i%< .^ «tv ''>-] ■«J.- * :-m: ^y ,^"<> >v "tr 4^ ^GJt f^ ^^(i ^^r'^ Digitized by tine Internet Archive in 2007 with funding from IVIicrosoft Corporation http://www.archive.org/details/agriculturalpampOOvoelrich r ' ^ t ^CuttuA/U f^H^uAMriJ^ Vq Analysis of the Anthracite of the Calton Hill^ Edinburgh. By Dr A. IVoelcker, Professor of Chemistry in the Agricultural College, Cirencester. * {From the Edinburgh New Philosophical Journal for April 1850.) We are in possession of analyses of anthracite from seve- ral localities, and we have learned by them, that the composi- tion of this mineral, like that of coal, varies very much ac- cording to the locality where it is found ; so that there are scarcely two localities which furnish anthracite of exactly the same composition. All samples of anthracite which have been analysed, have been found to contain carbon, hydrogen, oxygen, nitrogen, and more or less inorganic matter, as well as sulphur (at least where it has been looked for), in a proportion which dif- fers but slightly from that in which it occurs in common coal. Generally speaking, the per-centage of carbon is larger in anthracite than in common coal, whilst hydrogen predo- minates in the latter; and we find, likewise, _that the more the anthracitic character of a sample is pronounced, the greater is the deviation from the composition of common coal. On the other hand, the more an anthracite resembles common coal in its physical character, the closer is the ap- proximation to the latter in chemical composition. The sul- phur which has been found in every specimen of anthracite in which it has been sought for, is generally considered as ex isting in it as well as in coal, in combination with iron, as iron pyrites, but the subjoined results shew that the sulphur found in anthracite does not always occur in the form of iron pyrites, but is, in part at least, in combination with the organic elements of the mineral. In the following ana- lyses the greatest care was ta^en to deprive the anthracite * Read before the Royal Society of Edinburgh, 4th March 1850. 2 Dr A. Voelcker on the of any hygrpscopic water, by keeping it finely powdered in a glass tube, at a temperature of about 230° F., and passing over it a current of dry air for several hours. The per-centage of carbon was ascertained by burning from three to four grains with a mixture of oxide of copper and oxide of lead, and the simultaneous application of oxygen gas, in order to secure complete combustion of the carbon. The oxygen, for that purpose, was disengaged from chlorate of potash, mixed with pure oxide of copper, and placed at the closed end of the combustion-tube. A mixture of the oxides of eopper and lead possesses the advantage over pure oxide of copper, of being much less hygroscopic ; for that reason it is peculiarly adapted for combustions in which the exact amount of hydrogen is to be ascertained. The nitrogen was deter- mined according to Will and Varrentrapp's method, by heat- ing the finely-powdered anthracite with soda-lime in the usual way. For the determination of ash about 10 grains were burned in a platina capsule. The ash was coloured red by oxide of iron. The proportion of sulphur was ascertained by introducing, into a red-hot crucible, a mixture of anthracite with carbonate of soda and nitre, in small quantities at a time, and heating the whole afterwards a little more strongly. The resulting fused and perfectly white mass was dissolved in water, super- saturated with hydrochloric acid, and the sulphuric acid then precipitated with chloride of barium. According to the different results obtained, the composition of the anthracite of the Calton Hill is : — Car'bon = 91-23 Hydrogen = 2-91 Nitrogen = 0-59 Oxygen = 1-26 Sulphur = 2-96 Ash = 105 100-00 For comparison with this analysis, I subjoin a few analyses of anthracite from different localities. Anthracile of the Calton Hill. 1 fl u 1 f ^ d X o W o ^ < From Lamure, Isere Depart- " ment, according to Jacque- lin (Annal. de Chimie et 89-77 1-67 3-63 0-36 4.-51 de Phys. Ixxiv., 200), From Sabl^, Sarthe Depart- ) ment, . . . j 87-22 2-49 1-08 2-31 6-90 From Vizille, Isere Depart- ment, . . . , 9409 1-85 ••• 2-85 1-90 From another locality in Isdre " Department, 94-00 1-49 0-58 4-00 Anthracite from Pembroke- ' shire, according to Schaf- hautl, Lond. & Edin. PhH. 94-100 2-390 1-336 0-874 1-300 Mag. xvii., 215, From Coalbrook in Carmar- ) thenshire, ... J 90-58 3-60 3-81 0-29 1-72 Anthracite from Wales, . 91-44 3-46 2-58 0-21 Sulphur. 