species of funguses. \n\nAUiumen in its pure form, is a thick, glairy, tasteless \nfluid ; precisely the same as the white of tiie egg ; it is \n-soluble in cold water ; its solution, vvlien not too diluted. \nis coagulated by boiling, and the albumen separates in \nthe form of thin* flakes. Albumen is likewise coagula- \nted by acids and by alcohol : a solution of alhumen \ngives a precipitate when mixed with a cold solution of \nnut-galls. Albumen, when burnt, produces a smell of \n\n\n\n()1 \n\nvolatile alkali, and aflbrtls carbonic acid and water; it \nis therefore evidently principally composed of carbon, \nhydrogene, oxygenc, and azote. \n\nAccording to the experiments of Gay Lussac and \nThenard, 100 parts of albumen from the white of the \negg are composed of \n\nCarbon - - - - 52,883 \n\nOxygene - - - 23,872 \n\nHydrogene - - 7,540 \n\nAzote - - - 15,705 \n\nThis estimation would authorise the supposition, that \nalbumen is composed of 2 proportions of azote, 5 oxy- \ngene, 9 carbon, 22 hydrogene. \n\nThe principal part of the almond, and of the kernels \nof many other nuts, appears from the experiments of \nProust, to be a substance analogous to coagulated al- \nbumen. \n\nThe juice of the fruit of the ochra {Hibiscus esculen- \ntus,) according to Dr. Clarke, contains a li((uid albu- \nmen in such quantities, that it is employed in Domini- \nca as a substitute for the white of eggs in clarifying the \njuice of the sugar-cane. \n\nAlbumen may be distinguished from other substances \nby its property of coagulating by the action of heat or \nacids, when dissolved in water. According to Dr. Bos- \ntock, when the solution contains only one grain of albu- \nmen to 1000 grains of water, it becomes cloudy by ])c- \ning heated. \n\nAlbumen is a substance common to the animal as well \nas to the vegetable kingdom, and much more abundant \nin the former. \n\n5. Gluten may be obtained from wheaten flour by the \nfollowing process : the ilour is to be made into a paste, \nwhich is to be cautiously washed, by kneading it under \na small stream of water, till the water has carried oft\' \nfrom it all the starch ; what remains is gluten. It is a \ntenacious, ductile, elastic substance. It has no taste. \nBy exposure to air it becomes of a brown colour. It is \nvery slightly soluble in water; I)nt not soluble in alco- \nhol. When a solution of it in water is heated, the glu- \nten separates in tiie form of yellow flakes ; in tiiis res- \npect it agrees with albumen, but dift\'ers from it in being \ninfinitely less soluble in water, \'.riie solution of \'Aim- \n\n\n\n62 \n\nmen does not coagulate when it contains much less \nthan 1000 parts of albumen ; but it appears that gluten \nrequires more than 1000 parts of cold water for its so- \nlution. \n\nGluten, when burnt, affords similar products to albu- \nmen, and probably differs very little from it in composi- \ntion. Gluten is found in a great number of plants ; Proust \ndiscovered it in acorns, chesnuts, horse-chesnuts, apples, \nand quinces ; barley, rye, peas, and beans ; likewise in \nthe leaves of rue, cabbage, cresses, hemlock, borage, saf- \nfron, in the berries of the elder, and in the grape. Glu- \nten appears to be one of the most nutritive of the vege- \ntable substances ; and wheat seems to owe its superiori- \nty to other grain, from the circumstance of its contain- \ning it in larger quantities. \n\n6. Gmn elastic, or Caoutchouc^ is procured from the \njuice of a tree which grows in the Brazils, called Hse- \nvea. When the tree is punctured, a milky juice exudes \nfrom it, which gradually deposits a solid substance, and \nthis is gum elasic. \n\nGum elastic is pliable and soft like leather, and be- \ncomes softer when heated. In its pure state it is white ; \nits specific gravity is 9335. It is combustible, and burns \nwith a white flame, throwing off a dense smoke, with a \nvery disagreeable smell. It is insoluble in water, and \nin alcohol ; it is soluble in ether, volatile oils, and in \npetroleum, and may be procured from ether in an unal- \ntered state by evaporating its solution in that liquid. \nGum elastic seems to exist in a great variety of plants : \namongst them are, Jatropha elastica, Ficus indicaj Ar- \ntocarpus integrifolia, and Urceola elastica. \n\nBird-lime, a substance which may be procured from \nthe holly, is very analogious to gum elastic in its pro- \nperties. Species of gum elastic may be obtained from \nthe misletoe, from gum-mastic, opium, and from the ber- \nries of the Smilax caduca, in which last plant it has \nbeen lately discovered by Dr. Barton. \n\nGum elastic when distilled, affords volatile alkali, \nwater hydrogene, and carbon in different combinations. \nIt therefore consists principally of azote, hydrogene, \noxygene, and carbon ; but the proportions in which they \narc combined have not vet been ascertained. Gum elas- \n\n\n\n63 \n\ntic is an indigestible substance, not fitted for tlie food of \nanimals ; its uses in the arts are well known. \n\n7. Extract, or the extractive principle, exists in al- \nmost all plants. It may be procured in a state of tole- \nrable purity from saftron, by merely infusing it in water, \nand evaporating the solution. It may likewise be ob- \ntained from catechu, or Terra japonica, a substance \nbrought from India. This substance consists principal- \nly of astringent matter, and extract ; by the action of wa- \nter upon it, the astringent matter is first dissolved, and \nmay be separated from the extract. Extract is always \nmore or less coloured ; it is soluble in alcohol and water, \nbut not soluble in ether. It unites with alumina when \nthat earth is boiled in a solution of extract ; and it is \nprecipitated by the salts of alumina, and by many me- \ntallic solutions, particularly the solution of muriate of \ntin. \n\nFrom the products of its distillation, it seems to be \ncomposed principally of hydrogene, oxygene, carbon, \nand a little azote. \n\nThere appears to be almost as many varieties of ex- \ntract as there are species of plants. The diiFerence of \ntheir properties probably, in many cases, depends upon \ntheir being combined with small quantities of other ve- \ngetable principles, or to their containing different saline, \nalkaline, acid, or earthy ingredients. Many dyejing sub- \nstances seem to be of the nature of extractive principle, \nsuch as the red colouring matter of madder, and the yel- \nlow dye, procured from weld. \n\nExtract has a strong attraction for the fibres of cotton \nor linen, and combines with these substances when they \nare boiled in a solution of it. The combination is made \nstronger by the intervention of mordants, which are \nearthy or metallic combinations that unite to the cloth, \nand enable the colouring matter to adhere more strongly \nto its fibres. \n\nExtract in its pure form cannot be used as an article \nof food, but it is probably nutritive when united to starch, \nmucilage or sugar. \n\n8. Tannin, or the tanning principle, may be procured \nby the action of a small quantity of cold water on bruised \ngrape-seeds, or pounded gall-nuts ; and by the evapora \n\n\n\n64 \n\ntion of the solution to dryness. It appears as a yellow \nsubstance, possessed of a highly astringent taste. It is \ndiificiilt of combustion. It is very soluble both in wa- \nter and alcohol, but insoluble in ether. When a solu- \ntion of glue, or isinglass (gelatine,) is mixed with an \naqueous solution of tannin, the two substances, i. e. the \nanimal and vegetable matters fall down in combination, \nand form an insoluble precipitate. \n\nWhen tannin is distilled in close vessels, the princi- \nj)al products are charcoal, carbonic acid, and inflamma- \nble gases, with a minute quantity of volatile alkali. \nHence its elements seem the same as those of extract, \nbut probably in different proportions. The characteris- \ntic property of tannin is its action upon solutions of isin- \nglass or jelly; this particularly distinguishes it from ex- \ntract, with which it agrees in most other chemical qua- \nlities. \n\nThere are many varieties of tannin, which probably \nowe the difference of their properties to combinations \nwith other principles, especially extract, from which it \nis not easy to free tannin. The purest species of tannin \nis that obtained from the seeds of the grape ; this forms \na white precipitate, with solution of isinglass. The tan- \nnin from gall-nuts resembles it in its properties. That \nfrom sumach affords a yellow precipitate ; that from ki- \nno a rose coloured ; that from catechu a fawn coloured \none. The colouring matter of Brazil wood, which M. \nChevreul considers as a peculiar principle, and which he \nhas called Hematine, differs from other species of tan- \nnin, in affording a precipitate with gelatine, which is so- \nluble in abundance of hot water. Its taste is much \nsweeter than that of the other varieties of tannin, and it \nmay, perhaps, be regarded as a substance intermediate \nbetween tannin and extract. \n\nTannin is not a nutritive substance, but is of great im- \nportance in its application to the art of tanning. Skin \nconsists almost entirely of jelly qy gelatine, in an organi- \nzed state, and is soluble by the long continued action of \nhoiling water. When skin is exposed to solutions con- \ntaining tannin, it slowly combines with that principle ; \nits fibrous texture and coherence are preserved : it is \nrendered perfectly insoluble in water, and is no longer \n\n\n\np. 64 \n\n\n\nFiq. 12. \n\n\n\n\n65 \n\nliable to putrefaction : in short, it becomes a substance \nin chemical composition precisely analogous to that \nfurnished by tlie solution of jelly and the solution of \ntannin. \n\nIn general, in this country, the bark of the oak is used \nfor affording tannin in tlie manufacture of leather ; but \nthe barks of some other trees, particularly the Spanish \nchesnut, have lately come into use. The following ta- \nble will give a general idea of the relative value of dif- \nferent species of barks. It is founded on the result of \nexperiments made by myself. \n\nTable of *N*iimhers exhibiting the quantify of Tannin \nafforded by 480lbs. of different Barlcs, which express \nnearly their relative Values. \n\n\n\nAverage of entire bark of middle-sized Oak, cut in \n\nspring \n\nof Spanish Chesnut \n\n\xe2\x80\x94 \xe2\x80\x94 of Leicester Willow, large \n\nsize \n\nof Elm \n\n\'. of Common Willow, large \n\nof Ash \n\nof Beech - - - \n\nof Horse Chesnut \n\nof Sycamore \n\nof Lonibardy Poplar - \n\nof Birch - - \n\nof Hazel - - - \n\nof Black Thorn \n\nof Coppice Oak \n\n\' \xe2\x80\xa2 of Oak cut in autumn \n\nof Larcli cut in autumn \n\nWhite interior cortical layers of Oak Bark \n\n\n\n29 \n21 \n\n33 \n13 \n11 \n16 \n10 \n\n9 \n11 \n15 \n\n8 \n14 \n16 \n32 \n21 \n\n8 \n72 \n\n\n\nThe quantity of the tanning principle in barks dif- \nfers in different seasons ; when the spring has been very \ncold the quantity is smallest. On an average, four or \nfive pounds of good oak bark arc required to form one \npound of leather. The inner cortical layers in all barks \ncontain tlie largest quantity of tannin. Barks contain \n\nr \n\n\n\n66 \n\nthe greatest proportion of taimiu at the time the buds \nbegin to open \xe2\x80\x94 the smallest quantity in winter. \n\nThe extractive or colouring matters found in barks, \nor in substances used in tanning, influence the quality \nof leather. Thus skin tanned with gall-nuts is much \npaler than skin tanned with oak bark, which contains \na brown extractive matter. Leather made from catechu \nis of a reddish tint. It is probable that in the process \nof tanning, the matter of skin, and the tanning princi- \nple first enter into union, and that the leather at the mo- \nment of its formation unites to the extractive matter. \n\nIn general, skins in being converted into leather in- \ncrease in weight about one third ;* and the operation is \nmost perfect when they are tanned slowly. When skins \nare introduced into very strong infusions of tannin, the \nexterior parts immediately combine with that principle, \nand defend the interior parts from the action of the so- \nlution ; such leather is liable to crack and to decay by \nthe action of water. \n\nThe precipitates obtained from infusions containing \ntannin by isinglass, when dried, contain at a medium \nrate about 40 per cent, of vegetable matter. It is easy \nto obtain the comparative value of different substances \nfor the use of the tanner, by comparing the quantities \nof precipitate afforded by infusions of given weights \nmixed with solutions of glue or isinglass. \n\nTo make experiments of this kind, an ounce or 480 \ngrains of the vegetable substance in coarse powder, \nshould be acted upon by half a pint of boiling water. \nThe mixture should be frequently stirred, and suffered \nto stand 24 hours ; the fluid should then be passed through \na fine )inen cloth and- mixed with an equal quantity of \nsolution of gelatine, made by dissolving glue, jelly, or \nisinglass in hot water, in the proportion of a drachm of \nglue or isinglass, or six table spoonfuls of jelly, to a \npint of water. \'Vha precipitate should be collected by \npassing the mixture of the solution and infusion through \nfolds of blotting paper ; and the paper exposed to the \nair till its contents are quite dry. If pieces of paper \n\n* Tliis estimation must be considered as applying to dry skin and \n.-/rv leather. \n\n\n\n67 \n\nof equal weights are used, in cases iu Avhich different \nvegetable substances are employed, the ditlerence of the \nweights of the papers when dried, will indicate with \ntolerable accuracy, the quantities of tannin contained by \nthe substances, and their relative value, for the purposes \nof manufacture. Four tenths of the increase of weight, \nin grains, must be taken, which will be in relation to \nthe weights in the table. \n\nBesides the barks already mentioned, there are a num- \nber of others which contain the tanning principle. Few \nbarks indeed are entirely free from it. It is likewise \nfound in the wood and leaves of a number of trees and \nshrubs, and is one of the most generally diffused of the \nvegetable principles. \n\nA substance very similar to tannin has been formed \nby Mr. Hatchett, by the action of heated diluted nitric \nacid on charcoal, and evaporation of the mixture to \ndryness. From 100 grains of charcoal Mr. Hatchett \nobtained 120 grains of artificial tannin, which, like na- \ntural tannin, possessed the property of rendering skin \ninsoluble in vi^ater. \n\nBoth natural and artificial tannin form compounds \nwith the alkalies and the alkaline earths ; antl these \ncompounds are not decomposable by skin. The attempts \nthat have been made to render oak bark more efficient \nas a tanning material by infusion in lime water, are con- \nsequently founded on erroneous principles. Lime forms \nwith tannin, a compound not soluble in water. \n\nThe acids unite to tannin, and produce compounds \nthat are more or less soluble in water. It is probable \nthat in some vegetable substances tannin exists, combi- \nned with alkaline or earthy matter; and such substan- \nces will be rendered more efficacious for the use of the \ntanner, by the action of diluted acids. \n\n9. Indigo may be procured from woad [Tsatis tincto- \nria,) by digesting alcohol on it, and evaporating the so- \nlution. White crystalline grains are obtained, which \ngradually become blue by the action of the atmosphere : \nthese grains are the substance in question. \n\nThe indigo of commerce is principally brought from \nAmerica. It is procured from the Indigofera argenteUy \nor wild indigo, the Indigofera disperma, or Gautimala \n\n\n\nindigo, ami the liidigofera tinctoria, or French indigo. \nIt is prepared by fermenting the leaves of those trees \nin water. Indigo in its common form appears as a fine, \ndeep blue powder. It is insoluble in water, and but \nslightly soluble in alcohol: its true solvent is sulphuric \nacid : eight parts of sulphuric acid dissolve one part of \nindigo ; and tlie solution diluted with water forms a \nvery line blue dye. \n\nIndigo, by its distillation, affords carbonic acid gas, \nwater, charcoal, ammonia, and some oily and acid mat- \nter : tlie charcoal is in very large proportion. Pure in- \ndigo therefore most probably consists of carbon, hydro- \ngene, oxygene, and azote. \n\nIiidigo owes its blue colour to combination with oxy- \ngene. For the uses of the dyers it is partly deprived \nof oxygene, by digesting it with orpiment and lime wa- \nter, when it becomes soluble in the lime water, and of \na greenish colour. Cloths steeped in this solution com- \nbine with the indigo ; they are green when taken out of \nthe liquor, but become blue by absorbing oxygene when \nexposed to air. \n\nIndigo is one of the most valuable and most extensive- \nly used of the dyeing materials. \n\n10. The narcotic principle is found abundantly in \nopzM?/?, which is obtained fi\'om the juice of the white pop- \npy [Papaver album.) To procure the narcotic principle, \nAvater is digested upon opium: the solution obtained is \nevaporated till it becomes of the consistence of a syrup. \nBy the addition of cold water to this syrup a precipitate \nis obtained. Alcohol is boiled on this precipitate ; du- \nring the cooling of the alcohol crystals fall down. These \ncrystals are to be again dissolved in alcohol, and again \nprecipitated by cooling : and the process is to be repeat- \ned till their colour is white; they are crystals of narco- \ntic principle. \n\nThe narcotic principle has no taste nor smell. It is \nsoluble in about 400 parts of boiling water; it is insolu- \nble in cold water : it is soluble in 24 parts of boiling \nalcohol, and in 100 parts of cold alcohol. J t is very \nsoluble in all acid menstrua. \n\nIt has been shewn by De Rosne, that the action of \nopium on the animal economy depends on this principle.. \n\n\n\n69 \n\nMany other substances besides the juice of the poppy, \npossess narcotic properties ; but they have not yet been \nexamined with much attention. The Lactuta sativa, \nor garden lettuce, and most of the other lactucas yield \na milky juice, which when inspissated has the charac- \nters of opium, and probably contains the same narcotic \nprinciple. \n\n11. The hitter \'principle is very extensively diffused \nin the vegetable kingdom ; it is found abundantly in the \nhop [Humilus lupilus,) in the common broom [Spartium \nscoparium,) in the chamomile [Anthemis nobilis,) and in \nquassia, amara and excelsa. It is obtained from those \nsubstances by the action of water or alcohol, and eva- \nporation. It is usually of pale yellow colour ; its taste \nis intensely bitter. It is very soluble, both in water and \nalcohol ; and has little or no action on alkaline, acid, \nsaline, or metallic solution. \n\nAn artificial substance, similar to the bitter principle, \nhas been obtained by digesting diluted nitric acid, on \nsilk, indigo, and the wood of the white willow. This \nsubstance has the property of dyeing cloth of a bright \nyellow colour ; it differs from the natural bitter princi- \nple in its power of combining with the alkalies : in \nunion with the fixed alkalies it constitutes crystallized \nbodies, which have the property of detonating by heat \nor percussion. \n\nThe natural bitter principle is of great importance in \nthe art of brewing; it checks fermentation, and pre- \nserves fermented liquors; it is likewise used in medicine. \n\nThe bitter principle, like the narcotic principle, ap- \npears to consist principally of carbon, hydrogene and \noxygene, with a little azote. \n\n12. Wax is found in a number of vegetables ; it is \nprocured in abundance from the berries of the wax myr- \ntle [Myrica cerifera:) it may be likewise obtained from \nthe leaves of many trees; in its pure state it is white. Its \nspecific gravity is 9,662 ; it melts at 155 degrees ; it is \ndissolved by boiling alcohol ; but it is not acted upon by \ncold alcohol ; it is insoluble in water ; its properties as \na combustible body are well known. \n\nThe wax of the vegetal)le kingdom seems to be pre- \nriselvof the same nature as that afforded bv the bee. \n\n\n\nFrom the experiments of M. M. Gray Lusf^ac and The- \nnard, it appears that 100 parts of wax consist of , \n\nCarbon - - - - 81,784 \nOxygene - - \' - - 5,544 \n\nHydrogene - - - 12,672 \n\nOr otherwise, \n\nCarbon .... 81,784 \nOxygene and hydrogene in the ^ \n\nproportions necessary to form \\ 6,300 \n\nwater ... ^ \n\nHydrogene - - - 11,916 \n\nwhich agrees very nearly with 37 proportions of hydro- \ngene, 21 of charcoal, one of oxygene. \n\n13. Resin is very common in the vegetable kingdom. \nOne of the most usual species is that aftbrded by the dif- \nferent kinds of fir. When a portion of the bark is re- \nmoved from a fir tree in spring, a matter exudes, which \nis called turpentine ; by heating this tui-pentine gently, \na volatile oil rises from it, and a more fixed substance \nremains, this substance is resin. \n\nThe resin of the fir is the substance commonly known \nby the name of rosin ; its properties are well known. \nIts specific gravity is 1072. It melts readily, burns \nwitli a yellow light, throwing off much smoke. Resin \nis insoluble in water, either hot or cold ; but very solu- \nble in alcohol. When a solution of resin in alcohol is \nmixed with water, the solution becomes milky ; the re- \nsin is deposited by the stronger attraction of the water \nfor the alcohol. \n\nResins are obtained from many other species of trees. \nMastich, from the Fistachia lentiscus. Elemi from the \nAmyris elemifera, Copal from the Rhus copallinum, San- \ndarach from the common juniper. Of these resins copal \nis the most peculiar. It is the most difficultly dissolved \nin alcohol ; and for this purpose must be exposed to that \nsubstance in vapour; or the alcohol employed must hold \ncamphor in solution. Accordins; to Gray Lussac and \nThenard, \n\n\n\nrt \n\n\n\n100 parts of cotiimou resin contain \n\n\n\n\nCarbon \n\n\n- \n\n\n- \n\n\n75,944 \n\n\nOxygene - \n\n\n- \xe2\x96\xa0 \n\n\n- \n\n\n13,337 \n\n\nHydrogene \n\n\n- \n\n\n- \n\n\n10,719 \n\n\nor of \n\n\n\n\n\n\n\n\nCarbon \n\n\n- \n\n\n- \n\n\n75,944 \n\n\nOxygene and \n\n\nhydrogene in \n\n\nthe) \n\n\n\n\nproportions \n\n\nnecessary to form } \n\n\n15,156 \n\n\nwater \n\n\n- \n\n\n) \n\n\n\n\nHydrogene in \n\n\nexcess \n\n\n\n\n8,900 * \n\n\nAccording to the same cliemists, \n\n\n100 \n\n\nparts of copal \n\n\nconsist of \n\n\n\n\n\n\n\n\nCarbon \n\n\n- \n\n\n- \n\n\n76,811 \n\n\nOxygene \n\n\n- \n\n\n- \n\n\n10,606 \n\n\nHydrogene \n\n\n- \n\n\n- \n\n\n12,583 \n\n\n01, \n\nCarbon \n\n\n- \n\n\n- \n\n\n76,811 \n\n\nWater or its elements \n\n\n- \n\n\n12,052 \n\n\nHydrogene \n\n\n- \n\n\n- \n\n\n11,137 \n\n\n\nFrom these results if resin be a definite compound, it \nmay be supposed to consist of eight proportions of car- \nbon, twelve of hydrogene, and one of oxygene. \n\nResins are used for a variety of purposes. Tar and \npitch principally consist of resin, in a partially decom- \nposed state. Tar is made by the slow combustion of the \nfir 5 and pitch by the evaporation of the more volatile \nparts of tar. Kesins are employed as varnish, and for \nthese purposes are dissolved in alcohol or oils. Copal \nforms one of the finest. It may be made by boiling it \nin powder with oil of rosemary, and tlien adding alco- \nhol to the solution. \n\n14. Camphor is procured by distilling the wood of the \ncamphor tree ( Laiirus camplwra,) which grows in Ja- \npan. It is a very volatile body, and may be purified \nby distillation. Camphor is a white, brittle, semitrans- \nparent substance, having a peculiar odour, and a strong \nacrid taste. It is very slightly soluble in water ; more \nthan 100,000 parts of water arc required to dissolve one \npai\'t of camphor. It is very soluble in alcohol ; and by \nadding water in small quantities at a time to the solu- \ntion of camphor in alcohol, the camphor separates in a \n\n\n\ncrystallized i\'onu. It is soluble in nitric acid, and is se- \nparated IVoiu it by water. \n\nCainplior is very inllanunabic ; it burns witli a bris;ht \nflame, autl tlirows olV a j;Teat quantity of carbonaceous \nmatter. It forms in combustion water, carbonic acid, \nand a peculiar acid called ciuuplioric acid. No accur \nrate analysis has been made of campbcu-, but it st^.ems to \napproach to the resins in its composition ; and consists of \ncarbou, bydroj;\'eue, aud oxysjene. \n\nCamphor exists in other plants besides the Lauims \ncamjjltora. It is procured from sjiecies of the laurus \nj;ro\\viu:i;* in Sumatra, Horneo, and other of the Kast \nIndian isles. It has been obtained from thyme {Thy- \nmus scv^iUnnu[ nuirjorum [Origanum majorana,) Gin- \np;er tree [Jlmmuntn Zingiber y) Saa;e [Salvia afficlna- \n//.s\'.) Many volatile oils yield camphor by being mere- \nly exposed to the air. \n\nAn artificial substance very similar to camphor has \nbeen iVuined by M. Kind, by saturating; oil of turpen- \ntine with muriatic acid gas (the gaseous substance pro- \ncured from connuon salt by the action of sulphuric \nacid.) The cami)hor procured in well conducted ex- \n])eriments amounts to half of the oil of turj)entine used. \nIt agrees with common camphor in most of its sensible \nj\xc2\xbbroperties ; but ditl\'ers materially in its chemical (puili- \nties aud composition. It is not soluble without decom- \nposition in nitric acid. From the experiments of Geh- \nlen, it appears to consist of the elements of oil of tur- \npentine, carbon, hydrogene and oxygene, united to the \nelements of nuniatic gas, chlorine aud hydrogene. \n\nFrom the analogy of artilicial to natural camphor, it \ndoes not appear improbable, that natural cami)hor may \nbe a secondary vegetable compound, consisting of cam- \nphoric acid ami volatile oil. Camphor is used medici- \nnally, but it has no other application. \n\n15. Fidrd oil is obtained by expression from seeds \nand fruits: the olive, the almond, linseed and rape-seed \natVord the nu)st common vegetable fixed oils. The pro- \nperties of fixed oils are well known. Their specific \ngravity is less than that of w ater ; that of olive and of \nrape-seed oil is 91o; that of linseed and almond oil 932; \nthat of palm oil 9t>8 : that of walnut aud beech mast oil \n\n\n\n73 \n\n923. Many of the fixed oils congeal at a lower lem|)e- \nrature tiian tliat at which water freezes. They all require \nfor tlieir eva|)oration a hii;lier temperature tliari that at \nwhich water l)oils. The [iroducts of tlie combustion of \noil are water, and carbonic acid i;as. \n\nFrom the exj)erimcnts of (jiay Lussac and Thenard, it \nappears tiiat olive oil contains in 100 parts, \n\nCarbon - - 77,213 \n\nOxygenc - - 9,427 \n\nHydrogenc - - 13,360 \n\nThis estimation is a near aproximation to 11 propor- \ntions of carbon, 20 hydrogene, and one oxyjjjenc;. \n\nThe following is a list of fixed oils, and of the trees \nthat aflord them. \n\nOlive oil, from the Olive tree {Olea Europea,) Lin- \nseed oil, from the common and Perennial Flax [Linum \n2isitatisitimum et percnne,) Nut oil, from the lla/el nut \n[Covyllus avellana,) Walnut, [Jui^lans regia,) Hemp \noil, from the Hemp [Cannahis sativay) Almond oil from \nthe sweet Almond, (Jlmy/^\'duhis communisy) Heech oil, \nfrom the common Beech [Fai^us sylvatica^) Rape-seed \noil, from the Rapes {^BrasHica najms et campeatriH,) Pop- \npy oil, from the Poppy [PapavGv aomnifcvum,) oil of \nSesamum, from the Sesamum (Seftamum orientate,) \nCucumber oil, from the Gourds [CucuThita pepo etma- \nleppo,) oil of Mustard, from the Mustard [Sinaph ni- \ngra et arvensin,) oil of Sunflower, from the annual and \nperennial Sunflower, [Jlelianflius annuus et perennis,) \nCastor Oil, from the Palma Christi [Ricinun commu- \nnis,) Tobacco-seed oil, from the Tobacco {J^Ticotiana \nfabacum et rustica,) Plum kernel oil, from the Plum \ntree {Prunus domeHtica,) (Irape-seed oil, from the Vine \n( Vitia vinifera,) Rutter of cacoa, from tli(5 Cacoa tree \n[Theobroma cacao,) Laurel oil, from the sweet Ray tree \n[Lauras nobilis,) \n\nThe fixed oils are very nutritive substances; they are, \nof great importance in their applications to the purposes \nof life. Fixed oil, in combination with soda, forms the \nfinest kind of hard soap. The fixed oils are used ex- \ntensively in tlnMiiiM hani(;al arts, and for the preparati<m \nof pigments and varnishes. \n\nIG. J\'ulaUhi oil, likewise calhid essenliul ail. diflers \n\nK \n\n\n\n74 \n\nfrom fixed oil, in being capable of evaporation by a much \nlower <U\'i:;rec of lieat ; in being soluble in alcohol, and \nin possessing a very slight degree of solubility in wa- \nter. \n\nThere is a great number of volatile oils, distinguish- \ned by their smell, their taste, their specific gravity, and \nother sensible qualities. A strong and peculiar odour \nmay however be considered as the great characteristic of \neach species ; the volatile oils inflame with more facility \nthan the fixed oils, and afford by their combustion dif- \nferent proportions of the same substances, water, car- \nbonic acid, and carbon. \n\nThe following specific gravities of different \\olatile \noils were ascertained by Dr. Lewis. \n\nOil of Sassafras - - - 1094 \n\nCinnamon - - - 1035 \n\nCloves ... . 1034 \n\nFennel - - - 997 \n\nDill . - . . 994 \n\nPenny Royal - - 978 \n\nCummin - - - 975 \n\nMint - - - - 975 \n\nNutmegs - - - 948 \n\nTansy - - - 946 \n\nCarraway - - - 940 \n\nOriganum - - - 940 \n\nSpike - - - - 936 \n\nRosemary - - - 934 \n\nJuniper - - - 911 \n\nOranges - - - 888 \n\nTurpentine - - - 792 \n\nThe peculiar odours of plants seem, in almost all ca- \nses, to depend upon the peculiar volatile oils they con- \ntain. All the perfumed distilled waters owe their pe- \nculiar properties to the volatile oils they hold in solu- \ntion. By collecting the aromatic oils, the fragrance of \nflowers, so fugitive in the common course of nature, is \nas it were embodied and made permanent. \n\nIt cannot be doubted that the volatile oils consist of \ncarbon, hydrogene, and o\\y;;ene ; but no accurate ex- \n\n\n\n75 \n\nj)erinieiits have as yet been made on the proportions in \nwhich these elements are combined. \n\nThe volatile oils have never been used as articles ol* \nfood ; many of them are employed in the arts, in the \nmanufacture of pii^ments and varnishes ; but their most \nextensive application is as perfumes. \n\n17. Woody fibre is procured from the wood, bark, \nleaves, or flowers of trees, by exposing them to the re. \npeated action of boiling water and boiling alcohol. It \nis the insoluble matter that remains, and is the basis of \nthe solid organized parts of plants. There are as ma- \nny varieties of woody fibre as there are plants and or- \ngans of plants ; but they are all distinguished by their \nfibrous- texture, and their insolubility. \n\nWoody fibre burns with a yellow flame, and produces \nwater and carbonic acid in burning. When it is distil- \nled in close vessels, it yields a considerable risiduum of \ncharcoal. It is from woody fibre, indeed, that charcoal \nis procured for the purposes of life. \n\nThe following table contains the results of experi- \nments made by Mr. Mushet, on the quantity of charcoal \naiforded by difi*erent wood. \n\n100 parts of Lignum Vitae - 26,8 of charcoal \n\nMahogany - 2.5,4 \n\n\xe2\x96\xa0 Laburnum - 24,5 \n\nChesnut - - 23,2 \n\n~ Oak - - - 22,6 \n\nAmerican black \n\nBeech - - 21,4 \n\nWalnut - - 20,6 \n\nHolly - \' - 19,9 \n\nBeech - - 19,9 \n\nAmerican Maple 19,9 \n\nElm - - 19,5 \n\nNorway Pine - 19,2 \n\nSallow - - 18,4 \n\nAsh - - 17,9 \n\nBirch - - 17,4 \n\nScottish Fir - 16,4 \n\nM. Gay Lussac and Thenard have concluded from \n\n\n\nHioii\' experiments on the wood of the oak and the beech, \nthat 100 parts of the first contain : \n\n\n\nOf Carbon \n\n\xe2\x80\x94 Oxygenc \n\n\xe2\x80\x94 Hydrogcne \n\n\n52,53 \n\n41,78 \n\n5,69 \n\n\n\xe2\x80\xa2ts of the second : \n\n\n\n\nOf Carbon \n\n\xe2\x80\x94 Oxyi^enc \n\n\xe2\x80\x94 Hydrogcne \n\n\n51,45 \n42,7.5 \n\n5,82 \n\n\n\nSnpposing woody fibre to be a definite compound, \ntliese estimations lead to the conclusion, tlnit it consists \n(\xc2\xbbf five proportions of carbon, tin-ec of oxygene, and six \nof hydrogcne ; or 57 carbon, 45 oxygene, and six hy- \ndrogcne. \n\nIt w ill be unnecessary to speak of the applications of \nAvoody fibre. The diflerent uses of the woods, cotton, \nlinen, the barks of trees are sufficiently known. Woody \nfibre appears to be an indigestible substance. \n\n18. Tlie acids found in the vegetable kingdom are \nnumerous ; the true vegetable acids which exist ready \nformed in the juices or organs of plants, are the oxalic, \ncitric, tartaric, benzoic, acetic, malic, gallic, and prus- \nsic acid. \n\nAll these acids, except the acetic, malic, and prussic \nacids, are white crystallized bodies. The acetic, malic, \nand prussic acids liave been obtained only in the fluid \nstate ; they are all more or less soluble in water ; all \nhave a sour taste except the gallic and prussic acids ; \nof which the first has an astringent taste, and the latter \na taste like that of bitter almonds. \n\nThe oxalic acids exists, uncombined, in the liquor \nwhich exudes from the Chich pea [Cicer arietinunu) \nand may be procured from wood sorrel ( O.valis acetosel- \nla,) common sorrel, and other species of Uumex ; and \nfrom the Geranium acidum. Oxalic acid is easily dis- \ncovered and distinguished from other acids by its pro- \nperty of decomposing all calcareous salts, and forming \nwith lime a salt insoluble in water ; and by its crystal- \nlizing in fouT-sided prisms. \n\n\n\nTiie citric acid is the peculiar acid existing in the \njuice of lemons and oranges. It may likwLse be obtain- \ned from the cranbery, whortleberry, and hip. \n\nCitric acid is distinguished by its forming a salt inso- \nluble in water with lime ; but decomposable by the mi- \nneral acids. \n\nThe tartaric acid may be obtained from the juice of \nmulberries and grapes ; and likewise from the pulp of \n<he tamarind. It is characterised by its property of \nforming a difficultly soluble salt with potassa, and an \ninsoluble salt decomposable by the mineral acids with \nlime. \n\nBenzoic acid may be procured from several resinous \nsubstances by distillation ; from benzoin, storax, and \nbalsam of Tolu. It is distinguished from the other \nacids by its aromatic odour, and by its extreme vola- \ntility. \n\nMalic acid maybe obtained from the juice of apples, \nbarberries, plums, elderberries, currants, strawberries, \nand raspberries. It forms a soluble salt with lime; and \nis easily distinguished by this test from the acids alrea- \ndy named. \n\nAcetic acid, or vinegar, may be obtained from the \nsap of different trees. It is distinguished from malic \nacid by its peculiar odour ; and from the other vegeta- \nble acids by forming soluble salts with the alkalies and \nearths. \n\nGallic acid may be obtained by gently and gradually \nheating powdered gall-nuts, and receiving the volatile \nmatter in a cool vessel. A number of white crystals \nwill appear, which are distinguished by their property \nof rendering solutions of iron, deep purple. \n\nThe vegetable prussic acid is procured by distilling \nlaurel leaves, or the kernels of the peach, and cherry, \nor bitter almonds. It is characterized by its property \nof forming a blueish green precipitate, when a little al- \nkali is added to it, and it is poured into solutions con- \ntaining iron. It is very analogous in its properties to \nthe prussic acid obtained from animal substances ; or by \npassing ammonia over heated charcoal ; but tliis last \nbody forms, with the red oxide of iron, tlie deep, bright \nblue substance, called Prussian blue. \n\n\n\n7-8 \n\nTwo other vegetable acids have been found in the \nproducts of plants ; the morolyxic acid in a saline exu- \ndation from the white mulberry tree, and the kinic acid \nin a salt afforded by Peruvian bark; but these two \nbodies have as yet been discovered in no other cases. \nThe phosphoric acid is found free in the onion ; and the \nphosphoric, sulphuric, muriatic, and nitric acids, exist \nin many saline compounds in the vegetable kingdom ; \nbut they cannot with propriety be considered as vegata- \nble products. Other acids are produced during the com- \nbustion of vegetable compounds, or by the action of ni- \ntric acid upon them ; they are the camphoric acid, the \nmucous or saclactic acid, and the suberic acid ; the first \nof which is procured from camphor ; the second from \ngum or mucilage; and the third from cork,by the action \nof nitric acid. \n\nFrom the experiments that have been made upon the \nvegetable acids, it appears that all of them, except the \nprussic acid, are constituted by different proportions of \ncarbon, hydrogene, and oxygene ; the prussic acid con- \nsists of carbon, azote, and hydrogene, with a little oxy- \ngene. The gallic acid contains more carbon than any \nof the other vegetable acids. \n\nThe following estimates of the composition of some \nof the vegetable acids have been made by Gay Lussac \nand Thenard. \n\n100 parts of oxalic acid contain : \n\nCarbon - - 26,566 \nHydrogene - 2,745 \n\n\n\nOxygene - - \n\n\n70,689 \n\n\nDitto of Tartaric acid: \n\n\n\n\nCarbon - - \n\n\n24,050 \n\n\nHydrogene - \n\n\n6,629 \n\n\nOxygene - - \n\n\n69,321 \n\n\nDitto citric acid : \n\n\n\n\nCarbon - - \n\n\n33,811 \n\n\nHydrogene - \n\n\n6,330 \n\n\nOxygene - - \n\n\n59,859 \n\n\nDitto acetic acid : \n\n\n\n\nCarbon - - \n\n\n50,224 \n\n\nHydrogene - \n\n\n5,629 \n\n\nOxygene - - \n\n\n44.147 \n\n\n\n79 \n\n100 parts of mucous or saclactic acid : \nCarbon - - 33,69 \nHytlrogene - - 3,62 \nOxygene - 62,69 \n\nThese estimations agree \'\xe2\x80\xa2nearly with the following de- \nfinite proportions. In oxalic acid 7 proportions of car- \nbon, 8 of hydrogene, and 15 of oxygene ;* in citric \nacid, 8 carbon, 28 hydrogene, 18 oxygene; in acetic \nacid, 3 carbon, 6 hydrogene, 4 oxygene; in acetic acid, \n18 carbon, 22 hydrogene, 12 oxygene ; in mucous acid, \n6 corbon, 7 hydrogene, 8 oxygene. \n\nThe applications of the vegetable acids are well \nknown. The acetic and citric acids are extensively used. \nThe agreeable taste and wholesomeness of various ve- \ngetable substances used as food, materially depend up- \non the vegetable acid they contain. \n\n19. Fixed alkali may be obtained in acqueous solu- \ntion from most plants by burning them, and treating the \nashes with quick lime and watei*. The vegetable alkali, \nor potassa, is the common alkali in the vegetable king- \ndom. This substance in its pure state is white, and \nsemi-transparent, requiring a strong lieat for its fusion, \nand possessed of a highly caustic taste. In the matter \nusually called pure potassa by chemists, it exists com- \nbined with water, and in that commonly called pearl \nashes, or potashes in commerce, it is combined with a \nsmall quantity of carbonic acid. Potassa in its uncora- \nbined state, as has been mentioned, page 89, consists of \nthe highly inflammable metal potassium, and oxygene, \none proportion of each. \n\nSoda,, or the mineral alkali, is found in some plants \nthat grow near the sea ; and is obtained combined with \nwater, or carbonic acid, in the same manner as potassa ; \nand consists, as has been stated, page 39, of one pro- \nportion of sodium, and two proportions of oxygene. \nIn its properties it is very similar to potassa : but may \nbe easily distinguished from it by this character : it forms \na hard soap with oil : potassa forms a soft soap. \n\n* Accordinj^ to Dr. Thomson\'s experiments, oxalic acid consists of \n3 proportions of carbon, 4 of oxyt^ene, and 4 of liydrogene., a rchul!: \n"cry different indeed from that of the French chemists. \n\n\n\n80 \n\nPearl ashes, and barilla and kelp, or the impure soda \nobtained from the ashes of marine plants, are very va- \nluable in commerce, principally on account of their \nuses in the manufacture of glass and soap. Glass is \nmade from fixed alkali, flint, and certain metallic sub- \nstances. \n\nTo know whether a vegetable yields alkali, it should \nbe burnt, and the ashes washed with a small quantity \nof water. If the water, after being for some time ex- \nposed to the air, reddens paper tinged with turmeric : \nor renders vegetable blues, green, it contains alkali. \n\nTo ascertain the relative quantities of pot-ashes af- \nforded by difi\'erent plants, equal weights of them should \nbe burnt : the ashes washed in twice their volume of \nwater ; the washings should be passed through blotting \npaper and evaporated to dryness : the relative weights \nof the salt obtained will indicate very nearly the rela- \ntive quantities of alkali they contain. \n\nThe value of marine plants in producing soda, may \nbe estimated in the same manner, with sufficient correct- \nness for all commercial purposes. \n\nHerbs, in general, furnish four or five times, and \nshrubs two or three times as much pot-ashes as trees. \nThe leaves produce more than the branches, and the \nbranches more than the trunk. Vegetables burnt in a \ngreen state produce more ashes than in a dry state. \n\nThe following table* contains a statement of the quan- \ntity of pot-ashes afforded by some common trees and \nplants. \n\n10,000 parts of Oak . - - 15 \n\nof Elm - - - 39 \n\nof Beech - - 12 \n\nof Vine - - 55 \n\nof Poplar - - 7 \n\nof Thistle - - 53 \n\nof Fern - - - 62 \n\nof Cow Thistle 196 \n\nof WormAvood 730 \n\n\xe2\x80\x94 of Vetches - - 275 \n\n* It is founded upon the experiments of Kirwan, Vauquelin, and \nPcitiiis. \n\n\n\n81 \n\n10,000 parts of Beans - - 200 \nof Fumitory - 790 \n\nThe eqrths found in plants are four : silica or ilie \nearth of flints, alumina or pure clay, lime, and magne- \nsia. They are procured by incineration. The lime is \nusually combined with carbonic acid. This substance \nand silica are much more common in the vegetable king- \ndom than magnesia, and magnesia more common than \nalumina. The earths form a principal part of the mat- \nter insoluble in water, afforded by the ashes of plants. \nThe silica is known by not being dissolved by acids ; \nthe calcareous earth, unless the ashes have been very \nintensely ignited, dissolves with effervescence in muria- \ntic acid. Magnesia forms a soluble and crystallizable \nsalt, and lime, a difficultly soluble one with sulphuric \nacid. Alumina is distinguished from the other earths, \nby being acted upon very slowly by acids ; and in form- \ning salts very soluble in water, and difficult of crystalli- \nzation with them. \n\nThe earths appear to be compounds of the peculiar \nmetals mentioned page 40, and oxygene, one proportion \nof each. \n\nThe earths afforded by plants, are applied to no uses \nof common life ; and there are few cases in which the \nknowledge of their nature can be of importance, or af- \nford interest to the farmer. \n\nThe only metallic oxides found in plants are those of \niron and manganesum : they are detected in the ashes of \nplants ; but in very minute quantities only. AVhen the \nashes of plants are reddish brown, they abound in oxides \nof iron. When black or purple, in oxide of mangane- \nsum ; when these colours are^ mixed, they contain both \nsubstances. \n\nThe saline compounds contained in plants, or afford- \ned by their incineration, are very various. The sul- \nphuric acid combined with potassa, or sulphate of po- \ntassa, is one of the most usual. Common salt is like- \nwise very often found in the ashes of plants ; likewise \nphosphate of lime, which is insoluble in water, but solu- \nble in muriatic acid. Compounds of the nitric, muria- \ntic, sulphuric, and phosphoric acids, with alkalies and \n\nL \n\n\n\n82 \n\nearths, exist in the sap of many plants, or are afltbrded \nby their evaporation and incineration. The salts of po- \ntassa are distinguished from those of soda, by their pro- \nducing a precipitate in solutions of platina : those of \nlime are characterized by the cloudiness they occasion \nin solutions containing oxalic acid ; those of magnesia, \nby being rendered cloudy by solutions of ammonia. \nSulphuric acid is detected in salts by the dense white \nprecipitate it forms in solutions of baryta. Muriatic \nacid by the cloudiness it communicates to solution of \nnitrat of silver; and when salts contain nitric acid, \nthey produce scintillations by being thrown upon burn- \ning coals. \n\nAs no applications have been made of any of the \nneutral salts, or analogous compounds found in plants, \nin a separate state, it will be useless to describe them \nindividually. The following tables are given from M. \nTh. de Saussure\'s Researches on vegetation, and contain \nresults obtained by that philosopher. They exhibit the \nquantities of soluble salts, metallic oxides, and earths \naffordetl by the ashes of different plants. \n\n\n\n83 \n\n\n\nr-\' \n\n\n\n1*AMES OF PLANTS. \n\n\n\nW OS, \n\nO ^ \n\n** c \n\n\n\nLeaves of oak {queruis \n\nrobur) May 10 - \n\nDitto. Sept. 27 \n\nVVood of a young oak, \n\nMay 10 \n\nBark of ditto ...---.- \nEntire wood of oak - - - - \nAlburnum of ditto - - - - \nBark of ditto ...\xe2\x80\xa2\xe2\x80\xa2\xe2\x80\xa2.. \nCortical layers of ditto - - \nExtract of wood of ditto - \nSoil from wood of ditto - \nExtract from ditto - - - . \nLeaves of the poplar {po- \npulus nigra) May 26 - \n\nDitto, Sept. 12 \n\nWood of ditto, Sept. 12 - \n\nBark of ditto \n\nLeaves of hazel (^coryhis \navelland) May 1 - - - \xe2\x80\xa2 \nDo. washed in cold water \nLeaves of ditto, J une 22 \n\nDitto, Sept. 20 \n\nWood of ditto. May 1 - - \n\nBark of ditto \n\nEntire wood of mulberry, \n[tnorus nigra) Novem. \nAlburnum of ditto - . \xe2\x80\xa2 \xe2\x80\xa2 \nBark of ditto -.-..... \nCortical layers of ditto - - \nEntire wood of hornbeam, \n{carpinus betulus,) Nov. \nAlburnum of ditto - - \xe2\x80\xa2 - \n\nBark of ditto \n\nWood of liorse chesnut, \n[itsculus hyppocastanum) \n\nMay 10 \n\nLeaves of ditto. May 10 - \nLeaves of ditto, July 23 \xe2\x80\xa2 \n\nDitto, Sept. 27 \n\nFlowers of ditto. May 10 \n\nFruit of ditto, Oct. 5 \n\nPlants of peas (^pisum sa- \ntivum,) in flower - - - . \nPlants of peas (^pisum sa- \ntivum,) in flower, ripe \nPlants of vetches, [vicia \nfaba,) before flowering, \n\nMay 23 \n\nDitto in flower, June 23 - \nDitto ripe, July 23 - - - - \nDitto, seeds separated - - \n\nSeeds of ditto \n\nI Ditto in flower, raised in \nI distilled water . \xe2\x80\xa2 - \xe2\x80\xa2 . \n\n\n\n31 \n\n\n\n53 \n55 \n\n4 \n\n60 \n2 \n\n60 \n-3 \n61 \n41 \n111 \n\n66 \n\n93 \n\n8 \n\n72 \n\n61 \n57 \n62 \n70 \n5 \n62 \n\n7 \n13 \n\n89 \n88 \n\n\n\n150 \n\n122 \n\n66 \n\n115 \n\n33 \n\n39| \n\n\n\n745 \n49 \n\n\n\no ^ \n\n\n\n652 \n\n565 \n\n26 \n\n\n\n655 \n557 \n\n\n\n340 \n390 \n346 \n\n\n\n782 \n652 \n630 \n873 \n647 \n\n\n\n895 \n876 \n\n\n\nConstituents of 100 Parts of \nthe Ashes. \n\n\n\n47 \n17 \n\n26 \n7 \n\n38,6 \n32 \n\n7 \n\n7 \n51 \n24 \n66 \n\n36 \n26 \n\n\n\n24 \n18,25 \n\n28,5 \n4,5 \n4,5 \n\n24 \n3 \n3,75 \n\n10,5 \n\n\n\n26 \n8,2 \n22,7 \n11 \n24,5 \n\n21 \n\n26 \n\n7 \n\n10 \n\n22 \n18 \n\n4,5 \n\n9,5 \n50 \n24 \n13,5 \n50 \n82 \n\n49,8 \n\n34,25 \n\n\n\n55,5 \n\n55,5 \n\n50 \n\n42 \n\n69,28 \n\n60,1 \n\n\n\n13 \n\n7 \n16,75 \n\n5,3 \n\n23,3 \n19,5 \n14 \n12 \n35 \n5,6 \n\n2,25 \n27,25 \n\n8,6 \n16,5 \n\n23 \n36 \n4,5 \n\n\n\n0,12 \n\n23 \n\n12,25 \n\n63,25 \n\n32 \n\n11 \n\n06 \n\n65 \n\n10 \n\n\n\n29 \n36 \n27 \n60 \n\n22 \n44,1 \n29 \n36 \n8 \n54 \n\n53 \n24 \n45 \n\n48 \n\n26 \n15 \n59 \n\n\n\n12 \n\n17.25 \n\n22 \n\n\n\n14,5 \n13,5 \n17,75 \n5,75 \n27,92 \n\n30 \n\n\n\n3 \n14,5 \n\n0,12 \n\n0,25 \n\n2 \n\n7,5 \n\n1,5 \n\n0,5 \n\n32 \n\n\n\n5 \n11,5 \n\n3,3 \n\n4 \n\n2,5 \n4 \n11,3 \n\n22 \n0,25 \n0,25 \n\n0,12 \n1 \n15,25 \n0,12 \n\n0,12 \n\n1 \n\n1,5 \n\n\n\n0,64 \n1,75 \n\n1 \n\n1,75 \n2,25 \n2 \n\n\n\n14 \n\n\n\n25,24 \n\n\n\n,58 \n22,75 \n2;),65 \n23,5 \n21,5 \n22,75 \n\n8,5 \n\n\n\n1,25 15,75 \n1,5 18 \n\n\n\n3,5 \n4,12 \n4 \n36 \n\n\n\n0,5 \n2,3 \n11 \n\n\n\n1,5 \n1,5 \n1,75 \n1,75 \n\n\n\n1,5 \n1,5 \n\n1,5 \n\n2 \n\n1,5 \n\no \n\n0,12 \n1,75 \n\n0,25 \n0,25 \n1,12 \n1 \n\n2,25 \n\n1 \n\n0,12 \n\n\n\n24,5 \n23,2 \n\n24,7 \n\n22,2 \n\n21,5 \n\n17 \n\n32,2 \n\n26 \n\n20,38 \n21,5 \n23,13 \n24,38 \n\n26,03 \n\n29 \n\n30,38 \n\n\n\n0,25 \n\nI \n\n2,5 \n\n\n\n0,5 \n0,5 \n0,5 \n1 \n\n0,5 \n\n0,5 \n\n\n\n5,25 \n24,65 \n17,25 \n\n\n\n24,50 \n24,38 \n2*5 \n12.9 \n2,3 \n\n9.4 \n\n\n\n84 \n\n\n\n68 \n\n\n\n69 \n\n\n\n7.5 \n\n\n\nNAMES OF PLANTS. \n\n\n\nSolvdago Tii/ifuviii, bttbn; \n\nili)\xc2\xabcriiip;, JVliiy 1 \n\nDitto, just it) llowtT, July \n\nIf. .\' \n\nDitto, seeds n|)c, Sept. 20 \n\nI\'hints of tunisol [lieliim- \n\nthus (11171 iivx,) !\xc2\xbb mouth \n\nhctbrc llowering, June \n\n\'2\'.i \n\nDitto ill flower, July 23 - \nDitto, boni\'iiig r\\\\n\\ seetls, \n\nSipt. \'*(! \n\nWheal {triticiim sativum) \n\nin flower --.-..--. \n\nDitto, seeds rijie --..-- \n\nDitto, ft mouth before \n\nflowering ---....-. \n\nDitto, in flower, June 14 - \nDitto, seeds ripe ----- \n\nStraw (if wheat ------ \n\nSeeds of ditto ------- \n\nUran \n\nPlants of maize (zen mays) \na month before flower- \ning, June 23 ------ - \n\nDitto, ill flower, July 23 - \nDitto, seeds ripe ------ \n\nStalks of ditto \n\nSpikes of ditto ------- \n\nSeeds of ditto - \n\nChatVof Ijarley [hordeum \n\nviilffiirc) -.----., \nSeeds of ditto ---.-. \n\nDitto \n\nOats , \n\nLeaves of r/tododendrov \nfcrnigincvin, raised on \nJura, a limestone muini \n\ntain, June 20 \n\nLeaves of rhododendroti \nformqinni})!, raised on \nHreven, a granitic nioun \ntain, June \'27 ------ - \n\nHranches of ditto, June \n\n20 \n\nSpikes of tlitto, June 27 \nLeaves of tir [pi/nis abirx) \nraised on Jura, June 20 \nDitto, r;used on Bixven, \nJune 27 -------- . \n\nBrnnclies of Jiine, June 20 \n\nW hoi\'t leherry ,(T(7ftv\'\xc2\xab;7/\xc2\xabi \n\nmyrti/liis,) raised on Jh \n\nra, Aug. 29 \n\nDitto, raised on Biv.ven - \n\n\n\n\n\n\nIG \n\n\n\n92 \n\n\n\n93 \n\n\n\n30 \n\n\n\nI- \n\nel \n\npp.* \n\n\n\n753 \n\n\n\nf.99 \n\n\n\nConstituents of 100 Paris of \nthe Ashes. ^ \n\n\n\nf)7,.\'; \n\n59 \n48 \n\n\n\nf)3 \n(31 \n\n5,15 \n\n43,\'25 \n11 \n\nGO \n41 \n10 \n22,5 \n47,10 \n4,1C \n\n\n\n69 \n69 \n\n2,45 \n\n02 \n\n20 \n29 \n\n\n\n28 \n\n.... \n\n22 5 \n24 \n\n16 \n\n15 \n\n15 \n\n\n\n10,75 \n\n59 \nIt \n\n\n\n67 \n6 \n\n22,5 \n\n12,75 \n15 \n\n11,5 \n\n10,75 \n11,75 \n0,2 \n44,5 \n40,5 \n\n\n\n5,75 \n\n\n5 \n\n;?6 \n\n7,7i \n32,5 \n22 \n24 \n\n\n\n14 \n\n\n\n16,75 \n\n10 \n11.5 \n\n12,27 \n\n12 \n\n\n\n1,5 \n\n1,5 \n\n17,25 \n\n\n\n11,.5G \n12,5 \n\n\n\n0,25 \n\n0,25 \n\n0,25 \n0,25 \n0.25 \n1 \n\n\n\n0,25 \n0,25 \n\n\n\n12,5 \n\n\n\n43,25 \n\n\n\n16,75 \n\n39 \n29 \n\n\'i;3,5 \n\n29 \n\n\n\n42 \n\n\n\n1,5 \n1,5 \n\n.3,75 \n\n32 \n54 \n\n12,5 \n\n26 \n\n.\xe2\x96\xa0il \n\n61,5 \n0,5 \n0,5 \n\n\n\n7,5 \n7,5 \n\n18 \n\n1 \n\n57 \n35,5 \n21 \n00 \n\n\n\n0,75 \n\n\n\n0,5 \n1 \n\n2,5 \n\n19 \n\n\n\n0,75 \n\n0,75 \n.1.5 \n\n\n\n0,12 \n0,12 \n\n0,5 \n\n0,5 \n1 \n\n0,25 \n\n0,5 \n\n0,75 \n\nI \n\n0,25 \n\n0,25 \n\n\n\n0,25 \n0,25 \n\n0,5 \n\n0,12 \n\nt),5 \n0.25 \n0,12 \n11,25 \n\n\n\n3,25 \n\n\n\n5,77 \n\n5,4 \n11 \n\n1,6 \n\n5,5 \n\n\n\n0,5 3,12 \n5 9,5 \n\n\n\n18,25 \n\n21 \n18,75 \n\n\n\n16,07 \n18,78 \n\n17,75 \n\n12,25 \n18,75 \n\n15,5 \n\n21,5 \n\n23 \n\n8 \n\n7,6 \n8,6 \n\n\n\n17,25 \n17 \n\n3,05 \n\n0,88 \n\n2,25 \n\n2,8 \n\n29,S8 \n\n14,75 \n\n\n\n15,63 \n\n\n\n31,52 \n\n22,48 \n2V,5 \n\n2-1,13 \n\n19,5 \n\n\n\n1 9,38 \n17,5 \n\n\n\n85 \n\nBesides the pnuciplcs, the nature of wliicli has been \njust discussed, others have been described by chemi sts \nas belonging to the vegetable kingdom : thus a substance, \nsomewhat analogous to the muscular iibre of animals, \nhas been detected by Vauqueliu iu the papavv ; and a \nmatter similar to animal gelatine by Braconnot in the \nmushroom ; but in this place it would be improper to \ndwell upon peculiarities ; ray object being to oiler such \ngeneral views of the constitution of vegetables as may \nbe of use to the agriculturist. Some distinctions have \nbeen adopted l)y systematical authors wiiich I have not \nentered into, because they do not appear to me essential \nto this inquiry. Dr. Thomson, in his elaborate and \nlearned system of chemistry, has described six vegeta- \nble sul)stances, which he calls mucus, jelly, sarcocol, \nasparagin, innlin, and ulmin. He states that mucus ex- \nists in its purest form in linseed ; but Vauquelin has \nlately shewn, that the mucilage of linseed is, in its es- \nsential characters, analogous to gum; but that it is com- \nbined with a substance similar to animal mucus : vege- \ntable jelly. Dr. Thomson himself considers as a modifi- \ncation of gum. It is probable, from the taste of sarco- \ncol, that it is gum combined with a little sugar. Inulin \nis so analogous to starch, that it is probably a variety of \nthat principle : ulmin has been lately shewn by Mr. \nSmithson to be a compound of a peculiar extractive mat- \nter and potasssa ; and as|)aragin is probably a similar \ncombination. If slight difterences in chemical and phy- \nsical properties be considered as sufficient to establish \na diflerence in the species of vegetable substances, the \ncatalogue of them might be enlarged to almost any ex- \ntent. No two compounds procured from dillerent vege- \ntables are precisely alike ; and there are even difl\'erences \nin the qualities of the same compound, according to the \ntime in which it has been collected, and the manner in \nwhich it has been prepared : the great use of classifica- \ntion in science is to assist the memory ; and it ought to \nbe founded upon the similarity of properties which are \ndistinct, characteristic and invariable. \n\nThe analysis of any substance containing mixtures of \nthe diilerent vegetable principles, may be made in such \na manner as is necessary for the views of the agricultu- \n\n\n\nlist with facility. A given quantity, say 200 grains, of \nthe substance should be powdered, made into a paste or \nmass, with a small quantity of water, and kneaded in \nthe hands, or rubbed in a mortar for some time under \ncold water ; if it contain much gluten, that principle will \nseparate in a coherent mass. After this process, whe- \nther it has afforded gluten or not, it should be kept in \ncontact with half a pint of cold water for three or four \nhours, being occasionally rubbed or agitated : the solid \nmatter should be separated from the fluid by means of \nblotting paper : the fluid should be gradually heated ; if \nany flakes appear, they are to be separated by the same \nmeans as the solid matter in the last process, i. e. by \nfiltration. Tlie fluid is then to be evaporated to dry- \nness. The matter obtained is to be examined by ap- \nplying moist paper, tinged with red cabLage juice, or \nviolet juice to it ; if the paper become red, it contains \nacid matter; if it become green, alkaline matter; and the \nnature of the acid or alkaline matter may be known by \napplying the tests described page 77, 78, 79. If the \nsolid matter be sweet to the taste, it must be supposed \nto contain sugar; if bitterish, bitter principle, or extract; \nif astringent, tannin : and if it be nearly insipid, it must \nbe principally gum or mucilage. To separate gum or \nmucilage from the other principles, alcohol must be boil- \ned upon the solid matter, which will dissolve the sugar \nand the extract, and leave the mucilage ; the weight of \nwhich may be ascertained. \n\nTo separate sugar and extract, the alcohol must be \nevaporated till crystals begin to fall down, which are su- \ngar ; but they will generally be coloured by some ex- \ntract, and can only be purified by repeated solutions in \nalcohol. Extract may be separated from sugar by dis- \nsolving the solid, obtained by evaporation from alcohol, \nin a small quantity of water, and boiling it for a long \nwhile in contact with the air. The extract will gradu- \nally ftiU down in the form of an insoluble powder, and \nthe sugar will remain in solution. \n\nIf tannin exist in the first solution made by cold wa- \nter, its separation is easily effected by the process de- \nscribed page 66. The solution of isinglass must be \ngradually added, to prevent the existence of an excess \n\n\n\n87 \n\nof animal jelly in the solution, which might he mistaken \nfor mucilage. \n\nWhen the vegetahle substance, the subject of experi- \nment, will afford no more principles to cold water, it \nmust be exposed to boiling water. This will unite to \nstarch if there be any, and may likewise take up more \nsugar, extract, and tannin, provided they be intimately \ncombined with the other principles of the compound. \n\nThe mode of separating starch is similar to that of se- \nparating mucilage. \n\nIf after the action of hot water any thing remain, the \naction of boiling alcohol is then to be tried. This will \ndissolve resinous matter ; the quantity of which may be \nknown by evaporating the alcohoL \n\nThe last agent that may be applied is ether, which \ndissolves elastic gum, though the application is scarce- \nly ever necessary ; for if this principle be present, it \nmay be easily detected by its peculiar qualities. \n\nIf any fixed oil or wax exist in the vegetable substance, \nit will separate during the process of boiling in water, \nand may be collected. Any substance not acted upon \nby water, alcohol, or ether, must be regarded as woody \nfibre. \n\nIf volatile oils exist in any vegetable substances, it is \nevident they may be procured, and their quantity ascer- \ntained, by distillation. \n\nWhen the quantity of fixed saline, alkaline, metallic, \nor earthy matter in any vegetable compound is to be as- \ncertained, the compound must be decomposed by heat, \nby exposing it, if a fixed substance, in a crucible, to a \nlong continued red heat ; and if a volatile substance, by \npassing it through an ignited porcelain tube. The na- \nture of the matter so produced, may be learnt by apply- \ning the tests mentioned in page 81. \n\nThe only analyses in which the agricultural chemist \ncan often wish to occupy himself, are those of substan- \nces containing principally starch, sugar, gluten, oils, mu- \ncilage, albumen, and tannin. \n\nThe two following statements will afford an idea of \nthe manner in which the results of experiments may be \narranged. \n\nThe first is a statement of the composition of ripe peas. \n\n\n\n88 \n\ndeduced from experiments made by Einliof ; the second \nare of the products afforded by oak bark, deduced from \nexperiments conducted by myself. \n\nParts. \n\n3840 parts of ripe peas afford, of starch , 1265 \nFibrous matter analogous to ^ \nstarch, with the coats ofC 840 \nthe peas " " 3 \n\n3840 parts of a substance analogous to gluten 550 \n\nMucilage . . - - 249 \nSaccharine matter - - 81 \n\nAlbumen . . - . 66 \n\nVolatile matter - - - 640 \nEarthy phosphates - - 11 \n\nLoss 229 \n\n1000 parts of dry oak bark, from a small tree depri- \nved of epidermis, contain, \n\nOf woody fibre - - - - 876 \n\n\xe2\x80\x94 tannin ----- 57 \n\n\xe2\x80\x94 extract - - - - - 31 \n\n\xe2\x80\x94 mucilage . - - - 18 \n-\xe2\x80\x94 matter rendered insoluble during 1 \n\nevaporation, probably a mixture > 9 \nof albumen and extract t ) \n\n\xe2\x80\x94 loss, partly saline matter - - 30 \n\nTo ascertain the primary elements of the different ve- \ngetable principles, and the proportions in which they \nare combined, different methods of analysis have been \nadopted. The most simple are their decomposition by \nheat, or their formation into new products by combus- \ntion. \n\nWhen any vegetable principle is acted on by a strong \nred heat, its elements become newly arranged. Such \nof them as are volatile are expelled in the gaseous form ; \nand are either condensed as fluids, or remain permanent- \nly elastic. The fixed remainder is either carbonaceous, \nearthy, saline, alkaline, or metallic matter. \n\nTo make correct experiments on the decomposition of \nvegetable substances by heat, requires a complicated ap- \n\n\n\n89 \n\nparatus, much time and labour, and all the resources \nof the philosophical chemist : but such results as are \nuseful to the agriculturist may be easily obtained. The \napparatus necessary is a green glass retort, attached by \ncement to a receiver, connected with a tube passing un- \nder an inverted jar of known capacity, filled with wa- \nter.* A given weight of the substauce is to be heated \nto redness in the retort over a charcoal fire ; the receiver \nis to be kept cool, and the process continued as loug as \nany elastic matter is generated. The condensible fluids \nwill collect in the receiver, and the fixed residuum will \nbe found in the retort. The fluid products of the dis- \ntillation of vegetable substances are principally water, \nwith some acetous and mucous acids, and empyreumatic \noil, or tar, and in some cases ammonia. The gases are \ncarbonic acid gas, carbonic oxide, and carburetted hy- \ndrogene ; sometimes with olefiant gas, and hydrogene ; \nand sometimes, but more rarely, with azote. Carbonic \nacid is the only one of those gases rapidly absorbed by \nwater ; the rest are inflammable ; olefiant gas burns witli \na bright white light ; carburetted hydrogene with a light \nlike wax ; carbonic oxide Avith a feeble, blue flame. \nThe properties of hydrogene and azote liave been de- \nscribed in the last lecture. The specific gravity of \ncarbonic acid gas, is to that of air as 20.7 to 13.7, and \nit consists of one proportion of carbon 11.4, and two \nof oxygene 30. \xe2\x80\xa2 The specific gravity of gaseous oxide \nof carbon, is taking the same standard 13.2, and it con- \nsists of one proportion of carbon, and one of oxygene. \n\nThe specific gravities of carburetted liydrogene and \nolefiant gas are respectively eight and thirteen ; both \ncontain four proportions of hydrogene ; the first contains \none proportion, the second two proportions of carbon. \n\nIf the weight of the carbonaceous residuum be added \nto the weight of the fluids condensed in the receiver, \nand they be subtracted from the whole weight of the \nsubstance, the remainder will be the weight of the gas- \neous matter. \n\nThe aceous and mucous acids, and the ammonia form- \ned are usually in very small quantities ; and by com- \n\n* See Fig. 1 4. \nM \n\n\n\n90 \n\njiariiii; the proportions^ of water and charcoal with the \nquantity of the i:;as!ies, takini; into account their qualities, . \na a;eneral idea may be formed of the^ composition of the \nsubstance. The [iroportions of tlie elements in the \ne;rcater number of tlie vegetable substances which can \nbe used as food, have been already ascertained by phi- \nlosophical chemists, and have been stated in the preced- \ning pjiges ; the analysis by distillation may, however, \niu some cases, be useful in estinuiting the pow ers of ma- \nnures, in a manner that will be explained in a future \nlecture. \n\nThe statements of the composition of vegetable sub- \nstances, quoted from M. M. Gay Lussac and Thenard, \nwere obtained by these philosophers by exposing the \nsul)stances to the action of heated hyper-oxymuriate of \npotassa; a body that consists of potassium, chlorine,\' \nand oxygene; and which aflbrded oxygene to the carbon \nand the hydrogene. Their experiments were made in \na peculiar apparatus, and required great caution, and \nwere of a a ery delicate nature. It will not therefore \nbe necessary to enter upon any details of them. \n\nIt is evident from the whole tenor of the statements \nwhich have been made, and the most essential vegeta- \nble substances consist of hydrogene, carbon, and oxy- \ngene in difterent proportions, generally alone, but in \nsome few^ cases combined with azote. The acids, al- \nkalies, earths, metallic oxides, and saline compounds, \nthough necessary in the vegetable cecouomy, must be \nconsidered as of less importance, particularly in their \nrelation to agriculture, tlian the other principles : and as \nit appears from M. de Saussure\'s table, and from other \nexperiments, they differ in the same species of vegeta- \nble when it is raised on different soils. \n\nM. M. Gay Lussac and Thenard have deduced three \npropositions, which they have called lairs from their ex- \nperiments on vegetable substances. The Jirst is, ^\'that \na vegetable substance is always acid w henever the oxy- \ngene it contains is to the hydrogene in a greater pro- \nportion than in w ater.\'" \n\nThe second. \xe2\x80\xa2\xe2\x80\xa2 that a vegetable substance is always \nresinous or oily or spiritous whenever it contains oxy- \ngene in a smaller proportion to the hydrogene than exists \niu ^va(cr.*^ \n\n\n\n91 \n\nThe third, " that a ve2;etable substance is neitlier acid \nnor resinous ; but is either saccharine or mucilaginous, \nor analogous to woocly fibre or starcli, whenever the \noxygene and hydrogene in it are in the same proportions \nas in water. \n\nNew experiments upon other vegetable substances, \nbesides those examined by M. M. Gay Lussac and \nThenard, are required before these interesting conclu- \nsions can be fully admitted. Their researches establish, \nhowever, the. close analogy between several vegetable \ncompounds differing in their sensible qualities, and com- \nbined with those of other chemists, offer simple expla- \nnations of several processes in nature and art, by which \ndifferent vegetable substances are converted into each \nother, or changed into new compounds. \n\nGum and sugar afford nearly the same elements by \nanalysis ; and starch differs from them only in contain- \ning a little more carbon. The peculiar properties of \ngum and sugar must depend chiefly upon the different ar- \nrangement, or degree of condensation of their elements ; \nand it would be natural to conceive from the composi- \ntion of these bodies, as well as that of starch, that all \nthree would be easily convertible one into the other ; \nwhich is actually the case. \n\nAt the time of the ripening of corn, the saccharine \nmatter in the grain, and that carried from the sap ves- \nsels into the grain, becomes coagulated, and forms starch. \nAnd in the process of malting, the converse change oc- \ncurs. The starch of grain is converted into sugar. As \nthere is a little absorption of oxygene, and a formation \nof carbonic acid in this case, it is probal)le that the \nstarch loses a little carbon, which combines with the \noxygene to form carbonic acid ; and probably the oxy- \ngene tends to acidify the gluten of the grain, and thus \nbreaks down the texture of the starch ; gives a new ar- \nrangement to its elements, and renders it soluble in wa- \nter. \n\nMr. Cruikshank, by exposing syrup to a substance \nnamed phosphuret of lime, which has a great tendency \nto decompose water, converted a part of the sugar into \na matter analogous to mucilage. And M. Kirchoff, re- \ncently, has converted starch into sugar by a very sim- \n\n\n\n92 \n\n|>le pi\'(Ke;?s, iliat of boiling in very diluted suipliiu\'i( \nacid. The proportions are 100 parts of starclj, 400 \nparts of water, and 1 part of sulphuric acid by weiglrt. \nThis mixture is to be kept boiling for 40 hours ; the loss \nof water by evaporation being supplied by new cpianti- \nties. The acid is to be neutrallized by lime ; and the \nsugar crystallized by cooling. This experiment has \nbeen tried with success by many persons. Dr. Tuthili, \nfrom a pound and a half of potato starch, procured a \npound and a quarter of crystalline, brown^sugar ; which \nhe conceives possesses properties intermediate between \ncane sugar and grape sugar. \n\nIt is probable that the conversion of starch into sugar \nis effected merely by the attraction of the acid for the \nelements of sugar ; for various experiments have been \nmade, which prove that the acid is not decomposed, and \nthat no elastic matter is set free : probably the colour of \nthe sugar is owing to the disengagement, or new combi- \nnation of a little carbon, the slight excess of which, as \nhas been just stated, constitutes the only difference per- \nceptible by analysis between sugar and starch. \n\nM. Bouillon la Grange, by slightly roasting starch, \nhas rendered it soluble in cold water ; and the solution \nevaporated afforded a substance, having the characters \nof mucilage. \n\nGluten and albumen differ from the other vegetable \nproducts, principally by containing azote. When glu- \nten is kept long in water it undergoes fermentation; am- \nmonia, (which contains its azote) is given off with ace- \ntic acid : and a fatty matter and a substance analogous \nto woody fibre remain. \n\nExtract, tannin, and gallic acid, when their solutions \nare long exposed to air, deposit a matter similar to woody \nfibre ; and the solid substances are rendered analogous \nto woody fibre by slight roasting ; and in tliese cases it \nis probable that part of their oxygene and hydrogene is \nseparated as water. \n\nAll the other vegetable principles differ from the ve- \ngetable acids in containing more hydrogene and carbon, \nor less oxygene ; many of them therefore are easily con- \nverted into vegetable acids by a mere subtraction of some \nproportions of hydrogene. The vegetable acids, for the \n\n\n\n9a \n\nmost part, are convertible into each otlier by easy pro- \ncesses. The oxalic contains most oxygene ; the acetic \nthe least: and this last substance is easily formed by the \ndistillation of other vegetable substances, or by the ac- \ntion of the atmosphere on such of them as are soluble in \nwater ; probably by the mere combination of oxygene \nwith hydrogene and carbon, or in some cases by the sub- \ntraction of a portion of hydrogene. \n\nAlcohol, or spirits of uine, has been often mentioned \nin the course of these Lectures. This substance was \nnot describe\'d amongst the vegetable principles, because \nit has never been found ready formed in the organs of \nplants. It is procured by a change in the principles of \nsaccharine matter, in a process called vinous fermenta- \ntion. \n\nThe expressed juice of the grape contains sugar mu- \ncilage, gluten, and some saline matter, principally com- \nposed of tartaric acid: when this juice, or must, as it is \ncommonly called, is exposed to the temperature of about \n70\xc2\xae, the fermentation begins : it becomes thick and tur- \nbid ; its temperature increases, and carbonic acid gas is \ndisengaged iii abundance. In a few days the fermenta- \ntion ceases ; the solid matter that rendered the juice tur- \nbid falls to the bottom, and it clears ; the sweet taste of \nthe fluid is in great measure destroyed, and it is become \nspirituous. \n\nFabroui has shewn that the gluten in must is essen- \ntial to fermentation ; and that chemist has made saccha- \nrine matter ferment, by a<lding to its solution in water, \ncommon vegetable gluten and tartaric acid. Gay Lus- \nsac has demonstrated that must will not ferment when \nfreed from air by boiling, and placed out of tiie contact \nof oxygene ; but that fermentation begins as soon as it \nis exposed to the oxygene of air, a litth^ of that princi- \nple being absorbed; and ihat it then continues indepen- \ndent of the presence of the atmosphere. \n\nIn the manufacture of ale and porter, the sugar form- \ned during the germination of barley is made to ferment \nby dissolviug it in water with a little yeast, which con- \ntains gluten in the state proper for producing fermenta- \ntion, and exposing it to the requisite temperature ; car- \nbonic acid ;;as is given off as in the fermentation of must, \nand the liquor gradually becomes spirituous. \n\n\n\n94 \n\nSimilar plisenomena occur in the fermentation of the \nsugar in the juice of apples and other ripe fruits. It* \nappears that fermentation depends entirely upon a new \narrangement of the elements of sugar ; part of the car- \nbon uniting to oxygene to form a carbonic acid, and the \nremaining carbon, hydrogene, and oxygene combining \nas alcohol ; and the use of the gluten or yeast, and the \nprimary exposure to air seems to be to occasion the for- \nmation of a certain quantity of carbonic acid ; and this \nchange being once produced is continued ; its agency \nmay be compared to t)iat of a spark in producing the in- \nflammation of gunpowder ; the increase of temperature \noccasioned by tlie formation of one quantity of carbonic \nacid occasions tlie combination of the elements of another \nquantity. \n\nThe results obtained by different chemists in experi- \nments on the analysis of alcohol differ so much, that no \ngeneral conclusions can be drawn from them. If it be \nsupposed that one proportion of carbonic acid is form- \ned in the fermentation of sugar, then, according to Dr. \nThomson\'s analysis of sugar, which gives its composi- \ntion as 3 proportions of carbon, 4 of oxygene, and 8 of \nliydrogene, alcohol would consist of 2 proportions of \ncarbon, 2 of oxygene, and 8 of hydrogene ; and it might \nbe considered as containing the same elements as two \nproportions of olefiant gas, with tw o proportions of oxy- \ngene. \n\nAlcohol in its purest known form, is a highly inflam- \nmable liquid, of specific gravity 796, at the temperature \nof 60\xc2\xab ; it boils at about 170^ Fahrenheit. This alco- \nhol is obtained by repeated distillation of the strongest \ncommon spirit from the salt called by chemists muriate \nof lime, it having been previously heated red hot. \n\nThe strongest alcohol obtained by the distillation of \nspirits without salts, has seldom a less specific gravity \nthan 825 at 60\xc2\xb0 ; and it contains, according to Lowitz\'s \nexperiments, 89 parts of the alcohol of 796, and 11 parts \nof water. The spirit established as \'proof spirit by act \nof parliament passed in 1762, ought to have the specific \ngravity of 916 ; and this contains nearly equal weights \nof pure alcohol and water. \n\nThe alcohol in fermented liquors is in combination \n\n\n\n95 \n\nwith M\'aier, colouring matter, sugar, mucilage, and the \nvegetable acids. It has been often doubted whether it \ncan be procured by any other process than distillation ; \nand some persons have even supposed that it is formed \nby distillation. The recent experiments of Mr. Brande \nare conclusive against both these opinions. That gentle- \nman has shewn that the colouring and acid matter in \nwines may be, for the most part, separated in a solid \nform by the action of a solution of sugar of lead (ace- \ntate of lead,) and that the alcohol may be then obtained \nby abstracting the water by means of hydrate of potas- \nsa or muriate of lime, without artiiicial heat. \n\nThe intoxicating powers of fermented liquors depend \non the alcohol that they contain ; but their action on the \nstomach is modified by the acid, saccharine, or mucila- \nginous substances they hold in solution. Alcohol pro- \nbably acts with most eificacy when it is most loosely \ncombined ; and its energy seems to be impaired by union \nwith large quantities of water, or with sugar or acid, or \nextractive matter. \n\nThe following table contains the results of Mr. \nBrande\'s experiments on the quantity of alcohol of 825 \nat 60\xc2\xb0, in different fermented liquors. \n\n\n\n96 \n\n\n\nWINJE. \n\n\n\nPort - - - - \n\n\n21,40 \n\n\nDitto - - . \n\n\n22,30 \n\n\nDitto - . - - \n\n\n23,39 \n\n\nDitto - - - \n\n\n23,71 \n\n\nDitto - . . - \n\n\n24,29 \n\n\nDitto - > - \n\n\n35,83 \n\n\nMadeira - - - \n\n\n19,34 \n\n\nDitto - - - \n\n\n21,40 \n\n\nDitto . - - . \n\n\n23,93 \n\n\nDitto - - - \n\n\n24,42 \n\n\nSherry - - . \n\n\n18,25- \n\n\nDitto - - - \n\n\n18,79 \n\n\nDitto - - . - \n\n\n19,81 \n\n\nDitto - - - \n\n\n19,83 \n\n\nClaret - . - - \n\n\n12,91 \n\n\nDitto - - - \n\n\n14,03 \n\n\nDitto - - - - \n\n\n16,32 \n\n\nCalcavella - - \n\n\n18,10 \n\n\nLisbon - - - \n\n\n18,94 \n\n\nMala.^a - - - \n\n\n17,2G \n\n\nBucellas - - - \n\n\n18.49 \n\n\nRed Madeira - \n\n\n18,40 \n\n\nMalmsey Madeira \n\n\n1G,40 \n\n\nMarsala - - - \n\n\n25,87 \n\n\nDitto - - - \n\n\n17,26 \n\n\nRed Champas^nc \n\n\n11,30 \n\n\nWhite Champagne \n\n\n12,80 \n\n\nBnrginidy - - \n\n\n14,53 \n\n\nDitto - - - \n\n\n11,95 \n\n\n\nWINE. \n\n\n\nWhite Hermitage \nRed Hermitage \nHock - - - - \nDitto - - - \nVin de Grave \nFrontignac - - \nCoti Roti - - - \nRousillon - - \nCape Madeira - \nCape Miischat - \nConstantia - - \nTent - - . - \nSheraaz - - - \nSyracuse - - \n>Jice - . - - \nTokay - - - \nRaisin Wine - - \ndrape Wine \nCurrant Wine - \nGooseberry Wine \nElder Wine \nCider - - - - \nPerry _ - - \nBro\\A\'n Stout - - \nAle .... \nBi\'andy - - - \nRum . . - - \nHollands - - . \n\n\n\n1 \n\n\n\n\n\n\n17,43 \n\n12,32 \n\n14,37 \n\n8,88 \n\n12,80 \n\n12,79 \n\n12,32 \n\n17,26 \n\nIS, 11 \n\n18,25 \n\n19,75 \n\n13,30 \n\n15,52 \n\n15,28 \n\n14,63 \n\n9,88 \n\n25,77 \n\n18,11 \n\n20,55 \n\n11,84 \n\n9,87 \n\n9,87 \n\n9,87 \n\n6,80 \n\n8,88 \n\n53,39 \n\n53,68 \n\n51,60 \n\n\n\nwmmmMmmiBm \n\n\n\n97 \n\nThe spirits distilled from diflfereiit fermented liquors \ndiffer in their flavour : for peculiar odorous matter, or \nvolatile oils, rise in most cases with the alcohol. The \nspirit from malt usually has an cmpyreumatic taste like \nthat of oil, formed by the distillation of vegetable sub- \nstances. The best brandies seem to owe their flavour \nto a peculiar oily matter, formed probably by the action \nof the tartaric acid on alcohol; and rum derives its char- \nacteristic taste from a principle in the sugar cane. All \nthe common spirits may, I find, be deprived of their pe- \nculiar flavour by repeatedly digesting them with a mix- \nture of well burnt charcoal and quicklime ; they then af- \nford pure alcohol by distillation. The cogniac brandies, \nI find, contain vegetable prussic acid, and their flavour \nmay be imitated by adding to a solution of alcohol in \nwater of the same strength, a few drops of the ethereal \noil of wine produced during the formation of ether,* and \na similar quantity of vegetable prussic acid procured \nfrom laurel leaves or any bitter kernels. \n\nI have mentioned ether in the course of this Lecture ; \nthis substance is procured from alcohol by distilling a \nmixture of equal parts of alcohol and sulphuric acid. It \nis the lightest known liquid substance, being of a spe- \ncific gravity 632 at 60^. It is very volatile, and rises \nin vapour even by the heat of the body. It is highly in- \nflammable. In the formation of ether it is most proba- \nble that carbon and the elements of water are separated \nfrom the alcohol, and that ether differs from alcohol in \ncontaining less oxygene and carbon ; but its composi- \ntion has not yet been accurately ascertained. Like al- \ncohol it possesses intoxicating powers. \n\nA number of the changes taking place in the vegeta- \nble principles depend upon the separation of oxygene \nand hydrogene as Avater from the compound ; but there \nis one of very great importance, in wliich a new combi- \nnation of the elements of water is the principal opera- \ntion. This is in the manufacture of bread. When any \nkind of flour, which consists principally of starch, is \n\n* In the process of tlie distillation of ulcoliol and sulphuric acid af- \nter tlie ether is procured ; by a higher degree of heat, a yellow fluid \nis produced, whicli is the substance in question. It has a f, agrant \nsmell and an agreeable ta-ite, / \n\nN I \n\n\n\nmade into a paste with water, and immediately and gra- \ndually Iieated to about 440\xc2\xb0, it increases in weight, and \nis found entirely altered in its properties ; it has lost its \nsolubility in water, and its power of being converted \ninto sugar. In ibis state it is unleavened bread. \n\nA\\ hen the Hour of corn or the starch of potatoes, mix- \ned with boiled })otaioes, is made into a paste with water, \nkept warm, aiul suU\'ered to remain 30 or 40 hours, it \nferments, carbonic acid gas is .disengaged from it, and \nit becomes filled with globules of elastic iluid. In this \nstate it is raised dough, and aflbrds by baking, leavened \nbread ; but this bread is sour and disagreeable to the \ntaste ; and leavened bread for use is made by mixing a \nlittle dough, that lias fermented, Avith new dougli, and \nkneading them together, or by kneading the bread with \na small quantity of yeast. \n\nIn the formation of wheaten bread more than^. of the \nelements of water combine with the flour ; more water is \nconsolidated in the formation of bread from barley, and \nstill more in that from oats; but the gluten in wheat, be- \ning in much larger quantity than in otlier grain, seems \nto form a combination with the starch and water, which \nrenders wheaten bread more digestible than the other \nspecies of bread. \n\nThe arrangement of many of the vegetable principles \nin the diil\'erent parts of plants has been incidentally \nmentioned in this Lecture ; but a more particular state- \nment is required to allbrd just views of the relation be- \ntween their organization and chemical consritution, which \nis an o])ject of great importance. The tubes and hex- \nagonal cells in the vascular system of plants are compo- \nsed of woody fibre ; and when they are not filled with \nfluid matter they contain some of the solid materials \nwhi( h formed a constituent part of the fluids belonging \nto them. \n\nIn the roots, trunk, and branches, the bark, albur- \nnum, and heartwood, the leaves and flowers ; the great \nbasis of the solid parts is woody fibre. It forms by far \nthe greatest part of the heartwood and bark ; there is \nless in the alburnum, and still less in the leaves and \nflowers. The alburnum of the birch contains so much \nsui;ar and mucilage, that it is sometimes used in the \n\n\n\ny9 \n\nNorth of Europe as a substitute lor bread. The leaves \nof the cabbage, broccoli, and seacale, contain much mu- \ncilage, a little saccharine matter, and a little albumen. \n\nFrom 1000 parts of the leaves of common cabbage I \nobtained 41 parts of mucilage, 24 of sugar, and 8 of al- \nbuminous matter. \n\nIn bulbous roots, and sometimes in common roots, a \nlarge quantity of starch, albumen, and mucilage, are \noften found deposited in the vessels ; and they are most \nabundant after the sap has ceased to flow ; and aftbrd a \nnourishment for the early shoots made in spring. The \npotato is the bulb that contains the largest quantity of \nsoluble matter in its cells and vessels ; and it is of most \nimportance in its application as food. Potatoes in ge- \nneral afford from one-fifth to one-seventh their weight \nof dry starch. From 100 parts of the common Kidneij \npotato, Dr. Pearson obtained from 32 to 28 parts of meal, \nwhich contained from 23 to 20 of starch and mucilage : \nand 100 parts of the Apple potato in various experiments, \nafford me from 18 to 20 parts of pure starch. From five \npounds of the variety of the potato called Captain hart, \nMr. Skrimshire, jun. obtained 12 oz. of starch, from the \nsame quantity of the Hough red potato 10| oz., from the \nMoulton white 111, from the Yorkshire kidney 10| oz. \nfrom Hundred eyes 9 oz., from Purple red 8j, from Ox \nnolle 8j.. The other soluble substances in the potato \nare albumen and mucilage. \n\nFrom the analysis of Einhoff it appears that 7680 \nparts of potatoes afford \n\nOf Starch 1153 \n\n\xe2\x80\x94 Fibrous matter analogous to starch 640 \n\n\xe2\x80\x94 Albumen - - - - 107 \n\n\xe2\x80\x94 Mucilage in the state of a satura- , ^.^ \nted solution ... \n\n\n\n2112 \n\n\n\nSo that a fourth part of the weight of the potato at least \nmay be considered as nutritive matter. \n\nThe turnip, carrot, and parsnip, afford principally \nsaccharine, mucilaginous, and extractive matter. I ob- \ntained from 1000 parts of common turnips seven parts \n\n\n\nlOU \n\nof rtiucilai^c, 34 of saccharine mattev, and nearly one \npart of albumen. 1000 parts of carrots furnished 95 \nparts of sugar, three parts of nnicilage, and one-half of \nextract; 1000 parts of parsnip aiforded 90 parts of sac- \ncharine matter, and nine parts of mucilage. The Wal- \ncheran or ichite carrot, gave in 1000 parts, 98 parts of \nsugar, two parts of mncilage, and one of extract. \n\nFruits, in the organization of their soft parts, approach \nto the nature of bulbs. They contain a certain quanti- \nty of nourishment laid up in their cells for the use of \nthe embryon plant ; mncilage, sugar, starch, are found \nin many of them often combined with vegetable acids. \nMost of the fruit trees common in Britain have been na- \nturalized on account of the saccharine matter they con- \ntain, which, united to the vegetable acids and mucilage, \nrenders tliem at once agreeable to the taste and nutri- \ntive. \n\nThe value of fruits for the manufacture of fermented \nliquors may be judged of from the specific gravity of their \nexpressed juices. The best cider and perry are made \nfrom those apples and pears that afford the densest juices; \nand a comparison between different fruits may be made \nAvith tolerable accuracy by plunging them together into \na saturated solution of salt, or a strong solution of sugar : \nthose that sink deepest will afford the richest juice. \n\nStarch or coagulated mucilage forms the greatest part \nof the seeds and grains used for food ; and they are ge- \nnerally combined with gluten, oil, or albuminous mat- \nter. In corn, with gluten, in peas and beans, with al- \nbuminous matter; and in rape-seed, hemp-seed, linseed, \nand the kernels of most nuts with oils. \n\nI found 100 parts of good full grained wheat sown in \nautumn to afford \n\nOf starch - - 77 \n\n\xe2\x80\x94 Gluten - - 19 \n100 parts of wheat sown in spring, \n\nOf starch - - 70 \n\n\xe2\x80\x94 Gluten - - 24 \n100 parts of Barbary wheat. \n\nOf starch - - 74 \n\n\xe2\x80\x94 Gluten - - 23 \n100 parts of Sicilian wheat, \n\n\n\n101 \n\nOf starch - - 75 \n\xe2\x80\x94 Gluten - - 21 \n\n1 have examined dijQTerent specimens of North Ameri- \ncan wheat, all of them have contained rather more glu- \nten than the British. In general the wheat of warm cli- \nmates abounds more in gluten, and in insoluble parts ; \nand it is of greater specific gravity, harder, and more \ndifficult to grind. \n\nThe wheat of the south of Europe, in consequence of \nthe larger quantity of gluten it contains, is peculiarly fit- \nted for making macaroni, and other preparations of flow- \ner in which a glutinous quality is considered as an ex- \ncellence. \n\nIn some experiments made on barley, I obtained from \n100 parts of full and fair Norfolk barley, \n\nOf Starch - - - 79 \n\n\xe2\x80\x94 Gluten - - - 6 \n-\xe2\x80\x94Husk , - . 8 \n\nThe remaining seven parts saccharine matter. The su- \ngar in barley is probably the chief cause why it is more \nproper for malting than any other species of grain. \n\nEinhoff has published a minute analysis of barley \nmeal. He found in 3840 parts, \n\nOf volatile matter - - 360 \n\n\xe2\x80\x94 Albumen - - . 44 \n\n\xe2\x80\x94 Saccharine matter - 200 \n\n\xe2\x80\x94 Mucilage - - - 176 \n\n\xe2\x80\x94 Phosphate of lime, with some \n\nalbumen - - . 9 \n\n\xe2\x80\x94 Gluten - - - 135 \n\n\xe2\x80\x94 Husk, with some gluten and \n\nstarch - - - 260 \n\n\xe2\x80\x94 Starch not quite free from \n\ngluten - - - 2580 \n\n\xe2\x80\x94 Loss - - - - 78 \n\nllye afforded to Einhoff, in 3840 parts ; 2520 meal, \n930 husk, and 390 moisture ; and the same quantity of \nmeal analyzed gave, \n\n\n\n102 \n\n\n\nOf starch \n\n\n- 2345 \n\n\n\xe2\x80\x94 Albumen \n\n\n126 \n\n\n\xe2\x80\x94 Mucilage \n\n\n436 \n\n\n\xe2\x80\x94 Saccharine matter \n\n\n126 \n\n\n\xe2\x80\x94 Gluten not dried \n\n\n364 \n\n\nRemainder husk and loss. \n\n\n\n\n\nI obtained from 1000 parts of rye, grown in Suifolk^ \n61 parts of starch, and five parts of gluten, \n\n100 parts of oats, from Sussex, afibrded me 59 parts \nof starch, six of gluten and two of saccharine matter. \n\n1000 parts of peas, grown in Norfolk, afforded me \n501 parts of starch, 22 parts of saccharine matter, 35 \nparts of albuminous matter, and 16 parts of extract, \nwhich become insoluble during evaporation of the sac- \ncharine fluid. \n\nFrom 3840 parts of marsh beans (Vicia faba,) Ein- \nhoff obtained, \n\nOf Starch ... - 1312 \n\n\xe2\x80\x94 Albumen - - - - 31 \n\n\xe2\x80\x94 Other matters which may be"] \nconceived nutritive; such as ! 49^4 \ngummy, starchy, fibrous mat- j \n\nter analogous to animal matter J \n\nThe same quantity of kidney beans (Phaseolus vul- \ngaris y) afforded, \n\nOf matter analagous to starch - 1805 . \n\n\xe2\x80\x94 Albumen and matter ap- \') \n\nproaching to animal mat- V 851 \n\nter in its nature - ) \n\n\xe2\x80\x94 Mucilage - - - 799 \n\nFrom 3840 parts of lentiles he obtained 1260 parts \nof starcli, and 1433 of a matter analogous to animal mat- \nter. \n\nThe matter analogous to animal matter is described \nby Einhoff ; as a glutinous substance insoluble in wa- \nter ; soluble in alcohol when dry, having the appearance \nof glue ; probably a peculiar modification of gluten. \n\n\n\n103 \n\nFrom 16 parts of hemp-seeds Biicholz obtained three \nparts of oil, three and a half parts of albumen, about \none and three quarters of saccharine and gummy matter. \nThe insoluble husks and coats of the seeds weighed six \nand one-eighth parts. \n\nThe different parts of flowers contain different sub- \nstances : the pollen, or impregnating dust of the date, \nhas been found by Fourcroy and Vauquelin to contain \na matter analogous to gluten, and a soluble extract \nabounding in malic acid. Link found in the pollen of \nthe hazel-tree, much tannin and gluten. \n\nSaccharine matter is found in the nectarium of flow- \ners, or the receptacles within the corolla, and by tempt- \ning the larger insects into the flowers, it renders the work \nof impregnation more secure; for the pollen is often by \ntheir means applied to the stigma ; and this is particu- \nlarly the case when the male and female organs are in \ndifferent flowers or different plants. \n\nIt has been stated that the fragrance of flowers de- \npends upon the volatile oils they contain ; and these oils, \nby their constant evaporation, surround the flower with \na kind of odorous atmosphere ; which, at the same time \nthat it entices larger insects, may probably preserve the \nparts of fructification from the ravages of smaller ones. \nVolatile oils, or odorous substances, seem particularly \ndestructive to these minute insects and animalcules \nwhich feed on the substance of vegetables ; thousands \nof aphides may be usually seen in the stalk and leaves \nof the rose but none of them are ever observed in the \nflower. Camphor is used to preserve the collections of \nnaturalists. The woods that contain aromatic oils are \nremarked for their indestructibility ; and for their ex- \nemption from the attacks of insects : this is particularly \nthe case with the cedar, rose- wood, and cypress. The \ngates of Constantinople, which were made of this last \nwood, stood entire from the time of Constantine, their \nfounder, to that of Pope Eugene IV. a period of 1100 \nyears. \n\nThe petals of many flowers afford saccharine and \nmucilaginous matter. The white lily yields mucilage \nabundantly : and the orange lily a mixture of mucilage \nand sugar ; the. petals of the convolvulus afford sugar^, \nmucilage, and albuminous matter. \n\n\n\n104 \n\nThe chemical nature of the colouring matters of flow- \ners has not as yet been subject to any very accurate ob- \nservation. These colouring matters, in general, are very \ntransient, particularly the blues and reds ; alkalies \nchange the colours of most flowers to green, and acids \nto red. An imitation of the colouring matter may be \nmade by digesting solutions of gall-nuts with chalk : \na green fluid is obtained, which becomes red by the ac- \ntion of an acid ; and has its green colour restored by \nmeans of alkalies. \n\nThe yellow colouring matters of flowers are the most \npermanent ; the carthamus contains a red and a yellow \ncolouring matter ; the yellow colouring matter is easily \ndissolved by water, and from the red, rouge is prepared \nby a process which is kept secret. \n\nThe same substances as exist in the solid parts of \nplants are found in their fluids, with the exception of \nAvoody fibre. Fixed and volatile oils containing resin \nor camphor, or analogous substances in solution exist \nin the cylindrical tubes belonging to a number of plants. \nDifferent species of Euphorbia emit a milky juice, which \nwhen exposed to air deposit a substance analogous to \nstarch, and another similar to gluten. \n\nOpium, gum elastic, gamboge, the poisons of the Upas \nAntiar and Tiiite, and other substances that exude from \nplants, may be considered as peculiar juices belonging \nto appropriate vessels. \n\nThe sap of plants, in general, is very compound in \nits nature : and contains most saccharine, mucilaginous, \nand albuminous matter in tlie alburnum ; and most tan- \nnin and extract in the bark. The cambium, which is \nthe mucilaginous fluid found in trees between the wood \nand the bark, and which is essential to the formation of \nnew parts, seems to be derived from these two kinds of \nsap ; and probably is a combination of the mucilaginous \nand albuminous matter of one, with the astringent mat- \nter of the other, in a state fitted to become organized by \nthe separation of its watery parts. \n\nThe alburnous saps of some trees have been chemi- \ncally examined by Vauquelin. He found in those of tlie \nelm, beech, yoke elm, hornbeam and birch, extractive \nand mucilaginous matter, acetic acid combined with po- \ntassa or lime. The solid matter afforded by their cva- \n\n\n\n105 \n\nporatiou yielded an ammouiacal smell, probably owing \nto albumen : the sap of the birch afforded saccharine \nmatter. \n\nDeyeux in the sap of the vine and the yoke elm has \ndetected a matter analogous to the curd of milk. 1 found \na substance similar to albumen in the sap of the walnut \ntree. \n\nI found the juice which exudes from the vessels of \nthe marshmallow when cut, to be a solution of mucilage. \n- The fluids contained in the sap vessels of wheat and \nbarley, afforded in some experiments which I made on \nthem, mucilage, sugar, and a matter which coagulated \nby heat ; which last was most abundant in wheat. \n\nThe following table contains a statement of the quan- \ntity of soluble or nutritive matters contained in varieties \nof the different substances tliat have been mentioned, \nand of some others which are used as articles of food, \neither for man or cattle. The analyses are my own ; \nand were conducted with a view to a knowledge of the \ngeneral nature and quantity of the products, and not of \ntheir intimate chemical composition. The soluble mat- \nters afforded by the grasses, except that from the florin \nin winter, were obtained by Mr. Sinclair, gardener to \nthe Duke of Bedford, from given weights of the grasses \ncut when the seeds were ripe ; they were sent to me by \nhis Grace\'s desire for chemical examination ; and form \npart of the results of an important and extensive series \nof experiments on grasses, made by direction of the \nDuke, at Woburn Abbey, the full details of which I \nshall hereafter have the pleasure of stating. \n\n\n\no \n\n\n\n106 \nTable of the Quantities of sohtble or nutritive Mat- \nters afforded by 1000 Parts of different vegetable \nSubstances, \n\n\n\nVegetables or vegeta- \nble Subhtajice. \n\n\n\nMiddlesex wheat, \n\naverage crop - \xe2\x80\xa2 \n\nSpring wheat - - - - . \n\nMilde\\vedwheatofl806 \n\nBlighted wlieat of 1804 \n\nThick-skinned Sicili- > \n\nan wheat of 1810 3 \n\nThin-skinned Sicili-\'? \n\nan wheat of ISIO 5 \n\nWheat from Poland - - \n\nNorth American wheat \n\nNorfolk barley \n\nOats from Scotland - - \nRje from Yorkshire - - \n\nCommon bean \n\nDry peas --.---..- \n\nPotatoes - \n\n\n\nLinseed cake ...... \n\nRed Beet \n\nWhite Beet \n\nParsnip \n\nCarrots \n\nCommon turnips - . - . \nSwedish turnips - - - - \n\nCabbage \n\nBroad-leaved clover - - \nLong-rooted clover - - \n\n\\Miite clover \n\nSainfoin \n\nLucerne -.--.-... \nMeadow fox-tail grass \nPerennial rye-grass - - \nFertile meadow grass \nKougliish mtadow grass \nCrested dog\'s-tail grass \nSpiked fescue grass \xe2\x80\xa2 \nSweet-scented soft, do. \nDo. do. vernal, do \n\nFiorin -- \n\nFiorin cut in winter - - \n\n\n\na> c 2; \n\n\n\n955 \n\n940 \n210 \n650 \n\n955 \n\n961 \n\n950 \n\n955 \n\n920 \n\n743 \n\n792 \n\n570 \n\n574 \n\n:fr. 260 \n\n\' to 200 \n\n151 \n\n148 \n\n136 \n\n99 \n\n98 \n\n42 \n\n64 \n\n73 \n\n39 \n\n39 \n\n32 \n\n39 \n\n23 \n\n33 \n\n39 \n\n78 \n\n39 \n\n35 \n\n19 \n\n82 \n\n50 \n\n54 \n\n76 \n\n\n\n765 \n\n700 \n178 \n\n520 \n\n725 \n\n\n\n722 \n\n750 \n730 \n790 \n641 \n645 \n426 \n501 \n:fr. 200 \nto 155 \n123 \n\n14 \n\n13 \n9 \n3 \n7 \n9 \n\n41 \n\n31 \n\n30 \n\n29 \n\n28 \n\n18 \n\n24 \n\n26 \n\n65 \n\n29 \n\n28 \n\n15 \n\n72 \n\n43 \n\n46 \n\n64 \n\n\n\n70 \n15 \n38 \n\n22 \n\n:fr. 20 \n\n\'to 15 \n\n11 \n\n121 \n\n119 \n\n90 \n\n95 \n\n34 \n\n51 \n\n24 \n\n3 \n\n4 \n\n1 \n\n2 \n\n1 \n\no \n4 \n6 \n5 \no \n\n2 \n4 \n4 \n5 \n8 \n\n\n\n3 - \n\n\n\n190 \n\n240 \n\n32 \n\n130 \n\n230 \n\n\n\n200 \n\n225 \n\n60 \n\n87 \n\n109 \n\n103 \n\n35 \n\n:fr. 40 \n\n\'to 30 \n\n17 \n\n14 \n\n4 \n\n\n\n107 \n\nAll these substances \\yere submitted to experiment \ngreen, and in their natural states. It is probable that \nthe excellence of the different articles as food will be \nfound to be in a great measure proportional to the quan- \ntities of soluble or nutritive matters they afford ; but \nstill these quantities cannot be regarded as absolutely \ndenoting their value. Albuminous or glutinous matters \nhave the characters of animal substances ; sugar is more \nnourishing, and extractive matter less nourishingj than \nany other principles composed of carbon, hydrogene, \nand oxygene. Certain combinations likewise of these \nsubstances may be more nutritive than others. \n\nI have been informed by Sir Joseph Banks, that the \nDerbyshire miners in winter prefer oatcakes to wheatcn \nbread; finding that this kind of nourishment enables thera \nto support their strength and perform their labour bet- \nter. In summer, they say oat cake heats them, and they \nthen consume the finest wheaten bread they can procure. \nEven the skin of the kernel of oats probably has a \nnourishing power, and is rendered partly soluble in the \nstomach with the starch and gluten. In most countries \nof Europe, except Britain, and in Arabia, horses are fed \nwith barley mixed with chopped straw ; and tiie chop- \nped straw seems to act the same part as the husk of the \noat. In the mill 141bs. of good wheat yield "on an ave- \nrage ISlbs. of flour; the same quantity of barley 12lbs. \nand of oats only 81bs. \n\nIn the south of Europe, hard or thin-skinned wheat \nis in higher estimation, than soft or thick-skinned wheat ; \nthe reason of which is obvious, from the larger quantity \nof gluten and nutritive matter it contains. I have an \nanalysis of only one specimen of thin-skinned wheat, \nso that other specimens may possibly contain more nu- \ntritive matter than that in the Table ; the B.i rhary and \nSicilian wheats, before refer; ed to, were thick sk\'nned \nwheats. In England the difficulty of grinding thin- \nskinned wheat is an objection ; but this difficiiUy is easily \novercome by moistening the corn.