1-52 0-79 The last analysis is taken from Sir Henry de la Beehe and Dr L. Play fair's Coal Report, the others from Hausmann's Mineralogy. The most remarkable peculiarity of the anthracite of the Calton Hill is the comparatively large quantity of sulphur which it contains. By far the greater portion of this sul- phur must have been in combination with the organic ele- ments of anthracite ; for, even supposing the whole of the ash to consist of oxide of iron, the quantity of iron would still be too small to combine with all the sulphur. I am not aware that attention has been drawn to the fact of sulphur occurring in anthracite in organic combination ; but a little consideration, I think, will shew that such a compound may exist in nature, as we can prepare artificially, similar com- binations. It is well known that, in preparing sulphide of carbon, by passing sulphur in vapour over red-hot charcoal, the charcoal which remains in the vessel in which the experi- ment has been made, contains sulphur in such a state of com- 4 . Dr A. Voelcker on the bination that it cannot be expelled by heat, provided the air be excluded. According to Prout, a similar combination of sulphur with carbon is easily obtained by washing on a filter common gunpowder with water till all the nitre is removed, and heating the insoluble part of the gunpowder in a retort ; some of the sulphur will distil off, and part of it remain in combination with the charcoal in the retort. This sulphur, and the nitrogen, which is always found in anthracite, tes- tify in favour of the vegetable origin of this mineral, and appear to support the opinion of those who regard it as the carbon-remains of organized bodies of the oldest formation, in which the process of carbonification has proceeded still farther than in coals. At all events, the above analysis furnishes an additional proof of the erroneous notion of former naturalists, who re- garded anthracite as primitive carbon. This notion, pro- bably, has arisen from the fact, that anthracite, exposed to a red heat, produces no hydrocarbons like coals, and that it re- sembles carbon likewise, inasmuch as it is consumed by fire almost entirely, leaving but a small proportion of mineral matter in the form of ash behind. The loss incurred by incineration of anthracite was generally calculated as carbon by chemists, before the present methods of analysing organic substances were known. Some observers, however, inferred that water existed in a state of chemical combination in an- thracite, as appears from a statement of Lampadius, in an able paper on the Anthracite of Schonfeld in Saxony, which appeared in Erdmann's Journal der Chemie, 1835, 4th Bd., p. 393. By a careful observer like Lampadius, the presence of sulphur and nitrogen in anthracite was not overlooked. He likewise examined all the products of its dry distillation, and obtained, besides water, a mixture of gases, which con- sisted of carbonic acid, carburetted hydrogen, carbonic oxide, and nitrogen. Similar results were obtained on analysis of two varieties of anthracite from North America, which Professor Brei- thaupt of Freiberg procured for him. These samples, from Manchchunk in North America, and from Rhode Island, are described by Professor Breithaupt as remarkably fine an- Anthracite of the Calton Hill. 5 thracite. The imperfections of the analytical methods at that time, however, led Lampadius to draw false conclusions from his analytical results, and induced him to consider all anthracites as hydrates ; but we know at present that the hydrogen and oxygen in anthracite are not united as water. Though mistaken in his quantitative analyses, Lampadius, nevertheless, has the credit of having pointed out the quali- tative composition of several varieties of anthracite more ac- curately than any chemist who examined this mineral before him. In all samples he detected carbon, oxygen, hydrogen, nitrogen, and sulphur, besides the ash, or the same substances which were found to enter into the composition of the anthra- cite of the Calton Hill. [From the Annals and M agazlne of Natural HisTORv/or Mar. 1850.} XVII. — On the Watery Secretion of the Leaves and Stems of the Ice-plant (Mesembryanthemum crystallinum^ L,). By Dr. Augustus Voelcker, Prof, of Chemistry Royal Agricult. Col- lege, Cirencester*. A FEW months ago I had the pleasure of communicating to the Botanical Society of Edinburgh the results of an examination of the watery liquid in the ascidia of Nepenthes destillatoria. Those present at the meeting, as well as the readers of the * Annals of Natural History/ will remember that, in opposition to the state- ments of most botanists who have directed their attention to the subject of the watery secretions of the leaves of plants, I found the liquid in the ascidia of Nepenthes to differ materially from pure water, inasmuch as it contained from 0*30 to nearly 1 per cent, of solid substances, partly