* \n\n*For the followinc^ note on the subject I am indebted to the kind- \nness of the Right Hon. Sir Joseph Banks, Bart. K. B. \n\n\n\n1 08 \n\ninjormiiluv.t received from John Jeffrey^ Esq. His Mijestifs \nConsul General at Lisbon, in Ansxvcr to Queries transmitted to \nhim, from the Comm. of P. C, for Trade, dated Jan. 12, 1812, \n\nTo grind hard corn with the mill stones used in England, the wheat \nmust be well screened, tiien sprinkled with water at the nuller\'s dis- \ncretion, and laid in heaps and frequently turned and thoroughly mix- \ned, which will soften the husk so as to make it separate from the flour \nin grinding, and of course give the flour a brighter colour ; other- \nwise the flinty quality of the wheat, and the thinness of the skin will \nprevent its separation, and will render the flour unfit for making into \nbread. \n\nI am informed by a miller of considerable experience, and who \nworks his mills entirely with the stones from England or Ireland, \nthat he frequently prepares the hard Barbary corn by immersing it \nin water in close wicker baskets, and spreading it thinly on a floor to \ndry; much flepends on the judgment and skill of the miller in pre- \nparing the corn for the mill according to its relative quality. I beg \nto observe, that it is not from this previous process of wetting the \ncorn that the weight in the flour of hard corn is increased ; but from \nits natural quality it imbibes considerably more water in making it into \nbread. The mill-stones must not be cut too deep, but the furrows \nvery fine, and picked in the usual way. The mills should work with \nless velocity in grinding hard corn than with soft, and set to work at \nfirst with soft corn, till the mill ceases to work well; then put on the \nhard corn. Hard wheat always sells at a higher price in the market \nthan soft wheat, on an average of ten or fifteen per cent. ; as it pro- \nduces more flour in proportion, and less bran than the soft corn. \n\nFlour made from hard wheat is more esteemed than what is made \nfrom soft corn ; and both sorts are applied to every purpose. \n\nThe flour of hard wheat is in general superior to that made from \nsoft ; and there is no difference in the process of making them into \nbread; but the flour from hard wheat will imbibe and retain more \nwater in making into bread ; and will consequently produce more \nweight of bread : it is the practice here, and which I am persuaded \nit would be advisable to adopt in England, to make bread with flour \nof hard and soft wheat, which by being mixed, will make the bread \nmuch better. \n\n(Signed) JOHN JEFFERY. \n\n\n\nLECTURE IV. \n\nOn Soils : their constituent Parts. On the Analysis of \nSoils. Of the Uses of the Soil. Of the Rocks and \nStrata found beneath Soils. Of the Imjjrovement of \nSoil. \n\nIS subjects are of more importance to the farmer than \nthe nature and improvement of soils; aiul no parts of \nthe doctrines of agriculture are more capable of being \nillustrated by chemical inquiries. \n\nSoils are extremely diversified in appearance and \nquality ; yet as it was stated in the Introductory Lec- \nture, they consist of different proportions of the same \nelements ; which are in various states of chemical com- \nbination, or mechanical mixture. \n\nThe substances which constitute soils have been al- \nready mentioned. Tliey are certain compounds of the \nearths, silica, lime, alumina, magnesia, and of the oxides \nof iron and magnesium ; and animal and vegetable mat- \nters in a decomposing state, and saline, acid or alkaline \ncombinations. \n\nIn all chemical experiments on the composition of soils \nconnected with agriculture, the constituent parts obtained \nare compounds ; and they act as compounds in nature : \nit is in this state, therefore, that 1 shall describe their \ncharacteristic properties. \n\n1. Silica, or the eartli of ^tw#s, in its pure and crys- \ntallized form, is the substance known by the name of \nrock crystal, or Cornish diamond. As it is procured by \nchemists, it appears in the form of a white impalpable \npowder. It is not soluble in the common acids, but dis- \nsolves by heat in fixed alkaline lixivia. It is an incom- \nbustible substance, for it is saturated with oxygene. I \nhave proved it to be a compound of oxygene, and the \npeculiar combustible body which I have named silicum ; \nand from the experiments of Berzelius, it is probable \nthat it contains nearly equal weights of these two ele- \nments. \n\n\n\njlD \n\n2. The sensible properties of lime are well known. \nIt exists in soils usually united to carbonic acid ; which \nis easily disengaged from it by the attraction of the com- \nmon acids. It is sometimes found combined with the \nphosphoric and sulphuric acids. Its chemical proper- \nties and agencies in its pure state will be described in \nthe Lecture on manures obtained from the mineral king- \ndom. It is soluble in nitric and muriatic acids, and \nforms a substance with sulphuric acid, difficult of solu- \ntion, called gypsum. It is not soluble in alkaline solu- \ntions. It consists of one proportion 40 of the peculiar \nmetallic substance, which I have named calcium ; and \none* proportion 15 of oxygene. \n\n3. Mumina exists in a pure and crystallized state in \nthe white sapphire, and united to a little oxide of iron \nand silica in the other oriental gems. , In the state in \nwhich it is procured by chemists, it appears as a white \npowder, soluble in acids and fixed alkaline liquors. \niVom my experiments, it appears that alumina consists \nof one proportion 33 of aluminum, and one 15 of oxy- \ngene. \n\n4. Magnesia exists in a pure crystallized state, con- \nstituting a mineral like talc found in North America. \nIn its common form it is the magnesia usta, or calcined \nmagnesia of druggists. It generally exists in soils com- \nbined with carbonic acid. It is soluble in all the mi- \nneral acids ; but not in alkaline lixivia. It is distinguish- \ned from the other earths found in soils by its ready so- \nlubility in solutions of alkaline carbonates saturated with \ncarbonic acid. It appears to consist of 38 magnesium \nand 15 oxygene. \n\n5. There are two well known oxides of iron, the black \nand the brown. The black is the substance tiiat flies off \nwhen red hot iron is hammered. The brown oxide may \nbe formed by keeping the black oxide red hot, for a long \ntime in contact with air. The first seems to consist of \none proportion of iron 103, and two of oxygene 30 ; and \nand the second of one proportion of iron 103, and three \nproportions of oxygene 45. The oxides of iron some- \ntimes exist in soils combined with carbonic acid. They \nare easily distinguished from other substances by their \ngiving when dissolved in acids a black colour to solu- \n\n\n\nIll \n\ntiou of galls, and a bright blue precipitate to solution of \nprussiate of potassa and iron. \n\n6. The oxide of manganesum is the substance com- \nmonly called manganese, and used in bleaching. It ap- \npears to be composed of one proportion of manganesum \n113, and three of oxygene 45. It is distinguished from \nthe other substances found in soils, by its property of \ndecomposing muriatic acid, and converting it into chlo- \nrine. \n\nVegetable and animal matters are known by their sen- \nsible qualities, and by their property of being decompo- \nsed by heat. Their characters may be learnt from the \ndetails in the last Lecture. \n\n8. The saline compounds found in soils, are common \nsalt, sulphate of magnesia, sometimes sulphate of iron, \nnitrates of lime and of magnesia, sulphate of potassa, \nand carbonates of potassa and soda. To describe their \ncharacters minutely will be unnecessary; the tests, for \nmost of them have been noticed p. 81. \n\nThe silica in soils is usually combined with alumina \nand oxide of iron, or with alumina, lime, magnesia and \noxide of iron, forming gravel and sand of different de- \ngrees of fineness. The carbonate of lime is usually in \nan impalpable form : but sometimes in the state of cal- \ncareous sand. The magnesia, if not combined in the \ngravel and sand of soil, is in a fine powder united to \ncarbonic acid. The impalpable part of the soil, which \nis usually called clay or loam, consists of silica, alumi- \nna, lime, and magnesia ; and is, in fact, usually of the \nsame composition as the hard sand, but more finely di- \nvided. The vegetable, or animal matters, (and the first \nis by far the most common in soils) exist in different \nstates of decomposition. They are sometimes fibrous, \nsometimes entirely broken down and mixed with the \nsoil. \n\nTo form a just idea of soils, it is necessary to conceive \ndifferent rocks decomposed, or ground into parts and \npowder of different degrees of fineness ; some of their \nsoluble parts dissolved by water, and that water adhe- \nring to the mass, and the whole mixed with larger or \nsmaller quantities of the remains of vegetables and ani- \nmals in different stages of decay. \n\n\n\n112 \n\nIt will be necessary to describe the processes by whicli \nall the varieties of soil may be analysed. I shall be mi- \nnute in these particulars, and, I fear, tedious ; but the \nphilosophical farmer will, 1 trust, feel the propriety of \nfull details on this subject. \n\nThe instruments required for the analysis of soils are \nfew, and but little expensive. They are a balance ca- \npable of containing a quarter of a pound of common soil, \nand capable of turning when loaded, with a grain ; a set \nof weights from a quarter of a pound troy to a grain ; a \nwire sieve, sufficiently coarse to admit a mustard seed \nthrough its apertures ; an Argand lamp and stand ; some \nglass bottles ; Hessian crucibles ; porcelain, or queen\'s \nware evaporating basins ; a Wedgewood pestle and \nmortar ; some filtres made of half a sheet of blotting pa- \nper, folded so as to contain a pint of liquid, and greased \nat the edges ; a bone knife, and an apparatus for col- \nlecting and measuring aeriform fluids. \n\nThe chemical substances or reagents required for se- \nparating the constituent parts of the soil, have, for the \nmost part, been mentioned before : they are muriatic acid \n{spirit of salt,) sulphuric acid, pure volatile alkali dis- \nsolved in water, solution of prussiate of potash and iron, \nsuccinate of ammonia, soap lye, or solution of potassa, \nsolutions of carbonate of ammonia, of muriate of ammo- \nnia, of neutral carbonate of potash, and nitrate of ammo- \nniac. \n\nIn cases when the general nature of the soil of a field \nis to be ascertained, specimens of it sliould be taken from \ndifferent places, two or three inches below the surface,, \nand examined as to the similarity of their properties. It \nsometimes happens, that upon plains the whole of the \nupper stratum of the land is of the same kind, and in \nthis case, one analysis will be sufficient; but in valleys, \nand near the beds of rivers, there are very great differ- \nences, and it now and then occurs that one part of a field \nis calcareous, and another part siliceous ; and in this \ncase, and in analogous cases, the portions different from \neach other should be separately submitted to experi- \nment. \n\nSoils when collected, if they cannot be immediately \nexamined, should be preserved in phials quite filled with \nthem, and closed with ground glass stoppers. \n\n\n\n113 \n\nThe quantity of soil most convenient for a perfect \nanalysis, is from two to four hundred grains. It should \nbe collected in dry weather, and exposed to the atmos- \nphere till it becomes dry to the touch. \n\nThe specific gravity of a soil, or the relation of its \nweight to that of water, may be ascertained by introdu- \ncing into a phial, which will contain a known quantity \nof water, equal volumes of water and of soil, and this \nmay be easily done by pouring in water till it is half full, \nand then adding the soil till the fluid rises to the mouth; \nthe difterence between the weight of tiie soil and that \nof the water, will give the result. Thus if the bottle \ncontains four hundred grains of water, and gains two \nliundred grains when half filled with water and half \nwith soil, the specific gravity of the soil will be 2, that \nis, it will be twice as heavy as water, and if it gained \none hundred and sixty-five grains, its specific gravity \nwould be 1825, water being 1000. \n\nIt is of importance, that the specific gravity of a soil \nshould be known, as it affords an indication of the quan- \ntity of animal and vegetable matter it contains ; these \nsubstances being always most abundant in the lighter \nsoils. \n\nThe other physical properties of soils should likewise \nbe examined before the analysis is made, as they de- \nnote, to a certain extent, their composition, and serve as \nguides in directing the experiments. Thus siliceous \nsoils are generally rough to the touch, and scratch glass \nwhen rubbed upon it; ferruginous soils are of a red or \nyellow colour ; and calcareous soils are soft. \n\n1 . Soils, though as dry as they can be made by con- \ntinued exposure to air, in all cases still contain a con- \nsiderable quantity of water, which adiieres with great \nobstinacy to the earths and animal and vegetable mat- \nter, and can only be driven off from them by a consi- \nderable degree of heat. The first process of analysis \nis, to free the given weight of soil from as much of this \nwater as possible, without in other respects, affecting its \ncomposition ; and this may be done by heating it for ten \nor twelve minutes over an Argand\'s lamp, in a basin of \nporcelain, to a temperature equal to 300 Fahrenheit ; \nand if a thermometer is not used, the proper degree \n\n\n\n114 \n\nmay be easily ascertained, by keeping a piece of wood \nin contact with tlie bottom of the dish ; as long as the \ncolour of tlie wood remains unaltered, the heat is not \ntoo high ; hut when the wood begins to be cliarred, the \nprocess must lie stopped. A small quantity of water \nwill perhaps remain in the soil even after this operation, \nbut it always atlbrds useful comparaiive results ; and if \na higher temperature were emplo^yed, the vegetable or \nanimal matter would undergo deufrrrposition, and in \nconsequence the experiment be wholly unsatisfactory. \n\nThe loss of \\\\ eight in the process should be carefully \nnoted, and when in four hundred grains of soil it \nreadies as high as 50, the soil may be considered as in \nthe greatest degree absorbent, and retentive of water, \nand will generally be found to contain much vegetable \nor animal matter, or a large proportion of aluminous \nearth. When the loss is only from 20 to 10, the land \nmay be considered as only slightly absorbent and reten- \ntive, and siliceous earth probably forms the greatest \npart of it. \n\n2. None of the loose stones, gravel, or large vegeta- \nble fibres should be divided from the pure soil till after \nthe water is drawn oft\'; for these bodies are themselves \noften highly absorbent and retentive, and in consequence \ninfluence the fertility of the land. The next process, \nhowever, after that of heating, should be their separa- \ntion, which may be easily accomplished by the sieve, \nafter the soil has been gently bruised in a mortar. The \nweights of the vegetable fibres or wood, and of the gra- \nvel and stones should be separately noted down, and \nthe nature of the last ascertained ; if calcarious, they \nwill efl\'ervesce with acids; if siliceous, they will be suf- \nficiently hard to scratch glass ; and if of the common \naluminous class of stones, they w ill be soft, easily cut \nwith a knife, and incapable of effervescing with acids. \n\n3. The greater number of soils, besides gravel and \nstones, contain larger or smaller proportions of sand of \ndifferent degrees of fineness ; and it is a necessary ope- \nration, the next in the process of analysis, to detach \nthem from the parts in a state of more minute division, \nsuch as clay, loam, marie, vegetable and animal matter, \nand the matter, soluble in w ater. This mav be ett\'ected \n\n\n\n115 \n\niu a vvny suiRciently accurate by Ijoiliiig tlie soil in lliree \nor four times its vveiglit of water; aud vvlieii the texture \nof the soil is broken down, and the water cool ; by agi- \ntating the parts together, and then suflVring tiiem to rest. \nIn this case, the coarse sand will generally separate in \na minute, and the finer in two or three minutes, whilst \nthe highly divided earthy, animal, or vegetable matter \nwill remain in a state of mechanical suspension for a \nmuch longer time; so that by pouring the water from \nthe bottom of the vessel, after one, two, (u* three minutes, \nthe sand will be principally separated from the other \nsubstances, which, with the water containing them, must \nbe poured into a filtre, and after the water has passed \nthrough, collected, dried, and weighed. The sand must \nlikewise be weighed, and the respective quantities noted \ndown. The water of lixiviaticui must be preserved, as \nit will be found to contain the saline and soluble animal \nor vegetable matters, if any exist in the soil. \n\n4. By the process of washing and filtration, the soil \nis separated into two portions, the most important of \nwhich is generally the finely divided matter. A minute \nanalysis of the sand is seldom or never necessary, and \nits nature may be detected in the same manner as that \nof the stones or gravel. It is always either siliceous \nsand, or calcareous sand, or a mixture of both. ]f it \nconsist wholly of carljonate of lime, it will be rapidly \nsoluJde in muriatic acid, with effervescence ; Jjut if it \nconsist partly of this substance, and partly of siliceous \nmatter, the resjiective cpiantities may be ascertained by \nweighing the residuum after the action of the acid, \nwhich must be applied till the mixture has accjuired a \nsour taste, and has ceased to effervesce. This residuum \nis the siliceous part : it must be washed, dried and heat- \ned strongly in a crucible ; the difference between the \nweight of it and the weight of the whole, indicates the \nproportion of calcareous sand. \n\n5. The finely divided matter of the soil, is usually \nvery compound in its nature ; it sometimes contains all \nthe four primitive earths of soil, as well as animal and \nvegetable matter ; and to ascertain the proportions of \nthese with tolerable accuracy, is the most difficult part \nof the subject. \n\n\n\n\'VUv liisi pi\'ocess to be pcrlbrmetl, in this part of the \nanal;\\His. is the exposure of the fine matter of the soil \nto tlie adioii of muriatic aciil. This substance should \nbe poured upon the eartliy matter in an evaporating ba- \nsin, in a qiinniity equal to twice the weight of the earthy \nmatter; but diluted with double its volume of water. \nThe mixture should be often stirred, and suftered tore- \nmain for au hour or an hour and a half, before it is ex- \namined. \n\nIf any carbounte of lime or of magnesia exist in the \nsoil, tiiey will IsaNe been dissolved in this time by the \nacid, w hicji sometimes takes up likewise a little oxide \nof iron : but very seldom any alumina. \n\nThe tluid should be passed through a filtre ; the solid \nmatter collected washed with rain water, dried at a mo- \nderate heat and weighed. Its loss will denote the quan- \ntity of solid matter taken up. The washings must be \nadded to the solution, which if not sour to the taste, \nmust be made so by the addition of fresh acid, when a \nlittle solution of prussiate of potassa and iron, must be \nmixed with tlie whole. If a l)lue precipitate occurs, it \ndenotes the presence of oxide of iron, and the solution \nof the prussiate must be dropped in till no farther eftect \nis produced. To ascertain its quantity, it must be col- \nlected in the same manner as other solid precipitates, and \nheated red ; the result is oxide of iron, which may be \nmixed witli a little oxide of manganesum. \n\nInto the fluid freed from oxide of iron, a solution of \nneutralized carbonate of potash must be poured till all \neflervescence ceases in it, and till its taste and smell in- \ndicate a considerable excess of alkaline salt. \n\nThe precipitate that tails down is carbonate of lime; \nit must I)e collected on the filtre, and dried at a heat be- \nlow that of redness. \n\nThe remaining fluid must be boiled for a quarter of \nan hour, Avhen the magnesia, if any exist, will be pre- \ncipitated from it, combined with carbonic acid, and its \nquantity is to be ascertained in the same manner as \nthat of the carbonate of lime. \n\nIf {iny minute proportion of alumina should, from pe- \nculiar circumstances, be dissolved by the acid, it will be \nfound in the precipitate with the carbonate of lime, and \n\n\n\n117 \n\nit may be separated from it by boiling it lor a few mi- \nnutes with soap lye, sufficient to cover the solid matter; \nthis siibstance dissolves alumina, without acting upon \ncarbonate of lime. \n\nShould the finely divided soil be sufficiently calcare- \nous to eflervesce very strongly with acids, a very simple \nmethod may be adopted for ascertaining the quantity of \ncarbonate of lime and one sufficiently accurate in all \ncommon cases. \n\nCarbonate of lime, in all its states, contains a deter- \nminate proportion of carbonic acid, i. e. nearly 43 per \ncent, so that when the quantity of this elastic fluid, gi- \nven out by any soil during tlie solution of its calcareous \nmatter in an acid is known, either in weight or mea- \nsure, the quantity of carbonate of lime may be easily \ndiscovered. \n\nWhen the process by diminution of weight is em- \nployed, two parts of the acid and one part of the matter \nof the soil must be weighed in two separate bottles, and \nvery slowly mixed together till the eJQPervescence ceases ; \nthe dijfference between their weight before and after the \nexperiment, denotes the quantity of carbonic acid lost ; \nfor every four grains and a quarter of which, ten grains \nof carbonate of lime must be estimated. \n\nThe best method of collecting the carbonic acid, so \nas to discover its volume, is by a peculiar pneumatic ap- \nparatus,* in which its hulk may be measured by the \nquantity of water it displaces. \n\n* Fig. 15. A, B, C, D, represent the different parts of tliis appar- \natus. A. Represents tlie bottle for receiving the soil. B. \'I\'he bot- \ntle containing the acid, furnished with a stop-cock. C. The tube \nconnected with a flaccid bladder. D. The graduated measure. E. \nThe bottle for containing the bladder. When this instrument is \nused, a given quantity of soil is introduced into A. B ib fiiied witti \nmuriatic acid diluted with an equal quantity of water; and the stop- \ncock being closed, is connected with the upper orifice of A, which is \nground to receive it. Tlie tube D is introduced into the lower ori- \nfice of A, and the. bladder connected wiih it placed in its flaccid state \ninto E. which is fiiied with water. The graduated measure is placed \nunder the tube of E. When the stop-cock of B is turned, the acid \nflows into A, and acts upon the soil ; the elastic fluid generated \npasses through C into the bladder, and displaces a quantity of water \nin E equal to it in bulk, and this water flows through the tube into \nthe graduated measure: and gives by its volume the indication of the \nproportion of carbonic acid disengaged from the soil ; for every ounce \nmeasure of which two grains of carbonate of lime may be estimated. \n\n\n\n118 \n\n6. After tlie calcareous parts of the soil has been act- \ned upon by muriatic acid, tlie uext process is to ascer- \ntaiu tlic quantity of finely divided insoluble animal and \nvegetable matter that it contains. \n\nlliis may be done with sufficient precision, by strong- \nly igniting it in a crucible over a common fire till no \nblackness remains in the mass. It should be often stir- \nred with a metallic rod, so as to expose new surfaces \ncontinually to the air ; the loss of weight that it under- \ngoes denotes the quantity of the substance that it con- \ntains destructible by fire and air. \n\nIt is not possible, without very refined and difficult \nexperiments, to ascertain whether this substance is whol- \nly animal or vegetable matter, or a mixture of both. \nWhen the smell emitted during the incineration is simi- \nmilar to that of burnt feathers, it is a certain indication \nof some substance either animal or analogous to animal \nmatter ; and a copious blue flame at the time of ignition, \nalmost always denotes a considerable proportion of ve- \ngetable matter. In cases when it is necessary that the \nexperiment should be very quickly performed, the de- \nstruction of the decomposable substances may be assist- \ned by the agency of nitrate of ammoniac, which at the \ntime of ignition may be thrown gradually upon the heat- \ned mass in the quantity of twenty grains for every hun- \ndred of residual soil. It accelerates the dissipation of \nthe animal and vegetable matter, which it causes to be \nconverted into elastic fluids ; and it is itself at the same \ntime decomposed and lost. \n\n7. The substances remaining after the destruction of \nthe vegetable and animal matter, are generally minute \nparticles of earthy matter, containing usually alumina \nand silica, with combined oxide of iron or of mangane- \nsum. \n\nTo separate these from each other, the solid matter \nshould be boiled for two or three hours with sulphuric \nacid, diluted with four times its weight of water ; the \nquantity of the acid should be regulated by the quanti- \nty of solid residuum to be acted on, allowing for every \nhundred grains, two drachms or one hundred and twen- \nty grains of acid. \n\nThe substance remaining after the action of the acid. \n\n\n\n1 19 \n\nmay bu consickred as siliceous ; and it must be separa- \nted and its wei^^ht ascertained, after washini^ and dry- \ning in tiie usual manner. \n\nTbe alumina and tlie oxide of iron and manganesum, \nif any exist, are all dissolved by the sulpluiric acid ; \nthey may be separated by succinate of ammonia, added \nto excess ; which throws down the oxide of iron, and \nby soap lye, which will dissolve the alumina, but not \nthe oxide of manganesum : the weights of theoxides as- \ncertained after they have been heated to redness will de- \nnote their quantities. \n\nShould any magnesia and lime have escaped solution \nin the muriatic acid, they will be found in the sulphuric \nacid : this, however, is rarely the case ; but the process \nfor detecting them, and ascertaining their quantities, is \nthe same in both instances. \n\nThe method of analysis by sulphuric acid, is suffi- \nciently precise for all. usual experiments ; but if very \ngreat accuracy be an object, dry carbonate of potassa \nmust be employed as the agent, and the residuum of the \nincineration (6) must be heated red for a half hour, with \nfour times its weight of this substance, in a crucible of \nsilver, or of well baked porcelain. The mass obtained \nmust be dissolved in miaiatic acid, and the solution \nevaporated till it is nearly solid ; distilled water must \nthen be added, by which the oxide of iron and all the \nearths, except silica, will be dissolved in combination \nas muriates. The silica, after the usual process of lixi- \nviation, must be heated red ; the other substances may \nbe separated in the same manner as from the muriate \nand sulphuric solutions. \n\nThis process is the one usually employed by chemi- \ncal philosophers for the analysis of stones. \n. 8. If any saline matter, or soluble vegetable or ani- \nmal matter is suspected in the soil, it will be found in \nthe water of lixiviation used for separating the sand. \n\nThis water must be evaporated to dryress in a pro- \nper dish, at a heat below its boiling point. \n\nIf the solid matter oI)tained is of a brown colour and \ninflammable, it may be considered as partly vegetable \nextract. If its smell, when exposed to heat, be like \nthat of burnt feathers, it contains animal or albuminous \n\n\n\n120 \n\nluaLlcr; if it Ui." while, crystalliiic, and not dcslructihli \nhy iicat, it may he cousitlciTtl as |)riiuu|>all,Y saline mat- \nivv; llic naluio of uliich may he known by tlic tests \n(lesniheil pa^r 81, \n\n9. Shonld snlpliate or pliospliate of lime ho snspect- \nC(l in the entire soil, Ihe delection of tlieni requires a \nparticnhir i)ro( ess upon it. A i:;iven \\veii;ht of il, for in- \nstance, four huiulred i^rains, nuist he heated red for lialf \nan hour in a i rut ihU\xc2\xbb, mixed with oue-tinrd of powder- \ned (harcoal. The mixture must l>e hoiU\'d fora([uarter \nof an hour, in a half pint of water, and the thiid col- \nlected (hrouj;i\xc2\xbb the filtre, and exposed for some days to \ntlie almospliere in an open vessel. If any notable (pnm- \ntity of sul[)hate of lime (i;ypsum) existed in the soil, a \nwhile precipitate will i;ra<lually form in the iluid, and \ntin\xc2\xbb weii;ht of it will indicate the proportion. \n\nl*hos[)ha(e of lime, if any exist, may he separated from \nthe soil after Ihe process IVu" i;ypsum. Mnrialic acid \nmust be digested upon the soil, in ([uantity more than \nsnflicient to salurale the soluble earths ; Ihe solution must \nbe evaporatetl, and waler poure\xc2\xabl upon the soTul matter. \nThis Iluid w ill dissolve the (impounds of earths with \nthe muriatic acid, and leave the phosphate of lime un- \ntouched. \n\nIt would not fall within the limits assi:;ned to this \nLecture, to detail any processes for the detection of sub- \nstances which may be accidentally mixed with the mat- \nters of soils. Other earths and metallic oxides are now \nand then found in them, but in (piantities too minute to \nbear anv relation to fertilitv or barrenness, and the search \nfor them would make the analysis much more complica- \nted without renderiiii; it nnue useful. \n\n10. When the examination of a soil is conqdeled, the \nproducts should be numerically arrani;ed, and their \n(piantities adiled toi;ether, and if they nearly equal the \norii;inal <iuantily of soil, the analysis may be consider- \ned as accurate. It must, however, be noticed, that when \n[)lu)sphate or sulphate of lime are discovered by Ihe in- \ndepeu\xc2\xbblent process just \xc2\xbblescribed, (i>.) a ct)rrection must, \nbe nuule l\\tr the i;eneral process, by subtractinj:; a sum \necpial to their wei:;ht from the <|uantily of carbonate of \nlin\\e, ohtaimMl by precipitation from the muriatic acid. \n\n\n\n121 . \n\nTii arraiii^ing the products, the rorin should be in tiic \norder of llie exporimiMits l>y wliich ihvy were, procured. \n\nThus, 1 obtained from 401) i^rains of a p)od siliceous \nsandy soil from a bop garden near Tunbridge, Kent, \n\n(i rains. \n\nOf water of absorption - - - - 19 \n\nOf loose stones and i:;ravel principally siliceous 53 \n\nOf undecompounded vej^etable fibres - - 14 \n\nOf fine siliceous sand ----- 212 \nOf minutely divided matter se|)arated by agitation \nand filtration, and consisting of \n\nCarbonate of lime 19 \n\nCarbonate of magnesia . . . . 3 \nMatter destructible by beat, principally vegeta- \nble 15 \n\nSilica ------- 21 \n\nAlumina 13 \n\nOxide of iron ------ 5 \n\nSoluble matter, principally common salt and vege- \ntable extract - _ - , . 3 \nGypsum 2 \n\n\n\nAmount of all the products 379 \nLoss - - - - 21 \n\n\n\nThe loss in this analysis is not more than usually oc- \ncurs, and it depetids upon the impossibility of collect- \ning the whole (piantities of the jliflerent precipitates; \nand upon the presence of more moisture than is account- \ned for in the water of absorption, and which is lost in \nthe difl\'erent processes. \n\nWhen the experimenter is become acquainted witli \nthe use of the dilferent instruments, the jiroperties of the \nreagents, and the relations betwcien the> external and \nchemical qualities of soils, he will seldom find it neces- \nsary to perform, in any one case, all tin; processes that \nhave been descril\xc2\xbbed. When his soil, for instance, con- \ntains no notable pro|)ortion of calcareous matter, the ac- \ntion of the muriatic acid (7) may be omitted. In exam- \nining peat soils, he will principally have to attend to the \noperation by fire and air (8 ;) and in the analysis of \n\nQ \n\n\n\n122 \n\nchalks a\'lul loams, lie will often be able to omit the ex- \nperiment by sulphuric acid (9.) \n\nIn the first trials that are made by persons unacquaint- \ned with chemistry, they must not expect much precision \nof result. Many difficulties will be met with : but in \novercomiug tliem, the most useful kind of practical know- \nledge will he ohtained ; and nothing is so instructive in \nexperimentjjl science, as the detection of mistakes. The \ncorrect analyst ougiit to be well grounded in general \nchemical information ; but perhaps there is no better \nmode of gaining it, than that of attempting original in- \nTestigations. In pursuing his experiments he will be \ncontinually obliged to learn the properties of the sub- \nstances he is employing or acting upon ; and his theo- \nretical ideas will be more valuable in being connected \nwith practical operations, and acquired for the purpose \nof discovery. \n\nPlants being possessed of no locomotive powers, can \ngrow only in places where they are supplied with food; \nand the soil is necessary to their existence, both as af- \nfording them nourishment, and enabling them to fix them- \nselves in such a manner as to obey those mechanical \nlaws by which their radicles are kept below the surface, \nand their leaves exposed to the free atmosphere. As \nthe systems of roots, branches and leaves are very dif- \nferent in difterent vegetables, so they flourish most in \ndiflerent soils, the plants that have bulbous roots require \na looser and a lighter soil than such as have fibrous \nroots ; and the plants possessing only short fibrous radi- \ncles demand a firmer soil than such as have tap roots, \nor extensive lateral roots. \n\nA good turnip soil from Holkham, Norfolk, afforded \nme eight parts out of nine silicious sand ; and the fine- \nly divided matter consisted \n\nOf Carbonate of lime - - 63 \n\n\xe2\x80\x94 Silica - - - - 15 \n\n\xe2\x80\x94 Alumina - - - - 11 \n\n\xe2\x80\x94 Oxide of iron . . - 3 \n\n\xe2\x80\x94 Vegetable and saline matter 5 \n\n\xe2\x80\x94 Moisture . . . - - 3 \n\n\n\n128 \n\nI found the soil taken from a iiekl at Sheffield-place \nin Sussex, remarkable for producing flourishing oaks, to \nconsist of six parts of sand, and one part of clay and \nfinely divided matter. And one hundred parts of the \nentire soil submitted to analysis, produced \n\nParts. \n\nSilica - - - - 54 \n\nAlumina - - - - 28 \n\nCarbonate of lime - - 3 \n\nOxide of iron - - - - 5 \n\nDecomposing vegetable matter 4 \n\nMoisture and loss - - 3 \n\nAn excellent wheat soil from the neighbourhood of \nWest Drayton, Middlesex, gav\xc2\xab three parts in five of \nsilicious sand ; and the finely divided matter consist- \ned of \n\nCarbonate of lime - - - 28 \nSilica - - - - - 32 \nAlumina - - - - 29 \n\n\n\nAnimal or vegetable matter and \nmoisture \n\n\n\n11 \n\n\n\nOf these soils the last was by far the most, and the \nfirst the least, coherent in teiiLture. In all cases the con- \nstituent parts of the soil which give tenacity and cohe- \nrence are the finely divided matters ; and they possess \nthe power of giving those qualities in the highest degree \nwhen they contain much alumina. A small quantity of \nfinely divided matter is sufficient to fit a soil for the pro- \nduction of turnips and barley ; and I have seen a tole- \nrable crop of turnips on a soil containing 11 parts out \nof twelve sand. A much greater proportion of sand \nhowever, always produces absolute sterility. The soil \nof Bagshot heath, which is entirely devoid of vegeta- \nble covering, contains less than ^V of finely divided mat- \nter. 400 parts of it, which had been lieated red, afford- \ned me 380 parts of coarse siliceous sand ; 9 parts of fine \nsiliceous sand, and 11 parts of impalpable matter, which \nwas a mixture of ferruginous clay, with carbonate of lime. \nVegetable or animal matters, when finely divided, not \n\n\n\nonly give coherence, but likewise softness and penetia- \nbility ; but neither they nor any other part of the soil \nmust he in too great proportion ; and a soil is uopro- \nductive if it consist entirely of impalpable matters. \n\nPure alumina or silica, pure carboi\\atc of lime, or \ncarbonate of magnesia, are incapable of supporting heal- \nthy vegetation. \n\nNo soil is fertile that contains as much as 19 parts \nout of 20 of any of the constituents that have been men- \ntioned. \n\nIt Avill be asked, are the pure earths in the soil mere- \n.ly active as mechanical or indirect chemical agents, or \ndo they actually afford food to the plant ? This is an \nimportant question ; and not tlifficult of solution. \n\nThe earths consist^ as 1 have before stated, of me- \ntals united to oxygene ; and these metals have not been \ndecomposed ; there is consequently no reason to suppose \nthat the earths are convertible into the elements of or- \nganized compounds, into carbon, hydrogene, and azote. \n\nPlants have been made to grow in given quantities of \nearth. They consume very small portions only ; and \nwhat is lost may be accounted for by the quantities found \nin their ashes ; that is to say, it has not been converted \ninto any new products. \n\nThe carbonic acid united to lime or magnesia, if any \nstronger acid happens to be formed in the soil during \nthe fermentation of vegetable matter which will disen- \ngage it from the earths, may be decomposed ; but the \nearths themselves cannot be supposed convertible into \nother substances, by any, process taking place in the \nsoil. \n\nIn all cases the ashes of plants contain some of the \nearths of the soil in which they grow; but these earths, \nas may be seen from the table of the ashes afforded by \ndifferent plants given in the last Lecture, never equal \nmore than A of the weight of the plant consumed. \n\nIf they be considered as necessary to the vegetable, \nit is as giving hardness and firmness to its organization. \nThus, it has been mentioned that wheat, oats, and ma- \nny of the hollow grasses, have an epidermis principally \nof siliceous earth ; the use of which seems to be to \n\n\n\n125 \n\nstrengthen them, and defend them from the attacks of \nof insects and parasitical plants. \n\nMany soils are popiilarl j distinguished as cold ; and \nthe distinction, though at first view it may appear to he \nfounded on prejudice, is really just. \n\nSome soils are much more heated by the rays of the \nsun, all other circumstances being equal, than others ; \nand soils brought to the same degree of heat cool in dif- \nferent times, i. e. some cool much faster than others. \n\nThis property has been very little attended to in a \nphilosophical point of view ; yet it is of the highest im- \nportance in agriculture. In general, soils that consist \nprincipally of a stiff white clay are difficultly heated ; \nand being usually very moist, they retain their heat on- \nly for a short time. Chalks are similar in one respect, \nthat they are difficultly heated ; but being drier they re- \ntain their heat longer, less being consumed in causing \nthe evaporation of their moisture. \n\nA black soil, containing mucli soft vegetable matter, \nis most heated by the sun and air ; and the coloured \nsoils, and the soils containing much carbonaceous mat- \nter, or ferruginous matter, exposed under equal circum- \nstances to sun, acquire a much higher temperature than \npale-coloured soils. \n\nWhen soils are perfectly dry, those that most readi- \nly become heated by the solar rays likewise cool most \nrapidly ; but 1 liave ascertained by experiment, that the \ndarkest coloured dry soil (that which contains abun- \ndance of animal or vegetable matter ; substances which \nmost facilitate the diminution of temperature,) when heat- \ned to the same degree, provided it be within the common \nlimits of the effect of solar heat, will cool more slowly \nthan a wet pale soil, entirely composed of earthy matter. \n\n1 found tliat a ricli black mould, which contained near- \nly \\ of vegetable matter, had its temperature increased \nin an hour from 65^^ to 88^ by exposure to sunshine ; \nwhilst a chalk soil was heated only to 69^ under the \nsame circumstances. But the mould removed into the \nshade, wliere the temperature was 62\xc2\xb0, lost, in half an \nhour, 15\xc2\xb0 ; whereas the chalk, under the same circum- \nstances, had lost only 4\xc2\xb0. \n\nA brown fertile soil, and a cold barren clay were each \n\n\n\n126 \n\nartificially heated to 88\xc2\xb0, having beeu previously dried : \nthey were then exposed in a temperature of 57\xc2\xb0; in half \nan hour the dark soil was found to have lost 9\xc2\xb0 of heat ; \nthe clay had lost only 6\xc2\xb0. An equal portion of the clay \ncontaining moisture, after being heated to 88\xc2\xb0, was ex- \nposed in a temperature of 55\xc2\xb0 ; in less than a quarter of \nan hour it was found to have gained the temperature of \nthe room. The soils in all these experiments were pla- \nced in small tin plate trays two inches square, and half \nan inch in depth ; and tlie temperature ascertained by a \ndelicate thermometer. \n\nNothing can be more evident, than that the genial \nheat of the soil, particularly in spring, must be of the \nhighest importance to the rising plant. And when the \nleaves are fully developed, the ground is shaded ; and \nany injurious influence, M\'hicli in the summer might be \nexpected from too great a heat, entirely prevented : \nso that the temperature of the surface, when bare and \nexposed to the rays of the sun, aflbrds at least one indi- \ncation of the degrees of its fertility ; and the thermo- \nmeter may be sometimes a useful instrument to the pur- \nchaser or improver of lands. \n\nThe moisture in the soil influences its temperature ; \nand the manner in which it is distributed through, or \ncombined with, the earthy materials, is of great impor- \ntance in relation to the nutriment of the plant. If wa- \nter is too strongly attracted by the earths, it will not be \nabsorbed by the roots of the plants : if it is in too great \nquantity, or too loosely united to them, it tends to in- \njure or destroy the fibrous parts of the roots. \n\nThere .are two states in which water seems to exist \nin the earths, and in animal and vegetable substances : \nin the first state it is united by chemical, in the other by \ncohesive, attraction. \n\nIf pure solution of ammonia or potassabe poured into \na solution of alum, alumina falls down combined with \nw^ater : and the powder dried by exposure to air will \naftbrd more than half its weight of water by distilla- \ntion ; in this instance the water is united by chemical \nattraction. The moisture which wood, or muscular \nfibre, or gum, that have been heated to 212\xc2\xb0, afford by \ndistillation at a red heat, is likewise water, the elements \n\n\n\n127 \n\nof wliich were united in the substance by chemical com- \nbination. \n\nWhen pipe-clay dried in the temperature of the at- \nmosphere is brought in contact with water, the fluid is \nrapidly absorbed ; this is owing to cohesive attraction. \nSoils in general, vegetable, and animal substances, that \nhave been dried at a heat below that of boiling water, \nincrease in weight by exposure to air, owing to their ab- \nsorbing water existing in the state of vapour in the air, \nin consequence of cohesive attraction. \n\nThe water chemically comhined amongst the elements \nof soils, unless in the case of the decomposition of ani- \nmal or vegetable substances, cannot be absorbed by the \nroots of plants ; but that adhering to the parts of the \nsoil is in constant use in vegetation. Indeed there are \nfew mixtures of the earths found in soils, that contain \nany chemically combined water; water is expelled from \nthe earths by most substances that combine with them. \nThus, if a combination of lime and water be exposed \nto carbonic acid, the carbonic acid takes the place of \nwater ; and compounds of alumina and silica, or other \ncompounds of the earths, do not chemically unite with \nwater : and soils, as it has been stated, are formed either \nby earthy carbonate*^, or compounds of the pure earths \nand metallic oxides. \n\nWhen saline substances exist in soils, they may be \nunited to water both chemically and mechanically ; but \nthey are always in too small a quantity to influence ma- \nterially the relations of the soil to water. \n\nThe power of the soil to absorb water by cohesive \nattraction, depends in great measure upon the state of \ndivision of its parts ; the more divided they are, the \ngreater is their absorbent power. The dift\'erent con- \nstituent parts of soils likewise appear to act, even by \ncohesive attraction, with different degrees of energy. \nThus vegetable substances seem to be more absorbent \nthan animal substances ; animal substances more so than \ncompounds of alumina and silica ; and compounds of \nalumina and silica more absorbent than carbonates of \nlime and magnesia: these diflferences may, however, \npossibly depend upon the differences in theirstate of di- \n\\ision, and upon the surface exposed. \n\n\n\n128 \n\nThe power of soils to absorb water from air, is much \nconnected with fertility. When this power is great, \nthe plant is supplied with moisture in dry seasons; and \nthe effect of evaporation in the day is counteracted by \nthe absorption of aqueous vapour from the atmosphere, \nby the interior parts of the soil during the day, and by \nboth the exterior and interior during night. \n\nThe stiff clays approaching to pipe-clays in their na- \nture, which take up the greatest quantity of water when \nit is poured upon them in a fluid form, are not the soils \nwhich absorb most moisture from the atmosphere in dry \nweather. They cake, and present only a small surface \nto the air ; and the vegetation on them is generally burnt \nup almost as readily as on sands. \n\nThe soils that are most efficient in supplying the plant \nwith water by atmospheric absorption, are those in which \nthere is a due mixture of sand, finely divided clay, and \ncarbonate of lime, with some animal or vegetable mat- \nter : and wiiich are so loose and light as to be freely \npermeable to the atmosphere. With respect to this \nquality, carbonate of lime and animal and vegetable \nmatter are of great use in soils ; they give absorbent \npower to the soil without giving U likewise tenacity : \nsand, which also destroys tenacity, on the contrary, \ngives little absorbent power. \n\nI have compared the absorbent powers of many soils \nwith respect to atmospheric moisture, and I have always \nfound it greatest in the most fertile soils ; so that it af- \nfords one method of judging of the productiveness of \nland. \n\n1000 parts of a celebrated soil from Ormiston, in \nEast Lothian, w hich contained more than half its weight \nof finely divided matter, of which 11 parts were car- \nbonate of lime, and nine parts vegetable matter, when \ndried at 212^*, gained in an hour by exposure to air sa- \nturated with moisture, at temperature 62\xc2\xb0, 18 grains. \n\nlOOO\'parts of a very fertile soil from the banks of the \nriver Parret, in Somersetshire, under the same circum- \nstances, gained 16 grains. \n\n1000 parts of a soil from Mersea, in Essex, worth \n45 shillings an acre, gained 1-3 grains. \n\n\n\n129 \n\n1000 grains of a fine sand from Essex, worth 28 shil- \nlings an acre, gained 11 grains. \n\n1000 of a coarse sand worth 15 shillings an acre, \ngained only eight grains. \n\n1000 of the soil of Bagshot-heath gained only three \ngrains. \n\nWater, and the decomposing animal and viigetahle \nmatter existing in the soil, constitute the true nourish- \nment of plants ; and as the earthy parts of the soil are \nuseful in retaining water, so as to suj)ply it in the proper \nproportions to the roots of the vegetables, so they arc \nlikewise eflBcacious in producing the proper distribution \nof the animal or vegetable matter ; when equally mixed \nwith it they prevent it from decomposing too rapidly ; \nand by their means the soluble parts are supplied in \nproper proportions. \n\nBesides this agency, which may be considered as me- \nchanical, there is another agency between soils and or- \nganizable matters, which may be regarded as chemical \nin its nature. The earths, and even the earthy carbo- \nnates, have a certain degree of chemical attraction for \nmany of the principles of vegetable and animal substan- \nces. This is easily exemplified in the instance of alu- \nmina and oil ; if an acid solution of alumina be mixed \nwith a solution of soap, which consists of oily matter \nand potassa; the oil and the alumina will unite and \nform a white powder, which will sink to the bottom of \nthe fluid. \n\nThe extract from decomposing vegetable matter when \nboiled with pipe-clay or chalk, forms a combination by \nwhich the vegetable matter is rendered more difficult \nof decomposition and of solution. Pure silica and sili- \nceous sands have little action of this kind ; and the soils \nwhich contain the most alumina and carbonate of lime are, \nthese which act with the greatest chemical energy in pre- \nserving manures. Such soils merit the appellation which \nis commonly given to them of rich soils; for the vegeta- \nble nourishment is long preserved in them, unless taken \nup by the organs of plants. Siliceous sands, on the \ncontrary, deserve the term hungry, wliich is commonly \napplied to them ; for the vegetable and animal matters \nthey contain not being attracted by the earthy constitu- \n\nR \n\n\n\n130 \n\nml; parts of the soil, arc more liable to be decomposed \nb.y the action of the atmosphere, or carried oil\' from them \nby M aler. \n\ni II most of ihe black and brown rich vegetable moulds, \nthe earths seem to be in combination with a peculiar ex- \ntractive matter, alVorded during the decomposition of ve- \n2;etables : tiiis is slowly taken up, or attracted from the \nearths by water, and appears to constitute a prime cause \nof the fertility of the soil. \n\nThe staiuhu-d of fertility of soils for different plants \nmust vary with the climate; and must be particularly \ninlluenced by the quantity of rain. \n\n\'J he power of soils to absorb moisture ought to be \nmuch greater in \\> arm or dry counties, than in cold and \nmoist ones ; and the (piantity of clay, or vegetable or \nanimal matter they contain greater. Soils also on de- \nclivities ought to be more absorbent than in i>lains or in \nthe bottom of vallies. Their pnuluctiveness likewise \nis inlluenced by the nature of the subsoil or the stratum \non which they rest. \n\n\\V hen soils are immediately situated upon a bed of \nrock or stone, they are much sooner rendered dry by \nevaporation, than wiiere the subsoil is of clay or marie; \nand a prime cause of liie great fertility of the land in \ntlse moist climate of Ireland, is the proximity of the \nrocky strata to the soil. \n\nA clayey subsoil will sometimes be of material advan- \ntage to a sandy soil ; and in this case it w ill retain mois- \nture in such a manner as to be capable of supplying that \nlost by the earth above, in consequence of evaporation, \nor the consumption of it by plants. \n\nA sandy, or gravelly suhsoil, often corrects the im- \nperfections of too great a degree of absorbent poMer in \nthe true soil. \n\nIn calcareous countries, where the surface is a spe- \ncies of marie, the soil is often found only a few inches \nabove the limiestone; and its fertility is not impaired by \nthe proximity of the rock ; though in a less absorbent \nsoil, this situation would occasion barrenness ; and the \nsandstone and limestone hills in Derbyshire and North \nWales, may be easily distinguished at a distance in \nsummer ])y the different tints of the vegetation. The \n\n\n\n131 \n\ngrass on the sandstone hills usually appears brown and \nImrnt up; that on the limestone hills liourishinti; and \ngreen. \n\nIn devoting the diflerent parts of an estate to the ne- \ncessary crops, it is perfectly evident from what has been \nsaid, that no general principle can be laid down, except \nwhen all the circumstances of the nature, composition, \nand situation of the soil and subsoil are known. \n\nThe methods of cultivation likewise must be dift\'er- \nent for different soils. The same practice which will \nbe excellent in one case may be destructive in ano- \nther. \n\nDeep ploughing may be a very profitalile practice in \na rich thick soil ; and in a fertile shallow soil, situated \nupon cold clay or sandy subsoil, it may be extremely \nprejudicial. \n\nIn a moist climate where the (juantity of rain that \nfalls annually equals from 40 to 60 inches, as in Lanca- \nshire, Cornwall, and some parts of Ireland, a siliceous \nsandy soil is much more productive than in dry districts; \nand in such situations, wheat and beans will re(|uire a \nless coherent and absorlient soil than in drier situations ; \nand plants having bulbous roots, will llourish in a soil \ncontaining as much as 14 parts out of 15 of sand. \n\nEven the exhausting powers of crops will be influen- \nced by like circumstances. In cases where plants can- \nnot absorb sufficient moisture, they must take up more \nmanure. And in Ireland, Cornwall, and the western \nHighlands of Scotland, corn will exhaust less than in \ndry inland situations. Oats, particularly in dry climates, \nare impoverishing in a much higlier degree than in moist \nones. \n\nSoils appear to have been originally produced in con- \nsequence of the decomposition of rocks and strata. It \noften happens that soils are found in an unaltered state \nupon the rocks from which they were derived. It is \neasy to form an idea of the manner in which rocks are \nconverted into soils, by referring to the instance of soft \ngranite, or jwrcelain granite. This substance consists \nof three ingredients, quartz, feldspar, and mica. The \nquartz is almost pure silicious earth, in a crystalline \nform. The feldspar and mica are very compounded sub- \n\n\n\nstances ; Iiotli contain silica, alumina, and oxide of iron ; \nin the IVldsjiar there is usually lime and potassa: in the \nmica, lime and magnesia. \n\nW\'iien a granitic rock of tliis kind has been long ex- \nposed to the intluencc of air and water, tlie lime and the \npotassa contained in its constituent parts are acted upon \nby water or carbonic acid ; and the oxide of iron, which \nis almost always in its least oxided state, tends to com- \nbine with more oxygene ; the consequence is, tliat the \nfeldspar decomposes, and likewise the mica; l)ut the first \nthe most rapidly. The felds|)ar, which is as it were the \ncement of the stone, forms a tine clay: the mica partial- \nly decomposed mixes with it as sand; and thcundecom- \n])osed (|uart/- appears as gravel, or sand of different de- \ngrees of fuK\'ness. \n\nAs soon as the smallest layer of earth is formed on the \nsurface of a rock, the seeds of lichens, mosses, and \nother imperfect vegetables which are constantly floating \nin the atmosphere, ami which have made it their rest- \ning place, begin to vegetate; their death, decomposition, \nand decay, afford a certain quantity of organizable mat- \nter, which mixes with the earthy materials of the rock ; \nin this improved soil more perfect plants are capable of \nsubsisting ; these in their turn absorb nourishment from \nwater and the atmosphere ; and after perishing, afford \nnew materials to those already provided : the decomposi- \ntion of the rock still continues ; and at length by such \nslow and gradual processes, a soil is formed in which even \nforest trees can fix their roots, and which is fitted to re- \nward the labours of the cultivator. \n\nIn instances wiiere successive generations of vegeta- \nbles have grown upon a soil, unless part of their pro- \nduce has been carried off by man, or consumed by ani- \nmals, the vegetable matter increases in such a propor- \ntion, that the soil approaches to a peat in its nature ; \nand if in a situation where it can receive water from a \nhigher district, it becomes spongy, and permeated with \nthat fluid, and is gradually rendered incapable of sup- \nporting the nobler classes of vegetables. \n\nMany peat- mosses seem to have been formed by the \ndestruction of forests, in consequence of the imprudent \nuse of the hatchet by the early cultivators of the conn- \n\n\n\ntry ill wliich they exist: when the trees are felled in the \nout-skirts of a wood, those in the interior exposed to the \ninfluence of the winrls ; and havini:; been accustomed to \nshelter, become unhealthy, and die in their new situa- \ntion ; and their leaves and branches gradually decora- \nj)osing, produce a stratum of vegetable matter. In ma- \nny of the great bogs in Ireland and Scotland, the larger \ntrees that are found in the out-skirts of them, bear the \nmarks of having been felled. In the interior few en- \ntire trees are found ; and the cause is, probably, that \nthey fell by gradual decay ; and that the fermentation \nand decomposition of the vegetable matter was most ra- \npid where it was in the greatest quantity. \n\nLakes and pools of water are sometimes filled up by \nthe accumulation of the remains of aquatic plants ; and \nin this case a sort of spurious peat is formed. The fer- \nmentation in these cases, however, seems to be of a dif- \nferent kind. Much more gaseous matter is ev(dved ; \nand the neighbourhood of morasses in which aquatic ve- \ngetables decompose, is usually aguish and unhealthy ; \nwhilst that of the true peat, or peat formed on soils ori- \nginally dry, is always salubrious. \n\nThe earthy matter of peats is uniformly analogous to \nthat of the stratum on which they repose ; the plants \nwhich have formed them must have derived the earths \nthat they contained from this stratum. Thus in Wilt- \nshire and Berkshire, where the stratum below the peat \nis chalk, calcareous earth abounds in the ashes, and ve-. \nry little alumina or silica. They likewise contain much \noxide of iron and gypsum, ])oth of which may be deri- \nved from the decomposition of the pyrites, so abundant \nin chalk. \n\nDifferent specimens of peat that I have burnt from \nthe granitic and schistose soils of different parts of these \nislands, have always given ashes principally siliceous \nand aluminous ; and a specimen of peat from the coun- \nty of Antrim, gave ashes which afforded very nearly \ntlie same constituents as the great basaltic stratum of the \ncounty. \n\nPoor and hungry soils, such as are produced frOm the \ndecomposition of granitic and sandstone rocks, remain \nvery often for ages with only a thin covering of vegeta- \n\n\n\n134 \n\ntioii. Soils from the decomposition of limestone, chalks, \nand basaltsj are often clothed by nature with the peren- \nnial grasses ; and afford, when ploughed up, a rich bed \nof vegetation for every species of cultivated plant. \n\nHocks and strata from which soils have been derived, \nand those which compose the more interior solid parts \nof the globe, are arranged in a certain order ; and as it \noften happens that strata very different in their nature \nare associated together, and that the strata immediately \nbeneath the soil contain materials which may be of use \nfor improving it, a general view of the nature and posi- \ntion of rocks and strata in nature, will not, I trust, be \nunacceptable to the scientific farmer. \n\nKocks are generally divided by geologists into two \ngrand division\'s, distinguished by the names of primary \nand secondary. \n\nThe primary rocks are composed of pure crystalline \nmatter, and contain no fragments of other rocks. \n\nThe secondary rocks, or strata, consist only partly of \ncrystalline matter ; contain fragments of other rocks or \nstrata ; often abound in the remains of vegetables and \nmarine animals ; and sometimes contain the remains of \nland animals. \n\nThe primary rocks are generally arranged in large \nmasses, or in layers vertical, or more or less inclined to \nthe horizon. \n\nThe secondary rocks are usually disposed in strata \nor layers, parallel, or nearly parallel to the horizon. \n\nThe number of primary rocks which are commonly \nobserved in nature are eight. \n\nFirst, granite, which as has been mentioned, is compo- \nsed of quartz, feldspar, and mica; when these bodies are \narranged in regular layers in the rock, it is called gneis. \n\nSecond, micaceous schistiiSf which is composed of \nquartz and mica arranged in layers, which are usually \ncurvilineal. \n\nThird, sienite, which consists of the substance called \nhornblende and feldspar. \n\nFourth, serpentine, which is constituted by feldspar \nand a body named resplendent hornblende ; and their \nseparate crystals are often so small as to give the stone \na uniform appearance : this rock abounds in veins of a \nsubstance called steatite, or soap rock. \n\n\n\n135 \n\nFifth, porphyry f which consists of crystals of feldspai\' \nembedded in the same material, but usually of a difl\'er- \nent colour. \n\nSixth, graiiular marble, which consists entirely of \ncrystals of carbonate of lime ; and which, when its co- \nlour is white, and texture fine, is the substance used by \nstatuaries. \n\nSeventh, chlorite schist, which consists of chlorite, a \ngreen of gray substance somewhat analogous to mica \nand feldspar. \n\nEight, qiiartzose rock, which is composed of quartz \nin a granular form sometimes united to small quantities \nof the crystalline elements, which have been mentioned \nas belonging to the other rocks. \n\nThe secondary rocks are more numerous than the pri- \nmary ; but twelve varieties include all that are usually, \nfound in these islands. \n\nFirst, graiiwacke, which consists of fragments of \nquartz, or chlorite schist, embedded in a cement, prin- \ncipally composed of feldspar. \n\nSecond, siliceous sandstone, which is composed of \nfine quartz or sand, united by a siliceous cement. \n\nThird, limestone, consisting of carbonate of lime, \nmore compact in its texture than in the granular mar- \nble ; and often abounding in marine exuvia. \n\nFourth, aluminous schist or shale, consisting of the \ndecomposed materials of diflFerent rocks cemented by a \nsmall quantity of ferruginous or siliceous matter ; and \noften containing the impressions of vegetables. \n\nFifth, calcareous sandstone, which is calcareous sand, \ncemented by calcareous matter. \n\nSixth, iron stone, formed of nearly the same mate- \nrials as aluminous schist, or shale ; but containing a \nmuch larger quantity of oxide of iron. \n\nSeventh, basalt or whinstone, which consists of feld- \nspar and hornblende, with materials derived from the \ndecomposition of the primary rocks ; the crystals are \ngenerally so small as to give the rock a homogeneous \nappearance ; and it is often disposed in very regular \ncolumns, having usually five or six sides. \nEighth, bituminous or common coal. \nNinth, gypsum^ the substance so well known by that \n\n\n\n136 \n\nname, which consists of sulphate of lime ; and often \ncontains sand. \n\nTenth, rock salt. \n\nEleventh, vhalk, whicli usually abounds in remains of \nmarine animals, and contains horizontal layers of flints. \n\nTwelfth plum-pudding stone, consisting of pebbles \ncemented by a ferruginous or siliceous cement. \n\nTo describe more particularly the constituent parts of \nthe difl\'erent rocks and strata will be unnecessary : at \nany time, indeed, details on this subject are useless, un- \nless the specimens are examined bythe!eye; and a close \ninspection and comparison of the different species, will, \nin a short time, enable the most common observer to dis- \ntinguish them. \n\nTlie highest mountains in these islands, and indeed \nin the whole of the old continent, are constituted by \ngranite ; and this rock has likewise been found at the \ngreatest depths to which the industry of man has as yet \nbeen able to penetrate ; micaceous schist is often found \nimmediately upon granite ; serpentine or marble upon \nmicaceous schist : but the order in which the primary \nrocks are grouped together is various. Marble and \nserpentine are usually found uppermost; but granite, \nthough it seems to form the foundation of the rocky \nstrata of the globe, is yet sometimes discovered above \nmicaceous schist. \n\nTlie secondary rocks are always incumbent on the \nprimary ; the lowest of them is usually grauwacke : \nupon this, limestone or sandstone is often found ; coal \ngenerally occurs between sandstone or shale ; basalt of- \nten exists above sandstone and limestone ; rock salt al- \nmost always occurs associated with red sandstone and \ngypsum. Coal,\' basalt, sandstone and limestone, are \noften arranged in different alternate layers, of no con- \nsiderable thickness, so as to form a great extent of coun- \ntry. In a depth of less than 500 yards, 80 of these \ndifferent alternate strata have been counted. \n\nThe veins which afford metallic substances, are fis- \nsures more or less vertical, filled with a material differ- \nent from the rock in which they exist. \'Jliis material \nis almost always crystalline ; and usually consists of \ncalcareous spar, ttuor spar, quartz, or heavy spar either \n\n\n\n137 \n\nseparate or together. The metallic substances are ge- \nnerally dispersed through, or confusedly mixed with \nthese crystalline bodies. The veins in hard granite sel- \ndom afford much useful metal ; but in the veins in soft \ngranite, and in gneis, tin, copper, and lead are found. \nCopper and iron are the only metals usually found in \nthe veins in serpentine. Micaceous schist, sienite, and \ngranular^marble, are seldom metalliferous rocks. Lead, \ntin, copper, iron, and many otlier metals are found in \nthe veins in chlorite schist. Grauwacke, when it con- \ntains few fragments and exists in large masses, is often \na metalliferous rock. The precious metals, likewise \niron, lead, and antimony, are found in it ; and sometimes \nit contains veins or masses of stone coal, or coal free \nfrom bitumen. Limestone is the great metalliferous rock \nof the secondary family ; and lead and copper are the \nmetals most usually found in it. No metallic veins \nhave ever been found in shale, chalk or calcareous sand- \nstone; and they are very rare in basalt and silicious \nsandstone.* \n\nIn cases where veins in rocks are exposed to the at- \nmosphere, indications of the metals they contain may be \noften gained from their superficial appearance. When- \never iluor\' spar is found in a vein, there is always strong \nreason to suspect that it is associated with metallic sub- \nstances. A brown powder at the surface of a vein al- \nways indicates iron, and often tin ; a pale yellow pow- \nder lead ; and a green colour in a vein denotes the pre- \nsence of copper. \n\nIt may not be improper to give a general description \nof the geological constitution of Great Britain and L\'e- \nland. Granite forms the great ridge of hills extending \nfrom Land\'s End through Dartmoor into Devonshire. \nThe highest rocky strata in Somersetshire are grau- \nwacke and limestone. The Malvern hills are compo- \nsed of granite sienate and porphyry. The highest moun- \ntains in Wales are chlorite schist, or grauwacke. Gra- \nnite occurs at Mount Sorrel in Leicestershire. The \ngreat range of the mountains in Cumberland and West- \n\n* Fig. 1 6, will give a general idea of the appearance and arrange- \nment of rocks and veins. \n\n\n\nLSS \n\nniorelniiil. ;uc poiphyvy, chlorite, schist, and grauwacke; \nbut iijranUc is tVmiul at the western boundary. Through- \nout Scotland tlie most elevated rocks are granite, sienite, \nand micaceous scliistus. No true secondary formations \nare found in South Britain, west of Dartmoor ; and no \nbasalt south of the Severn. The chalk district extends \nfrom the western part of Dorsetshire, to the eastern coast \nof Norfolk. The coal formations abound in the district \nbetween Glamorganshire and Derbyshire; and likewise \nin the secondary strata of Yorkshire, Durham, West- \nmoreland, and Northumberland. Serpentine is found \nonly in three places in Great Britain ; near Cape Li- \nzard in Cornwall, Portsoy in Aberdeenshire, and in \nAyrshire. Black and gray granular marble is found \nnear Padstow in Cornwall ; and other coloured prima- \nry marbles exist in the neighbourhood of Plymouth. \nColoured primary marbles are abundant in Scotland ; \nand white granular marble is found in the Isle of Sky, \nin Assynt, and on the banks of Loch Shin in Suther- \nland : the principal coal formations in Scotland, are in \nDumbartonshire, Ayrshire, Fifeshire, and on the banks \nof the Brora in Sutherland. Secondary limestone and \nsandstone are found in most of the low countries north \nof the Mendip hills. \n\nIn Ireland there are five great associations of prima- \nry mountains ; the mountains of Morne in the county of \nDown; the mountains of Donegal; those of Mayo and \nGalway, those of Wicklow, and those of Kerry. The \nrocks composing the four first of these mountain chains \nare principally granite, gneis, sienite, micaceous schist, \nand porphyry. The mountains of Kerry are chiefly \nconstituted by granular quartz, and chlorite schist. Co- \nloured marble is found near Killarney; and white mar- \nble on the western coast of Donegal. \n\nLimestone and Sandstone are the common secondary \nrocks found south of Dublin. In Sligo, Roscommon, \nand Leitrim, limestone, sandstone, shale, iron stone, and \nbituminous coal are found. The secondary hills in these \ncounties are of considerable elevation ; and many of them \nhave basaltic summits. The northern coast of Ireland \nis principally basalt ; this rock commonly reposes upon \na white limestone, containing layers of flint, and the \nsame fossils as chalk ; but it is considerably harder than \n\n\n\n139 \n\nthat rock. There are some instances, in this district, \nin which columnar basalt is found above sandstone and \nshale, alternating with coal. The stone coal of Ireland \nis principally found in Kilkenny, associated with lime- \nstone and grauwacke. \n\nIt is evident from what has been said concerning the \nproduction of soils from rocks, that there must be at least \nas many varieties of soils as there are species of rocks \nexposed at the surface of the earth ; in fact there are \nmany more. Independent of the changes produced by \ncultivation and the exertions of human labour, the ma- \nterials of strata have been mixed together and transport- \ned from place to place by various great alterations that \nhave taken place in the system of our globe, and by the \nconstant operation of water. \n\nTo attempt to cla\'s"? soils with scientific accuracy would \nbe a vain labour; the distinctions adopted by farmers are \nsufficient for the purposes of agriculture ; particularly if \nsome degree of precision be adopted in the application \nof terms. The term sandy, for instance, should never \nbe applied to any soil that does not contain at least se- \nven-eighths of sand ; sandy soils that eifervesce with \nacids should be distinguished by the name of calcareous \nsandy soil, to distinguish them from those that are sili- \nceous. The term clayey soil should not be applied to \nany land which contains less than one-sixth of impalpa- \nble earthy matter, not considerably effervescing with \nacids ; the word loam should be limited to soils, contain- \ning at least one-third of impalpable earthy matter, copi- \nously effervescing with acids. A soil to be considered \nas peaty, ought to contain at least one-half of vegetable \nmatter. \n\nIn cases where the earthy part of a soil evidently con- \nsists of the decomposed matter of one particular rock, a \nname derived from the rock may with propriety be ap- \nplied to it. Thus, if a fine red earth be found imme- \ndiately above decomposing basalt, it may be denomina- \nted basaltic soil. If fragments of quartz and mica be \nfound abundant in the materials of the soil, which is \noften the case, it may be denominated granitic soil ; and \nthe same principles may be applied to other like in- \nstances. \n\nIn general, the ^oils, the materials of which are the \n\n\n\nt40 \n\nmost various iiud hetevogeueous, are those called alluvi- \nal, or which have been formed from the depositions of \nrivers ; many of tliem are extremely fertile. 1 have ex- \namined some productive alluvial soils, which have been \nvery different in their composition. The soil which has \nbeen mentioned pai;e 128, as very productive, from the \nbanks of tlie river Parret in Somersetshire, afforded me \neight parts of finely divided earthy matter, and one part \nof siliceous sand ; and an analysis of the finely divided \nmatter gave the following results. \n\n360 parts of carbonate of linie. \n\n25 alumina. \n\n20 silica. \n\n8 oxide of iron.^ \n\n19 vej^etable, animal, and saline mat- \nter. \n\nA rich soil from the neighbourhood of the Avon in the \nvalley of Evesham in Worcestershire, afforded me three- \nfifths of fine sand, and two-fifths of impalpable matter ; \nthe impalpable matter consisted of \n\n35 Alumina. \n\n41 Silica. \n\n14 Carbonate of lime. \n\n3 Oxide of iron. \n\n7 Vegetable, animal, and saline matter. \n\nA specimen of good soil from Tiviot-dale, afforded \nfive-sixths of fine siliceous sand, and one-sixth of im- \npalpable matter which consisted of \n\n41 Alumina. \n\n42 Silica. \n\n4 Carbonate of lime. \n\n5 Oxide of iron. \n\n8 Vegetable, animal, and saline matter. \n\nA soil yielding excellent pasture from the valley of \nthe Avon, near Salisbury, afforded one- eleventh of coarse \nsiliceous sand; and the finely divided matter consisted \nof \n\n\n\n141 \n\n7 Alumina. \n14 Silica. \n\n63 Carbonate of lime. \n2 Oxide of iron. \n^ 14 Vegetable, animal, and saline matter. \n\nIn all these instances the fertility seems to depend \nupon the state of division, and mixture of the earthy \nmaterials and the vegetable and animal matter ; and \nmay be easily explained on the principles which 1 have \nendeavoured to elucidate in the preceding part of this \nLecture. \n\nIn ascertaining the composition of sterile soils with a \nview to their improvement, any particular ingredient \nwhich is the cause of their unproductiveness, should \nbe particularly attended to; if possible, they should be \ncompared with fertile soils in the same neighbourhood, \nand in similar situations, as the difference of the com- \nposition may, in many cases, indicate the most proper \nmethods of improvement. If on washa sterile soil it \nis found to contain the salts of iron, or any acid \nmatter, it may be ameliorated by the application of \nquick lime. A soil of good apparent texture from \nLincolnshire, was put into my hands by Sir Joseph \nBanks as remarkable for sterility : on examining it, I \nfound that it contained sulphate of iron ; and I offer- \ned the obvious remedy of top dressing with lime, which \nconverts the sulphate into a manure. If there be an \nexcess of calcareous matter in the soil, it may be im- \nproved by the application of sand, or clay. Soils too \nabundant in sand are benefited by the use of clay, or \nmarie, or vegetable matter. A field belonging to Sir \nRobert Vaughan at Nannau, Merionethshire, the soil of \nwhich was a light sand, was much burnt up in the sum- \nmer of 1805 ; I recommended to that gentleman the ap- \nplication of peat as a top dressiiig. The experiment \nwas attended with immediate good effects ; and Sir Ro- \nbert last year informed me, that the benefit was perma- \nnent. A deficiency of vegetable or animal matter must \nbe supplied by manure. An excess of vegetable mat- \nter is to be removed by burning, or to be remedied by \nthe application of earthy materials. The improvement \n\n\n\n142 \n\nor peats, ov bogs, ov marsli land^, must be i)icce(ie(l by \ndraiiiiiij;" ; sta^^iiaut water beiiij; injurious to all the nu- \ntritive classes of plants. Hoft black peats, when drain- \ned, are often made productive by the mere application \nof sand or clay as a top dressing;. When peats arc \nacicl, or contain ferrujijinous salts, calcareous matter is \nabsolutuely necessary in brini^iiii;; them into cultivation. \nWhen they abiuind in the l>ranches and roots of trees, \nor when their surface entirely consists of living vegeta- \nbles, the wood or the vegetables must either be carried \noff, or }>e destroyed by burning. In the last case their \nashes allcu\'d eartiiy ingredients, fitted to improve the tex- \nture of the peat. \n\nThe best natural soils are those of which the materi- \nals have been derived from difl\'erent strata; which have \nbeen minutely \xc2\xbblivitle\xc2\xbbl by air and water, and arc inti- \nmately blended together : and in improving soils artifi- \ncially, the farmer ( annot do better than imitate the pro- \ncesses of nature. \n\nThe materials necessary for the purpose are seldom \nfar distant : coarse sand is often found immediately on \nchalk ; and beds (\xc2\xbbf sand and gravel are common below \nclay. The labour of improving the texture or constitu- \ntion of the soil, is repaid l)y a great permanent advan- \ntage ; less manure is required, and its fertility insured : \nami capital laid out in this way secures for ever, the pro- \nductiveness, and consequently the value of the land. \n\n\n\nLECTURE V. \n\nOn the J\\rature and Constittition of the Atmosphere ; and \nits Influence on Vegetables. Of the Germination of \nSeeds. Of the Functions of IHants in their differ - \nent Stages of Growth ; with a general View of the \nProgress of Vegetation. \n\nL HE constitution of the atmosphere has heen already \ngenerally referred to in tlic preceding Lectures. Water, \ncarbonic acid gas, oxygene, and azote, have been men- \ntioned as the principal substances composing it ; but more \nminute inquiries respecting tlieir nature and agencies are \nnecessary to afford correct views of the uses of the at- \nmosphere in vegetation. \n\nOn tliese inquiries 1 now propose to enter ; the pur- \nsuit of them, 1 hope, will offer some objects of practical \nuse in farming ; and present some philosophical illustra- \ntions of the manner in which plants are nourished; their \norgans unfolded, and their functions developed. \n\nIf some of the salt called muriate of lime that has \nbeen just heated red be exposed to the air, even in the \ndriest and coldest weather, it will increase in weight \nand become moist ; and in a certain time will be con- \nverted into a fluid. If put into a retort and heated, it \nwill yield pure water ; will gradually recover its pris- \ntine state ; and, if heated red, its former weight : so that \nit is evident, that the water united to it was derived from \nthe air. And that it existed in the air in an invisible \nand elastic form, is proved by the circumstance, that if \na given quantity of air be exposed to the salt, its volume \nand weight will diminish, provided the experiment be \ncorrectly made. \n\nThe quantity of water which exists in air, as vapour, \nvaries with the temperature. In proportion as the wea- \nther is hotter, the quantity is greater. At 50" of Fah- \nrenheit air contains about one fiftieth of its volume of \nvapour 5 and as the specific gravity of vajiour is to that \n\n\n\n144 \n\nof air nearly as 10 to 15, this is about one-seventy-fiftli \nof its weight. \n\nAt 100\xc2\xb0, supposing that there is a free communica- \ntion with water, it contains about one fourteenth parts \nin volume, or one- twenty-first in weight. It is the con- \ndensation of vapour by diminution of the temperature \nof the atmosphere, which is probably the principal cause \nof the formation of clouds, and of the deposition of dew, \nmist, snow, or hail. \n\nThe power of different substances to absorb aqueous \nvapour from the atmosphere by cohesive attraction was \ndiscussed in the last Lecture. The leaves of living \nplants appear to act upon the vapour likewise in its elas- \ntic form, and to absorb it. Some vegetables increase in \nAveight from this cause, when suspended in the atmos- \nphere and unconnected with the soil ; such are the house- \nleek, and different species of the aloe. In very intense \nheats, and when the soil is dry, the life of plants seems \nto be preserved by the absorbent power of their leaves : \nand it is a beautiful circumstance in the economy of na- \nture, that aqueous vapour is most abundant in the at- \nmosphere when it is most needed for the purposes of life ; \nand that when other sources of its supply are cut off, \nthis is most copious. \n\nThe compound nature of water has been referred to. \nIt may be proper to mention the experimental proofs of \nits decomposition into, and composition from, oxygene \nand hydrogene. \n\nIf the metal called potassium be exposed in a glass \ntube to a small quantity of water, it will act upon it \nwith great violence ; elastic fluid will be disengaged, \nwhich will be found to be hydrogene ; and the same ef- \nfects will be produced upon the potassium, as if it had \nabsorbed a small quantity of oxygene ; and the hydro- \ngene disengaged, and the oxygene added to the potas- \nsium are in weight as two to 15 ; and if two in volume \nof hydrogene, and one in volume of oxygene, which have \nthe weights of two and 15, be introduced into a close \nvessel, and an electrical spark passed through them, \nthey will inflame and condense into 17 parts of pure \nwater. \n\nIt is evident from the statements given in the third \n\n\n\n145 \n\nLecture, that water forms by far the greatest part of the \nsap of plants ; and that this substance, or its elements, \nenters largely into the constitution of their organs and \nsolid productions. \n\nWater is absolutely necessary to the economy of ve- \ngetation in its elastic and fluid state ; and it is not de- \nvoid of use even in its solid form. Snow and ice are \nbad conductors of heat ; and when the ground is cover- \ned with snow, or the surface of the soil or of water is \nfrozen, the roots or bulbs of tlic plants beneath are pro- \ntected by the congealed water from the influence of the \natmosphere, the temperature of which in northern win- \nters is usually very much below the freezing point ; and \nthis water becomes the first nourishment of the plant in \nearly spring. The expansion of water during its con- \ngelation, at which time its volume increases one-twelfth, \nand its contraction of bulk during a thaw, tend to pul- \nverise the soil ; to separate its parts from eacli other, \nand to made it more permeable to the influence of the air. \n\nIf a solution of lime in water be exposed to the air, \na pellicle will speedily form upon it, and a solid matter \nwill gradually fall to the bottom of the water, and in a \ncertain time the water will become tasteless ; this is ow- \ning to the combination of the lime, which was dissol- \nved in the water, with carbonic acid gas which existed \nin the atmosphere, as may be proved by collecting the \nfilm and the solid matter, and igniting them strongly in \na little tube of platina or iron ; they will give off car- \nbonic acid gas, and will become quicklime, which add- \ned to the same water, will again bring it to the state of \nlime water. \n\nThe quantity of carbonic acid gas in the atmosphere \nis very small. It is not easy to determine it with pre- \ncision, and it must differ in different situations ; but \nwhere there is a free circulation of air, it is probably \nnever more than one-five hundredth, nor less than one- \neight hundredtli of the volume of air. Carbonic acid \ngas is nearly one-third heavier than the other elastic \nparts of the atmosphere in their mixed state : hence at \nfirst view it might be supposed tiiat it would be most \nabundant in the lower regions of the atmosphere ; but \nunless it has been immediately produced at the surface \n\n\n\n146 \n\nof the earth ill some chemical process, this does not \nseem to he the case : elastic iluids of different speciiic \ngravities have a tendency to equahle mixture by a spe- \ncies of attraction, and the different parts of the atmos- \nphere are constantly agitated and blended together by \nwinds or other causes. . I)e Saussure found lime water \nprecipitated on Mount Blanc, the highest point of land \nin Europe ; and carbonic acid gas has been "always \nfound, apparently in due proportion, in the air brought \ndown from great heights in the atmosphere by aerostatic \nadventurers. \n\nThe experimental proofs of the composition of car- \nbonic acid gas are very simple. If 13 grains of well \nburnt charcoal be inflamed by a burning-glass in 100 \ncubical inches of oxygene gas, the charcoal will entirely \ndisappear : and provided the experiment be correctly \nmade, all the oxygene except a few cubical inches, will \nbe found converted into carbonic acid ; and what is very \nremarkable, the volume of the gas is not changed. On \nthis last circumstance it is easy to found a correct esti- \nmation of the quantity of pure charcoal and oxygene \nin carbonic acid gas : the weight of 100 cubical inches \nis to that of 100 cubical inches of oxygene gas, as 47 \nto 34 : so that 47 parts in weight of carbonic acid gas, \nmust be composed of 34 parts of oxygene and, 13 of \ncharcoal, which correspond with the numbers given in \nthe second Lecture. \n\nCarbonic acid is easily decomposed, by heating potas- \nsium in it ; the metal combines with the oxygene, and \nthe charcoal is deposited in the form of a black powder. \n\nThe principal consumption of the carbonic acid in \nthe atmosphere, seems to be in affording nourishment \nto plants ; and some of them appear to be supplied with \ncarbon chiefly from this source. \n\nCarbonic acid gas is formed during fermentation, com- \nbustion, putrefaction, respiration, and a number of ope- \nrations taking place upon the surface of the earth ; and \nthere is no other process known in nature by which it \ncan be destroyed but by vegetation. \n\nAfter a given portion of air has been deprived of \naqueous vapour and carbonic acid gas, it appears little \naltered in its properties: it suppoi-ts combustion and an i- \n\n\n\n147 \n\nwal life. There are many ijiodes of separating its prin- \ncipal constituents, oxygene and azote, from each other. \nA simple one is by burning phosphorus in a confined \nvolume of air : this absorbs the oxygene and leaves the \nazote; and 100 parts in volume of air, in which phos- \nphorus has been burnt, yield 79 parts of azote : and by \nmixing this azote with 21 parts of fresh oxygene gas \nartificially procured, a substance having the original \ncharacters of air is produced. To procure pure oxy- \ngene from air, quicksilver may be kept heated in it, at \nabout 600\xc2\xb0, till it becomes a red powder ; this powder, \nwhen ignited, will be restored to the state of quicksilver \nby giving off oxygene. \n\nOxygene is necessary to some functions of vegeta- \nbles ; but its great importance in nature is in its relation \nto the economy of animals. It is absolutely necessary \nto their life. Atmospheric air taken into the lungs of \nanimals, or passed 4n solution in water through the gills \nof fishes, loses oxygene ; and for the oxygene lost, about \nan equal volume of carbonic acid appears. \n\nThe effects of azote in vegetation are not distinctly \nknown. As it is found in some of the products of ve- \ngetation, it may be absorbed by certain plants from the \natmosphere. It prevents the action of oxygene from \nbeing too energetic, and serves as a medium in which \nthe more essential parts of the air act ; nor is this cir- \ncumstance unconformable to the analogy of nature; for \nthe elements most abundant on the solid surface of the \nglobe, are not those which are the most essential to th& \nexistence of the living beings belonging to it. \n\nThe action of the atmosphere on plants differs at dif- \nferent periods of their growth, and varies with the va- \nrious stages of the development and decay of their or- \ngans ; some general idea of its influence may have been \ngained from circumstances already mentioned ; I shall \nnow refer to it more particularly, and endeavour to \nconnect it with a general view of the progress of vege- \ntation. \n\nIf a healthy seed be moistened and exposed to air at \na temperature not below 45\xc2\xb0, it soon germinates; it \nshoots forth a plume which rises upwards^ and a raiU- \ncle which descends* \n\n\n\n14B \n\nIf the ai? be confined, it is found that in the process \nof germination the oxygene, or a part of it is absorbed. \nThe azote remains unaltered ; no carbonic acid is ta- \nken away from tlie air, on the contrary some is added. \n\nSeeds are incapable of germinating, except when oxy- \ngcne is present. In tlie exhausted receiver of the air- \npump, in pure azote, in pure carbonic acid, when mois- \ntened they swell, but do not vegetate : and if kept in \nthese gases, lose their living powers and undergo putre- \nfaction. \n\nIf a seed be examined before germination, it will be \nfound more or less insipid, at least not sweet ; but af- \nter germination it is always sweet. Its coagulated mu- \ncilage, or starcli, is converted into sugar in the process ; \na substance difficult of solution is changed into one easily \nsoluble : and the sugar carried through the cells or ves- \nsels of the cotyledons, is the nourishment of the infant \nplant. It is easy to understand the nature of the change, \nby referring to the facts mentioned in the third Lecture ; \nand the production of carbonic acid renders probable \nthe idea, that the principal chemical difference between \nsugar and mucilage depends upon a slight difference in \nthe proportions of their carbon. \n\nThe absorption of oxygene by the seed in germina- \ntion, has been compared to its absorption in producing \nthe evolution of foetal life in the egg : but this analogy \nis only remote. All animals, from the most to the least \nperfect classes, require a supply of oxygene.* From \n\n* The impregnated egs^s of insects, and even fishes, do not pro- \nduce younpj ones, unless they are supplied with air, that is, unless \nthe foetus can respire. I have found that the eggs of moihs did not \nproduce larva: when confined in pure carbonic acid ; and when they \nwere exposed in common air, the oxygene partly disappeared, and \ncarbonic acid was formed. The fish in the egg or spawn, gains its \noxygene from the air dissolved in water; and those fishes that spawn \nin spring and summer in still water, such as the pike, carp, perch, \nand bream, deposit their eggs upon subaquatic vegetables, the leaves \nof which, in performing their healthy functions, supply oxygene to \nthe water. Tlie fish that spawn in winter, such as the salmon and \ntrout, seek spots where there is a constant supply of fresh water, as \nnear the sources of streams as possible, and in the most ra])id cur- \nrents, where all stagnation is prevented, and where the water is satu- \nrated vvitii air, to which it has been exposed during its deposition \nfrom clouds. It is the instinct leading these fish to seek a supply of \n\n\n\np. 148 \n\n\n\n\n149 \n\nllie moment the heart begins to pulsate till it ceases to \nbeat, the aeration of the blood is constant, and the func- \ntion of respiration invariable ; carbonic acid is given off \nin the process, but the chemical change produced in the \nblood is unknown ; nor is the reany reason to suppose \nthe formation of any substance similar to sugar. In the , \nproduction of a plant from a seed, some reservoir of \nnourishment is needed before the root can supply sap : \nand this reservoir is the cotyledon in which it is stored \nup in an insoluble form, and protected if necessary du- \nring the winter, and rendered soluble by agents which \nare constantly present on the surface. The change of \nstarch into sugar, connected with the absorption of oxy- \ngene, may be rather compared to a process of fermenta- \ntion than to that of respiration ; it is a change effected \nupon unorganized matter, and can be artificially imita- \nted ; and in most of the chemical changes that occur \nwhen vegetable compounds are exposed to air, oxygene \nis absorbed, and carbonic acid formed or evolved. \n\nIt is evident, that in all cases of tillage the seeds should \nbe sown so as to be fully exposed to the influence of the \nair. And one cause of the unproductiveness of cold \nclayey adhesive soils is, that the seed is coated with \nmatter impermeable to air. \n\nIn sandy soils the earth is always sufficiently pene- \ntrable by the atmosphere ; but in clayey soils there can \nscarcely be too great a mechanical division of parts in \nthe process of tillage. Any seed not fully supplied with \nair, always produces a weak and diseased plant. \n\nThe process of malting which has been already refer- \nred to, is merely a process in which germination is ar- \ntificially produced; and in which the starch of the coty- \nledon is changed into sugar; which sugar is afterwards, \nby fermentation, converted into spirit. \n\nIt is very evident from the chemical principles of ger- \nmination, that the process of malting should be carried \non no farther than to produce the sprouting of the radi- \ncle, and should be checked as soon as this has made its \ndistinct appearance. If it is pushed to such a degree as \n\nair for their eggs which carries them from seas, or hikes into the \nniountuin country ; which induces them to move against ilie streauj, \nand to endeavour to overleap weirs, mill-dams, and calarat (s. \n\n\n\n15.0 \n\nto occasion the perfect developenient of the radicle and \nthe plume, a considerable quantity of saccharine matter \nwill have been consumed in producing their expansion, \nand there will be less spirit formed in fermentation, or \nproduced in distillation. \n\nAs this circumstance is of some importance, I made \nin October 1806, an experiment relating to it. I ascer- \ntained by the action of alcohol, the relative proportions \nof saccharine matter in two equal quantities of the same \nbarley ; in one of which the germination had proceeded \nso far as to occasion protrusion of the radicle to nearly \na quarter of an inch beyond the grain in most of the \nspecimens, and in the other of which it had been check- \ned before the radicle was a line in length ; the quantity \nof sugar afforded by the last was to that in the first near- \nly as six to five. \n\nThe saccharine matter in the cotyledons at the time \nof their change into seed-leaves, renders them exceed- \ningly liable to the attacks of insects : this principle is at \nonce a nourishment of plants and animals, and the great- \nest ravages are committed upon crops in this first stage \nof their growth. \n\nThe turnip fly, an insect of the colyoptera gfiinus, fixes \nitself upon the seed-leaves of the turnip at the time that \nthey are beginning to perform their functions : and when \nthe rough leaves of the plume are thrown forth, it is in- \ncapable of injuring the plant to any extent. \n\nSeveral methods have been proposed for destroying \nthe turnip fly, or for preventing it from injuring th6 crop. \nIt has been proposed to sow radish-seed with the tur- \nnip-seed, on the idea that the insect is fonder of the \nseed leaves of the radish than those of the turnip ; it is \nsaid that this plan has not been successful, and that the \nfly feeds indiscriminately on both. \n\nThere are several chemical menstrua which render the \nprocess of germination much more rapid, when the seeds \nhave been steeped in them. As in these cases the seed- \nleaves are quickly produced, and more speedily perform \ntheir functions, I proposed it as a subject of experiment \nto examine whether such menstrua might not be useful \nin raising the turnip more speedily to that state in \nwhich it would be secure from the fly ; but the result \n\n\n\n151 \n\nproved tliat the practice was inadmissible; for seeds so \ntreated, though they germinated much quicker, did not \nproduce healthy plants, and often died soon after sprout- \ning. \n\nI steeped radish seeds in September 1807, for twelve \nhours, in a solution of chlorine, and similar seeds in ve- \nry diluted nitric acid, in very diluted sulphuric acid, in \nweak solution of oxysulphate of iron, and some in com- \nmon water. The seeds in solutions of chlorine and \noxysulphate of iron, threw out the germ in two days ; \nthose in nitric acid in three days, in sulphuric acid in \nfive, and those in water in seven days. But in the \ncases of premature germination, though the plume was \nvery vigorous for a short time, yet it became at the end \nof a fortnight weak and sickly ; and at that period less \nvigorous in its growth than the sprouts which had been \nnaturally developed, so that there can be scarcely any \nuseful application of these experiments. Too rapid \ngrowth and premature decay seem invariably connected \nin organized structures ; and it is only by following the \nslow operations of natural causes, that we are capable \nof making improvements. \n\nThere is a number ef chemical substances which are \nvery oflFensive and even deadly to insects, which do not \ninjure, and some of which even assist vegetation. Se- \nveral of these mixtures have been tried with various suc- \ncess ; a mixture of sulphur and lime, which is very de- \nstructive to slugs, does not prevent the ravages of the \nfly on the young turnip crop. His Grace the Duke of \nBedford, at my suggestion, was so good as to order the \nexperiment to be tried on a considerable scale at Wo- \nburn farm : the mixture of lime and sulphur was strew- \ned over one part of the field sown with turnips ; nothing \nwas applied to the otlrer part, but both were attacked \nnearly in the same manner by the fly. \n\nMixtures of soot and quicklime, and urine and quick- \nlime, will probably be more efficacious. The volatile \nalkali given off by these mixtures is offensive to insects ; \nand they aftbrd nourishment to the plant. Mr. T. A. \nKnight* informs me, that he has tried the method by \n\n* IMr. Knight has been so good as to famish me with tl>e fol!o%v-- \ning note on this subject. \n\n\n\n152 \n\nammoniacal fumes with success ; but more extensive iiials \nare necessary to establish its general efficacy. It may, \nhowever, be safely adopted, for if it should fail in de- \nstroying the fly, it would at least be a useful manure to \nthe land. \n\nAfter the roots and leaves of the infant plant are form- \ned, the cells and tubes throughout its structure become \nfilled with fluid, which is usually supplied from the soil, \nand the function of nourishment is performed by the ac- \ntion of its organs upon the external elements. The con- \nstituent parts of the air are subservient to this process ; \nbut, as it might be expected, they act differently under \ndifferent circumstances. \n\nWhen a growing plant, the roots of which are sup- \n\n" The experiment which I tried the year before last, and last year, \nto preserve turnips from the fly, has not been sufficiently often re- \npeated to enable me to speak with any degree of decision ; and last \nyear all my turnips succeeded perfectly well. In consequence of \nyour suggestion, when I had the pleasure to meet you some years \nago at Holkham, that lime slacked with urine might possibly be \nfound to kill, or drive off, the insects from a turnip crop, I tried that \npreparation in mixture with three parts of soot, which was put into \na small barrel, with gimblet holes round it, to permit a certain quan- \ntity of the composition, about four bushels to an acre, to pass out, \nand to fall into the drills with the turnip seeds. Whether it was by \naffording highly stimulating food to the plant, or giving some flavour \nwhich the flies did not like, I cannot tell ; but in the year 1811, the \nadjoining rows were eaten away, and those to which the composition \nwas applied, as above described, were scarcely at all touched. It is \nmy intention in future to drill my crop in, first, with the composition \non the top of the ridge ; and then to sow at least a pound of seed, \nbroad-cast over the whole ground. The expense of this will be ve- \nry trifling, not more than 2s. per acre ; and the horse-hoe will instant- \nly sweep away all the supernumeraries between the rows, should \nthose escape the flies, to which however they will be chiefly attract- \ned; because it will always be found that these insects prefer turnips \ngixjwing in poor, to those in rich ground. One advantage seems to \nbe the acceleration given to the growth of the plants, by the highly \nstimulative effects of the food they instantly receive as soon as their \ngrowth commences, and long before their radicles have reached the \ndung. The directions above given apply only to turnips sowed \\ipon \nridges, with the manure immediately under them ; and I am quite \ncertain, that in all soils turnips should be thus cultivated. The close \nvicinity of the manure, and the consequent short time required to \ncarry the food into the leaf, and return the organizable matter to the \nroots, arc, in my hypothesis, points of vast importance ; and the re- \nsults in practice are correspondent." \n\n\n\n153 \n\nplied with a proper nourishment, is exposed in the pre- \nsence of solar light to a given quantity of atmospherical \nair, containing its due proportion of carbonic acid, the \ncarbonic acid after a certain time is destroyed, and a \ncertain quantity of oxygene is found in its place. If \nnew quantities of carbonic acid gas be supplied, the \nsame result occurs ; so that carbon is added to plants \nfrom the air by the process of vegetation in sunshine ; \nand oxygene is added to the atmosphere. \n\nThis circumstance is proved by a number of experi- \nments made by Drs. Priestly, Ingenhouz and Wood- \nhouse, and M- T. de Saussure ; many of which I have re- \npeated with similar results. The absorption of carbonic \nacid gas, and the production of oxygene are performed \nby the leaf; and leaves recently separated from the tree \neffect the change, when confined in portions of air con- \ntaining carbonic acid; and absorb carbonic acid and \nproduce oxygene, even wlien immersed in water hold- \ning carbonic acid in solution. \n\nThe carbonic acid is probably absorbed by the fluids \nin the cells of the green or parenchymatous part of the \nleaf; and it is from this part that oxygene gas is produ- \nced during the presence of light. M. Sennebier found \nthat the leaf, from which the epidermis was stripped off, \ncontinued to produce oxygene when placed in water, \ncontaining carbonic acid gas, and the globules of air \nrose from the denuded parenchyma ; and it is shewn \nboth from the experiments of Sennebier and Wood- \nhouse, that the leaves most abundant in parenchymatous \nparts produce most oxygene in water impregnated with \ncarbonic acid. \n\nSome few plants* will vegetate in an artificial atmo- \nsphere, consisting principally of carbonic acid, and ma- \nny will grow for some time in air, containing from one- \nhalf to one- third ; but they are not so healthy as when \nsupplied with smaller quantities of this elastic sub- \nstance. \n\nPlants exposed to light have been found to produce \noxygene gas in an elastic medium and in water, con- \n\n* I found the Arenaria tenuifolia to produce oxygene in carbonic \nacid, which was nearly pure. \n\n\n\n154 \n\ntahiiiie; no carbonic^ acid gas ; but in quantities much \nsmaller tlian when carbonic acid gas was present. \n\nIn the dark no oxygene gas is produced by plants, \nwhatever be tlie elastic medium to which they are expo- \nsed ; and no carbonic acid absorbed. In most cases, on \nthe contrary, oxygene gas, if it be present, is absorbed, \nand carbonic acid gas is produced. \n\nIn the changes that take place in the composition of \nthe organized parts, it is probable that saccharine com- \npounds are principally formed during the absence of \nlight; gum, Voody fibre, oils, and resins during its pre- \nsence ; and the evolution of carbonic acid gas, or its \nformation during the night, may be necessary to give \ngreater solubility to certain compounds in the plant. I \nonce suspected that all the carbonic acid gas produced \nby plants in the night, or in shade, might be owing to \nthe decay of some part of the leaf, or epidermis; but the \nrecent experiments of Mr. D. Ellis are opposed to this \nidea; and I found that a perfectly healthy plant of cele- \nry, placed in a given portion of air for a few hours on- \nly, occasioned a production of carbonic acid gas, and an \nabsorption of oxygene. \n\nSome persons have supposed that plants exposed in \nthe free atmosphere to the vicissitudes of sunshine and \nshade, light and darkness, consume more oxygene than \nthey produce, and that their permanent agency upon air \nis similar to that of animals ; and this opinion is espou- \nsed by the writer on the subject 1 have just quoted, in \nhis ingenious researches on vegetation. But all expe- \nriments brought forwards in favour of this idea, and \nparticularly his experiments, have been made under cir- \ncumstances unfavourable to accuracy of result. The \nplants have been confined and supplied with food in an \nunnatural manner; and the influence of light upon them \nhas been very much diminished by the nature of the me- \ndia through which it passed. Plants confined in limit- \ned portions of atmospheric air soon become diseased ; \ntheir leaves decay, and by their decomposition they ra- \npidly destroy the oxygene of the air. In some of the \nearly experiments of Dr. Priestly before he was ac- \nquainted with the agency of light upon leaves, air that \njiad supported combustion and respiration, was found \n\n\n\n155 \n\npurified by the growth of plants when they were expo- \nsed in it for successive days and nights ; and his expe- \nriments are the more unexceptionable, as the plants, in \nmany of them, grew in their natural states ; and shoots, \nor branches from them, only were introduced through \nwater in the confined atmosphere. \n\n1 have made some few researches on this subject, and \nI shall describe their results. On the 12th of July, 1800, \nI placed a turf four inches square, clothed with grass, \nprincipally meadow fox- tail, and white clover, in a \nporcelain dish, standing in a shallow tray filled with \nwater ; 1 then covered it with a jar of flint glass, con- \ntaining 380 cubical inches of common air in its natural \nstate. It was exposed in a garden, so as to be liable to \nthe same changes with respect to light as in the common \nair. On the 20th of July the results were examined. \nThere was an increase of the voKime of the gas, amount- \ning to fifteen cubical inches ; but the temperature had \nchanged from 64\xc2\xb0 to Tl\'\' ; and the pressure of the at- \nmosphere, w^hich on the 12th had been equal to the sup- \nport of 30.1 inches of mercury, was now equal to that \nof 30.2. Some of the leaves of the white clover, and \nof the fox-tail were yellow, and the whole appearance \nof the grass less healthy than when it was first introdu- \nced. A cubical inch of the gas, agitated in lime-wa- \nter, gave a slight turbidness to the Avater ; and the ab- \nsorption was not quite one-one hundred and fiftieth of \nits volume. 100 parts of the residual gas exposed to a \nsolution of green sulphate of iron, impregnated with ni- \ntrous gas, a substance which rapidly absorbs oxygene \nfrom air, occasioned a diminution to 80 parts. 100 parts \nof the air of the garden occasioned a diminution to 79 \nparts. \n\nIf the results of this experiment be calculated upon \nit, it will appear that the air had been slightly deterio- \nrated by the action of the grasses. But the weather was \nunusually cloudy during the progress of the experiment; \nthe plants had not been supplied in a natural manner \nwith carbonic acid gas; and the quantity formed during \nthe night, and by the action of the faded leaves, must \nhave been partly dissolved by the water ; and that this \n"was actually the case, I proved by pouring lime-water \n\n\n\n156 \n\ninto the wattr, when an immediate precipitation was oc- \ncasioned. The increase of azote 1 am inclined to attri- \nbnte to common air disengaged from the water. \n\nThe following experiment I consider as conducted \nunder circumstances more analogous to those existing in \nnature. A turf four inches square, from an irrigated \nmeadow, clothed with common meadow grass, meadow \nfox-tail grass, and vernal meadow grass, was placed in \na porcelain dish, which swam on the surface of water \nimpregnated with carbonic acid gas. A vessel of thin \nflint glass, of the capacity of 230 cubical inches, having \na funnel furnished with a stop-cock inserted in the top, \nwas made to cover the grass ; and the apparatus was ex- \nposed in an open place; a small quantity of water was \ndaily supplied to the grass by means of the stop-cock.* \nEvery day likewise a certain quantity of water was re- \nmoved by a si[)lion, and water saturated with carbonic \nacid gas supplied in its place ; so that it may be presu- \nmed, that a small quantity of carbonic acid gas was con- \nstantly present in the receiver. On the 7th of July, \n1807, the first day of the experiment, the weather was \ncloudy in the morning, but fine in the afternoon ; the ther- \nmometer at 67, the barometer 30.2 : towards the evening \nof this day a slight increase of the gas was perceived, \nthe next three days were bright; but in the morning of \nthe 11th the sky was clouded; a considerable increase \nof the volume of the gas was now observed : the 12th \nwas cloudy, with gleams of sunshine ; there was still \nan increase, but less than in the bright days ; the 13th \nwas bright. About nine o\'clock A. M. on the 14th the \nreceiver was quite full ; and considering the original \nquantity in the jar, it must have been increased by at \nleast 30 cubical inches of elastic fluid : at times during \nthis day globules of gas escaped. At ten on the morn- \ning of the 15th, 1 examined a portion of the gas; it con- \ntained less than one-fiftieth of carbonic acid gas : 100 \nparts of it exposed to the impregnated solution left only \n75 parts ; so that the air was four per cent, purer than \nthe air of the atmosphere. \n\nI shall detail another similar experiment made with \n\n* See Fig. \\7, \n\n\n\n157 \n\nequally decisive results. A shoot from a vine, having \nthree healthy leaves belonging to it, attached to its pa- \nrent tree, was bent so as to be placed under the receiver \nwhich bad been used in the last experiment ; the water \nconfining the common air was kept in the same manner \nimpregnated with carbonic acid gas ; the experiment was \ncarried on from August 6th, till August 14th, 1807 ; \nduring this time, though the weather had been general- \nly clouded, and there had been some rain, the volume \nof elastic fluid continued to increase. Its quality was \nexamined on the morning of the 15tii ; it contained one- \nforty- second of carbonic acid gas, and 100 parts of it \nafforded 23.5 of oxygene gas. \n\nThese facts confirm the popular opinion, that when \nthe leaves of vegetables perform their healthy functions, \nthey tend to purify the atmosphere in the common va- \nriations of weather, and changes from light to dark- \nness. \n\nIn germination, and at the time of the decay of the \nleaf, oxygene must be absorbed ; but when it is consi- \ndered how large a part of the surface of the earth is cloth- \ned with perennial grasses, and that half of the globe is \nalways exposed to the solar light, it appears by far the \nmost probable opinion, that more oxygene is produced \nthan consumed during the process of vegetation; and that it \nis this circumstance which is the principal cause of the \nuniformity of the constitution of the atmosphere. \n\nAnimals produce no oxygene gas during the exercise \nof any of their functions and they are constantly con- \nsuming it; but the extent of the animal, compared to \nthat of the vegetable kingdom, is very small ; and the \nquantity of carbonic acid gas produced in respiration, \nand in various processes of combustion and fermenta- \ntion, bears a proportion extremely minute to the whole \nvolume of the atmosphere : if every plant during the \nprogress of its life makes a very small addition of oxy- \ngene to the air, and occasions a very small consumption \nof carbonic acid, the effect may be conceived adequate \nto the wants of nature. \n\nIt may occur as an objection to these views, that if the \nleaves of plants purify the atmosphere, towards the, end \nof autumn, and through the winter, and early spring, \n\n\n\n158 \n\ntlie air in our climates must become impure, the oxygeiie \niu it diminish, and the carbonic acid ij;as increase, which \nis not the case ; but there is a very satisfactory answer \nto tliis objection. The different parts of the atmosphere \nare constantly mixed toi;ether by winds, which when \nthey are strong, move at the rate of from 60 to 100 miles \nin an hour. In our winter, the south-west gales convey \nair, which has been purified by the vast forests and sa- \nvannas of Houth America, and which, passing over the \nocean, arrives in an uncontaminated state. The storms \nand tempests which often occur at the beginning, and \ntowards the middle of our winter, and which generally \nblow from the same quarter of the globe, have a salu- \ntary influence. 15y constant agitation and motion, the \nequilibrium of the constituent parts of the atmosphere \nis preserved; it is fitted for the purposes of life ; and \nthose events, which the superstitious formerly referred \nto the w rath of heaven, or the agency of evil spirits, \nand in w hich they saw only disorder and confusion, are \ndemonstrated by science, to be ministrations of divine \nintelligence, and connected with the order and harmony \nof our system. \n\nI have reasoned, in a former part of this Lecture, \nagainst the close analogy which some persons have as- \nsumed between the absorption of oxygeue and the for- \nmation of carbonic acid gas in germination, and in the \nrespiration of the fix\'tus. Similar arguments will apply \nagainst the pursuit of this analogy, between the functions \nof the leaves of the adult plant, and those of the lungs \nof the adult animal. Plants grow vigorously only when \nsupplied Avith light ; and most species die if deprived \nof it. It cannot be supposed that the production of \noxygene from the leaf, which is known to be connected \nwith its natural colour, is the exertion of a diseased \nfunction, or that it can acquire carbon in the day-time, \nwhen it is in most vigorous growth, when the sap is ri- \nsing, when all its powers of obtaining nourishment are \nexerted ; merely for the purpose of giving it off again \nin the night, when its leaves are closed, when the motion \nof the sap is imperfect, and when it is in a state ap- \nproaching to that of (piiescence. Many plants that grow \nupon rocks, or soils, containing no carbonic matter, can \n\n\n\n151^ \n\nf)iity be supposed to acquire their charcoal from the \ncarbonic acid gas in the atmosphere ; and the leaf may \nbe considered at the same time as an organ of absorption, \nand an organ in which the sap may undergo different \nchemical changes. \n\nWhen pure water only is absorbed ])y tlie roots of \nplants, the fluid, in passing into tiie leaves, will proba- \nbly have greater power to absorb carbonic acid from the \natmosphere. When the water is saturated with carbon- \nic acid gas, some of this substance, even in the sunshine, \nmay be given off by the leaves ; but a part of it like- \nwise will be always decomposed, which has been pro- \nved by the experiments of M. Sennebier. \n\nWhen the fluid taken up by the roots of plants con- \ntains much carbonaceous matter, it is probable that plants \nmay give off carbonic acid from their leaves, even in \nthe sunshine. In short, the function of the leaf must \nvary according to the composition of the sap passing \nthrough it ; and according to the nature of the products \nwhich are formed from it. Wlien sugar is to be pro- \nduced, as in early spring at the time of the development \nof buds and flowers, it is probable that less oxygene will \nbe given off, than at the time of the ripening of the seed, \nwhen starch, or gums, or oils, are formed; and the pro- \ncess of ripening the seed usually takes place when the \nagency of the solar light is most intense. When the \nacid juices of fruits become saccharine in the natural \nprocess of vegetation, more oxygene, there is every rea- \nson to believe, must be given off, or newly combined, \nthan at other times ; for, as it was shewn in the Third \nLecture, all the vegetable acids contain more oxygene \nthan sugar. It appears probable, that in some cases, in \nwhich oily and resinous bodies are formed in vegetation, \nwater may be decomposed; its oxygene set free, and its \nhydrogene absorbed. \n\nI have already mentioned, that some plants produce \noxygene in pure water; Dr. Ingenhouz found this to be \nthe case with species of the confervse, I have tried \nthe leaves of many plants, particularly those tiiat pro- \nduce volatile oils. When such leaves are exposed in \nwater saturated with oxygene gas, oxygene is given off* \nin the solar light ; but the quantity is very small and al- \n\n\n\n160 \n\nMays limited ; nor have I been able to ascertain with \ncertainty, whether Uie vegetative powers of the leaf were \nconcerned in tlie operation, though is seems probable. \nI obtained a considerable quantity of oxygene in an ex- \nperiment made fifteen years ago, in which vine leaves \nwere exposed to pure water ; but on repeating tlie trial \noften since, the quantities have always been very much \nsmaller ; I am ignorant whether this difference is owing \nto the peculiar state of the leaves, or to some confervae \nwhich might have adhered to the vessel, or to other \nsources of fallacy. \n\nThe most important and most common products of ve- \ngetables, mucilage, starch, sugar, and woody fibre, are \ncomposed of water, or the elements of water, in their \ndue proportion, and charcoal; and these, or some of \nthem, exist in all plants ; and the decomposition of car- \nbonic acid, and the combination of water in vegetable \nstructures, are processes which must occur almost uni- \nversally. \n\nWhen glutenous and albuminous substances exist in \nplants,* the azote they contain may be suspected to be \nderived from the atmosphere : but no experiments have \nbeen made which prove this ; they might easily be in- \nstituted upon mushrooms and funguses. \n\nIn cases in which buds are formed, or shoots thrown \nforth from roots, oxygene appears to be uniformly ab- \nsorbed, as in the germination of seeds. I exposed a \nsmall potato moistened with common water to 24 cubi- \ncal inches of atmospherical air, at a temperature of 59^. \nIt began to throw forth a shoot on the third day ; when \nit was a half au inch long I examined the air ; nearly \na cubical inch of oxygene was absorbed, and about tliree- \nfourths of a cubical inch of carbonic acid formed. The \njuices in the shoot separated from the potato, had a \nsweet taste ; and the absorption of oxygene, and the \nproduction of carbonic acid, were probably connected \nwith the conversion of a portion of starch into sugar. \nWhen potatoes that have been frozen are thawed, they \nbecome sweet ; probably oxygene is absorbed in this \nprocess ; if so, the change may be prevented by thaw- \ning them out of the contact of air ; under water, for in- \nstance, that has been recently boiled. \n\n\n\n161 \n\nIn the tillering of corn, that is, the production of new \nstalks round the original plume, there is every reason \nto believe that oxygene must be absorbed ; for the stalk \nat which the tillering takes place, always contains sugar, \nand the shoots arise from a part deprived of light. The \ndrill husbandry favours this process ; for loose earth is \nthrown by hoeing round the stalks ; they are preserved \nfrom light, and yet supplied with oxygene. I have \ncounted from forty to one hundred and twenty stalks \nproduced from a grain of wheat, in a moderately good \ncrop of drilled wheat. And we are informed by Sir \nKenelm Digby, in 1660, that there was in the posses- \nsion of the Fathers of the Christian Doctrine at Paris, \na plant of barley, which they, at that time, kept l)y them \nas a curiosity, and which consisted of 249 stalks spring- \ning from one root, or grain ; and in which they counted \nabove 18,000 grains, or seeds of barley. \n\nThe great increase which takes place in the transplan- \ntation of wheat, depends upon the circumstance, tjiat each \nlayer thrown out in tillering may be removed, and treat- \ned as a distinct plant. In the Philosophical Transac- \ntions, Vol. Lviii. p. 203, the following statement may \nbe found : Mr. C. Miller, of Cambridge, sowed some \nwheat on the 2d of June, 1766 ; and on the 8th of \nAugust, a plant was taken and separated into 18 partS;, \nand replanted ; these plants were again taken up, and \ndivided in the months of September and October, and \nplanted separately to stand the winter, which division \nproduced 67 plants. They were again taken up in \nMarch and April, and produced 500 plants : the num- \nber of ears thus formed from one grain of wheat was \n21,109, which gave three pecks and three quarters of \ncorn that weighed 471bs. 7ozs. ; and that were estima- \nted at 576,840 grains. \n\nIt is evident from the statements just given, that the \nchange which takes place in the juices of the leaf by \nthe action of the solar light, must tend to increase the \nproportion of inflammable matter to their other consti- \ntuent parts. And the leaves of the plants that grow in \ndarkness, or in shady places, are uniformly pale ; their \njuices are watery and saccharine, and they do not afford \n\nX \n\n\n\n162 \n\noils or icsiuous substances. 1 shall detail an exp6ri- \nment on this suhject. \n\nI took an equal weight, 400 grains, of the leaves of \ntwo plants of endive, one bright green, which had grown \nfully exposed to light, and the otiier almost white, which \nhad been secluded from light by being covered with a \nbox ; after being both acted upon for some time by boil- \ning water, in the state of pulp, the undissolved matter \nwas dried, and exposed to the action of warm alcohol. \nThe matter from the green leaves gave it a tinge of olive; \nthat from the pale leaves did not alter its colour. Scarcely \nany s(did matter was produced by evaporation of the \nalcohol tliat had been digested on the pale leaves : where- \nas by the evaporation of that from the green leaves, a \nconsiderable residuum was obtained : five grains of which \nwere separated from the vessel in which the evaporation \nwas carried on ; they burnt with flame, and appeared \npartly matter analogous to resin. 53 grains of woody \nfibre were obtained from the green leaves, and only 31 \nfrom the pale leaves. \n\nIt has been mentioned in the Third Lecture, that the \nsap probably, in common cases, descends from the leaves \ninto the bark; the bark is usually so loose in its texture, \nthat the atmosphere may possibly act upon it in the cor- \ntical layers ; but the changes taking place in the leaves, \nappear sufficient to ex[dain the diflerence between the \nproducts obtained from the bark and from the alburnum ; \nthe first of which contains more carbonaceous matter \nthan the last. \n\nWhen the similarity of the elements of diflferent ve- \ngetable products is considered, according to the views \ngiven in the Third Lecture, it is easy to conceive how \nthe different organized parts may be formed from the \nsame sap, according to the manner in which it is acted \non by heat, light and air. By the abstraction of oxy- \ngene, the different inflammable products, fixed and vola- \ntile oils, resins, camphor, woody fibre, &c. may be pro- \nduced from saccharine or mucilaginous fluids ; and by \nthe abstraction of carbon and iiydrogene, starch, sugar, \nthe diflerent vegetable acids and substances soluble in \nwater, may be formed from highly corabu\xc2\xabtible and in- \n\n\n\ni6^ \n\nsolu?)le substances. Even the limpid volatile oils which \nconvey the fragrance of the flower, consist of different \nproportions of the same essential elements, as the dense \nwoody fibre ; and both are formed by different changes \nin the same organs, from the same materials, and at the \nsame time. \n\nM. Vauquelin has lately attempted to estimate the \nchemical changes taking place in vegetation, by analy- \nsing some of the organized parts of the horse-chesnut \nin their different stages of growth. He found in ti\xc2\xbbe \nbuds collected, March 7, 18d2, tanning principle, and \nalbuminous matter capable of being obtained separately, \nbut when obtained, comliining with each other. In the \nscales surrounding the buds, he found the tanning prin- \nciple, a little saccharine matter, resin and a fixed oil. In \nthe leaves fully developed, he discovered the same prin- \nciples as in the buds ; and in addition, a peculiar green \nresinous matter. The petals of the flower yielded a \nyellowish resin, saccharine matter, albuminous matter, \nand a little wax : the stamina afforded sugar, resin, and \ntannin. \n\nThe young chesnuts examined immediately after their \nformation, afforded a larger quantity of a matter which \nappeared to be a combination of albuminous matter and \ntannin. All the parts of the plant afforded saline com- \nbinations of the acetic and phosphoric acids. \n\nM. Vauquelin could not obtain a sufficient quantity \nof the sap of the horse-chesnut for examination ; a cir- \ncumstance much to be regretted ; and he has not stated \nthe relative quantities of the different substances in the \nbuds, leaves, flowers, and seeds. It is probable, how- \never, from his unfinished details, that the quantity of \nresinous matter is increased in the leaf, and that the \nwhite fibrous pulp of the chesnut is formed by the mu- \ntual action of albuminous and astringent matter, which \nprobably are supplied by different cells or vessels. I \nhave already mentioned* that the cambium, from which \nthe new parts in the trunk and branches appear to be \nformed, probably owes its powers of consolidation to \nthe mixture of two different kinds of sap ; one of which \n\n*P. 104. \n\n\n\nJ (i4 \n\nflo^vs upwards from the roots; and other ol\' which pro- \nbably descends from the leaves. 1 attenipledj in May \n1804, at the time the cambium was forming in tlie oak, \nto ascertain the nature of the action of the sap of the \nalburnum upon the juices of the bark. By perforatine; \nthe alburnum in a youni^oak, and applying an exhaust- \ning syringe to the aperture, 1 easily drew out a small \nquantity of sap. 1 could not, however, in the same way \nobtain sap from tlie bark. 1 was obliged to recur to the \nsoluti\xc2\xab)n of its principles in water, by infusing a small \nquantity of fresli bark in warm water; the liquid obtain- \ned in this way was highly coloured and astringent ; and \nproduced an immediate precipitate in the alburnous sap, \nthe taste of wliich was sweetish, and slightly astringent, \nand which was colourless. \n\nTlie in(;reasc of trees and plants must depend upon \nthe quantity of sap which passes into their organs ; upon \nthe quality of this sap; and on this modification by the \nprinciples of the atmosphere. Water, as it is the vehi- \ncle of the nourishment of the plant, is the substance \nprincipally given off by the leaves. Dr. Hales found, \nthat a sunflower, in one day of twelve liours, transpired \nhy its leaves one pound fourteen ounces of water, all of \nAvhich must have been imbi])ed by its roots. \n\nThe powers which cause the ascent of tlie sap have \nheen slightly touched upon in the Second and Third \nLectures. The roots imbibe fluids from the soil by ca- \npillary attraction ; but this power aU)ne is insufficient to \naccount for the rapid elevation of the sap into the leaves. \nThis is fully proved by the following fact detailed by \nDr. Hales, Vol. 1. of the Vegetable Statics, page 114. \nA vine branch of four or five years old was cut through, \nand a glass tube carefully attached to it; this tube was \nbent as a siphon, and filled with quicksilver; so that the \nforce of the ascending sap could be measured by its ef- \nfect in elevating the quicksilver. In a few days it was \nfound, that the sap had been propelled forwards with \nso much force, as to raise the quicksilver to 38 inches, \nwhich Is a force considerably superior to that of the usual \npressure of the atmosphere. Capillary attraction can \nonly be exerted by the surfaces of small vessels, and \ncan never raise a iluid into tubes above the vessels tliem- \nselvc.?\xc2\xbb. \n\n\n\n.165 \n\n1 Fefeired in the liegiuiiing of the Third Lecture to \nMr. Knight\'s opinion, that the contractions and expan- \nsions of the silver grain in the alburnum, are the most \nefficient cause of the ascent of the fluids contained in \nits pores and vessels. The views of this excellent ])hy- \nsiologist are rendered extremely probable by the facts \nbe has brought forward in support of them. Mr. Knight \nfound that a very small increase of temperature was suf- \nficient to cause the fibres of the silver grain to separate \nfrom each other, and that a very slight diminution of \nheat produced their contraction. The sap rises most \nvigorously in spring and autumn, at the time the tempe- \nrature is variable; and if it be supposed, that in expand- \ning and contracting, the elastic fibres of the silver grain \nexercise a pressure upon the cells and tubes containing \nthe fluid absorbed by tlie capillary attraction of tlie roots, \nthis fluid must constantly move upwards towards the \npoints where a supply is needed. \n\nThe experiments of Montgolfier, the celebrated in- \nventor of the balloon, have shewn that water may be \nraised almost to an indefinite height by a very small \nforce, provided its pressure be taken off by continued \ndivisions in the column of fluid. This principle, there \nis great reason to suppose, must operate in assisting the \nascent of the sap in the cells and vessels of plants which \nhave no rectilineal communication, and which every \nwhere oppose obstacles to the perpendicular pressure of \nthe sap. \n\nThe changes taking place in the leaves and buds, and \nthe degree of their power of transpiration, must be in- \ntimately connected likewise with the motion of the sap \nupwards. This is shewn by several experiments of Dr. \nHales. \n\nA branch from an apple tree was separated and in- \ntroduced into water, and connected with a mercurial \ngage. When the leaves were upon it, it raised the mer- \ncury by the force of the ascending juices to four inches ; \nbut a similar branch, from which the leaves were remo- \nved, scarcely raised it a quarter of an inch. \n\nTliose trees, likewise, whose leaves arc soft and of a \nspongy texture, and porous at their upper surfaces, dis- \nplayed by far the greatest powers with regard to the ele- \nvation of the sap. \n\n\n\n166 \n\nThe same accurate philosopher whom 1 have just \nquoted, found that the pear, quince, cherry, walnut, \npeach, gooseberry, water- elder_, and sycamore, which \nhave all soft and unvarnished leaves, raised the mercu- \nry under favourable circumstances from three to six \ninches. Whereas the elm, oak, chesnut, hazel, sallow, \nand ash, which have firmer and more glossy leaves, \nraised the mercury only from one to two inches. And \nthe evergreens and trees bearing varnished leaves, \nscarcely at all affected it ; particularly the laurel and the \nlauristinus. \n\nIt will be proper to mention the facts which shew, that \nin many cases fluids descend through the bark ; they are \nnot of the same unequivocal nature as those which de- \nmonstrate the ascent of the sap through the alburnum ; \nyet many of them are satisfactory. \n\nM. Baisse placed branches of different trees in an in- \nfusion of madder, and kept them there for a long time. \nHe found in all cases, that the wood became red before \ntlie bark ; and that the bark began to receive no tinge \ntill the whole of the wood was coloured, and till the \nleaves were affected ; and that the colouring matter first \nappeared above, in the bark immediately in contact with \nthe leaves. \n\nSimilar experiments were made by M. Bonnet, and \nwith analogous results, though not so perfectly distinct \nas those of M. Baisse. \n\nDu Hamel found, that in different species of the pine \nand other trees, when strips of bark were removed, the \nupper part of the wound only emitted fluid, whilst the \nlower part remained dry. \n\nThis may likewise be observed in the summer in fi\'uit- \ntrees, when the bark is wounded, the alburnum remain- \ning untouched. \n\nI have mentioned in the Third Lecture, that when \nnew bark is formed to supply the place of a ring that \nhas been stripped off, it first makes its appearance upon \nthe upper edge of the wound, and spreads slowly down- \nwards ; and no new matter appears from below rising up- \nwards, if the experiment has been carefully performed. \nI say carefully performed ; because, if any of the inte- \nrior cortical layer be suffered to remain communicating \n-with the upper edge^ new bark chvei\'ed \\yjth e"pidermis \n\n\n\n167 \n\n"Will form below this, and appear as if protruded upoii \nthe naked alburnum, and formed within the wound; and \nsuch a circumstance would give rise to erroneous con- \nclusions. \n\nIn the summer of 1804, 1 examined some elms at Ken- \nsington. The bark of many of them had been very much \ninjured, and, in some cases, more than a square foot \nhad been stripped oif. In most of the wounds the for- \nmation of the new cortical layers was from above, and \ngradually extending downwards round the aperture; \nbut in two instances there had been very distinctly a for- \nmation of bark towards the lower edge. 1 was, at first, \nvery much surprised at this appearance, so contradicto- \nry to the general opinion ; but, on passing the point of a \npen- knife along the surface of the alburnum, from below \nupwards, I found that a part of the cortical layer, which \nwas of the colour of the alburnum, had remained com-, \nmunicating with the upper edge of the wound, and that \nthe new bark had formed from this layer. I have had \nno opportunity of looking at the trees lately ; but I doubt \nnot that the phsenomenon may still be observed ; for some \nyears must elapse before the new formations will be \ncomplete. \n\nIn accounting for the experiment of M. Palisot de \nBeauvois, mentioned in the Third Lecture, it may be \nsupposed that the cortical fluid flowed down the albur- \nnum upon the insulated bark, and thus occasioned its \nincrease ; or it may be conceived that the bark itself \ncontained sufficient cortical fluid at the time of its sepa- \nration to form new parts by its action upon the alhur- \nnous fluid. \n\nThe motion of the sap through the bark seems prin- \ncipally to depend upon gravitation. When the watery \nparticles have been considerably dissipated by the tran- \nspiring functions of the leaves, and the mucilaginous, \ninflammable, and astringent constituents, increased by \nthe agency of heat, light, and air, the continued impulse \nupwards from the alburnum, forces the remaining in- \nspissated fluid into the cortical vessels, which receive \nno other supply. In these, from its weight, its natural \ntendency must be to descend ; and the rapidity of the \ndescent must depend u|>on the general consumption of \n\n\n\n4.68 \n\nthe fluids of the bark in the living processes of vegeta- \ntion ; for there is every reason to believe, that no fluid \npasses into the soil tlirough the roots ; and it is impos- \nsible to conceive a free lateral communication between \nthe absorbent vessels of the alburnum in the roots, and \nthe transporting or carrying vessels of the bark ; for if \nsuch a communication existed, there is no reason why \nthe sap should not rise through the bark as well as through \nthe alburnum ; for the same physical powers would then \noperate upon both. \n\nSome authors have supposed that the sap rises in the \nalburnum, and descends through the bark in consequence \nof a power similar to that which produces the circula- \ntion of the blood in animals ; a force analogous to the \nmuscular force in the sides of the vessels. \n\nDr. Thomson in his System of Chemistry, has stated \na fact which he considers as demonstrating the irratibi- \nlity of living vegetable systems. When a stork of spurge \n(Euphorbia peplis) is separated by two incisions from \nits leaves and roots, the milky fluid flows through both \nsections. Now, says the ingenious author, it is impos- \nsible that this could happen without the living action of \nthe vessels, for they cannot have been more than full ; \nand their diameter is so small, that if it were to conti- \nnue unaltered, the capillary attraction would be more \nthan sufficient to contain their contents, and, consequent- \nly, not a drop would flow out. Since, therefore, the li- \nquid escapes, it must be driven out by a force different \nfrom a common physical force. \n\nTo this reasoning it may be answered, that the sides \nof all the vessels are soft, and capable of collapsing by \ngravitation, as veins do in animal systems long after \nthey have lost all their vitality : which is an effect to- \ntally different from vital or irritable action ; and the \nphsenomenon may be compared to that of puncturing a \nvessel of elastic gum filled with fluid, both above an,d \nbelow ; the fluid will make its way tlirough the aper- \ntures, though in much larger quantity from the lowest, \nwhich I have found is likewise the case with the \nspurge. \n\nl)r. Jjarton has stated, that plants grow more vigor- \nmisly in water in which a little camphor has been infii- \n\n\n\n169 \n\nsed. This has been brought foivvard as a fact in favour \nof tlie iFritability of the vegetable tubular system. It \nis said, that camphor can only be conceived to act as a \nstimulus, by increasing the living powers of the vessels,, \nand causing them to contract with more energy. But \nthis kind of speculation is very unsatisfactory. Cam- \nphor, we know, has a disagreeable pungent taste, and \npowerful smell ; but physicians are far from being \nagreed whether it is a stimulant or sedative, even in \nits operation upon the human body. We should have \nno right whatever, even supposing the irritability of ve- \ngetables proved, to conclude, that because camphor as- \nsisted the growth of plants, it acted on their living pow- \ners ; and it is not right to infer the existence of a pro- \nperty proved in no other way, from the operation of un- \ncertain qualities. \n\nThat camphor may assist the growth of plants it is \neasy to conceive ; and why should Ave not consider its \nefficacy as similar to the efficacy of saccharine and mu- \ncilaginous matter, and particularly of oils, to which it is \nnearly allied in composition ; and which afford food to \nthe plant, and not stimulus ; which are materials of as- \nsimilation, and not of excitement ? \n\nThe arguments in favour of a contraction similar to \nmuscular action have not then much weight; and besides, \nthere are direct facts which render the opinion highly \nimprobable. \n\nWhen a single branch of a vine or other tree is intro- \nduced in winter into a hot-house, the trunk and the other \nbranches remaining exposed to the cold atmospliere, the \nsap will soon begin to move towards the buds in the \nheated branch ; these buds will gradually unfold them- \nselves, and begin to transpire ; and at length open into \nleaves. Now if any peculiar contractions of the sap ves- \nsels or cells were necessary for the ascent of the sap in \nthe vessels, it is not possible that the application of heat \nto a single branch should occasion irritable action to take \nplace in a trunk many feet removed from it, or in roots \nfixed in the cold soil : but allowing that the energy of \nlieat raises the fluid merely by diminishing its gravity, \nincreasing the facility of capillary action, and by produ- \ncing an expansion of the fibres of the silver grain, the \n\nY \n\n\n\n171) \n\nphaenomeuou is iu perfect unison witb tlie views advan- \nced in the preceding part of tliis Lecture. \n\nThe ilexj or evergreen oak, preserves its leaves through \nthe winter, even when grafted upon the common oak ; and \nin consequence of the operation of the leaves, there is a \ncertain motion of the sap towards the ilex, which, as \niu the last case, seems to be inconsistent with the theo- \nry of irritable action. \n\nIt is impossible to peruse any considerable part of the \nYegetable Statics of Hales, without receiving a deep \nimpression of the dependence of the motion of the sap \nupon common physical agencies. In the same tree this \nsagacious person observed, that in a cold cloudy morn- \ning when no sap ascended, a sudden change was pro- \nduced by a gleam of sunshine, of half an hour ; and a \nvigorous motion of the fluid. The alteration of the wind \nfrom south to the north immediately checked the effect. \nOn the coming on of a cold afternoon after a hot day, \nthe sap that had been rising began to fall. A warm \nshower and a sleet storm produced opposite effects. \n\nMany of his observations likewise shew, that the dif- \nferent powers which act on the adult tree, produce dif- \nferent effects at different seasons. \n\nThus, in the early spring, before the buds expand, \nthe variations of the temperature, and changes of the \nstate of the atmosphere with regard to moisture and dry- \nness, exert their great effects upon the expansions and \ncontractions of the vessels ; and then the tree is in what \nis called by gardeners its bleeding season. \n\nWhen the leaves are fully expanded, the great deter- \nmination of the sap is to these new organs. And hence \na tree which emits sap copiously from a wound whilst \nthe buds are opening, m ill no longer emit it in summer \nwhen the leaves are perfect ; but in the variable wea- \nther, towards the end of autumn, when the leaves are \nfalling, it will again possess the power of bleeding in \na very slight degree in the warmest days ; but at no \nother times. \n\nIu all these circumstances there is nothing analogous \nto the irritable action of animal systems. \n\nIn animal systems the heart and arteries are in con- \nstant pulsation. Their functions are unceasingly per- \n\n\n\n171 \n\nformed hi all climates, aud in all seasons ; in winter, as \nwell as in spring; upon the arctic snows, and under the \ntropical suns. They neither cease in the periodical noc- \nturnal sleep, common to most animals ; nor in the long \nsleep of winter, peculiar to a few species. The power \nis connected with animation, is limited to beings pos- \nsessing the means of voluntary locomation ; it co-exists \nwith the first appearance of vitality; it disappears only \nwith the last spark of life. \n\nVegetables maybe truly said to be living systems, in \nthis sense, that they possess the means of converting the \nelements of common matter into organized structures, \nboth by assimilation and reproduction ; but we must not \nsuffer ourselves to be deluded by the very extensive ap- \nplication of the word life, to conceive in the life of plants, \nany power similar to that producing the life of animals. \nIn calling forth the vegetable functions, common physi- \ncal agents alone seem to operate ; but in the animal sys- \ntem these agents are made subservient to a superior \nprinciple. To give the argument in plainer language, \nthere are few philosophers who would be inclined to as- \nsert the existence of any thing above common matter, \nany thing immaterial in the vegetable economy. Such \na doctrine is worthy only of a poetic form. The imagi- \nnation may easily give Dryads to our trees, and Sylphs \nto our flowers ; but neither Dryads nor Sylphs can be \nadmitted in vegetable physiology; and for reasons near- \nly as strong, irritability and animation ought to be ex- \ncluded. \n\nAs the operation of the different physical agents upon \nthe sap vessels of plants ceases, and the fluid becomes \nquiescent, the materials dissolved in it by heat, are de- \nposited upon the sides of the tubes now considerably \ndiminished in their diameter ; and in consequence of this \ndeposition, a nutritive matter is provided for the first \nwants of the plant in early spring, to assist the opening \nof their buds, and their expansion, when the motion from \nthe want of leaves is as yet feeble. \n\nThis beautiful principle in the vegetable economy was \nfirst pointed out by Dr. Darwin ; and Mr. Knigiit has \ngiven a number of experimental elucidations of it. \n\n\n\nAll\'. Kfii\xc2\xa3;lit made, numerous incisious into tlie albui \niium ol* the sycamoie and thebiicb, atditTerent lieiglits; \nand in cxaminini^ tlie sap that flowed from them, he \nfound it more sweet and mucihtginous in proportion as \nthe aperture from which it flowed was elevated ; which \nlie could ascribe to no other cause than to its having \ndissolved sugar and mucilage, which had been stored up \nthrough the winter. \n\nHe examined the alburnum in difterent poles of oak \nin the same forest ; of which some had been felled in \nwinter, and others in summer ; and he always found \nmost soluble matter in the wood felled in winter, and \nits specific gravity was likewise greater. \n\nIn all perennial trees this circumstance takes place ; \nand lii^eAvise in grasses and shrubs. The joints of the \nperennial grasses contain more saccharine and mucila- \nginous matter in winter than at any other season ; and \nthis is the reason why the liorin or Agrostis alba, which \nabounds in these joints, aftbrds so useful a winter \nfood. \n\nThe roots of shrubs contain the largest quantity of \nnourishing matter in the depth of winter ; and the bulb \nin all plants possessing it, is the recepticle in which nou- \nrishment is hoarded up during winter. \n\nIn annual plants the sap seems to be fully exhausted \nof all its nutritive matter by the production of flowers \nand seeds, and no system exists by which it can be pre- \nserved. \n\nWhen perennial grasses are cropped very close by \nfeeding cattle late in autumn, it has been often observed \nby farmers, that tliey never rise vigorously in the spring; \nand this is owing to the removal of that part of the stalk \nwhich would have afibrded them concrete sap, their first \nnourishment. \n\nShip builders prefer for their purposes that kind of \noak timber afforded by trees that have had their bark \nstripped off in spring, and wliich have been cut in the \nautumn or winter following. The reason of tlie supe- \nriority of this timber is, that tlie concrete sap is expend- \ned in the spring in the sprouting of the leaf; and the \ncirculation being destroyed, it is not formed anew ; and \n\n\n\nas \n\nilie wood having its pores free from saccharine matter, \nis less liable to undergo fermentation from the action of \nmoisture and air. \n\nIn perennial trees a new alburnum, and consccjuently \na new system of vessels, is annually produced, and the \nnutriment for the next year deposited in them ; so that \nthe new buds like the plume of the seed, are supplied \nwith a reservoir of matter essential to their first de- \nvelopment. \n\nThe old alburnum is gradually converted into heart- \nwood, and being constantly pressed upon by the expan- \nsive force of the new fibres, becomes harder, denser, \nand at length loses altogether its vascular structure ; and \nin a certain time obeys the common laws of dead mat- \nter, decays, decomposes, and is converted into aeriform \nand carbonic elements; into those principles from which \nit was originally formed. \n\nThe decay of the heart- wood seems to constitute the \ngreat limit to the age and size of trees. And in young \nbranches from old trees, it is much more liable to de- \ncompose than in similar branches from seedlings. This is \nlikewise the case with grafts. The graft is only nou- \nrished by the sap of the tree to which it is transferred ; \nits properties are not changed by it : the leaves, blos- \nsoms and fruits are of the same kind as if it had vege- \ntated upon its parent stock. The only advantage to be \ngained in this way, is the affording to a graft from an \nold tree a more plentiful and healthy food than it could \nhave procured in its natural state ; it is rendered for a \ntime more vigorous, and produces fairer blossoms and \nricher fruits, iiiii it partakes not merely of the obvi- \nous properties, but likewise of the infirmities and dis- \npositions to old age and decay, of the tree whence it \nsprung. \n\nThis seems to be distinctly shewn by the observations \nand experiments of Mr. Knight. He has, in a numl>er \nof instances, transferred the young scions and healthy \nshoots from old esteemed fruit-bearing trees to young \nseedlings. They flourished f(U- two or three years; but \nthey soon became diseased and sickly like their parent \ntrees. \n\nJt is from fliis cause that s-o many of the applr?s ftn-^ \n\n\n\n174 \n\nluei\'ly celebmted lor their taste and their uses in the \ninanulactiire of cider are gradually deteriorating, and \nmany will soon disappear. The golden pippin, the red \nstreak, and the moil, so excellent in the beginning of the \nlast century, are now in the extremest stage of their de- \ncay ^ and however carefully they are ingrafted, tliey \nmerely tend to multiply a sickly and exhausted variety. \n\nThe trees possessing the firmest and the least porous \nheart-wood are the longest in duration. \n\nIn general, the quantity of charcoal afforded by woods, \noflTers a tolerably accurate indication of their durability : \nthose most abundant in charcoal and earthy matter are \nmost permanent ; and those that contain the largest pro- \nportion of gaseous elements are the most destructible. \n\nAmongst our own trees, the chesnut and the oak are \npre-eminent as to durability ; and tlie chesnut affords \nrather more carbonaceous matter than the oak. \n\nIn old gothic buiblings these woods have been some- \ntimes mistaken one for the other; but they may be easily \nknown by this circumstance, that the pores in the albur- \nnum of the oak are much larger and more thickly set, \nand are easily distinguished ; whilst the pores in the \nchesnut require glasses to be seen distinctly. \n\nIn consequence of the slow decay of the heart- wood \nof the oak and chesnut, these trees under favourable cir- \ncumstances attain an age which cannot be much short of \n1000 years. \n\nThe beech, the ash, and the sycamore, most likely \nnever live half as long. The duration of the apple tree \nis not, probably, much more than 200 years ; but the \npear tree, according to Mr. Knight, lives through double \nthis period ; most of our best apples are supposed to \nhave been introduced into Britain by a fruiterer of Hen- \nry the Eighth, and they are now in a state of old age. \n\nThe oak and chesnut decay much sooner in a moist \nsituation, than in a dry and sandy soil ; and tlieir tim- \nber i\xc2\xab less firm. The sap vessels in such cases are more \nexpanded, though less nourishing matter is carried into \nthem ; and the general texture of the formations of wood \nnecessarily less firm. Such wood splits more easily, \nand is more liable to ])e affected by variations in the state \nM\' the atnic\xc2\xbbspliere. \n\n\n\n\nt Granite \ne tineis \n\n3 \'Mictxcotms Sftis \n\n4 Sie7tife \n3 Serpeitthte \n\n6 PlTflhlfTlf \n\n\n\n175 \n\n* \n\nThe same trees, in general, are much longer lived in \nthe northern than in the southern climates. The reason \nseems to be, that all fermentation and decomposition are \nchecked by cold; and at very low temperatures both \nanimal and vegetable matters altogether resist putrefac- \ntion : and in the northern winter, not only vegetable life, \nbut likewise vegetable decay must be at a stand. \n\nThe antiputrescent quality of cold climates is fully \nillustrated in the instances of the rhinoceros and mam- \nmoth lately found in Siberia, entire beneath the frozen \nsoil, in which they must probably have existed from the \ntime of the deluge. I examined a part of the skin of \nthe mammoth sent to this country, on which there was \nsome coarse hair ; it had all the chemical characters of \nrecently dried skin. \n\nTrees that grow in situations much exposed to winds, \nhave harder and firmer wood than such as are considera- \nbly sheltered. The dense sap is determined, by the \nagitation of the smaller branches, to the trunk and large \nbranches ; where the new alburnum formed is conse- \nquently thick and firm. Such trees abound in the crook- \ned limbs fitted for forming knee-timberj which is neces- \nsary for joining the decks and the sides of ships. The \ngales in elevated situations gradually act, so as to give \nthe tree the form best calculated to resist their effects. \nAnd the mountain oak rises robust and sturdy ; fixed \nfirmly in the soil, and able to oppose the full force of \nthe tempest. \n\nThe decay of the best varieties of fruit-bearing trees \nwhich have been distributed through the country by \ngrafts, is a circumstance of great importance. There is \nno mode of preserving them ; and no resourse, except \nthat of raising new varieties by seeds. \n\nWhere a species has been ameliorated by culture the \nseeds it affords^ other circumstances being similar, pro- \nduce more vigorous and perfect plants ; and in this way \nthe great improvements in the productions of our fields \nand gardens seem to have been occasioned. \n\nWheat in its indigenous state, as a natural production \nof the soil, appears to have been a very small grass : \nand the case is still more remarkable with the apple and \nthe plum. The crab seems to have ]>uen the parent of \n\n\n\n\nI \n\n\n\n\n176 \n\n* \n\nall our apples. And two fruits cau scarcely be coucei- \n\nved more diflerent in colour, size, and appearance than \n\nthe wild plum and the rich magnum bonum. \n\nThe seeds of plants exalted by cultivation always fur- \nnish large and improved varieties ; but the flavour, and \neven the colour of the fruit seems to be a matter of ac- \ncident. Thus a hundred seeds of the golden pippin \n"will all produce fine large-leaved apple trees, bearing \nfruit of a considerable size ; but the tastes and colours \nof the apples from each will be different, and none will \nbe the same in kind as those of the pippin itself. Som\xc2\xab \n"will be sweet, some sour, some bitter, some mawkish, \nsome aromatic ; some yellow, some green, some red, and \nsome streaked. All the apples will, however, be much \nmore perfect than those from the seeds of the crab, which \nproduce trees all of the same kind, and all bearing sour \nand diminutive fruit. \n\nThe power of the horticulturist extends only to the \nmultiplying excellent varieties by grafting. They can- \nnot be rendered permanent ; and the good fruits at pre- \nsent in our gardens, are the produce of a few seedlings, \nselected probably from hundreds of thousands ; the re- \nsults of great labour and industry, and multiplied expe- \nriments. \n\nThe larger and thicker the leaves of a seedling, and \nthe more expanded its blossoms, the more it is likely to \nproduce a good variety of fruit. Short-leaved trees \nshould never be selected ; for these approach nearer to \nthe original standard ; whereas the other qualities indi- \ncate the influence of cultivation. \n\nIn the general selection of seeds, it would appear that \nthose arising from the most highly cultivated varieties \nof plants, are such as give the most vigorous produce ; \nbut it is necessary from time to time to change, and as \nit were, to cross the breed. \n\nBy applying the pollen, or dust of the stamina, from \none variety to the pistil of another of the same species, \na new variety may be easily produced ; and Mr. Knight\'s \nexperiments seem to warrant the idea, that great advan- \ntages may be derived from this method of propagation. \n\nMr. Knight\'s large peas produced by crossing two \n\n\n\n177 \n\nvarieties, are celebrated amongst horticulturists, and. \nwill, I hope, soon be cultivated by farmers. \n\n1 have seen several of his crossed apples, which pro- \nmise to rival the best of those which are gradually dy- \ning away in the cider countries. \n\nAnd his experiments on the crossing of wheat, which \nis very easily effected, merely by sowing the different \nkinds together, lead to a result which is of considerable \nimportance. He says, in the Philosophical Transac- \ntions for 1799, " in the years 1795 and 1796, when al- \nmost the whole crop of corn in the island was blighted, \nthe varieties obtained by crossing alone escaped, though \nsown in several soils, and in very different situations. \'^ \n\nThe processes of gardening for increasing the num- \nber of fruit- bearing branches, and for improving the \nfruit upon particular branches, will all admit of eluci- \ndation from the principles that have been advanced in \nthis Lecture. \n\nBy making trees espaliers, the force of gravity is par- \nticularly directed towards the lateral parts of tlie branch- \nes, and more sap determined towards the fruit buds ; and \nhence they are more likely to bear when in a horizontal \nthan when in a vertical position. \n\nThe twisting of a wire, or tying a thread round a \nbranch has been often recommended as a means of ma- \nking it produce fruit. In this case the descent of the \nsap in the bark must be impeded above the ligature ; and \nmore nutritive matter consequently retained and appli- \ned to the expanding parts. \n\nIn engrafting, the vessels of the bark of the stock and \nthe graft cannot so perfectly come in contact as the al- \nburnous vessels, which are much more numerous, and \nequally distributed ; hence the circulation downwards is \nprobably impeded, and the tendency of the graft to evolve \nits fruit-bearing buds increased. \n\nBy lopping trees, more nourishment is supplied to the \nremaining parts ; for the sap flows laterally as well as \nperpendicularly. The same reasons will apply to ex- \nplain the increase of the size of fruits by diminishing \nthe number upon a tree. \n\nAs plants are capable of amelioration by peculiar me- \nthods of cultivation, and of having the natural term of \n\n\n\n178 . \n\niheir duration extended ; so, in conformity to the gene- \nral law of change, they are rendered unhealthy by be- \ning exposed to peculiar unfavourable circumstances, and \nliable to premature old age and decay. \n\nThe plants of warm climates transported into cold \nones, or of cold ones transported iulo warm ones, if not \nabsolutely destroyed by the change of situation, are uni- \nformly rendered unhealthy. \n\nFew of the tropical plants, as is well known, can be \nraised in this country, except in hot houses. The vine \nduring the whole of our summer may be said to be in a \nfeeble state with regard to health ; and its fruit, except \nin very extraordinary cases, always contains a supera- \nbundance of acid. The gigantic pine of the north, when \ntransported into the equatorial climates, becomes a de- \ngenerated dwarf ; and a great number of instances of the \nsame kind might be brought forward. \n\nMuch has been w ritten, and many very ingenious re- \nmarks have been made by different philosophers upon \nwhat have been called the habits of plants. Thus, in \ntransplanting a tree, it dies or becomes unhealthj\', un- \nless its position with respect to the sun is the same as \nbefore. The seeds brought from warm climates germi- \nnate here much more early in the season than the same \nspecies brought from cold climates. The apple tree \nfrom Siberia, where the short summer of three mouths \nimmediately succeeds the long winter, in England, usu- \nally puts forth its blossoms in the first year of its trans- \nplantation, on the appearance of mild weather; and is \noften destroyed by the late frosts of the spring. \n\nIt is not ditlicult to explain this principle so intimate- \nly connected with the healthy or diseased state of plants. \nThe organization of the germ, whether in seeds or buds, \nmust be different according as more or less heat, or al- \nternations of heat and cold, have afl\'ected it during its \nformation ; and the nature of its expansion must depend \nwholly on this organization. In a changeable climate \nthe formations will have been interrupted, and in dif- \nferent successive layers. In an equable temperature they \nwill liave been uniform ; and the operation of new and \nsudden causes will of course be severely felt. \n\nTlie disposilion of trees may, however, be chauged \n\n\n\ni79 \n\ngradually in many instances; and the operation of anew \nclimate in this way be made supportable. The myrtle, \na native of the south of Europe, inevitably dies if ex- \nposed in the early days of its grov^^th to the frosts of our \nwinter; but if kept in a green-house during the cold \nseasons for successive years, and gradually exposed to \nlow temperatures, it will, in an advanced stage of growth, \nresist even a very severe cold. And in the south and \nwest of England tiie myrtle flourishes, produces blos- \nsoms and seeds, in consequence of this process, as an \nunprotected standard tree ; and the layers from such \ntrees are much more hardy than the layers from myrtles \nreared within doors. \n\nThe arbutus, probably originally from similar culti- \nvation has become the principal ornament of the lakes \nof the south of Ireland. It thrives even in bleak moun- \ntain situations; and there can ])e little doubt but that the \noffspring of this tree inured to a temperate climate might \nbe easily spread in Britain. \n\nThe same princijiles that apply to the effects of heat \nand cold will likewise apply to the influence of moisture \nand dryness. The layers of a tree habituated to a moist \nsoil will die in a dry one : even though such a soil is \nmore favourable to the general growtli of the species. \nAnd, as was stated, page 132, trees that have been raised \nin the centre of woods, are sooner or later destroyed, if \nexposed in their adult state to blasts, in consequence of \nthe felling of the surrounding timber. \n\nTrees, in all cases, in which they are exposed in high \nand open situations to the sun, the winds, and the rain, \nas I just now noticed, become low and robust, exhibit- \ning curved limbs, but never straight and graceful trunks. \nShrubs and trees, on the contrary, which are too much \nsheltered, too much secluded from the sun and wind ex- \ntend exceedingly in height; but present at the same time \nslender and feeble branches, their leaves are pale and \nsickly, and in extreme cases they do not bear fruit.\' The \nexclusion of light alone is sufficient to produce this spe- \ncies of disease, as would appear from the experiments \nof Bonnet. This ingenious physiologist sowed three \nseeds of the pea in the same kind of soil : one he suf- \nfered to remain exposed to the free air ; the other he eii- \n\n\n\n\xc2\xab losetl in ;i lube of glass ; ami tlie (bird in a tube of \nAvood. Tbe pea in tlie tube of glass sprouted, and grew \nin a manner scarcely at all difterent from that under \nusual circumstances; but the plant in the tube of wood, \ndeprived of light, became white, and slender, and grew \nto a much greater height. \n\nThe plants growing in a soil incapable of supplying \nthem with sufficient manure or dead organized matter, \narc generally very low ; having brown or dark green \nleaves, and their woody fibre al)ounds in earth. Those \nvegetating in peaty soils, or in lands too copiously sup- \nplied with animal or vegetable matter, rapidly expand, \nproduce large bright green leaves, abound in sap, and \ngenerally blossom prematurely. \n\nWhere a land is too rich for corn it is not an uncom- \nmon practice to cut down tlie first stalks, as by these \nmeans its exuberance is corrected, and it is less likely \nto fall before the grain is ripe ; excess of poverty or of \nrichness is almost equally fatal to the hopes of the farm- \ner : and the true constitution of the soil for the best crop \nis that in whicli the earthy materials, the moisture and \nmanure, arc properly associated ; and in which the de- \ncomposable vegetable or animal matter does not exceed \none- fourth of the weight of tbe earthy constituents. \n\nThe canker, or erosion of the bark and wood, is a dis- \nease produced often in trees by a poverty of soil ; and \nit is invariably connected with old age. The cause \nseems to Jbe an excess of alkaline and earthy matter in \nthe descending sap. 1 have often found carbonate of \nlime on the edges of the canker in apple trees ; and ul- \nmin, which contains fixed alkali, is abundant in the can- \nker of the elm. The old age of a tree, in this respect, \nis faintly analogous to the old age of animals, in whicli \nthe secretions of solid bony matter arc always in excess, \nand the tendency to ossification great. \n\nThe common modes of attempting to cure the canker, \nare by cutting the edges of the bark, binding the new \nbark upon it, or laying on a plaster of earth ; but these \nmethods, though they have been much extolled, proba- \nbly do very little in producing a regeneration of the part. \nPerhaps the application of a weak acid to the canker \nmight be of use ; or, where the tree is of great value, it \n\n\n\n181 . \n\nmay be watered occasionally with a very diluted acid. \nTlie alkaline and earthy nature of the morbid secretion \nwarrants the trial ; but circumstances that cannot be \nforeseen may occur to interfere with the success of the \nexperiment. \n\nBesides the diseases having their source in the consti- \ntution of the plant, or in the unfavourable operation of \nexternal elements, there are many others perhaps more \ninjurious, depending upon the operations and powers of \nother living beings ; and such are the most difficult to\'^ \ncure, and the most destructive to the labours of the hus- \nbandman. \n\nParasitical plants of different species, which attach \nthemselves to trees and shrubs, feed on their juices, de- \nstroy their health, aiul finally their life, abound in all \nclimates ; and are perhaps, the most formidable of the \nenemies of the superior and cultivated vegetable species. \nThe mildew, which has often occasioned great ha- \nvock in our wheat crops, and which was particularly \ndestructive in 1804, is a species of fungus, so small as \nto require glasses to render its form distinct, and rapidly \npropagated by its seeds. \n\nThis has been shewn by various botanists ; and the \nsubject has received a full illustration from the enlight- \nened and elaborate researches of the President of the \niioyal Society. \n\nThe fungus rapidly spreads from stalk to stalk, fixes \nitself in the cells connected with the common tubes, and \ncarries away and consumes that nourishment which \nshould have been appropriated to the grain. \n\nNo remedy has as yet been discovered for this disease ; \nbut as the fungus increases by the diff\'usion of its seeds, \ngreat care should be* taken that no mildewed straw is \ncarried in the manure used for corn ; and in the early crop, \nif mildew is observed upon any of tlie stalks of corn, \nthey should be carefully removed and treated as weeds. \nThe popular notion amongst farmers, that a barberry- \ntree in the neighbourhood of a field of wheat often pro- \nduces the mildev/, deserves examination. This tree is \nfrequently covered with a fungus, which if it should be \nshewn to be capable of degenerating into the wheat fun-\' \ngus, would offer an easy explanation of tlie effect. \n\n\n\n482 \n\nThere is every reason to believe, from the researches \nof Sir Joseph Banks, that the smut in wheat is produ- \nced by a very small. fungus which fixes on the grain : \nthe products that it affords by analysis are similar to \nthose afforded by the puff-ball; and it is difficult to con- \nceive, that without the agency of some organized struc- \nture, so complete a change should be effected in the con- \nstitution of the grain. \n\nThe misletoe and the ivy, the moss and the lichen, in \nfixing upon trees, uniformly injure their vcigetative pro- \ncesses, though in very different degrees. They are sup- \nported from the lateral sap vessels, and deprive the bran- \nches above of a part of their nourishment. \n\nThe insect tribes are scarcely less injurious than the \nparasitical plants. \n\nTo enumerate all the animal destroyers and tyrants \nof the vegetable kingdom would be to give a catalogue \nof the greater number of the classes in zoology. Every \nspecies of plant, almost, is the peculiar resting place, or \ndominion of some insect tribe ; and from the locust, the \ncaterpillar, and snail, to the minute aphis, a wonderful \nvariety of the inferior insects are nourished, and live by \ntheir ravages upon the vegetable world. \n\nI have already referred to the insect which feeds on \nthe seed-leaf of the turnip. \n\nThe Hessian fly, still more destructive to wheat, has \nin some seasons threatened the United States with a fa- \nmine. And the French government is at this time* is- \nsuing decrees with a view to occasion the destruction of \nthe larvas of the grasshopper. \n\nIn general, wet weather is most favourable to the \npropagation of mildew, funguses, rust, and the small pa- \njasitical vegetables ; dry weather to the increase of the \ninsect tribes. Nature, amidst all her changes, is con- \ntinually directing her resources towards the production \nand multiplication of life ; and in the wise and grand \neconomy of the whole system, even the agents that ap- \npear injurious to the hopes, and destructive to the com- \nforts of man, are in fact ultimately connected with a more \nexalted state of his powers and his condition. His in- \n\n* January, 18 1 3*. \n\n\n\n183 \n\ntlustry is awakeiie<i, Iiis activity kept alive, even by the \ndefects of climates and season. By the accidents which \ninterfere with his eflbrts, he is made to exert his talents, \nto look farther into futurity, and to consider the vege- \ntable kingdom not as a* secure and inalterable inheri- \ntance, spontaneously providing for his wants ; but as a \ndoubtful and insecure possession, to be preserved only \nby labour, and extended and perfected by ingenuity. \n\n\n\nLECTUKE YL \n\n\n\nOf Manures of vegetable and animal Origin. Of the \nManner iyi which they become the nourishment of the \nPlant. Of Fermentation and Putrefaction. Of the \ndifferent Species of Manures of Vegetable Origin ; \nof the different Species of animal Origin, Of mix- \ned Manures. General Principles with resjject to the \nUse and Application of such Manures. \n\nX HAT certain vegetable and animal substances intro- \nduced into the soil accelerate vegetation and increase \nthe produce of crops, is a fact known since the earliest \nperiod of agriculture ; but the manner in which manures \nact, the best modes of applying them, their relative va- \nlue and durability, are still subjects of discussion. In \nthis Lecture I shall endeavour to lay down some settled \nprinciples on these objects ; they are capable of being \nmaterially elucidated by the recent discoveries in che- \nmistry ; and I need not dwell on their great importance \nto farmers. \n\nThe pores in the fibres of the roots of plants are so \nsmall, tliat it is with difficulty they can be discovered \nby the microscope ; it is not therefore proba])le, that solid \nsubstances can pass into them from the soil. 1 tried an \nexperiment on this subject ; some impalpable powdered \ncharcoal procured by washing gunpowder, and dissipa- \nting the sulphur by heat, was placed in a phial contain- \ning pure water, in which a plant of peppermint was \ngrowing : the roots of the plant were pretty generally in \ncontact with the charcoal. The experiment was made \nin the beginning of May, 1805 ; the growth of the plant \nwas very vigorous during a fortniglit, when it was taken \nout of the phial : the roots were cut through in different \nparts ; but no carbonaceous matter could be discovered \nin them, nor were the smallest filnils blackened by \n\n\n\n185 \n\ncharcoal, though this must have been the case had the \ncharcoal been absorbed in a solid form. \n\nNo substance is more necessary to plants than car- \nbonaceous matter; and if this cannot be introduced into \nthe organs of plants except in a state of solution, there \nis every reason to suppose that other substances less es- \nsential will be in the same case. \n\nI found, by some experiments made in 1804, that \nplants introduced into strong fresh solutions of sugar, \nmucilage, tanning principle, jelly, and other substances \ndied ; but that plants lived in the same solutions after \nthey had fermented. At that time, 1 supposed that fer- \nmentation was necessary to prepare the food of plants ; \nbut I have since found that the deleterious effect of the \nrecent vegetable solutions was owing to their being too \nconcentrated ; in consequence of which the vegetable or- \ngans were probably clogged with solid matter, and the \ntranspiration by the leaves prevented. In the beginning \nof June, in the next year, 1 used solutions of the same \nsubstances, but so much diluted, that there was only \nabout one-two hundreth part of solid vegetable or ani- \nmal matter in the solutions. Plants of mint grew luxu- \nriantly in all these solutions ; but least so in that of the \nastringent matter. I watered some spots of grass in a \ngarden with the different solutions separately, and a \nspot witli common water : the grass watered with solu- \ntions of jelly, sugar, and mucylage, grew most vigorous- \nly; and that watered with the solution of the tanning \nprinciple grew better thau that watered with common \nwater. \n\nI endeavoured to ascertain wlietlier soluble vegetable \nsubstances passed in an unchanged state into the roots \nof plants, by comparing the products of the analysis of \nthe roots of some plants of mint that had grqwn, some \nin common water, some in a solution of sugar. One \nhundred and twenty grains of the roots of the mint which \ngrew in the solution of sugar, afforded five grains of \npale green extract, which had a sweetish taste, but which \nslightly coagulated by the action of alcohol. One hun- \ndred and twenty grains of the roots of the mint which \nhad grown in (common water yielded three grains and a \nhalf of extract, which was of a deep olive colour ; its \n\nA a \n\n\n\n186 \n\ntaste was sweetish, but more astriiigent thati tliat of the \nother extract, and it coagulates more copiously with al- \ncoliol. \n\nThese results though hot quite decisive, favour the \nopinion that sohible matters pass unaltered into tlie roots \nof plants ; and the idea is confirmed by the circumstance \nthat the radical fibres of plants made to grow in infu- \nsions of madder are tinged red, and it may be consider- \ned as almost proved by the fact, that substances which \nare even poisonous to vegetables are absorbed by them. \nI introduced the roots of a primrose into a weak solution \nof oxide of iron in vinegar, and suflcred it to remain in \nit till the leaves became yellow ; the roots were then \ncarefully washed in distilled water, bruised, and boiled \nin a small quantity of the same fluid : the decoction of \nthem passed through a filtre was examined by the test \nof infusion of nut-galls ; the decoction gained a strong \ntint of purple, which proves that solution of iron had \nbeen taken up by the vessels or pores in the roots. \n\nVegetable and animal substances deposited in the soil, \nas is shewn by universal experience, are consumed du- \nring the process of vegetation ; and they can only nou- \nrish the plant by aiTording solid matters capable of be- \ning dissolved by water, or gaseous substances capable of \nbeing absorbed by the fluids in the leaves of vegetables; \nbut such parts of them as are rendered gaseous, and that \npass into the atmosphere, must produce a comparative- \nly small eflect, for gases soon become difl[\'used through \nthe mass of the surrounding air. The great object in \nthe application of manure should be to make it afford \nas much soluble matter as possible to the roots of the \nplant; and that in a slow and gradual manner, so that \nit may be entirely consumed in .forming its sap and or- \nganized parts. \n\nMucilaginous, gelatinous, saccharine, oily, and extrac- \ntive fluids, and solution of carbonic acid in water, are \nsubstances that in their unchanged states contain almost \nall the principles necessary for the life of plants ; but \nthere are few cases in which they can be applied as ma- \nnures in their pure forms ; and vegetable manures, in \ngeneral, contain a great excess of fibrous and insoluble \nmatter, which nuist undergo chemical changes before \nthey can become the iood of plants. \n\n\n\nIt will he. proper (o lake a scientific view ol" tin uaim* \nof these changes ; of tlio causes which occasion them, \nand which accelerate or retard them ; and of the pro- \nducts they atibrd. \n\nIf any fresh vegetable matter which contains sugar, \nmucilage, starch, or otiier of the vegetable compounds \nsoluble in water be moistened and exposed to air, at a \ntemperature from 55^ to 80\xc2\xb0, oxygene will soon be .ab- \nsorbed, and carl)onic acid formed : heat will be produ- \nced, and clastic fluids principally carbonic acid, gaseous \noxide of carbon, and hydro-carbonate will be evolved ; \na dark coloured liquid, of a slightly sour or bitter taste, \nwill likewise be formed; and if the process lie suffered \nto continue for a time sufficiently long, nothing solid will \nremain, except earthy and saline matter, coloured black \nby charcoal. \n\nThe dark-coloured fluid formed in the fermentation \nalways contains ascetic a\'cid; and when albumen or glu- \nten exists in the vegetable substance, it likewise contains \nvolatile alkali. \n\nIn proportion as there is more gluten, albumen, or \nmatters soluble in water in the vegetable substances ex- \nposed to fermentation, so in proportion, all other circum- \nstances being equal, will the process be more rapid. \nPure woody fibre alone undergoes a change very slow- \nly; but its tex^ire is broken down, and it is easily resol- \nved into new elements, when mixed with substances \nmore liable to change, containing more oxygene and iiy- \ndrogene. Volatile and fixed oils, resins and wax, are \nmore susceptible of change than Avoody fibre, wlien ex- \nposed to air and water; but much less liable than the \nother vegetable compounds ; and even the most inflam- \nmable substances by the absorption of oxygene, become \ngradually soluble in water. \n\nAnimal matters in general are more liable to decom- \npose than vegetable sui)stances ; oxygene is absorbed, \nand carbonic acid and ammonia formed in the process \nof their putrefaction. They produce foited com|)oinid \nelastic fluids, and likewise azote : they afford dark-co- \nloured acid and oily fluids, and leave a residuum of salts \nand earths mixed with carbonaceous matter. \n\nThe principal substances which constitute the differ- \n\n\n\ne.nt parts of iuiiaiuls, or which arc found in their blooil, \ntheir secretions, or their excrements^ are gelatine, fibrine, \nmucus, fatty, or oily matter, albumen, urea, uric acid, \nand diiferent acid, saline, and earthy matters. \n\nOf these gelatine is the substance which when com- \nbined with water forms jelly. It is very liable to pu- \ntrefaction. Accordini; to M. M. Gay Lussac and The- \niiard^ it is composed of \n\n47.88 of carbon. \n27.207 - oxyj^ene. \n\n7.914 - hydrogene. \n16.998 \n\nThese proportions cannot be considered as definite, \nfor they do not bear to each otiicr the ratios of any sim- \nple multiples of the number representing the elements ; \nthe case seems to be the same with other animal com- \npounds : and even in vegetable substances, in general, \nas appears from the statements given in the Third Lec- \nture, the proportions are far from having the same sim- \nple relations as in tlie binary compounds capable of be- \ning made artificially, such as acids, alkalies, oxides, \nand in salts. \n\nFibrine constitutes the basis of the muscuLar fibre of \nanimals, and a similar substance may be obtained from \nrecent fluid blood ; by stirring it with a stick the fibrine \n>vill adhere to the stick. It is not solubl\xc2\xbbin water; but \nby the action of acids, as Mr. Katchett has shewn, it be- \ncomes soluble, and analogous to gelatine. It is less \ndisposed to putrefy than gelatine. According to M. M. \nGay Lussac and Thcnard, 100 parts of fibrine contain \nOf Carbon - 53.360 \nOxygene - 19.685 \nHydrogene 7.021 \n\nAzote - 19.934 \n\nMucus is very analogous to vegetable gmn in its cha- \nracters ; and as Dr. Bostock has stated, it may be ob- \ntained by evaporating saliva. No experiments have \nbeen made upon its analysis ; but it is probably similar \nto gum in composition. It is ca|)able of undergoing pu- \ntrefjiction, but less rapidly than fibrine. \n\n\xe2\x80\xa2Animal fat anil oils have not been accurately analy- \nzed j but there is great reason to suppose that their com- \n\n\n\n189 \n\nposition is analogous to that of similar substances from \nthe vegetable kingdom. \n\nAlbumen has been already referred to, and its analy- \nsis stated in the Third Lecture. \n\nUrea may be obtained by the evaporation of human \nurine, till it is of the consistence of a syrup; and the ac- \ntion of alcohol on the crystalline substance which forms \nwhen the evaporated matter cools. In this way a solu- \ntion of urea in alcohol is procured, and the alcohol may \nbe separated from the urea by heat. Urea is very solu- \nble in water, and is precipitated from water by diluted \nnitric acid in the form of bright pearl-coloured crystals ; \nthis property distinguishes it from all other animal sub- \nstances. \n\nAccording to Fourcroy and Vauquelin, 100 parts of \nurea when distilled yield \n\n92.027 parts of carbonate of ammonia. \n4.608 carburetted hydrogene gas. \n3.225 of charcoal. \nUrea, particularly when mixed with albumen or gela- \ntine, readily undergoes putrefaction. \n\ntiric acidj as has been shewn by Dr. Egan, may be \nobtained from human urine by pouring an acid into it ; \nand it often falls down from urine in the form of brick- \ncoloured crystals, it consists of carbon, hydrogene, \noxygene, and azote : but their proportions have not yet \nbeen determined. Uric acid is one of the animal sub- \nstances least liable to undergo the process of putrefac- \ntion. \n\nAccording to the different proportions of these princi- \nples in animal compounds, so are the changes they un- \ndergo different. When there is much saline or earthy \nmatter mixed or combined with them, the progress of \ntheir d\'^composition is less rapid than when they are \nprincipally composed of fibrine, albumen, gelatine, or \nurea. \n\nThe ammonia given off from animal compounds in \nputrefaction may be conceived to be formed at the time \nof their decomposition by the combination of hydrogene \nand azote ; except this matter, the other products of pu- \ntrefaction are analogous to those afforded by the fer- \nmentation of vegetable substances; and the soluble sub- \nstances formed abound in the elements, which are the \n\n\n\n190 \n\nconstitucut parts of vegetables, in carbon, hydrogene, \nand oxygene. \n\nWliencver manures consist principally of matter solu- \nble in water, it is evident that their fermentation or pu- \ntrefaction should be prevented as much as possible ; and \nthe only cases in which these processes can be useful, \nare wlien the manure consists principally of vegetable or \nanimal fibre. The circumstances necessary for the pu- \ntrefaction of animal substances are similar to those re- \nquired for the fermentation of vegetable substances ; a \ntemperature above the freezing point, the presence of \nwater, and the presence of oxygene, at least in the first \nstage of the process. \n\nTo prevent manures from decomposing, they should \nbe preserved dry, defended from the contact of air, and \nkept as cool as possible. \n\nSalt and alcohol appear to owe their powers of pre- \nserving animal and vegetable substances to their attrac- \ntion for water, by which they prevent its decomposing \naction, and likewise to their excluding air. The use of \nice in preserving animal substances is owing to its keep- \ning their temperature low. The efficacy of M. Appert\'s \nmethod of preserving animal and vegetable substances, \nan account of which has been lately published, entirely \ndepends upon the exclusion of air. This method is by \nfilling a vessel of tin plate or glass with the meat or ve- \ngetables ; soldering or cementing the top so as to render \nthe vessel air tight ; and then keeping it half immersed \nin a vessel of boiling water for a sufficient time to ren- \nder the meat or vegetables proper for food. In this last \nprocess it is probable that tho small quantity of oxygene \nremaining in the vessel is absorbed ; for on opening a \ntinned iron canister which had been filled with raw beef \nand exposed to hot water the day before, I found that \nthe minute quantity of clastic fluid which could be pro- \ncured from it, was a mixture of carbonic acid gas and \nazote. \n\nWhere meat or vegetable food is to be preserved on \na large scale, for the use of the navy or army for in- \nstance, I am inclined to believe, that by forcibly throw- \ning a quantity of carbonic acid, hydrogene, or azote, into \ntlie vessel, by means of a compressing pump, similar to \nthat used for making artificial Seltzer water, any change \n\n\n\n191 \n\nill the substance would be more ettectually prevented. \n\\So elastic fluid in this case would have room to form \nby the decomposition of the meat ; and the tightness \nand strength of the vessel would be proved by the pro- \ncess. No putrefaction or fermentation can go on with- \nout the generation of elastic fluid ; and pressure would \nprobably act with as much efficacy as cold in the preser- \nvation of animal or vegetable food. \n\nAs different manures contain different proportions of \nthe elements necessary to vegetation, so they require a \ndifferent treatment to enable them to produce their full \neffects in agriculture. 1 shall therefore describe in de- \ntail the properties and nature of the manures in common \nuse, and give some general views respecting the best \nmodes of preserving and applying them. \n\nAll green succulent plants contain saccharine or mu- \ncilaginous matter, with woody fibre, and readily ferment. \nThey cannot, therefore, if intended for manure, be used \ntoo soon after their death. \n\nWhen gree7i crops arc to be employed for enriching \na soil, they should be ploughed in, if it be possible, \nwhen in flov/er^ or at the time the flower is beginning to \nappear, for it is at this period that tliey contain the \nlargest quantity of easily soluble matter, and that their \nleaves are most active in forming nutritive matter. \nGreen crops, pond weeds, the paring of hedges or ditches, \nor any kind of fresh vegetable matter, requires no pre- \nparation to fit them for manure. The decomposition \nslowly proceeds beneath the soil ; the soluble matters are \ngradually dissolved, and the slight fermentation that goes \non checked by the want of a free communication of air, \ntends to render the woody fibre soluble without occasion- \ning the rapid dissipation of elastic matter. \n\nWhen old pastures are broken up and made arable, \nnot only has the soil been enriched- by the death and \nslow decay of the plants which have left soluble matters \nin the soil; but the leaves and roots of the grasses liv- \ning at the time and occupying so large a part of the \nsurface, afford saccharine, mucilaginous, and extractive \nmatters, which become immediately the food of the crop, \nand the gradual decomposition affords a supply for suc- \ncessive years. \n\n\n\nIli2 \n\nRajm cake, which is used with great success as a ma- \nnure, contains a large quantity of mucilage, some albu- \nminous matter, and a small quantity of oil. This ma- \nnure should be used recent, and kept as dry-as possible \nbefore it is applied. It forms an excellent dressing for \nturnip crops ; and is most oeconomically applied by be- \ning thrown into the soil at the same time with the seed. \nWhoever wishes to see this practice in its highest de- \ngree of perfection, should attend Mr. Coke\'s annual \nsheep-shearing at Holkham. \n\nMalt dust consists chiefly of the infant radicle sepa- \nrated from the grain. I have never made any experi- \nment upon this manure ; but there is great reason to sup- \npose it must contain saccharine matter, and this will ac- \ncount for its powerful eftccts. Like rape cake it should \nbe used as dry as possible, and its fermentation prevented. \n\nLinseed cake is too valuable as a food for cattle to be \nmuch employed as a manure ; the analysis of linseed \nwas referred to in the Third Lecture. The water in \nwhich ^0^ and hemj) are steeped for the purpose of ob- \ntaining the pure vegetable iibre, has considerable ferti- \nlizing powers. It appears to contain a substance ana- \nlogous to albumen, ancl likewise much vegetable extrac- \ntive matter. It putrefies very readily. A certain de- \ngree of fermentation is absolutely necessary to obtain \nthe flax and hemp in a proper state ; the water to which \nthey have been exposed should therefore be used as a \nmanure as soon as the vegetable fibre is removed from it. \n\nSea weeds f consisting of diflerent species of fuci, al- \ngjE, and conferva\'., are much used as a manure on the \nsea coasts of Britain and Ireland. By digesting the \ncommon fucus, which is the sea weed usually most abun- \ndant on the coast, in boiling water, I obtained from it \none-eighth of a gelatinous substance which had charac- \nters similar to mucilage. A quantity distilled gave \nnearly four-iifths of its weight of water, but no ammo- \nnia ; the water had an empyreumatic and slightly sour \ntaste ; the ashes contained sea salt, carbonate of soda, \nand carbonaceous matter. The gaseous matter afforded \nwas small in quantity, principally carbonic acid and gas- \neous oxide of carbon, witli a little hydro-carbonate. \nThis manure is transient in its effects, and does not last \n\n\n\n193 \n\nfor more than a single crop, which is easily accounted \nfor from the lar\xc2\xa3;c quantity of water, or the elements of \nwater, it contains. It decays without producing heat \nwlien exposed to tlic atmosphere, and seems, as it were, \nto melt down and dissolve away. 1 have seen a large \nheap entirely destroyed in less than two years, nothing \nremaining l)ut a little hlack iihrous matter. \n\nI suffered some of the firmest part of a fucus to remain \niu a close jar, containing atmospheric air, for a fortnight : \nin this time it had become very much shrivelled ; the \nsides of the jar were lined with dew. The air examined \nwas found to have lost oxygene, and contained carl)onic \nacid gas. \n\nSea weed is sometimes suflered to ferment before it \nis used ; but this process seems wholly unnecessary, for \nthere is no fibrous matter rendered soluble in the pro- \ncess, and a part of the manure is lost. \n\nThe best farmers in the west of England use it as \nfresh as it can be procured ; and the practical results \nof this mode of applying it are exactly conformable to \nthe theory of its operation. The carbonic acid formed \nby its incipient fermentation must be partly dissolved \nby the water set free in the same process ; and thus be- \ncome capable of absorption by the roots of plants. \n\nThe effects of the sea weed, as manure, must princi- \npally depend upon this carbonic acid, and upon tlic so- \nluble mucilage the weed contains ; and I found that some \nfucus which had fermented so as to have lost about half \nits weight, afforded less tlian one-twelfth of mucilaginous \nmatter ; from which it may be fairly concluded that some \nof this substance is destroyed in fermentation. \n\nJhy straw of wheat, oats, barley, beans, and ])eas, \nand spoiled hay, or any other similar kind of dry vege- \ntable matter, is, in all cases, useful manure. In gene- \nral, such substances are made to ferment before th(iy arc \nemployed, though it may be doulited whether the prac- \ntice should be indiscriminately adoi>ted. \n\nFrom 400 grains of dry barley straw 1 obtained eight \ngrains of matter soluble in water, which had a brown \ncolour, and tasted like mucilage. \xe2\x80\xa2 From 400 grains of \nwheateu straw I obtained five grains of a similar sub- \nstance> \n\nB h \n\n\n\n194 \n\nTheir (an ho, no doubt Unit tlic straw of (liHevcntcroixs \nIinmcdiaU\'ly |)loiii;\'ho(l into the \xc2\xa3;rouiul allords noun.sh- \nnicnt to i\xc2\xbblanLs; hut tlunr is an ohjrciion to this uioihod \nof usiiii; straw from the difficulty of luiryinj; loui; straw, \nand from its renchuini:; the, husbaiulry foul. \n\nWhen straw is made to ferment, it liccomcs a more \ninanai;eahle nianure; Init there is likewise, on the whole, \na i^reat loss of nutritive matter. More manure is per- \nliaps sup[)lied for a siiij^le crop; !>nt the land is less im- \nproved than it wonid he, supposini; the whole of the ve- \nj^etable matter could be iinely divided and mixed with \nthe soil. \n\nIt is usual to carry straw that can be employed for no \nother purpose to the dunghill, to ferment, and decom- \npose ; but it is worth experiment, whether it may not be \nmore economically applied when chopped small by a \nproper mat hine, and kept dry till it is plouti;hejl in for \nthe use of a crop. li\xc2\xbb this case, thoniijh it would decom- \npose much more slowly, and produce less effect at first, \nyet its inlluence would be mu( h more lasting. \n\nMere wood if fibre seems to be the only vegetable mat- \nter that reqtiires fermentation to render it nutritive to \nplants. Tanners\' spent bark is a substance of this kind. \nMr. Vouui;\', in his excellent Kssay on Manures, which \ngained him the Hedfordian nu\'dal of the Hath Agricul- \ntural Society, states, ^\' that si)ent bark seemed rather to \ninjure than assist vegetation;"\'\' which he attributes to \nthe astringent matter that it contains. Hut, in fact, it is \nfreed from all soluble substances, by the operation of \nwater in the tan- pit; and if injurious to vegetation, the \nelVect is prohably owing to its agency u[\xc2\xbbon water, or to \nits mechanical etVects. It is a substance very absorbent \nand retenti^ e of moisture, and yet not penetrable by the \nroots of plants. \n\nInert peatu matter is a substance of the same kind. It \nrenmijis for years exposed to water and air without un- \ndergoing change, and in this state yields little or no nou- \nrishment to plants. \n\nAVoody llbre will not ferment unless some substances \nare mixed with it, which act the same part as the muci- \nlage, sugar, and extractive or albuminous matters, with \nAviiich it is iisnallv associated in herbs and succulent vc- \n\n\n\n195 \n\ngetabies. Lord Meadowbank has, judiciousiy recom \nmended a mixture of common farm-yard dung for the \npurpose of bringing peats into fermentation; any putres- \ncible or fermentable substance will answer the end ; and \nthe more a substance heats, and the more readily it fer- \nments, the better will it be fitted for the purpose. \n\nLord Meadowbank states, that one part of dung is \nsufficient to bring three or four parts of peat into a state \nin which it is fitted to be applied to land ; but of course \nthe quantity must vary according to the nature of the \ndung and of the peat. In cases in which some living \nvegetables are mixed with the peat, the fermentation \nwill be more readily eflfected. \n\nTanners\' spent bark, shavings of wood and saw-dust, \nwill probably require as much dung to bring them into \nfermentation as the worst kind of peat. \n\nWoody fibre may be likewise prepared so as to be- \ncome a manure, by the action of lime. This subject I \nshall discuss in the next Lecture, as it follows natural- \nly another series of facts, relating to the eflects of Ihne \nin the soil. \n\nIt is evident from the analysis of woody fibre by M. \nM. Gay Lussac andThenard, (which shews that it con- \nsists principally of the elements of water and carbon, the \ncarbon being in larger quantities than in the other vege- \ntable compounds) that any process which tends to ab- \nstract carbonaceous matter from it, must bring it nearer \nin composition to the soluble principles ; and this is done \nin fermentation by the absorption of oxygene, and pro- \nduction of carbonic acid ; and a similar cftect, it will be \nshewn, is produced by lime. \n\nWood-ashes, imperfectly formed, that is, wpod-ashes \ncontaining much charcoal, are said to have been used \nwith success as a manure. A part of their eflects may \nbe owing to the slow and gradual consumption of the \ncharcoal, which seems capable, under other circum- \nstances than those of actual combustion, of absorbing \noxygene so as to become carl)onic acid. \n\nIn April, 1803, I enclosed some well- burnt charcoal \nin a tube half filled with pure water, and half with com- \nmon air; the tube was hermetically sealed, 1 opened \nthe tube under pure water, in the spring of 1804, at a \n\n\n\nmo \n\niiUie wlii\'u iho iUiuospIio-iic. icnipoiaLiiie ami pleasure \nwtue nrai ly the- sanlie as at the commencement of the ex- \nperiment. Some water rushed in ; and on expelling a \nlittle air ])y heat from the tube, and analyzing it, it was \nfound to contain only seven percent, of oxygene. The \nwater in the tuhe, when mixed with lime-water, produ- \nced a copious precii>itate; so that carbonic acid had evi- \ndently been formed and dissolved by tlie water. \n\nManures from animal substances, in general, require \nno chemical preparation to fit them for the soil. The \ngreatobjectof the farmer is to blend them with the earthy \nconstituents in a proper state of division, and to prevent \ntheir too rapid decompositioti. \n\nThe entire parts of the muscles of land animals are \nnot commonly used as manure, though there are many \ncases in wliich such an application might be easily made. \nHorses, dogs, sheep, deer, and other quadrupeds that \nhave died accidentally, or of disease, after their skins \narc separated, are often sullered to remain exposed to \nthe air, or immersed in water, till they are destroyed by \nbirds or beasts of prey, or entirely decomposed ; and in \nthis case, most of their organi/alde matter is lost for \nthe land in which they lie, and a considerable portion \nof it employed in giving off noxious gases to the atmo- \nsphere. \n\nBy covering dead animals with five or six times their \nbulk of soil, mixed with one part of lime, and sutlering \nthem to remain for a few months ; their decomposition \nwould impregnate the soil with soluble matters, so as to \nrender it an excellent manure; and by mixing a little \nfresh quick lime Avith it at the time of its removal, the \ndisagreeable ellluvia will be in a great measure destroy- \ned ; and it might be applied in the same way as any \nother manure to crops. \n\nFiifh forms a powerful manure, in whatever state it \nis applied ; but it cannot be ploughed in two fresii, though \nthe quantity should be limited. Mr. Young records an \nexperiment, in which herrings spread over a field, and \nploughed in for wheat, produced so rank a crop, that it \nwas entirely laid before harvest. \n\nThe refuse pilchards in Cornwall are used throughout \nthe county as a manure, with excellent effects. They \n\n\n\nare usually mixed with sand or soil, and sometimes w ith \nsea weed, to prevent them from raising too luxuriant a \ncrop. The effects are perceived for several years. \n\nIn the fens of Lincolnshire, Cambridgeshire, and \nNorfolk, the little fishjes called sticklebacks, are caught \nin the shallow waters in such quantities, that they form \na great article of manure in the land bordering on the \nfens. \n\nIt is easy to explain the operation of fish as a manure. \nThe skin is principally gelatine ; which from its slight \nstate of cohesion, is readily soluble in water : fat or oil \nis always found in fishes, either under the skin or in \nsome of the viscera ; and their fibrous matter contains \nall the essential elements of vegetable substances. \n\nAmongst oily substances, blubber has been employed \nas a manure. It is most useful when mixed with clay, \nsand, or any common soil, so as to expose a large sur- \nface to the air, the oxygene of which produces soluble \nmatter from it. Lord Somerville used blubber with \ngreat success at his farm in Surrey. It was made into \na heap with soil, and retained its powers of fertilizing \nfor several successive years. \n\nThe carbon and hydrogene abounding in oily sub- \nstances, fully account for their effects ; and their dura- \nbility is easily explained from the gradual manner in \nwhich they change by the action of air and water. \n\nBones are much used as a manure in the neighbour- \nhood of London. After being broken, and boiled for \ngrease, they are sold to the farmer. The more divided \nthey are, the more powerful are their effects. The ex- \npense of grinding them in a mill would probably be re- \npaid by the increase of their fertilizing powers ; and in \nthe state of powder they might be used in the drill Iius- \nbandry, and delivered with the seed, in the same man- \nner as rape cake. \n\nBone dust, and bone shavings, the refuse of the turn- \ning manufacture, may be advantageously employed in \nthe same way. \n\nThe basis of Bone is constituted by earthy salts, prin- \ncipally phosphate of lime, with some carbonate of lime \nand phosphate of magnesia ; the easily decomposable \nsubstances in bone are fat, gelatine, and cartilage, which \nseems of the same nature as coagulated albumen. \n\n\n\n198 \n\n\n\nAccording to the analysis of Fourcroy and Vauqueiin, \nox bones are composed \n\nOf decomposable animal matter - 51 \n\n\xe2\x80\x94 phosphate of lime . - - 37.7 \n\n\xe2\x80\x94 carbonate of lime - - - 10 \n\n\xe2\x80\x94 phosphate of Magnesia - - 1.3 \n\n\n\n100 \n\n\n\nM. Merat Guillot has given the following estimate of \nthe composition of the bones of different animals. \n\n\n\nBone of Calf \nHorse \n\n\n\nSheep \n\nElk \n\nHog \n\nHare \n\nPullet \n\nPike \n\nCarp \n\nHorses\' teeth \nIvory - - \n\n\n\nPhosphate of l Carbonate of \nLime. Lime. \n\n\n\n54 \n\n67.5 \n\n70 \n\n90 \n\n52 \n\n85 \n\n72 \n\n64 \n\n45 \n\n85.5 \n\n64 \n\n\n\n1.25 \n5 \n1 \n1 \n1 \n1.6 \n1 \n5 \n\n20.5 \n1 \n\n\n\nThe remaining parts of the 100 must be considered \nas decomposable animal matter. \n\nHoi^ is a still more powerful manure than bone, as \nit contains a larger quantity of decomposable animal \nmatter. From 500 grains of ox horn, Mr. Hatchett ob- \ntained only 1.5 grains of earthy residuum, and not quite \nhalf of this was phosphate of lime. The shavings or \nturnings of horn form an excellent manure, though they \nare not suflBciently abundant to be in common use. The \nanimal matter in them seems to be of the nature of co- \nagulated albumen, and it is slowly rendered soluble by \nthe action of water. The earthy matter in horn, and \nstill more that in bones, prevents the too rapid decom- \nposition of the animal matter, and renders it very dura- \nble in its effects. \n\nHair, woollen rags, and feathers are all analogous in \nromposition, and principally consist of a substance simi- \n\n\n\n199 \n\nlar to albumen, united to gelatine. This is shewn by \nthe ingenious researches of Mr. Hatchett. The theory \nof their operation is similar to that of bone and horn \nshavings. \n\nThe refuse of the different manufactures of sHn and \nleather form very useful manures ; such as the shavings \nof the currier, furriers\' clippings, and the offals of \nthe tan-yard, and of the glue- maker. The gelatine con- \ntained in every kind of skin is in a state fitted for its \ngradual solution or decomposition ; and when buried in \nthe soil, it lasts for a considerble time, and constantly \naffords a supply of nutritive matter to the plants in its \nneighbourhood. \n\nBlood contains certain quantities of all the principles \nfound in other animal substances, and is consequently \na very good manure. It has been already stated that it \ncontains fibrine ; it likewise contains albumen : the red \nparticles in it which have been supposed by many fo- \nreign chemists to be coloured by iron in a particular \nstate of combination with oxygene and acid matter, Mr. \nBrande considers as formed of a peculiar animal sub- \nstance, containing very little iron. \n\nThe scum taken from the boilers of the sugar bakers, \nand which is used as manure, principally consists of \nbullock\'s blood, which has been employed for the pur= \npose of separating the impurities of common brown su- \ngar, by means of the coagulation of its albuminous mat\xc2\xbb \nter by the heat of the boiler. \n\nThe different species oicoralsy coralines, and sponges f \nmust be considered as substances of animal origin. \nFrom the analysis of Mr. Hatchett, it appears that all \nthese substances contain considerable quantities of a \nmatter analogous to coagulated albumen ; the sponges \nafford likewise gelatine. \n\nAccording to Merat Guillot, white coral contains \nequal parts of animal matter and carbonate of lime ; red \ncoral 46.5 of animal matter, and 53.5 of carbonate of \nlime ; articulated coraline 51 of animal matter, and 49 \nof carbonate of lime. \n\nThese substances are, I believe, never used as ma- \nnure in this country, except in cases when they are ac- \ncidently mixed with sea weed ; but it is probable that \n\n\n\ntlie coijilines might be advantageously employed, as they \nare found in considerable quantity on the rocks, and bot- \ntoms of the rocky pools on many parts of our coast, \nwhere the land gradually declines towards the sea; and \nthey might be detached by hoes, and collected without \nmuch trouble. \n\nAmongst excrementations, animal substances used as \nmanures, urine is the one upon which the greatest num- \nber of chemical experiments have been made, and the \nnature of which is best understood. \n\nThe urine of the cow contains, according to the ex- \nperiments of Mr. Brande, \n\nWater 65 \n\nPhosphate of lime - - - 3 \n\nMuriates of potassa and ammonia 15 \n\nSulphate of potassa - - 6 \n\nCarbonates, potassa, and ammonia 4 \n\nUrea 4 \n\nThe mint of the liorsc, according to Fouvcroy and \nYauquelin, contains, \n\nOf Carbonate of lime - \xe2\x80\xa2 11 \n\n\xe2\x80\x94 Carbonate of soda - - 9 \n\n\xe2\x80\x94 J$enzoate of soda - - 24 \n\n\xe2\x80\x94 Muriate of potassa - - 9 \n\n\xe2\x80\x94 Urea - , . - 7 \n\n\xe2\x80\x94 Water and mucilage - - 940 \n\nIn addition to these substances, Mr. Brande found in \nit phosphate of lime. \n\nThe urine of the ass, the camel, the rabbit, and do- \nmestic fowls have been submitted to diflerent experi- \nments, and their constitution iiave been found similar. \nIn tiu^ urine of the rabbit, in addition to most of tlic in- \ngredients above mentioned, Vauquelin detected gelatine; \nand tlie same chemist discovered uric acid in the urine \nof domestic fowls. \n\nHuman urine contains a greater variety of constituents \nthau any other species examined. \n\nUrea, uric acid, and another acid similar to it in na- \nture called rosacic acid, acetic acid, albumen, gelatine, \na n:9inous matter, and various salts arc found in it. \n\n\n\n/\xe2\x96\xa0>,/. /;: \n\n\n\nI\'. L><l\\ \n\n\n\n\n201 \n\nThe human urine differs in composition according to \nthe state of the body, and the nature of the food and \ndrink made use of. In many cases of disease there is a \nmuch larger quantity of gelatine and albumen than usual \nin the urine ; and in diabetes it contains sugar. \n\nIt is probable that the urine of the same animal must \nlikewise differ according to the different nature of the \nfood and drink used ; and this will account for discordan- \ncies in some of the analyses that have been published on \nthe subject. \n\nUrine is very liable to change and to undergo the pu- \ntrefactive process ; and that of carnivorous animals more \nrapidly than that of graminivorous animals. In proper-, \ntion as there is more gelatine and albumen in urine, so \nin proportion does it putrefy Aiore quickly. \n\nThe species of urine that contain most albumen, ge- \nlatine, and urea, are the best as manures ; and all urine \ncontains the essential elements of vegetables in a state \nof solution. \n\nDuring the putrefaction of urine the greatest part of \nthe soluble animal matter that it contains is destroyed ; \nit should consequently be used as fresh as possible ; but \nif not mixed with solid matter, it should be diluted with \nwater, as when pure it contains too large a quantity of \nanimal matter to form a proper fluid nourishment for ab- \nsorption by the roots of plants. \n\nPutrid urine abounds in ammoniacal salts ; and though \nless active than fresh urine, is a very powerful manure. \n\nAccording to a recent analysis published by Eerzcli- \nus, 1000 parts of urine are composed of \n\nWater 933 \n\nUrea - - - - - - 30.1 \n\nUric acid . . . _ \xc2\xb1 \n\nMuriate of ammonia, free lactic ^ \n\nacid, lactate of ammonia andC 17.14 \nanimal matter " \' } \n\nThe remainder different salts, phosphates, sulphates, \nand muriates. \n\nAmongst excremenfitious solid substances used as ma- \nnures, one of the most powerful is the dung of birds that \nfeed on animal food, particularly the dung of sea birds. \nThe guano, v/hich is used to a great extent in Scnth \n\nc c \n\n\n\n202 \n\nAmerica, and which is the manure which fertilizes the \nsterile ])lains of Peru, is a production of this kind. It \nexists abundantly, as we are informed byM. Humbolt, \non the small islands in the South Sea, at Chinche, Ilo; \nIza, and Arica. 