organic partly inorganic. I stated at that time my doubts as to the watery secretion of plants being nothing but pure water, and gave some reasons for this opinion ; Prof. Balfour, with whom I discussed the subject, kindly furnished me with the means of investigating this point still further by favouring me with fresh specimens of the curious Ice-plant {Mesembryanthemum crystallinum), a plant which is re- markable on account of the gland-like vesicular eminences with which its leaves and stems are covered. The result of the examina- tion of the fluid secreted by the leaves of this plant has fully con- firmed the opinion expressed in regard to the watery secretions of plants; at all events it has shown me that the secretion of the leaves of the Ice-plant is not merely pure water, but water containing several substances in solution. Though I was unable to determine quantitatively the composition of this secretion on account of the small quantity of liquid at my command — a quantity, insufficient even for a minute qualitative analysis — yet I had no difficulty in detecting the chief constituent parts of the fluid. The secre- tion I procured by lacerating the gland-like eminences with * Read before the Botanical Society of Edinburgh, Jan. 10, 1850. 2 On the Secretion of the Leaves and Stems of the Ice-plant. which the leaves are covered, with a needle, and collecting the fluid in a glass bottle. The fluid thus obtained was colourless and nearly clear, without smell, and possessing no distinctly pronounced taste. Litmus-paper dipped in it was very slightly turned red, showing the presence of merely traces of a free acid or an acid salt. In order to free it entirely from any particles of epidermis which might accidentally have mingled with the liquid, I filtered it through white filtering-paper. The fluid passing through the filter slowly was now perfectly clear. On heating to 212° F. white flakes were separated, which proved to be iden- tical with vegetable albumen. They were collected in a filter, and the filtrate evaporated to dryness on a water-bath. During the evaporation the hquid turned yellow, particularly when evapo- rated to a small bulk, and left a brownish-coloured, very hygro- scopic residue, which redissolved in a small quantity of distilled water, leaving but a trace of a humus-like, dark-coloured organic substance undissolved. The chemical nature of the fluid from which the albumen had been separated, was ascertained as far as possible by the follow- ing tests : — Ammonia produced no change. Carbonate of ammonia gave no precipitate. Carbonate of soda on boiling gave a white precipitate. Oxalate of ammonia produced no change. Phosphate of soda and ammonia, added to the concentrated liquid, gave a crystalline white precipitate of phosphate of mag- nesia and ammonia. Chloride of platinum, added to the concentrated liquid after the removal of the magnesia, produced a crystalline yellow pre- cipitate. The presence of soda was indicated by the yellow colour given to the alcohol flame. Lime-water produced a white precipitate. Sulphate of lime likewise produced a white precipitate. Chloride of barium gave a heavy white precipitate. Nitrate of silver gave a white flaky precipitate, soluble in am- monia, but insoluble in nitric acid. Acetate of lead produced a white precipitate. Basic acetate of lead gave a voluminous white precipitate. A portion of the water evaporated to dryness and heated to redness left a white ash which effervesced with acids, indicating the presence of carbonates, originated from organic acids present in the fluid. The nature of the organic acids, which in all likelihood ac- companied the oxalic acid, I could not determine from want of material. The presence of oxalic acid however is distinctly indi- On the Secretion of the Leaves and Stems of the Ice-plant. 3 cated by the above reactions. They likewise show the presence of chloride of sodium, potash, sulphuric acid and magnesia. In comparing this secretion of the leaves of the Ice-plant with the fluid in the ascidia of Nepenthes, we find a material difierence in their respective compositions, as will be seen by the annexed table, which exhibits the composition of both fluids : — Composition of the watery secretion of the leaves of Mesembryanthe- mum crystallinum. Organic matter (albumen, oxalic acid, &c.). Chloride of sodium. Potash. Magnesia. Sulphuric acid. Composition of the fluid in the ascidia of Nepenthes. Organic matter, chiefly malic and a little citric acid. Chloride of potassium. Soda. Lime. Magnesia. 