50 vessels are laden with it annually \nat Chinche, each of which carries from 1500 to 2000 cu- \nbical feet. It is used as a manure only in very small \nquantities ; and particularly for crops of maize. I made \nsome experiments on specimens of guano sent from South \nAmerica to the Board of Agriculture in 1805. It ap- \npeared as a fine brown powder ; it blackened by heat, \nand gave oft\' strong ammoniacal fumes ; treated with ni- \ntric acid it aflbrded uric acid. In 1806 M. M. Four- \ncroy and Yauquelin published an elaborate analysis of \nguano. They state that i{ contains a fourth part of its \nweight of uric acid, partly saturated with ammonia, and \npartly with potassa ; some phosphoric acid combined \nwith the basis, and likewise with lime. Small quanti- \nties of sulphate and muriate of potassa, a little fatty \nmatter, and some quartzose sand. \n\nIt is easy to explain its fertilizing properties : from \nits composition it might be supposed to be a very pow- \nerful manure. It requires water for the solution of its \nsoluble matter to enable it to produce its full beneficial \neffect on crops. * \n\nThe dung of sea birds has, I believe, never been used \nas a manure in this country; butjt is probable, that even \nthe soil of the small islands on our coast much frequent- \ned by them, would fertilize. Some dung of sea birds \nbrought from a rock on the coast of Merionethshire, \nproduced a powerful but transient effect on grass. It \nwas tried, at my request, by Sir Robert Vaughan at \nNannau. \n\nThe rains in our climate must tend very much to in- \njure this species of manure, where it is exposed to them, \nsoon after its deposition ; but it may probably be found \nin great perfection in caverns or clefts in rocks, haunt- \ned by cormorants and gulls. I examined some recent \ncormorant\'s dung which I found on a rock near Cape Li- \nzard in Cornwall. It had not at all the appearance of the \nguano; was of a grayish white colour; had a very foe- \ntid smell like that of putrid animal matter : when acted \n\n\n\n203 \n\non by quicklime, it gave aljiindauce. of ammonia; treated \nwith nitric acid it yielded uric acid. \n\nJ\\*ight soiU it is well Ichown, is a very powerful ma- \nnure^ and. very liable to decompose. It differs in com- \nposition ; but always abounds in substances composed \nof carbon, hydrogene, azote, and oxygene. From the \nanalysis of Borzelius, it appears that a part of it is al- \nways soluble in water ; and in whatever state it is used, \nwhether recent or fermented, it supplies abundance of \nfood to plants. \n\nThe disagreeable smell of night soil maybe destroy- \ned by mixing it with quicklime ; and if exposed to the \natmosphere in thin layers strewed over with quicklime \nin fine weather, it speedily dries, is easily pulverised, \nand in this state may be used in the same manner as \nrape cake, and delivered into the furrow with the seed. \n\nThe Chinese, who have more practical knowledge of \nthe use and application of manares than any other peo- \nple existing, mix their night soil with one-third of its \nweight of a fat marie, make it into cakes, and dry it by \nexposure to the sun. These cakes, we are informed \nby the French missionaries, have no disagreeable smell, \nand form a common article of commerce of the em- \npire. \n\nThe earth, by its absorbent powers, probably prevents, \nto a certain extent, the action of moisture upon the dung, \nand likewise defends it from the ejttects of air. \n\nAfter night soil, pigeons^ dung comes next in order, \nas to fertilizing power. I digested 100 grains of pi- \ngeons\' dung, in hot water for some hours, and obtained \nfrom it 23 grains of soluble matter; which afforded abun- \ndance of carbonate of ammonia by distillation ; and left \ncarbonaceous matter, saline matter principally common \nsalt, and carbonate of lime as a residuum. Pigeons\' \ndung when moist readily ferments, and after a fermenta- \ntion contains less soluble matter than before : from 100 \nparts of fermented pigeons\' dung, 1 obtained only eight \nparts of soluble matter, which gave proportionally less \ncarbonate of ammonia in distillation than recent pigeons\' \ndung. \n\nIt is evident tliat this manure should be applied as \nnew as possible ; and when dry, it may be employed in \n\n\n\n2U4 \n[|K\' hame niiimiicr us the other miiuures papabie of being \n\nThe soil in woods where great flocks of wood-pigeons \nroost, is often highly impregnated with their dung, and \nit cannot be doubted, would form a valuable manure. \nI have found such soil yield ammonia when distilled \nwith lime. In the winter likewise it usually contains \nabundance of vegetable matter, the remains of decayed \nleaves ; and the dung tends to bring the vegetable mat- \nter into a state of solution. \n\nThe dung of domestic fowls approaches very nearly \nin its nature to pigeons\' dung. Uric acid has been found \nin it. It gives carbonate of ammonia by distillation, and \nimmediately yields soluble matter to water. It is very \nliable to ferment. \n\nThe dung of fowls is employed in common with that \nof pigeons by tanners to bring on a slight degree of pu- \ntrefaction in skins that are to be used for making soft \nleather ; for this purpose the dung is diffused through \nwater. In this state it rapidly undergoes putrefaction, \nand brings on a similar change in the skin. The ex- \ncrements of dogs are employed by the tanner with simi- \nlar eliects. In all cases, the contents of i\\\\^ grainer, as \nthe pit is called in which soft skins are prepared by dung, \nmust form a very useful manure. \n\nRabbits^ dung has never been analysed. It is used \nwith great success a^ a manure by Mr. Fane, who finds \nit profitable to keep rabbits in such a manner as to pre- \nserve their dung. It is laid on as fresh as possible, and \nis found better the less it has fermented. \n\nThe dung of cattle^ oxen^ and cows, has been chemi- \ncally examined by M. M. Einhof and Thaer. They \nfound that it contained matter soluble in water; and that \nit gave in fermentation nearly the same products as ve- \ngetable substances, absorbing oxygene and producing \ncarbonic acid gas. \n\nThe recent dung of sheep, and of deer, afford, when \nlong boiled in water, soluble matters, which equal from \ntwo to three per cent, of their weights I have examin- \ned these soluble substances procured- by solution and \nevaporation ; they contain a very small quantity of mat- \nter analogous to animal mucus ; and are principally com- \n\n\n\n205 \n\nposed of a bitter extract, soluble both in water and in \nalcohol. They give ammoniacal fumes by distillation ; \nand appear very little in composition. \n\nI watered some blades of grass for several successive \ndays with a solution of these extracts ; they evidently be- \ncame greener in consequence, and grew more vigorously \nthangrass in otlier respects, under the same circumstances. \n\nIlie part of the dung of cattle, slieep, and deer, not \nsoluble in water, appears to be mere woody fibre, and \nprecisely analogous to the residuum of those vegetables \nthat form their food after they have been deprived of all \ntheir soluble materials. \n\nThe dung of horses gives a brown fluid, which when \nevaporated, yields a bitter extract, which affords ammo- \nniacal fumes more copiously than that from the dung of \noxen. \n\nIf the pure dung of cattle is to be used as manure, \nlike the other species of dung which have been men- \ntioned, there seems no reason why it should be made to \nferment except in the soil ; or if suffered to ferment, it \nshould be only in a very slight degree. The grass in \nthe neighbourhood of recently voided dung, is always \ncoarse and dark green ; some persons have attributed this \nto a noxious quality in unfermenting dung ; but it seems \nto be rather the result of an excess of food furnislied to \nthe plants. \n\nThe question of the proper mode of the application \nof the dung of horses and cattle, however, properly be- \nlongs to the subject of composite manures^ for it is \nusually mixed in the farm-yard with straw, offal, chafl\', \nand various kind of litter; and itself contains a large \nproportion of fibrous vegetable matter. \n\nA slight incipient fermentation is undoubtedly of use \nin the dunghill ; for by means of it a disposition is \nbrought on in the woody fibre to decay and dissolve, \nwhen it is carried to the land, or ploughed into the soil ; \nand woody fibre is always in great excess in the refuse \nof the farm. \n\nToo great a degree of fermentation is, however, very \nprejudicial to the composite manure in the dunghill ; it \nis better that there should be no fermentation at all be- \nfore the manure is used, than that it should be carried \n\n\n\n206 \n\ntoo far. This must be obvious from what has been al- \nready stated iu this Lecture. The excess of feriaenta- \ntion tends to the destruction and dissipation of the most \nuseful part of the manure ; and the ultimate results of \nthis process are like those of combustion. \n\nIt is a common practice amongst farmers to suffer the \nfarm-yard dung to ferment till the fibrous texture of the \nvegetable matter is entirely broken down ; and till the \nmanure becomes perfectly cold, and so soft as to be easily \ncut by the spade. \n\nIndependent of the general theoretical views unfa- \nvourable to this practice, founded upon the nature and \ncomposition of vegetable substances, there are many ar- \nguments and facts which shew that it is prejudicial to \nthe interests of the farmer. \n\nDuring the violent fermentation wliicli is necessary \nfor reducing farm-yard manure to the state in which it is \ncalled short miicTc^ not only a large quantity of fluid, \nbut likewise of gaseous matter, is lost ; so much so, that \nthe dung is reduced one half, or two thirds in weight ; \nand the principal elastic matter disengaged, in carbonic \nacid with some ammonia ; and both these, if retained \nby the moisture in the soil, as has been stated before, \nare capable of becoming a useful nourishment of plants. \n\nIn October, 1808, I filled a large retort capable of \ncontaining three pints of water, with some hot ferment- \ning manure, consisting principally of the litter and dung \nof cattle ; I adapted a small receiver to the retort, and \nconnected the whole with a mercurial pneumatic appa- \nratus, so as to collect the condensible and elastic fluids \nwhich might rise from tlie dung. The receiver soon \nbecame lined with dew, and drops began in a few hours \nto trickle down the sides of it. Elastic fluid likewise \nwas generated ; in three days thirty-five cubical inches \nhad been formed, which, when analyzed, were found \nto contain twenty-one cubical inches of carbonic acid, \nthe remainder was hydrocarbonate mixed with some \nazote, probably no more than existed in the common \nair iu the receiver. The fluid matter collected in the \nreceiver at tike same time amounted to nearly half an \nounce. It had a saline taste, and a disagreeable smell, \nand contained some acetate and carbonate of ammonia. \n\n\n\n207 \n\nFinding such products given off from fermenting lit- \nter, I introduced the heak of another retort filled with \nsimilar dung very hot at the time, in the soil amongst \nthe roots of some grass in the border of a garden ; in \nless than a week a very distinct effect was produced on \nthe grass ; upon the spot exposed to the influence of the \nmatter disengaged in fermentation, it grew with much \nmore luxuriance than the grass in any other part of the \ngarden. \n\nBesides the dissipation of gaseous matter when fer- \nmentation is pushed to the extreme, there is another dis- \nadvantage in the loss of heat, which, if excited in the \nsoil, is useful in promoting the germination of the seed, \nand in assisting the plant in the first stage of its growth, \nwhen it is most feeble and most liable to disease : and \nthe fermentation of manure in the soil must be particu- \nlarly favourable to the wheat crop in preserving a genial \ntemperature beneath the surface late in autumn, and du- \nring winter. \n\nAgain, it is a general principle in chemistry, that in \nall cases of decomposition, substances combine much \nmore readily at the moment of their disengagement, \nthan after they have been perfectly formed. And in \nfermentation beneath the soil the fluid matter produced \nis applied instantly, even whilst it is warm, to the or- \ngans of the plant, and consequently is more likely to be \nefficient, than in manure that has gone through the pro- \ncess ; and of which all the principles have entered into \nnew combinations. \n\nIn the writings of scientific agriculturists, a great mass \nof facts may be found in favour of the application of \nfarm-yard dung in a recent state. Mr. Young, in the \nEssay on Manures, which I have already quoted, ad- \nduces a number of excellent authorities in support of \nthe plan. Many, who doubted, have been lately con- \nvinced ; and perhaps there is no subject of investigation \nin which there is such a union of theoretical and prac- \ntical evidence. I have myself, within the last ten years, \nwitnessed a number of distinct proofs on the subject. I \nshall content myself with quoting that which ought to \nhave, and which I am sure will have, the greatest weight \namongst agriculturists. Within the last seven years Mr, \n\n\n\n208 \n\nCoke has entirely given up the system formerly adopted \non his farm, of applying fermented dung; and he in- \nforms me, that his crops have been since as good as they \never were, and that his manure goes nearly twice as far. \n\nA great objection against slightly fermented dung is, \nthat weeds spring up more luxuriantly where it is applied. \nIf there are seeds carried out in the dung they certainly \nwill germinate ; but it is seldom that this can be the \ncase to any extent ; and if the land is not cleansed of \nweeds, any kind of manure fermented or unfermented \nwill occasion their rapid growth. If slightly fermented \nfarm-yard dung is used as a top dressing for pastures, \nthe long straws and unfermented vegetable matter re- \nmaining on the surface should be removed as soon as the \ngrass begins to rise vigorously, by raking, and carried \nback to the dunghill : in this case no manure will be \nlost, and the husbandry will be at once clean and eco- \nnomical. \n\nIn cases when farm-yard dung cannot be immediate- \nly applied to crops, the destructive fermentation of it \nshould be prevented as much as possible ; the principles \non which this may be effected have been already allu- \nded to. \n\nThe surface should be defended as much as possible \nfrom the oxygene of the atmosphere ; a compact marie, \nor a tenacious clay, offers the best protection against the \nair ; and before the dung is covered over, or, as it were, \nsealed up, it should be dried as much as possible. If \nthe dung is found at any time to heat strongly, it should \nbe turned over, and cooled by exposure to air. \n\nWatering dunghills is sometimes recommended for \nchecking the progress of fermentation ; but this practice \nis inconsistent with just chemical views. It may cool \nthe dung for a short time ; but moisture, as I have be- \nfore stated, is a principal agent in all processes of de- \ncomposition. Dry fibrous matter will never ferment. \nWater is as necessary as air to the process ; and to sup- \nply it to fermenting dung, is to supply an agent which \nwill hasten its decay. \n\nIn all cases when dung is fermenting, there are sim- \nple tests by which the rapidity of the process, and con- \n2\xc2\xabc\xc2\xabiuently the injury done, may be discovered. \n\n\n\n209 \n\nIf a thermometer plunged into the dung does not rise \nto above 100 degrees of Fahrenheit, there is little dan- \nger of much aeriform matter flying off. If the tempe- \nrature is higher, the dung should be immediately spread \nabroad. \n\nWhen a piece of paper moistened in muriatic acid \nheld over the steams arising from a dunghill gives dense \nfumes, it is a certain test that the decomposition is go- \ning too far, for this indicates that volatile alkali is dis- \nengaged. \n\nWhen dung is to be preserved for any time, the si- \ntuation in which it is kept is of importance. It should, \nif possible, be defended from the sun. To preserve it \nunder sheds would be of great use ; or to make the site \nof a dunghill on the north side of a wall. The floor \non which the dung is heaped, should if possible, be pa- \nved with flat stones ; and there should be a little incli- \nnation from each side towards the centre, in whicli there \nshould be drains connected with a small well, furnished \nwith a pump, by which any fluid matter may be col- \nlected for the use of the land. It too often happens \nthat a (dense mucilaginous and extractive fluid is suffer- \ned to drain away from the dunghill, so as to be entirely \nlost to the farm. \n\nStreet and road dung, and the sweepings of houses, \nmay be all regarded as composite manures : the consti- \ntution of them is necessarily various, as they are deri- \nved from a number of different substances. These ma- \nnures are usually applied in a proper manner, without \nbeing fermented. \n\nSoot, which is principally formed from the combus- \ntion of pit-coal or coal, generally contains likewise sub- \nstances derived from animal matters. This is a very \npowerful manure. It affords ammoniacal salts by dis- \ntillation, and yields a brown extract to hot water, of a \nbitter taste. It likewise contains an-empyreumatic oiL \nIts great basis is charcoal, in a state in which it is ca- \npable of being rendered soluble by the action of oxy- \ngene and water. \n\nThis manure is well fitted to be used in the dry state, \nthrown into the ground with the seed, and requires no \npreparation, \n\nBd \n\n\n\n210 \n\nTill\'- doctrine of the proper application of nmiiurey \nfrom orj:;;iiiis(\',<l wiibstanceH, ollVrs an illnstialiou of an \nimportant part of the, oi(,on(nny of nature, and of the \nliappy order in wliicli it is arranej^cd. \n\n\'^I\'lie di\'Mtli Mtid decay of animal substances lend to \nresolve ori^aniscd forms into cliemical constituents ; and \nthe pernicious ellluvia diseni!;ai;ed in the process seem \nto point out the, pnjpriety of buryinjj; them in the soil, \nwhere they are fitted tu hecom(j the food of vei:;etables. \n\'i\'he fermentation and putrefaction of organised sub- \nstances in the free atmosphere are noxious processes ; \nbeneath the surface of tiie ground they are salutary \noperati(uis. In this case the food of ])lants is prepared \nwhere it < .\'in ]\xc2\xbbe used ; and that which would oiVend the \nsenses and injure the, lu-alth, if exposed, is converted \nby gradual processes into forms of beauty and of use- \nfulness ; the fo\'tid gas is rendered a constituent of the \naroma of the ilower, and what might be poison, becomes \nnourishment to animals and to man. \n\n\n\nOn Munurp.8 of mineral Orii^in, or fosmln ManmuiH ; \ntheir Preparation, and the Mwnncr in which thai/ \nAct. Of Lime in ita dijf\'erent State a ; Opej\'ution of \nLime as a Manure and, a Cement ; different Comt)i- \nnations of Lime. Of Gyfisum. ; Ideas respectini:; its \nUse. Of other JS\'eiitro- saline domponnds, emjitoijed, \nus Manures. Of Alkalies and at k aline Salts; (f \nCommjm Salt. \n\nJL HE whole tenor oi\' fJie precediui; lieclnrcH shew.s^ \nthat a \xc2\xa3;reat variety of suhstaiices (;oiitriljute,.s to the \ngrowth of plants, and supplies the materials of their \nriourislimcnt. The conversion of matter that has he- \nlonged to living structures into organised forms is a pro- \ncess that can he easily understoorl ; hut it is more dif- \niicult to foih>w those operations hy which earthy and \nsaline matters are consolidated in the iihre of plants, \nand hy which they are made- snhservient to their func- \ntions. Some inquirers adopting that suhlirnc. generali- \nzation of the ancient philosophers, that matter is the \nsame in essence, and that the dillcntnt suhstances con- \nsidered as e.lements hy chemists, are merely diil\'erent \narrangements of the same indeslruf^tihie particles, have \nendeavoured to prove, that all the vari(5(.ies of the prin- \ncijdes found in plants, may he formed from the suhstan- \nces in the atmosphere; and that vegcitahh*. life is a pro- \ncess in which hodies that the analytical philosopher is \nunahle to change or to form, are ccmstantly com[\xc2\xbbosed \nand decomposed. These opinions have not heen ad- \nvanced merely as hypotheses; attempts have heen made \nto supj)ort them i>y experiments. M. Hchra-dar and \nMr. J5raconnet, from a series of distinct investigations, \nhave arrived at the same conclusions. They stale that \ndifl\'erent seeds sown in fine sand, sulphur, and metallic \noxides, and supplied only with atmospherical air and \n\xe2\x96\xa0water, produced ln\'.althy plants, which hy analysis \n\n\n\n*i I \'i \n\nyielded various earthy and saline matters, Avliich eiiliei* \nwere not contained in the seeds, or the material in whicli \nthey grew ; or which were contained only in much \nsmaller quantities in the seeds : and hence they conclude \nthat they must have ])een formed from air or water, in \nconsequence of the agencies of the living organs of the \nplant. \n\nThe researches of these two gentlemen were conduct- \ned with much ingenuity and address ; but there were cir- \ncumstances which interfered with their results, which \nthey could not have known, as at the time their labours \nwere published they had not been investigated. \n\nI have found that common distilled water is iar from, \nbeing free from saline impregnations. In analysing it \nby Voltaic electricity, I procured from it alkalies and \nearths ; and many of the combinations of metals with \nchlorine are extremely volatile substances. When dis- \ntilled water is supplied in an unlimited manner to plants, \nit may furnish to them a number of difterent substances, \nwhich though in quantities scarcely perceptible in the \nwater, may accumulate in the plant, which probably per- \nspires only absolutely pure water. \n\nIn 1801, I made an experiment on the growth of oats, \nsupplied with a limited quantity of distilled water in a \nsoil composed of pure carbonate of lime. The soil and \nthe water were placed in a vessel of iron, which was in- \ncluded in a large jar, connected with the free atmosphere \nby a tube, so curved as to prevent the possibility of any \ndust, or fluid, or solid matter from entering into the jar. \nMy object was to ascertain whether any siliceous earth \nwould be formed in the process of Vegetation ; but the \noats grew very feebly, and began to be yellow before \nany flowers formed : the entire plants were burnt, and \ntheir ashes compared with those from an equal number \nof grains of oats. Less silicious earth was given by the \nplants than by the grains ; but their ashes yielded much \nmore carbonate of lime. That there was less siliceous \nearth I attribute to the circumstance of the husk of the \noat being thrown oft* in germination ; and this is the part \nwhich most abounds in silica. Healthy green oats taken \nfrom a growing crop, in a field of which the soil was a \nfine sand, yielded siliceous earth in a much gieater pro- \n\n\n\n\'il3 \n\nportion than au equal weight of the corn artificially \nraised. \n\nThe general results of this experiment are very much \nopposed to the idea of the composition of the earths, by \nplants, from any of the elements found in the atmo- \nsphere, or in water ; and there are other facts contra- \ndictory to the idea. Jacquin states that the ashes of glass \nwort {Salsola soda,) when it grows in inland situations, \nafford the vegetable alkali ; when it grows on the sea v \nshore, where compounds which afford the fossile or ma- \nrine alkali are more abundant, it yields that substance. \nDu Hamel found, that plants which usually grow on the \nsea shore, made small progress when planted in soils \ncontaining little common salt. The sunflower, when \ngrowing in lands containing no nitre, does not afford \nthat substance ; though when watered by a solution of \nnitre, it yields nitre abundantly. The tables of de Saus- \nsure, referred to in the Third Lecture, shew that the \nashes of plants are similar in constitution to the soils in \nwhich they have vegetated. \n\nDe Saussure made plants grow in solutions of differ- \nent salts, and he ascertained, that in all cases, certain \nportions of the salts were absorbed by the plant, and \nfound unaltered in their organs. \n\nEven animals do not appear to possess the power of \nforming the alkaline and earthy substances. Dr. For- \ndyce found, that when canary birds, at the time they \nwere laying eggs, were deprived of access to carbonate \nof lime, their eggs had soft shells ; and if there is any \nprocess for which nature ma^be conceived most likely \nto supply resources of this kind, it is that connected with \nthe reproduction of the species. \n\nAs the evidence on the subject now stands, it seems \nfair to conclude, that the different earths and saline sub- \nstances found in the organs of plants are supplied by \nthe soils in which they grow ; and in no cases composed \nby new arrangements of the elements in air or water. \nWhat may be our ultimate view of the laws of chemis- \ntry, or how far our ideas of elementary principles may \nbe simplified, it is impossible to say. We can only rea- \nson from facts. We cannot imitate the powers of com- \nposition belonging to vegetable structures ; but at least \n\n\n\nwe can understand them : and as far as our researches \nhave gone, it appears, that in vegetation coin|)ound \nforms are uniformly produced from simpler ones ; and \nthe elements in the soil, the atmosphere, and the earth \nabsorbed and made parts of beautiful and diversified \nstructures. \n\nThe views which have been just developed lead to \ncorrect ideas of the operation of these manures which \nare not necessarily the result of decayed organised bo- \ndies, and which are not composed of different propor- \ntions of carbon, hydrogene, oxygene, and azote. \xe2\x80\x94 They \nmust produce their effect, either by becoming a constitu- \nent part of the plant, or by acting upon its more essen- \ntial food, so as to render it more fitted for the purposes \nof vegetable life. \n\nThe only substances which can with propriety be \ncalled fossile manures, and which are found unmixed \nwith the remains of any organised beings, are certain \nalkaline earths or alkalies, and their combinations. \n\nThe only alkaline earths which have been hitherto \napplied in this way, are lime and magnesia. Potassa \nand soda, the two fixed alkalies, are both used in certain \nof their chemical compounds. I shall state in succession \nsuch facts as have come to my knowledge respecting \neach of these bodies in their applications to the purposes \nof agriculture ; but I shall enlarge most upon the sub- \nject of lime ; and if I should enter into some details \nwhich may be tedious and minute, I trust, my excuse \nwill be found in the importance of the inquiry ; and it \nis one which has been greatly elucidated by late disco- \nveries. \n\nThe most common form in which lime is found on \nthe surface of the earth, is in a state of combination \nwith carbonic acid or fixed air. If a piece of lime- \nstone, or chalk, be thrown into a fluid acid, there will \nbe an effervescence. This is owing to the escape of \nthe carbonic acid gas. The lime becomes dissolved in \nthe liquor. \n\nWhen limestone is strongly heated, the carbonic acid \ngas is expelled, and then nothing remains but the pure \nalkaline earth ; in this case there is a loss of weight ; \nand if the fire has been very high, it approaches to one- \n\n\n\n:ii5 \n\nhalf the weight of the stone ; but iii comuiou cases, iime- \nstones, if well dried before burning, do not lose much \nmore than from 35 to 40 per cent., or from seven to eight \nparts out of twenty. \n\nI mentioned, in discussing the agencies of the atmo- \nsphere upon vegetables, in the beginning of the Fifth \nLecture, that air always contains carbonic acid gas, and \nthat lime is precipitated from water by this substance. \nWhen burnt lime is exposed to the atmosphere, in a cer- \ntain time it becomes mild, and is the same substance as \nthat precipitated from lime water ; it is combined with \ncarbonic acid gas. Quicklime, when fi^\'t made, is caustic \nand burning to the tongue, renders vegetable blues \ngreen, and is soluble in water; but when combined with \ncarbonic acid it looses all these properties, its solubili- \nty and its taste : it regains its power of effervescing, and \nbecomes the same chemical substance as chalk, or lime- \nstone. \n\nVery few limestones, or chalks, consist entirely of \nlime and carbonic acid. The statuary marbles, or cer- \ntain of the rhomboidal spars, are almost the only pure \nspecies ; and the different properties of limestones, both \nas manures and cements, depend upon the nature of the \ningi\'edients mixed in the limestone ; for the true calca- \nreous clement, the carbonate of lime, is uniformly the \nsame in nature, properties, and effects, and consists of \none proportion of carbonic acid 41.4, and one of lime \n55. \n\nWhen a limestone does not copiously effervesce in \nacids, and is sufficiently hard to scratch glass, it contains \nsiliceous, and probably aluminous earth. When it is \ndeep brown, or red, or strongly coloured of any of the \nshades of brown or yellow, it contains oxide of iron. \nWhen it is not sufficiently hard to scratch glass, but ef- \nfervesces slowly, and makes the acid in which it effer- \nvesces milky, it contains magnesia. And when it is black, \nand emits a foetid smell if rubbed, it contains coaly or \nbituminous matter. \n\nThe analysis of limestones is not a difficult matter ; \nand the proportions of their constituent parts may be ea- \nsily ascertained, by the processes described in the Lec- \nture on the Analysis of Soils ; and usually with suffi- \n\n\n\n216 \n\ncient accuracy for all the purposes of the farmer, by the \nfifth process. \n\nBefore any opinion can be formed of the manner in \nwhich the different ingredients in limestone modify their \nproperties, it will be necessary to consider the operation \nof the pure calcareous element as a manure, and as a \ncement. \n\nQuicklime in its pure state, whether in powder, or \ndissolved in water, is injurious to plants. \xe2\x80\x94 I have in se- \nveral instances killed grass by watering it with lime wa- \nter. \xe2\x80\x94 But lime, in its state of combination with carbonic \nacid, as is evident from the analyses given in the Fourth \nLecture, is a useful ingredient in soils. Calcareous \nearth is found in the ashes of the greater number of \nplants ; and exposed to the air, lime cannot long conti- \nnue caustic, for the reasons that were just now assign- \ned, but soon becomes united to carbonic acid. \n\nWhen newly burnt lime is exposed to air, it soon falls \ninto powder ; in this case it is called slacked lime ; and \nthe same effect is immediately produced by throwing wa- \nter upon it, when it heats violently, and the water dis- \nappears. \n\nSlacked lime is merely a combination of lime, with \nabout one third of its weight of water ; i. e. fifty-five \nparts of lime absorb seventeen parts of water ; and in \nthis case it is composed of a definite proportion of wa- \nter, and is called by chemists hydrate of lime ; and when \nhydrate of lime becomes carbonate of lime by long ex- \nposure to air, the water is expelled, and the carbonic \nacid gas takes its place. \n\nWhen lime, whether freshly burnt or slacked, is mix- \ned with any moist fibrous vegetable matter, there is a \nstrong action between the lime and the vegetable mat- \nter, and they form a kind of compost together of which \na part is usually soluble in water. \n\nBy this kind of operation, lime renders matter which \nwas before comparatively inert, nutritive ; and as char- \ncoal and oxygene abound in all vegetable matters, it \nbecomes at the same time converted into carbonate of \nlime. \n\nMild lime, powdered limestone, marles, or chalks, \nhave no action of this kind upon vegetable matter ; by \n\n\n\n217 \n\ntheir action they prevent the too rapid decomposition of \nsubstances already dissolved ; but they have no tenden- \ncy to form soluble matters. \n\nIt is obvious from these circumstances, that the ope- \nration of quicklime, and marie or chalk, depends upon \nprinciples altogether different. \xe2\x80\x94 Quicklime in being ap- \nplied to land, tends to bring any hard vegetable matter \nthat it contains into a state of more rapid decomposition \nand solution, so as to render it a proper food for plants. \n\xe2\x80\x94 Chalk and marie, or carbonate of lime, will only im- \nprove the texture of the soil, or its relation to absorp- \ntion ; it acts merely as one of its earthy ingredients.\xe2\x80\x94- \nQuicklime, when it becomes mild, operates in the same \nmanner as chalk ; but in the act of becoming mild, it \nprepares soluble out of insoluble matter. \n\nli is upon this circumstance that the operation of lime \nin the preparation of wheat crops depends ; and its ef- \nficacy in fertilizing peats, and in bringing into a state of \ncultivation all soils abounding in hard roots or dry fibres, \nor inert vegetable matter. \n\nThe solution of the question whether quicklime ought \nto be applied to a soil, depends upon the quantity of in- \nert vegetable matter that it contains. The solution of \nthe question, whether marie, mild lime, or powdered \nlimestone, ought to be applied, depends upon the quan- \ntity of calcareous matter already in the soil. All soils \nare improved by mild lime, and ultimately by quicklime, \nwhich do not effervesce with acids ; and sands more than \nclays. \n\nWhen a soil deficient in calcareous matter contains \nmuch soluble vegetable manure, the application of quick- \nlime should always be avoided, as it either tends to de- \ncompose the soluble matters by uniting to their carbon \nand oxygeue so as to become mild lime, or it combines \nwithjthe soluble matters, and forms compounds having \nless attraction for water than the pure vegetable sub- \nstance. \n\nThe case is the same with respect to most animal \nmanures ; but the operation of the lime is different in \ndifferent cases, and depends upon the nature of the ani- \nmal matter. Lime forms a kind of insoluble soap with \noily matters, and then gradually decomposes them by \n\nE e \n\n\n\n3(8 \n\nseparating from them oxygene and carbon. It combines \nlikewise with the animal acids, and probably assists \ntheir decomposition by abstracting carbonaceous matter \nfrom them combined with oxy\xc2\xa3;ene ; and, consequently, \nit must render them less nutritive. It tends to diminish \nlikewise the nutritive powers of albumen from the same \ncauses ; and always destroys, to a certain extent, the \nefficacy of animal manures, either by combining with \ncertain of their elements, or by giving to them new ar- \nrangements. Lime should never be applied with ani- \nmal manures, unless they are too rich, or for the pur- \npose of preventing noxious effluvia, as in certain cases \nmentioned in the last Lecture. It is injurious when mix- \ned with any common dung, and tends to render the ex- \ntractive matter insoluble. \n\nI made an experiment on this subject: I mixed a \nquantity of brown soluble extract, which was procured \nfrom sheeps\' dung with five times its weight of quick- \nlime. I then moistened them with water ; the mixture \nheated very much ; it was suft\'ered to remain for four- \nteen hours, and was then acted on by six or seven times \nits bulk of pure water : the water, after being passed \nthrough a filtre, was evaporated to dryness ; the solid \nmatter obtained was scarcely coloured, and was lime \nmixed with a little saline matter. \n\nIn those cases in which fermentation is useful to pro- \nduce nutriment from vegetable substances, lime is always \nefficacious. I mixed some moist tanner\'s spent bark with \none-fifth of its weight of quicklime, and suffered them \nto remain together in a close vessel for three months ; \nthe lime had become coloured, and was effervescent : \nwhen water was boiled upon the mixture, it gained a \ntint of fawn colour, and by evaporation furnished a fawn- \ncoloured powder, which must have consisted of lime \nunited to vegetable matter, for it burnt when strongly \nheated, and left a residuum of mild lime. \n\nThe limestones containing alumina and silica are less \nfitted for the purposes of manure than pure limestones ; \nbut the lime formed from them has no noxious quality. \nSuch stones are less efficacious, merely because they fur- \nnish a smaller quantity of quicklime. \n\nI mentioned bituminous limestones. There is very \n\n\n\n2tt> \n\nseldom any considerable portion of coaly matter in these \nstones ; never as much as five parts in 100 ; but such \nlimestones make very good lime. The carbonaceous \nmatter can do no injury to the Land, and may^ under \ncertain circumstances, become a food of the plant, as is \nevident from what was stated in the last Lecture. \n\nThe subject of the application of the magnesian lime- \nstone is one of great interest. \n\nIt had been long known to farmers in the neighbour- \nhood of Doncaster, that lime made from a certain lime- \nstone applied to the land, often injured tlie crops con- \nsiderably, as I mentioned in the introductory Lecture. \nMr. Tennant, in making a series of experiments upon \nthis peculiar calcareous substance, found that it contain- \ned magnesia ; and on mixing some calcined magnesia \nwith soil, in which he sowed different seeds, he found \nthat they either died, or vegetated in a very imperfect \nmanner, and the plants were never healthy. And with \ngreat justice and ingenuity he referred the bad effects \nof the peculiar limestone to the magnesian earth it con- \ntains. \n\nIn making some inquiries concerning this subject, I \nfound that there were cases in which this magnesian \nlimestone was used with good effect. \n\nAmongst some specimens of limestone which Lord \nSomerville put into my hands, two marked as peculiar- \nly good proved to be magnesian limestones. And lime \nmade from the JBreedon limestone is used in Leicester- \nshire, where it is called hot lime ; and 1 have been in- \nformed by farmers in the neighbourhood of the quarry, \nthat they employ it advantageously in small quantities, \nseldom more than 25 or 30 bushels to the acre. And \nthat they find it may be used with good effect in larger \nquantities, upon rich land. \n\nA minute chemical consideration of this question will \nlead to its solution. \n\nMagnesia has a much weaker attraction for carbonic \nacid than lime, and will remain in the state of caustic \nor calcined magnesia for many months, though exposed \nto the air. And as long as any caustic lime remains, \nthe magnesia cannot be combined with carbonic acid, \nfor lime instantly attracts carbonic acid from magnesia. \n\n\n\n220 \n\nWlieu a magnesian limestone, is burnt, the magnesia \nis deprived of carbonic acid much sooner than the lime ; \nand if there is not much vegetable or animal matter in \nthe soil to supply by its decomposition carbonic acid, \nthe magnesia will remain for a long time in the caustic \nstate ; and in this state acts as a poison to certain vege- \ntables. And that more magnesian lime may be used \nupon rich soils, seems to be owing to the circumstance^ \nthat the decomposition of the manure in them supplies \ncarbonic acid. And magnesia in its mild state, i. e. \nfully combined with carbonic acid, seems to be always \na useful constituent of soils. I have thrown carbon- \nate of magnesia (procured by boiling the solution of mag- \nnesia in super-carbonate of potassa) upon grass, and \nupon growing ^\\\'heat and barley, so as to render the sur- \nface white; but the vegetation was not injured in the \nslightest degree. And one of the most fertile parts of \nCornwall, the Lizard, is a district in which the soil con- \ntains mild magnesian earth. \n\nThe Lizard Downs bear a short and green grass, \nwhich feeds sheep producing excellent mutton ; and the \ncultivated parts are amongst the best corn lands in the \ncounty. \n\nThjrt the theory which I have ventured to give of the \noperation of magnesian lime is not unfounded, is shewn \nby an experiment which 1 made expressly for the pur- \npose of determining the true nature of the operation of \nthis substance. I took four portions of the same soil : \nwith one 1 mixed ^V of its weight of caustic magnesia, \nwith another I mixed the same quantity of magnesia \nand a proportion of a fat decomposing peat equal to one- \nfourth of the weight of the soil. One portion of soil re- \nmained in its natural state ; and another was mixed with \npeat without magnesia. The mixtures were made in De- \ncember 1806 ; and in April 1807, barley was sown ia \nall of them. It grew very well in the pure soil, but bet- \nter in the soil containing the magnesia and peat ; and \nnearly as well in the soil containing peat alone : but in \nthe soil containing the magnesia alone, it rose very \nfeeble, and looked yellow and sickly. \n\n1 repeated this experiment in the summer of 1810 with \nsimilar results ; and I found that the magnesia in the \n\n\n\n221 \n\nsoil mixed with peat became strongly eftervescent; \nwhilst the portion in the unmixed soil gave carbonic \nacid in much smaller quantities. In the one case the \nmagnesia had assisted in the formation of a manure, \nand had become mild ; in the other case it had acted as \na poison. \n\nIt is obvious, from what has been said, that lime from \nthe magnesian limestone may be applied in large quan- \ntities to peats ; and that where lands have been injured \nby the application of too large a quantity of magnesian \nlime, peat will be a proper and efficient remedy. \n\nI mentioned that magnesian limestones effervesced \nlittle when plunged into an acid. A simple test of mag- \nnesia in a limestone is this circumstance, and its render- \ning diluted nitric acid or aqua fortis milky. \n\nFrom the analysis of Mr. Tennant, it appears that \nthe magnesian limestones contain from \n\n20.3 to 22.5 magnesia. \n\' 29.5 to 31.7 lime. \n47.2 carbonic acid. \n0.8 clay and oxide of iron. \n\nMagnesian limestones are usually coloured brown or \npale yellow. They are found in Somersetshire, Lei- \ncestershire, Derbyshire, Shropshire, Durham, and York- \nshire. I have never met with any in other counties in \nEngland ; but they abound in many parts of Ireland, \nparticularly near Belfast. \n\nThe use of lime as a cement, is not a proper subject \nfor extensive discussion in a course of Lectures on the \nchemistry of agriculture ; yet as the theory of the opera- \ntion of lime in this way is not fully stated in any elemen- \ntary book that I have perused, I shall say a very few \nw^ords on the applications of this part of chemical know- \nledge. \n\nThere are two modes in which lime acts as a cement ; \nin its combination with water, and in its combination \nwith carbonic acid. \n\nThe hydrate of lime has been already mentioned. \nWhen quicklime is rapidly made into a paste with wa- \nter, it soon loses its softness, and the water and the lime \n\n\n\n222 \n\nform togcllier a solid colicieiit mass, winch consists, us \nhas been staled before, of 17 parts of water to 55 \nparts of lime. When hydrate of lime whilst it is con- \nsolidating, is mixed with red oxide of iron, alumina, \nor silica, tlie mixture becomes harder and more cohe- \nrent than when lime alone is used : and it appears that \nthis is owing to a certain degree of chemical attraction \nbetween hydrate of lime and these bodies ; and tfiey \nrender it less liable to decompose by the action of the \ncarbonic acid in the air, and less soluble in water. \n\nThe basis of all cements that are used for works \nwhich are to be covered with water must be formed from \nhydrate of lime ; and the lime made from impure lime- \nstones answers this purpose very well. Puzzolana is \ncomposed principally of silica, alumina, and oxide of \niron ; and it is used mixed with lime to form cements \nintended to be employed under water. Mr. Smeaton, \nin the construction of the Eddystone lighthouse, used a \ncement composed of equal parts by weight of slacked \nlime and puzzolana. Puzzolana is a decomposed lava. \nTarras, which was formerly imported in considerable \nquantities from Holland, is a mere decomposed basalt : \ntwo parts of slacked lime and one part of tarras forms \nthe principal part of the mortar used in the great dykes \nof Holland. Substances which will answer all the \nends of puzzolana and tarras are abundant in the Bri- \ntish islands. An excellent red tarras may be procured \nin any quantities from the Giant\'s Causeway, in the \nnorth of Ireland : and decomposing basalt is abundant \nin many parts of Scotland, and in the northern districts \nof England in which coal is found. \n\nParker\'s cement, and cements of the same kind made \nat the alum works of Lord Dundas and Lord Mulgrave, \nare mixtures of calcined ferruginous, siliceous, and alu^ \nminous matter, with hydrate of lime. \n\nThe cements which act by combining with carbonic \nacid, or the common mortars, are made by mixing to- \ngether slacked lime and sand. These mortars, at first \nsolidify as hydrates, and are slowly converted into car- \nbonate of lime by the action of the carbonic acid of the \nair. Mr. Tennant found that a mortar of this kind in \n4hree years and a quarter Iiad regained 63 per cent, of \n\n\n\nthe quantity of carbonic acid gas which constitutes the \ndefinite proportion in carbonate of lime. The rubbish \nof mortar from houses owes its power to benefit lands \nprincipally to the carbonate of lime it contains, and the \nsand in it ; and its state of cohesion renders it particu- \nlarly fitted to improve clayey soils. \n\nThe hardness of the mortar in very old buildings de- \npends upon the perfect conversion of all its parts into \ncarbonate of lime. The purest limestones are tlie best \nadapted for making this kind of mortar ; the magnesian \nlimestones make excellent water cements, but act with \ntoo little energy upon carbonic acid gas to make good \ncommon mortar. \n\nThe Romans according to Pliny, made their best \nmortar a year before it was used : so that it was par- \ntially combined with carbonic acid gas before it was \nemployed. \n\nIn burning lime there are some particular precautions \nrequired for the different kinds of limestones. In ge- \nneral, one bushel of coal is sufficient to make four or \nfive bushels of lime. The magnesian limestone re- \nquires less fuel than the common limestone. In all \ncases in which a limestone containing much aluminous \nor siliceous earth is burnt, great care should be taken \nto prevent the fire from becoming too intense ; for such \nlime easily vitrifies, in consequence of the affinity of \nlime for silica and alumina. And as in some places \nthere are no other limestones than such as contain other \neartlis, it is important to attend to this circumstance. \nA moderately good lime may be made at a low red \nheat ; but it will melt into a glass at a white heat. In \nlimekilns for burning such lime, there should be always \na damper. \n\nIn general, when limestones are not magnesian their \npurity will be indicated by their loss of weight in burn- \ning ; the more they lose, the larger is the quantity of \ncalcareous matter they contain. The magnesian lime- \nstones contain more carbonic acid than the common lime- \nstones ; and I have found all of them lose more than \nhalf their weight by calcination. \n\nBesides being used in the forms of lime and carbon- \n?ite of lime, calcareous matter is applied for the pur- \nposes of agriculture iu other combinations. One of thesis \n\n\n\n224 \n\nbodies is gyijsum or sulphate of lime. This substance \nconsists of sulphuric acid (the same body that exists \ncombined with water in oil of vitriol) and lime ; and \nwhen dry it is composed of 55 parts of lime and 75 \nparts of sulphuric acid. Common gypsum or selenite, \nsuch as that found at Shotover Hill, near Oxford, con- \ntains, besides sulphuric acid and lime, a considerable \nquantity of water ; and its composition may be thus ex- \npressed : \n\nSulphuric acid, one proportion - 75 \nLime, one proportion - - 55 \n\nWater, two proportions - - 34 \n\nThe nature of gypsum is easily demonstrated ; if oil \nof vitriol be added to quicklime, there is a violent heat \nproduced ; when the mixture is ignited, water is given \noff, and gypsum alone is the result, if the acid has been \nused in sufficient quantity; and gypsum mixed with \nquicklime, if the quantity has been deficient. Gypsum, \nfree from water, is sometimes found in nature, when it \nis called anhydrous solenite. It is distinguished from \ncommon gypsum by giving off no water when heated. \n\nWhen gypsum, free from water, or deprived of wa- \nter by heat, is made into a paste with water, it rapidly \nsets by combining with that fluid. Plaster of Paris is \npowdered dry gypsum, and its property as a cement, \nand in its use in making casts, depends upon its solidi- \nfying a certain quantity of water, and making with it a \ncoherent mass. Gypsum is soluble in about 500 times \nits weight of cold water, and is more soluble in hot wa- \nter ; so that when water has been boiled in contact with \ngypsum, crystals of this substance are deposited as the \nwater cools. Gypsum is easily distinguished by its \nproperties of affording precipitates to solutions of oxa- \nlates and of barytic salts. \n\nGreat difference of opinion has prevailed amongst \nagriculturists with respect to the uses of gypsum. It \nhas been advantageously used in Kent, and various tes- \ntimonies in favour of its efficacy have been laid before \nthe Board of Agriculture of Mr. Smith. In America \nit is imployed with signal success ; but in most coun- \nties of England it has failed, though tried in various \nways, and upon different crops. \n\nVery discordant notions have been formed as to the \n\n\n\n225 \n\nmode of operation of gypsum. It has been supposed \nby some persons to act by its power of attracting mois- \nture from the air ; but this agency must be compara- \ntively insignificant. When combined with water, it re- \ntains that fluid too powerfully to yield it to the roots \nof the plant, and its adhesive attraction for moisture is \ninconsiderable ; the small quantity in which it is used \nlikewise is a circumstance hostile to this idea. \n\nIt has been said that gypsum assists the putrefaction \nof animal substances, and the decomposition of manure. \nI have tried some experiments on this subject which are \ncontradictory to the notion. I mixed some minced veal \nwith about one-one hundredth part of its weight of gyp- \nsum, and exposed some veal without gypsum under the \nsame circumstances ; there was no diff\'erence in the time \nin which they began to putrify, and the process seem- \ned to me most rapid in the case in which there was no \ngypsum present. I made other similar mixtures, em- \nploying in some cases larger, and in some cases smaller \nquantities of gypsum ; and I used pigeons\' dung in one \ninstance instead of flesh, and with precisely similar re- \nsults, it certainly in no case increased the rapidity of \nputrefaction. \n\nThough it is not generally known, yet a series of ex- \nperiments has been carried on for a great length of time \nin this country upon the operation of gypsum as a ma- \nnure. The Berkshire and the Wiltshire peat-ashes con- \ntain a considerable portion of this substance. In the \nNewbury peat-ashes I have found from one-fourth to \none-third of gypsum, and a larger quantity in some \npeat-ashes from the neighbourhood of Stockbridge : the \nother constituents of these ashes are calcareous, alumi- \nnous, and siliceous earth, with variable quantities of \nsulphate of potassa, a little common salt and sometimes \noxide of iron. The red ashes contain most of this last \nsubstance. \n\nThese peat-ashes are used as a top dressing for cul- \ntivated grasses, particularly sainfoin and clover. In ex- \namining the ashes of sainfoin, clover, and rye grass, I \nfound that they afforded considerable quantities of gyp- \nsum ; and this substance, probably, is intimately com- \nbined as a ncccssai-v part of their woody fibre. If this \n\nF f \n\n\n\n326 \n\nl<b allowed, it is easy to explain tlie reason why it ope- \nrates in such small quantities; for the whole of a clover \ncrop, or saiufoiu crop, on an acre, according to my es- \ntimation, would aiford hy incineration only three or four \nItusliels of gypsum. In examining the soil in a field \nnear Newbury, which w^as taken from below a foot-path \nnear the gate, where gypsum could not have been arti- \nficially furnished, I could not detect any of this substance \nin it; and at the very time I collected the soil, the peat- \nashes were applied to the clover in the field. The rea- \nson why gypsum is not generally efficacious, is probably \nbecause most cultivated soils contain it in sufficient \nquantities for the use of the grasses. In the common \ncourse of cultivation gypsum is furnished in the manure ; \nfor it is contained in stable dung, and in the dung of all \ncattle fed on grass ; and it is not taken up in corn crops, \nor crops of peas and beans, and in very small quanti- \nties in turnip crops; but where lands are exclusive- \nly devoted to pasturage and hay, it will be continually \nconsumed. I have examined four different soils culti- \nvated by a series of common courses of crops, for gyp- \nsum. One was a light sand from Norfolk ; another a \n\xe2\x80\xa2clay, bearing a good wheat, from Middlesex ; the third \na sand, from Sussex ; the fourth a clay, from Essex. I \nfound gypsum in all of them ; and in the Middlesex soil \nit amounted nearly to one per cent. Lord Dundas in- \nforms me, that having tried gypsum without any benefit \non two of his estates in Yorkshire, he was induced to \nhave the soil examined for gypsum, according to the \nprocess described in the Fourth Lecture, and this sub- \nstance was found in both the soils. \n\nShould these statements be confirmed by future inqui- \nries, a practical inference of some value may be derived \nfrom them. It is possible that lands which have ceased \nto bear good crops of clover, or artificial grasses, may \nbe restored by being manured with gypsum. I have \nmentioned that this substance is found in Oxfordshire ; \nit is likewise abundant in many other parts of England; \nin Gloucestershire, Somersetshire, Derbyshire, York- \nshire, &c. and requires only pulverization for its prepa- \nration. \n\nSome very interesting documents upon the use of sul- \n\n\n\nlihaie of ii\'oii or green vilriol, wliich is a salt producid \nfrom peat in Bedfordshire, have been laid belore tiie \nBoard by Dr. Pearson; and I have witnessed the fer- \ntilizing effects of a fcrrnginous water used forirrijijatini;; \na grass meadow made by the Duke of Manchester at \nPriestly Bog, near Woburn, an account of tiie produce \nof which has been published by the Board of Agricul- \nture. 1 have no doubt that the peat salt and the vi- \ntriolic water acted chiefly l)y pro(hicing gypsum. \n\nThe soils on which both are eflicacious are calcare- \nous; and sulphate of iron is decomposed l)ythe carbon- \nate of lime in sucli soils. The sulpliatc of iron con- \nsists of sulphuric acid and oxide of iron, and is an acid \nand a very -soluble salt; when a solution of it is mixed \nwith carbonate of lime, the sulphuric acid quits tlje ox- \nide of iron to unite to the lime, and the compounds pro- \nduced are insipid and comparatively insoluble. \n\nI collected some of the decomposition from the ferrugi- \nnous water on the soil in Priestley meadow. I found \nit consisted of gypsum, carbonate of iron, and insoluble \nsulphate of iron. The principal grasses in Priestley \nmeadow are, meadow fox-tail, cock\'s foot, meadow fes- \ncue, fiorin, and sweet scented vernal grass. I have ex- \namined the ashes of three of these grasses, meadow fox- \ntail, cock\'s foot, and fiorin. They contained a consi- \nderable proportion of gypsum. \n\nVitriolic impregnations in soils where there is no cal- \ncareous matter, as in a soil from Lincolnshire, to which \nI referred in the Fourth Lecture, are injurious; but it \nis probably in consequence of their supplying an excess \nof ferruginous matter to the sap. Oxide of iron in small \nquantities forms a useful part of soils ; and, as is evi- \ndent from the details in the Third Lecture, it is found \nin the ashes of plants, and probably is hurtful only in \nits acid combinations. \n\nI have just mentioned certain peats, the ashes of which \nafford gypsum; but it must not be inferred from this \nthat all peats agree with them. I have examined vari- \nous peat-ashes from Scotland, Ireland, Wales, and the \nnorthern and western parts of England, ^vhich contain- \ned no quantity that could be useful: and these ashes \n\n\n\n,i2b \n\naboiuitled in silicious, aluminous earths, and oxide of \niron. \n\nLord Charleville found in some peat-ashes from Ire- \nland sulphate of potassa, i. e. the sulphuric acid combi- \nned with potassa. \n\nVitriolic matter is usually formed in peats ; and if the \nsoil or substratum is calcareous, the ultimate result is \nthe production of ii;ypsum. In general, when a recent \npeat-ash emits a strong smell resembling that of rotten \neggs when acted upon by vinegar, it will furnish gyp- \nsum. \n\nPhosphate of lime is a combination of phosphoric acid \nand lime, one proportion of each. It is a compound in- \nsoluble in pure water, but soluble in water containing \nany acid matter. It forms the greatest part of calcined \nbones. It exists in most excrementitious substances, \nand is found both in the straw and grain of wheat, bar- \nley, oats, and rye, and likewise in beans, peas and \ntares. It exists in some places in these islands native, \nbut only in very small quantities. Phosphate of lime is \ngenerally conveyed to the land in the composition of \nother manure, and it is probably necessary to corn crops \nand other white crops. \n\nBone ashes ground to powder will probably be found \nuseful on arable lands containing much vegetable mat- \nter, and may perhaps enable soft peats to produce \nwheat ; but the powdered l)one in an uncalcined state \nis much to be preferred in all cases when it can be pro- \ncured. \n\nThe saline compounds of magnesia will require very \nlittle discussion as to their uses as manures. The most \nimportant relations of this subject to agriculture have \nbeen considered in the former part of this Lecture, when \nthe application of the magnesian limestone was exam- \nined. In combination with sulphuric acid magnesia \nforms a soluble salt, This substance, it is stated by \nsome inquirers, has been found of use as a manure ; but \nit is not found in nature in sufficient af)undance, nor is \nit capable of being made artiiicially sufficiently cheap to \nbe of useful application in the common course of hus- \nbandry. \n\n\n\n229 \n\nWood ashes consist principally of the vegetable alkali \nunited to carbonic acid ; and as this alkali is found in al- \nmost all plants, it is not difficult to conceive that it may \nform an essential part of their organs. The general \ntendency of the alkalies is to give solubility to vegetable \nmatters ; and in this way they may render carbonace- \nous and other substances capable of being taken up by \nthe tubes in the radical fibres of plants. The vegeta- \nble alkali likewise has a strong attraction for water, \nand even in small quantities may tend to give a due de- \ngree of moisture to the soil, or to other manures ; though \nthis operation from the small quantities used, or exist- \ning in the soil, can be only of a secondary kind. \n\nThe mineral alkali, or soda, is found in the ashes of \nsea-weed, and may be procured by certain chemical \nagencies from common salt. Common salt consists of \nthe metal named sodium, combined with chlorine ; and \npure soda consists of the same metal united to oxy- \ngene. When water is present, which can afford oxy- \ngene to the sodium, soda may be obtained in several \nmodes from salt. \n\nThe same reasoning will apply to the operation of \nthe pure mineral alkali, or the carbonated alkali, as to \nthat of the vegetable alkali ; and when common salts \nacts as a manure, it is probably by entering into the \ncomposition of the plant in the same manner as gypsum, \nphosphate of lime, and the alkalies. Sir John Pringlc \nhas stated, that salt in small quantities assists the de- \ncomposition of animal and vegetable matter. This cir- \ncumstance may render it useful in certain soils. Com- \nmon salt likewise is offensive to insects. \xe2\x80\x94 That in small \nquantities it is sometimes a useful manure, 1 believe it \nfully proved ; and it is probable that its efficacy depends \nupon many combined causes. \n\nSome persons have argued against the employment \nof salt; because when used in large quantities, it either \ndoes no good, or renders the ground sterile ; but this is \na very unfair mode of reasoning. That salt in large \nquantities rendered lands barren, was known long be- \nfore any records of agricultural science existed. We \nread in the Scriptures, that Abimclech took the city of \nShechem, ^^ and ]>eat down the city and sowed it with \n\n\n\n2m \n\nsalt J*\' that the soil might be for ever unliuitful. Vir- \ngil reprobates a salt soil ; and Fliny, though he recom- , \nmends giving salt to cattle, yet affirms, that when strew- \ned over land it renders it barren. But these are not ar- \nguments against a proper application of it. Refuse salt \nin Cornwall, which, however, likewise contains some \nof the oil and exuviae of fish, has long been known as \nan admirable manure. And the Chesliire farmers con- \ntend for the benefit of tlie peculiar produce of their \ncountry. \n\nIt is not unlikely, that the same causes influence the \neflects of salt, as those which act in modifying the ope- \nration of gypsum. Most lands in this island, particu- \nlarly those near the sea, probably contain a sufficient \nquantity of salt for all the purposes of vegetation ; and \nin such cases the supply of it to the soil will not only \nbe useless, but may be injurious. In great storms the \nspray of the sea has been carried more than 50 miles \nfrom the shore ; so that from this source salt must be \noften supplied to the soil. 1 have found salt in all the \nsandstone rocks that I have examined, and it must ex- \nist in the soil derived from these rocks. It is a constitu- \nent likewise of almost every kind of animal and vegeta- \nble manure. \n\nBesides these compounds of the alkaline earths and \nalkalies, many others have been recommended for the \npurposes of increasing vegetation ; such are nitrPy or \nthe nitrous acid combined with potassa. Sir Kenelin \nDigby states, that he made barley grow very luxuriantly \nby watering it with a very weak solution of nitre ; but \nhe is to speculative a writer to awaken confidence in his \nresults. This substance consists of one proportion of \nazote, six of oxygene, and one of potassium ; and it is \nnot unlikely that it may furnish azote to form albumen, \nor gluten, in those plants that contain them ; but the \nnitrous salts are too valuable for other purposes to be \nused as manures. \n\nDr. Home states, that sidphate of potassa, which as \n1 just now mentioned, is found in the ashes of some \npeats, is a useful manure. But Mr. Naismith* ques- \n\n* Elements of A^\'iiculture, p. 78. \n\n\n\n2ai \n\ntions his results ; and quotes experiments hostile to bis \nopinion, and, as he conceives, unfavourable to the eflB- \ncacy of any species of saline manure. \n\nMuch of the discordance of the evidence relating to \nthe eiTicacy of saline substances depends upon the cir- \ncumstance of their having been used in different pro- \nportions, and in general, in quantities much too large. \n\nI made a number of experiments in May and June, \n1807, on the effects of different saline substances on bar- \nley and on grass growing in the same garden, the soil \nof which was a light sand, of which 100 parts were \ncomposed of 60 parts of siliceous sand, and 24 parts \nfinely divided matter, consisting of seven parts carbon- \nate of lime, 12 parts alumina and silica, less than one \npart saline matter, principally common salt, with a \ntrace of gypsum and sulphate of magnesia : the remain- \ning 16 parts were vegetable matter. \n\nThe solutions of the saline substances were used \ntwice a week, in the quantity of two ounces, on spots of \ngrass and corn, sufficiently remote from each other to \nprevent any interference of results. The substances \ntried were siqier-carhonate^ sulphate, acetate, nitrate^ \nand muriate of potassa ; sulphate of soda, sulphate, \nnitrate, muriate, and carbonate of ammonia. 1 found, \nthat in all cases when the quantity of the salt equalled \none-thirtieth part of the weight of the water, tlie effects \nwere injurious ; but least so in the instances of tlie car- \nbonate, sulphate and muriate of ammonia. When the \nquantities of the salts w^ere one-three hundredth part of \nthe solution the effects were different The plants wa- \ntered with the solutions of the sulphates grew just in \nthe same manner as similar plants watered with rain \nwater. Those acted on by the solution of nitre, acetate, \nand super-carbonate of potassa, and muriate of ammo- \nnia, grew rather better. Those treated witli the solu- \ntion of carbonate of ammonia grew most luxuriantly of \nall. This last result is what might be expected," for \ncarbonate of ammonia consists of carbon, hydro^enc, \nazote, and oxygene. There was, however, another re- \nsult which I had not anticipated ; the plants watered \nwith solution of nitrate of ammonia did not grow better \nthan those watered with rain water. The solution red- \n\n\n\n2^2 \n\ndened litmus paper; and probably the free acid ex- \nerted a prejudicial effect, and interfered with the re- \nsult. \n\nSoot doubtless owes part of its efficacy to the ammo- \nniacal salt that it contains. The liquor produced by the \ndistillation of coal contains carbonate and acetate of am- \nmonia, and is said to be a very good manure. \n\nIn 1808, I found the growth of wheat in a field at \nKoehampton assisted by a very weak solution of acetate \nof ammonia. \n\nSoapers\' waste has been recommended as a manure, \nand it has been supposed that its efficacy depended upon \nthe different saline matters it contains ; but their quan- \ntity is very minute indeed, and its principal ingredients \nare mild lime and quicklime. In the soapers\' waste \nfrom the best manufactories, there is scarcely a trace of \nalkali. Lime moistened with sea water affords more \nof this substance, and is said to have been used in some \ncases with more benefit than common lime. \n\nIt is unnecessary to discuss to any greater extent the \neffects of saline substances on vegetation ; except the \nammoniacal compounds, or the compounds containing \nnitric, acetic, and carbonic acid ; none of them can af- \nford by their decomposition any of the common princi- \nples of vegetation, carbon, hydrogene, and oxygene. \n\nThe alkaline sulphates and the earthy muriates are \nso seldom found in plants, or are found in such minute \nquantities, that it can never be an object to aj)ply them \nto the soil. It was stated in the beginning of this Lec- \nture, that the earthy and alkaline substances seem ne- \nver to be formed in vegetation ; and there is every rea- \nson, likewise, to believe, that they are never decompo- \nsed ; for after being absorbed they are found in their \nashes. \n\nThe metallic bases of them cannot exist in contact \n\xe2\x80\xa2with aqueous fluids ; and these metallic 1)ases, like other \nmetals, have not as yet been resolved into any other \nforms of matter by artificial processes ; they cortibinc \nreadily with other elements ; but they remain undes- \ntructible, and can be traced undiminished in quantity^ \ntlirouffh tlieir diversified combinations. \n\n\n\nLECTURE VIll. \n\n\n\nOn the Improvement of Lands by Burning ; chemical \nPrinciples of this Operation. On Irrigation and its \nEffects. On Fallowing ; its Disadvantages and \nUses. On the convertible Husbandry founded on re- \ngular Rotations of different Crops. On Pasture ; \nViews connected with its Application. On various \nAgricultural Objects connected with Chemistry. Con- \nclusion, \n\ni HE improvement of sterile lauds by burning, was \nknown to the Romans. It is mentioned by Virgil in \nthe first book of the Georgics : " Sfepe etiam steriles \nincendere profuit agros." It is a practice still much in use \nin many parts of these Islands ; the theory of its opera- \ntion has occasioned much discussion, both amongst sci- \nentific men and farmers. It rests entirely itpon chemi- \ncal doctrines ; and 1 trust I shall be able to ofier you \nsatisfactory elucidations on the subject. \n\nThe basis of all common soils as I stated in the Fourth \nLecture, are mixtures of the primitive earths and oxide \nof iron ; and these earths have a certain degree of at- \ntraction for each other. To regard tliis attraction in its \nproper point of view, it is only necessary to consider the \ncomposition of any common siliceous stone. Feldspar, \nfor instance, contains sjliceons, aluminous, calcareous \nearths, fixed alkali, and oxide of iron, which exist in \none com|)Oinid, in consequence of their chemical attrac- \ntions for each other. Let this stone be ground into im- \npalpable powder, it then becomes a substance like clay: \nif the powder l)e heated very strongly it fuses, and on \ncooling forms a coherent mass similar to the original \nstone ; the parts separated by mechanical division ad- \nhere again in consequence of chemical attraction. If \nthe |)owder is heated less strongly the particles only su- \nperficially combine with each other, and form a gritty \n\n\n\n234 \n\nmass, which, when broken into pieces, has the charac- \nters of sand. , \n\nIf the power of the powdered feldspar to absorb wa- \nter from tlie atmosphere before, and after the applica- \ntion of the heat, be compared, it is found much less in \nthe last case. \n\nThe same eflect takes place when the powder of other \nsiliceous or aluminous stones is made the subject of ex- \nperiment. \n\nI found that two equal portions of basalt ground into \nimpalpable powder, of which one had been strongly ig- \nnited, and the other exposed only to a temperature equal \nto that of boiling water, gained very difterent weights \nin the same time when exposed to air. In four hours \nthe one had gained only two grains, whilst the other \nhad gained seven grains. \n\nWhen clay or tenacious soils are burnt, the effect \nis of the same kind ; they are brought nearer to a state \nanalogous to that of sands. \n\nIn the manufacture of bricks the general principle is \nwell illustrated ; if a piece of dry brick earth be appli- \ned to the tongue it will adhere to it very strongly, in \nconsequence of its power to absorb water ; but after it \nhas been burnt there will be scarcely a sensible adhe- \nsion. \n\nThe process of burning renders the soil less com- \npact, less tenacious and retentive of moisture ; and \nwhen properly applied, may convert a matter that was \nstiff, damp, and in consequence cold, into one pow- \ndery, dry, and warm ; and much more proper as a bed \nfor vegetable life. \n\nThe great objection made by speculative chemists to \nparing and burning, is, that it destroys vegetable and \nanimal matter, or the manure in the soil ; but in cases \nin which the texture of its earthy ingredients is perma- \nnently improved, there is more than a compensation for \nthis temporary disadvantage. And in some soils where \nthere is an excess of inert vegetable matter, the de- \nstruction of it must be beneficial ; and the carbonace- \nous matter remaining in the ashes may be more useful \nto the crop than the vegetable fibre, from which it was \nprod u fed. \n\n\n\n235 \n\nI have exauiiiied by a chemical analysis three spe- \ncimens of ashes from dillerent lands that had under- \ngone paring and burning. The first was a quantity sent \nto the Board by M. Boys of liellhanger, in Kent, \n.whose treatise on paring and burning has been pub- \nlished. They were from a chalk soil, and 200 grains \ncontained \n\n80 Carbonate of lime. \n11 Grypsum. \n! 9 Charcoal \n\n15 Oxide of iron. \n3 Saline matter. \nSulphate of potash. \n\nMuriate of magnesia, with a minute quan- \ntity of vegetable alkali. \nThe remainder alumina and silica. \n\nMr. Boys estimates that 2660 bushels are the com- \nmon produce of an acre of ground, which, according \nto his calculation would give 172900 lbs. containing \n\n\n\nCarbonate of lime \n\n\n69160 lbs. \n\n\nGypsum \n\n\n9509.5 \n\n\nOxide of iron \n\n\n12967.5 \n\n\nSaline matter \n\n\n2593.5 \n\n\nCharcoal - \n\n\n7780.5 \n\n\n\nIn this instance there was undoubtedly a very consi- \nderable quantity of matter capable of being active as \nmanure produced in the operation of burning. The \ncharcoal was very finely divided ; and exposed on a \nlarge surface on the field, must have been gradually \nconverted into carbonic acid. And gypsum and oxide \nof iron, as I mentioned in the last Lecture, seem to \nproduce the very best effects when applied to lands con- \ntaining an excess of carbonate of lime. \n\nThe second specimen was from a soil near Coleor- \nton, in Leicestershire, containing only four per cent, of \ncarbonate of lime, and consisting of three-fourths light \nsiliceous sand, and about one-fourth clay. This had \n\n\n\n> \nbeen iuii:\' bcfurc burning, and 100 parts uf the ashes \n\ngave. \n\n6 parts charcoal \n\n3 Muriate- of soda and sulphate of potash, \n\nAvitli a trace of vegetable alkali. \n9 Oxide of iron. \nAnd the remainder the earths. \n\nIn this instance, as in the otlier, iinely divided char- \ncoal was found ; the solubility of wliich would be in- \ncreased by the presence of the alkali. \n\nThe tiiird instance was, that of a stiif clay, from \nMount\'s Kay, Cornwall. This land had been brought \ninto cultivation from a lieath by burning about ten years \nbefore ; but having been neglected, furze was spring- \ning up in diifercnt parts of it, which gave rise to the se- \ncond paring and burning. 100 parts of the ashes con- \ntained \n\n8 parts of charcoal. \n\n2 of saline matter principally common s^t, \nwitli a little vegetable alkali. \n\n7 Oxide of iron. \n\n2 Carbonate of lime. \nRemainder alumina and silica. \n\nHere the quantity of charcoal was greater than in \nthe other instances. The salt, I suspect, was owing to \nthe vicinity of the sea, it being but two miles off. In \nthis land there was certainly an excess of dead vegeta- \nble fibre, as well as an i\\nprofitable living vegetable \nmatter ; and I have since heard that a great improve- \nment took place. \n\nMany obscure causes have been referred to for the \npurpose of explaining the effects of paring and burning; \nbut I believe they maybe referred entirely to the dimi- \nnution of the coherence and tenacity of clays, and to the \ndestruction of inert, and useless vegetable matter, and \nits conversion into a manure. \n\nDr. Darwin, in his Phytologia, has supposed, that \n\n\n\nclay during torrelaction, may absorb some nutritive prin- \nciples from the atmosphere that afterwards may be sup- \nplied to plants; but the earths are pure metallic oxides, \nsaturated with oxygene; and the tendency of burning is \nto expel any other volatile principles that they may con- \ntain in coml)ination. If the oxide of iron in soils is not \nsaturated with oxygene, torrefaction tends to produce \nits further union with this principle; and hence in burn- \ning, the colour of clays changes to red. Tl^e oxide of \niron containing its full [iroportion of oxygene has less \nattraction for acids than the other oxide, and is conse- \nquently less likely to be dissolved by any fluid acids in \nthe soil ; and it appears in this state to act in the same \nmanner as the earths. A very ingenious author, whom \nI quoted at the end of the last Lecture, supposes that \nthe oxide of iron when combined with carbonic acid is \npoisonous to plants ; and that one use of torrefaction is \nto expel- the carbonic acid from it ; but the carbonate of \niron is not soluble in water, and is a very inert substance; \nand I have raised a luxuriant crop of cresses in a soil \ncomposed of one-fifth carbonate of iron, and four-fifths \ncarbonate of lime. Carbonate of iron abounds in some \nof the most fertile soils in England, particularly the red \nhop soil. And there is no theoretical ground for sup- \nposing, that carbonic acid, which is an essential food of \nplants, should in any of its combinations be poisonous \nto. them ; and it is known that lime and magnesia are \nboth noxious to vegetation, unless combined with this \nprinciple. \n\nAll soils that contain too much dead vegetable fibre, \nand which consequently lose from one- third to one- half \nof their weight by incineration, and all such as contain \ntheir earthy constituents in an impalpable state of divi- \nsion, i. e. the stiff clays and marles, are improved by \nburning; but in coarse sands, or rich soils containing a \njust mixture of the earths; and in all cases in which the \ntexture is already sufficiently loose, or the organizablc \nmatter sufficiently soluble, the process of torrefaction \ncannot be useful. \n\nAll poor siliceous sands must be injured by it ; and \nhere practice is found to accord with theory. Mr. \nYoung, in his Essay on Manures, states, " that he found \n\n\n\n26S \n\nburning injure sand ;" and the operation is never per- \nformed by good agriculturists upon siliceous sandy \nsoils, after they have once been brought into cultiva- \ntion. \n\nAn intelligent farmer in Mount\'s Bay told me, that \nhe had pared and burned a small field several years ago, \nwhich he had not been able to bring again into good con- \ndition. 1 examined the spot, the grass was very poor \nand scanty, and the soil an arid siliceous sand. \n\nIrrigation or watering land, is a practice, which at \nfirst view appears the reverse of torrefaction ; and in ge- \nneral, in nature the operation of water is to bring earthy \nsubstances into an extreme state of division. But in the \nartificial watering of meadows, the beneficial effects de- \npend upon many different causes, some chemical, some \nmechanical. \n\nWater is absolutely essential to vegetation ; and when \nland has been covered with water in the winter, or in \nthe beginning of spring, the moisture that has penetra- \nted deep into the soil, and even the subsoil, becomes a \nsource of nourishment to the roots of the plant in the \nsummer, and prevents those bad effects that often hap- \npen in lands in their natural state, from a long continu- \nance of dry weather. \n\nWhen the water used in irrigation has flowed over a \ncalcareous country, it is generally found impregnated \nwith carbonate of lime ; and in this state it tends, in \nmany instances, to ameliorate the soil. \n\nCommon river water also generally contains a certain \nportion of organizable matter, which is much greater \nafter rains, than at other times ; and which exists in \nthe largest quantity when the stream rises in a cultiva- \nted country. \n\nEven in cases when the water used for flooding is \npure and free from animal or vegetable substances, it \nacts by causing the more equable diffusion of nutritive \nmatter existing in the land ; and in very cold seasons it \npreserves the tender roots and leaves of the grass from \nbeing affected by frost. \n\nWater is of greater specific gravity at 42\xc2\xae Fahren- \nheit, than at 32\xc2\xb0, the freezing point ; and hence in a \nmeadow irrigated in winter, the water immediately in \n\n\n\n239 \n\ncontact with the grass is rarely below 40^; a degree of \ntemperature not at all prejudicial to the living organs of \nplants. \n\nIn 1804, in the month of March, I examined the tem- \nperature in a water meadow near Hungerford, in Berk- \nshire, by a very delicate thermometer. The tempera- \nture of the air at seven in the morning was 29*^. The \nwater w^as frozen above the grass. The temperature of \nthe soil below the water in which the roots of the grass \nwere fixed, was 43^. \n\nIn general those waters which breed the best fish are \nthe best fitted for watering meadows ; but most of the \nbenefits of irrigation may be derived from any kind of \nwater. It is, however, a general principle, that waters \ncontaining ferruginous impregnations, though possess- \ned of fertilizing effects, when applied to a calcareous \nsoil, are injurious on soils that do not effervesce with \nacids; and that calcareous waters which are known by \nthe earthy deposit they afford when boiled, are of most \nuse on siliceous soils, or other soils containing no re- \nmarkable quantity of carbonate of lime. \n\nThe most important processes for improving land, are \nthose which have been already discussed, and that are \nfounded upon the circumstance of removing certain con- \nstituents from the soil, or adding others or changing \ntheir nature ; but there is an operation of very ancient \npractice still much employed, in which the soil is expo- \nsed to the air, and submitted to processes which are \npurely mechanical, namely , fallowing. \n\nThe benefits arising from fallows have been much \nover-rated. A summer fallow, or a clean fallow, may \nbe sometimes necessary in lands overgrown with weeds, \nparticularly if they are sands which cannot be pared \nand burnt with advantage; but is certainly unprofitable \nas part of a general system in husbandry. \n\nIt has been supposed by some writers, that certain \nprinciples necessary to fertility are derived from the at- \nmosphere, which are exhausted by a succession of crops, \nand that these are again supplied during the repose of \nthe land, and the exposure of the pulverized soil to the \ninfluence of the air ; but this in truth is not the case. \nThe earths commonly found in soils cannot be combined \n\n\n\n240 \n\nwith move oxygeuc ; none of them unite to azote ; and \nsuch of them as arc capable of attracting carbonic acid, \nare always saturated with it in those soils on which the \npractice of fallowing is adopted. The vague ancient \nopinion of the use of nitre, and of nitrous salts in ve- \ngetation, seems to have been one of the principal spe- \nculative reasons for the defence of summer fallows. \n^Nitrous salts are produced during the exposure of soils \ncontaining vegetable and animal remains, and in greatest \nabundance in hot weather ; but it is probably by the \ncombination of azote from these remains with oxygene \nin the atmosphere that the acid is formed ; and at the \nexpense of an element, which otherwise would have \nformed ammonia ; the compounds of which, as is evi- \ndent from what was stated in the last Lecture, are much \nmore efficacious than the nitrous compounds in assisting \nvegetation. \n\nWhen weeds are buried in the soil, by their gradual \ndecomposition they furnish a certain quantity of soluble \nmatter ; but it may be doubted whether there is as \nmuch useful manure in the land at the end of a clean \nfallow, as at the time the vegetables clothing the sur- \nface were first ploughed in. Carbonic acid gas is form- \ned during the whole time by the action of the vegeta- \nble matter upon the oxygene of tlie air, and the greater \npart of it is lost to the soil in wliich it was formed, and \ndissipated in the atmosphere. \n\nThe action of the sun upon the surface of the soil \ntends to disengage the gaseous and the volatile fluid \nmatters that it contains ; and heat increases the rapidity \nof fermentation : and in the summer fallow, nourish- \nment is rapidly produced, at a time when no vegetables\' \nare present capable of absorbing it. \n\nLand, when it is not employed in preparing food for \nanimals, should be applied to the purpose of the pre- \nparation of manure for plants ; and this is effected by \nmeans of green crops, in consequence of the absorption \nof carbonaceous matter in the carbonic acid of tl/e at- \nmosphere. In a summer\'s fallow a period is always \nlost in which vegetables may be raised, cither as food \nfor animals, or as nourishment for the next crop ; and \nthe texture of the soil is not so much improved by its \n\n\n\n241 \n\nexposure as in winter, when the expansive powers of \nice, tlie gradual dissolution of snows, and the alterna- \ntions from wet to dry, tend to pulverize it, and to mix \nits different parts together. \n\nIn the drill husbandry the land is preserved clean by \nthe extirpation of the weeds by hand, and by raising \nthe crops in rows, which renders the destruction of the \nweeds much more easy. Manure is supplied either by \nthe green crops themselves, or from the dung of the cat- \ntle fed upon them ; and the plants having large sys- \ntems of leaves, are made to alternate with those bear- \ning grain. \n\nIt is a great advantage in the convertible system of \ncultivation, that the whole of the manure is employed ; \nand that those parts of it which are not fitted for one \ncrop, remain as nourishmeut for another. Thus, in Mr. \nCoke\'s course of crops, the turnip is the first in the or- \nder of succession ; and this crop is manured with recent \ndung, which immediately affords sufficient soluble mat- \nter for its nourishment ; and the heat produced in fer- \nmentation assists the germination of the seed and the \ngrowth of the plant. After turnips, barley with grass \nseeds is sown ; and the laud having been little exhaust- \ned by the turnip crop, affords the soluble parts of the \ndecomposing manure to the grain. The grasses, rye \ngrass, and clover remain, which derive a small part \nonly of their organized matter from the soil, and proba- \nbly consume the gypsum in the manure which would be \nuseless to other crops : these plants likewise by their \nlarge systems of leaves, absorb a considerable quantity \nof nourishment from the atmosphere; and wlien plough- \ned in at the end of two years, the decay of their roots \nand leaves affords manure for tlie wheat crop ; and at \nthis period of the course, the woody fibre of the farm- \nyard manure which contains the phosphate of lime and \nthe other difficultly soluble parts, is broken down ; and \nas soon as the most exhausting crop is taken, recent ma- \nnure is again applied. \n\nMr. Gregg, iwliose very enlightened system of culti- \nvation has been published by the Board of Agriculture, \nand who has the merit of first adopting a plan similar \nto Mr. Coke\'s upou strong clays, suffers tlie ground af- \n\nM b \n\n\n\n242 \n\nter barley to remain at rest for two years in grass ; sows^ \npeas and beans on the leys; ploughs in the pea or bean \nstubble for wheat ; and in some instances, follows his \nwheat crops by a course of winter tares and winter bar- \nley, which is eat off in the spring, before the land is \nsowed for turnips. \n\nPeas and beans, in all instances, seem well adapted \nto prepare the ground for wheat ; and in some rich \nlands, as in the alluvial soil of the Parret, mentioned \nin the Fourth Lecture, and at the foot of the South \nDowns in Sussex, they are raised in alternate crops for \nyears together. Peas and beans contain, as appears \nfrom the analysis in the Third Lecture, a small quan- \ntity of a matter analogous to albumen ; but it seems that \nthe azote which forms a constituent part of this matter, \nis derived from the atmosphere. The dry bean leaf, \nwhen burnt, yields a smell approaching to that of de- \ncomposing animal matter; and in its decay in the soil, \nmay furnish principles capable of becoming a part of \nthe gluten in wheat. \n\nThough the general composition of plants is very an- \nalogous, yet the specific difference in the products of \nmany of them, and the facts stated in the last Lecture, \nprove that they must derive different materials from the \nsoil; and though the vegetables having the smallest \nsystems of leaves will proportionably most exhaust the \nsoil of common nutritive matter, yet particular vegeta- \nbles when their produce is carried oft", will require pe- \nculiar principles to be supplied to the land in which they \ngrow. Strawberries and potatoes at first produce lux- \nuriantly in virgin mould, recently turned up from pas- \ntufe ; but in a few years they degenerate, and require a \nfresh soil ; and the organization of these plants is such, \nas to be constantly producing the migration of their lay- \ners : thus the strawberry, by its long shoots, is constant- \nly endeavouring to occupy a new soil ; and the fibrous \nradicles of the potato produce bulbs at a considerable \ndistance from the parent plant. Lands, in a course of \nyears, often cease to aflbrd good cultivated grasses; \nthey become (as it is popularly said) tired of them^ and \none of the probable reasons for this was stated in the \nlast Lecture. \n\n\n\n24:i \n\nThe most remarkable instance of the powers of ve- \ngetables to exhaust the soil of certain principles neces- \nsary to their growth is found in certain funguses. Mush- \nrooms are said never to rise in two successive seasons \non the same spot; and the production of tlie phsenome- \nna called fairy rings has been ascribed by Dr. Wollas- \nton to the power of the peculiar fungus which forms it, \nto exhaust tlie soil of the nutriment necessary for tlie \ngrowth of the species. The consequence is, that the \nring annually extends ; for no seeds will grow where \ntheir parents grew before them ; and the interior part of \nthe circle has been exhausted by preceding crops ; but \nwhere the fungus has died, nourishment is supplied for \ngrass, which usually rises within the circle, coarse, and \nof a dark green colour. \n\nWhen cattle are fed upon land not benefited by their \nmanure, the eflPect is always an exhaustion of the soil ; \nthis is particularly the case where carrying horses are \nkept on estates ; they consume the pasture during the \nnight, and drop the greatest part of tlieir manure in the \nday during their labour in the daytime. \n\nThe exportation of grain from a country, unless some \narticles capable of becoming manure are introduced in \ncompensation, must ultimately tend to exhaust the soil. \nSome of the spots, now desart sands in northern x^fri- \nca, and Asia Minor, w^ere anciently fertile. Sicily was \nthe granary of Italy ; and the quantity of corn carried \noff from it by the Romans, is probably a chief cause of \nits present sterility. In this island, our commercial \nsystem at present has the effect of affording substances, \nwhich in their use and decomposition must enrich the \nland. Corn, sugar, tallow, oil, skins, furs, Avine, silk, \ncotton, ^c. are imported, and iish are supplied from \nthe sea. Amongst our numerous exports woollen, and \nlinen, and leather goods, are almost the only substances \nwhich contain any nutritive materials derived from the \nsoil. \n\nIn all courses of crops it is necessary that every part \nof the soil should be made as useful as possi!)le to the \ndifferent plants ; but the depth of the furrow in plough- \ning must depend upon the nature of the soil, and of the \n\n\n\n244 \n\nsubsoil. Ill I\'ich clayey soils the furrow can scarcely \nbe too deep ; and even in sands, unless the subsoil con- \ntains some principles noxious to vegetables, the same \npractice should be adopted. When the roots are deep, \nthey are less liable to be injured, either by excess of \nrain, or drought ; the layers shoot forth their radicles \ninto every part of the soil ; and the space from which \nthe nourishment is derived is more considerable, than \n"when the seed is superficially inserted in the soil. \n\nThere has been much diflference of opinion with re- \nspect to permanent pasture ; but the advantages or dis- \nadvantages can only be reasoned upon according to the \ncircumstances of situation and climate. Under the cir- \ncumstances of irrigation, lands are extremely produc- \ntive, with comparatively little labour ; and in climates \nwhere great quantities of rain falls, the natural irriga- \ntion produces the same effects as artificial. When hay \nis in great demand, as sometimes happens in the neigh- \nbourhood of the metropolis, where manure can be easily \nprocured, the application of it to pasture is repaid for \nby the increase of crop ; but top-dressing grass land \nwith animal or vegetable manure, cannot be recommend- \ned as a general system. Dr. Coventry very justly ob- \nserves, that there is a greater waste of the manure in \nthis case, than when it is ploughed into the soil for seed \ncrops. The loss by exposure to the air, and the sun- \nshine, offer reasons in addition to those that have been \nalready quoted in the Sixth Lecture, for the application \nof manure even in this case, in a state of incipient, and \nnot completed fermentation. \n\nVery little attention has been paid to the nature of \nthe grasses best adapted for permanent pasture. The \nchief circumstance which gives value to a grass, is the \nquantity of nutritive matter that the whole crop will af- \nford ; but the time and duration of its produce are like- \nwise points of great importance ; and a grass that sup- \nplies green nutriment throughout the whole of the year, \nmay be more valuable than a grass which yields its pro- \nduce only in summer, though the whole quantity of food \nsupplied by it should be much less. \n\nThe grasses that propagate themselves by layers, the \n\n\n\n245 \n\ndifferent species of Agrostis, supply pasture throughout \nthe year ; and, as it has been mentioned on a former \noccasion, the concrete sap stored up in their joints, ren- \nders them a good food even in winter. I saw four square \nyards of iiorin grass cut in the end of January, this year, \nin a meadqw exclusively appropriated to the cultivation \nof florin, by the Countess of Hardwicke, the soil of \nwhich is a damp stiff clay. They afforded 28 pounds \nof fodder ; of which 1000 parts afforded, 64 parts of \nnutritive matter, consisting nearly of one-sixth of sugar, \nand five- sixths of mucilage, with a little extractive mat- \nter. In another experiment, four square yards gave 27 \npounds of grass. The quality of this grass is inferior \nto that of the florin referred to in the Table, in the lat- \nter part of the Third Lecture, which was cultivated by \nSir Joseph Banks in Middlesex, in a much richer soil, \nand cut in December. \n\nThe florin grass, to be in perfection, requires a moist \nclimate or a wet soil, and it grows luxuriantly in cold \nclays unfltted for other grasses. In light sands, and in \ndry situations, its produce is much inferior as to quan- \ntity and quality. \n\nThe common grasses, properly so called, that afford \nmost nutritive matter in early spring, jwe the vernal mea- \ndow grass, and meadow fox-tail grass ; but their pro- \nduce at the time of flowering and ripening the seed are \ninferior to that of a great number of other grasses ; their \nlatter- math, is, however, abundant. \n\nTall fescue grass stands highest, according to the ex- \nperiments of the Duke of Bedford, of any grass, proper- \nly so called, as to the quantity of nutritive matter afford- \ned by the whole crop when cut at the time of flowering ; \nand meadow cat\'s-tail grass affords most food when cut \nat the time the seed is ripe; the highest latter-math pro- \nduce of the grasses examined in the Duke of Bedford\'s \nexperiments is from the sea meadow grass. \n\nNature has provided in all permanent pastures a mix- \nture of various grasses, the produce of which differs at \ndifferent seasons. Where pastures are to be made ar- \ntificially, such a mixture ought to be imitated; and, per- \nhaps, pastures superior to the natural ones may be made \n\n\n\n\xe2\x80\xa2Mb \n\nby selecting due proportions of those species of gi\'asses \nfitted for the soil, which afford respectively the greatest \nquantities of spring, summer, latter-math, and winter \nproduce ; a reference to the details in the Appendix will \nshew that such a plan of cultivation is very practica- \nble. \n\nIn all lands, whether arable or pasture, weeds of every \ndescription should be rooted out before the seed is ripe ; \nand if they are suffered to remain iu hedge rows, they \nshould be cut when in flower, or before, and made into \nheaps for manure ; in this case they will furnish more \nnutritive matter in their decomposition ; and their in- \ncrease by the dispersion of seeds will be prevented. \nThe farmer, who suffers weeds to remain till their ripe \nseeds are shed, and scattered by the winds, is not only \nhostile to his own interests, but is likewise an enemy to \nthe public : a few thistles neglected will soon stock a \nfarm ; and by the light down which is attached to their \nseeds, they may be distributed over a whole country. \nNature has provided such ample resources for the con- \ntinuance of even the meanest vegetable tribes, that it is \nvery difficult to ensure the destruction of such as are \nhostile to the agriculturist, even with every precaution. \nSeeds excluded from the air, will remain for years in- \nactive in the soil,* and yet germinate under favourable \ncircumstances ; and the different plants, the seeds of \nwhich, like those of the thistle and dandelion, are fur- \nnished with beards or wings, may be brought from an \nimmense distance. The fleabane of Canada has only \nlately been found in Europe ; and Linnseus supposes \nthat it has been transported from America, by the very \nlight downy plumes with which the seed is provided. \n\n* The appearance of seeds in places where their parent plants are not \nfound may be easily accutinted for from this circumstance and olher \ncircumstances. Many seeds are carried from island to island by cur- \nrents in the sea, and are defended by their hard coats from the im- \nmediate acdon of the water. West Indian seeds (of this description) \nare often found on our coasts, and readily germinate : their lcu>g voy- \naf;e having been barely sufficient to afford the cotyledon its due pro- \nportion of moisture. Other seeds are carried indigested in the sto- \nmach of birds, and supplied with food at the moment of their depo- \nsition. The light seeds of the mosses and lichens probably float in \nevery part of the atmosphere, and abound on the surface of the sea. \n\n\n\n247 \n\nIn feeding cattle with green food, there are many ad- \nvantages in soiling, or supplying them with food, where \ntheir manure is preserved, out of the field ; the plants \nare less injured when cut, than when torn or jagged by \nthe teeth of the cattle, and no food is wasted by being \ntrodden down. They are likewise obliged to feed with- \nout making selection ; and in consequence the whole \nfood is consumed : the attachment, or dislike to a par- \nticular kind of food exhibited by animals, offers no proof \nof its nutritive powers. Cattle at first refuse linseed \ncake, one of the most nutritive substances on which they \ncan be fed.