2 On the Secretion of the Leaves and Stems of the Ice-plant. which the leaves are covered, with a needle, and collecting the fluid in a glass bottle. The fluid thus obtained was colourless and nearly clear, without smell, and possessing no distinctly pronounced taste. Litmus-paper dipped in it was very slightly turned red, showing the presence of merely traces of a free acid or an acid salt. In order to free it entirely from any particles of epidermis which might accidentally have mingled with the liquid, I filtered it through white filtering-paper. The fluid passing through the filter slowly was now perfectly clear. On heating to 212° F. white flakes were separated, which proved to be iden- tical with vegetable albumen. They were collected in a filter, and the filtrate evaporated to dryness on a water-bath. During the evaporation the liquid turned yellow, particularly when evapo- rated to a small bulk, and left a brownish-coloured, very hygro- scopic residue, which redissolved in a small quantity of distilled water, leaving but a trace of a humus-like, dark-coloured organic substance undissolved. The chemical nature of the fluid from which the albumen had been separated, was ascertained as far as possible by the follow- ing tests : — Ammonia produced no change. Carbonate of ammonia gave no precipitate. Carbonate of soda on boiling gave a white precipitate. Oxalate of ammonia produced no change. Phosphate of soda and ammonia, added to the concentrated liquid, gave a crystalHne white precipitate of phosphate of mag- nesia and ammonia. Chloride of platinum, added to the concentrated liquid after the removal of the magnesia, produced a crystalline yellow pre- cipitate. The presence of soda was indicated by the yellow colour given to the alcohol flame. Lime-water produced a white precipitate. Sulphate of lime likewise produced a white precipitate. Chloride of barium gave a heavy white precipitate. Nitrate of silver gave a white flaky precipitate, soluble in am- monia, but insoluble in nitric acid. Acetate of lead produced a white precipitate. Basic acetate of lead gave a voluminous white precipitate. A portion of the water evaporated to dryness and heated to redness left a white ash which effervesced with acids, indicating the presence of carbonates, originated from organic acids present in the fluid. The nature of the organic acids, which in all likelihood ac- companied the oxalic acid, I could not determine from want of material. The presence of oxalic acid however is distinctly indi- On the Secretion of the Leaves and Stems of the Ice-plant. 3 cated by the above reactions. They likewise show the presence of chloride of sodium, potash, sulphuric acid and magnesia. In comparing this secretion of the leaves of the Ice-plant with the fluid in the ascidia of Nepenthes, we find a material difference in their respective compositions, as will be seen by the annexed table, which exhibits the composition of both fluids : — Composition of the fluid in the ascidia of Nepenthes. Organic matter, chiefly maUc and a Httle citi'ic acid. Chloride of potassium. Soda. Lime. Magnesia. Composition of the watery secretion of the leaves of Mesembryanthe- mum crystalHnum. Organic matter (albumen, oxahc acid, &c.). Chloride of sodium. Potash. Magnesia. Sulphuric acid. From the Journal of Agriculture, and Transactions of the Iliyhland and Agricultural Society of Scotland, March 1851. The Effects of Burnt Clay as a Manure, By Dr Voelcker, Professor of Chemistry in the Royal Agricultural College, Cirencester. — One of the best means of improving stiff clay land, next to thorough drainage, is the practice of soil-burning — an operation which must not be confounded with paring and burning. The latter affects merely the surface soil, whilst in the former, the soil under the vegetable mould is also burned with faggots, brush- wood, grass-sods, all kind of vegetable refuse matter and coal, where it can be obtained at a cheap rate. The advantages result- ing from burning clay land are so manifest, that in districts where such land abounds, as in the counties of Suffolk, Essex, Gloucester- shire, and in localities situated on the Oxford clay, the system of soil-burning has been long since introduced with the best effects. Properly burnt clay is, therefore, justly considered by many farmers as one of the most valuable fertilising materials, which not only improves the first crop, but likewise decidedly benefits several succeeding crops. We have the testimony of several good farmers, that the effects of burnt clay are shown in some instances, even after a lapse of eight years, by the more luxuriant growth of crops and land dressed with burnt clay, when compared with those growing in soils which had not received such a dressing. It would be easy to cite many experiments made both on a small and on an extensive scale in Britain and on the Continent, together with the opinions of high agricultural authorities, all tending to prove the advantages resulting from the application of burnt clay, were such arguments necessary to convince the sceptical on the subject. To produce such conviction is not, however, the object of the following observations. I shall, therefore, merely refer to one or two experiments conducted under peculiar advantages, and afford- ing much instruction. Those who desire further information on the subject, may find it in the valuable papers published in the Journal of the Royal Agricultural Society of England^ by Mr Pym, vol. iii. p. 323 ; Mr Randell, vol. v. p. 113 ; Mr Pusey, vol. vi. p. 477 ; Mr Mechi, vol. vii. p. 297 ; Mr Poppy, vol. vii. p. 142 ; and Mr Long, vol. vii. p. 245. Mr Pusey testifies to the good effects of burnt clay, chiefly, as he says, on account of the very bad quality of the land on which the burning succeeded. The soil was like bird-lime in wet weather, and in a dry summer like stone, and was purchased for £14 per acre. It was drained with 34 inch drains, at first at 10 feet apart, and then at 30 feet apart. After burning the clay with Essex labourers, a field of 8 acres yielded the following returns of wheat, the natural soil yielding only 16 bushels per acre : — One acre. Wheat. With no manure, ..... 37| bushels. .. 80 yards of burnt clay, . . . 45^ and sheep folded, . 474 The draining cost £3, Is., and burning the clay £2, 5s. per acre. The produce was worth £17 per acre. Mr Pusey justly observes, that burnt clay does not act merely mechanically, but also as a manure, (that is, chemically.) The reason, however, why it does so, and sometimes fails to do so, he does not attempt to explain. To elicit from the nature of the chemical changes, produced by the process of burning, and from ' a consideration of the various circumstances under which it may be performed, some solution of those questions has been the object of my investigation. Practical men agree that clay-burning is rather a nice operation, and requires much attention and judgment on the part of the operator. It is well known that, if the heat in burning clay is allowed to become too intense, the result will be that, instead of a friable mass, large hard lumps, resembling brick-bats, will be produced, which rather injure than improve the soil. It is fair to infer, therefore, that ignorance or carelessness, in this respect, accounts for the failure of some cases. All failures, however, cannot be attributed to this cause ; for many men, well acquainted with the subject, affirm that some kinds of clay are unfit for burning, because the increase of the crops is not adequate to the expense and trouble of burning and spreading this kind of manure. Now, it is clear that, unless we know the true cause of the effect produced by the application of burnt clay, we are not likely easily to settle, without incurring much expense, which kind of clay is well adapted for burning, and which not. At the same time, the discovery of the cause of the efficacy of burnt clay might lead us to supply the same substances or materials, on which the effects in burnt clay depend, in another form at a cheaper rate. An addi- tional advantage may be derived from this consideration, by which improvements are likely to be effected in the existing methods of burning clay, which shall render them easier, cheaper, and more certain. These and similar considerations, I think, will at once show the practical importance of a thoroughly fundamental investigation of this subject. The analyses of different samples of agricultural clays, taken from several geological formations, and even those of the same geological epoch, afford great differences in their chemical constitu- ents. Such clays are generally composed of alumina, silica, oxide of iron, manganese, lime, magnesia, potash, soda, traces of sul- phuric and phosphoric acid, and chlorine, in different proportions. It is perhaps just on account of the complexity of composition, and the various changes in the chemical relation of these different constituents, under so powerful an agent as heat, that the diffi- culty of settling the above questions arises. Room for much speculation is the necessary result of these circumstances ; conse- quently many theories with regard to the effects of burnt clay 8 have from time to time been advanced by agriculturists and chemists. Even though such a high authority on agricultural chemistry as that of Liebig had made us acquainted with a theory, in explanation of these effects, it must be confessed — and practical men as well as agricultural chemists acknowledge — that we have still much to learn on the subject, before we can, with any amount of probability, offer