* \n\n* For the following observations on the selection of different kinds \nof common food by sheep and cattle I am obliged to Mr. George \nSinclair. \n\n" Lolium fierenne, rye grass. Sheep eat this grass when it is in \nthe early stage of its growth, in preference to most others ; but af- \nter the seed approaches towaijds perfection, they leave it for almost \nany other kind. A field in the Park at Woburn was laid down in \ntwo equal parts, one part with rye grass and white clover, and the \nother part with cock\'s-foot and red clover : from the spring till mid- \nsummer the sheep kept almost constantly on the rye grass ; but after \nthat time they left it, and adhered with equal constancy to the cock\'s- \nfoot during the remainder of the season. \n\nDactylis glomerata^ cock\'s-foot. Oxen, horses, and sheep, eat this \ngrass readily. The oxen continue to eat the straws and flowers from \nthe time of flowering till the time of perfecting the seed ; this was \nexemplified in a striking manner in the field before alluded to. The \noxen generally kept to the cock\'s-foot and red clover, and the sheep \nto the rye-grass and white clover. In the experiments published in \nthe Aiiioeuitates Academicae, by the pupils of Linnaeus, it is asserted \nthat this grass is rejected by oxen ; the above fact, however, is in \ncontradiction of it. \n\nAlofiecurus firatensis, meadow fox-tail. Sheep and horses seem \nto have a greater relish for this grass than oxen. It delighls in a soil \nof intermediate quality as to moisture or dryness, and is very produc- \ntive. In the water-meadow at Priestley, it constitutes a considerable \npart of the produce of that excellent meadow. It there keeps inva- \nriably possession of the top of the ridges, extending generally about \nsix feet from each side of the watercourse ; the space below that, to \nwhere the ridge ends, is stocked with cock\'s foot, rough stalked mea- \ndow grass, Festuca /iratensis, Fcstuca duriuscuia^ ji[^rostis stolonijc- \nra Agrostis /talus tris, and sweet-scented vernal grass, with a small \nadmixture of some other kinds. \n\nP/ileuDi firatense, meadow cat\'s-tail. This grass is eaten without \nreserve, by oxen, sheep, and horses. Dr. Pulteney says, that it is dis- \nliked by sheep ; but in pastures where it abounds, it does not appear \nrobe rcjijcted bv these animals; but etucn ia cotninon viih S;ucb \n\n\n\n248 \n\nWhen food artificially composed is to be given to \ncattle, it should be brought as nearly as possible to the \nstate of natural food. Thus, when sugar is given to \n\nothers as are growing with it. Hares are remarkably fond of it. The \nPhleum nodosum^ Fhleum alfiinum,, Foa fertilise and Poa comfiressa^ \nwere left untouched, although they were closely adjoining to it. It \nseems to attain the greatest perfection in a deep rich loam. \n\njigrostis stolonifera, florin. In the Experiments detailed in the \nAmoenitates Academicse, it is said, that h-irses, sheep, and oxen, eat \nthis grass readily. On the Duke of Bedford\'s farm at Maulden, flo- \nrin hay was placed in the racks belore horses in small distinct quan- \ntities ; alternately with common hay ; but no decided preference for \neither was manifested by the horses in this trial. But that cows and \nhorses prefer it to hay, when in a green state, seems fully proved by \nDr. Richardson, in his several publications on Fiorin ; and of its pro- \nductive powers in England (which has been doubted by some,) there \nare satisfactory proofs. Lady Hardwicke has given an account of a \ntrial of this grass, wherein twenty-three milch cows, and one young \nhorse, besides a number of pigs, were kept a fortnight on the pro- \nduce of one acre. \n\nPoa (rivialis, rough-stalked meadow. Oxen, horses, and sheep, \neat this grass with avidity. Hares also eat it ; but they give a de- \ncided preference to the smooth-stalked meadow-grass, to which it is, \nin many respects nearly allied. \n\nPoa /iratensis, smooth-stalked meadow grass. Oxen and horses \nare observed to eat this grass in common with others ; but sheep \nrather prefer the hard fescue, and sheeps\' fescue, which affect a si- \nmilar soil. This species exhausts the soil in a greater degree than \nalmost any other species of grass ; the roots being numerous, and \npowerfully creeping, become in two or three years completely matted \ntogether ; the produce diminishes as this takes place. It grows \ncommon in some meadows, dry banks, and even on walls. \n\nCijnosurus cristatus^ crested dog\'s-tail grass. The South Down \nsheep, and deer, appear to be remarkably fond of this grass: in \nsome parts of Woburn Park this grass forms the principal part of \nthe herbage on which these animals chiefly browse : while another \npart of the Park, that contains the Jgrostis cafiilaris, Jgrostis, fiu- \nmiliSy Festuca ovina, Fentuca duriuscula, and F\'estuca cambrica^ is \nseldom touched by them ; but the Welch breed of sheep almost \nconstantly browse upon these, and neglect the Cynosurus cristatusy \nLolium perenne^ and Poa trivialis. \n\nAgrostis vulgaris [cafiillariSf Linn.,) fine bent ; common bent. \nThis is a very common grass on all poor dry sandy soils. It is not \npalatable to cattle, as they never eat it readily, if any other kinds be \nwithin their reach. The Welch sheep, however, prefer it as I be- \nfore observed ; and it is singular, that those sheep being bred in the \npark, when some of the best grasses are equally within their reach, \nshould still prefer those grasses which natuially grow on the Welch \nmountains ; it seems to argue that such a preference is the effect ot \nsome other cause, than that of habit. \n\nFestuca ovina, sheeps\' fescue. All kinds of cattle relish this \n\n\n\n249 \n\nthem; some dry fibrous matter should be mixed with it, \nsuch as chopped straw, or dry withered grass, in order \nthat the functions of tiie stomach and bowels may be \n\ngrass; but it appears from the trial that has been made with it on \nclayey soils, that it continues but a short time in possesbion of such, \nbeing soon overpowered by the most luxuriant kinds. On diy shal- \nlow soils that are incapable of producing the larpjer sorts, this should \nform the principal crop, or rather the whole ; for it is seldom or \nnever, in its natural state, found intimately mixed with others; but \nby itself. \n\nFestuca duriuscula, hard fescue grass. This is certainly one of \nthe best of the dwarf sorts of grasses. It is grateful to all kinds of \ncattle ; hares are very fond of it : they cropped it close to the roots, \nand neglected the Fustuca ovina., and Fustuca rubra, which were \ncontiguous to it. It is present in most good meadows and j)astures. \n\nFestuca firatensis, meadow fescue. Tiiis gruss is seldom absent \nfrom rich meadows and pastures ; it is observed to be highly grate- \nful to oxen, sheep, and horses, particularly the former. It appears \nto grow most luxuriantly when combined with the hard fescue, and \nFoa trivialis. \n\njivena eliator, tall oat-grass. This is a very productive grass, fre- \nquent in meadows and pastures, but is disliked by cattle, particularly \nby horses ; this, perfectly, agrees with the small portion of nutritive \nmatter which it affords. It seems to thrive best on a strong tena- \ncious clay. \n\nAvena JIavescens, yellow oat-grass. This grass seems partial to \ndry soils, and meadows, and appears to be eaten by sheep and oxen, \nequally with the meadow barley, crested dog\'s tail and sweet-scented \nvernal grasses, which naturally grow in company with it. It nearly \ndoubles the quanlity of its produce by the application of calcareous \nmanure. \n\nHolcus lanatus^ meadow soft grass. This is a very common grass, \nand grows on all soils, from the richest to the poorest. It affords an \nabundance of seed, wiiich is light, and easily dispersed by the wind. \nIt appears to be generally disliked by all sorts of cattle. The pro- \nduce is not so great as a view of it in fields would indicate ; but \nbeing left almost entirely untouched by cattle, it appears as the most \nproductive part of the herbage. The hay which is made of it, from \nthe number of downy hairs which cover the surface of the leaves, \nis soft and spongy, and disliked by cattle in general. \n\nAnthoxanthum odoratum., sweet-scented vernal grass. Horses, \noxen, and sheep, eat this grass; though in pastures where it is com- \nbined with the meadow fox-tail, and white clover, cock\'s-foot, rough- \nstalked meadow, it is left untouched, from which it would seem un- \npalatable to cattle. Mr. Grant, of Leighton, laid down one half a \nfield of a considerable extent with this grass, combined with white \nclover. The other half of the field with foxtail and red clover. \nThe sheep would not touch the sweet-scented vernal, but kept con- \nstantly upon the fox-tail. The writer of this, saw the field when the \ngrasses were in the highest state of perfection ; and hardly any tiring \n\nI i \n\n\n\n250 \n\nperformed in a natural manuer. The principle is the \nsame as that of the practice alluded to ia the Third \nLecture, of giving chopped straw with harley. \n\nIn washing sheep, the use of water containing car- \nbonate of lime should be avoided ; for this substance de- \ncomposes the yolk of the wool, which is an animal soap, \nthe natural defence of the wool ; and wool often washed \nin calcareous water, becomes roagli and more brittle. \nThe finest wool, sucli as tliat of the Spanish and Saxou \nsheep, is most abundant in yolk. M. Vauquelin has \nanalysed several different species of yolk, and has found \nthe principal part of all of them a soap, with a basis of \npotassa, (i. e. a compound of oily matter and potassa,) \nwith a little oily matter in excess. He has found in \nthem, likewise, a notable quantity of acetate of potassa, \nand minute quantities of carbonate of potassa and mu- \nriate of potassa, and a peculiar odorous animal matter. \n\nM. Vauquelin states, that he found some specimens \nof wool lose as much as 45 per cent, in being deprived \nof their yolk ; and the smallest loss in his experiments \nwas 35 per cent. \n\nThe yolk is most useful to the wool on the back of \nthe sheep in cold and wet seasons ; probably the appli- \ncation of a little soap of potassa, with excess of grease \nto the sheep brought from warmer climates in our win- \nter, that is increasing their yolk artificially, might be \nuseful in cases where tiie fineness of the wool is of great \nimportance. A mixture of this kind is more conforma- \nble to nature, than that ingeniously adopted by Mr. \nBlakewell ; but at the time his labours commenced, the \nchemical nature of the yolk was unknown. \n\ncould be more satisfactory. Equal quantities of the seeds of white \nclover, were sown with each of the grasses; but from the dwarf na- \nture of the sweet-scented vernal grass, the clover mixed with it had \nattained to greater luxuriance, than that mixed with the meadow \nfoxtail." \n\n\n\n251 \n\n\n\nI have now exhausted all the subjects of (li.scussiouj> \nwhich my experience or information has been able to \nsupply on the connexion of chemistry with agriculture. \n\n1 venture to hope, that some of the views brought \nforward, may contribute to the improvement of the most \nimportant and useful of the arts. \n\nI trust that the inquiry will be pursued by others ; \nand that in proportion as chemical philosophy advances \ntowards perfection, it will afford new aids to agriculture. \n\nThere are sufficient motives connected both with \npleasure and profit, to encourage ingenious men to pur- \nsue this new path of investigation. Science cannot \nlong be despised by any persons as the mere specula- \ntion of theorists ; but must soon be considered by all \nranks of men in its true point of view, as the refine- \nment of common sense, guided by experience, gradually \nsubstituting sound and rational principles, for vague \npopular prejudices. \n\nThe soil offers inexhaustible resources, which, when \nproperly appreciated and employed, must increase our \nwealth, our population, and our physical strength. \n\nWe possess advantages in the use of machinery, and \nthe division of labour, belonging to no other nation. \nAnd the same energy of character, the same extent of \nresources which have always distinguished the people \nof the British Islands, and made tliem excel in arms, \ncommerce, letters, and philosophy, apply with the hap- \npiest effect to the improvement of the cultivation of the \nearth. Nothing is impossible to labour, aided by in- \ngenuity. The true objects of the agriculturist are like- \nwise, those of the patriot. Men value most what they \nhave gained with effort ; a just confidence in their own \xe2\x80\xa2 \npowers results from success ; they love their country \nbetter, because they have seen it improved by their own \ntalents and industry ; and they indentify with their in- \nterests, the existence of those institutions which have \nafforded them security, independence, and the multiplied \nf^njoyments of civilized life. \n\n\n\nAPPENDIX. \n\n\n\nVCCOUNT OF THE RESULTS \n\n\n\nEXPERIMENTS ON THE PRODUCE AND NUTRITIVE Ql^LI- \nTIES OF DIFFERENT GRASSES, \n\nAND OTHER PLANTS, \n\nISED AS THE FOOD OF ANIMALS. \n\nISSTITtTTED BT \n\nJOHN. DUKE OF BEDFORD. \n\n\n\nINTRODIIC rrioN \n\n\n\nnr Tin: Kin toil \n\n\n\nOf the 215 proper grasses which are capahle of being \ncultivated in this climate two only have heen employed \nto any extent for niakini; artificial |)astnres, rye grass \nand cock\'s-foot grass; and their a[)j)lication for this pur- \npose seems to have heen rather the result of accident, \nthan of any proofs of their superiority over other grasses. \n\nA knowledge of the comparative merits and value of \nall the dillerent species and varieties of grasses ciiririot \nfail to he of the highest importance in practical agricul- \nture. The hope of obtaining this knowledge was the \nmotive that in(lu(\'ed the Duke of Jiedford to institute \nthis series of experiments. \n\nSpots of ground, each containing four square feet, in \nthe garden at Woburn Abbey, were enclosed by iioards \nin such a manner that there was no lateral communica- \ntion between the earth included by the boards, and that \nof the garden. \'I\'he soil was removed in these enclo- \nsures, and new soils supplied ; or mixtiire of soils were \nmade in them, to furnish as far as possible to the diller- \nent grasses those soils which seem most favourable to \ntheir growth; a few varieties being adopted for the pur- \npose of ascertaining the eil\'ect of diilereut soils in the \nsame plant. \n\nThe grasses were either planted or sown, and their \nproduce cat and collected and dried, at the pro[)er sea- \nsons, in summer an<l autumn, by Mr. Sinclair, his \nGrace\'s gardener. For the purpose of determining as \nfar as possible the nutritive powers of the dilfei eiit spe- \ncies, equal weights of the dry grasses or vegetable sub- \nstances were acted upon by hot water till all their solu- \nble parts were dissolved ; the solution was then evapu \n\n\n\n256 \n\nrated to dryness by a gentle heat in a proper stove, and \nthe matter obtained carefully weighed. This part of \nthe process was likewise conducted witli much address \nand intelligence by Mr. Sinclair, by whom all the fol- \nlowing details and calculations are furnished. \n\nThe dry extracts supposed to contain the nutritive \nmatter of the grasses, were sent to me for chemical ex- \namination, lihe composition of some of them is stated \nin the table, page 106; 1 shall offer a few chemical ob- \nservations on others at the end of this Appendix. It \nwill be found from the general conclusions that the mode \nof determining the nutritive power of the grasses, by the \nquantity of matter they contain soluble in water, is suffi- \nciently accurate for all the purposes of agricultural in- \nvestigation. \n\n\n\nBOOKS QUOTED IN THE FOLLOWING PAGES. \n\nCurt. Lond. \xe2\x80\x94 Flora Lomlincnsis. By William Curtis, 2 vols. London ir98, fol. \nFI. Dan, \xe2\x80\x94 Flora Danica, or Icones Plantarum sponte nascentium in Regnis \n\nDaniac et Norvegix, editae a Ge. ^?ider. Hafnise 1761, f\'ol. \nEngl. Bot. \xe2\x80\x94 English Botany, by J. E Smith, M. D. ; the Figures by J. Sower- \n\nby, London 1790, 8vo. \nW. B. \xe2\x80\x94 Botanical arrangements By Dr. Withering. London 1801, 4 vol. \nHuds. \xe2\x80\x94 Hudson! Flora Anglica, 1778, vol. ii. \nHost. G. A. \xe2\x80\x94 Nic \'J lioniae Host Iconcs et Descriptiones Gramlnum Austria- \n\ncoruni, vol. i. \xe2\x80\x94 iii. ^\'illdobollae, 18U1, fol. \nHort. Kew. \xe2\x80\x94 Hortus Kewcnsis. By \\V. J. Aiton, vol. i. London 1810. \n\n\n\nK k \n\n\n\n258 \n\n\n\nBetaik of experiments on Grasses. By George Sinclaib, Gardener to his Grace \nthe UiTKE of Bbdfokd, and Corresp07iding Member of the Horticultural Society \nof Edinburgh. \n\n1. Anthoxanth7im odoratum, Eng\'l, Bot. 647. \xe2\x80\x94 Curt. Lond. Sweet-scented ver- \nnal grass. Nat. of Brit. \n\nAt the time of flowering\', the produce from the space of an acre equal to \n,000091827364 of a brown sandy loam with manure, is \n\noz. or lbs per acre \n\nGraes 11 oz. 8 Jr.* The produce per acre - 125235 = 7827 2 \n\n80 rfr. of irrass weigh when dry 21^ dr 1 ggg^g q = 2103 8 \nThe produce of the space, ditto 49.1-j-o 3 \nThe weight lost by the produce of one acre in \n\ndiying 5723 10 \n\n64</r. of gras- afford of nutritive matter 1 f/r. > jg^g jg \xe2\x80\x9e i22 4 12 \n\nThe produce of the space, ditto - 2.3-^1^ 5 " \'^ \n\nAt the time the seed is ripe the produce is Grass, \n\n9 oz. The produce per acre - - - \n\n80 dr. of grass weight when dry 24 dr \xe2\x96\xa0> \n\nThe produce of the space ditto - ^TS j \n\nThe weight lost by the produce of one acre in drying \n\n64 dr. of grass afford of nutritive matter 3.1 dr. > \n\nThe produce of the space, ditto - 7.H dr. ^ \n\nThe weight of nutritive matter which is lost by \n\ntaking the crop at the time the grass is in \n\nflower, exceeding half its value - - 188 12 _ 4 \n\nThe proportional value which the grass at the time of flowering bears to \nthat at the time the seed is ripe, is as 4 to 13. \n\nThe latter-math produce is \nGrass, 10 oz. The produce per acre - - 108900 = 6806 4 \n64 dr. of grass afford nutritive matter, 2.1 dr. 3828 8 = 239 4 8 \n\nThe proportional value which the grass of the latter-math bears to that, at \nthe time the seed is ripe, is nearly as 9 to 13. \n\nThe smallness of the produce of this grass renders it improper for the pAr- \npose of hay ; but its early growth, and the superior quantity of nutritive mat- \nter which the latter-math affords, compared with the quantity afforded by \nthe grass at the time of flowering, causes it to rank high as a pasture grass, \non such soils as are well fitted for its growth ; such are peat-bogs, and lands \nthat are deep and moist. \nII. Hokvs odoratus. Host. G. A. Growing in wooils. Sweet-scented soft \n\ngrass Nat of Germany. Flo Ger. \xe2\x80\x94 H borealis. Growing in moist meadows. \n\nAt the time of flowering, the produce from a rich and sandy loam is \n\nGrass, 14 oz. The produce per acre ... \n80 dr. of grass weigh when dry - 20.2 dr. f \nThe produce of the space, ditto - 57.1 y > \nThe weight lost by the produce of one acre in drying \n\n\xe2\x80\xa2 The weight is avoirdupois ; lbs. pounds, or. ounces, dr. drachms. The \nweights not named are, quarters of drachms, and fractions of drachms ; tlius \n7.1 V mieaiis 7 drachms 1 qvrarter of a drachm and i of a quarter. \n\n\n\n98010 = 6125 10 \n\n\n\n\n\n29403 = 1837 11 \n\n\n\n\n\n= 4287 15 \n\n\n\n\n\n4977 10 = 311 1 \n\n\n1 \n\n\n\noz. \n152460 \n\n\nor lbs. per acre. \n= 95 J8 12 \n\n\n39067 14 \n\n\n= 2441 11 14 \n\n\n. \n\n\n7087 2 \n\n\n\nv., \n\n10124 13 \n\n\nor (hs. per acre \n=. 610 15 6 \n\n\n35600 = \n152460 \n\n35732 13 \n\n\n= 27225 \n\n<= 9528 12 \n\n17696 4 \n\n= 2233 4 1.1 \n\n\n\nAPPENDIX. >i59 \n\n\n\n^4 Jr. of grass afford of nutritive matter 4.1 dr. 7 \nThe produce of the space, ditto 14.3^ > \n\nAt the- time the seed is ripe the produce is \nGrass, 40 oz. Ti>c j.rodiice per acre - - *. \n:64idr ofgrusSj .. ngh when dry - 28 rfr. > \n\nTlie produce of the space, ditto - 224 dr. $ \nThe weightiest uytlie produce of one acre in drying \n64 dr. of grass afford nutritive matter 5.1 dr. 1 \nThe produce of the spuce, ditto - 52.2 dr. 3 \nThe weight of nutritive matter wiiich is lost by \n\ntaking the crop at the time tlie grass is in flower, \n\nbeing more than half of its value 1600 8 10 \n\nThe proportional value which the grass at the time of flowering beai-s to \nthat at the time the seed is ripe is as 17 to 21. \n\nThe produce of la\\ter-malh is Grass, 25 oz. The \n\nproduce per acre 272250 =. 17015 10 \n\n64</r. of grass afford of nutritive matter 4.1 (/r. 18079 1= 1129 15 I \n\nThe grass of tlie latter-math crop, and of the crop at the time of flowering, \ntaking the whole quantity, and their relative proportions of nutritive matter, \nare in value nearly as 6 to lU ; the value of the grass at tlie time the seed is \nripe, e-xceeds that of tlie latter-math, in proportion as 21 to 17. \n\nThough this is one ot the earliest of tlie flowering grasses, it is tender, and \nthe produce in the spring is inconsiderable. If however, the quantity of nu- \ntritive matter which it affords, be compared with that of any of those species \nwhich flower nearly at the same time, it will be found greatly superior. It \nseijds forth but a small number of flower stalks, which are of a slender structure \ncompared to the size of the leaves. This will accoiiut in a great measure for \nthe equal quantities of nutritive matter afforded by tiie grass at the time of \nflowering, and the latter-math. \n\nIII. Cynosurus cxrulous. Eng;! Rot. 1613. Host. G. A. 2. t. 98. \nBlue more-grass. Nat. of Britain. Sesleria caerulea. \n\nAt the time the seed is ripe the produce from a light sandy soil is \n\noz. ir. lbs. per acrCi \n\nGrass, 10 oz. The produce per acre - - 108900 = 6806 4 \n64 dr. of grass afford of nutritive matter 3.3 </r. 6380 13= 398 12 13 \n\nThe produce of this grass is greater than its appearance would denote ; the \nleaves seldom attain to more than four or five inches in length, and the flower \nstalks seldom arise to moi\'e. Its growth is not rapid after being cropped, nor \ndoes it seem to withstand the effects of frost, which if it happen to be \nsevere and early in the spring, checks it so much as to prevent it from flower- \ning for that season ; otherwise the quantity of nutritive matter which the \ngrass affords (for the straws are very inconsiderable,) would rank it as a va- \nluable grass for permanent pasture. \n\nIV. Jilopecurus pratends: Curt. Lond. Alo. myosuroides, \nMeadow fox-tail- grsas. Nat. of Britain. Eng. Bot. 848. \n\nAt the time of flowering, the produce from the cl^ey loam is \n\nGrass, 30 oz. The produce per acre - - - \n80 dr. of grass weigh when dry - 24 dr. "> \n\nThe produce of the space, ditto - 336 dr. 3 \nThe weig\'it lost by the produce of one acre in drying \n64 dr. of grass afford of nutritive matter 1 2 dr. ) \nThe produce of the space ditto - 11.1 dr,^ \n\nThe produce from :i sandy loam is \nGrass, 12 oz 8 dr. The produce per aore \n80 dr of grass weigh when dry 24 dr.") \n\nThe produce of tlie space, ditto 60 dr. ^ \n\n60 dr. of grass afford of nutritive matter 1 dr. 5 \nThe produce of the space, ditto 3.0i 5 \n\n\n\noz. \n326700 \n\n\nor lbs. per acre \n= 20418 12 \n\n\n93010 \n\n\n= 1256 61 \n\n\n\n\n\n\n\n14293 2 \n\n\n\n\n\n7657 \n\n\n= 478 9 \n\n\n\n\n\n136125 \n\n\n= 8517 13 \n\n\n\n\n\n40837 \n\n\n9 - 2552 5 \n\n\n8 \n\n\n2126 \n\n\n15 ^ 132 H \n\n\n1-5 \n\n\n\n12931 \n\n\nu \n\n\n\n\n\n5819 \n\n\n5 \n\n\n2 \n\n\n7111 \n\n\n8 14 \n\n\n461 \n\n\n\n\n\n4 \n\n\n\n26\xc2\xa9 AFl\xc2\xbbliN131X. \n\nAt the time the seed is ripe, the produce from the clayey loam is \n\nox. or lbs. per acre \n\nGrass, 19 ox. The produce per acre - - 2G6910 \n\n80 dr. of grass wcigli wlien dry 36 dr. \\ o-^.^n \n\nThe produce of tlie space, ditto 136 3;^ 3 y-3l\\J9 8 \n\nThe welglu lost by the produce of one acre in drying \n\n64. f/)\\ of g-russ afford of nutritive matter 2.1 <//\xe2\x80\xa2.> \xc2\xbb.^_^ . \n\nThe produce of the space, ditto 9.975 $ \n\nThe weiglit of nutritive matter which is lost by \n\nleaving the crop till the seed be ripe, being \n\none twenty-fifth part of its value - If 8 11 \n\nThe proportional value whicli the grass, at the time of flowering, bears to \nthat at the time the seed is ripe, is as 6 to 9. \n\nThe latter-math profluce, from the clay loam is \nGrass, 12 02. \'[\'he produce per acre - - 130680 = 8167 8 \n\n64 </)\xe2\x80\xa2. of grass afford of nutaitive matter 2dr.\\ ,^\xe2\x80\x9e\xe2\x80\x9e ,^ ^ \n\nThe produce of the space, ditto 6 dr. $ ^"""^ ^^ = -^^^ ^ ^^ \n\nThe proportional value which tlie wliole of the latter-math crop bears to that \n\nat the time the seed is ripe, is as 5 to 9, and to that at the time of flowering, \n\nproportionably as 13 to 24. \n\nThe above statement clearly shews that tliere is nearly three-fourths of pro- \nduce greater from a clayey loam than from a sandy soil, and the grass from \nthe latter is comparatively of less value, in proportion as 4 to 6. The straws \nproduced by the sandy soil are deficient in number, and in every respect less \nthan those from the clayey loam : which will account for the unequal quantities \nof nutritive matter afforded by them ; but the proportional value in which \nthe grass of the latter-math exceeds that of the crop at the time of flowering, \nis as 4 to 3 : a difference whicii appears extraordinary, when the quantity of \nflower-stalks which are in the grass at tlie time of flowering is considered. In \nthe Anthoxanthum odoratum the proportional difference between the grass of \nthese crops is still greater, nearly as 4 to 9 ; in the poa pratensis they are \nequal ; but in all the latter flowering grasses experimented upon, the flower- \ning straws of which resemble those of the Alopeciirus pratensis or Anthoxanthum \nodoratum, the greater proportional value is always on the contrary found in \nthe grass of the flowering crop. Whatever the cause may be, it is evident \nthat the loss sustained by taking the crops of these grasses at the time of \nflowering is considerable. \n\nV. Alopecurns alfnnus. Engl. Bot. 1126. \nAlpine fox-tail grass. Nat of Scotland. \n\nAt the time of flowering, the produce from a sandy loam with a small por- \ntion of manure, is \n\noz. or lbs. per acre \n\nGrass, 8 oz. The produce per acre - - 87120 -= 5445 5 \n\n60 dr. of grass weigh when dry 16 dr. -) \xe2\x80\x9eo\xe2\x80\x9e.,\xe2\x80\x9e ^ _ - . ,\xe2\x80\x9e \xe2\x80\x9e \n\nThe produce of the space, ditto 34j-|5 ^^^^ 0-1452 \n\nThe weight lost by the produce of one acre in drying 3993 5 \n\n64rfr. of grass afford of nutritive matter 1 dr.\\ ,o^, . qk ^ a \n\nThe produce of the space, ditto 2 dr.^ ^^^^ * == \xc2\xbb5 1 4 \n\nVI. Poa alpina. Engl. Bot. 1003. Flo. Dan. 107, \nAlpine meadow grass, Nat. of Scotland. \n\nAt the time of flowering, the produce from a light sandy loam, is \n\nOS. or lbs. per acre \n\nGrass, 8 oz. The produce per acre 87120 = 5445 \n\n64 dr of grass afford of nutritive matter 1.2 dr. 2041 14 = 127 9 14 \n\nVII. Avena pubeseens. Engl. Bot. 1640. Host. G. A. 2, t. 50. \nDowny oat grass. Nat. of Britain. \n\n\n\nAPPENDIX. ^t)t \n\nAt the time of flowering, the produce from a rich sandy soil is \n\noz. lbs. per acre \n\nGrass, 23 oz. The produce per acre - - 250470 = 15654 6 \n80 f/r.ofgrass weigh when dry - SO t/r. > =. s\xc2\xab70 6 A \n\nThe produce ofthe space, ditto - 138</r.5 ^^^-^ U = 5870 4 \n\nThe weight lost by the produce of one acre in \n\n\xe2\x96\xa0 drying - - 9783 15 12 \n\n64 dr. of grass afford of nutritive matter 1.2 rf\'\'- } ^ \n\nThe produce of the space, ditto - 8.2,^5 ^^^^ ^= ^^^ ^^ ^ \n\nAt the time the seed is ripe, the produce is \nGrass, 10 oz. Tlie produce per acre - - 108900 = 6806 4 \n. 80 </r. of grass weigh when dry - 16 dr.~i o,,oa n i^c, a r, \n\nTlie produce ofthe space, ditlo - 32 dr. $ 21780 = lo61 4 \n\nThe weight lost by the produce of one acre in \n\ndrying 5445 \n\n64 Jr. of grass afford of nutritive matter 2 dr.") 3403 2 = 212 11 \nTlie produce of the space, ditto 5 dr. $ "^ \n\nThe weiglit of nutritive matter which is lost by leaving the crop \n\ntill the Si ed be ripe, being more than half of its value - 154 6 3 \n\nThe proportional value which the grass, at the time of flowering, bears to that \nat the time the seed is ripe, is as 6 to 8. \n\nThe produce of latter-math is \nGrass, 10 oz. The produce per acre - - 108900 = 6806 4 \n64 </\xc2\xbb\xe2\x80\xa2. of grass afford of nutritive matter 2 dr. 3403 2 = 212 11 \n\nThe proportional value which the grass, at the time of flowering, bears to \nthat of the latter-math, is as 6 to 8. The grass of tlie seed-crop, and that of \nthe latter-math, are of equal value. \n\nThe downy hairs which cover the surface of the leaves of this grass, when \ngrowing on poor light soils, almost entirely disappear when it is cultiva- \nted on a richer soil. It possesses several good qualities which recommend it \nto particidar notice ; it is hardy, early, and more productive than many otliers \nwhich affect similar soils and situations. Its growth, after being cropped, is \ntolerably rapid, although it does not attain to a great length if left growing ; \nlike the Poa pratensis, it sends forth flower stalks but once in a season, and it \nappears well calculated for permanent pasture on rich light soils. \n\n\n\nVni. Poa pratensis. Curt. I^nd. Engl. Bot. 1073. \n\nSmooth stalked meadow grass. Nat. of Britain. \n\nAt the time of flov/ering, the produce from a mixture of bog-earth and \nclay, is \n\noz. or lbs. per acre \n\nGrass, 15 oz. The produce per acre - - 163350 = 10209 6 \n80 </r. of grass weigh when dry - 22.2 dr.\\ ..g \n\nThe produce of the space, ditto - 67.2 dr. ^ ^ \' \xc2\xb0 -^ \nThe weight lost by the produce of one acre in \n\ndrying 7337 15 13 \n\n64 f/r. of grass afford of nutritive matter 1.3 t/r. 7 ^Acc n o^n ^ \n\nThe produce of the space, ditto - 6 2. J 5 \'^\'^\'\xc2\xb0\xc2\xb0 9 = 279 2 9 \n\nAt the time the seed is ripe the produce is \n\nGrass, 12.8 oz. The produce per acre - 136825 \n\n80 dr. of gcass weigli when dry - 32 dr. 7 ,. , . _ \nThe produce of the space, ditto - 80 dr. $ * \n\nThe weight lost by tlie produce of one acre in drying \n64 dr. of grass afford of nutri\'Tve matter 1.2 <ir. ) \nThe produce of the space, ditto - 4.2 j\\ S \nThe weight of nutritive matter which is lost by leaving the croo \ntill the seed be ripe, being nearly one fourth of its value - \' 79 12 \n\n\n\n== 8507 13 \n\n\n\n\n\n= 3403 2 \n\n\n\n\n\n5104 11 \n\n\n\n\n\n6 = 199 6 \n\n\n\n\n\n\n262 APl\'BNDIX. \n\nThe produce of latter-math is \n\noz. or Iba per acre \n\nGrass, 6 oz. The produce per acre 653-10 \xe2\x84\xa2 4U83 12 \n\n64 \xc2\xbb/r. of grass aHonl of outritiNc matter 1.3 </r. 1786 10 11110 \n\nThr proportioiKil vahie iii which the prass of the latter-math exceeds tliat \nof the flowering\' crop, is as 6 to 7. I\'lie grass of the seed crop and that of \nthe latter matli are of eipiai value \n\nThis jjniss is therefore of least vahic at the time the seed is npc ; a loss of \nmore than one-fourth of the value of the wliole crop is susiainetl if it is not \ncut till that period : the straws are then dry, and tlie root leaves in a ickly \ndecaying state ; those of the unler-inath, on tlie contrary, are luxuriant and \nhealthy. This species sends Ibrth flower-staiks but once in a season, and \nthese being the most valuabh part of tiie plant for ilie purpose of hay ; it \nwill, from tiiis circumstance, ahd the superior value of tlu- grass of the latter- \nmatli, compared to tliat of the seed crop, appear well adapted for permanent \npasture. \n\nIX. Poa ccentlea. \xe2\x80\x94 \\sLr. Poa pratensis. Engl. Bot. 1004. Poa subcxrulea. \n\nShort blueish meadow grass. Nat. of Britain. H. Kew. 1 \xe2\x80\x94 155. Poa \nhumilis. \n\nAt the time of flowering, the produce from a soil of the like nature as the \npreceding, is \n\nGrass, 11 oz. Tiie produce per acre \n64 dr. of grass aiford of nutritive matter 2 dr. \') \nThe produce of the sjiace, ditto 5.2 dr. 5 \n\n80 dr. of grass weigh wiieii ilry 24 <\'\'\xe2\x80\xa2 ) \n\nThe protluce of the space, ditto 52.3 jg 5 \n\nThe weight lost by the produce of one acre in \n\ndrying - - 5240 13 \n\nIf the produce of this variety be compared with that of the preceding one, \nit will be found less ; nor does it seem to possess any superior excellence. The \nsuperior nutritive power does not make up for tlie deficiency of produce by \n80 lbs. of nutritive matter per acre. \n\nX. Frstuca hordifurinis. Poa hordiformis. H. Cant. \nBarley -like fescue grass. Nat. of Hungary. \n\nAt the time of flowering, the produce from a sandy soil, with manure is \n\noz or lbs. per acre \n\nGrass, 20 oz The produce per acre - - 217800 0\xe2\x80\x9413612 8 \n\n80 rfr.ofgt-ass weigh when dry - 24dr.^ 65340 =. 4083 12 \nThe produce ot tlie space, ditto - Vo dr. y \nThe weight lost by the produce of one acre in \n\ndrying . 9528 12 \n\n\xe2\x80\xa2 64 </r. of grass aflbrd of nutritive matter 2 1 rfr. ^ -^.^ ^ .-o q . \n\nThe produce of the space, ditto 11.1 </r. 5 = 4/0 1/0 \n\nThis is rather an early grass, though later than any of the preceding\' spe- \ncies ; its foliage is very fine, resembling the P. ditriiisciild, to which it seems \nnearly allied, dilfering only in the length of the awns, and the glaucous colour \nof the whole plant The consiilerable produce it alVords, and the nutritive \npowers it appears to possess, joined to its early growth, are qualities which \nstrongly recommend it to further trial. \n\nXI. Poatrivialis. CUirt. Lond. Kngl B \'t. 1072. Host. G. A. 2. t. 62. \nRoughish meadow grass. Nat. of Britain. \n\n\n\n11970 \n\n\nor lbs. per acre \n^ 7486 14 \n\n\n3743 \n\n\n7 = 233 15 \n\n\n35037 \n\n\n=. 2246 1 \n\n\n\nAPFENDIX. \n\n\n\n2m \n\n\n\nAt the time of flowering, the produce from a liglit brown loam, with ma- \n\n\n\nnure, IS \n\n\n\n119790 \n35937 \n\n\n\nor Iba. per acre \n- 7486 14 \n\n\n\n\n\n\n\n374-3 7 \n\n125235 \n\n56355 12 \n\n5381 3 \n\n\n\n2246 1 \n\n5240 13 \n233 15 \n\n7827 3 \n3522 3 \n\n4304 15 \n336 5 \n\n\n\nGrass, 1 1 oz. The produce per acre \n80 dv. of grass weigh wlicn dry - 24 fir. ) \n\nThe produce of tlie fTpace, ditto - ^\'^luS \n\nThe weight lost by the produce of one acre in \n\ndryini^ \n\n64 dr. of grass afTonl of nutritive matter 2 dr. } \nThr produce of llu* space, ditto - 5.2 dr. 5 \n\nAt the time tiic seed is ripe the produce is \nGrass, 11.8 oz. The produce per acre \n80 dr. of grass weigh when dry - 36 dr- f \n\nThe prochice of tlie spac<\', ditto - 82.3-ig^3 \nThe weight h)3t by the produce of one acre in \n\ndrying ..._... \n64 dr. of grass afford of niitritire matter S-S^i ^ \nThe produce of lh(^ space, ditto - 7.3j 5 \n\nThe weigiit of nutritive niatttr which is h)st by taking tiie crop at \n\nthe time of flowering, exceeihiig me fourth of its vaKie - 102 5 \n\nThe proportional value in which the grass of the seed crop exceeds that at \nthe time of flowering is as 8 to 11. \n\n\n\nThe produce of latter math is \nGrass, 7 oz. The pr-.duce per acre - - 76230 == 4764 6 \n\n64 dr of grass afliird of nutritive matter 3 dr. 3573 4 \xe2\x96\xa0= 223 5 4 \n\nThe proportional value by which the grass of the latter-math exceeds that \nof thi flowering crop is as 8 to 12, and that of the seed crop as 11 to 12. \n\nMere then is a satisfactory proof of the superior value of the crop at the \ntime the seed is ripe, and of the consequent loss sustained by taking it when \nin flow* r ; tiie produce of each crop being nearly ecpial. The deficiency of \nhay in the flowering crop, in proportion to that of tl\xc2\xbbe seed crop, is very stri- \nking Its superior produce, the highly nutritive powers which the grass seems \nto possess, and the season in which it arrives at perfection, are merits which \ndistuiguish ii xs one of tlie most valuable of those grasses, which affect moist \nrich sods, and slieltered situatious ; but on dry exposed situations it is altoge- \nther inconsiderable ; it yearly diminishes, and ultimately dies off, not unfre- \nquently in the space of four or five years. \n\n\n\nXII. \n\n\n\nFestuca glavca. Curtis. \n\nGlaucous fescue gra-.s. Nat. of Britain \n\n\n\n152460 \n60984 \n\n\n\nor Ibn. per acre \n=. 9528 12 \n\n\n\n== 3811 8 \n\n\n\n5.1 rf)-. 5 \n\n\n\n32 *\xe2\x80\xa2> \n89.2| 5 \n\n\n\n2573 4 \n\n\n\nGrass, 14 oz. The produce per acre \n80 dr. of grass w \'i^h when dry 32 dr. \nThe produce of t \' space, ditto 89.2t^.\'3j \n\nThe weight lost by die produce of one acre in \n\ndrying \n\n64 dr. of gra.ss afford of imtritive matter 1.2 dr. \'} \n\nThe produce of the space, ditto \n\nAt the time of flowering the produce is \n\nGrass, 14 oz. The produce per acre \n\n80 dr. of grass weigh when dry \n\nThe produce of the space, ditto \n\nThe weight lost by the produce^JP\' one acre in \n\ndrying \n\n64 dr of grass afford of nutritive matter 3 dr. \nThe produce of the space, ditto - 10.2 dr \nThe weight of nutritive matter which is lost by leaving the crop \n\ntill the seed be ripe, being half of the value of the crop - 223 \n\n\n\n152460 \n60984 \n\n\n\n7146 9 - \n\n\n\n5717 4 \n223 5 \n\n9528 12 \n4811 8 \n\n5717 4 \n446 10 \n\n\n\n264 \xe2\x80\xa2 APPENDIX. \n\nThe propoilionul value by which the grass, at the time of flowering exceed? \nthat at the time the seed is ripe, is as 6*0 12. ^ \n\nThe proportional difference in the value of the flowering and seed crops of \nthis grass is directly the reverse of that of the preceding species, and affords \nanother strong proof of the value of the straws in grass which is intended for \nhay. The straws, at the time of flowering, are of a very succulent nature ; \nbut from that period till the seed be perfected, they gradually become dry and \nwiry. Nor does the root leaves sensibly increase in number or in size, but a \ntotal suspension of increase appears in every part of the plant, the roots and \nseed vessels excepted. The straws of the Poa trixrialis are, on the contrary, \nat the time of flowering, weak and tender ; but as they advance towards the \nperiod of ripening the seed, they become firm and succulent ; after that peri- \nod, however, they rapidly dry up and appear little better than a mere dead \nsubstance. \n\nXIII. Festuca glabra. Wither. B. 2. P. 154. \nSmooth fescue grass. Nat. of Scotland. \n\nAt the time of flowering, the produce from a clayey loam with manure is \n\nor. or lbs. per acre \n\nGrass, 21 or. The produce per acre - 228690 0=14293 \n\n80 tfr of gi-ass weigh when diy ^2 *?\xc2\xbb-. ^ \xe2\x80\x9e. y,g -^^ S7\\7 4 \n\nThe produce of the space, ditto 134.1i%,t5 ^^*\'\xc2\xb0 v-=:}fu 4 u \n\nThe weight lost by the produce of one acre in \n\ndrying - - 8576 14 \n\n64 dr. of gi-ass afft)rd of nutritive matter 2 dr. 7 "-iaa t\\ jlaf. in n \n\nThe produce of the space, ditto 10.2 dr. 5 ^ 140 U = 440 lu u \n\nAt the time the seed is ripe the produce is \nGnss. 14 oz The produce per acre - - 152460 <= 9521 12 \n80 rfr.ofgrass weigh when dry . 32 Jn^ g^gg q == 3811 8 \nThe producp of the space, ditto 89.2y 3 \n\nThe weight lost by the produce of one acre in \n\ndrying 5717 4 \n\n64 dr. of grass afford of nutritive matter 1 1 <^\'\'\' ^ ocr 1 1 \xe2\x80\xa2\xe2\x80\xa2 t o<: in \nThe produce of the space, ditto - 4.1tV5 ^^\' \' ^^ =" ^^^ 1 ii \nThe weight of nutritive matter which is lost by leaving the crop \n\ntill the seed be ripe, exceeding half of its value - - 260 9 \n\nThe proportional value which the grass at the time the seed is ripe, bears \nto that of the crop at the time of flowering, is as 5 to 8. \n\nThe produce of latter-math is \nGrass, 9 oz. The produce per acre \n6t dr. of gi\'ass afford of nutritive matter 2 ^r \'^ \nThe produce of the space, ditto - l.O^Jr. 3 \n\nThe proportior.al value which the grass of the latter-math be\xc2\xabrs to that of \nthe crop at the time of flowering, is as 2 to 8, and to that of the crop, at \nthe time tlie seed is ripe, is as 2 to 5. \n\nThe general appearance of t!\xc2\xbbis grass is very slinihrr to that of the Featma \nduriiMcafa : it is however, specifically dift\'erent, and inferior in many respects, \nwhich will be manifest on comparing their sevcnil prodiico with each other . \nbut if it be compared with some others, now under (jenct-a! ctillivation, the re- \nsult is much in its favour, the soil which it affects being duly attended to. The \nAnthoxunthum odovatum being taken as an example, it. appears that \n\nIds. per acre \nFestuca glabra, affords of nutritive matter \n\nFrom the crop at the time of fioweriivg - - - 446. > ,^^ \n\n\n\noz. \n\n\n\n\nor \n\n\nlbs. per acre \n\n\n98010 \n\n\n\n\n\n^ \n\n\n6125 \n\n\n10 \n\n\n\n\n\n765 \n\n\nU \n\n\n= \n\n\n47 \n\n\n1.3 \n\n\n\n\n\n\nAPPENDIX. \n\n\n\n265 \n\n\n\nAnthoxanthum odoratum, \n\n\n\n?:^ \n\n\n\nAt the time of flowering, ditto - - - - - 122. \nAt the time the seed is ripe, ditto .... 31 \n\nThe weight of nutritive matter, which is afforded by the produce \nof one acre of the Festuca glabra exceeding tliat of the Anthox- \nanthum odoratum, in proportion nearly as 6 to 9, \n\n\n\nlbs. per acre \n\n\n\n433. \n\n\n\n199. \n\n\n\nXIV. \n\n\n\nEesUica rubra. Wither. B. 2. P. 153. \nPurple fescue grass.Nat. of Britain. \n\n\n\nAt the time of flowering, the produce from alight sandy soil, is \n\n\n\noz. \n163350 \n\n\n\n\n56923 12 \n\n\n\nor tbs. per acre \n= 102U9 6 \n\n\n\n3557 11 \n\n\n\n3828 8 \n\n\n\n6651 U \n239 4 \n\n\n\n174240 \nr8408 \n\n\n\n=10890 \n= 4900 \n\n\n\n\n8 \n\n\n\n5445 \n\n\n\n5989 \n\n340 \n\n\n\n8 \n\n\n\nGrass, 15 oz. The produce per acre \n80 dr. of grass weigh when dry - 34 dr. ") \n\nThe produce of the space, ditto - 102 dr. ^ \nThe weight lost by the produce of one acre in \n\ndrying ....... \n\n64 dr. of grass afford of luitritive matter 1.2 dr. \\ \nThe produce of the space, ditto - 22^ dr. \n\nAt the time the seed is ripe the produce is \nGrass, 16 or The produce per acre \n80 dr. of grass vVeigh when dry - 36 dr. ^ ^ \n\nThe produce of the space, ditto 115 3 //,.. 3 \n\nThe weight lost by the produce of one acre in \n\ndrying \n\n64 dr. of grass afford of nutritive matter 2 dr. , \nThe produce of the space, ditto - 8 dr. \'. \n\nThe weight of nutritive matter which is lost by taking the crop \n\nwhen the grass is in flower, being nearly one-third part of its \n\nvalue - 101 \n\nThe proportional value which the grass, at the time of flowering, bears to \nthat at the time the seed is ripe, is as 6 to 8. \n\nThis species is smaller in every respect than the preceding. The leaves \nare seldom more than from three to four inches in length ; it affects a soil si- \nmilar to that favourable to the growth of the Festuca ovina, for which it would \nbe a profitable substitute, as will clearly appear on a comparison of their pro- \nduce with each other \n\nThe produce of latter-math is \nGrass, 5 oz. The produce per acre - . 54450 = 3403 2 \n\n64 t/r. of grass afford of nutritive matter 1.2 dr. 1276 2= 79 12 \n\nThe proportional value which the grass of the latter-math bears to that at \nthe time the seed is ripe is as 6 to 8, and is of equal value with the gi-ass at the \ntime of flowering. \n\nXV. Festuca ovina. Engl.fBot. 585. Wither. B. 2. P. 152. \nSheep\'s fescue grass. Nat. of Britain. \n\n\n\n8 \n\n\n\nAt the time the seed is ripe the produce is \n\n\n\nGrass, 8 oz. The produce per acre \n64 dr. of grass afford of nutritive matter \nThe produce of the space, ditto \nThe produce of latter-math is \nGrass, 5 oz. The produce per acre \n64 dr. of grass afford of nutritive matter \n\n\n\n1.2 Jr.? \n3dr.S \n\n\n\n1.1 dr. \n\n\n\n87120 \n2031 14 \n\n\n\nor lbs. per acre \n\n\n\n\n= 5445 \n= 127 \n\n\n\n9 \n\n\n\n54450 \n1063 \n\n\n\n= 3403 \n\n\n\n7 = \n\n\n\n66 \n\n\n\nThe dry weight of this species was not ascertained, because the smallness \nof the produce renders it entirely unfit for hay. If the nutritive powers of this \nspecies be compared with those of the preceding, the inferiority will appear \nthus : \n\nl1 \n\n\n\n1.21 \n\n1.1 5 \n\n\n\n266 APPENDIX. \n\nFestuca ovina, (as above) ufToi\'ds of nutritive matter \nDitto ditto ditto \n\nFestuca nibra ditto ditto ~ < "12 \n\nDitto > ditto ditto 1.2 5 \n\nThe coniijarative degree of nourishment which the grass of the Festuca ru- \nbra affords, exceeds therefore that aflorded by the F. ovina, in proportion as \n11 to 14. \n\n^ From the trial that is here detailed, it does not seem to po.ssess the nutri- \ntive powers generally ascribed to it ; it has the advantage of a fine foliage, and \nmay, therefore, very probably be better adapted to the masticating organs of \nsheep, than the larger gi-asses, whose nutritive powers are shewn to be great- \ner : hence on situations where it naturally gi\'ows, and as pasture for sheep, it \nmay be inferior to few others. It possesses natural characters very distinct \nfrom F. rubra. \n\nXVI. Briza media. Engl. Bot. 340. Host. G. A. 2. t. 29. \nCommon quacking-grass. Nat. of Britain. \n\nAt tlie time of flowering, the produce from a rich brown loam, is \n\noz. or lbs. per acre \nGrass, 14 oz. The produce per acre - - 152460 = 9528 12 \n80 f/r. of grass weigh when dry - 26 rfr. ^ ..oeAo o nnac ti a \n\nThe produce ofthe space, ditto 72.2-^^^,-. 5 *^^*^ 8=3096 13 8 \n\nThe weight lost by the produce of one acre in \n\ndrying - ". - - 6431 14 8 \n\n64 </r. of grass aflbrd of nutritive matter 2.3 t/c.^ .^.^ \xe2\x80\x9e .\xe2\x80\x9e\xe2\x80\x9e _ ^ \n\nThe produce of the space, ditto - 9.2^*^5 ^^^^ U = 4Uy 7 U \n\nAt the time the seed is ripe the produce is \nGrass, 14 oz. The produce per acre - - 152460 = 9528 12 \n80 Jr.ofg.-ass weigh when dry - 28. /r. 7 53362 = 3335 1 \n\nThe produce of the space, ditto - 78.1|. 3 \n\nThe weight lost by the produce of one acre in \n\ndrying - 6183 11 \n\n64 </r. of grass afford of nutritive matter 3.1 dr.\') "jfrn \\ = 483 14 1 \n\nThe produce of the space, ditto - 11.1^) \n\nThe weight of nutritive matter which is lost by taking the crop at \n\nthe time of Howering, being nearly one-fourth part of its value 109 1 \n\nThe proportional value wliich the grass at the time of flowering, bears to \ntliat at tlie time the seed is ripe, is as 11 to 13. \n\nThe latter math produce is \n\noz. or Ihs. per acre \n\nGrass, 12 oz. The produce per acre - - 130680 = 8167 8 \n64 <//\xe2\x80\xa2. of grass afford of MU\'ritivi- niiiltcr Idr. 4083 12== 255 3 12 \n\nThe pro])ortional value in which the grass at the time of flowering, exceeds \nthat of the latter math, is as 8 to 11; and thelatter-math stands to that at \ntlie time the seed is ripe in proportion as 8 to 13. \n\nThe merits of this grass seem to demand notice ; its nutritive powers are \nconsiderable, and its produce large when cbmpai-ed with others which affect \na similar soil. \n\nXVII. Bactulis glomerala. Engl. Bot. ?35. Fl. Dan. 743. \nRound-headed cocks-foot grass. Nat. of Britain. Wither. B. 2. E. 149. \n\nAt the time of flowering, the j)roduce from a rich sandy loam is \n\noz. lbs. per acre \n\nGrass, 41 ox. The produce per acre - - 446490 0=27905 10 \n\n\n\nAPPENDIX. \n\n\n\n267 \n\n\n\n\'r.S \n\n\n\n189758 4 \n\n\n\nor lbs. per acre \n=11859 14 4 \n\n\n\n17424 \n\n\n\n16045 11 \n= 1089 \n\n\n\n424710 \n212355 \n\n\n\n= 26544 6 \n\n\n\n\n\n\n\n= 13272 \n13272 \n\n\n\n23SJ26 5 = 1451 10 \n\n\n\n80 dr. of grass weigh when dry - 34 dr. \n\nThe produce of the space, ditto 278^^ dr, \n\nThe weight lost by the produce of one acre in \n\ndrying \n\n64 dr. of grass afford of nutritive matter 2.2 dr. \') \nThe produce of the space, ditto - 25.2^\' > \n\nAt the time the seed is ripe the produce is \nGrass, 39 oz. The produce per aci"e \n80 dr. of grass weigh when dry - 40 dr. ^ \n\nThe produce of the space, ditto - 312 dr. 3 \n\nThe weight lost by the produce of one acre \n64 dr. of grass afibrd of nutritiv e matter 3.2 dr. \') \nThe produce of the space, ditto - 34.0^ 3 \nThe weight of nutritive matter which is gained by leaving the crop \n\ntill the seed be ripe, being more than one-third part of its value, is 362 10 5 \n\nThe proportional value which the grass at the time of flowering, bears to \nthat at the time the seed is ripe, is as 5 to 7, nearly. \n\nThe produce of the latter-math is \nGrass, 17 oz. 8 ./r. The produce per acre - 190575 0=11910 15 \n64 Jr. of grass afford of nutritive matter 1.2 dr. 4466 9 = 281 10 9 \n\nThe proportional value which the grass of the latter-math bears to that at \nthe time of flowering, is as 6 to 10 ; and to that at the time the seed is ripe, \nas 6 to 14. 64. dr. of the\' straws at the time of flowering afford of nutritive \nmatter 1.2 dr. The leaves or latter-math, and the straws simply, are there- \nfore of equal pnoportional value; a circumstance which will point out this \ngrass to be more valuable for permanent pasture than for hay. The above de- \ntails prove, that a loss of nearly one-third of the value of the crop is sustained, \nif it is left till the period when the seed is ripe, though the proportional value \nof the grass at that time is greater, i. e. as 7 to 5. The produce does not in- \ncrease if the grass is left growing after the period of flowering, but uniformly \ndecreases ; and the loss of latter-math, which, (from the rapid growth of the \nfoliage after the grass is cropped) is very considerable. These circumstances \npoint out the necessity of keeping this grass closely cropped, either with the \nscythe or cattle, to reap the full benefit of its great merits. \n\nXVIII. Bromus tectonm. Host. G. A. 1, t. 15. \n\nNodding pannicled brome-grass. Nat. of Europe Litroduced 1776. \nH. K. 1. 168. \n\n\n\nAt the time of flowering, the produce from a light sandy soil, is \n\nor lbs. per acre \nGrass, 11 oz. The produce per acre \n80 dr. of grass weigh when dry \xe2\x80\xa2 42 dr- ^ \n\nThe produce of the space, ditto - 92.1^3 \n\nTlie weight lost by the produce of one acre in \n\ndrying \n\n\n\noz. \n119790 = 7486 14 \n\n62889 12 == 3930 9 12- \n\n\n\n3556 4 4 \n\n\n\n64 dr. of grass afford of nutritive matter \nThe produce of the space, ditto \n\n\n\n3 dr. I \n.1 dr. 3 \n\n\n\n5615 2 \n\n\n\n350 15 2 \n\n\n\nThis species being strictly annual, affords no latter-math, which renders it \ncomparatively of little value. ^ \n\nZIX. Festuca cambrica. Hudson. W B. 2. P. 155. Nat. of Britain \n\nAt the time of flowering, the produce from a light sandy soil, is \n\noz. or lbs. per acrfe \n\nGrass, 10 05, The produce per acre - - 108900 ..--6806 4 \n\n\n\n268 APPENDIX. \n\noz. or IBe. per acre \n\n80 r/r. of grass weigh when dry - 34 .A-. ? ^^^^^ 8=2892 10 8 \n\n1 he produce ot the space, ditto - 68 dr. > .v \n\nThe weight lost by the produce of one acre in \n\ndr\\ing - 3913 9 8 \n\n64 dr. of grass afford of nutritive matter 2.1 dr. \') \'laoa a _ 239 4 8 \nTlie produce of the space, ditto - 5.2^ 5 \'" \n\nThis species is nearly allied to the Festuca ovina, from which it differs little, \nexcept that it is larger in every respect. The produce, and the nutritive mat- \nter which it affords, will be found superior to those given by the F. ovi7ia, if \nthey are brought into comparison. \n\nXX. Brovms dlandnis. Curt. Lond. Engl. Bot. 1006. Nat. of Britain. \n\nAt the time the grass is ripe flower, the produce from a rich brown loam, is \nGrass, 30 os. The produce per acre - - 326700 =20418 12 \n80 r/r.ofgrass weigh when dry - 34 Jr.? 138347 8 = 8677 15 \n\nThe produce or the space, ditto ^04 dr. 3 \n\nI\'he weight lost by the produce of one acre in \n\ndrying - 11740 13 \n\n64 </r. of grass afford of nutritive matter 3 f/r. > iroiA \\ oer 9 1 \n\nThe produce of the space, ditto - 22.2 5 1 =\xc2\xbb vo/- ~ 1 \n\nThis species, like the preceding, is strictly annual ; the above is therefore \nthe produce for one year, which, if compared to that of the least productive \nof the perennial grasses, will be found inferior, and it must consequently be rC" \ngarded as unworthy of culture. \n\nXXI. Poa angmtifolia. With. 2. P. 142. \nNarrow-leaved meadow grass. Nat. of Britain. \n\nAt the time of flowering, the produce from a brown loam, is \n\noz. or lbs. per acre \n\nGrass, 27 02. The produce per acre - - 294030 0=18376 14 \n80 f/r. of grass weigh when dry - "* \'^\'\xe2\x80\xa2- ? 104962 12 - 7810 2 12 \n\nThe produce ofthc space, ditto - 183.2| 5 1-*^\xc2\xb0^ ^^ - \'\xc2\xbb^" ^ ^^ \n\nThe weight lost by the produce of one acre in \n\ndrying 10566 11 4 \n\n64 dr. of grass afford of nutritive matter 5 dr. \') ooscfi 11 1 A.\'in \xc2\xab 11 \n\nThe produce ofthe space, ditto - 33.3 5 ^-^\xc2\xbb\xc2\xbbo ^^ = i*ju on \n\nAt the time the seed is ripe, the produce is \n\nGrass, 14 oz. The produce per acre - - 152460 = 9528 12 \n\n80 Jr. of grass weigh when dry - 32 Jr. ? f-r^Qf.. r. oo\xe2\x80\x9e \xe2\x80\x9e -. \n\nThe produce of the space, ditto - 89.2^ 5 ^"^^* = 08U 8 \nThe weight lost by the produce of one acre in \n\ndrying 5717 4 \n\n64 Jr. of grass afford of nutritive matter 5.1 Jr.? lotAC t \xe2\x96\xa0rni fi t \n\nThe produce of the space, ditto - 18.1^ 5 ^"^^^^ / - 7ui o 7 \n\nThe weight of nutritive matter wliich is lost by leaving the crop \n\ntiU the seed be ripe, exceeding one-third part of its value - 649 4 \n\nIn the early growth of the leaves of this species of Poa, there is a striking \nproof that early flowering in grasses is not always connected with the most \nabundant early produce of leaves. In this respect all the species which have \nalready come under examination, are greatly inferior to that now spoken of. \nBefore the middle of April the leaves attain to the length of more than twelve \ninches, and are soft and succulent ; in May, howevei", when the flower-stalks \nmake their appearance, it is subject to the disease termed rust, which af- \nfects the whole plant ; the consequence of which is manifest in the great defi- \nciency of produce in the crop at the time the seed is ripe, being one-half less \nthan at the time of the flowering of the grass. Though this disease begins in \n\n\n\nAPPENDIX. 269 \n\nthe straws, the leaves suftcr most from its effects, being al the time tlie seed \nis ripe completely dried up : the straws, therefore, constitute the principiil \npart of the crop for mowing, and they contain more nutritive matter in propor- \ntion than the leaves. This grass is evidently most valuable for pernjancnt jias- \nture, for which, in consequence of its srpcrior, rapid, and early growtii, and \nthe disease beginning at the straws, nature seems to have designed it. The \n, grasses which approach neaiest to this in respect of early produt:e of leaves, \nare tlie Poa fcrtilis, Dac\'.ijlis glomerata, PIdcum pralenac, Jilofiecunta pralemis, \nJlvena etiator, and Bromus littoreus, all grasses of a coarser kind. \n\nXXII. Avi-iM eliator. Curtis 191. Engl. Bot. 813. \xe2\x80\x94 Holcus avenaceus. \nTall oat -grass. Nat. of Britain. \n\nAt the time tlie seed is ripe, the produce is \n\noz. or Ihs, per acre \n\nGrass,, 24 or. The produce per acre - - ,261360 0=16335 \n8 i *\xe2\x80\xa2. of grass weigh when dry - 28rf,-.> 91475 14 _ 5717 <i 14 \n\nThe produce of the space, ditto 134.13 5 \'dll.lti it - oiu J 14 \n\ne weight lost by the produce of one acre in \n\n\'.niag , - . . . 10617 12 2 \n\n(ir. of grass afford of nutritive matter 1 dr.\') >inpo \xc2\xab<> nee o 10 \n\nThe produce of the space, ditto - 6 Jr. 5 *iJ\xc2\xbbJ l^ - ^55 6 IZ \n\nThe produce of latter-math is. \nGrass, 20 oz. The produce per acre - - 217800 0=13612 8 \n64 dr of grass afford of nutritive matter 1.1 dr. 4ii53 14 = 265 13 14 \n\nThe weight of nutritive matter which is afforded by the crop of \n\nthe latter-math, exceeding that afforded by the grass of the seed \n\ncrop in proportion nearly as 26 to 25. - - - - 10 9 2 \n\nThis grass sends forth flower straws during the whole Season ; the latter- \nmath contains nearly an equal number with the flowering crop. It is subject \nto the rust, but the disease does not make its appearance till after the period \nof flowering; it affects the whole plant, and at the time the seed is npe the \nleaves and straws are withered and dry. This accounts for tlie superior value \nof the latter-math over the seed crop, and points out the propriety of taking \nthe crop when the grass is in flower. \n\nXXIII. Poa eliator. Curtis, 50. \nTall-meadow grass. Nat, of Scotland. \n\nAt the time of flowering, the produce from a rich clayey loam, is \n\nGrass, 18 02. The produce per acre \n80 dr. of grass weigli when dry 28 dr. ") \n\nTlie produce of the space, ditto 100.3 .? ^ \n\n64 dr. of grass afford of nutritive matter 3.2 dr. " \nTlie produce of the space, ditto - 15.3 \n\nThe weight lost by the produce of one acre in \n\ndrying .... .... 36I7 15 3 \n\nThe botanical characters of this g^ass are almost the same as those of thf^ \n^vena eliator, differing in the want of the awns only. It has the essential cha \nracter of the Hold (Florets male, and hermaphrodite. Calyx husks two-valved \nwith two florets) and since the Aveiia eliator is now referred to that ^cw\\^ Ibis \nmay with certainty be considered a variety of it. \n\nXXIV. Fentuca duriusada. Engl. Bot. 470. W. B. 9. P. 153. \nHard fescue grass Nat. of Britain. \n\n\n\noz. \n196020 \n\n\nor lbs. per acre \n=-12251 4 \n\n\n60607 \n\n\n=- 4287 15 \n\n\n10719 \n\n\n13 = 669 15 13 \n\n\n\n270 APPENDIX. \n\nAt the time of flowering, tlie produce from a light sandy loam, is \n\nor. or Ids. per acre \n\nGrass, 27.8 or. The produce per acre - 294030 0=18376 14 \n80 f/;-. of grass weigh when dry - 26 dr.-^ ,\xe2\x80\x9e\xe2\x80\x9e,,\xe2\x80\x9e \n\nThe produce of the space, ditto 194 l| $ ^\'\'^\'^^^ 8 = 8259 9 \nThe weight lost by the produce of one acre in \n\ndrying - . . 10106 4 8 \n\n<J4 ^/r. of grass afford of nutritive matter 3.2 Jr. ^ i/jnro io inri/i m: to \n\nThe produce of the space, ditto 23.2^ 5 ^\xc2\xb0^7y ^^ = ^^^* ^^ ^"^ \n\nAt the time the seed is ripe the produce is \n\nGrass, 23 o:. The produce per acre - - 304920 0=19075 8 \n\n80 if/r. of irrass weitih when dry - 36dr. 1 io-oi.< n o\xc2\xab^-r\xc2\xab: ia n \n,p. f \xc2\xa3. ., *^ , y,: cm o2 c 1\'37214 = 8j75 14 \n\nThe produce ot the sjntcc, ditto \xc2\xab01..Jy3 \n\nThe weight lost by tlie produce of one acre in \n\ndrying ... - 10481 10 \n\n64 Jr. of grass afford of nutritive matter 1.2 Jr.^ .y,^/- \xe2\x80\x9e aac ^n n \n\nThe produce of the space, ditto 10.2 Jr. 5 /^^^ ^= ^"^^ ^^ ^ \n\nThe weight of nutritive matter which is lost by leaving the crop \n\ntill the seed be ripe, exceeding one-half of its value - 558 5 3 \n\nThe proportion.ll value which tlie grass, at the time the seed is ripe, beai\'S to \n\nthat at the time of flowering, is as 6 to 14, nearly. \n\nThe produce of latter-math is, \nGrass, 15 or. The produce per acre - - 163350 =.10209 6 \n64 Jr. of grass afford of nutritive matter 1.1 Jr. 3190 4= 199 6 4 \n\nThe proportional value wliich the grass of the latter-math bears to that at \nthe time of flowering, is as 5 to 14, and to that at the time the seed is ripe, \n5 to 6. \n\nThe above particulars will confirm the favourable opinion which was given \nof this grass when speaking of the Festuca hordifovmis, and F. glabra. Its pro- \nduce in the spring is not very great, but of the finest quality, and at the tim\xc2\xab \nof flowering is considerable. If it be compared with" those affecting similar \nsoils such as Foa pratensis, Festuca ovina, &,c. either considered as a grass for \nhay, or permanent pasture, it will be found of greater \\iJuc. \n\nXXV. Bromns erectus. Engl. Bot. 471. Host. G. A. \nUpright perennial brome glass. Nat. of Britain. \n\nAt the time of flowering, the produce from a rich sandy soil, is \n\noz or lbs. per acre \n\nCrass, 19 or. The produce per acre - - 206910 0=1293114 \n\xc2\xab0 Jr. of grass weigh when dry - ^^ :\';-l 93109 8 = 5819 5 8 \n\nthe produce of tlie space, ditto - 136. oy > \nThe weight lost by the produce of one acre in \n\ndrying - " 7112 8 S \n\nji4 Jr. of grass .-ifl-ord of nutritive matter 2.3 Jr. ^ 8890 10= 555 10 10- \nThe produce of the spiice, ditto - lo.Oj > \n\nXXVI. Milivm efusunu Curt. Lond. Engl. Bot. 1106. \nCommon millet grass. Nat. of Britain \n\nAt the time of flowering, the produce from a light sandy soil, is \n\noz, or llis. per acre \n\ntJrass, 11 or. 8 Jr. The produce per acre - 196020 0=12251 4 \n\n80 Jr. of grass u-eigh when dry ^^Irf^J 7595712=4747 5 li \nThe produce of the space, ditto lll.Sg- y \n\n64 dr. of grass allord of nutritive matter 1.3 Jr. ^ ^r, -q ,^ _ no^ , - j^ \n\nThe produce of the space, ditto 7.3* S ~ \n\n\n\nAPPENDIX. \n\n\n\n271 \n\n\n\n\' This species in its natural state seems confined to woods as its place of \n^jTowth ; but the trial that is here mentioned, confirms the opinion that it will \ngrow and tlirive in open exposed situations. It is remarkable for the light- \nness of the produce, in proportion to its bulk. It ])r()duces foliage early in tlie \nspring- in considerable abundance ; but its nutritive powers appear compara- \ntively little. \n\nXXVII. Festnca pratensis. Engl. Bot. 1592. C.Long. \nMeadow fescue grass. Nat. of Britain. \n\nAt the time of flowering, the produce from a bog soil, with coal ashes for \ntaanure, is \n\nor lbs. per acre \n\n\n\n\ndr. \xe2\x96\xa0) \n\ndr-S \n\n\n\noz. \n217800 \n\n\n\n\n\n\n\n103455 8 \n\n\n\n.13612 \n6465 15 \n\n\n\n15314 1 \n\n\n\n304920 \n121968 \n\n\n\n7146 \n= 957 \n\n=19057 \n-= 7623 \n\n\n\n7146 9 \n\n\n\n11434 8 \n446 10 \n\n\n\nGrass, 20 oz. The produce per acre \n\n80 dr. of grass weigh when dry - 38 dr \n\nThe produce of the space, ditto - 152 \n\nThe weight lost by the produce of one acre in \n\ndrying - - - \' - \n\n64 dr. of grass afford of nutritive matter 4.2 dr. \') \nThe produce of the space, ditto 22.2 dr. > \n\nAt the time the seed is ripe the produce is \n\nGrass, 28 oz The produce per acre \n80 dr. of gi-ass weigh when dry 32 dr. \') \n\nThe produce of the space, ditto 179.0* 5 \n\nThe weight lost by the produce of one acre in \n\ndrying ........ \n\n64 dr. of grass afford of nutritive matter 1.2 dr. ~) \nThe produce of the space, ditto 10.2 dr. 5 \n\nThe weight of nutritive matter which is lost by leaving the crop \n\ntill the seed be ripe, exceeding one-half of its value - 510 7 8 \n\nThe value of the grass at the time the seed is ripe, is to that of the grass at \nthe time of flowering, as 6 to 18. . \n\nThe loss which is sustained by leaving the crop of this grass till the seed be \nripe, is very great. That it loses more of its weight in drying at this stage of \ngrowth, than at the time of flowering, perfectly agrees with the deficiency of \nnutritive matter in the seed crop, in proportion to that in the flowering crop : \nthe straws being succulent in the former, they constitute the greatest part of \nthe weight ; but in the latter they are compat atively withered and dry, conse- \nquently the leaves constitute the greatest part of the weight. It may be ob- \nserved here, that there is a great difference between straws or leaves that \nhave been dried after they were cut m a succulent state, and those which arc \ndried (if I may so express it) by nature whde growing. The former retain all \ntheir nutritive powers ; but the latter, if completely dry, very little, if any. \n\nXXVIII. Lolium perenne. Engl. Bot. 315. Flo. Dan. 747. \nPerennial rye-grass. Nat. of Britain. \n\nAt the time of flowering, the produce from a rich brown loam is \n\noz. or lbs. per acre \n\nGrass, 11 o:. 8 (/n The produce per acre - 125235 = 7827 3 \n\n\n\n80 dr. of grass weigh when dry \nThe produce of the space, ditto \n\n\n\n78 \n\n\n\n34 dr. \xe2\x96\xa0 \n\n4 \n\n\n\n53156 13 = 3322 4 li \n\n\n\nThe weight lost by the produce of one acre in \n\ndrying -.-.... \n\n64 dr. of grass aflTord of nutritive matter 2.2 \'/\'\xe2\x80\xa2\xe2\x80\xa2 V \nThe pro<iuce of the space, ditto - 7.0| $ \n\nAt the time the seed is ripe, the produce is \n\ndrass, 22 oz. The produce per acre \n\n\n\n4891 15 \n\n\n\n4494 14 3 \n305 11 15 \n\n\n\n239580 =14973 12 \n\n\n\n272 \n\n\n\nAPPSNDIX. \n\n\n\nI 5 \n\n\n\nor. or llis. pel" acre \n\n71874 = +492 2 \n\n\n\n10294 \n\n\n\n10481 \n7 = 643 \n\n\n\n8 8 \n\n\n\n80 dr. of grass weigh when thy - 24 \n\nThe proch\'ce of the space, ditto 105.2| \n\nI\'ht weight lost by the produce of one acre in \n\ndrying - - \n\n64 til- of grass afford of nutritive matter 2.3 "\'\'\xe2\x80\xa2 ; \nThe produce of the space, ditto - 15.0-iV; \n\nThe weight of nutritive matter which is lost by taking the crop \nat the time of flowering, nearly one-half of its value - - S3T \nThe proportional value whicii the grass, at the time of flowciing, bears to \n\nthat at ilie time the seed is ripe, is as 10 to 11. \n\nThe [)roduce of latter-math is \n\nGrass, 5 nz. The produce per acre - - 54450 =-= 3403 2 \' \n\n64 </f. of gi-ass afford of nutritive matter 1 </>\xe2\x80\xa2. 850 12.== 53 2 12 \n\nThe proportional value wiiich the grass of the lalter-matli bears to that at \nthe time of flowering, is as 4 to 10, and to that at the time the seed is ripe, as \n4 to 11. \n\n\n\nXXIX. Poa maritima. Engl. Rot. 1140. \n\nSea meadow grass. Nat. of Britain. \n\nAt tlie time of flowering, the produce fi-om a light brown loam, is \n\n\n\n\xe2\x80\xa2Grass, 18 or. The produce per acre \n80 dv. of grass weigh when dry \nThe produce of the space, ditto \nThe weight lost by the produce of one acre in \ndrying \n\n\n\n32 dr. \n115.5J \n\n\n\n196020 \n78408 \n\n\n\nor lbs. per aci-e \n\n\n\n=12251 \n= 4900 \n\n\n\n13782 \n\n\n\n7350 \n861 \n\n\n\n64 dv. of grass afford of nutritive matter 4.2 dr. 1 \nThe produce of the space, ditto - 20.1 </r. 5 \n\nThe produce of latter-math is \n\nGrass, 18 or. The pi-oduce per acre - - 196020 0=12251 4 \n64 \xc2\xab/r. of grass afford of nutritive matter \\ dr. SU62 13 = 191 6 31 \n\nThe proportional value which the grass of the latter-math bears to that at \nthe time of flowering, is as 4 to 18. \n\n\n\nXXX. Cyitomi-us cristatns. Engl. Bot. 316. Host. G. A. 2, t. 96. \nCi-ested dog\'s-tail grass. \n\nAt the time of flowering, the produce from the brown loiun, with ma- \n\nYMVC, is \n\n\n\nGrass, 9 or. The produce per acre \n\n80 dr. of grass weigh when dry - 24 dr. \\ \n\nThe produce of the space, ditto - 43 dr. [ \n\nThe weight lost by tlie produce of one acre in \ndrying \n\n\n\noz. or lbs. per acre \n\n0= 6125 10 \n\n29403 = 1837 11 \n\n\n\n64 dr. of grass afford of nutritive matter 4.1 dr.\\ \nThe produce of the space, ditto ^"tV J \n\nAt the time the seed is ripe the produce is \n\nGrass, 18 oz. The produce per acre \nSO dr. of grass weigh when dry - 32 dr. ") \n\n\'l"he produce of tlie space, ditto 115.0-*, 3 \n\nI\'lie weight lost by the proilucc of one acre ir\\ \ndrying - - - \n\n\n\n4287 15 a \n6508 7 == 406 13 7 \n\n\n\n196020 =12251 \n78408 = 4900 \n\n\n\n4 \n\n\n\n\n7350 12 \n\n\n\n6806 \n\n\n4 \n\n\n\n\n\n1871 \n\n\n11 \n\n\n8 \n\n\n4934 \n\n\n8 \n\n\n8 \n\n\n239 \n\n\n4 \n\n\n8 \n\n\n9528 \n\n\n12 \n\n\n\n\n\n2858 \n\n\n10 \n\n\n\n\n\n6670 \n\n\n2 \n\n\n\n\n\n148 \n\n\n14 \n\n\no \n\n\n\nAPPENDIX. 273 \n\nez. or lbs. per acre \n\n64 dr. of f^ass afford of nutritive matter 2.2 <fr. 7 ^g^- q^ ^^g g q \nThe produce of the space, ditto. 11.1 r/r. 5 ^ \n\nThe weight of nutritive matter wliich is lost by \ntakintf the crop at the tune of flowering, ex- \nceeding one-sixth of its v;due 71 12 9 \n\nXXXI. Jivena pratends. Engl. Kot. 1204. Fl. Dan. 1083. \nMeadow oat-grass. Nat. of Britaui. \n\nAt the time of flowering, the produce from a rich sandy loam, is \n\nGra^s, 10 ox. The produce per acre - - 108900 = \n\n80 dr. of grass weigh when dry 22 dr. > 9004.7 o \n\nThf produce of tiie space, ditto 44 dr. > ^-^y*\' ^ \xe2\x80\x94 \n\nTlie wt-igiit lost by the produce of one acre in Irving \n\n64 </r. of grass afford of nutrive matter 2.1 dr. ) "Ri^q \xc2\xab \n\nThe produce of the space, ditto 5.2^ 5 "^^^^ " " \n\nAt the time the seed is ripe the produce is, \nGrass 14 oz. The produce per acre 152460 = \n\n80 dr. of g-rass ueigh when dry 2\'^ dr. 7 a\'-\'^ih n \n\nThe produce of tiie space, ditto 67.0| 5 ^\xc2\xbb u = \n\nTlie weight lost by the produce of one acre in drying \n\n64 dr. of grass afford of nutritive matter 1 dr. \') o^qo " \n\nThe- produce of tiie space, ditto .\'3.2 dr 3 \xe2\x96\xa0\'JO\'* ^ \xe2\x80\x94 \n\nThe weight of nutritive matter which is lost by \nleavmg the crop till the seed be ripe, exceed- \ning one third part of iis value - - 90 6 \n\nThe proportional value which the crops, at the time the seed is ripe, bear \nto that at the time of flowering, is as 4 to 9. \n\nXXXII. Bromug multiftorus. Engl. Bot. 1884. Host. G. A. 1, t. 11. \n\nMany flowering brome-grass. Nat. of Britain. \n\nAt the time of flowering, the produce fi*om a clayey loam Is \n\nGrass, 33 oz. the produce per acre 359370 = 22460 10 \n\nSO </r. of grass weigli when dry - A4 dr. ) ,r,-,/--o p 10-. -<j \xc2\xab o \n\n\'I\'he produce of the space, ditto 29u.0| $ -^\'"\'\'^ i> -^ i.ioo^ b \xc2\xab \n\nThe weigiit lost by the produce of one acre in drying 10107 4 8 \n\n64</r. of grass afford of nutritive matter 5 dr. \\ oony- .0 i-r-A -n \xe2\x96\xa0,<:t \n\nThe produce of \'the space, ditto 41.1 5 ^"^\'^\xe2\x96\xa0^ ^^ ~ 1/^4 11 12 \n\nThis species is annual, and no valuable properties have as yet been disco- \nvered in the seed. It is only noticed on account of its bemg frequently found \nin poor grass lands, and sometimes in meadows. It appears from tlie above \nparticulars to possess nutritive powers equal to some of the best perennial \nkinds, if taken when in flower ; but if left till the seed tie ripe (which, from \nits early growth, is frequently the case,) the crop is comparatively of no value \nthe leaves and straws being then completely dry. \n\nXXXm. Festuca loliacea. Curt. Lond. Engl. Bot. 1821. \nSpiked fescue grass. Nat. of Uritain. \n\nAt the time of flowering, the produce from a brown rich loam, is \n\nGrass, -24 02. the produce per acre - - 261360 0=16335 \n\n80 Jr. of grass weigh when dry 35 </r. "J i^^nAs n t,^/: \n\nThe produce of the space, ditto 168 dr. $ ^**^*^ = 7146 \n\nThe weight lost by the ])roduce of one acre in drj-ing 9188 \n\n64 Jr. of grass afford of nil tritive matter 3 dr. "> ir,n\xc2\xab, j \n\nThe produce of the space, ditto 18 Jr. j ^^^^ * "= 7&5 11 \n\nM m \n\n\n\n\n\n\n\n\n\n9 \n\n\n\n\n\n7 \n\n\n\n\n\n\n274 APPENDIX. \n\nAt tlie time the seed is ripe, the produce is \n\nor. or lbs. per aci-e \n\nGrass, 16 oz. the produce per acre 174240 = lOS\'K) \n\n80 ^/r, of grass weis,\'h when dry 33 dr. > 71874.0 4492 2 \n\nThe produce of tlic space, ditto lOSy 5 \n\nThe weight lost by the produce of one acre in drying- 6397 14 \n\n()4 (//-. of grass afiord of nutritive matter 3.1 dr. \\ hrah o =\xc2\xbb 55" 2 \nTlie prochice of the space, ditto 13 dr. 5 \n\nThe latter-math produce is \nGrass, 5 oz. The produce per acre - - 54450 = 3403 2 \n\n64 dr. of grxss afford of nutritive matter 1.1 dr. 1063 7 = 66 7 7 \n\nThe weigiit of oytritivc matter which is lust by \nleaving tlie cro|) till the seed be ripe, exceed- \ning one fourth part of its value -..--. 212 11 \n\nThe proportional value which the grass, at the time of flowering, bears to \nthat at the time the seed i-i ripe, is as 12 to 13 ; and the value of the latter- \nmath stands ih proportion to tliat of the crop at the time of flowering, as 5 to \n12, and to that of the crop taken at the time the seed is ripe, as 5 to 13. \n\nThis species of fescue greatly resembles the rye grass, in habit and \nplace of growth : it has excellencies which make it greatly superior to that \ngrass, for the pur[)oses of either hay or permanent pasture. This species \nseems to improve in produce in proportion to its age, which is directly the re- \nverse of the Lolium pereime. \n\nXXXIV. Poa cristata. Host. G. A. 2, t. 75.\xe2\x80\x94 Aira Cristata. Engl. Bot. 648. \nCrested meadow grass. Nat. of Britain. \n\nAt the time of flowering, the produce from a sandy loam is \n\nox. or lbs. per acre \n\nGrass, 16 or. The produce per acre - - 174240 = 10890 \n80 ^r. of grass weigh when dry 36 rfr ^ ^g^g q = 4900 Si \n\nIhe produce oi the space, ditto H^TB" j \n\nThe weight lost by the produce of one acre in drying - - 5989 8 \n\n64 r/r. of grass afford of nutritive matter 2 dr. \'i e/tAe n lAri K Q \n\nThe produce of the space, ditto 8 dr. 5 ^\'**^ U \xe2\x80\x94 JW ^ u \n\nThe prochice of this species, and the nutritive matter that it affords, are \nequal to those of the Festuca ovina at the time the seed is ripe : they equally \ndelight in dry soils. The greater bulk of grass in proportion to tlie weight, \nwith the comparative coarseness of the foliage, render the Poa cristata infe- \nrior to the Festuca ovina. \n\nXXXV. Festuca mijiirus. Engl. Bot, 1412. Host. G. A. 2, t. 93. \nWall fescue grass. Nat. of Britain. \n\nAt the time of flowering, the produce from a light sandy soil is \n\noz, or Jbs. per acre \n\nGrass, 14 oz. The ])roduce per acre - - 152460 \n80 dr. of grass weigh when dry 24 dr. "i ^c-oo n. \n\nThe produce of the space, ditto 67||y 5 ^^\'"^^ " \n\nThe wt ight lost by the produce of one acre in drying - \n64 rfr. of grass afford of nutritive matter 1.2 </r. } "^/q a, \nThe produce of the space, ditto 5.1 </r. $ "^ \n\nThis species is strictly annual ; it is likewise subject to the nist; and the \nabove being its whole produce for one year, it ranks as a very inferior grass. \n\nXXXVI. Mra flexuosa. Engl. Bot. 1519. Host. G. A. 2, t. 43. \nWaved mountain hair-grass. Nat. of Britain. \n\nAt the time of flowering, the produce from a heath soil is \n\noz. or lb\xc2\xbb. per acre \n\nGrass, 12 oz. The produce per acre - - 130680 8167 8 (J \n\n\n\n9528 \n\n\n12 \n\n\n\n\n\n2858 \n\n\n10 \n\n\n\n\n\n6670 \n\n\n2 \n\n\n\n\n\n223 \n\n\n5 \n\n\n4 \n\n\n\nAPPENDIX. 275 \n\noz. or lbs. per acre \n\n80rfr,of ^asswe5ghwhendry - 31 ^/r.^ ? 5^638 0=3164 14 8 \nThe produce of the space, ditto - 74y S \n\nThe weigiit lost by the produce of one acre in drying - - 5002 9 8 \n64 f/r. of prass afford of nutritive matter \\.2 dr. > 3062 13 191 6 13 \n\nThe produce of the space, ditto 4.2 dr. ) \n\nXXXV^II. ffordeitm hulbomm. Hort. Kew. 1, P. 179. \n\nBulbous barley grass. Nat. of Italy and the Levant. Introduced 1770, by \n\nMons. Richard. \n\nI \n\nAt the time of flowering, the produce from a clayey loam with manure, is \n\n\' OS, or lbs. per acre \n\nGrass, 35 oz. The produce per acre - - 381150 =23821 \n\n80 ./r. of grass weigh when dry - 93 ./r. 7 ^^.^^224 q = 9826 8 6 \nThe produce or tlie space, ditto - 2:>l dr.- 3 \n\nThe weight lost by tlie produce of one acre in drying - - 13994 7 10 \n\n64 </r of grass afford of nutritive matter 3.2 ^A". } 20844 2 1302 12 2 \nThe produce of the space, ditto - 30.2 1 5 \n\nXXXVIII. Festuca calamaria. Engl. Bot. 1005. \nReed-like fescue grass. Nat. of Britain. \n\nAt the time of flowering, the produce from a clayey loam is \n\nGrass 80 oz. The produce per acre \n80 dr. of grass weiglit when dry 28 dr. 7 \n\nThe produce of the space ditto - 448 dr. 3 \nThe weightlostby the produce of one acre in drying \n64 dr. of grass afford of nutritive matter 4.2 dr. > \nThe produce of the space, ditto - 90 dr. 5 \n\nAt the time the seed is ripe the produce is \nGrass, 75 oz. The produce per acre ... \n80 dr. of grass weigh when dry 19 dr. \'} \n\nThe produce of the space, ditto 283 dr. 3 \n\nThe weight lost by the produce of one acre in drying - \n64 dr. of grass afford of nutritive matter 3 dr. ^ \nThe produce of the space, ditto 56,1 dr. 5 \n\nThe weight of nutritive matter which is lost by \n\nleaving the crop till tiic seed be ripe, being \n\nnearly one third part of its value 1435 11 2 \n\nThe proportional value which the grass of the time the seed is ripe, bears \nto that, at the time of flowering, is as 12 to 18. \n\nThis grass, as has alrea<ly been remarked, produces a fine early foliage in the \nspring. The produce is very great, and \\U nutritive powers are considerable. \nIt appears, from the above particulars, to be best adapted for hay. A very sin. \ngular disease attacks, and so\'Tietimes nearly destroys the seed of this grass : \nthe cause of this disease seems to be unknown ; it is denominated Clavus, by \nsome ; it appears by the seed swelling to three times its usual size in length \nand thickness, and the want of the carcle. Dr. VVilldenow describes f wo dis- \ntinct species of it : 1st, the simple clavus, which is mealy and of a dark colour, \nwithout any smell or taste ; 2d, the malignant clavus, which is violet blue, or \nblackish, and internally too has a bluish colour, a ftetid smell, and a sharp pun- \ngent taste. Bread made from grain affected with this last species, is of a bluish \ncolour ; when eaten, produces cramps and giddiness. \n\nXXXIX, Bromus liltormts. Host. G. A. P. 7, t. 8, \n\nSea-side brome grass. Nat. of Germany, grows on the banks of the Da- \nnube and other rivers. \n\nAt the time of flovvenng, the produce from a clayey loam is \n\noz. or Ibx. per acre \n\nGrass, 61 oz. The produce per acre - - - 6642&0 =41518 2 \n\n\n\noz. \n871200 \n\n\n\n\n\nor lbs. per acre \n= 54450 \n\n\n304920 \n\n\n\n\n\n= 19057 8 \n\n\n\n\n\n. \n\n\n. \n\n\n35392 8 \n\n\n\n\n\n61256 \n\n\n4 \n\n\n= 3828 8 \n\n\n4 \n\n\n816750 \n\n\n\n\n\n=51046 14 \n\n\n\n\n\n193978 \n\n\n2 \n\n\n=12123 10 \n\n\n\n\n\ns - \n\n\n. \n\n\n38923 4 \n\n\n\n\n\n38285 2 \n\n\n=2392 13 \n\n\n2 \n\n\n\n276 \n\n\n\nAPPENDIX. \n\n\n\noz. or Ibsi per acne \n\n80 r/r. of grass weiffh when dry - 41 rfr. / o^o.^o ,/^ r.. wr> \xc2\xab .\xc2\xab \nTi.e p.oauce of the si)ace, ditto - 50U\xc2\xab^ \\ "^^^^^S 10 ==21:>78 10, \n\nThe weight lost by the produce ot\'one acre in drying \n64 (//\'. ot )<rass afford ot" nutritive matter l.J dv. \nThe prodnce ot the space, ditto 22.3J \n\nAt the; time the seed is ri[)e, the produce is \nGrass, 56 oz. The produce per acre \n8U dv of ffrass vveij;h when dry 32 dr. \n\nThe prochice of tl\xc2\xbbe space, (htto 358| \n\nThe weig\'iit lost by tlie pnxhice of one acre in drying \n64 (Iv. of grass afford of nutritive mailer >.<! ilr. ^ \nTile prochice of ti>e spuce, (htto 196 dr. 3 \n\nTlie weig-i\\t of nuti-ilive matter which is lost by \ntaking the cro]) at the time of flowering, \neJJceeding one half of its value - ... - 1111 5 6 \n\nThe proportional value which the grass at the time of flowering bears to \nthat at the time the seed is ripe, is as 6 to 14. \n\nTiiis species greatly resembles the preceding in habit and manner of \ngrowth ; but is inferior to it in value, which is evident from the deficiency of \nits produce, and ol tiu\' nutritive matter afforded liy it. The whole plant .is \nlikewise coarser and of greater bulk m j)roporlion to its weight. The seed \nis alfecied with the same disease which destroys that of the former spe- \ncies. \n\n\n\n- \n\n\n- \n\n\n20540 \n\n\n1 \n\n\n6 \n\n\n15567 \n\n\n4 \n\n\n= 973 \n\n\n1 \n\n\n4 \n\n\n6U9840 \n\n\n\n\n\n=38115 \n\n\n\n\n\n\n\n\n243936 \n\n\n\n\n\n=15246 \n\n\n\n\n\n\n\n\n\n\n- \n\n\n22869 \n\n\n\n\n\n\n\n\n33350 \n\n\n\n\n\n= 2084 \n\n\n6 \n\n\n10 \n\n\n\nXL. Festnca eliator. Engl. Rot. 1593. Host. G. A. 2, t. 79. \n\nTall fescue grass. Nat. of liriiain. \n\nAt the time of flowering, the produce from ablack rich loam, is \n\noz, or lbs. per acre \n\n\n\nGrass, 7S oz. The produce per acre \n80 </;\xe2\x80\xa2. of grass weigh when dry - 28 dr. \') \n\n. \'i\'he proiUicc of the space, ditto \xe2\x80\xa2 420 dr. $ \nThe weight which is lost by the produce of one ) \nacre in drying .--..- 3 \n64 (/;\xe2\x80\xa2. of grass afford of nutritive matter 5 dr. } \nTlie produce of the space, ditto - 93.3 dr.y \n\n\n\n816750 \n285862 \n\n\n\n=51046 14 \n\n8 -17866 6 8 \n\n33180 7 8 \n\n63808 9 \xe2\x80\x94 3988 9 \n\n\n\n816750 \n285862 \n\n\n\n=.51046 4 \n8 =17866 6 \n\n\n\n3 dr. I \n\n\n\n38285 2 \n\n\n\n33180 7 \n\' 2392 13 \n\n\n\nAt the time the seed is ripe the produce is \nGrass, 75 or. The produce per acre \n80 <fr. of grass weigh when dry - 28 dr. \n\nThe produce of the space, ditto 420 dr \n\nThe weight lost by the produce of one acre in \n\ndryii g . - . - \xe2\x80\xa2 \n\n64 dr. of gTass aflbrd of nutritive matter 3 \nThe produce ot\' the space, ditto - ^^ , \n\nThe weight of nutritive matter which is lost by\'leaving the crop \n\ntill the seed be ripe, exceechng one-tliird part of its value 1595 3 7 \n\nThe proportional value which the grass at the time the seed is ripe, bears \nto that at the time of flowering, is as 12 to 20. \n\nThe prodvice of latter-math is \n(irass, 23oi. The produce per acre - - 250470 0=15654 6 \n64 dr. of grass aflbrd nutritive matter 4 dr. - 156,i4 6 = 978 6 6 \n\nThe proportional lalue which the grass of the latter-math bears to that of \nthe crop, is as 16 to 20 ; and to that at the time the seed is ripe, as 12 to 16, in- \nverse. \n\nThis species of fescue is closely allied to the Festnca pratensin, from which \nit diife.rs in little, except t!iat it is larger in every rtspect. The produce is \nnearly three times that of the F. fttatcii.v.s. and the nutritive powers of the \ngrass arc superior in direct proportion, as 6 to 8. \n\n\n\nAPPENDIX. 277 \n\nXLI. J^rnrdva stricta. Eng. not. 290. Host. G. A. 2, t. 4. \nUprifj^ht mat-grass. Nut. of IJritain. \n\nAt the time the seed is ripe the produce is \n\noz. or lbs. per acre \n\nGrass, 9 oz. The prorhice per acre - - 98010 = 6125 10 \n\n80 dr. of cfrass wei^h when dry - 32 t\'"- > .->mA^ \xc2\xab \xc2\xab ^ \n\nTh.^ produce of th<- space, ditto - 57 2} ^ = 24o0 4 \n\nThe v/cifi^ht lost by the produce of one acre i\'l drying 3675 6 \n\n64 f/r. of grass afford of nu\'ritive matter 2.1 \'^r.^ oa^c in \xe2\x80\xa2.\xe2\x80\xa2^ ^r -r. \n\nThe produce of the space, ditto - 5.0J j 3445 10-= 215 5 10 \n\nXLII. Triticnm, Sp. \nWheat grass. \n\nAt the time of flowering, the produce from a rich sandy loam is \n\noz. or lbs. per acre \n\nGrass, 18 oz. The produce per acre - . - 196020 =12251 4 \nSO (h\'. of grass w^igh when drv - 33 \'/\'"O \n\nthe produce of the space, ditto - 115^ S ~^\'*^^ = 4900 8 \n\nTlie weight lost by the produce of one acre in drying - 7350 12 \n\n64 </r. of grass afforil of nutritive matter 2.2 /\xe2\x80\xa2/\xc2\xbb\xe2\x80\xa2. ) 7fi\xc2\xab7 n /17k q a \n\nThe produce of the space, ditto - 11.1 Jr. 5 \' \' u =- *^e y O \n\nXLIU. Festncafuitans. Curt. Lond. Engl. Bot. 1520. Poa fluitans. \nFloating fescue grass. Nat. of Britain. \n\nAt the time of flowering, tlie produce from a strong tenacious clay, is \n\noz. or lbn. per acre \n\nCrass, 20 or. The produce per acre - - 217800 0=^13612 8 \n80 r/r. of grass weigli when dry - -24 Jr./ g^ 4fis<> to n \n\nThe produce of the space, ditto - - 96 Jr. $ \xc2\xb0\'^\'^^" = 4083 12 \nThe weiglit lost by the pt\'oduce of one acre in drying - - 9528 12 \n64 J;-, of grass afford of nutritive matter l.o Jr. ? ^^q^ ^ \xe2\x80\x9e \xe2\x80\x9e \n\nThe produce of the space, ditto - 8.3 Jr. S ^^ = o72 o 7 \n\nThe above produce was taken from grass tliat liad occupied the ground for \nfour years, during wliich time it had increase<l every year; it tlierefore ap- \npears contrary to what some have supposed to be capable of being cultivated \nin perennial pastures. \n\nWAV. nolcmbtnatnu. Curt. Lond. El. Dan. 1181. \n\nMeadow soft grass. Yorkshire grass. Nat. of Britain. \n\nAt the time of flowering, the produce from a strong clayey loam is \n\noz. or Ihn. per acre \n\nGrass, 28 oz. The produce per acre - . 304920 0=19057 8 \n80 Jr. of grass weigh wiuMi dry - 26 rfr. ") m^toc ia cr^r, \xc2\xab ... \n\nThe produce of the space, ditto - 157.2? $ 106585 14=6661 9 14 \nThe weight lost by t!ie produce of one acre in drying - - lj395 14 2 \nfi-l Jr. of grass afford of nutritrve matter 4 Jr. ) ,\xe2\x80\x9e.,,_ q ,,\xe2\x80\x9e, , \xe2\x80\x9e \n\'i\'he produce of the space, ditto - 28 Jr. 3 ^^^^\' 0=1191 1 8 \n\nAt the time the seed is ripe, the produce is \n\nGrass, 28 or. The produce per acre \xe2\x80\xa2 - 304920 ==19057 8 \n80 Jr. of grass vveigli when dry - 16 </r. ^ \n\nIhe produce of the space, ditto - 89.;^ 5 0^984 0=3811 8 \n\nThe weight lost by the produce of one aorc m drying - - 15246 \n\n64 dr. of grass afford of nutritive matter 2. > dr. ? ijino => 818 14 \xe2\x80\xa2 \nThe produce of the space, ditto - 19.1 Jr. 5 \n\n\n\n278 APPENDIX. \n\nUc. per acre \nThe weight of nutritive matter which is lost by leaving the crop \n\ntill the seed be ripe, exceeding one-third part of its value - 372 3 8 \nThe proportional value which the grass at the time the seed is ripe, bears \nto that at tlie time of flowering, is as 11 to 12. \n\nXLV. Festuca ditmelorum. Flo. Dan. 700. \n\nPubescent fescue grass. Nat. of Britain. \n\nAt the time of flowering, the produce from a black sandy loam, is \n\noz. or lbs. per acre \n\nGrass, 16 oz. The pr :duce per acre - - 174240 =10890 \n\n80 rfr. of grass weigh when dry . - - 40 dr."} q-,oA n -a Mr n n \n\nThe produce of the space, ditto - 120 Jr. 5 ^^^^0 = o44.5 9 \nThe weight lost by the produce of one acre in \n\ndrying - -\' 5445 \n\n64 </r. of grass aflTord of nutritive matter Ir/r. "> __\xe2\x80\x9e \xe2\x80\x9e im o c \n\nThe produce of the Si >ace, ditto - - 4 Jr. 5 ^\'^^ " "^ UU ^ a \n\nXLVI. Poafirtilis Host. G. A. \n\nFertilis meadow grass. Nat. of Germany. \n\nAt the time of flowering the produce from a clayey loam, is \' \n\noz. or lbs. per acre \n\nGrass, 22 oz. The produce per acre - - 239580 =14973 12 \n80 ./,-. of grass weigh when dry - \' ff\'l U5779 ^ = 78&1 3 8 \nThe produce 01 the space, ditto - lo4y 3 \n\nThe weiglit lost by the produce of one acre in \n\ndrying --..-..--- 7111 8 8 \n\n64rfnof grass afford of nutritive matter 4 2 Jr. ^ jjg845 7 _ io52 13 7 \nThe produce of the space ditto - 24.3 dr. 5 \n\nIf the nutritive powers and produce of this species, be compared with any \nother of the same family, or sucli as resemble it in habit and the soil which it \naffects, a superiority will be found, which ranks this as one of the most valuable \ngrasses ; next to the Poa angitstifolia, it produces the greatest abundance of \nearly foliage, of the best quality, which fully compensates for the comparative \nlateness of flowering. \n\nXLVII. Jlrundo colorata. Hort. Kew. I.P. 174. Engl. Bot, 402. Phalaris \nai\'iuidinacea. \nStriped-leaved reed grass, Nat. of Britain. \n\nAt the time of flowering, the produce from a black sandy loam is \n\noz. or lbs. per acre \n\nGrass, 40 or. The produce per acre - - 435600 0=27225 \n\n80 f/r. of grass weigh when dry 56 dr.\'> mcnon n i99ci A. n \n\nThe produce ofthe space, ditto - 28.8 Jr. 5 ^^^^^^ 0=12251 4 \n\n64 Jr. of grass afford of nutritive matter . 4 Jr 7 otooc n I7ni Q n \n\nThe produce of the space, ditto - 40 Jr. 5 \'^\'^^^ u = i/\'ui y u \n\nThe strong nutritive powers which this grass possesses recommend it to \nthe notice of occupiers of strong clayey lands, which cannot be drained. Its \nproduce is great, and tlie foliage will not be denominated coarse, if compared \nwith those which afford a produce equal in quantity. \n\nXLVm. Trifolmm prntmse. W. Bot. 3, P. l."7. \n\nBroad-leaved cultivai ed clover. Nat of Britain. \n\nAt the time the seed is ripe flower, the produce from a rich clayey \nloam is \n\noz. or lbs. per acre \n\nGrass, 72 oz. The produce per acre - - 784080 =49005 \n\n\n\nAPPENDIX. \n\n\n\n279 \n\n\n\n80 dr. of grass weigh when dry - 20 dr. 7 \n\nThe produce of the space, ditto - 288 dr. $ \n\nThe weight lost by the produce of one acre in \n\ndrying - - \n\n64 dr. of grass afford of nutritive matter 2.2 dr. \nThe produce of the space, ditto - 45 dr, \n\n\n\n9z. \xc2\xabF lbs. per acre \n\n196020 =12251 \n\n\n\n30628 2 \n\n\n\n3675 \n1914 \n\n\n\nIf the weight which is lost by the produce of this species of clover, in \ndrying, be compared with that of many of the natural grasses, its inferior va- \nlue for the purpose of hay, compared to its value for green food, or pasture, \nwill appear ; for it is certain that the difficulty of making good hay increases \nin proportion with the quantity of superfluous moisture which the grass may \ncontain. Its value for green food, or pasture, may further be seen by com- \nparing its nutritive powers, with those manifested by other plants generally \nesteemed best for this purpose. \n\nTrifolium pratense (as above) affords of nutritive matter - 2.2 dr. \n\n\n\nXLIX. Trifolinm ripens (white clover) from an equal quantity of \ngrass \xe2\x80\xa2.. \n\n\n\n2.0*. \n\n\n\nL. Ditto, variety, with brown leaves, ditto . - - - . 2.2 dr. \nTile grass of the T*. pratense, therefore, exceeds in value that of the T. \nrepens, by a proportion as 8 to 10 ; but it is of equal proportional value with \nthe brown variety. \n\nLI. Burnit (Poterium sanguisorba) affords of nutritive matter - 2.2 dr. \nLII. Bunias orientalis (a newly introduced plant,) ditto - - - 2.2 dr. \n\nThe proportional value of these two last, and of the T. pratense, and the \nbrown-leaved variety of T. repens, are equal ; they exceed the T. repens as 8 \nto 10. \n\nThe comparative produce of these four last-mentioned species, per acre, \nhas not been ascertained. \n\nLIU. Trifolium macrorhizum. \n\nLong-rooted clover. Nat. of Hungary, \n\nAt the time the seed^is ripe, the produce from a rich clayey loam is \n\n\n\nGrass, 144 oz. The produce per acre \n80 dr. of grass weigh when dry - 34 <fr. \n\nThe produce of the space, ditto - 979y \nThe weight lost by ihe produce of one acre in \n\ndrying \n\n64 dr. of grass afford df nutritive matter 2 3 dr. } \nThe produce of the space, ditto - -99 dr. 5 \n\n\n\n1568160 \n666468 \n\n\n\n67381 14 \n\n\n\nor lbs. per acre \n=98010 \n\n=41654 4 \n\n\n\n56355 12 \n= 4211 5 14 \n\n\n\nThe root of this species of clover is biennial : it penetrates to a great depth \nin the ground, and is in consequence little affected by the extremes of wet \nor dry weather. It requires good shelter, and a deep soil. The produce, \nwhen compared to that of others that are allied to it in habit, and place of \nl^owth, proves greatly superior. The following particulars, some of which \nrefer to results stated in the next two pages, will make this manifest : \n\n\n\nTrifolium pratense \nBroad leaved clover \n\nMedicago sativa. \nLucern. From ia soil of the \nlike nature -^ \n\n\n\n("Produces per acre. Grass \n\n< Ditto, Hay, - \n\n( Affords do. of nutritive matter \nC Produces per acre. Grass \n\n< Ditto, Hay, \nCAfl[\xc2\xbbrds mi nutri^ye matter - \n\n\n\nlbs. 49005 \n12251 \n\n1914 \n707^5 \n28314 \n\n1659 \n\n\n\n280 APPENDIX. \n\nHedysarum ombvycha C Produces per acre. Grass - \xe2\x80\xa2 - \xc2\xbb.. 8R48 \nCAliords oi nutritive matter - - bl4 \n\n\n\nThe weight of nutritive matter affonled by the produce of the T. \nmacrovhizum, excsreding that of the T. pruteme, in proportion, \n\nnearly as T to 15 2297 \n\nThe uroponionul vahie of the grass of T. pratense to that of T. \nmacrorhiziim, is lU to 11. \n\nThe wcijjht of niitiitlve matter aflTorded by the T. macrorhzuin, ex- \nceeding that of the jyiedicago sutiva, in proportion nearly as l3 \n\ntooj - -. - - 2552 \n\nThe proportional value of the grass is as 11 to 6. \nThe vveigiit of nutritive matter which is aiibrdcd by the produce of \ntlie 7\'. tiiacror/iizimh, exceeding thp.t of the Hedysarum onobrydiis in \n\nproportion nearly a\xc2\xa35tofi7 - 3897 \n\nThe proportional value of the grass, like that of the 2\\ pratense, \nis as 11 to 10. \n\nThe produce of each of the above-mentioned species was taken from a \nsimilar soil, and in the same situation, the conchisions must thereture be con- \nsidered positive, with respect to such soils only. It is evident that more than \ntwice the quantity of nutritive matter is afibrded by the produce of one acr\xc2\xab \nof the T. macruvldzuiii, than from the produce ot an equal space covered by \nthe T. prutense. Us short diuation in the soil (for it sown early in the au- \ntumn, on a rich light soil, it is oidy an annual plant) renders it lit only for \ngreen food or hay ; this in some measure lessens its value, when compared \nwith the T. pratense. It possesses tlie essenUal property of aflordini^ abun- \ndance of good seed ; and if the ground be kept clear of weeds, it sows itself, \nvegetates, and grows rapidly, without coveringin, or any operation whatever. \nFor four years it has propagated itself in tl\'is manner, on the space of ground \nwhich it now occupies, and from wliich tli;s statement of its comparative va- \nlue is made. The produce of lucern in grass, comes nearer to this species in \nquantity, but is gTeath deficient in nutritive matter, as much as 13 to 33. \nThe long conthiuance of hicern in the soil is therefore the onU merit which \nit possesses above the two last-itientioned species ; and when that is the object of \nthe cultivator, it will of necessity have the preference. \n\nThe value of the grass of saintfoin is ecjual to tliat of the T. pratense ; and \nprojiortionally less than that of the TrifAu/m macrorfdzimi, as 10 to .11. The \nquantity of gTass is very small, and on soils of the nature above described, it \nis doubtless inferior. However, from the superior vaiue oi ciie gra^.s, on dry \nhilly situations or chalky soils it inaj\' in such situations possibly be their supe- \nrior in every respect. \n\nLIV. Medic/igo Saliva. Wither. B. 3, P. 643. \nLucern. Nat. of Britain. \n\nAt the time the seed is ripe, the produce frcm a rich ckiyer loam is \n\noz or lbs. per acre \n\nGrass, 104 oz The produce per acre - - 1132560 =-70785 \n\n80 c/,^r,fgrass weigh when dry - "i^? ,<"\xe2\x80\xa2\xe2\x80\xa2? 453024 0-28314 \nThe produce of the space, ditto - 66D.Cf 5 \nThe weight lost by the produce of one acre in \n\ndicing . . - 42471 \n\n64 f/r. of gr.t.ss afibrd of nutritive matter 1.2 dr. 1 nc:-AA c -jt^-n a c \n\nThe produce of the space, ditto - 39 ./,-. $ ^^^"^ 6 = 7bo9 6 \n\nLV. Hedysanmi onobrychis. Wither. 3. P. 628. \nSaintfoin. Nat. of Britain. \n\nAt the time the seed is ripe; the produce from a rich clayey loam is \n\noz. or lbs. per acre \n\nGrass, 13 as. The produce per acre - . 141570 == 8848 2 \n\n\n\noz. \n130680 \n\n\n\n\n\n_- \n\n\nlbs. per acre \n8167 8 \n\n\n52272 \n\n\n\n\n\n= \n\n\n3267 \n\n\n\n\n\n\n\n\n. \n\n\n\n\n. \n\n\n4900 \n\n\n8 \n\n\n\n\n\n7657 \n\n\n\n\n\n^ \n\n\n478 \n\n\n9 \n\n\n\n\n\n\nAPPENDIX. 281 \n\noz- or lbs. per acre \n\n80 f/r. of grass weigh when dry - 32 \'/\'\xe2\x80\xa2\xe2\x80\xa2 > ^gggS = 35J9 4 \n\nI\'he produce of Uie space, ditto - 83-5- 3 \n\nTlie wciarlit lost by tiie produce of one acre in \n\ndrying - - - - - 5308 14 \n\n64 dr. of grass afford of nutritive matter 2.2 dr. \') ^^^q j^ ^ 045 IQ 1 \n\nThe produce of the space, ditto - 8.04 > \n\nLVl. Ifordeiim pratense. Engl. Bot. 409. Host. G. A. 1. 1. 33. \nMeadow barley-grass. Nat. of Britain. \n\nAt the time of flowering, the produce from a brown loam, with manure, is \n\nGrass, 12 oz. The produce per acre \n80 dr. of grass weigh wlien dry - 32 dr. \xe2\x96\xa0) \n\nThe [)roduce of the space, ditto - 67.1 dr.^ \nThe weight lost by the produce of one acre in \xe2\x96\xa0 \n\ndrying - - - - - \n\n64 dr. of grass afford of nutritive matter 3.3 dr. ^ \nThe produce of the sp;.; c^ ditto - 11.1 dr. 3 \n\nLVII. Poa compressa. Engl. Bot. 365. \n\nFlat-stalked Meadow-grass. Nat. of Britain, \n\nAt the time of flowering, tlie produce from a gravelly soil, with manure, is \n\noz. or lbs. per acre \n\nGrass, 5 oz. The produce per acre - - 54450 = 3403 2 \n80 ,/r. of grass Avcigh when dry - 34(/r.J 23^^^ 4 = 1446 5 4 \n\nThe produce or tlve space, ditto - o4 dr. > \nThe weight lost by the produce of one acre in \n\ndrying - \'- 1956 12 12 \n\n64 dr. of grass afford of nutritive matter - 5 dr. > .2^0 ^^ ^ 265 13 14\' \nThe produce of the space, ditto - 6.1 5 "^ \xe2\x80\xa2\xe2\x96\xa0 1 \n\nThe specific characters of this species are mucli the same as those ot the \nroafc-rtilis, differing in the compressed figure of the straws and creeping \nroot onlv. If the produce was of magnitude, it would be one of the most \nvaluable" grasses ; for it produces foliage e^rly in the spring, and possesses \nstrong nutritive powers. \n\nLVIII. Poa aqiialica. Curt. Lond. Engl. Bot. 1315. \nHeed Meadow-grass. Nat. of Britain. \n\nAt the time of flowering, the produce from a strong tenaciou.s clay, is \n\noz. or lbs. per acre \n\nGrass, 186 oz. The produce per acre - - 20225540 .==126596 4 \n\nSO Jr. of grass weigh when dry - 48 f/i-. ^ 1215324 = 75957 12 \n\nThe produce of the space, ditto - 1785.2^^. S \nl"]je weight lost by the produce of one acre in \n\ndrying \n\n\n\n50638 8 \n\n\n\n64 dr. of grass afford of nutritive matter 2.2 dr. } 7C)122 = 4945 2 10 \n\nThe pro hice of tlie space, ditto - 116.1 dr. j \n\nLIX. ^ra aqnatica. Curt. Lond. Engl. Bot. 1557- \nWater hair grass. Nat. of Britain. \n\n\\t tlie time of flowering, the produce from water, is \n\noz. or lbs. per acre \n\n(h-ass, 16 oz. \'I-he produce per acre - - 1742400 ---= 10890 \n\nN II \n\n\n\n282 APPENDIX. \n\noz. or iis. per acre \n\n80 rfr. of grass weigh when dry - 24*0 o = "^^fiT .. o \n\nThe produce of the space, ditto - 76.3,V 5 \' \n\nThe weighi lost by the produce of one acre in \n\ndrying - - 7623 \n\n64 (//\xe2\x96\xa0. fff grass afford of nutritive matter 2.1 dr.\'i - _ ^ \xe2\x80\x9e\xe2\x80\x9e_ .,\xe2\x80\x9e ^(. \n\nTiie produce of the space, ditto - 9 dr. $ , ^ ^ \n\nLX. Brotniis cristatus. Triticum cristatum, H. G. A. 2, t. 24. \nSecale prostratum. Jacquiu. Nat. of Germany. \n\nAt the time O\'\' flowering\', the produce from a clayey loam, is \n\noz. or lbs. per acre \n\nGrass, 13 oz. The produce per acre - - 141570 = 8848 \n\n80 Jr. of grass weigh when dry - - o6dr.\\ rt:cno a ^.-on a n \n\nThe produce of the space, ditto - 83.1 dr. ^ ^^\xc2\xb0^^ = od>3U * U \nThe weight lost by the produce of one acre in \n\ndrying - - 5308 14 \n\n64 J)\', of grass afford of nutritive matter 2.2 dr.\'i re^n i "At: in n \n\nThe produce of the space, ditto - 8.0^?^ ^ ^^"^ \'\xe2\x96\xa0 = ^*^ ^" ^ \n\nLXI. Elyrmis Sibiricus. Hort. K. 1, P. 176. Cult. 1758, by William P. Millar. \nSiberian lyme grass. Nat. of Siberia. \n\nAt the time of flowering, the produce from a sandy loam, with manure, is \n\noz. or lbs. per acre \n\nGrass, 24 oz. The produce per acre \' - - 261360 = 16335 \n\n80 d,-. of grass weigh when dry - -^S^-] 91476 = 5717 4 \nThe produce ot the space, ditto - lo4.1j 3 \nThe weight lost by the produce of one acre in \n\ndrying ,- 10617 12 \n\n64 rf)\\ of grass afford of nutritive matter 2.1 dr.\'i 91 SR 7 = 511 7 \nThe produce of the space ditto - 13.2 dr. $ \n\nfcXII. Mra cxspiiosa. Host. G. A. 2. t. 42. Engl. Bet. 1557. \n\'llirty hair grass. Nat. of Britain. \n\nAt the time the seed is ripe, the produce from a strong tenacious clay is \n\noz. or lbs. per acre \n\nGrass, 15 oz. The produce per acre - - 163350 6 =10209 6 \n80 rf,-. of grass weigh when dry - -26rfr.7 53088 12=3318 12 \n1 he produce ot the space, ditto - ^\'^^\xe2\x96\xa0r ^ \n\nThe weiarht lost by the produce of one acre in \n\ndrying -...------ ooyi 5 4 \n\n64 (/)\xe2\x80\xa2. of grass afford of nutritive matter 2 dr.\\ e^\\{^^ \\y = 319 11 \nThe produce of the space, ditto - 7.2 dr. 3 \n\nLXni, Hordeum murinum. Curt. Lond. Engl. Bot. 1971. \nWall barley grass. Way Bennet. Nat. of Britain. \n\nAt the time of flowering, the produce from a clayey loam, is \n\noz. or lbs. per acre \n\nGrass, 18 oz. The produce per acre - - 196020 0=12251 4 \n80 dr. of grass weigh wlieii dry - 28 dr. } gggQj, q _ ^287 15 \n\nThe produce of the space, ditto 100.O.J. 3 \n\nThe weight lost by the produce of one acre in \n\ndrying . " - - - , 7963 5 \n\n64 Jr of grass afford of nutritive matter 3 dr.\'i 2679 15 = 167 7 15 \nThe produce of the space, ditto - ^-^^g ^ \n\n\n\nAPPENDIX. 283 \n\nLXIV. Avena flavesceiis (Jurt. Lond. Engl. Bot. 952. \nYellow oat grass. Nat. of Britain. \n\nAt the time of flowering, the produce from a clayey loam, is \n\noz. or Ibs^tv acre \n\nGrass, 12 oz. The produce per acre - - 130680 \' = 8157 8 \n80 Jr. of Krass weigh when dry - 28 J,..-> ^.^\xe2\x80\x9eg 0=2858 10 \n\n1 he produce ot the space, ditto - o/.l dr. 3 \n\nThe weight lest by the produce of one acre in \n\ndtying - 5308 14 \n\n64 c/r of grass afford of nutritive matter 3.3 </n^ \xe2\x80\xa2vp.r\'r n A78 Q n \n\nThe produce of the space, ditto ll.l dr. S \'^^\' "~ \n\nAt the time the seed is ripe the produce is \nGrass, 18 OS. The produce per acre - - 196020 0=12251 4 \n80 rfr. of grass weigh when dry - 32 *0 ^^^^ 0=4900 8 \n\nThe produce of the space, ditto - 115.0y 5 \nThe weight lost by the produce of one acre in \n\ndrying ...- - 7350 12 \n\n64 r/r of grass afford of nutritive matter 2.1 rfr.^ gg^. ^ _ ^30 ^l. 5 \n\nThe produce of the space ditto - IO.O5 5 \n\nThe weight of nutritive matter which is lost if the crop be left till \n\nthe seed be ripe, exceeding oue-tenl!i part of its value - 47 13 11 \n\nThe proportional value which the grass, at the time the seed is ripe, bears \nto that at the time of flowering is as 9 to 15. ^ \n\nThe produce of latter-math is \n\nGrass, 6 oz. The produce per acre - - 65340 = 4803 12 \n\n64 i/r. of grass afford of nutritive matter 1.1 </r. 1276 2 = 79 12 2 \n\nThe proportional value which the grass of the latter-math bears to that at \nthe time of flowering, is as 5 to 15 ; and to that at the time the seed is ripe, as \n5 to 9. \n\nThis species is pretty generally cultivated in many parts of this kingdom ; \nand it appears from the above details to be a valuable grass, though inferior to \nmany others. \n\n\n\nLXV. Bromiis sterilis. Engl. Bot. 1030. Host. G. A. 1. t. 16. \nBarren brome grass. Nat. of Britain. \n\nAt the time of flowering, the produce from a sandy soil, is \n\noz. or lbs. per acre \n\nGrass, 44 oz. The produce per acre 479160 =29947 8 \n\n80 ffr. of grass weigh when dry - 45 dr.^i \xe2\x80\x9e ,, ..\xe2\x80\x9e _ j. \n\nThe produce ofthe space, ditto 396 rfr.5 \'^\'^^527 8=16845 7 S \n\nThe weight lost by the produce of one acre in \n\ndrpng 13102 8 \n\n64. //-.of grass afford of nutritive matter Jdr.J 3^43^ 6=2339 10 \nThe produce or the space, ditto - 55 dr. y \n\n64 dr. of the flowers afford of nutritive matter 2.2 dr. The nutritive powei-s \nof the straws and leaves are, therefore, more than twice as great as those of \nthe flowers. This species, being strictly annual, is of comparatively little va- \nlue. The above particulars shew that it has very considerable nutritive pow- \ners, more than its name would imply, if taken at the time of flowering ; but if \nleft till the seed be ripe, it is, like all other annuals, comparatively of no \nvalue. \n\n\n\nLXVI. Holcua mollis. Curt. Lond. Wither. B. 2. P. 134. \nCreeping soft grass. Nat. of Britain. \xc2\xbb \n\n\n\n284 \n\n\n\nAPPENDIX. \n\n\n\nAt the time of flowering", the jModuce fVom a sandy soil, is \n\n\n\n544500 \n217800 \n\n\n\nor lbs. per acre \n\n\n\n\nin \n\n\n\n=34031 4 \n=13612 \n\n\n\n8 \n\n\n\n20418 12 \n2 = 2392 13 \n\n\n\n357590 \n135036 \n\n\n\n=21099 \n= 8439 \n\n\n\n6 \n12 \n\n\n\nGrass, 50 oz. The produce per acre \n80 (Ir of g-rass weigli whgn dry - 32 dr. \n\nThe proi^uce of the space, ditto 320 dr. \n\nThe weigl)t lost by the produce of one acre in \n\ndrying- .._..- \n\n64 dr. of grass afford of nvitritive matter 4.2 dr.] \nThe produce of the space, ditto 56.1 dr. \n\nAt the time the seed is ripe tlie produce is \n\nGrass, 31 oz. The produce per acre \n80 dr. of grass weigh when dry - 32 dr. \') \n\nThe produce of the space, ditto \' 198. 1|. 5 \nThe weight lost by the produce of one acre in \n\ndrying \n\n64 dr. of grass afford of nutritive matter 3.2 dr. \') \nThe produce of the space, ditto 27. OA 5 \n\nThe weight of nutritive matter which is lost by leaving the crop \n\nt\')] the seed be ri])e, being nearly one-half of its value - 1238 \n\n64 ih, of the roots afford of nutritive matter 5.2 dr. \n\nTlie proportional value which the grass, at the time the seed is ripe, bears to \nthat at the time of flowering, is as 14 to 18. \n\nThe above details prove this grass to have merits, which, if compared with \nthose of other species, rank it with some of the best grasses. The small loss \nof weight wJiich it sustains in drying might be expected from the nature of \nthe substance of the grass ; and the loss of weight at each period is equal. \nThe grass alfords the greatest quantity of nutritive matter when in flower, \nwhich makes it rank as one of those best adapted for hay. \n\n\n\n12659 10 \n18461 15 = 1153 13 15 \n\n\n\n15 \n\n\n\nLXVII. Poa fertilis. Var. B. Host. G. A. The species. \n\nFertile meadow g-rass. \\\'ariety 1. Nat. of Gei-many. \n\nAt the time of flowering, the produce from a brown sandy loam, is \n\n\n\n34 dr. \n1561 \n\n\n\nGrass, 23 oz. The produce per acre \n\n80 dr. of grass weigli when dry \n\nThe produce of the space, ditto \xe2\x96\xa0^\xe2\x80\xa2"-\'\xe2\x96\xa0s \n\nThe weight lost by the produce of one acre in \n\ndrying .,..--- \n\n64 dr. of grass afford of nutritive matter 3 dr. ^ \nThe produce of the space, ditto - 17.1 dr. S \n\nAt the time the seed is ripe, the produce is \n\n\n\n250470 \n106448 \n\n\n\nor lbs. per aci-e \n=15654 6 \n\n= 6653 8 \n\n\n\n9000 14 \n11740 12 = 733 12 12 \n\n\n\nlr.$ \n\n\n\n239580 \n131769 \n\n\n\n44973 \n= 8235 \n\n\n\n18717 \n\n\n\n6738 \n1169 \n\n\n\nGrass, 22 oz. The produce per acre \n\n80 (/r. of grass weigh when dry - 44 dr. \n\nThe produce of the soace, ditto 193.2 <// \n\nThe weight lost by the produce of one acre in \ndrying ...--.- \n\n64 dr. of grass afford of nutritive matter 5dr \n\nThe produce of tl>e space, ditto 27.2 dr \n\nThe weight of nutritive matter which is lost by taking the crop \n\nat tlie time of flowering, exceeding one-third part of its value is 436 1 3 \nTlie proportional value which the gra.ss, at the time of flowering, bears to \n\nthat at the time the seed is ripe, is as 12 to 20. \n\nThe i-Toduce of latter-math is \n\nGrass, 7 oz. The produce per acre - - 76230 = 4764 6 \n\n64 </r. of grass afford of nutritive matter 1.2 dr. J 786 10 = 111 10 10 \n\n\n\nAPPENDIX. 285 \n\nThe proportional value which the g^rass of the latter-math bears to that at \nthe time of ilowering, is as 6 to 12, and to that at the time the seed is ripe, as \n6 to 2U. \n\nLXVIII. Cynomnis ernciefurmis. Beckmannia erucasformis. Host. G. A. 3, \nt. 6. \xe2\x96\xa0 \n\nLinear spiked dog\'s-tail grass, ^at. of Germany. \n\nAt the time the seed is ripe the produce is \n\noz. or //w. per acre \n\nGrass, 18 oz. The produce per acre - - 196020 =12261 4 \n80 f/r. of grass wcisfh when dry - 36 dr. \') ooor.n n \' eei\'^ i a \nine produce of the space, ditto 129. -y 3 \n\nThe weight lost by the produce of one acre in \n\ndryii.g 6738 3 \n\n64 (/r. of grass afford of nutri\'ive matter* 3.1 \xc2\xab\'\'\xe2\x96\xa0\xe2\x80\xa2 "/ qc;^ 9 _ r99 9 9 \nThe produce ofthe space, ditto 14.2| 5 " ~ \n\nLXIX. PMeiim nodosum. W. B. 2, P. 118. \n\nBulbous stalked cat\'s-tail grass. Nat. of Britain. \n\nAt the time of flowering, the produce from a clayey loam, is \n\noz . or lbs. per acre \n\nGrass, 18 or. The produce per acre - - 196020 0=12251 4 \n\n80 c/r. of -grass weigh when dry - 38rf\'-? \'jqiq < \xc2\xab \n\nThe produce of the space, ditto 136| 5 ^^ 8 = 5819 5 S \nThe weight lost by the produce of one acre in \n\ndrjing . 6431 14 8 \n\n64 f/r. of grass afford of nutritive matter 2.2 f/r.^ yA^r n _ 4~\xc2\xab Q n \n\nThe produce of the space, ditto ll.lJr.5 4^0 ^ u \n\nThis grass is inferior in many respects to the Phleum pratense. It is sparing- \nly found in meadows. From the number of bulbs which grow out ofthe straws, \na greater portion of nutritive matter might have been expected. This seems \nto prove, that these bulbs do not form so valuable a part of t\'.e plant as the joints,, \nwliicli are so conspicuous in the Phlevm pratense, the nutritive powers of whicb \nexceed those of the P. nodosum, as 8 to 28. \n\nLXX. Pldeum pratense. Wither. 2. P. 117. \n\nMeadow cat\'s tail grass Nat. of Britain, \n\nAt the time of flowering, the produce from a clayey loam. Is \n\nGrass, 60 or. The produce per acre \n80 dr. of grass weigh when dry - 34 dr. \xe2\x96\xa0? \n\nThe produce of the space, ditto - 408 dr. 3 \n\nThe vveigiit lost by the produce of one acre in \n\ndrying . - \n\n64 dr. of grass afford of nutritive matter 2.2 dr. ) \nTlie produce ofthe space, ditto 37.2 dr. 5 \n\nThe weight of nutritive matter which is lost by leaving the crop \n\ntill the seed be ripe, exceeding one-half of its value - 2073 11 \n\nAt the time the seed is ripe the produce is \n\nGrass, 60 oz. The produce per acre - \xe2\x80\xa2 643400 =40837 8 \n\n80 Jr. of grass weigh when dry - 28 dr.-) \xe2\x80\x9e,03fi5 10^.07 T? n \n\nThe produce of the space, ditto ^:\'b dr.S 0=19^97 13 \nThe weight lost by the produce of one acre in \n\ndrying . - 21439 11 e \n\n\n\noz. \n653400 \n\n\nor lbs. per acre \n=40837 8 \n\n\n277695 \n\n\n= 17355 15 \n\n\n. \n\n\n23481 9 \n\n\n25523 7 \n\n\n= 1595 3 \n\n\n\n286 \n\n\n\nAPPENDIX. \n\n\n\noz. or lbs. per acre \n\n64 Jr of ffrass afford of nutritive matter 5.3 dr \') ^\xe2\x80\x94..^ ,j \xe2\x80\x9e^,a ,^ ,^ \nTh\xc2\xa3 produce of the space, ditto . 86.1 dr.^ ^^\'^"^ ^* == 3b68 15 14 \n\nThe produce of latter math is \n\nGrass, 14 oz The produce per acre - - 152460 = 95^28 12 \n64 (/r. of grass afford of nutritive matter 2 dr 4764 6 = 297 12 6 \n\n64 dr: of the straws affoid of nutritive matttrr 7 dr. The nutritive powers of \nthe straws slm]3ly, therefore, exceed those of tiie leaves, in proportion as 28 \nto 8 ; and the grass at the rime of flower. ng-. to t..at at the time the seed is \nripe, as lU to 23 ; and the latter math to tlie grass of the flowering crop, us 8 \nto 10. . \n\nThe comparative merits of this grass will appear, from the above particulars, \nto bd very great; to which may be added the aiitindance of tine foliage tha\' it \nproduces early in the spring. In this respect it is inferior to the Fou JevtHis, \nand Poa ang^isitfoHa only. The value of tlie straws at the time the seed is \nripe, exceeds that of the grass at the time of flowering, as 28 to 10 ; a circnm- \nstance v/hich increases its value above many others; for, by this projx\'rt} , its \nvaluable early foliage may be cropped, to an ad\\anced period of the season, \nwithout injury to the crop of hay, which, in other grasses which send I\'orth \ntheir flowering straws early in the season, would cause a loss of nearly one-half \nof the value of the crop, as is clearly proved by former examples ; and -his \nproperty of the straws, makes the plant peculiarly valuable for the purpose \nof hay. \n\n\n\nLXXI. PMeum pratense. Var, minor. Wither. B. 2, 118. Var. 1. \nMeadow cat\'s-tail grass. Var. Smaller. Nat. of Britain. \n\nAt the time of ripening the seed, the produce from a clayey loam, is \n\n\n\n\xe2\x96\xa0\\ \n\n\n\nGrass. 