an explanation of these various effects. With a view of contributing something to the solution of the problem, I made some experiments during last winter, which have furnished me some interesting analytical results. These, I trust, will throw some light on the rationale of clay-burning, and at the same time show the importance of a more extensive practical application of the process on heavy clay lands. Before submitting to the reader my own results, I shall take a rapid survey of the history of the observations of others on the subject. It has been mentioned already that burnt clay appears to have been used as a manure long ago. Amongst those who recommended it, Robert Sommerville, and particularly General Beatson, deserve notice. The General, in his book entitled New System of Cultiva- tion^ without Manure^ Lime^ or Fallow^ of which a second edition appeared in 1821, mentions the names of Curwen, Boyd, Cart- wright, Cray, and others, as observers of the beneficial effects of burnt clay on vegetation, and strongly recommends the practice of soil-burning, as one of the best means of improving land, especially stiff heavy clay soil. The appearance of this work created some sensation at the time amongst the agricultural com- munity and the scientific public, both in this country and on the Continent. It excited, indeed, the curiosity of German agricultural chemists in a high degree, and occupied the attention of several eminent Continental philosophers, in a measure which was scarcely equalled by the attention bestowed on the subject by the scientific men of England. Sprengel, the celebrated German agricultural chemist. Professor Hermbstadt, Professor Kastner, Professor Zierl, Kersten, and, above all. Professor Lampadius, took up the subject with much warmth, and each speculated, after his own manner, on the causes of the alleged beneficial effects of burnt clay. A short review of the labours of these distinguished men, which by no means are so well known by the agricultural public of Great Britain as they deserve, I trust will not be unacceptable to the reader, if it were only for the purpose of demonstrating how fallible the judgments of even great men are, and of incul- cating the moral lesson so frequently forgotten by theoretical writers, that theories should be put forward with the utmost caution and modesty. How often do we find a favourite theory offered to the public in a manner in which only a mathematical truth, or a law of nature, confirmed by the experience and labours of many generations, can be advanced, and, after all, the same 4 theory, stated with so much confidence, and often arrogance, appeaVs very erroneous and even absurd, as the circle of our experience expands. Fortunately for such a theorist, this seldom takes place in his lifetime, but sometimes the decline of his life is embittered by seeing the dreams of his enthusiasm vanishing and exploded, and exposed to the ridicule and scorn of his contempo- raries. We long to see the time when caution, modesty, a generous regard for the opinions of others, and, above all, a love of truth for its own sake, shall characterise the mind of natural philosophers, and feel convinced that men whose spirit is so con- stituted, will not only enjoy themselves a greater amount of happi- ness and satisfaction, but that the cause in which they are engaged will be decidedly a gainer, and advance more rapidly, and prosper better than it now does. It must be regarded as a matter of deep regret, that the want of caution and modesty on the part of many scientific men has contributed more than perhaps anything else to bring science into discredit with the agricultural public. Many a practical man, not otherwise entertaining prejudices against science, has been led thereby to undervalue the labours of his best friends, and to regard science — a term of which he often entertains very vague ideas — as antagonistic to practice. In my conversations with farmers, it has often struck me how generally the words practice with science^ which several agricultural societies have accepted as their motto, are misdunerstood. Mere theory and science are synonymous terms, I fear, with most farmers ; and many, I am convinced, regard science as the very antagonist principle to prac- tice ; and if they adopt the motto Science with Practice, I think it is only because, in their opinion, a little opposition — that is, a little science or theory — keeps a good practice alive. Now nothing can be more incorrect. True science and practice are never opposed to each other. The source from which both are upheld is observation. Well-regulated observation constitutes experience: experience is the mother of sound practice, but it is also the