40 oz. The produce per acre \n\n80 dr of grass weigh when dry - 34 dr. \n\nThe produce of the space, ditto 272 dr. \n\nThe weight lost by the produce of one acre in \n\ndrying \n\n64 dr. of grass afford of nutritive matter 2.3 dr. \n\nThe produce of the space, ditto 272 dr \n\nThe produce of latter-math is, \nGrass, 14 or. The produce per acre \n\n64 dr. of grass afford of nutritive matter 1.2 dr. \n\n\n\noz. \n\n435600 \n\n\nor lbs. per acre \n=27225 \n\n\n185130 \n\n\n=11570 10 \n\n\n\n\n\n. \n\n\n15654 6 \n\n\n\n\n\n1817 \n\n\n3 = 1169 13 \n\n\n3 \n\n\n152460 \n3573 \n\n\n= 9528 12 \n4 = 223 5 \n\n\n\n4 \n\n\n\nLXXII. FAymus arenarivs. Engl. Bot. 1672. \n\nUpright sea lyme grass. Nat. of Britain \n\nAt the time the seed is ripe, the produce from a clayey loam, is \n\n\n\nGrass, 64 oz. The produce per acre \n80 dr. of grass weigh when thy \xe2\x80\xa2 , 45 dr. I \n\nThe produce of the space, ditto \xe2\x80\xa2 576 dr. 5 \n\nThe weight lost by the produce of one acre in \n\ndrying \n\n64 dr. of grass afford of nutritive matter 5 \n\nThe produce of the space, ditto - 80 \n\n\n\n696960 \n392040 \n\n\n\ndr.1 \ndr.S \n\n\n\n54450 \n\n\n\nor /6s. per acre \n=43560 \n\n=24502 8 \n\n\n\n18957 \n= 3403 \n\n\n\nLXXIII. Elymus geniculatus. Pendulous 13\'me grass. Engl. Bot. 15S6. \nPendulous sea lyme grass. Nat. of England, \n\n\n\nAPPENDIX. \n\n\n\n287 \n\n\n\nAt tlie time of flowering, the produce from a sandy soil, is \n\n\n\nGrass, 30 oz. The produce per acre \n80 dr of grass weigh when dry - 32 Jr. ^ \n\nTlic produce of the space, ditto 192 dr. 3 \n\nI\'he weight lost by the produce of one acre in \ndryuig \n\n\n\noz. or lbs. per acre \n\n326r00 =20418 12 \n\nI0O68O = 8167 8 \n\n\n\n64 df. of grass afford of nutritive matter 3.1 dr.\\ \nThe produce of the sp.ice, ditto 24.1^ 5 \n\n\n\n16590 \n\n\n\n12251 4 \n= 1036 14 \n\n\n\nLXXIV. Bromus inermis. Host. G. A. 1, t. 9. \n\nAwnless brome gTass. Nat. of Germany, \nneman in 1794. \n\n\n\nIntroduced by Mr. Ilua- \n\n\n\nAt the time the seed is ripe, tlie produce from a black sandy soil, is \n\n\n\nt;l \n\n\n\nGrass, 18 oz. The produce per acre \n80 (//\xe2\x80\xa2. of grass weigh when dry 35 dr. \n\nThe produce of the space, ditto 126 c?; \n\nThe weight lost by the produce of one acre in \n\ndrying- \n\n64 dr. of grass afford of nutritive matter 4 1 dr. \'> \nThe produce of the space, ditto l^-\'Jy 3 \n\nThe produce of latter-math is \n\nGrass, 13 oz. Tlie produce per acre \n\n64 dr. of grass afford of nutritive matter 1.1 dr. \n\n\n\noz. \n196020 \n\n\nor lbs. per acre \n= 12251 4 \n\n\n85758 12 \n\n\n== 5359 14 12 \n\n\n. \n\n\n6891 5 4 \n\n\n13016 15 \n\n\n= 813 8 15 \n\n\n141570 \n2765 \n\n\n= 8848 2 \n= 172 13 \n\n\n\nLXXV. .^igrostis vulgaris. Wither. Bot. 2, 132. Hud. A. capllaris. Dr. Smithy \nA. arenaria. \nFme bent grass. Nat. of. Britain. \n\n\n\nAt the time the seed is ripe, the produce from a sandy soil, is \n\n\n\n152460 \n76230 \n\n\n\nor lbs per acre \n= 9528 12 \n\n\n\n4764 6 \n\n\n\n.2^%dr.l \n\n\n\n4019 15 \n\n\n\n4764 \n251 \n\n\n\n6 \n3 15 \n\n\n\nGrass, 14 oz. The produce per acre \n80 dr. of grass weigh when dry - 40 dr. \n\nThe produce of the space, ditto 112 dr. \n\nThe weight lost by the produce of one acre in \n\ndrying \n64 dr. of grass afford of nutritive matter 1.2-^ \nThe produce of the space, ditto 5 \n\nThis is one of the most common of the bents, likewise the earliest; in these \nrespects, it is superior to all others of the same family, but inferior to seveml \nof them in produce, and the quantity of nutritive matter it affords. As the \nspecies of this f:\\mily are generally rejected by the cultivator, on account of the \nlateness of their flowering ; and this circumstance, as has alreadj\' been obser- \nved, does not always imply a proportional lateness of foliage, their compara- \ntive merits in this respect may be better seen, by bringing them into one vieWj \nas to the value of tiieif early foliage. \n\n\n\nThe \n\n\naj>parept difference \n\n\nTlieir nutritive \n\n\n\n\nof time. \n\n\npowers. \n\n\nAgrostis vulgaris \n\n\nMiddle of April \n\n\n- 1-2^ \n\n\npalustris \n\n\nOne weel;\' later \n\n\n- 2.3^ \n\n\nsiolonifera \n\n\nTwo, ditto \n\n\n- 3.2 \n\n\ncanina \n\n\nDitto, ditto \n\n\n1.3 \n\n\n\xe2\x96\xa0itricia \n\n\nDitto, ditto \n\n\n\' 1.2 \n\n\n\n288 APPENDIX. \n\n\n\nThe apiiarenl \n\n\n\xe2\x96\xa0 difference \n\n\nTheir nutritive \n\n\n(if time. \n\n\n\n\n\n\njjoweis. \n\n\nnivea Tliree \n\n\nweeks, \n\n\nditto \n\n\n2 \n\n\nlittoralis Ditto, \n\n\n\n\nditto \n\n\no \n\n\nrepcns Ditto, \n\n\n\n\nditto \n\n\no \n\n\nmt\'xicana Ditto, \n\n\n\n\nditto \n\n\n2 \n\n\nfasciculans Ditto, \n\n\n\n\nditto \n\n\n2 \n\n\n\nT.XXVI. Agrostis palmtns. Wither. Bot. 2, P. 129. Var. 2, alba. Engl. Bot. \n1189. A. alba. \nMarsh bent grass. \n\nAt tlie time of flowering\', the produce from a bog-earth, is \n\noz. or lbs. per acre \n\nGrass, 15 or. The produce per acre - - 163350 6 =102u9 6 \n80 f/r. of errass weiHi when dry 36 dr.\') ,-.-,, n\'r q ,itn.t o o \n\nThe produce ot the space ditto - lOo dr.^ \nTlie weight lost by the produce of one acre in \n\ndrying -.....:..- 5615 2 3 \n\n64 Jr of grass afford of nutritive matter 2.3 rfr. > 7018 15 = 4""? 10 15 \nThe produce of the space, ditto - 10. H 3 _ a \n\nAt the time the seed is ripe the produce is \nGrass, 20 oz. The produce per acre - - - 217800 =13612 8 \n80 rfr. of grass weigh when dry 32rf..J ^ = 5445 \n\nThe produce 01 the space, ditto 128 dv.$ \n\nThe weight lost by the produce of one acre in \n\ndrying 8167 8 \n\n64 f/?\'. of grass afford of nutritive matter 2.j dr.\') q"\\q q _ \'>P4 14. Q \n\nThe produce of the space, ditto 13 3 dr. 5 ^ ~ \n\nThe weight of nutritive matter which is lost by taking the crop at \n\ntlie time of flowering, being one-fourth part of its value - 146 3 10 \n\nThe proportional value of grass, in each crop is equal. \n\nT.XXVII. Panicum dactijhm. Engl. Bot. 850. Host. G. A. 2, t. IS. \nCreeping Panic grass. Nat. of Britain. \n\nAt the time of flowering, the produce from a sandy loam, with manure, is \n\noz. or lbs. per acre \n\nfJrass 46 oz. The produce per acre - - 500940 =31308 12 \n\nHi; dr, of grass weigh when dry 36 dr. ") gor^oa \xc2\xab \n\nTlie produce of the space, ditto 33l.0| 5 "^^^^^^^ ^ \n\'I\'he weight lost by the produce of one acre in \n\ndrying -\xe2\x80\xa2 \n\n64 dr. of grass afford of nutritive matter 2 dr. 7 -i rg^x .5 \nThe produce of the space, ditto - 23 dr. $ \n\n\n\n.LXX\\\'ni. Aqmslis utolonifi\'ra. Engl. Bot. 1532. Wither. Bot. 2, 181. (Fiorln, \nl)r. Richardson.) \nCreeping bent. Nat. of Britain. \n\nAt the time of flowering, the produce from a bog soil, is \n\noz. or lbs. per acre \n\nCrass, 26 or. The produce per acre - - 283140 =17696 4 \n\n80 Jr. of grass weigh when dry - .35 Jr.") ,^^07- 10 77.10 1 19 \nThe produce of the space, ditto - i82,/r.5^ \n\n\'>\xe2\x96\xa0\'".\xc2\xa3 weight lost by the jjroducc of one acre - - - 9732 15 O \n\n\n\n14088 15 \n\n\n\n\n\n17219 13 \n\n\n\n\n\n97866 6 \n\n\n\n\n\n\nAPPENDIX. \n\n\n\n289 \n\n\n\n<54 dr. of grass afford of nutritive matter 3.2 dr. \nThe produce of the space, ditto 22.3 dr \n\n\n\n:] \n\n\n\noz. \n15484 \n\n\n\nor lbs. per acre \n= 967 1.2 3 \n\n\n\n36 dr. \n20I.2| \n\n\n\n504920 \n137214 \n\n\n\n=19057 8 \n= 8575 14 \n\n\n\n10481 10 \n16675 = 1042 3 \n\n\n\nAt the time the seed is ripe the produce is \n\nGrass, 28 oz. The produce per acre \n\n80 dr. of grass weigh when dry \n\nI\'he ])roduce of the space, ditto \n\n\'I\'he weight lost by the produce of one acre in \n\ndrying ....... \n\n64 dr. of grass afford of nutritive matter 3.2 di \nThe produce of the space, ditto 24.2 dr \n\nThe weight of nutritive matter which is lost by taking the crop at \n\nthe time of flowering, being nearly one-fourteenth of its value, 74 7 3 \n\nI.XXIX. ^groxtis stolonifera. Var. angnstilblia. \n\nCreeping bent, with narrow leaves. Nat. of Britain. \n\nAt the time the seed is ripe, the produce fnmi a bog soil, is \n\nGrass, 24 oz. The produce per acre \n80 dr. i)f grass weigh when dry 36 dr. > \n\nThe produce of the space, ditto 172.3y 5 \n\nThe weight lost by the produce of one acre in \ndrying ... . . . . . \n\n64 dr. of grass afford of nutritive matter 3 dr. ") \n\nThe produce of the space, ditto 18 dr. 5 \n\nI\'he weight of nutritive matter afforded by tlie produce of one \n\nacre of the Agrostis stolonifera, exceeding that of the variety in \n\nproportion, is 6 to 8 - 276 8 1 \n\nThe above details will assist the farmer in deciding on the comparative va- \nlue of this gi"ass. From a careful examination it will dovibtless appear to pos- \n.sess merits well worthy of attention, though perhaps not so great as has been \nsupposed, if the natural place of its growth and habits be impartially taken \ninto the account. From the couchant nature of this grass, it is denominated \ncouch-grass, by practical men, and from the length of time that it retains the \nvital power, after being taken out of the soil, is called squitch, quick, full of \nlife, &c. \n\nLXXX. Agrostis camia. Engl. Bot. 1856. \nBrown bent. Nat. of Britain. \n\n\n\noz. \n261360 \n\n\nor lbs. per acre \n=16335 \n\n\n117612 \n\n\n= 7350 12 \n\n\n. \n\n\n8984 4 \n\n\n12251 \n\n\n4 = 765 11 4 \n\n\n\nAt the time of flowering, the produce from a brown sandy loam, is \n\n\\i \\ 43013 =- 2688 5 \n\n\n\noz. or /6s. per acre \n\n98ulG = 6125 10 \n\n\n\n\n\n\n3437 \n3828 8 = 239 \n\n\n\nGrass, 9 oi. The produce per acre \n80 dr. of grass weigh when dry 34 dr. \n\nThe produce of the space, ditto - 63-j- . \nThe weight lost by the produce of one acre in \n\ndrying \n\n\'64 dr. of grass afford of nutritive matter 2.2 dr. \\ \nThe produce of the space, ditto - 5.21^ 3 \n\nLXXXI. Agrostis canina. Var. muticae. \n\nAwnless brown bent. Nat. of Britain. \n\nAt the time the seed is ripe, the produce from a sandy soil, is \n\noz. or lbs: per acre \n\nGrass, 21 oz. The produce per acre - ^-- - \n\nO \n\n\n\n228690 =14293 2 \n\n\n\n290 \n\n\n\nAPPENDIX. \n\n\n\nw. \n\n\n\n80 dr. of grass weigh when dry - 24 dr. "> \nThe produce of the space, ditto 100.3-y ^ \n\nThe weight lost by the produce of one acre in \n\ndrying \n\n64t/r. of grass afford of nutritive matter 1.3 dr. ^ \nThe produce of tlie space, ditto - 9.0j 5 \nThe weight of nutritive matter which the produce of one acre of \n\nthe awnless variety, exceeds that of the last mentioned species 151 \n\n\n\n68607 \n\n\n\n6253 \n\n\n\nor lbs. per acre \n= 4287 15 \n\n\n10005 3 \n= 390 13 \n\n\n\n\n\n\n\n8 11 \n\n\n\n1.XXXII. Agrostis stricta. Curt. A. rubra. \n\nUpright bent grass. Nat. of Britain. \n\nAt the time the seed is ripe the produce from a bog soil, is \nGrass, 11 or. The produce per acre - - 119790 = 7486 14 \n80 dr. of grass weigh when dry - 29 dr. "> 43433 ^^ ^ 2713 15 \n\nThe produce 01 the space, ditto - oo* dr.y \n\nThe weight lost by the produce of one acre in \n\ndrj\'ing - 4772 15 \n\n64 dr. of grass afford of nutritive matter 1.2 dr.\\ 0007 o \xe2\x80\x94 it*? r \nThe produce of the space, ditto - * \'\' " ^ "^^^^ ^~ ^\'^ \' \n\n\n\n.2 dr.\\ \n\n\n\nLXXXni. Agrostis nivea. \n\nSnowy bent grass. Nat. of Britain. \n\nAt rhe time the seed is ripe, the produce from a sandy soil, is \n\n\n\nGra-iS, 7 oz. The produce per acre \n80 ./\' . of grass weigh when dry - 22 dr. i \nThe pvoduce of the space, ditto - 30.S-|- 3 \nThe weight lost by the produce of one aci\'e in \n\ndryiig - \n\n64 dr. of grass afford of nutritive matter 2 dr. 7 \nThe produce of the space, ditto - o^dr. 3 \n\n\n\n76230 \n20963 4 \n\n\n\nor lbs. per awe \n= 4764 6 \n\n\n\n1310 3 \n\n\n\n3454 3 \n2382 3 == 148 14 \n\n\n\nLXXXIV. Agrostis fascicularis. ILids. Var. canina. Curt. \nTufted leaved bent. Nat. of Britain. \n\nAt the time of flowering, the produce from a light sandy soil, is \n\n\n\nGrass, 4 oz. The produce per acre \n\n80 ^r. of grass weigh when dry - 20 dr.\') \n\nThe produce of the space, ditto - 16 dr. 5 \n\nThe weight lost by the produce of one acre in \n\ndrying \n\n64 dr. of grass afford of nutritive matter 2 dr. 7 \n\nThe produce of the space, ditto - 2 </r. 3 \n\n\n\n43560 \n10890 \n\n\n\nor lbs. per acre \n= 2722 8 \n\n= 680 10 \n\n\n\n2041 14 \n1361 4 = 85 1 4 \n\n\n\nLXXXV \n\n\n\nFestiica pirmatn. Bromus pinnatus. Engl. Bot. 730. \nSpiked fescue. Nat. of Britain. \n\n\n\nAt the time the seed is ripe, the produce from a light sandy soil, with ma- \nnure, is \n\n\n\nGrass 30 oz. The produce per acre \n\n80 dr of grass weigh when dry - 32 d> \n\nThe produce of the space, ditto - 192 \n\n\n\ndr. I \ndr.^ \n\n\n\noz. or lbs. per acre \n\n326700 \xe2\x80\x9420418 12 \n\n130680 \xc2\xab 8167 8 \n\n\n\nAPPENDIX, 291 \n\n0^, OP lbs. per acre \n\n4:he weiffht lost by tlie produce of one acre in \n\ndrying - - 12251 4 \n\n64 dr. of grass afford of nutritive matter 1.1 dr.\'> g^gn it \xc2\xab. 398 to 13 \nTlie produce of the space, ditto - 9.1 ^ 5 \n\nLXXXVI. Panicum viride. Curt. Lond. Engl. Bot. 875. \nGreen Panic grass. Nat. of Britain. \n\nAt the time the seed is ripe, the produce from a light sandy soil, is \nGrass, 8 oz. The produce per acre - - 87120 = 5445 \n\n80 rfr. of grass weigh when dry - 32 dv.} ^^^^^ Q \xc2\xbb= 2178 \nThe produce or the space, ditto - 51^ 3 \nThe weight lost by the produce of one acre in \n\ndrying 326/ \' \n\n64 Jr. of grass afford of nutritive matter 1.2 dr.") nr, ., ^. iot q i^ \n\nThe produce of the space, ditto - 3 dr. 5 -^^^^ ^^\' \xc2\xb0\xc2\xb0 1-^\' ^ \xe2\x96\xa0^* \n\nLXXXVII. Panicum sanguinale. Curt. Lond. Engl. Bot. 849. \nBlood coloured panic grass. Nat. of Britain. \n\nAt the time the seed is ripe, the produce from a sandy soil, is \n\nGrass, 10 oz. The produce per acre - - 108900 0. = 6806 4 \n64 dr, of grass afford nutritive matter \xe2\x96\xa0\'^\xe2\x80\xa2^\xe2\x96\xa0^g- 1914 4 = 119 IQ 4 \n\nThis and the prec\xc2\xabdmg species are strictly annual, and from tlie results of \nthis trial their nutritive powers appear to be very inconsiderable. The seed \nof this species, Mr. Schreber describes (in Beschreibung der Graser) as the \nmanna grass. In Poland, Lithuania, 8tc. it is collected in great abundance when \nafter being thoroughly separated from the husks, it is fit for use. When boil- \ned with milk, or wine, it forms an extremely palatable food, and is most com- \nmonly made use of wliole, in the manner of sago, to which it is in general pre. \nferred. \n\nLXXX^^II. Agrostis lobata. Curtis, lobata carenai\'ia, \nLobed bent grass. \n\nAt the time of flowering, the produce from a sandy soil, is \n\n0-. or ibs. per acfe \n\nGrass, 10 oz. The produce per acre - - 108900 = 6806 4 \n80 dr. of grass weigh when dry - - 40 dr. "> \n\nThe produce of the space, ditto - -BOdr.S ^4450 = 3403 2 \nTlie weight lost by the pi\'oduce of one acre in \n\ndrying -".-.-.-... 3403 2 \n\n64 dr. of grass afford of nutritive matter 3 dr.\\ ,.,\xe2\x80\x9e. ., _ ^ \n\nThe produce of the space, ditto - 7.2dr,S ^^"* ^^ -^ -^^^ ^ 1^ \n\nLXXXIX. Agrostis repens. Whitlier. Bot. A. nigra. \n\nCreeping rooted bent, black bent. Nat. of Britain. \n\nAt the time of flowering the produce from u clayey loam, is \n\noz. or lbs. per acr^e \n\nGrass, 9 oz. The produce per acre - - 98010 = 6125 10 \n\n80 dr. of grass weigh when dry - - 35 dr. > Acyom e. o\xc2\xab-q 1 \xc2\xab \xe2\x80\xa2; \n\nThe produce ofthe space, ditto - -63 d;. 5 ^^^^ 6=26/9 15 6 \nThe weiglit lost by the produce of one acre in \n\ndrying 3445 \\Q IQ \n\n64 rfc. of grass afford of nutritive matter 3 dr. \\ >\xe2\x96\xa0\xc2\xa3\xe2\x96\xa0\xc2\xab o 00^ a \xc2\xab \n\nThe produce of the space, ditto - 6.3 dr. $ \'*^594 o = 287 3 o \n\n\n\n304920 \n\n\n= 19057 \n\n\n8 \n\n\n106722 \n\n\n= 670 \n\n\n2 \n\n\n- \n\n\n12387 \n\n\n6 \n\n\n9528 12 \n\n\n595 \n\n\n8 12 \n\n\n\n292 APPENDIX. \n\nXC. Jgrontis JMexicana. Hort. Kew. 1. P. 150. \n\nMexican bent grass. Nat. of S. America. Introduced, 1780, by M. tl \nAlexander. \n\nAt the time of flowering, the produce from a black sandy soil, is \n\noz. or lbs. per acre \n\nGrass, 28 oz. The produce per acre \n80 dr. of grass weigli when dry - 28 \'^r. ~i \n\nThe produce of the space, ditto - 156.33- 5 \nThe weight lost by the produce of one acre in \n\ndrying - \n\n64 dr. of grass afford of nutritive matter 2 dr. \\ \nThe produce of the space, ditto - - 14 c/r 5 \n\nXCI. Stipa pennata. Eng. Bot. 1356. \n\n- Long-awned feather gi-ass. Nat. of Britain. \n\nAt the time of flowering, the produce from a heath soil is \n\nor. or lbs. per acre \n\nGrass, 14 oz. The produce per acre - - 152460 = 9528 12 \n\n80 Jr. of grass weigh when diy - \'- 29 f\'?\'. 1 ,.o/;<; ,\xc2\xab ^aha o io \n\nThe produce of thi space, ditto - 81 } 5 ^^^66 12 = 3454 2 12 \nThe weight lost by the produce of one acre in \n\ndrying - . . . . 6074 9 4 \n\n64 f/r. of grass afford of nutritive matter 2.3 dr. 7 .^ ac\\q t n \n\nThe produce of the space, ditto - 9.2^ 3 0^51 u \xe2\x80\x94 4uy 7 U \n\nXCII. Triticiim repens. Engl. Bot. 909. \n\nCreeping rooted wheat grass. Nat. of Bi\'itain. \n\nAt the time of flowering, the produce from a light clayey loam is \n\nor. or lbs. per acre \n\nGrass, 18 oz. The produce per acre \n80 dr. of grass weigh when clry - 32 \'\'f. ") \n\nThe produce of the space, ditto - 115j- 3 \nThe weight lost by the produce of one acre in \ndrying -.--... \n\n64 dr. of grass afford of nutritive matter 2 dr. \\ \nThe produce of the space, ditto - - 9 </r. > \n64 dr. of the roots, afford of nutritive matter 5.\'i dr. The proportional value \nof the roots, is therefore to that of the grass, as 23 to 8. \n\nXCin. Mopecunts ngrostis. Engl. Bot. 848. A. myosuroides. \nSlender fox-tail grass. Nat. of Bi-itain, Curt. Lond. \n\nAt the time of flowering, the produce from a light sandy loam is \n\noz. or lbs. per acre \n\nGrass, 12 oz. The produce per acre - - 130680 = 8167 8 \n\n80 c/r. of grass weigh when dry - - ol *0 "ira ia r \n\nThe produce of the space, ditto - 74.l| 5 ^"^\'^^ ^ ~ ""^^^ ^* ^ \n\n64 Jr. of grass afford of nutritive matter 1.3 Jr. > _,._\xe2\x80\x9e . \xe2\x80\x9e\xe2\x80\x9e,-, - . \n\nThe produce of the space, ditto - 5.1 Jr. 3 \'^^\'\'^ \' \'^\'^\'^ ^ * \n\nXCIV. Bromus asper. Engl. Bot. 1172. Curt. Lond. Bromus hirsutus. H\xc2\xabds. \nBromus ramosus. B. sylvaticus, volger. B. altissimus. \nH^ry stalked brome grass. Nat. of Britain. \n\n\n\n196020 \n\n\n= 12251 4 \n\n\n78408 \n\n\n= 4900 8 \n\n\n- \n\n\n. 7350. 12 \n\n\n6125 10 \n\n\n= 382 13 10 \n\n\n\nor. \n\n\n\n\nor lbs. per acre \n\n\n217800 \n\n\n\n\n\n=,13612 8 \n\n\n65340 \n\n\n\n\n\n=. 4083 12 \n\n\n- \n\n\n\n\n9528 12 \n\n\n6806 \n\n\n4 \n\n\n= 425 6 4 \n\n\n\n871200 =54450 \n416 J:} 283177 8 =17697 \n\n\n\n9 8 \n\n\n- 36752 \n-30rt:| ^0418 12 = 1876 \n\n\n6 6 \n\n2 12 \n\n\n\nAPPENDIX. - 293 \n\nAt the time of flowering the produce from a light sandy soil, is \n\nGrass, 20 oz. The produce per acre \n80 dr of grass weigh when dry - - 24 dr. > \nThe produce of the space, ditto - - 96 dr. ^ \nThe weight lost by the produce of one acre in \n\ndrying ..----. \n\n64 dr. of grass afford of nutritive matter 2 dr. \nThe produce of the space, ditto 10 dr. \n\nXCV. Phalaris canardensis. Engl. Bot. 1310. \nCommon Canary grass. Nat. of Britain. \n\nAt the time of flowering, the produce from a clayey loam, is \n\noz. or lbs. per acre \n\nGrass, 80 oz. The produce per acre \n80 dr. of grass weigh when dry \nThe produce of the space, ditto \nThe produce in weight lost by drying \n64 dr. of grass afford of nutritive matter \nThe produce of the space, ditto \n\nXCVI. MeUca ccernlea. Curt. Lond. Engl. Bot. 750. \nPurple Melic grass, Nat. of Britain. \n\nAt the time of flowering, the produce from a light sandy soil, is \n\noz or lbs, per acre \n\nGrass, 11 or. The produce per acre - 119790 = 7486 14 Q \n\n80 dr. of grass weigh when dry - - 30 dr.\') \n\nThe produce of the space, ditto - \xe2\x80\xa2 66 dr. 5 ^^^^l 4 -= 2807 9 4 \nThe weight lost by the produce of one acre in \n\ndrying 4679 4 3 \n\n64 Jr. of gi\'ass afford of nutritive matter 1.2 rf^o 07?/- o \n\nThe produce of the space, ditto \xe2\x96\xa0- 4.0| J ^\'^^ " =" I\'^S 4 8 \n\nXCVII. Dactylis cynosuroides. Linn. fil. fasci. 1. P. 17. \n\nAmerican cock\'s foot grass. Nat. of N. America, \n\nAt the time of flowering, the produce from a clayey loam, is \n\noz. or lbs. per acre \n\nGrass, 102 oz. The produce per acre - ^ 111780 =69423 1 \n\n80 rfr. of errass weiffh when dry - -48 ^ cccAro n a-^^. . \n\nThe produce of thi space, ditto - 979^ ^ ^^6468 =41654 4 \nThe weight lost by the produce of one acre in \n\ndrying - - - 27769 8 \n\n64 Jr. of grass afford of nutritive matter 1.3 rfr.l on\'^\'o n lono a \n\nThe produce of the space, ditto - 44.2| 3 \'" u = I6y8 4 \n\nOf the Time in lohich different Grasses produce Flowers and Seeds. \n\nTo decide positively the exact period or season, when a grass always comef; \ninto flower, and perfects its seed, will be found impracticable ; for a variety of \ncircumstances interfere. Each species seems to possess a peculiar life in \nwhich various periods may be distinctly marked, according to the varieties of \nits age, of the seasons, soils, exposure, and mode of culture. \n\nThe following Table, which shews the time of flowering, and the time \nof ripening the seed of those grasses growing at Woburn, which are meu\' \ntioned in the Experiments, must therefore only be considered as serving for \na test of comparison, for the different grasses, growing under the same qircum- \nstances. \n\n\n\n294 \n\n\n\nAPPENDIX. \n\n\n\nr^ \n\n\n\nTime of flowering. \n\n\n\nTime of ripeitiog the \nSeed. \n\n\n\nAnthoxant\'mim odoratum \n\nllolcusodoratus - \n\nCynosurus caeruleus - \n\nAlopecurus pratensis \n\nAlopecurus aipinus \n\nPoa alpina \n\nPoa pratensis \n\nPoa cserulea \n\nAvena pubescens \n\nFestuca hordiformis \n\nPoa trivialis - \n\nFestuca g-lauca \n\nFestuca glabra \n\nFestuca rubra \xe2\x80\xa2 \n\nFestuca ovina \n\nBriza Media \n\nDactylus glomerata \n\nBromus tectorum \n\nFestuca oambrica \n\nBromus diandrus - \n\nPoa angustifblia \n\nAvena elatior \n\nPoa elatior \n\nFestuca duriuscula \n\nMilium etl\'usum \n\nFestuca pratensis \n\nLolium perenne \n\nCynosurus cristatus \n\nAvena pratensis \n\nBromus multiflorus \n\nFestuca loliacea \n\nPoa cristata \n\nFestuca myurus \n\nAira flexuosa \n\nHordeum bulbosum - \n\nFestuca calamaria \n\nBromus littoreus \nFestuca elatior \nNardus stricta \nTriticum, (species of) \nFestuca fluitans \nFestuca dumctorum \nHolcus lanatus \nPoa fertilis \nArundo colorata \nPoa (species of) - \nCynosurus erucseforniis \nPlileum nodosum \nPhleuni protcnse \nElymus arenarius \nElyinus geniculatus \nTrifolium pratense \nTrifolium pratense \xc2\xab^ \nTrifoliiim niacrorhi/.UTP \nSanguisorba canadensis \nBunias oricntalis - \nMedicago sativa \nHedysaruni onobrychis \n\n\n\n20 \n30 \n\n\n\nApril 29 \n\nApril 29- \n\nApril 30 \n\nMay 20 \n\nMay \n\nMay \n\nMay 30 \n\nftlay 30 \n\nJune 13 \n\nJune 13 \n\nJune 13 \n\nJune 13 \n\nJune 16 \n\nJune 20 \n\nJune 24 \n\nJune 24 \n\nJune 24 \n\nJune 24 \n\nJune 28 \n\nJune 28 \n\nJune 28 \n\nJune 28 \n\nJune 28 \n\nJuly \n\nJuly \n\nJuly \n\nJuly \n\nJuly \n\nJuly \n\nJuly \n\nJuly \n\nJuly \n\nJuly \n\nJuly \n\nJuly \n\nJuly \n\nJuly \n\nJuly \n\nJuly \n\nJuly \n\nJuly \n\nJuly \n\nJuly \n\nJuly \n\nJuly \n\nJuly \n\nJuly \n\nJuly \n\nJuly \n\nJulv \n\nJuly- \nJuly \n\nJuly \n\nJuly \n\nJuly \n\nJuly \n\nJuly \n\nJii]v \n\n\n\nJune \n\n\n21 \n\n\nJune \n\n\n25 \n\n\nJune \n\n\n20 \n\n\nJune \n\n\n24 \n\n\nJune \n\n\n24 \n\n\nJune \n\n\n30 \n\n\nJuly \n\n\n14 \n\n\nJuly \n\n\n14 \n\n\nJuly \n\n\n8 \n\n\nJuly \n\n\n10 \n\n\nJuly \n\n\n10 \n\n\nJuly \n\n\n10 \n\n\nJuly \n\n\n10 \n\n\nJuly \n\n\n10 \n\n\nJuly \n\n\n10 \n\n\nJuly \n\n\n10 \n\n\nJuly \n\n\n14 \n\n\nJuly \n\n\n16 \n\n\nJuly \n\n\n16 \n\n\nJuly \n\n\n16 \n\n\nJuly \n\n\n16 \n\n\nJuly \n\n\n16 \n\n\nJuly \n\n\n16 \n\n\nJuly \n\n\n20 \n\n\nJuly \n\n\n20 \n\n\nJuly \n\n\n20 \n\n\nJuly \n\n\n20 \n\n\nJuly \n\n\n28 \n\n\nJuly \n\n\n20 \n\n\nJuly \n\n\n28 \n\n\nJuly \n\n\n28 \n\n\nJuly \n\n\n28 \n\n\nJuly \n\n\n28 \n\n\nJuly \n\n\n28 \n\n\nJuly \n\n\n28 \n\n\nJuly \n\n\n28 \n\n\nAug. \n\n\n6 \n\n\nAug. \n\n\n6 \n\n\nAug. \n\n\nb \n\n\nAug. \n\n\n10 \n\n\nAug. \n\n\n12 \n\n\nJuly \n\n\n20 \n\n\nJuly \n\n\n26 \n\n\nJuly \n\n\n28 \n\n\nJuly \n\n\n28 \n\n\nJuly \n\n\n30 \n\n\nJuly \n\n\n30 \n\n\nJuly \n\n\n30 \n\n\nJuly \n\n\n30 \n\n\nJuly \n\n\n30 \n\n\nJuly \n\n\n30 \n\n\nJuly \n\n\n30 \n\n\nJuly \n\n\n30 \n\n\nJuly \n\n\n30 \n\n\nJuly \n\n\n30 \n\n\nJuly \n\n\n30 \n\n\nAug \n\n\n6 \n\n\n\nAug. \n\n\n\nAPPENDIX. \n\n\n\n295 \n\n\n\nHordeum pratense \nPoa compressa \nPoa aqiiatica - \nRromus cristatus - \nElymus sibiricus \nAira csespitosa \nAvena flavescens \nBromus sterilis \nHolcus mollis - . \n\nBromus inermis - \nAijrostis vulgaris \nAgrostis palustris \nPanicum dactylon \nAgrostis stolonifera \nAgrostis stolonifera (var.) \nAgrostis canica \nAgrostis stricta \nFestuca pennata \nPanicum viride \nPanicum sanguinale - \nAgrostis lobata \nAgrostis repens \nAgrostis fascicularis \nAgrostis nivea - \nTriticum repens - \nAlopecurus agrestis \nBromus asper \nAgrostis mexicana \nStipa pennata - \nMelica caerulea \nPhalaris cananiensis \nDactylus cynosuroidcs\' \n\n\n\nTime of flowerinp. \n\n\n\nJuly 20 \nJuly 20 \nJulv 20 \nJuly 24 \nJuly \'24 \nJuly 24 \nJulv 24 \nJuly 24 \nJuly 24 \nJuly 24 \nJuly 24 \nJuly 28 \nJuly 28 \nJuly 28 \nJuly 28 \nJuly 28 \nJuly 28 \nJuly 28 \nAug. 2 \nAug. 6 \nAug. 6 \nAug. 8 \nAug. 10 \nAug. 10 \nAug. 10 \nAug 10 \nAug. 10 \nAug. 15 \nAug. 15 \nAug. 20 \nAug. .30 \nAug. 30 \n\n\n\nTime of ripeniiifr the \n\n\nSeed \n\n\n\n\nAug. \n\n\n8 \n\n\nAug. \n\n\n8 \n\n\nAug. \n\n\n8 \n\n\nAug. \n\n\n10 \n\n\nAug. \n\n\n10 \n\n\nAug. \n\n\n10 \n\n\nAug \n\n\n15 \n\n\nAug. \n\n\n20 \n\n\nAug. \n\n\n20 \n\n\nAug. \n\n\n20 \n\n\nAug. \n\n\n\xe2\x80\xa220 \n\n\nAug. \n\n\n28 \n\n\nAug. \n\n\n28 \n\n\nAug. \n\n\n28 \n\n\nAug. \n\n\n28 \n\n\nAug. \n\n\n28 \n\n\nAug. \n\n\n30 \n\n\nAug. \n\n\n30 \n\n\nAug. \n\n\n15 \n\n\nAug. \n\n\n20 \n\n\nAug. \n\n\n20 \n\n\nAug. \n\n\n25 \n\n\nAug. \n\n\n30 \n\n\nAug. \n\n\n30 \n\n\nAug. \n\n\n30 \n\n\nSept \n\n\n8 \n\n\nSept \n\n\n10 \n\n\nSept \n\n\n25 \n\n\nSept \n\n\n25 \n\n\nSept \n\n\n30 \n\n\nSepi \n\n\n30 \n\n\nOct. \n\n\n20 \n\n\n\n* In the experiments made on the quantity of nutritive matter in the \ngrasses, cut at the time the seed was ripe, the seeds were always separa- \nted ; and the calculations for nutritive matter, as is evident from the de- \ntails, made for grass and not hay. \n\n\n\nOf the different Soils referred to in the Appendix. \n\nIv books on agriculture and gardening much uncertainty and confusion \narises from the want of regular definitions of the various soils, to distinguish, \nthem specifically by the names generally used : thus the term bog-earth, is \nalmost constantly confounded with peat-moss, and heath-soil ; also the term \n\xe2\x80\xa2 light loam,\' * heavy soil,\' &c. are given, without distinguishing whether that \nbe \' light\' from sand, or this \xe2\x80\xa2 heavy\' from clay In minute experiments, it is \ndoubtless of consequence to be as explicit as possible in those particulars. \nThe following short descriptions of such soils as are mentioned in the details \nof the experiment are here given for the above purpose. \n\n1st. By \' loam\' is meant any of the earths combined with decayed animail, \nor vegetable mattter. \n\n2nd. \' Clayey-loam,\' when the greatest proportion is clay. \n\nord. \' Sandy-loam\' when the greatest proportion is sand. \n\n4th. \'Brown-loam\' when the greatest proportion consists of decayed vege- \n*able matter. \n\n5th, \' Rich-black loam,\' when sand, clay, animal and veg\'ctable matters are \n\n\n\n296 APPENDIX. \n\ncombined in unequal proportions, the clay greatly divided, being in the least \nproportion, and the sand and vegetable matter in the greatest. \n\nThe terms \' light sandy soil,\' \' light brown loam,\' ^c. are varieties of the \nabove, as expressed. \n\nObservations on the chemical Compositions of the nutritive ^fatter afforded by the \nGrasses in their different States. By t/ie Editor. \n\nX HAVE made experiments on most of the soluble products supposed to con- \ntain the nutritive matter of the grasses, obtained by Mr. Sinclair ; and 1 have \nanalysed a few of them. Minute details on this subject would bt- little inter- \nesting to tlie agriculturist, and would occupy a considerable space ; 1 shall \ntherefore content myself with mentioning some particular facts, and some ge- \nneral conclusions, which may tend to elucidate the inquiry respecting the fit- \nness of the different grasses for permanent pasture, or for alternation, as grecu \ncrops with grain. \n\nThe only substances which I have detected in the soluble matters procured \nfrom the grasses, are mucilage, sugar, bitter extract, a substance analogous to \nalbumen, and diflferent saline matters. Some of the products from the after- \nmath crops gave feeble indications of the tanning principle. \n\nThe order in which these are nutritive has been mentioned in the First \nLecture ; the albumen, sugar, and mucilage, probably wlien cattle feed on \ngrass or hay, are for the most part retained in the body of the animal ; and the \nbitter principle, extract, saline maiter, and tunnin, when any exist, probably \nfor the most part voided in the excrement, with the woody fibi-e. The ex- \ntractive matter obtained by boiling the fresh dung of cows, is extremely similar \nin chemical characters to that existing in the soluble products from the grasses. \nAnd some extract, obtained by Mr. Sinclair, from the dung of sheep and of \ndeer, which had been feeding upon the Lolium perenne, Dactylis glomerata, \nand Trifolium repens, had quahties so analogous to those of the extractive \nmatters obtained from the leaves of the grasses, that they might be mistaken \nfor each other. The extract of the dung, after being kept for some weeks, had \nstill the odour of hay. Suspecting that some undigested grass might have re- \nmained in the dung, which might have furnished mucilage anc\' sugar, as well \nas bitter extract, 1 examined the soluble matter very carefully for these sub- \nstances. It did not yield an atom of sugar, and scarcely a sensible quantity of \nmucilage. \n\nMr. Sinclair, in comparing the quantities of soluble matter afforded by the \nmixed leaves of the Lolium perenne, Dactylis glomerata, and Trifolium repens, \nand that obtained from the dung of cattle fed upon them, found their relative \nproportions as 50 to 13 \n\nIt appears probable from these facts, that the bitter extract, though soluble \nin a large quantity of water, is very little nutritive ; but probably it serves the \npurpose of preventing, to a certain extent, the fermentation of the other ve- \ngetable matters, or in modifying or assisting the function of digestion, and may \nthus be of considerable use in forming a constituent part of the food of cattle. \nA small quantity of bitter extract and saline matter is probably all that is need- \ned, and beyond this quantity the soluble matters must be more nutritive in \nproportion as they contain more albumen, ^ugar, and mucilage, and less nutri- \ntive in proportion as they contain other substances. \n\nIn comparing the composition of the soluble products afforded by different \ncrops from the same grass, I found, in all the trials I made, the largest quanti- \nty of truly nutritive matter, in the crop cut when the seed was ripe, and least \nbitter extract and saline matter ; most extract and saline matter in the autumn- \nal crop ; and most saccharine matter, in proportion to the other ingredients, in \nthe crop cut at tlie time of flowering. I shall give one instance : \n\n100 parts of the soluble matter obtained from the Dactylis glomerata, cut in \nSower, afforded. \n\nOf sugar . . . - - 18 parts \nOf mucilage - ... 67 \n\n\n\nAPPENDIX. \n\n\n\n29T \n\n\n\nOf coloured extract, and saline matters, \nwith some matter rendered insoluble \nby evaporation - - . 15 \n\n100 parts of the soluble matter from the seed crop, afforded, \n\nSugar ..... 9 parts \n\nMucilage ..... 8.5 \nExtract, insoluble, and saline matter 6 \n\n100 parts of soluble matter from the after math crop, give, \n\nOf sugar . . - . . 11 parts \n\nOf mucilage - - - - 59 \nOf extract, insoluble, and saline mat- \nters. 30 \n\nThe greater proportion of leaves in the spring, and particularly in the late \nautumnal crop, accounts for the difference in the quantity of extract ; and thp \ninferiority of the comparative quantity of sugar in the summer crop, probably \ndepends upon the agency of light, which tends always in plants to convert sac^ \ncharine matter into mucilage or^ starch. \n\nAmongst the soluble matters afforded by the different grasses, that of the \nElymus arenarius was remarkable for the quantity of saccharine matter it con- \ntained, amounting to more than one-third of its weight. The soluble matters \n.\'S\'om the different species of Festuca, in general afforded more bitter extractive \nmatter than those from the different species of Poa. The nutritive matter from \ntlie seed crop of the Poa compressa was almost pure mucilage The soluble \nmatter of the seed crop of Phleum pratense, or meadow cat\'s tail, afforded \nmore sugar than any of the Poa or Festuca species. \n\nThe. soluble parts of the seed crop of the Holcus mollis and Holcus lanatus, \ncontained no bitter extract, and consisted entirely of mucilage and sugar. \nThose of the Holcus odoratus afforded bitter extract, and a peculiar substance \nhaving an acrid taste, more soluble in alcohol than in water. All the soluble \nextracts of those grasses that are most liked by cattle, have either a saline or \nsubacid taste ; that of the Holcus lanatus is similar in taste to gum arabic. Pro- \nbably the Holcus lanatus, which is so common a grass in meadows, iittght bft \nmadt palatable to cattle by being sprinkled over with salt. \n\nI have found no differences in the nutritive produce of the crops of the dif- \nferent grasses cut at the same season, which would render it possible to esta. \nblish a scale of their nutritive powers ; but probably the soluble matters of the \nafter-math crop are alway,s from one-sixth to one-third less nutritive than those \nfrom the flower or seed crop. In the after math the extractive and saline mat- \nters are certainly usually in excess ; but the after-math hay mixed with sum-- \nmer hay, particularly that in which the fox-tail and soft grasses are a^iundant, \nwould produce an excellent food. \\ \n\nOf the clovers, the soluble matter from the Dutch clover contains mbst muci- \nlage, and most matter analogous to albumen : all the clovers contain more bittei- \nextract and saline matter than the common proper grasses. When ptiit-e clover \nis to be mixed as fodder, it should be >.vith siimmc" hav, rath\'^rthan alter-nrafh \n\n\n\n51? \n\n\n\nait ID ]s So \n\n\n\n\xe2\x80\xa2 \n\nPage. \n\nAcids, account of those found in vegetables 76 \n\nAge of trees, by what limited --.-.-- 17^ \n\nAlcohol, theory of its formation ........ 94 \n\nAlburnum, uses of - - - 46, 173 \n\nAlkalies, method of ascertaining their presence in plants - - 79 \n\neffects produced by, in vegetation ..... 20 \n\nAnimal substances, their composition, &c 188 \n\n\xe2\x96\xa0 ________^ decomposition of -...,. 187 \n\nAtmosphere, nature and constitution of - - - - - . I43 \n\nAnimal matter, mode of ascertaining its existence in soils - . 118 \n\nBark, its oiRce and uses 44j 166 \n\nBarks, their relative value for tanning skin ..... 65 \n\nBlight in Corn, its cause 181 \n\nBread, its manufacture, theory of its production - - . . 98 \n\nBurning, its use in improving soils - 233 \n\nCanker in trees, probable mode of curing - - . . . J80 \n\nCarbonic acid, a part of the atmosphere ...... 145 \n\nnecessary to vegetation ...... ^^2 \n\nCements, on those obtained from limestone 221 \n\nChemistry, its application to agriculture - 9 \n\n\' importance in agricultural pursuits - - . . gS \n\nCombustibles, simple, referred to- 36 \n\nCombustion, supporters of, mentioned 35 \n\nCourses of crops, particular ones recommended .... 242 \n\nCorn, its tillering, theory of this operation . - - - _ I6I \n\nDiseases of Plants, their causes discussed ..... igQ \n\nEarths, on those found in plants 81 \n\nElectricity, its influence on vegetation - - - . . . 33 \n\nElements chemical, of bodies 34 \n\n\xe2\x96\xa0 \xe2\x80\x94 \'\xe2\x96\xa0 \xe2\x80\x94 laws of their combinations .... 40 \n\nExcrements, use of as manures - 201 \n\nFairy rings, their causes - -. 243 \n\nFallowing, theory of 22, 239 \n\nFermentation, phaenomena of- 94 \n\nFly-turnip, plan for destroying or preventing 152 \n\nFlowers, their parts and office - 51 \n\nGeology, referred to as teaching the nature of rocks \xe2\x80\xa2 - - 134 \n\nCrafting, gencK^ views on this process - 173 \n\n\n\n800 INDEX. \n\nPag^ \nGrasses, on those iit tor pasture - - - - - - 244 \n\nGravitation, its effects on plants 27 \n\nGreen crops recommended - - - -- - - - 242 \n\nGypsum, its use as a manure 224 \n\nHeat, its effects on vegetables \' - - 32, 125 \n\nHusbandi-y diill, its advantages ....-,. 241 \n\nIce, its anti-pulrcscent powers ....... 190 \n\ntrrigation, theory of its effects 238 \n\nIrritability, vegetable, its existence doubted - - \xe2\x96\xa0 - - - 168 \n\nLand, causes of its fertility 139 \n\n\'\xe2\x96\xa0 ^ ban-eiincss --.-.... 141 \n\nLeaves, tiieir functions .--\xe2\x80\xa2-..... 45 \n\nLight, its effect on vegetation 153 \n\ntiimestone, its nature and uses ---.--. 20, 215 \n\n_ action in the soil - 21 \n\n\xe2\x96\xa0\' mode of burning 223 \n\n\xe2\x80\xa2\xe2\x80\x94 \xe2\x96\xa0 magnesian, its jjeculifer properties ... - 22, 219 \n\nLime, mode of ascertaining the quantity, in limestones and soils - 116 \nsalts of, on the mode of detecting them in soils ... 120 \n\nManures, on their applications --*..... 184 \n\nhow taken into the vegetable system .... 185 \n\nfei\'mentation of-------- 10, 205 \n\nin what state to be used \xe2\x80\xa2\xe2\x96\xa0 207 \n\nanimal .......... 201 \n\n~ mineral 218 \n\n\xe2\x96\xa0 > vegetable -.-.-.--.. 191 \n\nsaline 199, 213 \n\njSIalting, theory of the process of ---*--- - 149 \n\nMatter, powers of discussed --...--. 27 \n\nMetals, account of -... 37 \n\nMetallic oxides, those found in plants ..--.. 81 \n\nMildew, cause of -------.. . 181 \n\nMeat, method of preserving it ....... jgo ^ \n\nOils, fixed, their nature and production ...... 72 \n\nOxygene, its presence in the atmosphere, and uses . . \xc2\xab I47 \n\n. necessary to gerjniuation ..... 147^ igQ \n\nFaring and burning, theory of their operation - - - - . 234 \n\nPasture, where advantageous ........ 244 \n\nPlants, organization of 43, 98 \n\nPlants, parasitical, described as the cause of disease in corn - . 181 \n\nPeat mosses, on tlieir formation - 132 \n\non tiieir improvement ....._ 142 \n\nPutrefaction, methods of jjreventing ... . . . . 190 \n\nPith nature of ---.---.-. . 47 \n\nPlants, parts of - 43 \n\nQuicklime, injurious to soils ...._... 216 \n\nRocks, their number and arrangement ...... 134 \n\nthose from which soils are derived, or on which they rest - 137 \n\nSap, cause of its ascent discussed - -164 \n\ncourse of ^ 13, 162 \n\n-\xe2\x80\xa2"\xe2\x80\x94 - its composition discussed -- 104 \n\n\n\ni:nD\xc2\xa3:^\xc2\xbb \n\n\n\n301 \n\n\n\nPagft \n\n^alte, thtir uses as manure ^"9, 21S \n\n\xe2\x80\x94 \xe2\x80\x94 on such as are found in vegetables ... - - ol \n\non tliose found in soils, account of - - - \xe2\x80\xa2 \xe2\x96\xa0 " ^^^ \n\nSeeds, on those produced by crossing ^\' " \n\ngermination of 148 \n\ntheir nature and uses -\xc2\xbb ^-^ \n\nSimple substances desci\'ibed ..-.---- 36 \n\nSods, properties of -- ^"^f ^}\'f \n\ncomposition of .-.----- Hlj 1~^> \n\n\xe2\x80\x94 \xe2\x80\x94 method of analysing 11* \n\nformation of ------**"* I\'\' ^ \n\ntheir constituent parts 1^^ \n\nimprovement of -- 1^1 \n\n\xe2\x80\x94 \xe2\x80\x94 their classification ..------- lo-\' \n\nSubsoils, varieties of, and their effects ..---- 130 \n\nSoot, pi\'operties of as a manure .--.--- 209 \n\nSugar, mode of refining .-- - 59 \n\nTanning principle, its application to taiming 64 \n\n\xe2\x96\xa0 1 quantity in different baij^ ..... 65 \n\nartificial -\xe2\x80\xa2\xe2\x96\xa0 67 \n\nTemperature of soils discussed 125 \n\nTrees, habits of, discussed ...-.--. 178 \n\n\xe2\x96\xa0 M . cause of their decay _-.----. 173 \n\n. age of 174 \n\ntJrine, its use as a manure 200 \n\n\xe2\x96\xa0\\\'^egetables, their chemical composition S5 \n\n\xe2\x80\x94 \xe2\x80\x94 improvement of, by cultivation 176 \n\n\xe2\x80\xa2\' renovation of the atmosptiere ..... 158 \n\n. the causes of their growth discussed .... 171 \n\nVegetable matter, mode of ascertaining its quantity in soils - - 118 \n\n\xe2\x80\x94 \xe2\x80\x94 \xe2\x80\x94 its analysis -- 85 \n\n\xe2\x80\x94 \xe2\x80\x94 \xe2\x80\x94 \xe2\x80\x94 decomposition of, described - - - - 1 87 \n\n\xe2\x80\x94 principles, their arrangement in plants \xe2\x96\xa0 . - - - 98 \n\n\xe2\x80\xa2 life, phaenomena of discussed - . . . . - 171 \n\n- - matter, decomposition of -. 186 \n\nVegetation, influenced by gravitation 27 \n\ninfluence of light in 161 \n\nprogress of 152, 227 \n\nits effect on a soil 242 \n\nVeins or mines, their situations 136 \n\nWater, absorption of by soils -- 127 \n\nits state in the atmosphere 143 \n\nWheat, transplantation of .....-<.- 16j. \n\ncrossing of--------e- 177 \n\nWines, theory of their formation 93 \n\n\xe2\x96\xa0 \xe2\x96\xa0 quantity of spirits they contain -.-... 5g \n\n\n\nIXIiEX TO TKE APP\xc2\xa5iKl>lX- \n\n\n\nPag-e \n\n^^I\'rosiis canina, brown bent ----\xc2\xbb--- 289 \n\ncanina var. vmtica, awnless brown bent - - - - 289 \n\n\xe2\x96\xa0 fascicularis, tufted-leaved bent .-.--- 290 \n\xe2\x80\x94 \xe2\x80\x94 \xe2\x80\x94 lobata, lobed bent grass ---_-.-- 291 \n\xe2\x80\x94 \xe2\x80\x94 ^\xe2\x80\x94 mexicana, mexican bent grass - - - - \' - - 292 \n\xe2\x80\x94 \xe2\x80\x94 nivea, snowy bent gi\'ass .-.-_-. 289 \n\n\' palustris, March bent grass ------ 288 \n\nrepens, creeping rooted bent ____-- 291 \n\n\xe2\x96\xa0 stricta, upriglit bent grass -.--.-. 290 \n\xe2\x80\x94 \xe2\x80\x94 \xe2\x80\x94 stolonifera, fiorin creeping bent ------ 288 \n\n\xe2\x96\xa0 stolonifera var. angustifolia, creeping bent narrow leaves - 289 \n\n" vulgaris, fine bent grass --__.-- 287 \n\nAira aguatica, water hair grass .-_---- 281 \n\ncxspitosa, turfy hair grass --___-- 282 \n\njlexuosa, waved mountain hair grass - - - - - 37*4 \n\nAlopeciirus agrostis, slender fox-tail grass _ - - - - 292 \n\nalpint^, alpine fox-tail grass ------ 26O \n\npratensis, meadow fox-tail grass ----- 259 \n\nAnthoxaiithum odoratum, sweet scented vernal grass _ - _ 258 \n\nArundo colorata, striped-leaved reed grass - - - - - 278 \n\nAvena elatior, tall oat grass ----____ 269 \n\n- flavescens, yellow oat grass ------- 283 \n\npratensis, meadow oat grass --__--_ 273 \n\npubescens, dc^wny oat grass .-_---- 26O \n\nBriza media, quaking grass ----\xc2\xbb-__ 266 \n\nBromus aspei^ .--.--_--_ 299 \n\n\' cristatus ---------- 282 \n\ndiundrus - - -.- - . - - - _ 268 \n\nerecuis, upright perennial brome grass . - - - 270 \n\ninerniis, awnless brome grass ------ 287 \n\nlittoreiis, sea-side brome grass ------ 275 \n\nmuhiflonis, many-flowering brome grass - - - - 273 \n\n\xe2\x96\xa0 \xe2\x96\xa0 \xe2\x80\xa2- tectorum, nodding pannicled brome grass - - - - 267 \n\nsterilis, barren brome grass -..--_ 283 \n\nBunias orientaUs - - --.--___ <^\'7Q \n\nCynosurus cieruleus, blue moor grass ---,-__ 259 \n\ncristatus, crested dog\'s-tail grass . . - . _ 272 \n\nenicaformis, linear spiked dog\'s-tail grass - - - 285 \n\nDactylis cymsuroides, American cock\'s-foot grass ... - 293 \nglomerata, round-headed cock\'s-foot grass - - . - 266 \n\nElymus armnrixis, upright sea lyme grass ----- 28G \n\ngeniculatus, pendulous sea lyme grass .... 286 \n\n\xe2\x80\x94\xe2\x80\x94 \xe2\x80\x94 sibericds, Siberian lyme grass "^ \xe2\x96\xa0\xe2\x80\xa2 - . - 389 \n\n\n\n304 INDEX. \n\nifage \n\nFestuca cahvnaria, reed-like fescue grass -\xe2\x80\xa2-... 275 \n\ncamhrica ....--...-^ 267 \n\n(.uriuscula, hard fescue grass .---.. 269 \n\ndumetonim, pubescent fescue grass ..... 278 \n\nelatior, tUll fescue grass - - 276 \n\nfliiitans, floating fescue grass ...... 277 \n\nglabra, smooth fescue grass ...... 264 \n\nglmica, glaucous fescue grass - 263 \n\nhordiformis, barley-like fescue grass ..... 262 \n\n\xe2\x80\x94 \xe2\x80\x94 \xe2\x80\x94 loUacea, spiked fescue grass ...... 273 \n\ninyurus, wall fescue grass - - - - - - \' - 274 \n\n"^\xe2\x80\x94 \xe2\x80\x94 ovina, sheep\'s fescue grass - - - ... . - 265 \n\npemiata, spiked fescue grass ...-,.. 290 \n\npratensis, meadow fescue grass - - - - > . 271 \n\n\xe2\x80\x94 \xe2\x80\x94 \xe2\x80\x94 rjibra, purple fescue grass - 265 \n\nHedysarwn onobri/chis, sainfoin - - . - - .- . 280 \n\nHordeuin bidbnsum, bulbous barley grass -.--.. 275 \n\n\xe2\x80\x94 \xe2\x80\x94 \xe2\x80\x94 murinum, wall barley grass - , - - - - . - 282 \n\n\xe2\x96\xa0 pratense, meadow barley grass . - . ... 281 \n\nHolcus lanatns, meadow soft grass ....... 277 \n\n\xe2\x80\xa2 \xe2\x96\xa0\xe2\x96\xa0 mollis, creeping soft grass . - - . - . . 283 \n\nodoratns, sweet scented soft grass ...... 258 \n\nLolium peremie, perennial rye grass ....... 271 \n\nJifedicago sativa, lucerne - .. . . . . . . 5S0 \n\nJ^elica aerulea, purple malic grass -...-.. 293 \n\nJyfiliu7n effusuvi, common millet grass ...... 270 \n\nJVarJjw striata, upright mat grass --..-.. 27r \n\nJPanicum dactylum, creeping panic grass ...... 288 \n\n\' \xe2\x96\xa0 \xe2\x96\xa0- sangidnale, blood coloured panic grass - -\xe2\x80\xa2 . . 291 \n\nviride, green panic grass -_..... 291 \n\nPhalaris canaviensis, common canai\'y grass ..... 293 \nPhlenm nodosum, bvilbous- stalked cat\'s- tail g^-ass .... 285 \npratense, meadow cat\'s-tail grass ...... 285 \n\n\xe2\x80\xa2 var. miliar, meadow cat\'s-tail grass, van smaller - 285 \n\nPoa alpina, alpine lueadow grass ....... 260 \n\n(ingusiifolia, narrow-meadow grass - - - \xe2\x80\xa2 . - - 268 \n\naquatica, reed meadow grass - 281 \n\nctendea, v. p. pratense, short bluish meadow grass ... 262 \n\ncnmpressa, flat-stalked meadow grass 281 \n\ncristnta, crested meadow grass ....... 274 \n\nelatior, tall meadow grass ........ 269 \n\nfertihs, fertile meadow grass ....... 278 \n\n\xe2\x80\xa2 var. b. fertile meadow gn^ss, var. 1. .... 284 \n\nmarifima, sea meadow grass ....... 272 \n\n/)!\'ato;47,9, smooth-stalked meadow grass ..... 261 \n\n\xe2\x99\xa6 ?riTva/j,s, roughish meadow grass . . - . - . 262 \n\nPotirinm sauguisorba, burnet ........ 279 \n\nSlipn pennata, long armed feather grass ...... 29i \n\nTrIfoHum r.ncrorhiznm, long-rooted clover ..... 279 \n\npratense, broad-leaved cultivated clover .... 278 \n\nrepens, white clover --...... 279 \n\nTritiaim repens, creeping rooted wheat grass 29^ \n\n^^ sp. wheat ^yvass - 277 \n\n\n\nTUlEiATl^\xc2\xa5i \n\n\n\nON \n\n\n\nAS \n\nFOUNDED ON ACTUAL EXPERIENCE:, \n\nAND \n\nAS COMBINED WITH THE LEADING PRINCIPLES \n\nOB \nIN WHICH THt \n\nTHEORY AND DOCTRINES OF SIR HUMPHRY DAVY, \n\nAND OTHER AGRICULTXJEAL CHEMISTS, \n\nAKE RENDERED FAMILIAR TO THE EXPERIENCED lARMER- \n\n\n\nBY A PRACTICAL AGRICULTURIST. \n\n\n\nPHILADELPHIA: \n\nI\'UBIISUED BY B. WARNEIl, 171, HIKH STKA\'KJ . \n\n\n\n182^^1 \n\n\n\nIPIBISI^ii\'lPISc \n\n\n\nIflEORY would always coincide with practice, if \nthe speculator could hold to the mind\'s eye a complete \nmodel of the subject discussed ; could see all the parts \nin action together, as a machine is surveyed ; and mea\xc2\xbb \nsure excitements and obstructions precisely as they ope- \nrate. But, in treating of arts which depend for their \nsuccess on natural operations, the most difficult part of \nthe task is, to assign the proper degree of influence to \nthe many causes and qualities which act invisibly, and \ncannot be controlled by man. Hence, the philosopher \nwho exercises the strongest intellect on previous systems \nof Jigriculture, and on the knowledge accumulating \nfrom the progress of practical experience and scientific \ndiscovery^ cannot be certain that some latent interme- \ndiate impulse in tl\\e machine of vegetation, has not elu- \nded bis anxious inquiry, or that he is aware of all the \ncauses which exist, and of their conducing to a general \neffect. \n\nAmidst these difficulties, the Theorist cannot advance \nany considerable way beyond the track of experience^ \nin the pursuit of materials for a new system, without be- \ning liable to move on a line which subsequent experience \nmay be compelled to abandon- Meanwhile, an in- \ndependent and equally specious hypothesis may uphold \nthe reasonableness \'of some branch of established prac- \ntice impeached by the new system, and vindicate from \n\n\n\nIV I\'UEFACE. \n\nthe name of prejudice that slow and circumspect transi- \ntion from tried courses to alleged improvements, which \nprevents a whole country from being involved in the \nspeculations and risks of an experimental farm. \n\nThe views of Sir Humphry Davy in regard to Soils \nand Manures may, on many fundamental points, be re- \nceived without dispute, as no less sound and practical \nthan they are original and ingenious : but he has advan- \nced some new doctrines, and become the advocate of \nsome recent partial practices, which do not accord with \nthe general experience of Gardeners and Agriculturists. \nNevertheless, by the connection with the subtile princi- \nples and problems of Chemistry under which these are \ngiven, the Practical Farmer who may feel dissatisfied \nwith a particular part of the professor\'s theory, because \nit is at variance with his own maxims derived from ex- \nperience, is perplexed and silenced by the reasoning, \nbeing unable to enter with perspicuity into the grounds \nof argument drawn from the depths of philosophy : \nthus he is asliamed to question a train of deductions by \n"which he is conducted to a doctrine in which he does \nnot confide. But when theory is opposed to theory, \nthe practical man is disembarrassed, and raised to the \nsituation of an arbiter. \n\nIt may be added, that some few points among the \ndifliiculties of Chemistry, treated by Sir Humphry Davy \nas fundamental principles, are not yet considered as es- \ntablished by all the great Chemists; consequently, the \nspeculative deductions from these must stand over for \napproval, until the assumed principle be exploded or \nconfirmed. \n\n\n\nPREFACE. V \n\nIn the following Treatise, the leading doctrines of \nthis illustrious Contributor to the formation of an en- \nlightened system of Agriculture are brought under re- \nview; in order that such as are obviously well founded^ \nor tenable against superficial objections, may be recom- \nmended to general practice ; as well by corroborating \nfacts and observations, as by the connected order and \nsimplified form in which they are presented ; \xe2\x80\x94 and that \nsuch as are open to considerable objection, either on prac- \ntical grounds, or by collision with a contrary hypothe- \nsis, may be exhibited at the tribunal of reason, and sub- \njected to the test of experience, in so plain a shape as \nshall bring them within the grasp of the Practical Ag- \nriculturist who may have formed no previous acquaint- \nance with Chemical Science. \n\n\n\n^m^\xc2\xa7, \n\n\n\nPAOIi \n\nUse op the Sort -- 9 \n\nOn the Basis of Soils 10 \n\nTerms for Soils Defined ..-.---\xe2\x80\xa2 11 \nOn the Improvement of Soils : \n\nI. Jiy the Admixture of Earths, to improve the Texture of tlie Soil - 13 \n\nTeats of Sniln - 15 \n\nCoiTectiven of ill-conntiliitcd Soils .- \n\n1. Iron in its Acid Combinations ..... 22 \n\n2. Fixcess of pure Calcareous Matter - ... - 22 \n\n3. Excess of Carbonate of Lime .----- 23 \n\n4. Redundant Sand 23 \n\n5. Excess of Vegetable Matter ...--- 23 \n\n6. liedundancy of Clay -- 23 \n\nn. By Druininff ------.--- 23 \n\nIII. By Vanng and Bxirni\'ng ...... 24 \n\nIV. By Turmng-in Green Crops us Manure ... - - 25 \nV. By Fallo-wintf .....---. 26 \n\nVI. By Irrigation ......... 35 \n\nVII. By applying Earths as Manures : \n\n1. I.ime as a Solvent (Quick-lime) 42 \n\n2. Mild Lime - \xe2\x96\xa0 43 \n\nTime of laying on Lime .--\xe2\x80\xa2.. 46 \n\n3. Magnesia -- - 47 \n\n4. I\'liospliate of Lime 47 \n\n5. Gypsum ..-. 47 \n\n6. Burnt Clay 54 \n\nConsidered as the Food of Plants - - - . 38, 39 \n\nVIII. By introducing Mineral or Saline Substancest as Manures : \n\n1. Common Salt --.------ 57 \n\n2. Comparative Elfect of different Salts .... 57 \n\nIX. By Manuring -with Refusp. Substances not excrementitiom : \n\n1. Street and RoaflDirt, and the Sweepings of Houses - 58 \n\n2. Soot 58 \n\n3. fJoal ashes 58 \n\n4. Coal-water -...----- 59 \n\n5. Wood-ashes 59 \n\n6. Carbonate of Ammonia - 59 \n\n7. Coal-tar - - - 59 \n\n8. Rones 59 \n\n9. Horn 59 \n\n10. Hair, Feathers, and Woollen Rags 59 \n\n11. Refuse of Skin and Leather ..-.-. 60 \n\n12. Bleacher\'8 Waste .--.-\xe2\x96\xa0- 60 \n\n\n\nVm CONTENTS, \n\nPagb \n\n13. Soaper\'s Waste, 60 \n\n14. Fluids of dissolved Animal Substances - - . - 60 \n\nRlood 60 \n\nSugar-baker\'s Scum 60 \n\nGraves 61 \n\nOily Substances \xe2\x80\x94 Train Oil and Blubber ... 61 \n\nOil-cake 62 \n\n15. Refuse Fish 62 \n\n16 Carrion -- - -\xe2\x80\xa2- - - - . . 62 \n\n17. Rape-seed Cake 63 \n\n18. Malt Dust 63 \n\n19. Sea weed 63 \n\n20. Dry Straw, and Spoiled Hay .-...- 63 \n\n21. Vegetable Mould -.--.-.- 64 \n\xe2\x80\xa222. Woody Fibre : ........ 64 \n\nTanner\'s Spent Bark ....... 6^1 \n\nInert Peaty Matter - 64 \n\nShavings of Wood and Saw.dust 65 \n\nThe Fibre and Grain of Wood ..... 65 \n\n23, Ashes of Vegetables not Woody ..... 65 \n\nBurnt Straw 65 \n\nPeat-ashes 65 \n\nX. By Excremcntitiorts Substances applied as J\\Ianure : \n\n1. Dung of Sea-birds 66 \n\n2. Night-soil 66 \n\n3. Pigeon\'s Dung ........ 67 \n\n4. Tlie Dung of Domestic Fowls ..... 67 \n\n5. Rabbit\'s-Dung 68 \n\n6. The Dimg of Cattle 68 \n\n7. Hog-dung 70 \n\n8. Urine 70 \n\nJManagement of J\\Iamire From the Homestead : \n\nProfessor DaA7\'s Theory of Composite Manure - - . 71 \n\nObjection noticed by the Professor . - . . . 72 \n\nHis own Practical Application of the above Theory \xe2\x80\xa2 - 72 \n\nFree Remarks on the Theory, and on its Practical Application 72 \n\nRecapitulation 83 \n\nAdditional Notes, gee. -.--\xe2\x80\xa2\xe2\x80\xa2- , 85 \n\n\n\nTREATISE \n\n\n\nON \n\n\n\n^Olli^ AXU MAX^IVE^. \n\n\n\nUSE OF THE SOIL. \n\nOORRECT views of the office of the soil disclose the ration- \nale of approved modes of tillage ; if one mode is found supe- \nrior to another, they lay open the cause of it ; and proceeding \nfrom courses which are experienced to l)e beneficial, a principle \nis thus obtained for extending their application. \n\nOne great use of the soil, is to afford a bed for the plant, \nand a cover for its roots from the sun and from the wind ; while \nthe roots, by taking hold of the ground, act as stays and supports \nfor the trunk of the plant. A second important office is that \nboth of a depository and a channel of nutriment : In these rela- \ntions, the soil ought to contain a certain proportion of common \nvegetable basis, and of peculiar substances found in plants on \nanalysis ; it ought again to be easily permeable to air ; also po- \nrous, for the percolation of water and passage of fluid manures ; \nwell fitted for allowing a plant| by the fine tubes within its-roots, \nto derive sustenance slowly and gradually from the dissolved \nand soluble substances mixed with the earths. \n\nAs the systems of roots, branches, and leaves, are very dif- \nferent in different vegetables, so specific plants have a preference \nfor peculiar soils in which they flourish most. The plants that \nhave bulbous roots require a looser and lighter soil than such as \nhave fibrous roots : and those of the latter, which have short \nand slender fibrous radicles, demand a firmei soil than such as \nhave tap roots or extensive lateral roots. Hence, when succes- \nsive crops of the same plant have drawn out from a soil the pe- \nculiar properties most adapted to its individual nature, the bed \nof earth becomes less fit for the same plant, until it has been \nrested and recruited : while it may be fitter for some other plant \nof a different constitution than it originally was ; though ex- \nhausted in regard to the crop which it has long l)orne, it may be \nfresh for a new sort of vegetable. In short, the principles laid \ndown in the " Practical Gardener," (Introduction to the Knv \nCHEN Garden, under the head Rotation of Crops^ are more or \nfess applicable to all the branches of Gardening and Agriculture. \n\nB \n\n\n\n10 \n\n\n\nBASIS 01\' SOILS. \n\n\n\nSir Humphrey Davy, an illustrious ornamant of the English \nschool of Chiiinistry, is not more distinguished by his discoveries \nin philosophy, than by seeking, with true ambition, to make pro- \nfound knowledge subservient to the common arts by which the \ncommon wants of mankind are supplied ; he has contributed \nlargely to the service of agriculture, by publishing his scientific \nresearches into the composition of earths, and the true food of \nplants. With the object of founding a course of agricultural \nimprovement on fixed principles, he has communicated, in the \nElements of Agricultural Chemistry/\'^ some very important re- \nsults from a systematic train of experiments. We propose to \nlay before the Reader the substance of his leading conclusions, \ndivested, as much as possible, of chemical terms ; and to re- \nview the peculiarities of his system with candour and indepen- \ndence ; concentrating, for unity of method, scattered articles \nbelonging to the same branch of rural economy. \n\nIn the extensive field of his inquiry, he touches on the prin- \nciples of many other arts ; it therefore becomes necessary, in \nsketching an outline after him, which shall embrace only the \ndepartment of agriculture, to connect the extracts by details and \nobservations for which Sir H. Davy is not responsible. \n\n" Soils, in all cases, consist of, either a mixture of finely di- \nvided earthy matter,| \xe2\x80\x94 or of earthy matters not reduced to pow- \nder, such as gravel and other stones ; more or less combined \nwith decomposed animal or vegetable substances; saline ingre- \ndients, also, frequently lodge in a soil ; and the earthy matters \nare frequently accompanied with the oxides of minerals, parti- \ncularly the oxide of iron.:!: The earthy matters form the true \nbasis of the soil ; the other parts, whether naturally present, or \nartificially introduced, operate in the same manner as manures. \n\nFour Earths generally abound in soils :<^ 1. The. aluminous^ \nj. e- Clay, including alum ; 2. The siliceous^ i. e, Flint, in va- \nrious stages of decomposition, including flinty sand; 3. The \ncalcareous^ i. e. Limestone, under various modifications,including \nmarie, chalk, and chalky sand ; 4. The magnesian^ i. e. Magne- \nsia, a stone sometimes mistaken for commonlimestone, but when \nburnt and applied to land it is much longer in passing from \na caustic to a mild state, and under most circumstances is \nhighly pernicious to vegetation. \'llie small proportion in \n\n\xe2\x80\xa2 This work, which will be frequently referred to. Is entitled, Elanents of \n^gricnltiiral Cliemistry, in a Cowsf of Lfcturcs for the Board of ^igricultitre. \nBy Sir Humphry Davy, LL.D. F.H.S. &c. &.c. 8vo. American, 1820. \n\nt Ibid. p. 15. , \n\nt Ibid. pp. Ill, 123. \n\n\xc2\xa7 Ibid. p. 15. \n\n\n\nTERMS FOR SOILS. 11 \n\nwhich it may be sometimes bentficial, will be afterwards ex- \nplained. \n\nThe above are the only earths which have been hitherto found \nin plants. \n\nOther primitive earths sometimes enter into soils by the pul- \nverization of rocky materials. \n\n\n\nTERMS FOR SOILS DEFINED. \n\nThe popular terms for soils are seldom applied with precision. \nWhat one man c;(lls a marie, another will call a clay ; and so on. \nBut if a general circulation and acceptance could be obtamed \nfor the principles of definition judiciously laid down by Profes- \nsor Davy \xe2\x80\x94 according to which a soil is to be styled a clay, sand,, \nor chalk ; a marie, loam or peat ; or a compound of these \xe2\x80\x94 the \ncharacteristic terms would be every where intelligible. \n\nIn framing a system of definitions, a soil is to take a particular \ndenominationfrom a particular kind of earth, not exactly in pro- \nportion as that earth may preponderate, or not, over others in form- \ning the basis of the soil, but rather in proportion to the influence \nwhich a particular kind of earth, forming part of the staple, has \non tillage and vegetation. Thus, as clay is a substance of which \na comparative small quantity will give a cold and stubborn cha- \nracter to a soil, the name claifey is often properly bestowed, \nwhere the quantity of pure clay to be collected from a given \npiece of land, is but as 8 to 42, compared with the quantity of \nsand which another field may contain, and yet barely deserve \nthe denomination of sajidi). \n\n"The term clayey should not be given to a soil which con- \ntains less than one-sixth of aluminous matter ;" because less \nthan that will not be attended with the common effects which \ngovern the culture, and limit the crops, for a clayey sod. \n\nThe epithet sandy is not an appropriate distinction for any \nsoil that does not contain at least seven-eight parts of sand ; and \nsandy soils are to be distinguished into .siliceous sandy or flinty \nsand, and calcareous sandy or chalky sand. \n\nThe word calcareous, or any denomination implying the \npresence of mild lime or chalk, is not properly applied unless a \nspecimen of the soil is found stronglv to effervesce with acids, \nor unless water having a channel in the soil affords a white \nearthy deposit when boiled. \n\nA marle consists of mild lime with a small proportion of \nclay, and sometimes of peat, with a mixture of marine sand \nand animal remains ; the lime having originated, for the m.ost \npart, from the decomposition of sea-shells. \n\nA soil maybe treated as maonesian, where but a small \n\n\n\n12 . IMPROVEMENT OF SOILS. \n\ncomparative quantity of magnesian stone is present ; as will be \nexplained in treating of Magnesia as a manure. \n\nHie combination of animal or vegetable matter in an inferior \nproportion with earthy matter, but not lower than one-sixth, \nmakes a loam : the word loam should be limited to soils con- \ntaining at least one-third of impalpable earthy matter (distin- \nguishable by the touch from sand, chalk, or clay,) combined \nwith decayed animal or vegetable substances not exceeding half \nthe weight of the mere earth; the earthy matters may compre- , \nhend aluminous, siliceous, or calcareous ingredients, and in \nsome cases be mixed with mineral oxides: according to the pro- \nportions of which, the soil may be red loam, brown loam, ot \nblack loam ; and in regard to the basis, a clayey loam, a sandy, \nor a chalky loam. \n\nA superior proportion of vegetable matter, that is to say, an \nexcess of this above half the bulk of the earthy basis, makes a \nPEAT. To bring this kind of soil into successful cultivation, \nthe quantity of vegetable matter must, in most cases, either be \nreduced or counterbalanced by the admixture of some of the \nsimple earths. \n\nWhere a slight tincture of any particular mineral substance \nhas a strong effect on vegetation, this quality should be indica- \nted by a corresponding word prefixed to the principal name for \nthe soil. Thus the presence of either salts of iron, or sulphate \nof iron, ought to be marked by prefixing the term ferruginous \nto the denomination taken from the basis, to remind the culti- \nvator that the effect on vegetation will be pernicious, unless he \nhas recourse to an effective remedy. If on the contrary, oxide \nof iron be found in the soil, there is seldom any occasion to no- \ntice it in the name: in small quantities, it forms a useful part \nof soils, and has been found to constitute from a 15th to a 10th \npart of several highly fertile fields : it is found in the ashes of \nplants. To persons unacquainted with chemistry it may be use- \nful to add, that salt of iron exhibits the crystals obtained from \niron by the action of an acid fluid. Sulphate of iron is Cop- \nperas, a native kind of which is produced in some soils by the \neffect of the springs and earths on each other. Black oxide of \niron is the substance that flies off from red-hot iron when ,it is \nhammered. Iron appears to be only hurtful to vegetation in \nIts acid combinations. See Tests of Soils. \n\n\n\nIMPROVEMENT OF SOILS. \n\n\n\nAlmost all the expedients \'for improving, enriching, or cor \nrecting a soil, known to agriculturists, may be comprehended \nunder one of the following heads : \n\n\n\nIMPROVEMENT OP SOILS. 13 \n\n1 . The admixture of Earths to improve the Texture of the \n\nSoil. \n\n2. Draining. \n\n3. Paring and burning. \n\n4. Turning in Green Crops as Manure. \n\n5. Fallowing. \n\n6. Irrigation. \n\n7. Applying Earths as Manures. \n\n8. Introducing Mineral or Saline Elements as Manures. \n\n9. Manuring with Refuse Substances not excrementitious; \n10. Manuring with Excrementitious Substances. \n\nI. By the Admixture of Earths^ to improve the Texture of the \n\nSoil. \n\nThis is a distinct thing from applying Earths as a manure. \nIt is of avail in proportion as the smallness of the tract, or the \nvalue of the plant, to be cultivated, allows the free introduction \nof new earths, until the staple of the land is composed as desired. \nAlmost all sterile soils are capable of being thus improved ; and \nsometimes the latent pernicious quality which destroys the va- \nlue of an extensive tract of land, can be corrected without much \nexpense. \n\nThe best constitution of a soil, is that in which the earthy \nmaterials are properly balanced, so as to combine as many ad- \nvantages of different ingredients as are compatable, and so as \nto obviate the defects attending any single kind of earth. \n\nThe ground, or basis of the soil, should be well adapted for \nthe admission of air, and for the percolation of moisture, with- \nout retaining it in winter. \n\nA well-tempered aptness in the soil to absorb water frofn air, \nand to retain it in a latent form, is clearly connected with fer- \ntility. The power to absorb water by attraction, and to hold \nmoisture without being wet, depends on the mechanical struc- \nture of the particles of earth, and the balancing effect of diffe- \nrent earth. Thus sand will attract moisture, but will not keep \nit lonjr under the influence of heat. Clay will long retain wa- \nter which has fallen upon it, and always keep moist under a hu- \nmid atmosphere : but in continued dry weather, with summer \nheats, the surface of it, being baked into an almost impenetrable \ncrust, is little capable of absorbing moisture. Hence crude \nclays form equally bad lands in extremely wet or extremely dry \nseasons. Chalk is of a middle nature, in this respect. It re- \nsults, that the soils best adapted for supplying the plant witli \nmoisture by atmospheric exhaustion are compositions*\' of ?an(l \n\n* Elements of AgricuUurul (\'hemistry, p. 141. \n\n\n\n14 IMPROVEMENT OF SOILS. \n\nfmel}^ divided clay, and pulverized chalk, with a proportion of \nanimal or vegetable matter.* \n\nThere is besides, in particular earths, an agency subservient \nto vegetation, which depends on chemical affinities, in those \nearths, for elementary substances floating in the air, or de]}osited \nin the soil. Thus, both pure clay and carbonate of lime have \nan attraction for volatile oils and solutions of oil and sapona- \nceous matters, and for much of the pulpy stuff fust disengaged \nfrom organic remains. Hence a limited pifoportion of these \nearths contributes to form a rich and generoufi soil ; because they \nlong preserve in their pores the prepared nourishment of vege- \ntables, parting with it gradually as it is drawn by growing plants,- \nand refusing it to the fainter action of air or water. \n\nThe properties of a soil may be aggravated or tempered by \nthe nature of the Subsoil. When the upper layer rests upon \na bed of stone, or of flinty gravel, it is much sooner rendered \ndry by evaporation ; an efl^ect which is beneficial, or otherwise, \nas the climate is moist in excess, or inclined to aridity. A clayey \nfoundation counteracts the readiness of flinty sand to part with \nmoisture to a drier climate ; so does a bed of chalk in a less \ndegree. \n\nA soil is neither fit for tillage nor pasture, if it consist en- \ntirely of impalpable matters,! or of pure clay, pure silica, or \npure chalk. Sand may abound in a higher proportion than the \nmore tenaceous earths, without causing absolute barrenness. \nThus a tolerable crop of turnips has lieen raised on a soil of \nwhich eleven parts in twelve were sand. A good turnip soil \nfrom Holkham was found to contain f parts of siliceous sand. \nIf the quantity of impalpable earth and finely divided organic \nmatter l)e a little increased beyond what a sand plant requires, \nit will suffice for good returns of barley. Although wheat de- \npends more on a rich staple, happilj\' the constituents of land fit \nfor it are combined with very great diversity. An excellent \nwheat soil, from Middlesex, afforded ^ of sand ; the rest was \nchalk, silica, and clay, pretty equally distributed, with a propor- \ntion of organic matter so surprisingly small (only 22 parts in \n500) that it may be apprehended some considerable substance, \nconvertible into food for a growing plant, might be included in \nthe chalk. Chalk may in the next degree form the prepondera- \nting earth of good soil. A large portion of England is chalk ; \n\n* The compound of carlli, which seems every where most fiivonrable to \nve.G^etation, is that which consists of one-third of chalk, half of sand, and a \nfifth of clay : from a Paper on the Chemical .^Inali/fiis of Soils, translated from \nthe Italian of Tahbroni, hy Arthur Young-, lisq. (^Jhinals of .^s\'l\'icullitir, vol. \nviii. 173.)\xe2\x80\x94 " A fifth of clay :" this proportion is too larj^e ; independent of \nconsumable or cropping manure ; by which the clay should be reduced to one- \nsixth or lower. \n\n\xe2\x80\xa2J Elements of Agricultural Chemistry, p. Ij."!, \n\n\n\nTESTS OF SOILS. i5 \n\nand many of the districts where it is the staiile earth, liberally \nrepiiy cultivation.*" \n\nThe Warp-land ^^ alluvial soil) in the East Riding of York- \nshire, is a strong clayey loam, the fertility of which can hardly \nbe equalled. The sediment gradually adding to the depth of \nthis warp-land, being brought from the higher country by the \nnumerous rivers and streams which open into this common es- \ntuary, is composed of a variety of substances. Decomposed \nvegetable and animal matter should be from one-ei^g-hth to a \nfourth of the bulk of the earthy substances, according to the \ndependence of the expected crop on the nutritive power of the \nsoil. \n\nMany soils (observes Sir H. Davy) are in popular language \ndistinguished as cold ; and the distinction, though at first view \nit may appear to be founded on prejudice, is as just on philoso- \nphical principles as it is consonant to the experience of the \nfarmer. Some soils are constituted for imbibing a much \ngreater degree of heat from the rays of the sun ; and of soils, \nbrought to the same degree of heat, some cool much faster \nthan others. Soils that consist chiefly of a Stipf white clay, \ntake heat slowly ; and being usually very moist, they retain \ntheir heat only for a short time. Chalks are similar in be- \ning slowly heated : but being drier, they retain heat longer. \nA Black soil containing much soft vegetable matter, \nif the site and aspect dispose it to dryness, is most heated \nby the sun and air : all the coloured soils, especially those \ncontaining much carbonaceous matter (charcoal,) or ferru- \nginous matter (iron,) are disposed for acquiring a much higher \ntemperature than pale-coloured soils. When soils are per- \nfectly dry, those that most readily become heated by the solar \nrays, likewise cool most rapidly. Moisture without fermenta- \ntion retards the accession of heat, and accelerates its escape. \nThe faculty of absorbing and retaining moisture has been al- \nready brought under tiotice. The method of detecting the pre- \nsence of some ingredient in the soil which the eye cannot per- \nceive, and which escapes the touch when a portion of mould is \nrubl)ed between the fingers, is by having a specimen of the earth \nof such cubical dimensions as may be thought proper, dug out ; \nand finding the materials of it by various chemical tests. \n\n\n\nTESTS OF SOILS. \nFor the common purposes of agriculture, the natural consti- \n\n\xe2\x80\xa2 Mr. Stricklund states the remarkable fact, that the .c^reat vein of clialk tci\'- \nminates in the East Hiding; of Yorkshire ; and beyond it northward, no chalk \nis found ill the island. See also a Map Delineatm^ the Strata of Enjlund and \nWales, with part cf Scotland, by W. Sinitii, 1815. \n\n\n\n16 TESTS OP SOILS. \n\ntution of a virgin soil, or the state of improvement which \nland under tillage has acquired from artificial causes, can, in \nthe great majority of cases, be sufficiently determined by \ntaking up portions of earth in different parts of a field, regard- \ning the soil as a separate layer from the subsoil, or strata un- \ndisturbed by cultivation ; and examining these by the common \nlights which persons employed in agriculture have derived from \nexperience. But when the nature of a virgin soil is entirely \nunknown, no previous trials of its powers having been made ; or \nwhen a cultivated field unaccountably baffles the ordinary course \nof skilful husbandry, while lands constituted apparently like it \nmake good returns under similar treatment; it is proper to \nhave recourse to the aid which modern chemistry offers to \nagriculture, for a full and accurate knowledge of the grounds \non which success may be expected, or the causes of failure ex- \nplained and rectified. \n\nThe instruments required for the analysis of soils are few, \nand of small cost : \xe2\x80\x94 a pair of scales, large enough to weigh a \nquarter of a pound of common earth, and so delicately exact as \nto turn when loaded with a grain ; a set of weights, correspond- \ning with the same limits ; a wire sieve, just coarse enough to \npass mustard-seed ; a comuion kettle, or small boiler ; an Ar- \ngand lamp and stand ; two or three Wedgwood crucibles ; eva- \nporating basins ; a pestle and mortar ; a bone knife ; some fil- \nters, made of half a sheet of blotting-paper, folded so as to con- \ntain a pint of liquid, and greased at the edges. \n\nThe principal tests, or chemical re-agents for separating the \nconstituents of the soil, are : Muriatic acid (spirits of salts ;) \nsulphuric acid (oil of vitriol ;) pure volatile alkali, dissolved in \nwater ; solution of prussiate of potassa ; solution of potassa \n(soap ley ;) solution of neutral carbonate of potassa ; succinate \nof ammonia ; nitrate of ammonia ; solution of carbonate of am- \nmonia ; solution of muriate of ammonia. Dry carbonate of \npotassa is sometimes wanted in fusing earths. \n\nThe quantity of soil conveniently adapted for a perfect ana- \nlysis is from 200 to 400 grains. It should be collected in dry \nweather, and exposed to the atmosphere till it becomes dry to \nthe touch. \n\nIndependently of regular analysis, the specific gravity of a \nsoil assists to indicate the quantity of animal and vegetable mat- \nter it contains ; because the atoms of either are lighter than the \natoms of cla}\', of sand, or of lime. In proportion as a soil is \nlight, it maybe presumed to be rich. Before a soil is analysed, \nthe other physical properties of it should also be examined ; be- \ncause they denote, in a sensible degree, the sorts of earth in its \ncomposition, and serve to guide the order in which the chemi- \ncal tests are applied. Siliceous soils are generally rough to the \ntouch, and scratch glass, when rubbed upon it ; calcareous soils \n(besides effervescing with acids, a trial to be afterwards descri- \n\n\n\nTESTS OF SOILS. 17 \n\nbed,) when in the shape of sand, do not scratch glass ; and clay^ \nwhile it is generally distinguishable by the touch, neither \nscratches glass nor effervesces with acids ; ferruginous soils are, \nfor the most part, of a red or yellow colour, or rusty-brown. \n\n1. Measure of Absorbent Power by the Dissipation \nOF Latent Water. \xe2\x80\x94 After soils have been dried by continu- \ned exposure to the air, they still contain a considerable propor- \ntion of water which adheres to the earths, and to the animal and \nvegetable rudiments, in such obstinate combination, that it can \nonly be driven off by a high degree of heat. To free a spe- \ncimen of soil from as much of this water as may be, without \notherwise affecting its constitution, let it be heated for ten or \ntwelve minutes over an Argand\'s lamp, till its temperature at- \ntain 300\xc2\xb0 of Fahrenheit. If a thermometer t)e not used,* the \nproper maximum of heat may be measured by keeping a piece \nof wood in contact with the bottom of the dish : While the co- \nlour of the wood remains unaltered, the heat is not excessive : \nas soon as the wood begins to be charred, discontinue the pro- \ncess. If a higher heat were applied, the vegetable or animal \nmatter would be decomposed, and all the following train of ex- \nperiment be rendered illusory. \n\nThe loss of weight in the soil thus dried should be noted, as \nIndicating the absorbent power of the S(jil. Supposing the spe- \ncimen to have previously weighed 400 grains, the loss of fitty \n(or an eigth part) denotes a soil absorbent and retentive ot wa- \nter in the greatest degree : such a soil will generally be found to \ncontain either much vegetable or animal m.atter, or a large pro- \nportion of aluminous earth, in which two respects this indica- \ntion is equivocal ; but the tests to follow will decide. When the \nloss is onlv from a twentieth to a fortieth part of the whole, the \nsoil is but slightly, absorbent, and siliceous earth probably forms \nthe greatest part of it. \n\n2. Separation of Gross Fragments. \xe2\x80\x94 Loose stones, gra- \nvel, and vegetable fibres, are artfully kept in the specimen im- \ntil after the water is dissipated: for they participate, in different \ndegrees, in that power of alisorbing moisture which affects the \nfertility of land. After the process of heating, detach these ; \nby bruising the soil gently in a mortar, and passing it through \nthe sieve. Take separate minutes of the weights of the vegeta- \nble fragments, and of the gravel and stones ; distinguishing the \nnature of the latter. If calcareous, they will effervesce with \nacids ; if siliceous, the-y will scratch glass ; and if aluminous, \n\n.they will be easily cut with a knife, and will refuse the tests^of \nlime and flint. \n\n3. Separation of the Sand. \xe2\x80\x94 The greater numher of soils \n\'.ontain varying proportions of sand more or less granulated. It \n\n* FJem^nts of Agricultural Chemistry, p. 112. \nC \n\n\n\n18 TESTS OF SOILS. \n\nis necessary to separate the sand from the impalpable or more \nfinely divided matters; such as clay, loam, marie, vegetable and \nanimal atoms. Uo do this, boil the silted mass in four times its \nweight of water : when the texture of the soil is broken, and the \nwater cooled, alternately shake the sediment in the vessel, and \nsuffer it to settle ; for in subsiding, the different parts will be \ndistributed in layers. Thus treated, the coarse sand will gene- \nrally separate in a minute, and the finer in two or three minutes, \nwhile the infinitely small earthy, animal, or vegetable matters, \nwill continue in state of mechanical suspension: so that by pour- \ning the water from the vessel after three minutes, the sand will \nbe found divided from the other substances. The other sub- \nstances, with the water containing them, must be deposited in a \nfilter, to be analysed as under 4. Meanwhile the sand is to be \nexamined, and its quantity registered. It is either calcareous \nor siliceous ; and its nature may mostly be detected as that of \nstones and gravel, without a minute analysis. If it consist whol- \nly of carbonate of lime, it will rapidly dissolve in muriatic acid, \nwith effervescence ; but if it consist partly of this, and partly of \nsiliceous sand, the latter will be found unchanged after the acid \ndissolving the lime has ceased to effervesce. This residuum \nmust be washed, dried, and heated strongly in a crucible. Its \nweight is then ascertained by the balance ; and that, deducted \nfrom the weight of the whole, indicates the quantity of calcare- \nous sand dissolved. \n\n4. Analysis of the Finkly-divided Matters. \xe2\x80\x94 The \nwater passing through the filtre is to be preserved ; for if any \nsaline particles or soluble animal and vegetable elements exist- \ned in the soil, it will be, found to contain them. Meanwhile the \nfine solid matter^eft on the filter must be collected, and dried. \nThis is usually a compound exceedingly multifarious ; it some- \ntimes contains all the four primitive earths, as well as animal \nand vegetable matter. To ascertain the proportions of these \nwith tolerable accuracy, is the most difficult part of the assay. \n\nI. Test of Lime in a Solid State. \xe2\x80\x94 Of muriatic acid \ntake twice the weight of the promiscuous soil ; and dilute the \nacid with double the measure of water. Let the mixture remain \nfor an hour and a half, stirring it frequently. \n\nBy this time, if any carbonate of lime or of magnesia existed \nin the soil, they will have been dissolved in the acid ; which \nsometimes takes up likewise a little oxide of iron, but very \nseldom any alumina. \n\nThe fluid should be passed through the filter. Then let the \nsolid matter be collected, washed with rain water, dried under \na moderate heat, and weighed. The loss denotes the quantity \nof solid matter taken up. \n\nII. Test of Ikon. \xe2\x80\x94 Add the washings to the solution, which, \nif not sour to the taste, must be made so by the addition of fresh \n\n\n\nTESTS OF SOILS. 19 \n\nacid. The test now to be added to the whole, is some triple so- \nlution of prussiate of potassa and iron. If a blue precipitate oc- \ncurs, it indicates the presence of oxide of iron ; and more of the \ntriple solution must be dropped in till this effect ceases. In or- \nder to weigh the precipitate, it must be collected and heated red. \nThe result is oxide of iron, with perhaps a little oxide of man- \nganiisum. \n\nIII. Test of Lime suspended in a Fluid : \xe2\x80\x94 also of Mag- \nnesia. \xe2\x80\x94 Having taken out all the mineral oxide, next pour into \nthe fluid a solution of neutralized carbonate of potassa, continu- \ning to do so until it will effervesce no longer, and- till both the \ntaste and smell of the mixture indicate an excess of alkaline \nsalt. \n\nThe precipitate that falls down is carbonate of lime : it must \nbe collected on the filter, and dried at a heat below that of red- \nness. \n\nThe remaining fluid must be boiled for a quarter of an hour; \nwhen the magnesia, if any exist, will be thrown down, combined \nwith carbonic acid. To bring it into a state for being weighed, \ntreat it as the carbonate of lime.* \n\nIV. Test of Alumina incidentally dissolved and pre- \ncipitated. \xe2\x80\x94 If any minute proportion of alumina should have \nbeen dissolved by the acid employed in the first test, it will be \nfound with the carbonate of lime in the precipitate obtained by \nthe third. To separate it from the carbonate of lime, boil it for \na few minutes with as much soap lye, or solution of caustic so- \nda, as will cover the solid matter. Soap lye thus applied dis- \nsolves alumina without acting upon carbonate of lime. \n\nv. Measure of the Matter destructible by Red- \nIHEAT. \xe2\x80\x94 After the finely-divided promiscuous soil has been act- \ned upon by muriatic acid, the next step is to ascertain the quan- \ntity of insoluble animal and vegetable matter which the residu- \num contains. \n\nSet it in a crucible over a common fire ; and let it be ignited \ntill no blackness remains in the mass ; stirring it often with a \nmetallic rod so as to expose new surfaces successively to the air. \nThe loss of weight ultimately caused, shews the quantity of sub- \nstance destructible by fire and air. \n\nWhen the smell emitted during the incineration resembles \nthat of burnt feathers, it is a certain indication either of animal \n\n\xe2\x80\xa2 In case the soil be sufficiently calcareous to efTervesce very strongly with \nacids, ProfeSsoi- Davy gives us a method of measuring the quantity of carbon- \nate of lime, by collecting the carbonic gas expelled by the acid in a pneumatic \napparatus described verbally in the Lectures, p. 116. This gas is to be either \nmeasured or weighed ; and it will bear the proportion of 43 to 100 to the ori- \nginal weight of the carbonate of lime. This may be a very simple process to \nan expert chemist; but it is neither so easy to describe, nor so cheap to practice \nin occasional experiments, as that above. In an outline like this, for popular \nuse, it is therefore sufficient to notice it. \n\n\n\n20 TESTS OF SOILS. \n\nmatter or of some substance analogous to it : on the other hand, \na (.opious blue flame unitormly denotes a corresponding propor- \ntion of vegetable rudiment. It will accelerate the destruction \nof matter decompcjsable by ignition, to throw gradually upon \nthe heateu mass some nitrate of ammonia, in the proportion of \none-fifth to the weight of the residual soil. \n\nVI. Separation of the Parts indestructible by Heat. \n\xe2\x80\x94 The remaining parts are generally minute atoms of earthy \nmatter, comprehending alumina and silica, combined with oxide \nof iron, or of manganesum. \n\nTo separate these, boil them in little more than their weight \nof sulphuric acid, diluted with four times its weight of wa- \nter. \n\nThe substance keeping a solid form after this treatment, may \nbe considered as siliceous. Let it be collected on the filter, \nwashed, dried, and wtighed. \n\nIf the residuum contained any oxide of iron, or of mangane- \nsum, ihey will have been dissolved by the sulphuric acid. To \nthrow down the oxide of iron, add in excess succinate of am- \nmonia. Whrn this has been done, introduce soap lye, to dis- \nsolve the alumina, and to precipitate the oxide of manganesum. \nHeat the oxides to redness, and then eigh them. \n\nShould any magnesia and lime have escaped solution by the \nfirst test, that of muriatic acid, (which is rarely the case,) they \nwill be found in the sulphuric acid. Their quantities are ascer- \ntained by a similar process to that above. \n\n(Course sometimes substituted for "v. and vi." \xe2\x80\x94 If \nvery great accuracy be the object, dry carbonate of potassa must \nbe -mploved as the agent ; of which four times the weight of \nthe subject must be put with it into the crucible, and heated red \nfor half an hour. The mass indestructible by heat must then \nbe dissolved in muriatic acid, and the solution evaporated till it \nis nearly solid. In this state, add to it distilled water, by which \nthe oxide of iron, and all the earths, except silica, will be dis- \nsolved in combination as muriates. The silica, after filtration, \nmust be heated red. The other substances are separated as from \nthe muriatic and sulphuric solutions above. Where the soil to \nbe analysed contains stones of doubtful composition, this pro- \ncess is well fitted to determine their charactt-r.) \n\nVII. Evaporation of the Digesting Water. \xe2\x80\x94 The wa- \nter first used for boiling the earth as under L 3. (and which was \ndirected to be kept for a separate trial) will contain whatever sa- \nline matter, or soluble vegetable and animal rudiments, existed \nin the soil. \n\nThis water must be evaporated to dryness at a heat below \nboiling. \n\nIf the solid matter obtained be brown in colour and inflam- \nmable, it may be regarded as vegetable extract, unless in com- \n\n\n\ntESTS OF SOILS. 21 \n\nbastion it emit a smell like tnat of burnt feathers, which indi- \ncatts animal or uiouminous matter. If any portion be white, \ncrystalline, and not destructible by heat, it may be considered as \nsaline m its properties. The saline matter altogether bears a \nmuiute proportion to the other constituents; and as most of it is \ngenerally common salt, the following tests need seldom be re- . \nsorted to. Salts of potassa are thrown down by a solution of \nplatina. Sulphuric acid combined with any salt is detected in a \nsolution of baryta by a dense white precipitate. Salts of lime \nassume a cloudy appearance in a solution containing oxalic acid. \nSalts of magnesia cause a similar cloudiness in a solution of am- \nmonia. Muriatic acid is discovered by forming clouds in a so- \nlution of nitrate of silver. Salts containing nitric acid sparkle \nwhen thrown on burning coals. \n\nVIII. Process for detecting Sulphate of Lime, and \nPhosphate of Lime. \xe2\x80\x94 Sulphate of Lime (Gypsum) is to be \ndetected by another independent process ; on which is engrafted \na method of \'getting at Phosphate of Lime in a separate state. \nFirst, put the residuum, with one-third of jts weight of powder- \ned charcoal, into a crucible : and heat the mixture red for half \nan hoar. The mass is afterwards to be boiled in water, (half a \npint to 400 grains,) for a quarter of an hour. Filter the whole : \nexpose the collected fluid for some days to the atmosphere ; and \nso much gypsum as the soil comprised will be gradually depo- \nsited as a white precipitate. \n\nThen to separate the Phosphate of Lime from the solid resi- \nduum, digest upon it muriatic acid more than sufficient to satu- \nrate the soluble earths. Evaporate the solution, and pour wa- \nter upon the remains. The result will dissolve the earthy com- \npounds, and leave the phosphate of lime untouched. \n\nWhen Sulphate of Lime and Phosphate of Lime have been \nthus disengaged in a solid form, it is sometimes necessary to de- \nduct a sum equal to their weight from the amount of the Car- \nbonate of Lime ; but that is only when the latter has been cal-> \nculated by the loss sustained in solid matter, part of which en- \nters into the new compounds from which the Sulphate and Phos- \nphate have been recovered. \n\nIX. Formula for recapitulating the Results. \xe2\x80\x94 When \nthe analysis of a soil is finished, add the quantities together ; \nand if they nearly equal the original portion of soil,* the assay \nmaybe confided in as accurate. \n\nFour hundred grains of a good siliceous sandy soil from a hop \ngarden near Tunbridge, Kent, gave these results : \xe2\x80\x94 \n\nGrains \n\nWater of absorption -...19 \n\nIioose stones and gravel, chiefly flinty -.\xe2\x80\xa2..- S3 \n\nCan-ied over, .... - 72 \n\xe2\x80\xa2 Elements of Agricultural Chemistry, p. 120. \n\n\n\n32 CORRECTIVES OF SOIL&. \n\nBrought forward, . - - . 72 \n\nUndecomposed vegetable fibres 14 \n\nFine siliceous sand ---- 212 \n\nS.i. /\'Carbonate of lime 19 \n\n1 1 1 Carbonate of magnesia --..... 3 \n\n"3 s 1 Matter destructible by heat, chiefly vegetable - - . 15 \n\n:|^s J Silica 21 \n\n^3*5"% Alumina ..--......13 \n\n\xe2\x80\xa2J a J Oxide of iron --........ S \n\ng 2 m Soluble matter, principally common salt and vegetable extract 3 \n\n\xe2\x80\xa2gS* V^Gypsum ..---.-..- 2 \n\nLoss \xe2\x80\xa2 - 21 \n\n. 400 \n\nX. Popular Application or DEt ached Steps in the Pro- \ncess. \xe2\x80\x94 The assay may be very much simplified, when the inqui- \nry is confined to one leading object. Thus, il it be merely wish- \ned to know, whether a soil contain already so much lime as to \nmake it inexpedient to bring on lime as a manure, it will be \nenough to put the specimen into a dish, and to pour upon it a \nquantity of muriatic acid : indeed when no other experiment is \nto be grounded on this trial, good white-wine vinegar may be \nemployed. If the soil immersed in acid effervesces strongly, it \nis sufficiently charged, or perhaps overcharged, with lime. In \na similar way, one or two essential questions may be sometimes \nsolved by resorting to any of the other tests, either alone, or two \nor three connectedly, in a different order from that which has \nbeen set down. \n\n\n\nCORIlECTIVliS OF ILL-CONSTITUTED SOILS. \n\nThe following are simple and efficacious correctives of some \nbad ingredients in soils, or the excess of some good constituent; \nthe presence of which frequently disappoints even the skilful \ncultivator, when either the true cause is not suspected, or an ap- \npropriate remedy is not known. \n\n1. A farmer with a great portion of common skill is often baf- \nfled by Iron in its acid combinations. If on washing the \nspecimen of a sterile soil, it is found to contain the Salts of \nIRON, Sulphate of iron, or any Acid matter, it may be \nameliorated by a top-dressing of quick lime ; which converts \nthe sulphate of iron (copperas) into a manure. \n\n2. If there be an Excess of pure calcareous matter \n(<JHALK OF lime) in a soil, its constitution maybe improved by \nturning in, in a green state, some of those vegetables which pos- \nsess the greatest quantity of acid; also by the application of sand \nor of clay, with a small proportion of oxide of iron (blacksmith\'s \nsweepings) not exceeding ^^ part. The same object may be ob- \ntained by irrigating with any calybeate water (water containing \n\n\n\nCORREqTIVES OF SOILS. 23 \n\niron,) or by the addition of peat containing vitriolic (i. e. sul- \nphuric) salts ; both which are calculated to turn lime or chalk \ninto gypsum.* See under VIL 5. why gypsum is sometimes \nbeneficial and sometimes not. \n\n3. When an Excess of carbonate of lime (charcoal uni- \nted to lime) requires the quality of the soil to be modified, gyp- \nsum applied as a manure, also oxide of iron applied as a cor- \nrective, seems to produce the very best effects. Carbonate of lime \nis mild lime in cumbination with charcoal absorbed from decay- \ned vegetable or animal matter. The diversified effects of lime \nas a manure are explained under VII. 1. \n\n4. Soils REDUNDANT IN SAND are benefited by a top dressing \nof peat or other vegetable matter, or of decayed animal matter, \nor by a mixture of clay. Also, if the sand be not calcareous, \nby marie. \n\n5. An Excess of vegetable matter is to be removed ei- \nther by burning, (See III. Paring and Burning^ or by the ap- \nplication of earthy materials. The fundamental step in the im- \nprovement of peat land, or a bog or marsh, is draining. Soft \nBLACK peats, after being drained, are often made productive \nby the mere application of sand or clay, as a top dressing : sand \nis greatly to be preferred. When peats are acid, or contain \nFERRUGINOUS SALTS, calcareous matter is absolutely necessary \nin bringing them into cultivation. When they abound in the \nROOTS AND branches OF TREES, the wood must either bc grub- \nbed up and carried off, or destroyed by burning ; so when the \nface of peat is incumbered by living plants containing much \nWOODY FIBRE, and therefore not proper to be ploughed in the \nground, the field must be cleared l;y one of thf same methods. f \n\n6. Where there is a redundancy of clay in a soil, (and if \nthe quantity of clay exceed one-sixth of the general mass, it is \ndesirable to reduce the proportion,) one of the best dressings \nwhich can be applied is a mixture of sand and mild lime; the \nrubbish of mortar containing both these materials, is an excel- \nlent thing to improve the texture of a clayey soil. Clay appears \nto receive no improverrvent from lime alone. Sea-sand may he \nused alone with good effect. It would be also highly beneficial \nto introduce as much fermented dung or decayed vegetable mat- \nter as would entitle the land to the denomination of a loam. \n\nII. Bij Draining. No perennial crops, and but few annual \nplants, can be successfully cultivated where the land is exposed \nto winter floods, or Vv\'here the subsoil is rendered wet by under- \nsprings, or by heavy leakage from neighi)ouring pieces of water \nlying higher and imperfectly banked off. The importance ol \n\n\n\n* Elements of A\'^TicultinV, (;lir\'tT)istrv, p. 141, 2-5. \nt Ibid, p- 142. \n\n\n\n24 PARING AND BURNING. \n\ndraining peat land has been adverted to under I. 5. Where \nopen drains woujd he unsightly or inconvenient, as in the inte- \nrior of a domestic garden, or ornamented ground, a paved \nbrick drain is in the end cheaper than a rubble drain, because \nthe latter is liable to be soon choked by the roots ot" trees. \n\nIII. By Paring and Burning. It is obvious, that in all ca- \nses the process of Burning must destroy a certain quantity of \nvegetable matter ; and it must principally be useful where an \nexcess of this matter renders the soil too rank. It must be of \neminent service in reducing to charcoal, or wood ashes, a great \naccumulation of woody fibre already overrunning the field ; for \nwoody fibre is very slowly reduced to the state of vegetable \nmould, if left to the process of a natural dissolution : nor is it \nvery rapidly reduced by lime or other solvents artificially ap- \nplied. \n\nBurning likewise renders clays less coherent ; and in this \nway greatly improves their texture, and causes them to be more \npermeable to water,* and consequently, less retentive of it in \nstagnant masses. Another cause of the unproductiveness of \ncold clayey adhesfve soils, is, that the seed is coated with mat- \nter impenetrable to air.f When clayey or tenacious soils are \nburnt, their power or tendency to absorb water from the atmos- \nphere is diminished in the proportion of 7 to 2 ; and they are \nbrought nearer to a state analagous to that of sands ; the parti- \ncles are less adhesive, and the mass less retentive of moisture. \nThus the process of burning, properly applied may convert a \nmatter that was stiff, damp, and in consequence cold, into one \npowdery, dry, and warm ; altogether more fitly constituted as \na bed for vegetable life. The great objection made by specu- \nlative Chemists to paring and burning is, that the animal and \nvegetable matter in the soil is diminished : \xe2\x80\x94 But where the tex- \nture of the earthy ingredients is permanently improved, thert \nis more than a compensation. To meet the objection still more \ndii\'ectly, where an excess of inert vegetable matter is present, \nthe destruction of a part of it must be beneficial ; and the car- \nbonaceous matter in the ashes may be more useful to the crop, \nthan the unreduced vegetable fibre, of which it is the remains,^ \ncould have been. \n\nThe most speedy way of bringing under tillage a meadow \noverrun with rushes is ; first to drain it, and then to pare oft \na thick turf and burn it. \n\nThe cases in which burning must incontestably be prejudi- \ncial, are those of sandy dry flinty soils containing little ani- \nmal or vegetable matter : here it can only be destructive ; icK \n\n\' Klements of Agricultural Chemistiy, p. 22. \nt Ibid. p. 149. \nt Ibid. p. 234. \n\n\n\nTURNING-IN GUEEN CROPS. 2^5 \n\nit decomposes that constituent which is already below the mini- \nmum proportion, and on the presence of which, in a limued de- \n\xe2\x80\xa2 gree, the productiveness of a soil depends.* \n\n" Burning without fire." A new method has lately been \ndiscovered of substituting quick lime for fire ; and experiments \nmade upon it before the Workington Agricultural Society gave \ngeneral satisfaction. The lime in its most ciustic state, fresh \nfrom the kiln, is laid upon the vegetable surface to be consumed ; \nand before it is weakened by exposure to the air, water, just in \nsufficient quantity to put it powerfully intp action, is applied. \nThis fierce compound will not only consume the vegetable co- \nA\'ering, but affects the clay, or other upper stratum, as if it had \nbeen in contact with fire. It supersedes the trouble which has \nhitherto attended burning ; and in respect to poor soils which \n\xe2\x80\xa2would be improved by the two distinct operations of burning \nand liming in the common mode, it bids fair to bring them \nsooner on a par with those of superior quality. \n\nIV. By Tiirnhig-in Green Crops as Manure, \xe2\x80\x94 This is di- \nrectly opposed to Burning Turf, in regard to intention and ef- \nfect I and is particularly serviceable where the basis of vegeta- \nble mould is to be augmented, being an extension of the prin- \nciple on which Paring Turf without Burning is resorted to. \xe2\x80\x94 \nWhen Green Crops are turned into the clod, besides enriching \nthe staple with nutritive matter, they promote the fermentation \nand decomposition of woody fibre buried near the surface ; and \nwhich is a useless incumbrance in an undecayed state. \n\n" When GREEN CROPS are to be employed for enriching a \nsoil, they should be ploughed in, if possible, when in flower, or \nat the time when the flower is opening ; for in this stage, they \ncontain the largest quantity of soluble matter. Green Crops, \npond-weeds, the paring of hedges or ditches, or any kind of \nfresh vegetable matter not woody, require no preparation! to \nbe fitted for manure. When old pastures are broken up for til- \nlage, not only is the soil enriched by the death and slow decay \nof the plants which have previously deposited soluble matters \nin the clod ; but the leaves and roots of the grasses (vegetating \njust before the change of culture) afford saccharine, mucilagin- \nous, and extractive matters, which become hnviecUutelu the food \nof tlie crop J also the gradual decomposition of the grasses af- \nfords a supply of vegetable mould for several years. ^\'\' \n\nAfter giving the substance of Sir H. Davy\'s theory on any \n\nspecific subject in agriculture, it will not be often necessary to \n\nncur the hazard of questioning some incidental deduction from \n\nae system; because the principal branches of his theory are so \n\n)nsonant with experience, that they incontestJbly contribute \n\nound and intelligible principles for applying more extcnsivelv, \n\n\xe2\x80\xa2 Elements of Agricultuial fihemistw, p, 22. \n\n\n\n26 lALLOWlNtJ. \n\nand with niuie certain eilcct, entire classes of means at the \nct)ui.iiand of the culti\\\'atur, \xe2\x80\x94 where the resources to which \nthe practical larmer had arrived, by the empirical course \nof laying different ingredients on land without knowing ttieir \nprecise operation, were previously few and limited, or their \nutility doubtful. \n\nBut in regard to the effect of vegetable matters as ma- \nnures, there is a vein of doctrine jjervading the theory ol this \ngreat chemist, which seems to l)e taken up independently of ex- \npjixience, and without calculating all the principal relations be- \nlolfging to the subject : \xe2\x80\x94 which doctrine is*, that to bury vegeta- \nble manure without\' fermenting, and leave it gradually to de- \ncompose in the soil, will prolong its fertilizing power for \nseveral se^isons. So it will : \xe2\x80\x94 but what will be the intermedi- \ns^t state of the soil ? Surely the capacity of the land for grow- \ning healthy jilants cannot be equal to that of a clean soil where \nthe manure is not applied till it is ready to afford nutriment. \n\nThis part of the theory is in opposition to the practice of \nrotting turf before it is turned into the soil, or of waiting till it \nhas become rotted before a new crop is introduced. There \nwill be several occasions of adverting to this principle again^ \nand of viewing every side of it as it may catch different lights \nin different positions, particularly under Sect. V. By Follow- \nini[>\\ and the head Management of Manure from the \nHomestead. j \n\nV. Bif Fallorving. \xe2\x80\x94 Sir Humphry Davy seems to under-rate \nthe utility of fallowing, and to be disposed to recommend the \nnon-fallowing system. \n\nThe following is the substance of the observations occurring \nin different j^arts of his Work on this subject. (1st.) \'* The \nchemical theory of fallowing is very simple. Fallowing affords \nno new source of riches to the soil. It merely tends to pro- \nduce an accumulation of decomposing\' matter . which in the com- \nmo7i course of crops xvoiild be employed as it is formed ; and it \nis scarcely possible to imagine a single instance in which a culti- \nvated soil can lie fallow for an entire vear with advantage to \nthe farmer. The only cases where this practice is beneficial \nseems to be in the destruction of weeds, and for cleansing foul \nsoil ^ \n\n"\xe2\x80\xa2 i\'lie benefits arising from fallows have been much over- \nrated. A suinmer fallow, or a clean fallow, may be sometirnes \nnect-ssury in lands overgrown with ^veeds, particularly if they \nare sands, \xe2\x80\x94 which cannot be pared and burnt with advantage: \nbut it is certainly unprofitable as part of a general system of \nhustiandry."! , \n\n(2dly.) " It has been supposed hy some writers, that certam \n\n* Elemcvits of AgTicultural Chemisty, p. 22. \n\ntlbid,2?9, \n\n\n\nFALLOWING. 27 \n\nprinciples necessary to fertility are derived from the atmos- \nphj-rc, .viu;.h are uXiaasted by a succession of crops, and that \nthese are again supplied duriiig the repose of the land, and the \nexposure of the pulverized soil to the influence of the air : but \nthis, in truth, is not the case. The earths commonly found in \nsoils cannot be combined witn more oxygen ; none of them will \nunite to azote ; and such of them as are capable of attracting \ncarbonic acid, are always saturated with it on those soils on \nwhich the practice of fallowing is adopted. The vague ancient \nopinion of the use of nitre, and of nitrous salts in vegetation, \nseems to ha -e been one of the principal speculative reasons for \nthe defence of summer fallows. Nitrous salts are produced \nduring the exposure of soils containing animal and vegetable \nremains, a id in greatest abundance in hot weather : but \nit is PROBABLY by the com!)ination of azote, escaping from \nthose remains, with oxygen in the atmosphere that the acid is \nformed ; and at the expense of an element v/hich would otlier- \nwise have been converted into ammonia; the cosnpounds of \nwhich, as is evident from what is stated under VIII. 2, are \nmuch more efficacious than the nitrous compounds in assisting \nvegetation."* \n\n(3dly.) " When weeds are buried in the soil, by their gra- \ndual decomposition they furnish a certain quantity of soluble \nmatter: but it may be doubted, whether there in as- much use- \nful manure in the land at the end of a clean falloxv^ as at the \ntime the vegetables clothing the surface were first ploughed in. \nCarbonic acid gas is formed during the whole time by the action \nof the vegetable matter upon the oxygen of the air ; and the \ngreater part of it is lost to the soil in which it -was formed^ and \ndissipated in the atmosphere. \n\n" The action of the sun upon the surface of the soil tends to \ndisengage the gaseous and tnt- volatile fluid matters contained \nin it ; and heat increases the rapidity of fermentation : and in \nthe summer fallow^ nutriment is rapidly produced at a time \nwhen no vegetables are present capable of absorbing it."f \n\n(4thly.) "\xe2\x96\xa0 Land when it is not employed in preparing food \nfor animals, should be applied to the preparation of manure for \nplants ; and this is effected bv means of green crops, in con- \nsequence of the absiorption of carbonaceous matter from the \ncarbonic acid of the atmosphere. In a summer^ s falloxv^ a pe- \nriod is always lost in which vegetables may be raised, either as \nfood for ani rials, or as nourishment for the next crop ; and the \ntexture of the soil is not so much improved by its exposure as \nin winter, when the expansive powers of ice, the gradual dis- \nsolution of snows, and the alternations from wet to dry, tend to \npulverize it, and to mix its different parts together.":|; \n\n* Elements of Agricultural Chemistry, p, 240. \ntTb.id. ^ Ibid. \n\n\n\n2H TALLOW IN tt. \n\nThe Reader has now before him the arguments directed hy \nSir H. Davy against the praetice ot fallowing, as part of a ge- \nneral system of husbandry. \n\nBut cannot some of the above object;ions to the giving of a \nperiodical rest to land after an exhausting crop be obviated ? \nand are not the benelits of a summer fallow, when admitted to \nbe necessary, in some respects undervalued ^ \n\nIn the first place, this eminent philosopher observes, that fal- \nlowing " MERELY tends to produce an accumulation of decom- \nposing matter, which in the common course of crops would be \nemployed as it is formed.\'" But this accumulation of decom- \nposing matter is alone a great acquisition ; it is in many cases \nthe precise restorative wanted to keep up the proportion oi ve- \ngetable mould necessary to fertility. Supposing the milder \ncourse of crops to employ the decomposing matter as it is \nformed, \xe2\x80\x94 how are plants which depend still more on the nutri- \nment lodged in the :-.oil, to be grown in full crops, where the \nquantity of manure is limited by local circumstances, unless \nthe elements of vj:getation are allowed to accumulate for a sea- \nson, at periods adjudged proper by a manager acquainted with \nthe power of the soil and the course of crops ? \n\nSecondly, in opposition to the idea that certain principles ne- \ncessary to fertilit)- are derived from the atmosphere. Sir Hum- \nphry enters on a speculative train of reasoning, \xe2\x80\x94 against which \nit would be presumptuous to appeal, had he offered a positive \nconclusion as a great chemical authority : but some of the as- \nsumed data \xe2\x80\x94 such as that the " earths commonly found in soils \ncannot be combined with more oxygen" \xe2\x80\x94 seem to skirmish with \nthe conclusion [" Nitrous salts". . . to the end of the para- \ngraph ;] \xe2\x80\x94 nor has the " vague ancient opinion of the use of nitre \nand of nitrous salts in vegetation\'\' been subverted or discoun- \ntenanced b)- the experiments of modern physiologists, many of \nwhom have found that plants will grow in nitre alone, which is \nmore than the ancient opinion requires in its support. And as \nto the final inference, \xe2\x80\x94 " but it is probably by the combina- \ntion," &c. the uncertainty disclosed in the word " probably," \ndeprives the argument ot all decisive effect in a practical point \nof view for although the Professor is acquainted witl\\ the ope- \n. ration of gases as far perhaps as experiment will ever trace it^ \nthe manner in which nitrous salts are produced in soils contain- \ning animal and vegetable remains, is but guessed at by him, and \nnot explained to us with the authority of certain knowledge. \n\nThirdly, this distinguished Chemist, after virtually admit- \nting, that the weeds which were overrunning the land must en- \nrich it by being buried in its bosom, further observes : \xe2\x80\x94 " But \nit may be doubt r.D, whether tliere is as much useful manure in \nthe land at the end of a clean fallow, as at the time the vegeta- \nbles clothing the surface were first ploughed in." . , . he Scj:. \n\n\n\nFAI.LOWIXG\'. 29 \n\nTo this speculative objection the answer must necessarily \ntake a speculative turn. \n\nIf there be less manure in the land at the dose of a fallow, \nthe quantity lost must have escaped in the shape ot vapour, and \nbeen dispersed in the atmosphere. It may be wortii while t(j \ninqvjire how far this is to be estimated as a loss i \n\nIn opposition to the theory of Sir Humphry Davy on this \npoint, it is quite consistent with good logic to suppose, that \nwhatever escapes from the dissolviu)^ mass of a dead plant in \nthe form of vapour, and does not fall down to the earth by con- \nlensation, is easily and most naturi.lly taken up by a new grow- \nnj; plant from the atmosphere, throu;i;h the leaves ; that is to \n^ay, whatever has^ tendency to fly oil\' into the air is to be re- \n\';ovcred by communication with the air. \n\nOn this subject the theory of the author of these remarks is \nas Ibllows : \xe2\x80\x94 \n\nTo form the bulk of a growing plant, \xe2\x80\x94 certain Substances \ncomprehended under some of the descriptions of matter com- \nmon to vegetables, and which appear on analysis to be combined \ndifferently in different\' species, are taken up by the roots from \nthe soil, and by the leaves from the air, tlirough the medium of \ncongenial fluids : in succulent plants a greater proportion of \nfood is received by the leaves than by the roots, so that even \nthe bulk of the plant, or the basis of the sap, is in such kinds \nincreased chiefly by derivations from the air. \n\nTo imbue a common insipid basis with those distinguishing \npeculiarities which make different species growing in the same \n,oil differ in scent, flavour, and the qualities which are salutary \nor pernicious in food and medicint, \xe2\x80\x94 certain Specific Essen- \nces, or volatile aeriform atoms, invisible either from being co- \nlourless or minutely divided, are taken up entirely by the leaves \nfrom the air; the character of the plant having been originally \nfixed by a portion of the peculiar essence being lodged in the \nseed so as to attract to it only volatile particles of its own na- \nture.* \n\nH\';nce in mixed masses of manure, the manure may be con- \nsidered better adapted for general purposes, when the volatile \nproperties peculiar to specific plants and to animal bodies have \n::scaped, and when the residuum is nothing more than the mat- \nter common to vegetable and animal bodies. \n\nIt may seem to be a loss, that the gaseous essence, escaping \ninto the atmosphere, is dispersed over an immeasurable region \nof air, and carried by winds over the face of the earth, instead \nof being retained for the enrichment of a particular field. To \n\n\n\n\xe2\x80\xa2 \'I\'liis tlicon\' will f^o a considerable way towards afTording a solution why \nJic hlossoms and fruit of" a graft should preserve their distingiiishinjj pcouliari- \n.ics, unaltered by connexion with the stock* \n\n\n\nso FALLOWING. \n\nthis it may be answered, that che ^ases of which the air is con- \nstitued \xe2\x80\x94 oxygen, azote, and carbonic acid gas \xe2\x80\x94 though differing \nin ilieir specific gravity ar rather levity, arc found to be com- \nbined in any cubical quantity of air in a proportion which ne- \nver materially varies ;* and it is quite reasonable to suppose, \nthat the volatile salts or spirits, or aromatic principles, which \nconstitute the essences of plants, arc distributed equally over \nthe atmosphere by the same law. The quantil^ of volatile essence \nfloating within reach of the attraction ol an individual plant must, \n^indeed, be allowed to be evanescent even to the confines of no- \nthingness, when the transparency of the air is considered, and the \ntnultiplicity of difl\'erent essences of which infinitel) small divi- \nsions are supposed to be floating in it. But if^on the other hand, \nwe advert to the elastic nature of the air, and the jiroperty \nwhich it is found to have ot always preserving its natural equi- \nlibrium, the most scanty provisions of volatile food in the vici- \nnity of a plant is abundance. Thus, suppose a plant to take up \ncarbonic acid gas with great avidity ; although the proportion of \ncarbonic acid gas is extremely small, yet the plant cannot drink \ntip the quantity in immediate contact so fast, but the same quan- \ntity will be constantly preserved in the air surrounding it ; for \ngas of the same nature is incessantly pressing into the temporary \nvoid where the interchange of natural air is unrestricted. The \nsupply of a peculiar essence to plants, by the medium of the \ncommon air, may be rendered sufficiently ample by obedience \nto the same law. \n\nIt may therefore be one of the benefits of a fallow, to lose \nevery thing which can escape by a free exposure of the putrefy- \ning remains which promiscuously accumulate in a soil. \n\nOn the hypothesis which has just been sketched, the objec- \ntion of Sir H. Davy, that " the action of the sun upon the sur- \nface of the soil tends to disengage the gaseous and the volatile \nfluid matter that it contains, and heat increases the rapidity of \nfermentation," \xe2\x80\x94 may be enlisted among the arguments in favour \nof a summer fallow. In cases where a restorative course is de- \nsirable, the objector also becomes an ally who urges, that " in \nthe summer fallow nutriment is rapidiiy produced at a time \nwhen no vegetables are present capable of absorbing, it." \n\nFourthly, with regard to the superior utility of ploughing in \nGreen Crops, as recommended in the Elements of Agricultu- \nral Chemistrv, instead of a fallow : \xe2\x80\x94 There can be no difference \nof opinion where the land is poor, or exhausted, without being \nfoul; that is to say, when it wants recruiting with manure, but not \ncleaning of root-weeds to the full depth of the soil. Plants which \nquickly decompose, such as the lettuce, are most conducive to \n\n* In a given volume of air, their pro^jortions arc usually found to be : Oxygen \n3^^ ; azote J^^ ; carbonic acid gas ^^^ max. ^^^ min. \n\n\n\nFALLOWING. 31 \n\nihe object of exciting a fermentation in fibrous woody remainis \nas well as enriching the land. This subject has been already \ntouched under Sect. IV. \n\nTo return to \'the question of fallowing. It is merely to dis- \nembarrass the practical manager, that so much has been said by \nway of theory against an hypothesis on non-JflUowing^ which \nis made to depend on assumptions from chemical principles \ntoo little capable of proof from experiment to be safely adopted \nin this branch of agriculture. \n\nSome of the incidental statements, in the above abstract from \nthe Professor\'s Lectures, are decidedly adverse to practical \nmaxims in which most farmers, and the majority of writers on \nhusbandry, including the Reports from Agricultural Societies, \nconcur ; \xe2\x80\x94 the statements, for example, that \' sands are benefited \nby a summer fallow more than clays ;\' and that the \' land is not \nricher at the end of such a fallow than it was before.\' On the \ncontrary, the conclusion to which the registered courses of pro- \nfitable husbandry lead, is very much like the following sum- \nmary. \n\n1. Land is uniformly recr^iited during a fallow : this is pro- \nved by the circumstance, that, in all soils, a much leas quantity \nof dung is necessary after a sutnmer fallow ; and on some lands \nnone is wanted ; nay, the experienced Cally is of opinion, that \ndunging naked fallows is in many cases better dispensed with, \nand has often, in tolerable loam^, made the crop to fail. \n\n2. Clays are unfit for green crops, the substitute for a sumr \nmer fallow ; and hence are necessitated to adopt the latter, in \nrotation with white crops.* A winter fallow merely is, indeed, \nan excellent thing in light grounds, and as a preparation for \nspring wheat ; but it will not do with clays, which require a \nthorough drying and pulverizing, before they can profit by the \nfalling juices, which would only render the earth more hard and \ncompact. A summer fallow is, therefore, more proper for this \nsoil.f \n\n3. Light soils only can dispense with fallows. The ques- \ntion therefore is narrowed to this compass : Whether the benefit \nof a summer fallow, on a sandy or other light soil fit for green \ncrops, is equal to the loss of a year\'s rent\xc2\xbb or to the difference \nbetween the profit of a green crop and the rent for one year \npaid on a naked fallow ? The general conclusion is, \xe2\x80\x94 that it i? \nnot ; and that a summer fallow for light soils is too costly. \n\nBy a rotation of crops, every ingredient in the manure ap- \nplied is successively turned to profit; for those parts of it \nwhich are not fitted for one crop remain as nourishment for \nanother. \n\n\xe2\x80\xa2 Letter by tlie President of the Workington Agricultural Society, dated TSav, \n2D, 1814. \n\nt Pfiilosophical Magazine for Jan. 1815. A<>. 1. p. 12. \n\n\n\nIJ2 FALLOWING. \n\nDifferent soils refiuJrc a diiriient rotation, and the ])vacttce of \none district allord no ubsolutr rule lor another. Local circiim- \nrilances will always nilluenci- the course of crops ; jet a survey \nof some of" the rotati(jns, which alter long trial are found lo be \nrepeatedly beneficuil on the principal sorts (<f land, tends lo en- \nlarge the resources of farming ; and if brought from a distant \npart of the island, the chance of" a benificial exchange of infor- \nmation, in some respects new, is increased. \'J\'lie following \ncoinii.unioations are gathered from a voluminous w()rk, entitled \n(unicral Ril)ort oj\' the Ai^-riculturc of Scolland^ published under \nthe superniteiidanee ol bir John Sinclair. \n\nBknkj IT oi\' (jRCKN Cuoi\'s. \xe2\x80\x94 " \'\'I\'he introduction of Turnips \nand Clover has been the means of" rendering productive those \ninferior soils which it was impossible to cultivate under the old \nsystem of successive corn crops. Even on land of a better \nquitlity, the crops which succeed these are so much more abun- \ndant, that it is probable as many bushels of corn now grow on \nthe half of a given extent of ground as were formerly raised\' \non the whcile. In this vie w alone, almost the whole value of \nthe turnips and clover may be said to be a clear gain. Fallow \nhas been banished from all dry soils by turnips ; and where land- \nis laid down to pasture, one acre of cloVer and rye-grass will \nfatten more cattle than could barely exist on ten acres left full \nof weeds to be casually sown, after several years, with natural \ngrasses. \n\n" When turnips were first introduced on farms, and for some \ntime after, the most common apj^lication of them was to the \nfattening of cattle. Sheep did not then form any important \npart of the stock of arable land : but on light soils the full be- \nnefit of this crop was not ol)tained, until it had become the. \npractice to consume the greater i)art of the crop on the ground \nby sheep. The poorest sandy soils seldom fail to yield an abun- \ndant croj) of corn after turni])s thus consumed on the ground. \nThey are thus at once manured and strengthened in the sta- \nple. \n\n" On dry loams, the best practice is a medium between the \nold and the new ; and the crop is divided between the sheep- \nand the fbld-yard, by drawing off and leaving a fe\\v ridglelt. \nalternately. \n\n" I\'he vast addition made both to the quantity and the qua- \nlity of the dunghill, by the (onsumption of green clover and \nturnips, powerfully recommends them; and turnips accordingly \narc cultivated for this very purpose, on soils but little adapted \nto their growth as an edible root. "When grown on clayey soils, \nthe wholg crop is still carried to the fold-yard, for the object of \nconverting the haulm into manure. \n\n\'^ So the best mode of consuming clover and rye-grass is II \nIvibture it, especially on tlun dry soils; compared with whicli \n\n\n\nFALLOWING. 33 \n\nthe mode of reserving the entire crop for hay is very unprofita- \nble. \n\n" On lands less fit for pasturing, deep loams and clays, soil- \ning is resorted to. A considerable portion of the grass is cut \ngreen for horses and milch cows ; and in some instances, both \nfor rearing and fattening ot cattle. This economical use of the \ngrass in the homestead augments and enriches the dunghill." \n\nROTATION WITHOUT A SUMMER FALLOW. \n\n" The most common rotation on the best dry soils is one of \nfour years. 1. Wheat or oats (assuming the previous crop to \nhave been an artificial grass.) \xe2\x80\x94 2. Turnips. \xe2\x80\x94 3. Wheat, barley, \nor oats. \xe2\x80\x94 4. Clover and rye-grass ; one moiety of the farm be \ning under green crops, and the other under white crops. But \non siliceous sandy soils (flinty sand being the abounding ingre- \ndient) it is necessary to retain the clover and rye-grass division \nfor some years in pasture, unless more manure is applied to such \nland than can be returned jrom its own produce.\'\'^ \n\nROTATIONS WITH A FALLOW. \n\n** On clayey loams the rotations are more varied. On strong \nclays, beans is the best relieving succession crop ; and although \nit cannot be proposed as a perpetual substitute for a summer \nfallow, in alteration with wheat or any other exhausting culmi- \nferous crop, \xe2\x80\x94 yet when drilled, and hand and horse-hoed, beans \nsupersede the necessity of fallowing oftener than once in a \nrotation of six or eight years. Wheat and beans have been \ntaken alternately for a series of years, even as many as eight, \non the best soils ; but the most frequent courses art of four \nand six years. The four years\' course is renewed in this \norder: 1. Fallow; 2. Wheat; 3. Clover; 4. Oats. The six \nyears\' course revolves, with nice adaption to every crop, thus : \n1. Fallow; 2. Wheat; 3. Clover and Rye-grass; 4. Oats; \n5. Beans ; 6. Wheat. Or the six years\' rotation is some- \ntimes varied thus : 1. Fallow; 2. Wheat; 3. Beans; 4. Bar- \nley or Oats ; 5. Clover and Rye-grass ; 6. Oats : but by this \narrangement the land is neither so clean, nor so w ell pulverized, \nas it should be in preparation for clovers. On clayey soils a \nnomplete fallow is considered as the basis of every profitable ro- \ntation crop by the most judicious farmers of Scotland ; and \naccording to their concurring experience, on wet cohesive soils, \nhowever good the course of tillage, no trials, made upon a large \nscale, to postpone a fallow for more than eight years, have hi- \ntherto been successful in that part of the island." \n\nSome of the Papers in the above-mentioned General Report^ \nwhich record this result, allude to the climate as being wjet, \n\nr \n\n\n\nS4 I^ALLOVVING. \n\nand humid for a greater portion of the year than in most parts \nof England ; and in some degree attribute the failure, with \nthem, of the jion-fallowijig system to that cause. But having \nno system to manufacture for universal and perpetual applica- \ntion, without regard to the quality of the land, or the local re- \nsources for manure, \xe2\x80\x94 comprehensive views, a candid indepen- \ndence of theory, and an exact balance of the adventure, and \nreturns under both methods, may have a greater share than \nthe climate in their decision. \n\nIndeed it would be easy to multiply quotations from intelli- \ngent writers on this side the Tweed, the tenor of which agrees \nwith the above, both in the inclination to dispense with fallow- \ning, as far as it can be done with profit, and in the admis- \nsion that on certain lands a periodical fallow conduces to \neventual gain. \n\nVery striking circumstances are connected with the Letters \non Agriculture^ from which we are going to borrow almost the \ncounterpart of the above. First, these Letters are not behind \nthe intelligence of the present day, though written five-and- \ntwenty years ago : for rejecting some of the speculative notions \nwhich were then in fashion, the writer took at once the tfenable \nground to which experimental agriculturists have in general \nreverted. Secondly, they are attributed to the pen of His \nMajesty George the Third ; \xe2\x80\x94 a king who, though placed by \nafflictions beyond the reach of flattery, is still praised and revered \nby his people.* ^ \n\nExtracts relating to Rotations without Fallow. \n\n" The dispute which has lately arisen on the subject of sum- \nmer fallows has made me secretly wish that Mr. Ducket, the \nable cultivator, of Petersham in Surrey, would have communi- \ncated his thoughts not only on that subject, but would have be- \nnefited the public by a full explanation of that course of hus- \nbandry which has rendered his farm at Petersham, which has \nbeen now above nineteen years in his hands, so flourishing, \nthough his three predecessors had failed in it.\'\' \n\n" His course of husbandry seems to be the employing clover, \nturnips^ and rye, as fallow crops, and as intermediate ones be- \ntween wheat, barley, oats, and rye ; changing them according \nto the nature and quality of the land." \xe2\x80\x94 Letter dated 1st Jan. \n1787. \n\n" He would in general reject the practice of falloiving on \nlight soils ; as feeding-crops are better, \xe2\x80\x94 from the cattle, while \n\n* Mr. Young had the honour of givh>g them to the public in his Annals of \n^griciiUue. 7th vol., to whom they were sent with all the exterior marks of an \nordinary correspondent : they were subscribed " Ralph Robinson," and dated \nfrom Windsor. \n\n\n\nFALLOWING. 35 \n\n-consuming the crop, treading the soil, and rendering it more \ncompact and firm, which a light soil requires. . . . Besides, this \nenables the farmer to keep a larger stock of cattle, which increases \nhis quantity of manure." \n\n" Thus his land, although never dormant, is continually re- \nplenished with a variety of manures, and thus unites the system \nof continued pasture with cultivation." \xe2\x80\x94 Letter dated otii Mc(rchf \n1787. \n\nExtract relating to Winter Fallows. \n\nIt is to be premised that the texture of some lands gives them \na middle nature between light and heavy ; or else from local \ncauses- there is no dependence that they can be kept sufficiently \ndry in winter for a feeding-crop. " Many soils may be impro- \nved by winter fallows. This may be practiced by ploughing \nimmediately after the grain crop is off in a dry season ; and by \nbeing well water-furrowed during the winter ; and by proper \ndressings in the spring : but Mr. Ducket does not think this \nmethod equal to a feeding-crop of rye, turnips, or tares." \xe2\x80\x94 Let- "*" \nter dated 5th March^ 1787. ^* . \n\nExtract relating to Summer Fallows. \n\nThe joint effect of this and the preceding passage is the more \nremarkable, because the Editor of the Annals of Agriculture \nappended to the first Letter the Note which is exhibited below.* \'v \nThe note bespeaks the echo of a preconceived opinion : but his \'\'^,^, \nCorrespondent had a mind independent of that system which *i- \n\nwould invert, instead of modifying and augmenting, the " ga- \nthered wisdom" of a hundred generations. This reply is a \npointed correction of the mistake in regard to Mr. Ducket. \n\n" He thinks fallows necessary for strong soils, as the clods \nof the earth cannot be well broken to pieces without being some- \ntime exposed to the air." \xe2\x80\x94 Letter dated 5th March^ 1785. \n\nAs in gardens the land can be kept clean by the hoe, and the \nrenovation by manure is more under the power of the cultiva- \ntor, a winter tallow is in most cases sufficient. \n\nVI. By Irrigation. \xe2\x80\x94 Irrigation is often found to be beneficial \nunder two different kinds of circumstances ; being resorted to \nwith different intentions : \n\n\xe2\x80\xa2 " I have at various times, during tlie last fifteen years, viewfed with groat \nattention the husbandry of the very ingenious Mr, Ducket. I took notes of \nwhat I saw for my private information, but did not publish them, as I thought \nI perceived a disinchnation in that gentleman to have them so brought for- \nward ; and on some points, he expressly desired me not. I am glad to find by \nthis memoir (fpr which the Pubhc is much indebted to the author) that he has \nrelaxed in this particular. I wish much that Mr. Robinson, as he has broken \nthe ice, would proceed, and in particular give his courses of crops; and ex^ \nplain, in particular, his nUer rejection offalloivs," \n\n\n\n36 IRRIGATION. \n\n1. To obtain an alluvial deposit left by the water. In winter, \non land where no crop or seed is lodged, but where annual or \nother plants are to be cultivated in the following season : or in \nautumn, whenever the crop is off the ground ; or at any time \nwhen the soil of a fallow requires to be strengthened, this sub- \nstituted for a more expensive manure may be applied. Also \nmeadows may be floated at the seasons judged proper, accord- \ning to the circumstances ot the land, the quality of the water, \nand the constitution of the grass. The practice of the Fiorin \nSchool (founded by Mr. Richardson,) as reported in the Agri- \ncultural Magazine, N. S. No. 6. is in substance thus : " Some \npar s of the Fiorin to be irrigated in November : others in Feb- \nruary : the floating to be continued at intervals throughout the \nsummer ; the water to be one xveek^ or less^ on the meadow, and \ntxvo weeks off it : but the grass not to be mown till October." \nThe result is not stated, in the most favourable event, this me- \nthod could only be proper for grass which naturally grows on \nbogs, and where it is intended to be husbanded as a winter food. \n\n2. In summer, a light shallow irrigation may be directed over \nland occupied with growing plants, where a long continuance of \ndry weather makes it desirable to draw out such a resource. \nThis is merely watering ; and not irrigating, to obtain an allu- \nvial manure. \n\nThe winter irrigation of meadows is, in many districts, the \neffect ot a local flood, which the farmer cannot prevent nor ma- \nterially control : but the temporary mischief is followed with a \nrich compensation. AH plants which are not aquatic, if they \nare covered over the tops with water, have their growth imme- \ndiately arrested ; and if they thus continue inundated during, \nthe winter months, the majority die down to the root, having \nthe herb completely dissolved, and even the roots of others pe- \nrish : but the vegetable matter of the plants thus decomposed \nadds to the depth and fertility of the soil ; and such plants as \nsurvive to shoot again in spring, derive an advantage from the \ndecayed substance of the others, as well as from the alluvial \nsoil deposited by the water. \n\nSir Humphry Davy\'s, theory on irrigation partly corresponds \nwith the above ; but one good effect which he attributes to the \nflooding of meadows in winter, is quite opposed to the admis- \nsion of temporary injury to plants not aquatic. His words are : \n*\' In very cold seasons it [the inundation] preserves the roots \n\nand leaves of the grass from being affected by frost \n\nWater is of greater specific gravity at 42** of Fahrenheit than \nat 32**, the freezing point ; and hence in a meadow irrigated in \nwinter, tht water immediately in contact with the grass is rarely \nbelow 40\xc2\xb0, a degree of temperature not at all prejudicial to the \nliving organs of plants. [He proceeds to relate the following \nexperiment.] In 1804, in the month of March, I examined the \n\n\n\nIRRIGATION. 37 \n\n\xc2\xab \n\ntemperature of a water meadow near Hungerford, in Berkshire, \nby a vvr^ delicate thermometer. The temperature of the air, \nat seven in the morning, was 29">. The water was frozen above \nthe grass. The temperature of the soil below the water, in \nwhich the roots of the grass were fixed,* was 43\xc2\xb0." \xe2\x80\x94 This in- \nsulated observation is certainly not enough to support the prin- \nciple laid down by the Professor. As the water is reduced in \ndepth, in the course of its subsiding and evaporating, there \nmust happen many occasions on which the grass would lie al- \nternately in shallow water, and alternately in thin ice, partly \ncovered and partly exposed, and ready to dissolve as soon as \nany heat acts upon the moisture. \n\nIt concerns the practical farmer who has meadows which ht \ncan either float, or keep dry, to decide by close persoral exami- \nnation, in what manner gi\'asses not aquatic are affected by lying \nunder water during the frosts and other vicissitudes of v. inter : \nof this the state of the grass at the subsiding of the water in \nsprmg, and the weight of the crop, is the proper criterion.] \n\nThe Professor says in another place : "\xe2\x96\xa0 When land has been \ncovered by water in the winter, or m the beginning of spring, \nthe moisture that has penetrated deep into the soil, and even \nthe subsoil, becomes a source of nourishment to the roots of \nthe plant in summer ; and prevents those bad effects that often \nhappen to lands in their natural state from a long continuance \nof dry weather.":}: The alluvial matters which the water may \nhave diffused through the veins of the land is undoubtedly be- \nneficial : but, were the water which has conveyed them to stag- \nnate in the subsoil, it would be more pernicious to most plants \nthan the droughts of summer. \n\nWe now come to some other communications by this distin- \nguished Chemist ; the substance of which may be given with- \nout protest or comment as principles consistent with experience \n\xe2\x80\x94 although they are placed on an original foundation, which \nenlarges the sphere in which irrigation may be safely applied. \n\n" When the water used in irrigation has flowed over a calca- \nreous bed, it is generally found impregnated with carbonate of \nlime ; and such water tends, in that respect, to ameliorate a soil \nin proportion as any of the modifications of lime and charcoal \nv/ere deficient ; but where these are already in excess, water \ncharged with a limy sediment should be withheld j while wa- \n\n\xe2\x80\xa2 Elements of Agricultural Chemistry, p. 239. \nf " Should the frost set in when the water is on the land, so that some spots \nshould be covered with ice for some days, the spot so covered with ice will \nbe of a darker green, and appear more healthy in the spring than the rest of \nthe field. But when they come to mow the hay, the crop will be considerably \nless than that on the other parts of the field that were not covered with ice." \n0)1 Watering JMeadoivs in Brecknockshire. Report by J\\lr, John Clark to tile \nBoard of Jlgricidture, 1794. \n\n^ Elements of A^icultural Chemistry, p. 238. \n\n\n\n38 APPLYING EARTHS AS MANURES. \n\nter impregated with sand, clay, gypsum, or particles of iron, \nwould be beneficial. \n\n" Common river water generally contains a certain portion of \nthe constituents of vegetables and animal bodies ; and after \nrains this portion is greater than at other times : it is habitual- \nly largest when the source of the stream is in a cultivated \ncountry.* \n\n" In general, those waters which breed the best fish are the \nbest fitted for watering meadows ; but most of the benefits of \nirrigation may be derived from any kind of water \xe2\x80\x94 -provided \nthe soil be not already overcharged with the prevailing ingredi- \nent in the deposit left by the water ; and provided, on the other \nhand, that the matter of the soil and the matter of the depo- \nsit are not pernicious when combined. These are general prin- \nciples : 1. That waters containing ferruginous impregnations \n(particles of iron) tend to fertilize a calcareous soil. 2. Fer- \nruginous waters are injurious on a soil that does not effervesce \nwith acids, which is one of the tests of the presence of lime. \n3. Calcareous waters, which are known by the earthy deposit \nthey afford when boiled, are of most use on siliceous soils, or \nother soils containing no considerable proportion of carbonate \nof lime.f \n\nSupposing the farmer to have a complete command over con- \ntiguous water containing a suitable alluvial deposit, he may \nrender a cultivated level, which requires rest and a cheap ma- \nnure, extremely productive with comparatively little labour, by \nirrigating on the above principles. \n\nVII. By applying\' Eafths as Manures. \xe2\x80\x94 When any decom- \n\' posed mass of stone or earth is laid upon or turned into the \ncultivated clod, with the object \xe2\x80\x94 eitherof furnishing a solvent \nto the remains of animal or vegetable matter which encumber \nthe soil by their slow decay, or of enriching the land with some \nsubstance which is apparently taken up by specific plants as \nFOOD ; then the earthy matter is applied as manure. This is a \ndistinct province from that of merely applying earths to mend \nthe texture of the soils as under I. But sometimes the two \ndesigns will coincide. Closely connected with the theory of \nmanures is the inquiry. What is the true food of plants ? \n\n" The chemistry of the more simple manures, the manures \nwhich act in very small quantities \xe2\x80\x94 such as gypsum, the alka- \nlies (which include potash and soda,) and various saline sub- \n/Stances \xe2\x80\x94 has hitherto been exceedingly obscure. It has been \ngenerally supposed, that these materials act in the vegetable \neconomy in the same manner as stimulants in the animal econ- \nomy, or perhaps in some relations as solvents ; but that in ei- \nther case they merely render the common food more nutritive. \n\n* Elements of Agricultural Chemistry, p. 238, \nt^bid, 239. \n\n\n\nON THE FOOD OF PLANTS. 39 \n\nIt seems, however, a much more probable idea, that they are \nactually a part of the true food of plants, and that they \nsupply that kind of matter to the vegetable Jibre rvhich is analo- \ngous to the bony 7natter in animal structures.\'\'\'\'* The probability \nthat Sir H. Davy has assigned to these substjmces their true \noffice in vegetation, is much heightened by the earthy matters \naftbrded by different plants on analysis. On a similar principle, \nthe benefit of a small proportion of shell marl, in the compost \nfor the pine apple, is accounted for in Abercrombie\'s " Practi- \ncal Gardener."! \n\nThe epidermis of the rattan is stated to contain a sufficient \nquantity of flint, to give light when struck by steel ; and some \nsmall proportion of minutely pulverized flint exists generally in \nthe epidermis of hollow stalked plants, where it is of great use in \nserving as a support, and seems to perform an office in the feeble \nvegetable tribes analagous to that of the fine thin shell by which \nmany insects are defended. \n\nAs a prelude to a survey of the effects of different earths as \nmanures, it may be serviceable to glance at those constituents \nin the kingdom of nature, which appear to be the chief agents \nin vegetation. \n\nBefore the true constitution of Water was known, some phi- \nlosophers and speculative horticulturists had supposed, that all \nthe products of vegetation might be generated from water ; an \nopinion which practical experiments have shown to be falla- \ncious. This ancient error, and the revival of it by several \neminent physiologists in the 17th and 18th centuries,:|: was \nfounded on correct observations, in regard to the following \npoints : \xe2\x80\x94 1. The presence of moisture is necessary to germina- \ntion. 2. Water is the vehicle of various particles of nourish- \nment derived both from the air and from the soil ; ^nd no ma- \nnure can be taken up by the roots of plants unless it is present. \n3. Various vegetables, a greater number than can be easily na- \nmed, have been found to grow vigorously with the roots in con- \ntact with water without earth. \n\nIn the same manner, the existence of air-plants, \xe2\x80\x94 the misin- \nterpretation of various phsenomena observed in experiments on \n\n* Elements of Agricultural Chemistry, p. 19. \n\n\xe2\x96\xa0f Hot-house, Pinery, p. 601. The first edition of tlie " Practical Garden- \ner," was published before tlie Elements of AgriculUiral Chemistry appeared. \n\n+ Van Helinont, Boyle, Bonnet, Duhamel, Tillet, and Lord Karnes, zealously \nendeavoured to establish the theory of water being the only food of plants -, \nand Braconnot quite recently, by experiments with distilled water. Margraf, \nBergman, Kirwan, Hassenfratz, Saussure, San Martiuo, and Davy, have expo- \nsed the fallacies of this theory. Every pound of rain water contains one grain \nof earth, besides other impregnations. Plants raised from pure water will \nvegetate only a certain time, and never perfect their seeds. Bulbous roots, \nwhich are made to grow in water, if not planted in earth every other year, \nrefuse at last to flower, and even to vegetate. \n\n\n\n40 ON THE FOOD OF PLANTS^ \n\nthe atmosphere, and the repeated demonstrations that without \nthe presence ot" ah\', or of oxygen gas, neither the germination \nof seeds can commence, nor the offices of vegetation proceed, \n\xe2\x80\x94 have led many inventors of\' new hypotheses on the growth \nand food of plants, to attribute to the agency of Air greater \neffects than is consistent with the daily evidence that many \nother things are equally indispensable. \n\nSo the productive power of mere Earth has been exagge- \nrated. Jethro TuU, the ingenious author of the system \nof horse-hoeing, and after him Duhamel, having observed \nthe excellent effects produced in tillage by a minute di- \nvision of the soil, and by the pulverization of the broken clod \nby exposure to dew and air, were misled by carrying these \nprinciples too far. Supposing earth to be the only food ot \nplants, they contended, that by finely dividing the soil, any \nnumber of crops might be raised in succession from the same \nland, so as to render periodical fallows unnecessary, Duhamel \nattempted to prove that vegetables of every kind could be raised \nwithout manure : but he lived long enough to alter this opin- \nion ; his subsequent trials led to the mature conclusion, that \nno single material constituted the food of plants. The general \nexperience of farmers had long before convinced unprejudiced \ntheorists of that as a fundamental principle ; and also that ma- \nnures were absolutely consumed in the growth of plants. \n\nThe principles of Sir Humphry Davy are nearly, but not im- \nplicitly adopted in the following recapitulation and synthesis. \n\nWater, and air, and earth (as the chief depository of solid \norganic materials,) all operate in the process of \\\xc2\xabgetation. \nNo one principle affords the pabulum of plants : it is neither \nwater, which may form the basis of their fluids, for it exists \nin all the products of vegetation; nor air, of which they give \nout various forms on distillation, such as oxygen, and azote, \nand inflammable gas ; nor charcoal, which is found on analy- \nsis to be a principal constituent of plants ; nor the particles of \nflint, and of gypsum, at other times of lime, found in the stems \nof most vegetables. In all cases, the ashes of plants contain \nsome of the earths of the soil in which the plant grew ; but \nthe earthy particles never exceed y^ in weight of the vegeta- \nble burnt. The soil is the great laboratory in which the main \npart of the food for common plants, or that which conduces to \ntheir gross bulk, is lodged and prepared. In proportion as \nsome kinds of vegetables are found not to exhaust a soil, \nthey must be supposed to derive organic materials from the air, \nas well as from the rain or other water with which their vessels \nmay come in contact ; further, some contrilmtions to the sub- \nstantial juices of all plants may float among the constituents of \nair. To all kinds of leaves and fruit, the atmosphere may pos- \n\n\n\nON THE FOOD OP PLANTS. 4l \n\niibly be the medium of the subtile and volatile parti- \n\n\n\ncles WHICH constitute FLAVOUR AND AROMATIC ESSENCE \n\n\n\n* \n\n\n\nThe colour of plants, in regard to the constant repetition of \nhabitual tints, may depend greatly on their free communication \nwith light : but the colour of the foliage, flowers, and fruit, is \nalso affected by accidents in the soil and climate. The princi- \nples of vegetable matter which escape from putrefying plants, \nare either soluble in water or aeriform ; in the one state, they \nform the most useful part of manure j in the other, they swim \nin the atmosphere ; in both states, they are capable of being as- \nsimilated by the organs of contiguous vegetables : for plants \ntake up the elements found in thtir composition, either by their \nroots from the soil, or by their leaves from the air. \n\nThe substances found in plants on analysis may be divided \ninto \xe2\x80\x94 1. Those which constitute the hard mattf-r or frame of \nthe plant. 2. Those wbich are eminently, if not soLly, the \nnutritive materials, whether in the form of dry solids, soft \npulp, or juice. 3. Those which serve as condiments, and con- \ntribute to diversify the scent, flavour, colour, and medical \nproperties. \n\nThe first class includes the simple earths, the earthy bases of \ncompound substances, metallic oxides, and the basis of woody \nand vegetable fibre, great part of which is carbon. It has been \nalready mentioned that the eartliy , matter never exceeds one \nfiftieth part in weight of the whole plant, and it is commonly \nmuch less ; lime and flint are found the most frequently ; mag- \nnesia more rarely ; and clay most seldom of all. No other \nmetallic oxides occur than those of iron and manganesum. \xe2\x80\x94 \xe2\x96\xa0 \nCharcoal is a principal constituent in all plants. \n\nThe second class comprehends several substances which are \ncommon to the animal as well as the vegetable kingdom, and \ntherefore may be regarded as directly nutritive to animals ; \nalong with a great number not generally present in vegetables \nto any sensible degree, although abundant in particular plants : \nthese are, farina, or the basis of starch ; gluten, or paste ; gura, \nor mucilage ; gelatine, or the matter of jelly ; (these three are \nnot always distinguishable;) albunen, resembling the white of \nan egg ; sugar ; water ; wax ; resin ; fixed oils ; fungin, a prin- \nciple detected in the cucumber, abundant in mushrooms ; and \nextract an indefinable substance, changing with the plant ana- \nlysed. \n\nThe third class consists of acids, alkalies, and soluble salts ; \n\xe2\x80\x94 of these the most usual is sulphuric acid, combined with sul- \nphate of potassa ; likewise common salt, and phosphate of lime. \nThe following seem to belong to this class, though sometimes \n\n\xe2\x80\xa2 That is, such as are proper to the plant ; for a rank soil may deteriorate \nthe flavour of edible produce by conveying through the roots some remaining \njuices of % foreign substance. \n\nF \n\n\n\n42 CAUSTIC LIME AS A MANURE. \n\nin intimate combination with substances under the first or \nsecond : \xe2\x80\x94 tannin, or the matter tanning leather ; indigo, and the \nvarious colouring matters ; camphor ; the bitter principle ; the \nnarcotic principle, or opiate ; volatile oils. \n\nIn addition to all the elementary parts actually found, some \naroma, or fugitive essence, which would belong to the third \nclass if it could be detained, may go off in a form thinner than \nair, too subtile to be weighed or measured. \n\nThe accumulation in a plant of the first class of things in a \ndue and healthy proportion, may depend principally upon the \nsoil, as a mixture of earth ; of the second, upon the manure ; \nof the third, in a slight degree upon the local climate, but emi- \nnently upon the power natural to the plant for attracting pecu- \nliar particles in the earth and air. \n\nAfter these introductory remarks on the chief agents in ve- \ngetation, it will be more easy to explain the operation of the \ndifferent earths, or species of decomposed stone, which are laid \nupon lands as manure. \n\n1. Lime as a solvent. (Quicklime.) \xe2\x80\x94 Lime, when first \nburnt, has a caustic property, speedily decomposes vegetable \nand animal fibre, and is soluble in water. After burnt lime \nhas been exposed to the atmosphere a determinate time, it be- \ncomes mild, by taking up Ciirbonic acid ; loses its solubility ; \nand becomes chalk, or carbonate of lime. \n\nWhen newly burnt lime is exposed to the air, it soon falls \ninto powder; in this case it is called Slakt-d Lime. The same \neffect is at once produced by pouring water upon it, when it \nheats violently, and the water disappears. \n\nSlaked lime was used by the ancient Romans for manuring \nthe soil in which fruit-trees grew. Nevertheless caustic lime \nis pernicious to vegetation, as far as it comes in contact with a \ngrowing plant. Where acid vegetable mould \xe2\x80\x94 a radical bane \nin some marshes, moors, and peat-lands \xe2\x80\x94 requires correction, \nproceed as under I. 1. \n\nWhen quicklime, i. e. lime either freshly burnt or slaked, is \nmixed with any moist fibrous vegetable matter, there is a strong \naction between the two substances ; and they form a kind of \ncompost, of which a part is usually soluble in ater. Thus \nlime renders matter, which was comparativeh\' inert, nutritive ; \nand as charcoal and ox}^gen abound in vegetable matters, the \nlime is at the same time converted into carbonate of lime.* \nSo burnt lime, in its first effect, decomposes animal matter, \nand seems to accelerate the progress of such matter to a capa- \ncity of affording nutriment for vegetables : gradually^ however, \nthe lime is neutralized by carbonic acid, and converted into a \nsubstance analagous to chalk ; but in this case it more perfectlv \n\n\xe2\x80\xa2 Elements of Agricultural Chemistry, p. 216. \n\n\n\nMILD, LIME AS A MANURE. 43* \n\nVnixes with the other ingredients ot the soil, and is more ]ier- \nvadingly diffused, more finely divided, than mere chalk artifi- \ncially applied. Burnt lime is probably more benelicial to land \ntontaining much woody fibre or animal fibrous matter^ than any \ncalcareous subsiance in its natural state.* Thus is quicklime \nefficacious in iertiiizing peats, and in reducing under tillage soils \nabounding in hard roots. But when animal or vegetable re- \nmains are destitute of fibrous matter, so as not to require a \npowerful solvent, or when their bulk is not in too large a pro- \nportion, or their tendency to putrescency excessive and noxious, \nthe application of quicklime is an unnecessary reduction of their \nstrength ; therefore to cover or mix them with any simple \nearth, or stone pulverized without burning, will be better. \xe2\x80\x94 See \n" 2. Mild Lime:" Lime moistened with sea-water yields \nmore alkali (soda) than when treated with common water ; and \nis said to have been used in some cases with more benefit as \nmanure. f \n\nIt is most important to the Agriculturist to be apprised of the \ndifference in the operation of common limestone, which is of a \npure white colour, and another kind of limestone which has a \nbrown or pale yellow tincture : for a disclosure of the cause of \nthis difference, the public are indebted to Mr. Tennant. It had \nlong been noticed, that a particular species of limestone found \nin the north of England, when applied in its burnt and slaked \nstate to land, in considerable quantities, either occasioned abso- \nlute sterility, or considerably injured the crops for many years. \nMr. Tennant, by a chemical analysis, discovered that this kind \nof limestone differed from the common, by containing magne~ \n\xe2\x96\xa0Stan earth : and from several horticultural experiments, he as- \ncertained that magnesia, applied in large quantities, in its caus\xc2\xab \ntic state, is pernicious to vegetation. Under common circum- \nstances, the lime from the niagnesian quarry is, however, used \nin small doses, upon fertile soils, with good effect ; and it may \nbe applied in greater quantities to soils containing a very large \nproportion of vegetable matter.:): See, fui\'ther, " 3. Magne- \nsia ;" also soaie restraints on the use of quicklime, in th^ \nfourth paragraph of the next article. \n\n2. Mild Lime, powdered unburnt limestone, marles, and \nchalks, have no solvent action upon animal or vegetable re- \nmains : on the contrary, they prevent the too rapid composition \nof substances already dissqlved ; and they have no tendency to \nform solublejl matters. \xc2\xa7 Calcareous matter, in some propor*- \n\n\xe2\x80\xa2 Elements of Agricultural Chcmistiy, p. 21. \n\nt Ibid. p. 232. \n\ni Ibid. p. 21. \n\nII Ibid. p. 216. \n\n\xc2\xa7 That is to say, not in a direct manner : but where there is any mineral or \n\xe2\x96\xa0saline acid in the staple earth or ordinary manure, tlie radical evil in what is \n-called .so?/?\' lajid, a top drosfsing- of litne, (set abcivcj 1. 1.} ^\\-ill nenfralizc tlm \n\n\n\n44 MILD LIME AS A MANURE, \n\ntions, seems to be an essential ingredient in all fertile soils ; ne- \ncessary perhaps to their proper ttxtui^e, or as a constituent iu \nthe organs of plants.* \n\nAlthough lime, when rendered mild by the recovery of the \ncarbonic acid which was expelled in burning the limt- stone, does \nnot undergo any further change in itself by continued exposure \nto the air, yet when saturated with moisture descending in \nshowers or otherwise conveyed to it, it has the property of at- \ntracting an additional quantity, or second dose, of carbonic \nacid : this \xe2\x80\x94 not entering into its constitution, but hanging loose- \nly about it by a transient association \xe2\x80\x94 the mild lime readily \nparts with to vegetables growing near ; at the same time the \nbulk of the mild lime is a little lessened by the action of mois- \nture dissolving part of its crust. Lime in every state has also \nthe property of attracting volatile oils floating in the air, as well \nas fluid oils in contact with it. \n\nThe efficacy of a dressing of mild lime is proportioned to \nthe deficiency of calcareous matter in the natural soil. All \nsoils which do not effervesce with acids, are improved by mild \nlime, and sands more than clays. The rubbish of mortar, on \naccount of the quantity of sand which it contains along with \nthe chalk, is peculiarly fitted to benefit clayey soils. Marie, \nthough the basis of it is mild lime, is to be distinguished from \na pure calcareous dressing, because it usually contains the re- \nmains of some animal matter, with a little clay or peat. \n\nWhen a soil which requires an accession of calcareous mat- \nter, at the same time contains much vegetable manure, which is \nalready soluble by the ordinary agency of moisture and natural \nheat, without any ingredient that calls for quicklime, \xe2\x80\x94 the cal- \ncareous dressing should consist of chalk, marie, or mild lime .; \n\nacid matter. Quicklime is more efficacious tlian mild lime for this purpose ; \nbut simple chulk, also marie, applied in large quantities, will correct the evil. \nThese manures, by neutralizini;\' tlie acids combined with the mould, qualify \nthe vegetable and other soluble substances also present, to be converted by \nthe influence of the atmosphere and of moisture into nutriment for plants. \xe2\x80\x94 . \nAll the experiments yet made render it probable, that the food of plants, as \nit is taken up from the soil, is imbibed by the extremities of the roots only. \nHence, as the extremities of the roots contain no visible opening, we may \nconclude that the food wliich they imbibe must be in a stale of solution first. \nAnd, in fact, the carbonaceous matter, in all active manures, is in such a state of \ncombination as to be soluble in water whenever a beneficial effect is obtained. \nAH the salts which we can suppose to make part of the food of plants, are so- \nluble in water. This is the case also with lime, whether it be pure or in the \nstate of a salt : magnesia, and alumina may be rendered so by carbonic acid \ngas ; and even miiuUe flinty sand may be dissolved in water. We can see, \ntherefore, in general, though we have no precise notions of the veiy combi- \nnations that are immediately imbibed by plants, that all the substances which \nform essential parts of their food 7nay be dissolved in water. Sijstem of Che- \nmisinj, by Thomas Tliomson, M. D. F. R. S. E. Vol. V. p. 376. 3d. edit. Edin. \n1807. \n\n\xe2\x80\xa2 Elements of Agricultural Chemistry, p. 21. Compare with " Practical \nGardener," p. 601. \n\n\n\nUNBURNT LIME AS A MANURE. 45 \n\nand the application of quicklime should be avoided ; as quick- \nlime is disposed to unite with the soluble matter of dead jjlants, \ndestitute of woody fibre, before the latter can have benefited \nthe soil, and thus forms a compound insoluble in water. Quick- \nlime also, while it purifies, diminishes the strength of animal \nmanures ; it should never be applied with these, unless they \nare too rich, or for the purpose of preventing noxious effluvia, \nas in the cases of reducing carrion, or qualifying night-soil, af- \nterwards mentioned : it is calculated to render soft animal ma- \nnures less nutritive, and to make oily matters insoluble.* \n\nQuicklime is also injurious when mixed with any common \ndung, and tends to render the extractive matter insoluble. Fur- \nther, when it unities with oily matters, it produces a soap not \neasily dissolved, like the less tenaceous compound formed by \nmild lime. \n\nLimestones that contain flinty or clayey particles, are not so \ngood as others for burning into lime j but they possess no nox- \nious quality. \n\nBituminous limestones contain a fraction of coally matter, \nnever amounting to one-twentieth. They make good lime : and \nthe coally matter, so far from injuring land, may, under favour- \nable circumstances, be converted into food for plants. \n\nNothing yet has been said in regard to unburnt limestone. \nIn a district where limestone is plentiful, and fuel scarce, a far- \nmer, anxious to leave no local resource neglected, might natu- \nrally fall upon the idea that lime, in an uncalcined state, if re- \nduced to powder, or ground into small calcareous gravel, would \nbe beneficially applied as a manure where mild lime would be \nserviceable, without being aware that the same practice had \nbeen already partially tried. \n\nThe first attempt to convert unburnt limestone into a manure, \nwas made by Lord Kames : no account, however, is known to \nbe extant, from which we can learn how far it succeeded ; and \nthe trial must be supposed to have proved abortive, if made \nupon moss or moorish lands, which, owing to the great quan \ntity of imperfectly decomposed vegetable remains imbedded in \nthem, cannot possibly be benefited by any substaiice possessing \nless activity in destruction than caustic lime. \n\nMany years afterwards a large machine was erected in the \ncounty of Perth, which was furnished by three pounding-instru- \nments of iron from the Carron Foundry, worked by a stream \nof water, for breaking unburnt lime into small rubble. This \nmachine was unfortunately carried away by a flood before \nthe eff"ects of such lime as a manure could be decisively appre- \nciated ; but as far as the intervening time allowed of experi- \n\n\xe2\x80\xa2 Elements of Agricultural Cliemistry, p. 218 \n\n\n\n46 TIME or LAYING ON MANURE. \n\nments, the conclusions were favourable. Much of it had been \nexpended o.) a farm of Colonel Alexander Kobertson. \n\nAs the thewry of the thing, those who are sanguine in recom- \nmendiiig a fartaer trial of it, suppose that unburnt limestone \nmust ue more powerful in its effects than mild lime, which has \ngOi.e through the double process of burning and conversion into \nchalk. Any given quantity of raw limestone, say they, \xe2\x80\x94 a bush- \nel, tor uistance. \xe2\x80\x94 contains twice as much calcareous earth as \nthe same bulk of slaked lime. Further, it is commonly ima- \ngined by persons who have used both kinds, without making\' \nany accurate experiments, that the effects of the raw limestone \nare slow, but more lasting ; of the calcined limestone, more ex- \npeditious, but not so permanent. But they seem to overlook \nthe true grounds of comparison. Limestone, in burning, loses, \nit is true, considerably in weight by the carbonic acid gas which \nis expelled : Lime, in passing from a caustic to a mild state, \nrecovers this gas from the atmosphere ; but it does not regain \nthe qualities of hardness and cohesion ; and differs from what \nit originally was, as powdered chalk from marble, or nearly so, \naccording to the texture of the. fossil burnt. Unburnt lime- \nstone, therefore, has neither the solvent activity of quicklime, \xe2\x80\x94 \xe2\x80\xa2- \nnor the absorbing power of chalk, \xe2\x80\x94 nor the minute division ol \nmild lime mixed with eai\'th, while an impalpable powder. \n\nihie of laying on Lhne. \xe2\x80\x94 Nothing has been said of the \nstages in husbandry at which the application of lime is most \nbeneficially mad^ : because this is quite distinct from an inquiry \ninto the principles on which the good or ill effect of lime on \ndifferent soils can be accounted for. Indeed it depends on con- \nsiderations which the gardener and agriculturist, each alone in \nhis own province, is qualified to weigh, from an intimate know- \nledge of their respective lands, and by the professional expe- \nrience gained in raising the intended crops. Nevertheless, in \nthe valuable collection of Papers which conveys the gathered \nwisdom of the school of Scottish agriculture, some information \noccurs on this subject, which it may be useful to disseminate, \nas marking the general lines of a successful practice. \n\n" Li the best cultivated counties, lime is now most generally \nlaid on finely pulverized land, while under a fallow, or imme- \ndiately after being sown with turnips. In the latter case, the \nlime is uniformlv mild ; in the former, quicklime, as pernicious \nto vegetation, may be beneficial in destroying weeds. Sometimes \nmild lime is applied in the spring to land, and harrowed in with \ngr\'.ss-seeds, instead of being covered with the plough; and under \nthis management, a minute quantity has produced a striking and \npermanent improvement in some of the hiil pastures of the south- \neastern counties. Its effects are yet perspicuous, after the lapse \nof nearly half a century. In some places, lime is spread on grass \n\n\n\nMAGNESIA. PHOSPUATE OP LIME. 4T \n\nland, a year or more before it is brought under the plough ; by \nwhich the pasture in the first instance, and the cultivated crops \nsubsequently, are found to be greatly benefited. But in v^hat- \never manner this powerful stimulant is applied, the soil is never \nexhausted afterwards by a cuccession of grain-bearing crops, a \njustly exploded practice, which has reduced some naturally fer- \ntile tracts to a state of almost irremediable sterility."* \n\n3. Magnesia in a caustic state (burnt magnesian stone) is \npernicious to vegetation: mild magnesia is in no respect hurt-- \nful, provided there is a deficiency of calcareous matter in the \nsoil. Caustic magnesia, applied to lands charged highly with \nrich nianure, in a proportion not exceeding one-hfth of the ani- \nmal or vegetable remains, is speedily rendered mild by the car- \nbonic acid with which it is supplied, as the nianure decomposes : \nbut it should never be thrown on land where a portion of quick- \nlime already occupies the surface; because, while the quicklime \nis becoming mild by its readier attraction for carbonic acid, the \nmagnesia retains its caustic property, and acts as a poison to \nmost plants. Caustic magnesia will destroy woody fibre the \nsame as quicklime; and in conabination with strong peat, assists \nin forming a manure. If the peat equal one-fourth of the \nweight of the soil, and the magnesia do not exceed j^jth, the \nproportion may be considered as safe. Where lands have been \ninjured by too large a quantity of magnesian lime, peat will be \nan efficient remedy. See also above, 1. Lime as a Solvent, \nMagnesian limestones are usually coloured brown, blue, or \npale yellow : they are found in the counties of Somerset, Lei- \ncester, Derby, Salop, Durham, Northumberland, and York : \nthey are abundant in many parts of Ireland. f \n\n4. Phosphate of Lime. \xe2\x80\x94 This is a compound of phosphoric \nacid and lime, one proportion of each ; it is insoluble in pure \nwater, but soluble in water containing any acid matter. It \nforms the greatest part of calcined bones. It exists in most \nexcrementitious substances ; and is found both in the straw and \ngrain of wheat, barley, oats, and rye ; and likewise in beans, \npeas, and tares. In some places in these islands, it exists in a \nnative state, but in very small quantities ; it is generally con- \nveyed to the land by the medium of other manure; and is pro- \nbably necessary to corn crops, and other white crops.:[: In soft \npeats, or other lands which contain an excess of vegetable mat- \nter, phosphate of lime is one of the most serviceable manures. \nSee IX. 6. : \n\n5. Gypsum, Selenite, or Sulphate of Lime, is found na- \ntive at Shotover Hill, Oxfordshire ; and abounds in many other \nparts of England. Natural gypsum commonly consists of wa- \n\n* Tteneral Report of the Agriculture of Scotland, &c. \nf Elements of Agricultural Chemlstrj\', pp. 220, 221. \nT Ibid. p. 228. \n\n\n\n4S GYPSUM AS A MANURE. \n\nter, sulphuric acid and lime ; 22 parts of water, 46 of sulphuric \nacid, and 32 of lime. Wh.-n the water is expelled by heat, the \nother constituents keep their proportion unaltered. As a ma- \nnure, it is the subject of much difference of opinion. It may \nunravel some perplexities, and conduce to a fair estimate, it we \ntreat of it under the four following heads : \n\nI. Theory of its Operation. \xe2\x80\x94 Gypsum meets in few soils any \nthing which can decompose it; and while its elements remain \nfixed, it neither assists the putrefaction of animal remains, nor \nthe decomposition of manure. The ashes of particular sorts \nof peat contain a considerable quantity of gypsum ; some kinds, \na- third part : and such ashes have been applied with good ef- \nfect as a top dressing for cultivated grasses. In correspondence \nwith this, the ashes of sainfoin, clover, and rye-grass, afford \nconsiderable proportions of gypsum : but only a very minute \nquantity of it is found in barley, wheat and the turnip. The \nreason why the artificial mixture of gypsum with soils is not ge- \nnerally effice^ceous, is probably, because most cultivated soils \ncontain sufficient quantities of it for the use of the grasses, and \nan excess of it above what other crops absorb in their growth. \nGypsum is contained in stable dung, and in the dung of all cat- \ntle fed on grass ; and it is not taken up in corn crops, or crops \nof pulse, and in very small quantities in turnip crops. \n\nIt is possible that lands which have ceased to bear good crops \nai cultivated grass, maybe restored by a dressing of gypsum.* \nAs to a general standard for the application of gypsum, those \nplants seem most benefited by its application which always af- \nford it on analysis : such as lucerne, clover, and most of the \nartiffcial grasses : But where the soil already contains a sufficient \nquantity of this substance for the use of the grasses, its appli- \ncation even on pasture cannot be advantageous : for plants re- \nquire only a determinate quantity of manure ; an excess may \nbe detrimental, and cannot be useful. f \n\nIt has lately been asserted, on the authority of a gentleman resi- \ndent at Pittsburgh, in Pennsylvania, that gypsum is only useful \nas a manure in those parts of the United States that are distant \nfrom the sea not less than eighty miles. On the hypothesis that \nsea-air destroys the fertilizing principle in gvpsum, Mr. R. \nBake^^^ell, a correspondent of the Monthly Magazine,:}: pro- \nceeds to account for its failure as a manure in so many parts of \nEngland. It is enough to dispel this opinion to name the county \nof Kent, as the place where it has most fully succeeded. \n\nSir H. Davy in directing our attention to the constituents of \nthis manure, the composition of the soil, and the nature of the \nplant, has contributed material aids for judging when to apply \n\n\xe2\x80\xa2 Elements of Agricultural Chemisty, p. 224. \n\nt Ibid, 19 \n\nt For October, 1815. \n\n\n\nGYPStJM AS A MANURE. 49 \n\nk :\'\xe2\x80\x94 But perhaps he has not adverted sufficiently to the inimita- \nble chemistry of Nature, by which she may disengage the ele- \nments of gypsum when buried in a suitable soil, and enable par- \nticular plants to extract them in a simpler form. It therefore \nbecomes important to recollect, that the sulphuric acid^ which \nlodges in gypsum in a solid state, can be resolved into \xe2\x80\x94 sulphur\' \noils acid gas^ about 40 parts ; and oxygen, 60 parts ; and that \nwhen the water suspended with the two gases is dissipated, thfe \nproportions will be nearly, \n\nCondensible into sulphur ----- 16 parts. \n\nOxygen ___.._ 54 \n\nWater ------...-.20 \n\n100 \n\nNow, instead of confining the possible benefit to such plants as \nafford gypsum in an unaltered state, may we not conclude that a \nlarge number of vegetables, constituted to reject the calcareous \nbase altogether, may appropriate some modification of the other \nelements ? " The saline compounds (as professor Davy in \nanother place notices) contained in plants, or afforded by their \nashes, are very numerous. The sidphuric acid^ combined with \npotassa, or sulphate of potassa, is one of the most usual. Com- \npounds of the nitric, muriatic, sidphuric^ and phosphoric acids, \nexist in the sap of most plants." In analogy with some late ex- \nperiments of DeSaussure,we may further suppose that sulphuric \nacid, diluted with water by the chemistry of Nature, may be \ninstrumental in converting the starch of plants into sugar. " As \nstarch boiled in water with sulphuric acid, and thereby changed \ninto sugar, increases in weight without uniting with any sul- \nphuric acid or gas, or without forming any gas, we are under the \nnecessity of ascribing the change solely to the fixation of water. \nHence we must conclude, that starch-sugar is nothing else than a \ncombination of starch with water in a solid state. The sul- \nphuric acid is neither decomposed, nor united to the starch as \na constituent ; nevertheless it is likewise found that long boiling \nin pure water does not convert the starch into sugar."* This \nfact opens a large field for rational speculation qn the physiology \nof vegetables ; as it renders it possible that some of the mineral \nacids in the sap of plants, after acting chemically^ on the juices \nconcocted into pulp, may be thrown out unchanged : they may al- \nter the flavour without entering into the essence of the fruit. \n\nAnother step in the process of conversion brings us to pure \nsulphur. Some plants yield this on analysis. Seeds, sown by \nway of experiment on nothing but this mineral, have produced \n\n* See a Translation of the original Paper in Jminls of Philosophy for De- \ncember 1815. (No. XXXVI. pp. 425, 426.) \n\nG \n\n\n\n50 GYPSUM AS A MANURE. \n\nhealthy plants ; and many soils, which nature has inr.pregnatetl. \nwith sulphur, are highly fertile. \n\nThe peats or loams on which gypsum has been most success- \nful, niav contain vegetable acids calculated to decompose it. It \nis true that the means by which human art can at present sepa- \nrate its elements are very limited. It is decomposed, 1. by the \noxalic acid ; 2. by carbonates of potash ; 3. by carbonate of stron- \ntium ; 4. by muriates of barytes. The second and third solvents \nare only mentioned to be dismissed, as unlikely to be of .ny use \nin agriculture : the carbonate of lime generated by the second, \nbeing less soluble in water than the sulphate ; and chalk, when \nwanted, can be had at a cheaper rate. The third, carbonate of \nstrontian, is a newly-discovered earth, of rare occurrence. As \nto the compound produced by the fourth, sulphate of barytes is \nperfectly insoluble in water : and it is a reasonable suspicion th\'at \nit would be pernicious to vegetable life. \n\nTo recur to oxalic acid, the first-mentioned solvent. This \nis naturally present in wood-sorrel, and is procured artificially \nby the action of nitric acid upon sugar, and several other vege- \ntable substances. Peat-moss, in an unreclaimed state, usually \nabounds with oxalic acid : hence there is a mutual action be- \ntween that sort of peat and gypsum. Perhaps such a compound \nmight be cheaply imitated, by mixing vegetable mould and wood- \nashes, urine and gypsum ; or short muck, old cow-dung, sea- \nWi-ed, and gvpsum, \xe2\x80\x94 substituting, where sea-weed cannot be \noonv.ned, soap-lye ; or bleacher\'s lees ; or salterns refuse, vege- \nc: I :\' ashes, and water. \n\nIt may be worth\' while also to try, whether in those cases \nvhcre quicklime would form an insoluble compound, or dimin- \nish the nutritive richness of a compost, gypsum may not be a \napital ingredient ; for instance, with some of the following sub- \nstances t oiiif vrtitters ; \xe2\x80\x94 animaLncids; \xe2\x80\x94 all artitnahrtamtres^ par- \nticularlv such ms contain allnoffen, (one element in the white of \neg}j;s is sulphur;) \xe2\x80\x94 the common dung- of cattle. \n\nFurtliur, as mild lime and gypsum seem to be as unlike each \nother as two substances with the same base can well be, it may \nbe of practical benefit to compare their effects in various com- \nposts of the same strength. \n\nTo clone this theoretical part, sulphuric acid has a great at- \ntraction for water, and may be useful in a soil in summer. Where \nthe sulphur cannot be decomposed, it may diminish the cold- \n.ness ot soii\'.e lands. Gypsum may be offensive to delicate aphides \nby the same impregnation; and it may kill some hardy insects \nby setting into a hard crust upon them. \n\nIn addition to the common case of land being already satura- \nted with gypsum or lime, are there any descriptions of soil on \nwhich decomposed gypsum might have a liad effect? 1. Would \nit not deteriorate a soil containing particles of iron ? This may \n\n\n\nGYPSUM AS A MANUllE. 51 \n\nbe put as a caution ; for sulphate of iron is pernicious to vege- \ntation ; but as lime is the antidote to that vice in a soil, decom- \nposed gypsum seems, even in this case, to contain its own re- \nmedy, unless the proportion of lime be thought too low. 2* \nMight not the sulphuric acid hurt the texture of a soil almost \nlivhoUy composed of pure clay ? Sulphate of alumina is not \n. baneful to plants as a salt, though, as a mineral earthy compound, \nit is not the most tractable under tillage : but here again lime is \npi\'esent, to prevent its formation, or to dissolve it. \n\nII. Experience of it abroad. \xe2\x80\x94 It is about half a century since \ngypsum was discovered to have in Pennsylvania almost a \nmagical influence on the growth of red clover; and it is there \nheld in rising estimation. The Pennsylvanian farmers seem to \nhave derived from Europe the first suggestions for applying this \nmanure to artificial grasses. M. Gilbert, from whom a quota- \ntion is given in Sect, iv., states the practice to have long pre- \nvailed in France with signal success. In Germany, Mr. Mayer, \na clergyman, discovered the use of gypsum as a manure about \nthe year 1768 ; and in Voghtland, in Saxony, gypsum-earth is \nsaid to have converted several barren tracts into fruitful fields. \nThe agriculture of Switzerland has also reaped much benefit \nfrom the same resource. \n\nIII. Experience of it in this Island. \xe2\x80\x94 Perhaps it has not yet \nreceived a fair trial here ; but as far as experiments in different \ncounties of England and Scotland are reported, the mass of evi- \ndence is against it. \n\n[As the FinsT ExPEniMEUT of Arthur Young relates to a particular point in \nihe " Method of Pi\'cparing and Applying it," it is given under that head.] \n\n\n\nSECOND EXPERIMENT by the EDITOR of ANN. AGRIC. \n^Marked five square Rods of Clover on a good Turnip Loam -with a gravelly bot\' \ntoiii, luorth lOs. an acre, in JYIcirch, 1791. \n"No. 1. Sprinkled with one quart of gypsum. \n\n2. Two quaris. \n\n3. Three. \n\n4. Four. \n\n5. Five quarts of wood a.shes. \n\n\'* Nos. 1 and 2 were equal, and ratlier superionr to any of tlie rest. No. 5. \nwas the worst. The clover manured (compared with tlie adjoining land that \nhad no manure) was not only considerably higher, but thicker, of a deeper and \nmore luxuriant colour, and of a bi\'oader leaf. \n\n" One quart to a rod, is five bushels to an acre. I am confident that neither \n\xe2\x80\xa2iuch a quantity of night-soil, pig-dung, peat-ashes, nor any other manure with \nwhich I am acquainted would liave had an equal effect. The result of this ex- \nperiment is therefore quite contrary to that of last year.* A. Y." \n\n\n\nEXPERIMENT by JOHN ALLEN, Esq. on four square Rods, First Year\'s \n\nclean Clover. \nNos. 1 and 4. No manure. \nNo. 2. Four quarts of sifted cinder-ash which had never been exposed tp \n\nthe atmosphei\'e. \nNo. 3. One quart of gypsum. \n\n* Annals of Agriculture, Vol. XVI. p. 184. \' \n\n\n\n\'52 GYPSUM AS A MANURE. \n\nWhen the clover was in full head, all^being mown, the produce of Nos. 1 \nand 4. averaged 38 /6s. 6 oz. each. , \n\nNo. 2. weighed 50 lbs. \nNo. 3. 54 i lbs.*- \n\n\n\nAnother gentleman, Mr. R. Procter Anderdon, of Henlade, \nSomerset, atter detailing some trials, says, \xe2\x80\x94 " Hence I conclude, \ns\'s tar as my experiments go, that on many plants, or on many \nsoils, gypsum powder will have no effect ; but that it has an ef- \nfect on old clover, on a loamy soil ; and that a greater effect may \nbe reasonably expected from it, when applied to younger plants of \nthe same sort."f \n\nFrom a subsequent Letter of the same Correspondent, it \nseems greatly to promote the growth of Chicory, and to be de- \nstructive to the slug. \n\nA farmer, near Epping, in ITQl, found it greatly to increase \nthe returns from a sowing of oats. \n\nThe extensive experiments made by a Kentish farmer, in the \nyears 1792, 1793, and 1794, are reported in the Bath Papers., \nvol. VIII. The first states generally that they were chiefly up- \non " light loams and poor calcareous soils, especially of the \nchalky kind.\'\' It is therefore very important that the following \nobservation, which occurs in detailing a particular experiment, \nshould have a conspicuous and prominent place. " A light \nloamy earth to the depth of three feet on chalk, produced much \nbetter crops, than a shallow surface on chalk, both having been \nmanured with gypsum." The plants were chieHy sainfoin, cow- \ngrass, and Dutch clover ; and repeated trials were attended with \nfavourable results. / \n\nTo these might be opposed many instances of the failure of \ngypsum as a manure, in various parts of England, even when \napplied to grass-lands : but the failures uniformly consist, not \nin any pernicious effect, but in the want of any superiouj;, re- \nturns, compared with unmanured lands of the same quality. \n\nWhether it is that in North Britain the farmers find it more \nprofitable to pare off peat, and use it as a compost for lands un- \nder tillage, than to attempt the reclaiming of entire beds of \nsoft peat by immediate cultivation,\xe2\x80\x94 or whether they have \ncheaper top-dressings, \xe2\x80\x94 the sum\' of their experience in regard \nto gypsum, is expressed in the following sweeping conclusion : \n" Gypsum has not hitherto been attended with any success in \nScotland.":]: As to grass-lands not abounding in vegetable re- \nmains, what has been stated under head i. makes it less surpri- \nsing that a dry powder, so hard to decompose, should not have \nproduced any effect corresponding to its reputation in Ame- \nrica. \n\n\xe2\x80\xa2 Annals of Agriculture, vol. XVI. 303. \nt Ibid. vol. XVII. p. 297. . \xe2\x80\xa2 \n\nk General Report of the Agricultural State on Scotland, vol. II. p. 537, \n\n\n\nGYPSUM AS A MANURE. 53 \n\nIV. Method of preparing and applying it. \xe2\x80\x94 Even those wri- \nters who maintain that there is nothing like gypsum, pointedly \ndiffer in their instructions for preparing and applying it. One \nin the opposite hemisphere says : " The spring oi the year has \nbeen esteemed the best season for sowing it; but Ihave sown \nit in March, April, May, June, July, August ; and 1 know no \ndifference in its effect. You will observe, it is only a top ma- \nnure, therefore must be sown on a sward of grass : it is parti- \ncularly good for white and red clover. It may be broken by- \nhand, and afterwards sifted ; but we stamp it, and afterwards \npass it through our mill-stones : it must not be calcined"* \n\n" Six bushels to the acre I use, and it is preferable \n\nto fifty loads of the best dung. This you must think extrava-* \ngant ; it is so, and yet true."f \n\nM. Gilbert, author of a Treatise on Artificial Grasses^ pub- \nlished in France,:]: says, that " it produces the same effect whe- \nther IT IS CALCINED OR ROUGH, if it is but powdercd ; that \nsix bushels, Paris measure, manure very well an acre for a year; \nand that half that quantity does for the two following years. \nThe only thing to be attended to, is, not to sprinkle this manure \nbefore the seeds which are mixed in the herbage are near ripe : \nif sowed sooner, it makes the trefoil grow so fast as to smother \n\nthe grass with which it is mixed It only produces^ \n\nbeneficial effects when sowed after or before rain ; sowed on dry- \nland which continues such, its effects are nothing." \n\nAs to CALCINING : It is not likely to make any difference, be- \ncause the sulphuric acid in gypsum cannot be expelled by the \nmost violent heat of the furnace ; and an experiment of Arthur \nYoung\xc2\xa7 countenances the assertion, that the effects of gypsum \nare the same, whether calcined or rough. It is thus stated ; \n\n" Spots -were staked out on an upland meatlo-,a of clover. \n\nNo^l. A perch iincalcined. The grass weighed, green, 112 lbs, \nNo. 2. Calcined. 114 lbs. \nNo. 3. No manure. 113 lbs." \n\nThe produce is vincommonly great ; but the equal success ol \nthe unmanured piece makes this experiment a comparative \nfailure. \n\nThe American farmers employ it upon netu ground., and \nstrew it upon the surface. In reclaiming a peat not already dis- \nposed to form sulphate of lime, it may qualify an excess oi^oft \nvegetable matter very beneficially. It does not follow, however, \nthat on lands differently circumstanced, particularly upland \n\n\xe2\x80\xa2 Extract of a Letter from Philadelphia, dated Sept. 16, 178S, A/inals of \nAgriculture, vol. XV. p. 109, \nt Ibid. June 1, 1790, p. 110. \n\nt Reviewed in J/inals of Jlgricnlturp, vol. XV. p. 444. \n^ Annals ^f Agriculture, vol. XIV, p. 319. \n\n\n\n54 ON CLAY-BURNINCJ. \n\npastures, which aecm to be worn out, the same mode of appli- \ncation ought to be adhered to ; and it a restorative is sought in \ngypsum, the history both of its successes and its faikires, would \nrecommend a compost containing peat, or some imitation of it. \nThis will be a fair test of what it can effect. \n\n6. Burnt Clay. \xe2\x80\x94 Of late, very flattering reports have been \ncirculated of the practice of burning clay into ashes, for a top \ndressing. It is not a recent invention : for very pai-ticular in- \nstructions for doing it are given in a small Treatise, published \nnear a century ago.* Revived lately in Scotland, the process, \ndescribed in a letter by Mr. Craig, has excited much attention, \nand induced many spirited agriculturists, in various parts of the \nisland, to adopt it on a large scale. The expectations from it \nare sanguine ; although the experience had of it is not yet ex- \ntensive enough to form a ground of recommending it for gene- \nral application, it is called " Burning Clay for Manure : yet, as \nthe torrefied powder is not valued for any vegetable ashes suppo- \nsed to be contained in it, as in the common practice of paring and \nburning, but is simply to operate as burnt earth, it were more \ncorrect to modify the term to " Burning Clay to improve the Tex- \nture of the Soil." This is not a verbal distinction, but a practical \ndifference. If attention to it should much contract the field for the \noperation, it may prevent many disappointments. Thus, suppose \nthe agriculturist is induced, from his system of farming, to cul- \ntivate turnips on a clayey soil, not well adapted to their gi-owth, \nit is plain that the ashes of burnt clay, copiously distributed over \nthe surface, would immediately consult the ^habits of the plant, \nby dividing a tenacious, and rendering drier a humid soil ; and \nthus, without supposing the burnt clay to act as a manure, the \ntexture of the staple would receive a permanent improvement. \nOn the other hand, if on a soil not rich in the common basis of ve- \ngetables, and which is to be planted with any of the exhausting \nculmiferous crops, or other crops dependent on a generous soil, \nthe panacea of mere burnt earth is resorted to, as a substitute \nfor the long tried proportions of consumable manure, the result \nof such an ill-timed application of fire must be disappointment. \n\nIndeed the operation of burning clay for ashes is so tedious \nand expensive, that even where the circumstances of the land \ndemand such an improvement, the outlay would overwhelm the \nfarmer \xe2\x80\x94 unless he intermit the practice during those stages of \nrotation in which he can raise beans, and other crops fit for clay \n\n* Tlie Practical Farmer ; or, the Hertfordshire Jliisbandman. See a Let Icr in tlie \nFarmer\'s Magazine, No. LXllI. with ilie si.tynivtiire " J.-G. F." It is also men- \ntioned in The Coitntrii Gentletna/i\'ii Conipanioii, b_v Stejjhen Switzer, Gardener. \n(London, 8vo. 1732) \'I\'liis latter work slates, lliat the Earl of Halifax was \nthe inventor of this resource : and it gives several letters, written in 1730 \nand 1731, attesting- its success in several ]5arts of Kiii^-land; with accounts from \nScotland that it had answered better than lime or dung !\xe2\x80\x94 but was found too \nexpensive. \n\n\n\nON CLAY-BUllNING. 55 \n\noils, by easier modes of tillage. If, however, he is satisfied \nto prepare land, by this practice, for the green crop, or other \nstage of a rotation which most requires it, and is attentive at \nother times to keep up the vegetable strength of the staple by \nsoluble manures adapted to repair the exhaustion of preceding- \nharvests, and to meet the appetite of the expected crop, the \ntexture of the soil will be gradually improved, while the dan- \nger of relying upon burnt earth as a manure will be avoided. \nIf the surface burnt is a peat, or moss, or contains the roots or \nother remains of plants, the ashes may be truly a manure ; but \nthen the principle and its application are assimilated to the \npractice of paring and burning tuif, and the useful commerce \nin peat ashes ; neither of which is a novelty. So a marl, fraught \nwith animal remains, is decidedly a manure. \n\nThe clay may. be either burnt in heaps, or in kilns. For this \npurpose, it is dug or pared off in shallow spits, ab-.ut four in- \nches thick. Two layers of these are commonly taken. Whe- \nther any part of the subsoil should or should not be also dug \nup, depends upon its composition. See above, Sect. IV. It \naccelerates the process of ignition to set the spitfuls first to dry, \neither separately or in open piles. The kiln may be fired with \nfurze, wood, cinders, coal, or any combustible refuse. As to \nthe quantity of ashes to be applied, the Hertfordshire Husband- \nman says, \xe2\x80\x94 " About forty bushels, sown on an acre by the hand, \nout of the seed-cot, and harrowed in with barley and grass \nseeds, does vast service." The Scottish agriculturists assign \nfrom twenty to twenty-five cubic yards per acre, as a dressing \nfor turnips. \n\nWhen kilns are used, limestone may be burnt with the clay. \n\nIf this practice be combined with that of burning with lime \ninstead of fire, the expense will be lessened, and a manure of \nbetter composition obtained. It may be acceptable to describe \na good method of doing both together.* \n\nPare off the sods, or turf, and surface clay, with the skim- \ncoulter plough, or other convenient instrument, and dry the \nparings ready for burning. Get quicklime fresh from the kiln \nin the following proportion : having marked out a base for the \npile, for every square superficial yard, three Winchester bush- \nels of lime ; or for a mound seven yards in length, three yards \n:md a half in breadth, 72 bushels. In building, begin with a \nlayer of dry parings, six inches in height ; on which spread half \nthe lime intended to be used, about five inches thick, mixing sods \nwith it; then a covering of eight inches of sods ; on this the other \nhalf of the lime is spread, and covered a foot thick ; the height \nof the mound at this stage being about ayard. Mr. Curwen deems \nit better to suffer it to ignite of itself, than to effect the combustion \n\n* The following- is derived from the Letter of Mr. Curwen, of Workington- \nHall, to Mr. Dempster, of Diinichen, publi.shed, by permission, in the Farmer\'^ \nMagazinp, No. LXJV. p. 411. \n\n\n\n5(5 AllNERAL SUBSTANCES. \n\nby applying water. In twenty-four hours it will take fire. When \nthe fire is fairly kindled, fresh sods must be applied. Mr. C. \nrecommends obtaining a suflicient quantity of ashes, before any \nclay is put upon the mounds. The lire naturally rises to the \ntop. It takes less time in piling, and effects more work, to draw \ndown the ashes from the top, and not carry the mound higher \nthan six feet. The clay if not sufficiently burnt is lumpy, and \nunlractable under tillage : on the other hand, Mr. C. regards \ncalcined ashes as of no value ; but they ought certainly to be burnt \nto a powdery state, or until they will fall to powder from a slight \nstroke ; and it does not appear that the calcination of any earth \nlessens its absorbmg power. The finer clav-ashcs arc, the great- \ner is their capacity of absorption from the atmosphere. \n\nSome idea may be formed of the spirit with which Mr. C. \nlias taken up the trial of this system of surface-soil and clay- \nburning, when he says, " I have just completed paring twenty- \nsix acres of clover lea of the second crop, which I intended \nnext year for turnips. The sods were well broken with the \nharrows, which freed them of the greatest part of the mould. \nThe residue was burnt, and has afforded me above a thousand \nsingle-horse carts of ashes. There are twelve mounds with se- \nventy-two Winchester bushels of lime each I have ma- \nnufactured for use this season, two thousand single carts of \nashes." \n\nOn lands thus manured, while turnips and clover have, in the \nmost favourable cases, surpassed expectation, wheat has fallen \nbelow it. At present the balance of experience from the recent \ntrials seems to have this inclination : the advantage of bunnng \nclay alone is questionable, as a measure of general applica- \ntion ; and unless vegetable matter or lime is burnt with it, the \nbenefit will seldom repay the expense. When clay has been \nburnt alone, dung, or other manure containing vegetable nutri- \nment, should be spread with it, especially in preparing land for \nan exhausting crop. \n\nMany discoveries in tillage fall into disrepute by being ap- \nplied without regard to local circumstances, or by being con- \ntinued after a suflicient change has been effected in the original \nconstitution of the soil. Burnt clay can only be what physicians \nwould call a topic:vl remedy. \n\nVlII. Bij introducing Mineral or Saline Elements as Ma- \nnures. \xe2\x80\x94 Mineral substances are more or less contained in \ndecayed animal or vegetable matters. When these sub- \nstances have been extracted in a pure state, by a chemical pro- \ncess, they are in general too expensive and too useful in the arts \nor* in the ordinary affairs of life, to be applied as manures: on \nwhich account the following experiments will serve rather to \nslicw the principle or cause of a fertilizing, or contrary effect, \nfrom the gross matters in which they are found, than for the \npurpose of expending the pure extract on any soil, as in the ex- \n\n\n\nDIFFERENT SALTS COMPARED. 57 \n\njvcriments : on the other hand, it will appear, from some of the \ndetails under this article, vvhy\'an earthy mass, or heap ol reluse \nmatter, containing a particular chemical sui)stance,may he bene- \nficial, \xe2\x80\x94 while that substance in a pure state is pernicious. \n\n1. Common Salt, or Muriaie or Soda. \xe2\x80\x94 The Mineral \nAlkali of Soda is tlie basis oi\' Marine Salt. " When common \nsalt acts as a manure, it is probably l)y enterinjj into the com- \nposition of the plant in the same manner as gypsum, phosphate \nof lime, and the alkalies. It has been proved to have been \nsometimes useful in small quantities. It is likewise oftensiveto \ninsects. Some persons have argued against the employment ot \nit, Ijecause, when used in Inri^e quantities, it either does no \ngood, or r(;nd(;rs the land sterile ; but this is not a cause lor en- \ntirely rejecting it. In Cornwall, the n fuse salt from the large \n\xe2\x96\xa0works of dry-salters \xe2\x80\x94 which, it is to be reme>Ml)ered, contains \nsome of the oil and scales or other parts of the juices and skins \nof fish \xe2\x80\x94 has long been known as an admirable manure. But \nas latent muriate of soda is one of the constituents m almost \nevery kind of animal and vegetable manure, the cultivated lands \nof these islands may be supposed to contain, in general, a sufTi- \ncient quantity for the purposes of vegetation, (not to mention \nthat the surrounding sea must have an effect on the air and soil \nto a considerable distance inland ;) so that a direct supply of it \nto the soil may be found, in most cases, not only useless but in- \njurious.* In the water given to plants which are natives of the \nsea-coast, a minute infusion of common salt would consult the \nnatural circumstances of that description of vegetables : indeed \nthey languish without it.f \n\n2. Comparative Effect or oifferknt Salts. \xe2\x80\x94 Profes- \nsor Davy confirms and illustrates the above and affords a general \nprinciple for the solution of contradictory results under altered \ncircumstances, by an experiment on the effect of different salts \nconveyed in water to the roots of plants. \n\nThe subjects of trial were separate spots in a garden, on \nwhich grass and corn were growing. The soil of the place was \na light sand, \xe2\x80\x94 of which 100 parts contained 60 of flinty sand, \n24 of finely divided earth or chemical elements of earth, and \nj 16 of vegetable matter; and of the whole, less than one part in \n100 was saline matter, principally common salt. The saline \nsubstances tried were super -carhonutc of potassa^ (crystals of \nsoda,) sulphate of potassa^ (vitriolated tartar,) acetate ofpotassa^ \n(foliated earth of tartar,) nitrate of potassa^ (prismatic nitre,) \nand muriate of potansa ; sulphate of soda^ (glauber\'s salt or vi- \ntriol of soda ;) sulphate^ nitrate^ muriate and carbonate of am- \nmonia. The quantities applied were two ounces to each spot \n\n\xe2\x80\xa2 Elements of Agricultural Chemistry, p. 230, \n\nt System of Chenmtry, by Thomas Thoniso/i, M.D. F.U.S.R, vol. V. p. 364. \nod edit. Edlnburgli. \n\nH \n\n\n\n58i SOOT. \xe2\x80\x94 COAL-ASHES. \n\ntwice a week. In all cases wlicrt- Uk quantity equalled j^tfa \npart ot the water, the eflect was injurious ; i)Ui least so in the \ninstances ot the carbonate, sulphate, and muriate ot ammonia. \nWhen the quantities ot the salts were y^tj \'^^ ^^^ solution, the \neffects were different : \xe2\x80\x94 i\'hen, the plants watered with the solu- \ntions ot the sulphates grew just in the same manner as similar* \nplants watered with rain water : Those acted upon by sokuions of \nnitre; acetate, and super-carbonate ot potassa; and muriate ot" \nammonia ; grew rather better ; those treated with the solution of \ncarbonate ot" ammonia grew most luxuriantly of all : The plants \nwatered with the solution of nitrate of ammonia did not grow \nbetter than those watered with rain water ; " probably (says Sir \nH. Daw,) the free acid had a prejudicial effect, and intertered \nwith the result." But if tlu- effect was equal to that ot rain \nwater, there was no proof of a pernicious agency ; the ill effect \nwas mereh\'^ negative, and seems rather to have prescribed a \nslight increase in die quantity dissolved in the water. \n\nIX. Bij Manuring\' with RifuHv Sitbtitanccs not exxrcineti- \ntitioits. \xe2\x80\x94 ileaps ot refuse matter, which contain excrementitious \nsubstances incidentallv, and l)ut in a small proportion, will be \nincluded under this article. \n\n1. SruKKT andRoa.!) Dirt and the Swkepingsof Houses \nmay be all regarded as composite manures. As they are de- \nrived from different sulistances, their constitution varies ; but \nin all cases they refresh and strengthen a soil. Scrapings of \nroads not clayey are i)eneficial without exception : those from \nhigh-roads are enriched in far the greater degree by the drop- \npings of cattle. The promiscuous dung which is gradually in- \ncorijorated with the sludge, is so jjerfectl}\' reduced by exposure \nto the weather, that it takes the appearance of e;!J th. The effects \nof road-drift are in many cases Ijeneficial in a higher degree \nthan the cultivator miglit expect from its known composition : \nbut the greatness of the benefit may ht well accounted for, by \nconsidering that the gravel, or slate, or stone, which is ground \ninto earth l)y the i)assing of carriages along a road, is neccssa- \nrilv virg-in-f(irt/t^ having never been in a state to support vege- \ntation. Fine road-stuff is ix\'tter than dung on pasture land. \n\n2. Soor is a very jjowerful manure ; its great basis is char- \ncoal, in a state of solubility In\' the action of air and water. It \ncontains also salt of ammonia, with a portion of oil. To mix \nsoot witli quicklime is a bad practice ; because much volatile \nalkali is thus disengaged, without any benefit to the land. This \nmanure requires no preparation ; and is well fitted to be used in \na drv state, as a top-dressing (a ])eck to four square poles of \nland) tiirown in with the seed. It is a good improver of cow- \ndung and goose-dung ; either of which alone, and in a fresh \nstate, are of little power. I\'urther, its alkali tends to make oily \nparticles miscible with water. \n\n3. CoAL-AsiiES. \xe2\x80\x94 It appears from an experiment of Mr. \n\n\n\nCoal-water. \xe2\x80\x94 bones. \xe2\x80\x94 hair, &c. 59 \n\nWright, afterwards particularly adverted to, that coal-ashes on \na plot wht;re barley is to be grown has the same efficacy as hog- \ndung ; while it is inferior to the dung of sheep, and something \nbetter than that of horses. \n\n4. Coal-Watkr, or the liquor produced by.; the distillation \nof coal, is said to be a good manure. \n\n5. WooD-AsHES consist principally of the vegetable alkali \n\xe2\x80\xa2united to carbonic acid : and as this alk;ili is found in almost all \nplants, it may be an essential constituent in the organs of the \ngreater part. The vegetable alkali has a strong attraction for \nwater. See the comparative efficacy of wood-ashes with that \nof coal-ashes and the dungs of several kinds of cattle and do- \nmestic fowls, under X. 6. \n\nft. Ca.kbonati: of Ammonia. \xe2\x80\x94 The liquor produced in the \ndistillation of coal at the C^as Esta!)lishments, may be recom- \nmended as a valuable manure on the following accounts. First, \nit principally contains carbonate of ammonia ; (see the experi- \nments by professor Davy already sketched :) secondly, it con- \ntains also a little sulphur. In the proportion of one gallon to \n16 or 18 of water, this liquor may be applied to all green crops \nas a manure, with good effect. When the object is to destroy \ninsects, three gallons only of v/ater should be added to one of \nthe liquor. \n\n7. Coal Tar. \xe2\x80\x94 The tar produced in making carburetted hy^- \ndrogen gas is beneficial as a manure, conveyed in proportion- \nate heaps of earth or marie. One gallon of this tar being mix- \ned with about a wheelbarrow full of mould or fit earthy materi- \nals, will form a compost of great activity. This may be either \nploughed in or used as a top-dressing, as the nature of the land \nand crop may render expedient. \n\n8. Bonks consist of phosphate of lime and decomposable ani- \nmal matter. Bone powder, bone shavings, and bone ashes, are \nserviceable where phosphate of lime is to be supplied to a soil. \nBone ashes ground to powder will impart a reduced share of \nbenefit to aral)le lands, containing much vegetable matter, and \nmay perhaps enable soft peats to produce wheat ; but powdered \nbone, in an uncalcined state, is always to be preferred to bone \nashes, because the oil and other animal matter with which bones \nare richly charged has not been dispelled. \n\n9. Horn is still a more powerful manure than bone, as it con- \ntains a larger quantity of decomposable animal matter :* it is \nvery durable in its effects on a soil. \n\n10. Hair, Feathers, and Woollen Rags, are all analo- \ngous in composition ; they are more nearly allied to horn than \nto bone ; they contain a great quantity of albumen (a substance \nsimilar to white of egg,) gelatine (basis of jelly,) with some, oil.. \nWoollen rags act powerfully for one year. \n\n* RIemcnfs of .AjrriOTlfijral Cliemistry, p. t9S. \n\n\n\n60 liLEACHUll\'S WASTE, &C. \n\n11. }\\EFUSK OF Skin and Le.vTher, accumulating in differ- \nent manufactories \xe2\x80\x94 such as furriers\' clippings, the shavings \xe2\x96\xa0 f the \ncurrier, and the offals of the tan-yard, and the glue-maker \xe2\x80\x94 form ^ \nhighly useful manures ; any one of which, buried in the soil, \noperates for a considerable time.* \n\n12. Bleacher\'s Waste. \xe2\x80\x94 it is usual to cast away the resi- \nduum of the stills as a worthless article : but surely if some \ncompetent person were employed to separate the sulphate of soda \nfrom the sulphate of manganese, the former might be turned to \na good account. The waste solutions of the oxy-muriatic salts \nare also convertible into a valuable manure. See the experi- \nments of Professor Davy, above. Humboldt, about 1810, dis- \ncovered that a weak solution of such preparations, has the pro- \nperty of accelerating and enlarging the growth of vegetables. \nGardeners whose grounds are in the neighbourhood of bleach- \nfields, would do well in availing themselves of all the advanta- \nges their situation affords them for making experiments on this \ninteresting and important subject.f The waste lees, after boil- \ning linen yarn or cloth, may also be used for alkalizing com- \nposts. \n\n13. Soaper\'s Waste has been recommended as a manure, \nunder, the supposition that its efficacy depended upon the differ- \nent saline substances which it contains : but the quantity of these \nis very minute indeed ; its chief ingredients are mild lime and \nquicklime, either of which, when a supply of calcareous materi- \nals, or when a caustic solvent is wanted in a soil, may be had at \na cheaper rate. \n\n14. The Fluid, or Dissolved Parts, of Animal Sub- \nstances, require some preparatory process to fit them for ma- \nnure. The great object is to blend them with the soil in a pro- \nper state of minute division. When these have been applied in \na rank or unreduced state, bad effects have followed. Perhaps \nwhile they retain the combinations of animal matter unchanged^ \nor not ejitirely broken^ they are ill adapted to promote the func- \ntions of vegetable life. Thus tallows and oils, received in a crude \nstate by the roots, may clog the pores of the bloated plant, repel \ndews and aqueous fluids, and obstruct the free communication \nof the kaves with the atmosphere. \n\nOne mode is, to spread the animal fluid thinly on the land un- \nder tillage, and previous to putting iji the seed or plants^ to suf- \nfer the free escape of the volatile particles that will go off by ex- \nhalation. The better mode is to convey animal matter in a com- \npost of earthy or vegetable materials. \n\nBlood is a good manure. The Scum taken from the boilers \nof Sugar-bakers consist principally of bullocks\'\' blood. \n\nWhen sugar-baker\'s waste has been reduced to the finest state \n\n\xe2\x80\xa2 Elements of Agricultural Chemistry, p 199. . \n\nt Chemical Essays, by Samuel Parkes, F. L. S. London, 1815. vol. IV. jO^ \n\n160. \n\n\n\nOIL AND BLUBBER. 61 \n\npossible, it will still be improper for application as a manure^ \nuntil it has been mixed and incorporated with three or four \ntimes its bulk of some earthy substance, which may be enriched \nwith a proportion of vegetable mould or desiccated dung. \n\nGraves also are too rank both for corn and grass, unless con- \nveyed in a compost of earthy materials ; wood ashes may be \nprofitably added, as having a tendency to divide and correct the \nparticles of tallow. \n\nOily substances contain a deal of carbon, and are employ- \ned as manures with great advantage. Animal or vegetable al- \nkali increases their fertilizing power, by converting them into \nsoaps. Quicklime diminishes their, efficacy, tending to make \nthem insoluble. \xe2\x80\x94 Train-oil and Blubber, All the practical \nwriters on the application of train-oil and blubber, and similar \nrefuse, agree that to rectify it, it must be made into a compost \nwith a great body of earth, though they may recommend differ- \nent proportions under the diversified circumstances on which in- \ndividual experience is founded. \n\nThe ingenious Dr. Hunter* advises a compost thus formed ; \nLet \\2lbs. of American potash be dissolved in four gallons of \nwater : mix the solution with twenty bushels of dry mould, and \nfourteen gallons of train-oil. \n\nA Correspondent of the Farmery\'s Magazine^ found that blub- \nber in a crude state, as he applied it in a first essay, destroyed, \ninstead of assisting, vegetation. Twelve years\' experience has \nled him to a most successful method of using it, which he pre- \nsents to the notice of other agriculturists. His plan is to make \nit into a compost in the proportion of nine loads of earth to one \nload of blubber. He first makes a layer of earth two feet thick, \n\xe2\x80\x94 building it a foot higher at the sides, three feet inward, like a \nsolid wall, to form a cavity for the blubber. When the blubber \nhas been laid on a foot in depth, similar layers ai"e repeated to a \nconvenient height till the blubber is expended, leaving three feet \' \nof earth for the top layer : The entire heap is then beat down \nclose at the top and sides to exclude the air. In this state it \nwill ferment, and the earth becomes impregnated with the foul \nair of the blubber. When this fermentation abates, which it \nwill do in about two mouths, the heap is to be turned over from \ntop to bottom. The bottom layer of earth, which thus becomes \nthe cover, will require some addition in thickness, to prevent \nthe escape of air by the second fermentation : When this abates, \nthe compost is again turned over ; and after a third fermenta- \ntion, becomes fit for use. The communicator of this method \nthen adds : " The mixing or applying lime therewith, I have \nfound detrimental, as the lime reduces the blubber, and prevents \nfermentation. I never use this compost until it is nine or twelve \n\n* Georgical Essays. \n\nt No. LXIIL (dated Aug. 7, 1815,) p. 287. \n\n\n\n62 REFUSE FISH. \xe2\x80\x94 CARRION\'. \n\nmonths old. In this state, 1 have applied \xe2\x80\x94 to both grass and. \ntillage land \xe2\x80\x94 about 10 or 15 loads of the compost per acrr, tach \nload weighing two tons ; and have cut from the grass land tliree \ntons of hay per acre, and after-grass in proportion. I have, \nalso used it to tillage crops of Avheat, beans, and potatoes, \non a field of 20 acres, that has not been fallowed for ten years, \nuntil this present summer, but manured annually in the above \nproportion; and from which I have reaped five quarters of wheat \nper acre, \xe2\x80\x94 five quarters of beans, \xe2\x80\x94 and from 1300 to 1500 pecks \nof potatoes, \xe2\x80\x94 with those crops in succession. The land is a \nstrong clay ; and the only difficulty from constant cropping is in \nkeeping it clear from short twitch grass, of which if left in the \nland, the blubber encourages the growth." \n\nPulverized Oil-cake has been used with advantage as a ma- \nnure : it is an antidote to the wire-worm, especially if mixed \n\xe2\x80\xa2with elder or wormwood, when it proves a certain means of de- \n-stroying the worm ; an effect which is explained by reflecting \nthat oil is destructive to most insects. A mill has been invent- \ned for pulverizing oil-cake as a manure, which, with one horse, \nwill, crush five tons per day. \n\n15. Refuse Fish forms an excellent manure, provided the \nquantity be limited, \xe2\x80\x94 and, that sufficient time intervene, before \nthe plants are put in, for the combinations of animal matter to \nbe destroyed. In an instance, recorded by Mr. Young, of too \ngreat a quantity of herrings having been ploughed in for wheat, \nso rank a crop was produced, that it was entirely laid before har- \nvest. In order to prevent a dressing of fish from raising too \nluxuriant a crop, they should be mixed r ith earth, or sand, and \nsea-weed. Their effects are perceptible for several years. \n\n*\xe2\x80\xa2\' The manure produced in the fishing villages from the mix- \nture of all oily and fishy substances, favours bear [barley] and \ngreen crops; but when used much, renders the soil unfit for pro- \nducing oats : hence that soil is called poisoned.\'\'* \n\n16. Carrion is not commonly used as a manure, though \nthere are many cases in which such an applicatioTi might easily \nbe made. Horses, dogs, sheep, deer, and other quadrupeds, \nthat have died accidentally or by disease, are too often suffered \nto lie exposed to the air, or immersed in water, till they are de- \nvoured by birds or beasts of prey, or entirely decomposed : \nmeanwhile, noxious gases are given off to the atmosphere, and \nthe land where they lie is not benefited. By covering a dead \nanimal with six times its bulk of soil, mixed with one part of \nlime, and suffering it to remain for a few months, the decompo- \nsing carcase is made to impregnate the superincumbent mould \n\xe2\x80\xa2with soluble mattei\'s, so as to render the compound an excellent \nmanure; and by .nixing a little quicklime with it at the time of \n\n* Sinclair\'s i^latintical Acccount of Scotland, vol. VII. p. 301. \n\n\n\nMALT DUST. SEA W\'KED. 63 \n\nits removal, the clisagretable effluvia would be in a great mea- \nsure destroyed. Any waste carcase may also be dissolved by \nenclosing it in a heap of vegetable matter in a state of fermenta- \ntion : but it is advisable to urge and sustain the fermentation at \na heat high enough to kill gentles and caterpillars. \n\n17. Rape-Seed Cake, composed of the husks or bran of \nrape-seed, is a restorative manure for arable land. It should be \nvised when fresh, and turned in with the seed. \n\nThere is also a rape-cake formed of the ashes from burnt rape- \nstraw, which contain a deal of alkali. This is a good dressing \nfor turnips. \n\n18. Malt Dust is a manure of great power and vivacity. \nIt answers best as a spring top-dressing. Provide for wheat ten \nquarters per acre; barley, eight; grass-land, four. It excels in \nstimulating a cold soil. \n\n19. Sea weed. \xe2\x80\x94 In some of the maritime counties\' a great \ndeal of sea weed comes in on the shore. This manure is tran - \nsient in its effects, and docs not last for more than a single crop. \nBut for one crop it has been found to be the most productive of \nany.* It is sometimes suffered to ferment before it is used : but \nthis seems wholly unnecessary; for there is no fibrous matter ren- \ndered soluble in the process, while a part of the manure is lost. \nThe best farmers use it as fresh as it can be procured. Where \nit cannot be immediately applied, a good resource to save the \njuices draining from it is to lay it on a flattened heap of- earth \npreparing for compost. \xe2\x80\x94 Sea-weed, as a manure, improves the \ngrowth and taste of esculent herbs. \n\n20. Dry Straw and Spoiled Hay, with every sort of haulm, \nis convertible into manure for all lands. In general, such sub- \nstances are made to ferment before they are employed; " though \nit may be doubted (says Sir H. Davy) whether the practice \nshould be indiscriminately adopted. There can be no doubt that \nthe straw of different crops immediately ploughed into the ground \naffords nourishment to plants : but there is an objeciion to this \nmethod, from the difficulty of burying long straw, and from its \nrendering the husbandry foul. When straw is made to ferment, \nit becomes a more manageable manure : but there is likewise a \ngreat loss of nutritive matter. More manure is perhaps sup- \nplied for a single crop : but the land is less improved than it \nwould be, supposing the whole of the vegetable viatter could be \nfinely divided and mixed with the soil. It is usual to carry straw \nthat can be employed for no other purpose to the dunghill to fer- \nment and decompose : but it is worth experiment, whether it may \nnot be more economically applied when chopped small by a proper \nmachine, and kept dry till it is ploughed ih for the use of a crop. \nIn this case, though it would decompose much more slowly^ and \n\n* Sinclair\'s Statistical Account of Scotland, vol. VII. p. 202.,, \nt Elements of Agricultural Chemistry, p. 1&4. \n\n\n\n64 VEGETABLE MOULD. WOODY I\'lBRE, &C. \n\nproduce less ejfftct at Jirstf yet its injincnce xvould be much more \n/asttn^y* \n\nOn this question, and the proposed artifice for preserving the \nwhole quantity of rtluse straw or hay as manure for the soil, \nthe Reader\'s attention is invited to the Strictures and Sugges- \ntions annexed to the article, Management of Manure from \nTHE Homestead. \n\n21. Vegetable Mould, or tree-leaves decomposed, is a \nmanure so nearly fit for universal application, that no other ex- \nception need be made to it than the case of a soil being already \ntoo rich. It is too valuable to be used on common occasions, \nalone. It may be mixed with sand, perfectly rotted dung, ex- \nhausted bark, or other ingredients, according to the wants of \nthe soil. \n\n22. Woody Fibre. \xe2\x80\x94 "Mere woody fibre (says Professor \nDavy) seems to be the only vegetable matter that requires fer- \nmentation, to render it nutritive to plants. \n\n"Tannkrs\' spent Bark is a substance of this kind. Mr. \nYoung, in his Essay on Manures, which gained him the Bed- \nfordian Medal of the Bath Agricultural Society, states that, \n* spent bark seeyns rather to injure than to assist vegetatwn ;\' \nwhich he attributes to the astringent matter that it contains. \nBut, in fact, (remarks the Professor) it is freed from all soluble \nsubstances by the operation of water in the tan-pit. If injurious \nto vegetation, the effect is owing either to its agency upon wa- \nter ; or more probably, to its mechanical structure and effect, \nbeing very absorbent and retentive to moisture, and yet not pene- \ntrable by the roots of plants."! \n\nBy * Tanners spent Bark,\' in the above passage, it is to be \nunderstood only the bark from which the tanning principles has \nbeen extracted in a tanner\'s vat. This substance, when fer- \nmented^ as directed under \xe2\x80\xa2\xe2\x80\xa2* Hot-house," in Abercrombie\'s \n*\' Practical Gardener," is a great auxiliary to vegetation : in \ngeneral, the excitement from it is only safely given through the \nmedium of mould ; but the offsets and cuttings of many plants, \nstruck into the surface of a bark-bed, will vegetate without earth. \nSee " Pinery," and Grape-house." With regard to its applica- \ntion in the open garden, it is not a fit dressing for^ommon beds, \ntill reduced to an earthy state. \n\nInert Peaty Matter is similar, in respect to the absolute \nnecessity of fermenting it before it can be beneficial as a manure. \nIt remains for years exposed to vater and air without under- \ngoing change ; and, in this state, yields little or no nourishment to \nplants. Lord Meadowbank has recommended a mixture of \nfarm-yard dung for the purpose of bringing peats into fermcnta- \n\n\xe2\x80\xa2 Elements of Agricultuial Chemistry, p. 194. \nflbid. \n\n\n\nSHAVINGS OF WOOD.\xe2\x80\x94 I\'EAT ASHES. 65 \n\ntlon ; for this end, clung is well adapted, but any putrescible \nsubstance will serve equally well ; and the more readily any re- \nfuse litter heats, the bettt-r will it answer the purpose. In or- \ndinary cases, one part of dung is sufficient to decompose three, \nand from that to six, parts of peat : green vegetables, mixed \nwith the peat, will accelerate the fermentation. In the height of \nsummer it will take about three months \xe2\x80\x94 and in the season \ncomprehending winter, six months \xe2\x80\x94 to reduce fermented peat \nto the state of vegetable mould, \'len cubic yards per acre may \nbe ploughed in for wheat. \n\nShavings of Wood, anij Saw-oust, will require as much \ndung, or green vegetable refuse, to bring them into fermentation, \nas the worst kinds of peat. \n\nThe FIBRE and grain of avood can be much\' sooner decom- \nposed by the action of caustic lime, than by the process of fer- \nmentation. The young shoots of pruned trees, and similar ve- \ngetal c refuse, may be speedily converted into a manure, by be- \ning laid in a pit, with alternate layers of quick-lime. Mr. Brown, \nof Derby, has been honoured with a medal, from the Society of \nthe Adelphi, for this contrivance, extending the application of \na principle which has been immemorially known, and recently \nmuch adverted to. See above. Lime as a solvent. \n\n23. Ashes of vegetables not woody. \xe2\x80\x94 The conversion \ninto ashes by combustion of vegetable refuse matter, otherwise \neasily reducible into manure by fermentation, may sometimes \nincrease its fertilizing power in one of thfese ways : either by \naugmenting the tendency in the manure to produce carbonic \nacid, under the combined action of charcoal, moisture, and air, \n\xe2\x80\x94 or by the effect of the alkali in relation to some other manure, \nor the texture of the soil,\xe2\x80\x94 or by some ingredient which would \nbe pernicious in combination being expelled in the burning. \nVegetable ashes, applied as a top-dressing, may also contribute \nto the destruction of insects and their larva;. \n\nBurnt Straw is said, by an intelligent practical farmer,* to \nbe a manure that will insure a crop of turnips. The compara- \ntive efficacy of burnt straw is shewn by an experiment of Mr. \nWright, recorded in a subsequent page. \n\nPeat Ashes have a local utility as a top-dressing for culti- \nvated grasses. The peat ashes of Berkshire and Wiltshire, in \nparticular, are sold at a considerable price for manuring artifi- \ncial grass-lands, and are much celebrated for their good effect. \nProfessor Davy, having analysed as well these ashes as the soils \nto which they are successfully applyed, found in the soils \nthemselves no sensible quantity of gypsum;) the ashes, on the \nother hand, consisted in great part of gypsum, with a little iron, \na little common salt, and variable quantities of calcareous, alu- \n\n\xe2\x80\xa2 Jl General View of the JlgncuUurc of the East Hiding of VorkMre, bv H. K. \nStrickland, Esq. \n\nt Elements of Agricultural Chemistry, p. 19. \n\nJ \n\n\n\n66 NIGUT-SOIL. \n\nminous, and siliceous earth, and sulphate of potassa. But such \nis not generally the case with peat ashes : to produce this pre- \nponderating quantity ot gypsuiu, the peat must be charged with \nvitriolic matter, and lie on a substratum of calcareous eartli. \xe2\x80\x94 \nTurl-ashes are used in the Netherlands for manuring clover and \nother grass lands; and force great crops." \n\nX. By Excrementitioiis Substances applied as Manure. \xe2\x80\x94 The \npotency of dung as a manure varies with the animal affording it. \n\n1. Dung ov Sea-bikds.\xe2\x80\x94 One of the most powerful dungs \nis that ot such sea-birds as feed on animal food. The naturally \nsterile plains of Peru are fertilised by guano^ a species of dung \ncollected Irom small islands in the Soudi Sea, frequented by \nsea-birds. It is used over a great extent ot South America, \napplied in very small quantities, and chiefly for crops of maize. \n\nThe dung of sea-birds had not been used in this country as u \nmanure until a trial of it was made in Wales, at the recom- \nmendation of Sir H. Davy ; in which instance it produced a \npowerful but transient effect on grasses. \'I\'hat sagacious and \ncandid experimentalist hence conjectures, that the rains in out- \nclimate materially injure that species of manure, unless where it \nhappens to be deposited in caverns or fissures of rock, out of \nreach of the weather. \n\n2. NiGHT-SoiL, in whatever state used, whether recent ot \nfermented, is a very powerful manure, and capable of supplying \nabundant food to plants. Saw-dust is a good vehicle for it. \nThe disagreeable smell of night-soil may be destroyed by mix- \ning it with quick-lime; and if exposed to the atmosphere in. \nthin layers, strewed over with quick lime, in fine weather, it \nspeedily dries, and is easily pulverized : so prepared, it may be \nused in the same manner as rape-seed. The Chinese mix their \nnight-soil with one third of its weight of a fat marie, make it \ninto cakes, and dry it by exposure to the sun. These cakes, \nwhich are said to have>no disagreeable smell, form an article \not commerce. In the neighbourhood of London, this manure \nis prepared for sale in a concentrated state, so as to be inoffen- \nsive in the carriage, even Avhen conveyed in bulk. The Cona* \npressed Night-soil may be commodiously used as a top-dressing \nlor wheat in the spring of the year, and for all kinds of spring \ncorn, for young clovers, and other green crops ; one hogshead \nwill be sufficient for an acre, when it has been prepared with \ndue attention to the preservation of its fertilizing properties. \nAs an enriching manure, many experiments have established, \ntliat human ordure is to be ranked many degrees before the \ndung of the pigeon, hen, sheep, or swine ; powerful as all these \nare. But its effects are .not so permanent as those of many other \nsubstances. From recent experiments, Mr. Middleton con- \ncludes, that no other manure can compete with it for the first \nyear after its application ; in the second year, the benefits from \nit are very much diminished ; in the third, its effects, nearly, if \n\n\n\nDUNG OF FOWLS. 0< \n\nnot quite, disappear. Much depends on the depth of soil. \nThere can be no doubt that a substance in which the pi\'inciple \nof vegetable nutriment is highly concentered, is in pro|jortion \nwell calculated for speedily restoring or enriching land, and ior \nforcing great crops without detriment, \xe2\x80\x94 supposing the staple to \nbe deep enough for tillage, and to be fidy constituted as to tex- \nture. On the other hand, a shallow dip of mould requires con- \ntributions of new earth, without which forcing manures v.\'ill \nbut exhaust it sooner. \n\nOn the authority of trials which seem to be convincing, \nsome writers have insisted that an inconceivable loss of valua- \nble fluid is incurred by exsiccating night-soil. Though thi\xc2\xa7 \nmay be a good reason for forming this sul)stance into a compost \nwith earth, where it can be consumed on the spot ; yet it is none \nagainst the use of the article in a cgncentrated state, in which \nthe loss, a*? far as the escapirig fluids are not transferred to some \nabsorbent compost, falls upon the preparer ; while the expense \nof carriage, in regard to the solid essential part, is materially \nlessened. \n\n3. Pigeon\'s Dung is next in fertilizing power. When dry, it \nmay be employed as other manures capable of being pulverized. \nOne tenth part of pigeon\'s dung, four parts of sand, and five parts \nof vegetable mould, is a good compost for a cold heavy soil. \n\nThe foUo\'-.ing interesting quotation must recommend pigeon\'s \ndung as a fine ingredient in a compost for melons. " The pro- \nduce of the sub-district of Linjan (in the province of l;;ak) \nis not inferior to that \'of the most fertile spots in Persia, \'i\'his \niub-district is about seventy miles in length and forty in breadth : \nit is irrigated hy canals cut out from the Zeinderood, and covered \nwith villages, which are surroimded with gardens and prodigi- \nous numbers of pigeon-houses. On inquiry I found that these \nbirds are kept principally for the sake of their dung, and that \nthe acknowledged superiority in the flavour of the melons at \nIspahan, is alone to be ascribed to this rich manure. The lar- \ngest of the pigeon-towers will sell for three thousand pounds ; \nand many of them \\ield to the proprit-tors an annual income of \ntwo or three hundred pounds each."* \n\n4. The Dung of Domestic Fowls approaches very nearly \nin quality to pigeon\'s-dung. It is very liable to ferment.f \n\nSir Humphrey Davy here ranks the dung of domestic fowls \nnext to pigeon\'s dung, without dciining what species of fowls \nIS intended, or discriminating between the different kinds of do- \nmestic fowls. It appears from a set of comparative experi- \nments recorded in the Agricultural Magazine, that Hen dung, \n\n\' fieographicaKMcDi\'jiv of the Persian Emfn\'re, hy Jolm Macilnnald Kennirr. \nrolitical Assistant to Sir .lohn Malcolm, in his Mis.4ion to tl^e f;o\\in of Persia, \n4to. London, 1813. p. 110. \n\ni F-Icmonts of A frri cultural Chemistry, p. 204 \n\n\n\n68 KXI\'KRIMENTS WITH MANUUES. \n\nor the dung of the common fowl, is most efficacious ; Duck \nclung is to.be rated second ; while Goose dung was found so in- \nferior that the produce from a spot manured with it was not \nmuch above the average of three patches sown without manure. \nSee the statement at length, under article 6. \n\n5. Rabbit\'s Dunc has been used with great success as a \nmanure ; so much so, that it has been found profitable to keep \nrabbits chiefly for the sake of the dung, and to have the hutches \nconstructed in subservience to the object of accumulating it with- \nout waste. \n\n6. The DuNc; ov Cattle. \xe2\x80\x94 " Of the dung of cattle (says \nSir H. Davy,) that of hard-fed horses appeal\'s to be the strongest. \nThe dung of sheep and deer is thought to be more efficacious \nthan that of oxen. The dung of oxcji is supposed, by many, \nto require a long preparation to fit it for manure. \n\nTo combat the opinion that ox-dung requires a long prepara- \ntion. Sir Humphry then enters upon a course of argument \nagainst the general practice, in regard to fermenting promiscu- \nous dung-heaps. " If the dung of cattle is to be used as a ma- \nnure, like the other species of dung which have been mentioned, \nthere seems no reason why it should be made to ferment except \nin the soil ; or if suffered to ferment, it should be only in a \nslight degree. The grass in the neighbourhood of spots where \nunfermented dung has been dropt, is always coarse and dark \ngreen : some persons have attrilnited this to a noxious quality \nin unfermented dung ; but it seems to be the result rather of aa \nexcess of food furnished to the plants." \n\nThe estimate founded on the experiments adverted to under \narticle 4. above, does not correspond with the order in which \nthe dung of horses and that of s^Jieep are mentioned by Sir H. \nDavy ; and it countenances the objection held in common by \nmany practical men against the use of fresh cow-dung. Nine \ndifferent kinds of manure having been tried on patches of bar- \nley, the result was as follows : \xe2\x80\x94 \n\nHen-dwig Most efficucious. \n\n[hick-dimg Second in power. \n\nSheep-dung Thii-d. \n\nLI . 1 ^ \\ ...Exactly alike. Fomth \n\nIhrse-dmg Fifth. \n\nIVood-ashea Sixtii. \n\n^ , C Seventh. Not much above tlie averaffc of three patches \n\nGoosc-dmi:t..< -.i . & i \n\n^ I sown witliout manure. \n\nCow-dutig Evidently prejudicial. \n\nThe quality of the land is not stated ; but possibly one cause \nof the cow-dung being prejudicial, was the natural coldness of \nthe soil. Moreover, barley is extremely impatient of dung that \nis not well digested and divided. But on warm arid soils, cow- \ndung may be an improving manure, if fermented with other \n\n\n\nEXPERIMENTS WITH MANURES. 6!) \n\ndung, or kept alone till it can be pulverized. In canvas3in[i \nthis point with an eminent liorticulturist, he informed me^ that \nit is his own practice, and that of many gardeners skilled in pre- \nparing choice composts, to keep cow-dung for a period of three \nyears, before they apply it either alone as a manure, or as an in- \ngredient in a composite mould. When used in a fresh state, as a \nmanure, it shoiiTd never be alone, but mixed with any such arti- \ncles as the following, of a warm nature, and easily pulverized : \nthe dung either of the sheep, the hog, the horse, the rabbit, the \npigeon, the hen, the duck, with "some of the animal manures ; or \nwith lime and sand, marie, soot, coal-ashes, the ashes of any \nburnt vegetable, or other substance ; as the soil may want either \nto be strengthened, or to be cooled with as much cow-dung as \ncan I)e applied without its peculiar disadvantages. Properly, \nqualified, it is a good dressing for most shrubs and fruit-trees. \nAs the texture of the soil varies, or as a plant of a different \nnature forms the crop, so the proportion of fertilizing power \nwhich a comparative trial of manures has fixed in one instance \nwill vary in another. Still some manures seem to be universally \ninferior ; while others, though not always standing in the first \nplace, may be relied on for conducing to a profitable return. \nA paper by the Rev. James Willis, President of the Christ\' \nChurch Agricultural Society, records two valuable experiments, \nmade to ascertain the positive effect of different manures on the \nproduct of potatoes, in the same soil, with the same sort, and \nunder the same management. One experiment was on the eyes \nalone^ or small cuttings ; and the other on the xvfiole root ; so \nthat the increase from these also may be compared. The sort \nplanted was the White Round, on a clean sandy loam, well \npulverized, in rows two feet asunder, twelve inches distant in \nthe row, and six inches deep. \n\n\n\nTABLE o/EXPERIMENTS ivith the EYES only, plantedon tJic 12th Jlpril 18\xc2\xab). \n\nMAMJUE. rnOTtUCT. \n\n.1. Pig-\'s (lung -..--. 1 Ijag and liulf, //er /j<^. \n\n2. M(nvn f^ass ------ 1 bag- and 2 bushels. \n\n3. Sheep\'s dung ----- 1 bag and 1 peck. \n\n4. Coal-a.shc.s ------ 1 bag and 1 peck. \n\n5. Hen\'s dung 1 bag and 1 peck. \n\n6. ^>ld rags 1 bag 2 gallons. \n\n7. Garden rubbish 1 bag 1 gallon. \n\n8. Horse-dung ------ 1 bag 1 gallon, \n\n9. Turf-asliea \xc2\xbb----- I bag 1 gallon, \n\n10. Turf-dust -...--. 1 bag. \n\n11. River mud ..--.. 1 bag. \n\n12. Cow dung 1 bag. \n\n\n\nTABLE of EXPERIMENTS -mth the WHOLE ROOT, planted on the XOtV \n\nAfml 1811. \n\nMANUnU. PRODUCT. \n\nI. Pig\'s dang _..,,. ^ bag ." pcckj, per Ivrf^ \n\n\n\n70 EXPERIMENTS WITH MANURES. \n\nMAVUllE. PUOTiUCT. \n\n2. Sheep\'s dting 1 ba^ and half. \n\n3. Coal-ashes 1 bag- and half \n\n\xe2\x80\xa2 4. Old rags 1 bag and half. \n\n5. Mown grass 1 bag, 2 busii. 2 pecks, 1 gail. \n\n6. Hen\'s dung 1 bag 2 bushels. \n\n7. River mad 1 bag 1 buslicl. \n\n8. Turf ashes 1 bag, 3 pecjp, 1 gallon. \n\n9. Horse-dung 1 bag 3 pecks. \n\n10. Garden rubbish ----- 1 bag 3 gallons. \n\n11. Turf-dust 1 bag 3 gallons. \n\n12. Cow-dung - 1 bag 3 gallons. \n\nOn reviewing the two Tables, we may perceive, that though \nthe relative powers of the manures may vary a little, Ironi ac\'\' \ncidental causes, yet the increase from the Whole Root, us tried \nagainst that from the Eyes with the same manure, is uniformly \nso much greater as to prove decisively that it is more profitable \nto set either a Half or Whole Root, than to plant Eyes. The \nauthor of the Experiments also informs us, that in digging up \nthe potatoes, he found those produced from the eyes much \nsmaller. \n\nTo the passage above quoted (p. 68,) Sir H. Davy subjoins : \n" The question of the proper mode of the application of the \ndung of horses and cattle, however, properly belongs to the ar^ \ntide of composite manures ; for it is usually mixed in the farm- \nyard with straw, offal, chaff, and various kinds of litter ; and \nitself contains a large portion of fibrous vegetable matter." See \nnext section, Management of Manure from the Home- \nstead. \n\n7. Hog-dung\xe2\x80\x94 according to the comparative statement above, \nCp. 68,) ranks immediately after sheep-dung, and before horse- \ndung. \n\n8. Urine. \xe2\x80\x94 All urine contains the essential elements of ve- \ngetables in a state of solution : but the various species of urine \nfrom different animals difff^r in their constituents ; and the urine \nof the same animal alters when any material change is made in \nits food. During the putrefaction of urine, the greatest part of \nthe soluble vegetable matter contained in it is dissipated : it \nshould consequently be used as fresh as possible; but if not \nmixed with solid compost, it should be diluted with water ; as \nwhen undiluted, it contains too much animal matter to form a \nproper fluid nutriment for absor]>tion by the roots of plants. \nPutrid ui^ine abounds in ammoniacal salts j and though less ac- \ntive than fresh urine, is a very powerful manure.* \n\n\n\nMANAGEMENT OF MANURE FROM THE HOMESTEAD. \nComposite Manure. \xe2\x80\x94 Under the head X. 6. it has been no- \nticed, that the consideration of the right mode -of applying the \n\n* Elements of Agricultural Chemistry, p. 201. \n\n\n\nHOMESTEAD MANURE. 71 \n\nDunjT of Cattle, on a large scale, belongs to the article Compo- \nsite Manure; because it is mixed ni the farm-jar d with straw- \nlitter, and with various kinds of vegetable offal, which itself \ncontains a large proportion of hard fibrous matter. \n\nThe remarks scattered in the Elements of Agricultural Che- \nniisiry on this subject are thrown together in the following ab- \nstract. \n\nProfessor Davifs Theory on Composite Manure. \n\nA slight incipient fermentation is undoubtedly ot use in the \ndunghill ; for by means of it a disposition is brought on in the \nwoody fibre to decay and dissolve, when it is carried to the \nland, or ploughed uiio the soil, \xe2\x80\x94 and -woody jihre is always in \n.p-eat t;xccss m the refuse of the farm. Too great a degree of \nfermentation is, however, very prejudicial to the composite ma- \nnure in the dung-hill : it is better that there should be no fer- \nmentation at all before the manure is used, than that it should \nbe carried too far. This must be obvious, from the following \nconsiderations. The Professor\'s arguments may be arranged \nunder five heads : four theoretical j and one practical. \n\nI. " An immeasurable quantity of substance disposed for con- \nversion into iood tor plants is then suffered to escape in the \nform of drainings and vapour. During the violent fermentation \nwhich is necessary for reducing farm-yard manure to the state \nin which it is called short-muck^ not only a large quantity of \nfluid, but like .vise of gaseous matter, is lost ; so much so, that \nthe dung is reduced one-half, and from that to two-thirds or \nmore in weight : now the principal elastic matter disengaged is \ncarbonic acid ith some ammonia; and both these, if attracted \nby the moisture in a soil, and retained in combination with it \nare capable of becoming nutriment to plants." \xe2\x80\x94 In aid of this \nreasoning, the Professor relates an experiment, from which he \nconsiders that he has obtained particular proof that the gaseous \nmatter from fermenting dung is of great utility to growing \nplants. He introduced the beak of a retort filled with ferment- \ning manure, consisting principally of the litter and dung of cat- \ntle, into the\'border of a garden among the roots of some grass. \nIn less than a week, a very distinct effect was produced upon \nthe spot exposed to the influence of the matter disengaged in \nfermentation ; the grass gr ;w with much more luxuriance than \nin, any other part of the garden. \n\nII. \xe2\x80\xa2\xe2\x80\xa2\' There is (continues the author of the experiment) an- \nother disadvantage in the loss of heat ; which, if excited in the \nsoil, is useful in promoting the germination of the seed, and in \nassisting the plant in the first stage of its growth, whf-ii it is \nmost feeble and liable to disease ; and the fermentation of ma- \nnure in the soil must be particularly favourable to the wheat \n\n\n\n72 MANAGEMENT Of \n\ncrop, in preserving a genial temperature beneath the surfacCj \nlate in the autumn, and during winter." \n\nIII. " Again, it is a general prniciple in chemistry, that in \nall cases oi decomposition, substances combine much more \nreadily at the moment of their disengagement than after they \nhave been perfectly formed. And in fermentation beneath the \nsoil, the fluid matter is applied instantly, even whilst it is warm, \nto the organs of the plant ; and consequently is more likely to \nbe efficient than in manure that has gone through the process of \nfermentation, and of which all the principles have entered into \nnew combinations.\'* \n\nIV. The Professor, in another place, reminds us, that the \nultimate results from an excess of fermentation in a heap of \nmanure are like those of combustion. \n\nV. " A great mass of facts may be found in favour of the \napplication of farm-yard dung in a recent state. Within the \nlast seven years, Mr. Coke has entirely given up the system \nof applying fermented dung; and he informs me (says Sir H. \nDavy) that his crops have been since as good as ever they were, \nand that his manure goes nearly twice as far." \n\nVI. Objection noticed by the Professor. \xe2\x80\x94 Sir Humphry then \ncandidly states an objection made by many practical Agricul- \nturists to his system for managing composite manure. " A great \nobjection against dung but slightly fermented, is, that weeds \nspring up more luxuriantly where it is applied." \n\nTo which he answers : " If seeds are carried out in the dung, \nthey certainly will germinate ; but it is seldom that this can be \nthe case to any extent: and if the land is not cleared of weeds, \nany kind of manure, fermented or unfermented, will occasion \ntheir rapid growth." \n\nVII. His oxvn sPractical Application of the above Theory. \xe2\x80\x94 It \nis to be observed, that the Professor admits the beneficial ten- \ndency of a slight or incipient fermentation in mixed heaps. To \nregulate the practice of fermenting composite manures, as the \nbasis of the heap may vary, these are his two general principles : \n1. Whenever manures, consist principally of matter soluble in \nWATER, their ferltientation or putrefaction should be prevented \nas much as possible. 2. The only cases in which putrefaction \ncan be useful, are when the manure consists chiefly of animal or \nvegetable fibre. \n\nAgreeably to the al)ove principles. Sir H. Davy then gives \nDirections for the Manageynent of Farm.yard Dung in the Hcap^ \nand for its Application to the Soil: of which the following is the \nsubstance. \n\n" Where farm-yard dung cannot be immediately applied, the \ndestructive fermentation of it should be prevented as much as \npossible. For this end, the dung should be kept dry, and unex- \nposed to the air ; for moisture and contact with the oxygene of \n\n\n\nHOMESTEAD MANURE. 73 \n\nthe atmosphere tends to excite fermentation. To protect a heap \nirotu rain, a covering of compact marie, or of a tenacious clay, \nshould be spread over the surface and sides of it.* \n\n" Watering dunghills is sometimes recommended for check- \ning fermentation : but this practice, although it may cool the dung \nfor a short time, is inconsistent with just views ; for moisture is \na principal agent in all processes of decomposition : dry fibrous \nmatter will never ferment. \n\n" If a thermometer plunged into the dung does not rise to above \n100\xc2\xb0 of Fahrenheit, there is little danger of much aeriform mat- \nter flying off. If the temperature is higher, the dung should be \nimmediately spread abroad. \n\nWhen dung is to be preserved for any time, the site of the \ndunghill is of great importance. In order to have it defended \nfrom the sun it should be laid either under a shed, or on the \nnorth side of a wall. To make a complete dung repository, the \nfloor should be paved with flat stones, a little inclination being \nmade from each side towards the centre : in the centre there \nshould be drains, connected with a small well, furnished with a \npump, by which any fluid matter may be collected for the use of \nthe land. It too often happens that the drainings of the dung- \nhill are entirely wasted." \n\nThe Professor then adverts to the application of littery dung \non pastures. " If slightly fermented farm-yard dung is used as \na top dressing for pastures^ the long straws and unfermented ve- \ngetable matter remaining on the surface should, as soon as the \ngrass begins to rise vigorously, be removed and carried back to \nthe dunghill : in this case no manure will be lost, and the hus- \nbandry will be at once clean and economical." \n\nFree Remarks on the Theory^ and on its Practical Applica- \ntion. \xe2\x80\x94 Having finished the above compendium of Sir H. l)avy*s \nViews on the Management of Manure from the Homestead, \nthe Writer subjoins a few Strictures and Suggestions in regard \nto the five principal grounds on which the Professor recommends \nthat composite manure should be, under common circumstances, \nbut slightly fermented before it is spent on land. \n\nThe first objection of the Author of the Elements to the re- \nduction of farm-yard dung to the state o{ short-muck^ relates to \nthe loss of FLUID, and of gaseous matter. \n\nEvery person must admit that the subtraction of a fluid sub- \nstance from a mass of dung must diminish the strength and rich- \nness of the intended manure ; and though in some cases the bulk \nof the fluid may be rain water or waste water accidentally fall- \ning upon the dunghill, yet it cannot be denied that part of the \nessence of the dung must be carried away in the drainings. Ne- \nvertheless, where the drainings of the dunghill can be saved in \n\n\xe2\x80\xa2 Elements of Agricultural Chemistry, p. 20fl. \nK \n\n\n\n74 MANAGEMENT OP \n\na proper receptacle, in order to be applied to heaps of dry com- \npost, or to land under tillage, thtre is no loss to the Agricultu\xc2\xbb \nrist in the separation of the fluid part of the manure. \n\nSir Hampry Davy\'s plan of a well to catch the drainings of a \ndur.ghill is sufficiently practical; and where the nature of the te- \nnure makes it worth the cultivator\'s while to have such a well, \nis perhaps as good a method as can be devised for obviating the \nloss of fluid matter. \n\nIn other cases, where a reservoir cannot be formed for the \ndrainings from an accumulating mass of dung, it will be a ser- \nviceable expedient to prepare a thick layer of good earth (cul- \ntivated mould or rich loam,) raised at the edges as the basis of \nthe intended dunghill: which layer of earth, by continually recei- \nving the moisture draining from the superincumbent dung,will be \nas valuable for manure, when the whole is removed as the dung \nitself. \n\nThe escape of gaseous matter forms another part of the ob- \njection to fermenting Uung, above cited from Sir H. Davy. Un- \nder a previous head, Impkovement of Soils, V. By FalloW\' \ni7ig\\ the writer, in endeavouring to meet a speculative objection \nto fallowing, founded on the escape of gaseous matter, has offer- \ned some considerations why that should not be estimated as a \nloss. (p. 28 31.) \n\nAs to the escape of gaseous matter from fermenting dung, it \nis not easy to prevent it, if the dung lie any where but in the \nvery bosom of the land. Perhaps, however, when dung must \nbe partly decomposed before it is applied, a case of mould over \nthe heap would attract, and hold in combination, much of the \ncaibonic acid and ammonia which would else escape in vapour. \nSuch mould, like that laid underneath, would be imbued with \nsustenance for plants, but in a less degree, and only in propor- \ntion to the completeness of the fermentation. But the coverir.g \nof earth, would in some instances be liable to be burnt, and in \nothers be apt to prevent the free fermentation necessary to dis- \nsolve woody fibre. \n\nAs to the experiment of the vapour directed frorn the beak \n6f a retort on some grass growing in a border, as recorded by \nthe Professor ; it may be in place to observe, that the effect on \ngrass, of which the species is not mentioned, fails to afford a \nsufficient criterion : \xe2\x80\x94 had the subject of experiment been a kit- \nchen esculent requiring a rich soil and yet impatient of rank ma- \nnure, and had the trial been protracted till the time of flowering \nor fruiting, some satisfactory conclusion might have been form- \ned with regard to the influence of the gas on the growth of the \nplant and the flavour of its edible produce. \n\nThe second objection to the fermentation of a heap of dung \nintended for manure, at a temperature exceeding 100 degrees of \nFahrenheit as a maximum, adverts to the loss of heat. The \n\n\n\nHOMESTEAD MANURE. 7$ \n\nway in which the loss of heat is supposed by the Professot to \noperate, involves so much that is hypothetical, that an appeal to \nthe result of trials in which the different causes that may ope- \nrate are not distinctly measured will not be decisive in favour of \nthe theory ; because it frequently happens that an effect which \npretty constantly attends a particular practice is attributed to the \nwrong cause. Now it appears contrary to nature, and to the \nprinciple on which a warm climate is imitated in any forcing de- \npartment, to excite the roots of a plant with any degree of arti- \nficial heat, unless there be some cover or weather-screen to de- \ntani the warm vapour and create an atmosphere corresponding \nto the soil ; and the seed or root ought to be protected from the \nfermenting substance by a coat of earth. \n\nThe disadvantage from the loss of heat in manure may there- \nfore be more correctly attributed to the. entire exhaustion of the \nfermenting principle, and to the want of its influence in commu- \nnicating a kindred fermentation to dry fibrous .natter already in \nthe clod, and so reducing it to a state of aliment for plants. On \nthe other hand, it may conduce to the health and vigour of the \nplants to have the fermentation in the soil conipleted before the \nnew crop is put in, so that the growing roots may not be in con- \ntact with putrefying substances. \n\nThe third ground of argument for postponing the decompo- \nsition of manure till it be imbedded in the soil is drawn from a \nprinciple in chemistry, that substances kscaping -from de- \ncomposed BODIES ENTER INTO NEW COMBINATIONS MOST REA- \nDILY WHEN FIRST DISENGAGED. There seems no reason for \ncontesting the practical inference deducible from this principle \n\xe2\x80\x94 provided the intention be confined to promoting the combina- \ntion of the matter disengaged from the dissolving body intimate- \nly with the soil : either by casing the dunghill with mould to be \nused as compost, or by burying the manure in a clod when par- \ntially fermented, and before it is much exhausted of the rudi- \nments of vegetable matter iiy drainings or vapour ; taking care \nto have the manured soil afterwards properly turned and expo- \nsed to the air before it is sown or planted, so that whatever gase- \nous matter has a natural tendency to fly off into the air may free- \nly escape. But the theory on which a beneficial influence is an- \nticipated from applying the *\' fluid matter while it is warm to \nthe organs of the plant," seems to be repugnant to the process \nof nature, and closely allied to that hypothetical branch of the se- \ncond ground of argument already objected to. Nor is there any \nproof that a fermenting substance is fit food for a living plant ; \nthe residuum of animal and vegetable substances purified by free \nexposure after decomposition seems, in the circle of natural ope- \nrations, to contribute chiefly to the bulk of ne^v plants : but w hen \ncrude animal or vegetable remains. Or the fluid or solid sub- \nStances rejected in the composition of animals, are administer \n\n\n\n76 MANAtiENEJSX OF \n\ned to growing plants, the rank manure appears, irom numerous \nexperiments, to make them flourish unnaturally at first, and then \nto induce disease and premature decay. To give an instance \nfrom each class, this is the known effect of oil, tree-leaves, urine, \nnight-soil. \n\nThe utmost extent of the fourth objection will bring the dung \nwhich has cuswdWy fir e-fanged on a par with the ashes of various \nburnt vegetables. How far the condensed power of these (a \nspecific sort being chosen for the desired effect) has been found \non particular soils cropped with suitable plants, to exceed that \nof the very same sort of manure in an unfermented state, or in \nany stage of decomposition short of combustion, is well known \nto practical cultivators, and has been partly noticed in p, 65. \nThis objection is again adverted to under Recapitulation^ sect. 5. \nFire-fanging, regarded as a mischief, as an excess beyond the \nfarmer\'s design is easily prevented. \n\nThe fifth argument is entirely practical, and the authority ad- \nduced in its support one of the highest. If, under different lo- \ncal circumstances, other cultivators are led to the same conclu- \nsion by similar experiments carried on for a sufficient course of \ntime, this single argument will have more weight than the other \nthree ; because there can be no competition between theory and \nexperience. \n\nIt is nevertheless to be observed, that the statement made \nabove, after Mr. Coke, is not clear in its import : it can have the \nweight just conceded to it only on the construction, either that \nsome of the manure made on the farm that was expended under \nthe old system is disposable for some other purpose under the \nnew, \xe2\x80\x94 or that some expense in fetching manure from distant \nplaces, that had used to be incurred, is saved : but if the state- \nment, " that the crops are as good as ever they were, and that \nthe manure goes nearly twice as far," mean only that the dung \nwhen now expended is nearly twice as much in bulk or weight, \nand covers the surface of the field more thickly in the same pro- \nportion, the benefit is merely illusory, \xe2\x80\x94 the crop is confessedly \nnot increased ; while the carriage of the dung to the land must \nbe heavier, and the labour of spreading it greater. \n\nThe following Experiment of Mr. Wright, recorded in the \nAgricultural Magazine^ N. S, No. 3, is a valuable contribution \non this subject. \n\n\n\nHOMESTEAD. \n\n\n\n77 \n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n6 \n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n0) \n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\no. \n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\nU5 \n\n\nUl \n\n\n\n\n\n\n\n\n\n\n\n\nc3 \n\n\n\n\no \n\n\nCJ \n\n\n\n\n\n\n\n\n\n\n\xe2\x80\xa2c 5 1 \n\n\n\n\n<l> \n\n\nC \n\n\n\xe2\x80\xa2 \n\n\n\n\n\n\n\n\n\n\nc c \n\n\ny> \n\n\nC- . \n\n\nO \n\n\nr-^ \n\n\n\n\n\n\n\n\n\n\n3 ^ \n\n\n^ \n\n\nc 1^ \n\n\n\n\no \n\n\n\n\n\n\n\n\nc :\xc2\xa7 \n\n\nCO \n\n\n^ 3 \n\nen ^ \n\nJo \n\n\n1 1 \n\nCO \n\nc \n\n\n=3 \nJO \n\nCJ \n\n\nPfiJ \n\n\n\n\n\n\n\n\nK \n\n\n\n\nr4 \n\n\nbO \n\n\n\n\nP \n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n;?; \n\n\n\n\n\n\n\n\n\n\n\n\n9 \n\nh.n \n\n\n\n\n\n\n\n\n\n\n\n\n\n\n<i \n\n\n\n\n\n\n\n\n\n\n\n\n\n\nO \n\n\n\n\nS \n\n\n\n\n\n\nN \n\n\nS 3 \n\n\n=3 \n\n\n-^ \n\n\nat \n\nC \n\n\n\n\nCO \n\n\n\n\n\n\n2 \n\n\nE o \n\nOD C3 ^ \n\n\n\n\n\n\n4) \n\n\n\n\nQ \n\n\n\xe2\x80\xa2\xe2\x80\xa2 \n\n\n\n\n.\xe2\x96\xa02 \n\n\n09 \n\n\n^ c \n\n\n3 \n\n\n^ \n\n\nli \n\n\n\n\nis \n\n\n^ c"> \n\n\nCO \n\n\n\n\nCO \xe2\x80\xa2S\'o \n\n\n-\xc2\xb0 \n\n\n\xc2\xbb\xe2\x80\x94 4 \n\n\n\n\n\n\n5 \n\n\n\xc2\xab S" \n\n\n^ \n\n\no \n\nCO \n\n\n\xe2\x80\xa2H Q U \n\n\n00 \n\n\neg \n\n\n1 \n\n\n0) \n\n\nbo \n\n\n\n\n3 \n00 \n\n\n\n\nCO \n\n\n\n\no \n\n\n\n\nn \n\n\n\n\n\n\nti (U \n\n\n\n\n\n\n0) \n\n1 \n\n\no \n\n1 \n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\xe2\x80\xa2^.s \n\n\n\n\nEh \n\nH \n\n\nho \n\nt3 \n\n\n\n\n\n\nCo \nN. \n\n\nin \n\n(U \n\na. . \n\n\n2 to \n\n\n\n\n;zi \n\n\n1 \n\n\nc \n.2 \n\n\n3 ti c \n\n\n\xc2\xab; \n\n\nCO H \n\n\n^ fl \n\n\n\'3 \n\n\n\n\n1 \n\nO \n\n\no \n\n"a. \nc \n\n\nCO J?i- \n\n5S \n\n\n\n\nCO \n\n\n:: -5 5 \n\n\ni/J \n\n3 \n\n-a \n\no \n-* \n\n\nW \n\n\n1 \n\n\nO \nO \n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\no \n\n\nC^ \n\n\n\'55 \n\n\n\n\n\n\n\n\n\n\n5 \n\n\n\n\ns \n\np \n\na\' \n\n\nC4 \n\n\n\n\n05 \n\no \n\n\nair \n\n\n\n\n-\xc2\xab1 \n\n\n\'^ \n\n\n\n\no \n\nQ \nO \n\nC \n\n\n_ ^ \n\n(i1 \n\n\n1 \n\n00 \n\n\no \n\nCO \n\n\no \xe2\x80\xa2; \n\n\na \n3 \n\nCO \n\nCO \n\n\n3h \n1? \n\n\n\n\n\n\n1 \n\n\n\n\n\n\n\n\n\xe2\x80\xa2J \n\n\n\n\n\n\n, \n\n\n. \n\n\n\n\n\n\nO \n\n\n\n\n\n\no \n\n\n\n\n, \n\n\n\n\n\n\n\n\nU \n\n\n\n\n\n\n> \n\n\n\n\n\xe2\x96\xa0|^ \n\n\n\n\n\n\nr;-A>^ \n\n\n\n\n\n\n\n\ncn \n\n\n\n\nF \n\n\n-i :\xc2\xab J \n\n\n$; o \n\n\n^ \n\n\n\n\n\n\n\n\n\n\n\n\nS \n\n\n5 So \n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\nc. \n\n\n\n\n\xc2\xbb \xe2\x80\xa2 o \n\nC-5 9 \n\n\n^\xe2\x96\xa03 & \n\n\n\n\n\n\n\n\n\n\ng \n\n\nO O rt \n\n\no -s: ? \n\n\nfc. -Q r; \n\n\n\n\n\n\n\n\nCO \n\n\n\n\n.o.^ \n\n\no.t^ \n\n\n-\xe2\x96\xa0^1 \n\n\n\n\n\n\n\n\n\n\n\n\nto \n\n\n\xe2\x96\xa0(NO \n\n\n^(N^ \n\n\n^ c^* o \n\n\n- \n\n\n\n\n\n\n\n\n\n\n^ \n\n\n!N \n\n\n1^0 \n\n\n.. ^ . . -J] \n\n\n\n78 MANAGEMENT OP \n\nTo complete this experiment, there wants a notice of propor- \ntion of weight which a heap ot rotten dung would lose in eight \nmonths : three tons of strawey dung would scarcely make more \nthan a ton and a half of completely rotted dung : but when dung, \nis reduced one-third in weight, the fermentation may be consi- \ndered far enough advanced for agricultural pur|\'Oses in general. \n\nSupposing the original quantity to have been on a par, the \nabove experiment would be, in every instance but the first, in \nfavour of thcrotted dung: the small inferiority in the case ot \nthe turnips may be attributed to there being an excess of manure \nabove what the plant required; so that had but one ton been put \non for the turnips, and the other ton been reserved for the se- \ncond crop, the benefit to both crops might have been much en- \nhanced. It appears from the Experiments of Mr. Hassenfratz, \ncited in Dr. Thomson\'s System of Chemistry^ that the times in \nwhich manures begin to produce, their effects, and the length of \ntime for which they operate, are proportioned to the degree of \nputrefaction under which they are applied. Having manured \ntwo pieces of the same kind of soil, the one with a mixture of \ndung and straw highly putrefied, the other with the same pro- \nportions of dung and straw newly mixed, and the straw almost \nfresh, he observed, that during the first year, the plants which \ngrew on the putrefied dung produced a much better crop than \nthe other ; but the second year (no new dung being added) the \nground which had been manured with the uii putrefied dung pro- \nduced the best crop : the same thing took place the third year ; \nafter which, both seemed to be equally exhausted. Ano- \nther experiment of the ^ame chemist made on shavings of wood, \nplaces in a striking light the slow progress of the effects of ma- \nnure which decomposes slowly. He allowed shavings of wood \nto remain for about ten months in a moist place, till they began \nto putrefy, and then spread them over a piece of ground, by way \nof manure. The first two years, this spot produced nothing \nmore than others which had not been manured at all ; the third \nyear it was better ; the fourth year it was still better ; the fifth \nyear it reached its maximum of fertility ; after which it decli- \nned constantly till the ninth, when it was quite exhausted. \n\nWhen dung moderately fermented has been applied to land \nsown with turnips, it has been observed that the fly is not so apt \nto take the turnip as when the dung has been fermented in a de- \nficient or excessive degree. This is not to be attributed so much \nto the vapour from the dung being offensive to the fly, for a high \nheat is congenial to the insect, as to the plants making such quick \nprogress from a free but well-tempered excitement as to get \ninto the rough leaf and past danger before the insect lights \nupon it. \n\nIn the sixth place, the abstract above presented from Sir H. \nDavy\'s Lectures, notices a main objection to the expenditure of \n\n\n\nllOMESTEAD MANURE. 79 \n\n"lung on land when but slightly Jermented, which is, that weeds \nspring up more luxuriantly when dung in that state is applied. \nBy way of rei)elling this objection, the Proi\'essor mere iy alleges, \nthat " it can seldom be the case to any extent that seeds are \ncarried out in the dung. \n\nNot to dismiss an important objection without obviating it, \xe2\x80\x94 \nIf the system of using composite dung when green, or but slight- \nly fermented, be adopted, the following precautions and limita- \ntions seem necessary in collecting the materials. From the \ndunghill intended to be so expended must be excluded many \nthings naturally mixing in the refuse heaps of a farm and gar- \nden. These things may be comprehended under three classes : \n\xe2\x80\x94 1. Weeds; 2. Vegetable remains, containing woody fibre ; 3. \nParticular kinds of dung which are pernicious without being \npulverised. But articles which contribute so materially to the \nmass of vegetable manure need not be lost. Let one dunghill \nbe set apart as \xc2\xa3i rot-heap for such substances as it is requisite \nentirely to decompose before they are carried to the land, par- \nticularly weeds and woody fragments. \n\nThe heap to which litter and dung is carried for u^e when \nslightly fermented should be kept at a distance from the rot-heap, \nand nothing should be admitted into it but what is easily solu- \nble from the effects of heat and moisture. \n\nAn intelligent friend named in the Preface to the " Practical \nGardener," as a contributor of several valuable additions to that \nposthumous work of Abercrombie \xe2\x80\x94 who derives his opinions \non practical points from a long course of experience in the di- \nrection of large horticultural and farming establishments, en- \nlightened by a general acquaintance with the best authors on ru- \nral economy \xe2\x80\x94 has communicated to the Writer several observa- \ntions in respect to the application of dry litter and unfermented \ndung on land. \n\nIn the above review of Sir H. Davy\'s system, under the head, \nImi\'Rovementof Soils, IX. 17, " Dry straw and spoiled hay," \na method of employing these materials without fermenting is \nsuggested. If the expense of cutting dry straw by a machine to \nprepare it for manure should not prove too great, it may be worth \nthe cultivator\'s while to employ it as above recommended on \nLAND UNDER THE PLOUGH OR SPADE, provided the soU is rich \nenoitifh in vegetable aliment to sustain the expected crop without \najiu ifntnediate benefit fro fu the mamire. Manure so applied will \nrather assist the second crop than the first. \n\nIncontestable Exception. In land to be sown with barley, lit- \nterv unreduced dung has a remarkably bad effect. \n\nWith regard to pastures, the agriculturist above alluded to \nentertains, from experience, from observation, and from reason- \ning on theoretical grounds, a decided opinion, that neither hay \nnor straw, nor any haulm, should be applied to the surface of \n\n\n\n80 MANAGEMENT OP \n\ngrass-land before it has undergone a sufficient fermentation to \nensure its easy and expeditious decoiuposition when spread \nabroad. On grass-land, the object of combining as much as pos- \nsible of the manure with the soil is more likely to be promoted \nby spending it in a stage already advancing toward complete de- \ncomposition, than by lodging on the gr^ound strawy litter nut at \nall fermented ; while the face of the verdure will not be so long \nencumbered. Nor will the gaseous matter escaping from litter \nleft slowly to rot in a pasture more benefit the land than if it had \nexhaled from a dunghill in the homestead. It is altogether dif- \nferent in relation to land under the plough or spade ; by turning \nin the manure as soon as circumstances may render fit, when \nfermentation has just commenced and the long litter is some- \nwhat reduced, the fluid matter is secured for the enrichment of \nthe land without any extraordinary pains and without injury, be- \ncause the crop is aftcrxvards put in : the gaseous matter is also \nsecured , but whether permanently or not, may be doubted, be- \ncause substances disposed to take a volatile form will fly off \nwhenever the bosom of the soil is opened to the air by tillage. \n\nIn order to preserve the fluids draining from dung, without \nthe expense of a reservoir, or the trouble of laying a terrace of \nmould as the site of a dunghill, \xe2\x80\x94 the composite dung or litter, \nprevious to fermentation, may be laid in heaps on the field where \nit is to be spent, and then brought to ferment by the same means \nas dung preparing for a hot-bed, and kept fermenting for about \nthe same time before it is spread. This might be done even on \npasture : but it is worth consideration, 1". Whether the spread- \ning of a substance which has to go through the whole process of \nfermentation over a surface of grass may not materially injure \nthe life oi* the health of the herb. 2\xc2\xb0. Whether a smaller pro- \nportion of manure, if laid on pasture in a state approaching that \nof vegetable mould, may not be more beneficial, by soon mixing \nwith the soil, and doing no injury to the crop, than the larger \nquantity of litter, which has to lie for a length of time heating and \npartially rotting before it is dissolved and imbibed by the sward. \nThis is stated as a subject for further inquiry, in deference to \nthe Professor : but a practical farmer who has tried the matter \nis decidedly of opinion that dung must be considerably reduced \nto be of unqualified benefit to pasture. \n\nTo obviate one princii)al objection against employing strawy \nunfermented dung as a top dressing for pasture^ Sir H. Davy \nproposes to carry back to the dunghill the long straws and un- \nfermented remnants of vegetable matter. This mode of re- \nmoving the encumbering litter would be attended with an ex- \npense hir be}\'ond the value of the strawy refuse : and yet, were \nsuch litter left in a pasture after the new herbage shoots, the \nhusbandry would be foul ; and, in the loss of manure, with ia- \njury to the crop, doubly unprofitable. \n\n\n\nHOMESTEAD MANURE. 81 \n\nWith respect to the dung of cattle in a green or unfermented \nstate, it is said, under the head Improvement of Soils, X. 6. \nas a quotation from Sir H. Davy : " If the pure dung of cat- \ntle is to be used as a manure, like the other species of dung \nwhich have been mentioned, there seems no reason why it should \nbe made to ferment, except in the soil." \n\nThe first ground of exception to this, is offered by Mr. \nWright\'s experiment already quoted, proving that green cow- \ndung is pernicious on land sown with barley. \n\nAs to sheep-dang, deer-dung, hog-dung, and horse-dung, in \na green state, they may be applied, either singly or mixed, to \nploughed land in general with a good effect. The hot and fiery \nkinds of dung should not be laid on pasture, unless tempered \nby mixture with the colder sorts, or unless the quantity applied \ncan be minutely divided so as to facilitate both the equal dis- \ntribution of it over the field, and its speedy sinking into the sur- \nface. \n\nThus the dung of hard-fed horses should not be used green \non pasture land, because of its heating quality ; but it may be \nturned into ploughed land with obvious advantage. If, how- \never, an arable field is in want of instant benefit frOm manure, \nsuch part of the manure as consists of horse-dung ought to be \nfermented ; because the dung of an animal not chewing the cud \ncontains much undigested inatter, \xe2\x80\x94 straws of grasses, or grains \nof corn, according to its food, broken into small parts, but not \ndissolved : whereas the dung of most cattle that ruminate soon \nputrefies in the soil. Cow-dung alone forms an exception ; some \nof its peculiarities are noticed below. \n\nSheep\'s dung may be applied green, either to pasture or \nploughed land. The urine of sheep, richer than that of other \ncattle, except perhaps deer, is of equal utility with their dung. \nThe dung of deer is as well adapted to improve pasture with- \nout long encumbering the surface, as that of sheep. If sheep \nare folded, the sooner the dung is ploughed into the land the \nbetter. \n\nNeat\'s dung in a recent state is cold. Another cause of its \nbad effect alone is its tendency to cake, so that it has a tenacity \nlike that of clay : hence it is not easilv pulverized, so as to be \nequally distributed over a field, and intimately blended with the \nsoil. When laid pure in a mass, it does not naturally heat ; but \nit may be brought to ferment b)\' a mixture of straw and hot \ndung. If kept for a long time vmmixed with other dung, it \nundergoes a change within itself, without losing the vegetable \npart of its substance by fermentation. When the dung of oxen \nis prepared as the main ingredient for exotic fruit-bearing shrul^s, \nit should be kept for three years by itself, to lose its tenacity : \nafter which period it is full of aliment for plants, perfectly \n\n\n\n82 MANAGEMENT (>V \n\ndivested of th.it rankness which is offensive to the roots of trees, \nand easily pulverized. \n\nWhere several dung-heaps are collected near a homestead, \nit niay be proper to distribute the litter to each, with some \nattention tw the kind ot crops lor which the manure is to be \nspent. Stable dung, also the straw of corn and j)ulse crops, \nmight be set apart to augment the bulk of manure preparing \nfor arable land : offal hay, the sweepings of the hay-loft, and \nthe decayed substance of green crops, Would revert, with \nmuch fitness, in the shape of compost, to fields of pasture. \nThis is only an extension of the principle on which malt-dust \nhas been employed as a manure for barley, with peculiar success. \nLands laid down under grass merely to prepare them for corn \nshould be treated when manured as arable, in respect to the \nquality of tlie manure, especially when on the point of being \nbroken up. \n\n\n\nThe following practical outlines on important points in the \nManagement of Manure from the flomestead are drawn from \na recent work of great authority, to which e have more than \nonce appealed. As far as they correspond with communications \nalready given, it is a satisfactory corroboration : if they manifest \nany shade of rei)ugnance to practices or opinions detailed in \nthis treatise, the circumspection of the Rt^ader will be usefully \nawakened. \n\n" In the Southern counties of Scotland at the present time, \nthe crops are cut very low : the straw and haulm is used for \nabsorbing the excrementitious matter of domestic animals. The \njuices of the dunghill are carefully preserved from waste ; \nwhile the heap is greatly augmented and enriched by the con- \nsumption of green clover and turnips, and made to undergo \na greater or less degree of fermentation and putrefaction accord- \ning to the crops and soils to which it is to be applied. Dung is \nnever laid on foul land, \xe2\x80\x94 very rarely on pasture or hay grounds, \nas in England ; but it is distributed economically over a third \nor fourth part of the land in tillage, and thus over thie whole \nfarm in regular succession, at a tiine when the soil is in a state \nto receive the greatest benefit from its operation, and in that \nstage of a rotation when the land most demands that method \nof recruiting it. \n\n" For a drilled turnip crop, it is indispensable that the dung \nbe well rotted, and capable of instantly hastening the growth \nof a plant which in its infancy is exposed to the attack of seve- \nral deadly eneniics. ~ But an abundant crop of potatoes may he \nraised by the use of fresh unfermented manure ; and for clay \nsoils generally, whether tlie manure be aiiplied to a fallow unde.r \n\n\n\nHOMESTEAD MANUIIE. 83 \n\npreparatf(Mi for nn autumn sowing of wheat, or for beans, as it \nhas a much longer time to decompose in the. soil, a less degree \nof putrefaction is required than for a turnip crop."* \n\n\n\nRecapitulation. \xe2\x80\x94 For the management of manure from the \nhomesteacl, tne following rules of practice seem to result from \nthe preceding discussion of theoretical print ipks, in connection \nwith some recorded experiments. \n\n1. To ferment dung-heaps from which mown or pulled weeds \nand woody fibrous\' refuse are excluded, until they have lost one- \nthird of their weight ; and even this in districts where manure \nis scarce, and where the motives for spending it in the most \neconomical way are the strongest. To ferment it to this mini- \nmum degree previously to spending it on arable land in au- \ntumn, or at a season when some tinxe will elapse before the seed \nis put in. To ferment and purify it in a greater degree when \nintended for use just before a spring sowing. To ferment dung to \nbe spent on grass-land until the strawy materials begin to dis- \nsolve. \n\n2. To ferment dung-heaps in which weeds and fibrous vege- \ntable remains or woody offal are laid to rot, until the roots and \nseeds of the weeds and the fragments of woody matter are de- \ncomposed. This kind of heap may properly be set apart for \npasture as far as it will extend. \n\n3. To save the drainings from dunghills as much as possi- \nble. \n\n4. To disregard the loss of gaseous and volatile matters, both \nfrom the dunghill and from the surface of land ; and to estimate \nit rather as a benefit, for the reasons givt-n under " Fallowing.""\' \n(pp. 28 \xe2\x80\x94 31.) To make trial, nevertheless, low far a covering \nof earth upon a dunghill can be converted into a manure, where \nthe matter of a dense and rapid exhalation niav seem worth in- \ntercepting. \n\n5. To avoid fermenting the dung-heaps described under 1. \nuntil the fibrous texture is totally destroyed, and the mass of ma- \nnure becomes cold and soft, \xe2\x80\x94 where the manure is to be expend- \n*;d on a large tract, particularly on lands under the plough, \xe2\x80\x94 \nchiefly for these two reasons : first, to oln-iate the loss of fluid \nmatter where a reservoir cannot he contrived ; and secondly, on \naccount of the exhaustion of the fermenting- principle, which \nwould be usefully set in action in foul soils ; rather than for the \n\xe2\x99\xa6jther causes theoretically assigned in the Elements of AgricidtU\' \nral Chemistry : because, admitting a principle urged by Profes- \nsor Davy, meriting a distinct notice, that the " ultimate results \nof excessive fermentation, are like those of combustion," it is \n\n\xe2\x80\xa2 r,f>rf>v:il Rf\'poil o\'.i tlin Agricullurftl State of PcoUand, in five vols. 4to. \n\n\n\n84 MANAGEMENT, &G. \n\nreasonable to conclude, from the experiment related above, on \nthe ashes of 15 cvvt. of Barley Straw, that if the quantity of \nburnt straw had equalled the weight of strawy dung, the ashes \nwould have surpassed the strawy manure in fertilizing effect. \nThe ashes of various burnt vegetables are celebrated for their \nfertilizing power. To return to the object of checking fermenta- \ntion beyond the proposed degree, spread the heap abroad. Heavy \nwatering Avill at once abate the heat ; but the heat will after- \nwards revive with increased fury, unless the stack be either trod \ndown to exclude the air, or scattered and partially dried before \nit is again allowed to ferment. \n\n6. In gardens, and on grounds cultivated on a small scale, \nand even on arable farms where rest by summer fallowing can \nbe superseded by a constant full supply of manure, the utility of \nrotted dung is far above that of strawy unfermented litter or \nslightly fermented dung ; because the latter is a nidus for in- \nsects ; also because putrefying remains, if in contact with grow- \ning plants, must tend to injure the health of many species, and \nto deteriorate the flavour of the edible parts of plants, and espe- \ncially of esculent roots. \n\n\n\nAl>DlT10A*Ali KOTE^. \n\n\n\nPage 26. " By Fallowing."] \xe2\x80\x94 While this Treatise was in the press, an ori\' \nginal critique on the \' Elements of Agricultural Chemistry,\' appeared in the \n\' P\'armer\'s Magazine.\' The Conductor of it, who possesses great advantage \nfor comparing the projects of theory with the results of practice, has ex- \npressed a deliberate dissent from Sir H. Davy\'s doctrine \' on Fallowing.\' The \ngrounds of opposition there taken coincide so closely in a few fundamental \npoints \xe2\x80\x94 and so substantially in their tenor and conclusion \xe2\x80\x94 with the observa- \ntions made on the same subject in the preceding pages, that it may be expe- \ndient to state that the passage in the Ti\'eatise (pp. 26 \xe2\x80\x94 34) was printed oft" \nbefore the publication of the Magazine, and that the MS. of it had been in \nthe hands of some friendly critics sufficiently long to establish for it an inde- \npendent origin ; having been dissected by a surgeon, weeded and pruned by \na gardener, and examined for a degree by the principal of a college. This \nstill leaves to the critique in the Magazine all the force of a corroborating \nauthority; in which light I adduce an extract from it, with much satisfaction. \nThe coincidence chiefly to be remarked, is in admitting many of the Lec- \nturer\'s positions advanced as chemical facts, and in deriving from them counter \narguments. But the points on which the Reviewer enlarges are not the same, \nand some forcible passages in his parallel course struck me as;new, the natural \neffect of free deduction without communication. \n\n" But with regard to his doctrine concerning fallowing, we diffier from him \nentirely. He thinks a clean fallow \' may be sometimes necessary in lands \n\' overgrown with weeds, particularly if they are sands which ca.inot be pared \n\n* and burnt with advantage ; but that it is certainly unprofitable as a general \n\n* system of husbandry.\' Now, we think naked fallow to be chiefly useful on. \nstrong tenacious clay soils ; and although it be true that the mineral earths in \nthe composition of the soil, attract no new principles of fertility from the air, \nthere are inferences deducible from his own doctrines which seem to recom- \nmend fallows for such soils. Waving the destruction of weeds, which can be \nmore effectually accomplished by fallow, than by any drilled or green crop, \nwe observe, 1st, That by exposing soil in large clods, to the action of the \nsun\'s rays, in spring and summer, it is heated to 120\'\' of Fahrenheit, and often \n\xe2\x96\xa0much more. By this its moisture is exhaled, and the clay comes somewhat to \nresemble that described by our author, which had been burnt with fire. It \nbecomes more brittle, and less apt to cohere with subsequent moisture. Hence, \nthe oftener our carse soils are treated with fallow, the more friable they be- \ncome. 2d, When our author pronounced this severe censure upon fallows, \nhe seems to have forgotten what he so often states in the course of his work, \nthat after all the soluble matter in a Soil is exhausted by cropping, there still \nremains much charcoal, the remains of woody fibre ; that this charcoal im- \nbibes a large proportion of oxygen when the air has access to it, but that it \nI\'emains inert in the soil, unless a new fermentation be excited in it, by various \nmeans which he describes. Now, in clay soils this charcoal is effectually ex- \ncluded from imbibing oxygen from the air, but is brought into a condition to \ndo so by fallowing. The effect of this, and of its imbibing moisture, is its \ngradual conversion into carbonic acid, and carburetted hydrogen, for the nou- \nrishment of plants. Accordingly, esperjencetl farmer* have assured us, tfaa\'. \n\n\n\n86 ADDITIONAL, NCKfES. \n\nthey have known kuid that liad been long manured, and aftenvards exhausted \nby cropping, have its fertility more restored by a fallow than if it had re- \nceived a full dose of p\\itrescent manure. Their experience may be accounted \nfor by data furnished by our author; and we are sorry that, in this case, \nhis conclusions seem to be in direct opposition to his premises. We so \nfar, Lowever, agree with him, that tallows are sometimes too often repeated, \nespecially on sandy soils, where drilled crops may, in general, serve their \npurpose ; but on cohesive soils we hold them to be occasionally indispensable." \nFarmer\'s Jila^asine, No. LXIV. (dated 6 Nov. 1815.) p. 48y. \n\nP. 50. It is decomposed, &c.] \xe2\x80\x94 The sulphuric acid in gypsum will also com- \nbine with ammonia. Manufacturei*s of sal ammoniac liave availed them- \nselves cf this, afterwards disengaging the ammonia with muriatic acid. \nThis strengthens the motives for trying with gypsum composts containing \nanimal filaments. Composts, rightly proportioned, are in general moi-e effi- \ncacious than any simple"" manures. \n\nP. 76. The fijih argimxent is entirely practical, and the authority adduced in \nits support one of the highest.] \xe2\x80\x94 The Author of the Lectures might have cited \nanotlier great name, as an advocate for expending putrescible manure in \na fresh state. From the \' Hints on Agricultural Subjects,\' (by .1. C. Curwen, \nM. P. of Workington Hall, Cumberland, Esq. 2d edit. London, 1809,) it may \nbe collected, that tiie practice at the Schoose Farm was shaped upon this \nprinciple, but with many capital divergencies from the broad .and indiscrimi- \nnate track which owes its ease and simplicity to the nature of mere specula- \nlion. \n\n" 1 should say, . . . bury the manure as deep as possible, and then sow the \ntui\'nips directly on the manure, leaving twenty-four Inches between the rows : \nthis will afford ample room for the plough to work, v/hioh will not only \nadmit complete cleaning, but in the operation furnish that degi-ee of nourish- \nment to the turnip, which in very dry seasons would be highly serviceable, \nand contribute greatly to (he weight of the crop " Hints, p. 221. \n\n" This method would also permit of fresh stable-litter being made use of, \nwithout the necessity of its undergoing that degree of fermentation which \nreduces it at least one-third in bulk ; and, in my opinioji, still more in effi- \ncacy. . . I have taken great care in having horse and cow dung mixed in equal \nquantities, and the muck-heajis formed into pyramidal shapes, so as to admit \nof their being easily covered with earth, whicli is collected for this purpose \nfrom head-lands and ditclies. This method prevents the evaporation ; and \nthe gas imbibed with tlie earth makes it equally valuable with the dung. The \nmaking what is called manure pies is a common practice in Ireland. It serves \n\xc2\xabTeatly to increase the quantity, which must always be acceptable to the far- \nmer." Hints, ^.222. \n\nMr. Curwen\'s method of applying manure in the field is but part of a sys- \ntem ; therefore, before giving that method, it will be ))roper to state, thai his \nfirst principle for bringing foul land into good tilth, and for superseding a na- \nked fallow, by the i-elief of alternate green crops, is, \xe2\x80\x94 to leave such a space \nbetween the stitches of the green crops as will admit of working both with \nthe plough :ind hoe throughout the season -, a space double to what is com- \nmonly allowed. He holds, that by constantly turning the vacancies between \nthe rows or beds, in every direction, he can in dry weather procure for the \n])lants something like a compensation for rain, in the evaporation of m.oisture \nfrom the earth. " The first day\'s exhalation from ploughincr is in the propor- \ntion of 950lf)s of water per hour front an acre. Tne evaporation decreases on \nthe second day a third part, and continues to diminish for three or four days \naccording to the lieat of the weather, when it entirely ceases ; and is again \nrenewcil by fresh ploughing." Hints, pp 211, 212. \n\n" A field of cabbages were this year set on a very strong stiff clay, which \nprevious to their being planted was in high tilth. The severe drought which \nsucceeded the rains that fell soon after setting, baked the ground perfectly \nhard. The plants made little or no progress; they were seen by a friend of \nmine, on Monday the 26th of May, as I was commencing the breaking of th(^ \n\n\n\nADDITIONAL NOTES. 87 \n\nground with the ploughs. I\'hey were worked for the whole week. On the \nbaturday they were seen again by the same gentleman, and he could scarcely \nbe persuaded tiiey were tlie same plants The week had been very dry, with a \nhot sun, and strong norlii-east wmds. Tlie crop of last year was allowed to have \nbeen u very extraordmary one, and weighed thirty-five tons and a half jjcv \nacre. Some of the cabbages were fifty-live pounds ; they had only fourteen \ntons of manure upon the acre. My second principle is, to bury the dung as \ndeep as possible, in order to retard the evaporation, and keep the heat in tlie \nground, by preventing tlie atmosphere from acting upon it. It is a point to be \nparticularly attended to, that the manure should be kept quite dry, w hich is \ndone by having a deep trench in tUe centre of tiie sijuce between tlie rows. \nBy these two combined principles, 1 expect 1 sliall succeed in obtaining equal \ncrops, though but one lialf, and in some instances, only a third of my ground \nis occupi\'id. To pronounce decidedly tiiat this will be the case would require \nfurtiier experience than 1 can prc\'cnd to boast of. So many circumstances \nougli! to be taken into consideration in every expei\'iment, that many trials \nmust be had before it can be pronovinced altogetlier successful. 1 have the \ntesiiniony of a very meritorious agrlouliurist, wlio iias made several experi- \nments upon this plan in garden husbandry, and wlio states the most favourable \nresult. \'I\'lie gentleman I allude to is the Itevcrend E. lilkrton, of Colston, \nnear Ulverstone. To such as iiave no option, hke myself, but are obliged to \nset their potatoes on wet ground, the plan 1 have followed has in one parti- \ncular been found to answer a most admirable purj)ose. it keeps the potatoes \nso perfectly dry, that in tliis unparalleled year of wet, where in most dry \ngrounds tlie loss by decayed potatoes has been very great, 1 have had no loss \nwhatever. 1 cannot boast of the weiglit of my crop, but indeed it was not to \nbe expected, being set a month later than the usual time, and the vegetation \ndestroyed by the frost in the very beginning of September, which is a month \nbelbre what is common. I am by no means discouraged or dubious of the prin- \nciple on wliich it was undertaken ; and I hope to give il -i very fair trial." \nMnts, pp. 213, 214. \n\n" Dung, and .ill the animal mixtures, 1 bury as deep as possible, taking care \nlliat they shall he deep. Lime, (the little 1 use being solely in compost,) \nschistus, . . . sand, &c. are used for top-dressings." /{iiUs^ p. ^22. " 1 am \nstrongly inclined to believe, that where the ground is laid dry, that manure \ncan scared)\' be deposited too deep , by so doing the evaporation is retarded, \nand consequently, the manure continues for a greater length of time to fui-- \nnish nourishment to the crop." HhUs, p. 26S. \n\n" The experiments I have made tend to establish the double advantage of \nwell cleaning and working the ground. First, as it frees the land from weeds ; \nand secondly, as it conduces to the growth of the crop. It aftbrds likewise a \nvery strong demonstration in favour of using the manure in its freshest state, \nby which not only the great usual expense of making dunghills will be saved, \nbut the manure made to extend to the improvement of a third more land. \n\n" Most of the farm 1 occupy was in that state of foulness as to require, ac- \ncording to genei-cal practice and opinion, a succession of fallows to clean it. Be- \ning unwilling to adopt a system which is attended with such loss, 1 determined \nto attempt to clean a part of it by green crops, and for such purpose to allow \na much greater distance between tlie stitches than Isad ever been in practice. \nMy first experiment on this plan was made on a crop of cabbages ; they were \nplanted in a quincunx form, allowing four feet and a half between each piant, \nin order to allow room for the plough to wn-k in all directions. 1 adopted, tliis \nplan of field husbandry, as alfording the greatest fiicility in cleaning the crop, \nthough I believe it was never before practised. Two thousand three hundred \nand fifty plants were set per acre (eight thousand is not unusual in the com- \nmon method,) and each plant had, by computation, an allowance of a stone of \nmanure, or less than fourteen tons per acre ; though the common quantity is \ngenerally from tliirty to forty tons per acre. The manure was deposited as \n(leep as the ]d(Migh could penetrate, drawn by four horses, and the plant set \ndirectl)\'^ above it. \n\n" The plough and harrow, constructed to work betwixt the rows, were con- \nstantly employed during the summer, and the ground was as completely freerl \n\n\n\n88 ABBITIONAL NOTES. \n\nfrom weeds as it could have \'"een by a naked t;illow. Tlie very surprising- \nweight of my crop, whioli ia October was thh"ty-five tons and a half per acre, \nand many of the cabbages fifty-five pounds each, were matter of surprii^e to all \nwho saw them, as well as to me ; and I could assign no satisfactory reason for \nthe fact. The quahty of tlie land was very indift\'erent, being a poor cold clay, \n\xe2\x80\x94the manure was very deficient of the usual quantity, \xe2\x80\x94 the plants when set by \nno means good, \xe2\x80\x94 in short, there was nothing to justify tlie expectation of even \na tolerable crop. 1 did not find any thing in the accounts from cultivators of \ncabbages to afford me a solution of my difficulties, or any clue to explain it. \nBy mere accident 1 met with the Bishop of Landatl\'s experiment, ascertaining \nthe great evajioration from the earth, as related in his admirable Treatise on \nChymistry ; singular as it may appear, this very uiteresling" experiment had re- \nmained for thirty years without any practical interences being drawn from it \napplicable to agriculture. It apj^eared to me highly probable, that the rapid \nadvance in growth made after the hoemg of drilled grain, was attributable to \nthe absorption of the evaporation produced from the earth, and was the cause \nof the growth of my Cabbages. With great impatience and anxiety, as I had \nthe honour to inform you last year, I looked forward to tiie ensuing season to \nafford me an opportunity of continuing my experiment. I had long been a \nstrenuous advocate for deep burying of manure, tliough my sentiments rested \nchiefly on opinion ; this appeared to open a field for incontestable proofs of its \nadvantage. My cabbages were last year planted on the same plan as the for- \nmer year. Fortunately 1 extended the same principle to my potatoes, whicli \nI was obliged to set on wet strong ground, from want of a choice of land. My \nannual quantity of potato ground is from sixty to seventy acres. They were \nset in beds three feet long, and two feet broad, leaving four feet and a half be- \ntween each bed lengthways, and; hree feet endways. On eacli acre there \nwere 1230 beds, and 615(J sets, or five to each bed, viz. one at each corner, \nand one in the middle. I\'he sets of potatoes, when planted according to the \nusual most approved practice, in three feet stitches, and nine inches apart, \namount to about twenty thousand. In the present, and indeed in all seasons \nwhen potatoes are scarce, the savmg in planting is a considerable object A \ngreat advantage also arises in being able to keep the potatoes and manure from \nwet. In the late uncommonly wet season I sustained little or no loss in my \nmode, which was not the case in many of the driest grounds. This plan unites \nhand hoeing with horse culture, and will be found serviceable in wet soils. \n\n" The lateness of planting, together with the premature frosts, prevented \nmy forming a fair judgment as to the quantity per acre which might be obtain- \ned by this method. My view in fixing upon this plan was, to enable me to \njudge of the effects of evapor.ition, by being able to continue my operations \nfor a longer period. I have no doubt but that in common seasons, notwith- \nstanding the increased distance, the whole ground would be covered. \n\n\' " My experiments on cabbages this season, commenced by planting them \nearly in April. From the rain which fell subsequently, and continued till the \nbeginning of .May, succeeded by severe east winds, the earth became so hard \nand baked, that the plants had made very little progress. \n\n" In the first week in June the ploughs were set to work : as they started, \nMr. Ponsonby, of Hail Hall, was .present, and saw the crop ; it was with diffi- \nculty that the ground was first broken, but by the end of the week it was \nbrought into fine tilth. Notwithstanding the whole week had been dry, with \na strong sun antl severe east wind, yet such was the progress in growth of \nthe cabbage, that when seen again by that gentleman on the Saturday, he coidd \nscarce be persuaded they were the same plants. \n\n" During these operations I had been making constant experiments with \nglasses, contrived for the purpose, to ascertain the quantity of evaporation from \nthe land, which I found to amount, on the fresh ploughed ground, to nine hun- \ndred and fifty pounds per hour on the surface of a statute acre, whilst on the \nground unbroken, though the glass stood repeatedly for two hours at a time, \nthere was not the least cloud upon it which proved that no moisture then \narose from the earth. \n\n" The evaporation from the ploughed land was found to decrease rapidly af- \nI tei" the fil\'bt and second day, and ceased after five or six days, depending ou \n\n\n\nADDITIONAL NOTES. \n\n\n\n89 \n\n\n\n\\We; wind and sun. These experiments were carried on for many inontlis. Af\xc2\xab \nter July the evaporation decreased, yvliich proves tliut though the heat of the \natmosphere be equal, the air is not so dense. The evaporation, after the most \nabundant rains, was not advanced beyond what tlie earth afforded on being \nfresh turnevl up. The rapid grow th of my potatoes corresponded perfc-ctly \nwith the previous exjjerinicnts ; and their growth in dry weather visibly ex- \nceeded that of other crops where tiie earth was not stirred." Hints, pp. \n269 . . 274. \n\n" The evaporation from dang is five times as mucli as from earth, and is \nequal on the surface of an acre to 50Uu pounds per hour. By making use of \ndung in its freshest state, the farmer may extend his cropping to one-third \nmore land with the same quanti:y of manure. It is with regret that 1 have \nviewed in many parts of the kingdom the quantity of manure wliich is exposed \non the surface, and tends to no good. I am strongly of opinion, that in all\' \nlight soils, if the manure was buried in trenches as I propose, and the turnips \nsowed above it, that more abundant crops would be procured. By cleaning \nwith the plough, great advantage would be derived to the crop, from the eva- \nporation yielded by the eai th. Hot manure might also be used. By fermenta- \ntion dung is reduced to one half its bulk, and its (quality reduced in a much \ngreater proportion. The manure now con)monly taken for one acre of broad- \ncast, would if deposited whilst hot in drills, answer for four acres, and the crop \nproduced be much more." Jtints, p. 275. \n\nThese extracts embrace three important things : 1. Grekn chops with wide \n\nINTEIIVALS. 2. TaV. APPLICATION OF TUTRESCIBLE MAXUUE IN A FUESH STATE. 3. \n\nThe pnoposEi) extension ot this puactice to light soils. \n\nIn relatiori to the first head, the copious evaporation of moisture from new- \nly turned earth is an important disc overy. The wide inttrvals in the green \ncrops are to provide for its free application. The iutention is judicious : but \nin leaving intervals wide enough for a plough to work, tlie sacrifice of area \nmay outweigh the benefit, especially if the plants are not capable of reaching \na size in proportion to the space between them. The large field cabbages are \nperhaps most likely to aflTord a compensation in weight, in what degree the \nusual field crops would be thus diminished is highly requisite to be computed; \nfor if the produce from an acre is diminished every alternate year in a mate- \nmi proportion, the sacrifice in even or eight years may be equal to one na- \nked fallow in the same time, or may exceed it. VViien potatoes are planted^ \nJn the manner above described, \n\n\n\n3 feet by 2 \n\n\n\nIntervals of four feet and a half. \n\n\n\n3 feet by 2 \n\n\n\nThe unplanted ground is as 11 to 2; and can it be expected that the roots \nwill send out runners halfway across the wide intervals .\'\' or that the weight of \ncrop can sustain a competition with one raised from closer beds ? We" may \nfionclude that further experiments produced the conviction that such green \nfallows are on the average unprofitable ; for at the date of the letter cited in \nthe preceding treatise, (p. 31. n.) The President of the Workington Agncul- \ntural Society had become reconciled to a summer fallow in rotation with white \ncrops, on a clay soil. But the history of experimental farming is a history of \nrevolutions in which practices which seem to be the very same are alternately \nabandoned and resumed \xe2\x80\x94 seem to be, but they arc not, the very same ; lor the \ncu\'cumstances of positive knowledge are different by the a<lvancement of a \nstage, and the preponderating obstacle which last turned the scale, is removed \nfcy a new contrivance. Thus, a clay soil can be rendered fit for green crops \nby a top dressing of clay ashes; (^Treatise, p. 54) and whether the system of \n\nM \n\n\n\n90 ADDITIONAL NOTES. \n\nsummer fallowing\' is cnlirtly superseded by this resource, will depend sow \nupon a fair comparison ofllie expense and benefits found to atteml botb courses,. \nTlie letter of Mr. (Un-wcn to Air, Dempster, (adverted to in the preceding \ntreatise, j). 55. r.) has these two pass:i}^-es. " ( conceive that 1 am justified in \nanticipating a rapid increase of j^reen crojjs, the means of producing them be- \ning now within the reach of every one." \xe2\x80\x94 " 1 do not think I am too sanguine \nin viewing tlie general adoption of the system of surface soil and clay-burn- \ning, as dkely to be the most impoitaut discovery for the interests of agricul- \nture, that lias ocxurred since the introduction of the turnip into Norfolk by \nLord Townscnd." \n\nThe second subject wliieh wc are stimuTated to consider anew by Mr. Cur- \nwen\'s f/i/iix, is, The application of putrescible manure In a fresh state. It is \nplain tiiiit all the ins;a:ices, above collected, of this appFication relate only to \n:irable land. \n\nNow, if we ad* ert to the local climate, and the soil, at the Schoose Farm, \nwe may see caues wliysuch a practice, as part of a system, may confer partial \nbenefits ; and why its positive defects may be compensated, its disadvantages \ncour.cractcd. 1. i\'he climate is moist: "42 inches of rain fall in the twelve \nmonths, whilst in Norfolk ihey have but 22." (Hints, p. 211.) 2. The sod is \n"a stiff loam, partaking in a great measure of clay." (p. 262) 3. Deep \nplougliing for tlie winter tjillow is practiced there ; the furrow at the first: \nplougliuig for a green crop is described as from 11 to 14 inches deep, (p- 211.) \nThe .\\uthor of the JJi?its notices, however, the objections which tiie advoca:es \nof other systems have made to this part of his : " More diversity of opinion \nis fomid to exist as to deep and shallow ploughing\' than might be expected. I \nshould deem .shallow ploughing four inches; niediiun, ^ix; deep, nine: but \nevery six years I siiotdd advist- making tiie winter fallow twelve ; 1 have found \nit in\\ari:ibly to answer, and it is with satisfaction 1 see it becoming* very gene- \nral in tlie cou!ity of Ciunberland." (p. 237.) \n\nTo, connect these circtimstances. \xe2\x80\x94 If strawy litter is buried in a deep fur- \nrow under a drilled ridge, the channel thus created will at least operate as a \ndrain ; which must be a benefit on a clay soil in a moist climate. Supposing \nthe fresh litter, dung, or animal refuse lying deep from the surface, not to be \ndecomposed till tlie following season, yet if there be already in tlie soil suffi- \ncient aliment of any kind for the plants the first year, the farmer will not be \ndi-sappointed at h.irvest time : me:inwhile there is a |)ri)vislon of manure for \nthe following year; and the same course m;iy be annually repeated with a di- \nminished haziutl of starving tlie crop. Supposing, on the contrary, the fresh \nmanure to decompose in that silu;ition, the first season, the deep burying of \nit leaves a l.iyer of earth for the growing roots : thus the banefid contact \nof hot dung," putrefying vegetables, and rank animal fluids, will be eluded. \nStid let all the accidents be fortunate, some losses and waste must attend this \nway of de]iositing manure, either from fibrous matter getting too deep to be \nacted u])on by the atmosphere, or by rich fluids irrecoverably sinking into the \nsubsoil beyond the .attraction of annual crops. \n\nAs to grass-lands, the practice .it the Schoose Farm appears to be, to manure \nthese with imputrescible substances, in a shape for sinking presently into the \nsurface ; such as coal-ashes\xe2\x80\x94 streetrakings\xe2\x80\x94 sea-sand \xe2\x80\x94 and schistus (coal-slate) \npreviously pulverized by mixture with caustic lime, six parts to one of lime. \nIn this, there is nothing to coiuitenance the project of spreading fresh litter \non pasture It ma}\' be observed, that although all these articles must improve a \nsoil of clay, yet only the street rakings can have niiicii jjower as containing \nmanure fbr a ])lant to consume. If clover and rye grass, under treatment which \ndecidedly improves the texture of the soil, now and then turn out a bad crop, \nit niav be attributed to a deficiency of aliment ; plants cannot get plump on a \ngood lodging, if poorly fed. The least rapacious feeders have some ap- \npetite. \n\nThiiilly, our exti\'acts from the Hints contain this important suggestion : " I \nam strongly of opinion, thiU in all light soils, if the manure was buried in \ntrenches as I jM\'opose, and the turnips sowed above it, tliat more abundant \ncrops w oulil be produced." The agTiculturisl who combines knowledge with \ninvention, enlerpnze with experience, liberal communication wltlx vigilant in- \n\n\n\nADDITIONAL NOTES. 91 \n\n*[viiiy, and candidly declares tlie results of his own experiments, will necessa- \nrily frame a system of far.O\'ng^ liolli benclicial to liis own estate, and that may \nbe transf<.-rrcfl witli benefit to lanls similar to tliose which lie has long- mana- \nged. If he propijse to tiunsf-r the system to an opposite sort of soil, a mere \nopinion from sucii an autnority, strong\'ly expressed, may mislead. Practical men. \nwJK) have tried tlie application of loiij"- littery diin}^, and seen it extensively \ntried, on light sous, pronounce decidedly that it is inferior in cificacy to weli \nfermented manure. With rej^ard to t!ie soil itself, the want of <luc tenacity, \none of the inconveniences of lij^ht sandy land, i^ increased by loose litter, so \nthat the seeds are more exposed to be Ijlovvn out, or the plants unrooted. As \nto tiie crop, it consults the hab.t of hardly ^ny jjlaiit but the potato ; and even \nfor tiiis the long litter should be cither slji;lilly fermented, or but ju)*t covered, \nwitli earth, that air, heat, and moisture, may help it to decompose. \n\nP. 83. 7\'o disregard the loss nf trasrons and vo\'atile matters, both from thf dmif. \n\nhill, and from the surface of the land ,\xe2\x96\xa0 and to estimate it rutlier us a henrfit.] \n\nOne of lln\' principal fjaseous matters cscapinj,\' from dunghills and fallows is. \nammonia or volatile alkali. The Author of tl^e elements dwells miicii on the \nmagnitude of this loss. But what is Ammonia ? And is it to be valued lor its \ncon\'rjbutioiis to the loots o\' the living plants.-\' or for its cliemical agency on \nvegetable, animal, aiul mineral substances, lodged in tiie manure or in the soil.^ \nAmmonia is composed of nitrog\'. n (or azote) and hydrogen, both gascs; the \nfirst an abounding element of common air; the .second the basis of water, and \nthough not pr\' perly a < onstituent of ilie atmosphere, frequently suspended in \nit; say eigiit parts of azote to two of hydrogen ; for the proportions given by \nchemists vi\'.ry. Sir II. Davy has also separated from ammonia a .substance that \nwill unite with mercury \\without destroying its n.etallic lustre. It may help us \nto form a clearer notion of ammonia for pracuea! purposes, merely to trace \nsome of the methods of procuring ic artiiicially. The Egyptians obtained what \nPliny calls sal ammoniac by .sublimation from t^ie urine of camels ; and in mo- \ndern times, the sal ammoniac of commerce, by sublimation trom fuel formed of \nthe dried dung of cattle which had been fed on a spring grass, described as \nsomewhat like clover. The European chemi.sts have successively extracted \nt, by varied processes, from bones divested of fat\xe2\x80\x94 fiom urine \xe2\x80\x94 from promis- \ncuous animal solids \xe2\x80\x94 from liai;-, fur, feathers \xe2\x80\x94 peltry dressed with the hair \n\nburnt in furnaces, and sublimed ; also from soot. This pungent aroma is a1- \nwa\\\'. generated by the combustion of animal iilament, especially those hollow \ntubes and fii)res whicli ov.e their consistency to a portion of lime It occurs \nconstantly and .bundiintly in animal matt r ; wh le pure vegetable substances \n(those which have not been mixed witii .Hnimal matter) do not invarlablv con- \ntain it, and such as give it out on distillation afford minute or evanescent quan- \nv.ities. The fruit of the Green (.gooseberry {KHjch (jrossuhmn) yields it on \nanalysis; also the pollen of tulips, 1 pi-rt in 2(J. From the higlily volatile na- \nture of ammonia, tli \xe2\x80\xa2 plants in wliich it is found may e.isily derive it from the \natmos|)here ; nor can its presence in the soil be considered necessary to the \ngrowth of any plant, as aliment. \n\nIs volatile alkali to be valued for its chemical agency in a dunghill, or other \nheap of putrescible manure ? As man\\ auima\' and vegetable substances, and \nsome fo.ssil.salfs, can be decomjiosid by this alkali, its presence in dmig-heaps \nin fallows, and in all grounds preparing for crops, must be esteemed higidy \nuseful. Hut then its utility would be obslrucied, not promoted, bv arresting \nits free action. To attempt to detain it by avoiding\' fermentation is to prevent \nits developement, if not its formation. Ammonia in action will decompose \nthe crystals of salts of iron. \'I\'hus, if peat containing that pernicious com- \npound be laid upon a putrefying dungliill, the peat, as soon as it has been tho- \nroughly steamed with ammal alkali as well as fermented, will be rectified no \nless than if it had been mixed with lime. .So decayed tree-leaves, or wood \ncontaining tannin, will be sooner fitte<l for manure than if fermented alone. In \nall this we find additional motives to cover a fermenting dunghill with a case \nof earth, or compost co .ta\'ning dry vegetable matter, tliatthe fugitive vapours \nmay be intercepted before their virtue is exhausted. \n\nTo detain ammonia in the bosom of land, except in the shape of a salt, mav \n\n\n\n92 . ADDITIONAL NOTES. \n\nrequire a talisman, like that which confined the genie in a coppervessel. From \nthe number ot" animal substances, inchulinp;\' dungs, which evolve it, when ci- \ntlicr burnt, or highly fermented, or mixed with caustic lime, it may be expect- \ned to be redundant rather than deficient in most cultivateil soils ; and the ex- \nperiments noticed in p. 5", shew that a small quantity of any salt of ammonia \nmust be diluted to great weakness, by mixture with water, not to be in excess., \nI believe those soils in which sal ammoniac is found native, are not very fer- \ntile ; but nothing positive can be stateil on this head, until the travellers in \ncountries which atlbrd it, give us more particular information. Muriate of am- \nmonia has been found native in some of the mountains of Bucharia, and Thi- \nbet ; and in the waters of some lakes in Tuscany. It occurs also in small \nquaiUities near the neighboui hood of some volcanoes. The sal ammoniac of \nPliny has been found in a fossil state, below the sand, in a district of Cyrenai- \nca, the modern Desert of Karca. \n\nThe agency of free unconfined ammonia must be of unqualified benefit to \nfallow land, as tar as dormant vegetable matter, or other substances of which \nthe decomposition is desirable, lie in the way to intercept this stimulating va- \npoiu\' ; nor is it easy to imagine a case of exception previously to putting in \nthe ])lants. Although in a glebe which is freely turned and exposed to the \natmospliere, the volatile alkali, latent in animal m^unires before fermentation, \nhas a tendency to dissipate into thin air, why should we seek to obstruct its \nspontaneous (light, at the expense of losing many cei-tain advantages, by lea- \nving the surface bound and indurated for want of tillage ? Could we seal up \nthe pores of the earth, two powerful considerations might reconcile us to the \nliberation of this alkali from the bosom of a fallow, before the plants are put \nin. On the one hand, as far as any substance is active in decomposing vegeta- \nble niatter, its presence in a copious degree cannot be accounted serviceable \nto the roots of growing plants. It is true that most annual plants are Jess sus- \nceptible of injury from the contact of putrifying vegetable matter than slirubs \njmd trees; perhaps because in a small plant, of which every part is growing, \nthe principle of life is stronger ; whereas the hard roots of a tree contain wood \nthat has done growing, and is therefore unable to resist the contagion of a rot- \nling substance. Still even summer annuals or tender exotics are injured by \nthe steams of recent dung; and in the pivparation of stable dung for hot-beds, \nit is found indispensable to let the first fermentation expend its strength, un-. \ntil it has come to what gardeners call a sweet heat .- meanwhile, liberated am- \nmoniac goes ofl" in clouds of vapour, betraying itself by an oflensive smell : in \nthis the object commonly proposed is merelv to expend a furious heat; but the \nJoss of ammonia is an inseparable effect, ami no doubt of equal benefit The \ntime which elapses before common weeds will grow on a dunghill is anothei" \nindication not to be disregarded : it seems alone a confutation of the doctrine \nthat fresh putrescible manure is at once food for plants. On the other hand^ \nit is reasonable to conclude, that, whatever plants are constituted for receiving \ninto their growing substance, a portion of ammonia can separate from air and \nfrom water sufficient supplies of its two elements, and appropriate them by \ntlie admirable provisions of Nature\'s chemistry. \n\nIn regiird to the soil, it does not seem to be m.aking the most of manures con- \ntaining ammonia, to \\ny them on the surface of fallow land. If they ju-e turn- \ned in at a slight depth, so as not to obstruct the reijuired fermentation, the am- \nmonia will steam many fragments of vegetable, anim.il, and fossil remains, be- \nfore it e.scapes through the covering of eai\'th. 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V \n\n\n\nx.^^ \n\n\n\n\n\n\n\n\n\nv \n\n\n\n\n\n\n\n\n\n&\xe2\x96\xa0 \n\n\n\n\n\n\n^ 9<. \n\n\n\nV \n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\' \\.^ ^^^\'\'^-Y;^\'\\.<s^ \n\n\n\n\n\n\n\'%, .0.^ \n\n\n\n.v,^ Cj \n\n\n\n\n\n\n^^^. \n\n\n\n5-^ \n\n\n\n\n\n\n'