parent of sound science ; for science itself is nothing else than the systematic arrangement or generalisation of a number of isolated facts. Where, then, is the antagonistic principle between science and practice I The labours of Lampadius demand our special notice. With much interest and zeal he took up the investigation into the causes of the beneficial efi'ects resulting from the application of burnt clay, brick-dust, and burnt soil in general ; and during the years of 1829-36, he continued his experiments, which are full of instruc- tion, with a perseverance which cannot be too highly commended. The results of his experiments are recorded in a series of papers which appeared in Erdmann"'s Journal fur Technische und (Econo- miscJie Uheinie^ during the years of 1826-36 ; and as they are valu- able contributions to our agricultural literature, we will point out the more important of them, and briefly state the theoretical con- clusions to which they lead the praiseworthy investigator. Hap- pily he did not confine his experiments to the laboratory, nor to the practical tests of a few flower-pots or a slip of garden land, but conducted them on a large scale in a truly philosophical man- ner in the field. Although, we believe, he mistook the causes of the advantages of burnt clay, his labours have advanced scientific agriculture in no small degree, and contributed much to the more general application of this valuable manure. They also afford some data to succeeding investigators, who are happier in their conclusions. The result at which Lampadius arrived, by numerous well premeditated and carefully executed experiments, may be briefly thus stated : Properly burnt clay acts on a variety of crops — as on wheat, barley, oats, green crops, and particularly on potatoes — as a most valuable manure. One of his experiments will serve sufficiently for illustration ; and without entering into further details, it may be observed that few experiments have recently been recorded which possess more intrinsic value, and that few men were better fitted to submit the alleged effects of burnt clay to a severer test than Lampadius. Not only his extensive theoretical chemical knowledge and practical acquaintance with analysis, but also his acquaintance with practical farm operations, his physiolo- gical and meteorological knowledge, his acute talent of observation, adaptation, circumspection, and general skill in devising plans and carrying them out in a truly philosophical spirit, peculiarly fitted him for the task he had undertaken. We thus find him testing the results of the laboratory by experiments on a small scale, and these by others in the field. The physical characters of the soil on which the experiments were made were carefully described, its geological formation on which it rests specified, and its chemical composition ascertained by analysis ; the preceding crops, fur- ther, grown on it for several years back were noted down. Be- sides this, the quantity of rain fallen during the season, the tem- perature, height of the barometer, and general state of the weather, the condition of the crop, from the beginning of the germination of the seed to the period of its maturity, were carefully recorded. The produce, in every case, was ascertained in exact numbers— obtained by means of balance and measure ; and lastly, the composition of the produce was determined by analysis, in order to decide the in- feriority or superiority of the same crop grown with different manuring substances. In addition to all this, minutes were kept of all the incidents which might have affected the ultimate rcvsults; and thus data are supplied which render his experiments valuable for all ages, The experiment which we shall choose for an example \v^s made on exhausted land, from which, in 1829, a crop of winter rye, and in 1830 and 18.31 oats, were grown. The nature and composition of the land wa.s pr^\5ipusly aaceTtajned, as well a,s th^,t.qf^ th^ seed- 6 potatoes, for it was on potatoes he experimented. The potatoes were planted on the 3d of May 1832. 1. On the first plot of the experimental field, 28 lb. of white potatoes were planted in two rows, and the ground manured with farm-yard manure. 2. On the second, 28 lb. of the same potatoes were planted, and the ground man- ured with 136 lb. of burnt clay, and the same quantity of manure as that applied on the first plot. 3. The third received 130 lb. of burnt clay only, and the same quantity of pota- toes, (28 lb.) 4. On the fourth plot, 28 lb. of the same potatoes were grown without any man- ure whatever. The produce was collected on the 27th of September, and gave — 1. 278 lb. of full-grown potatoes, with but few small ones. Some of the larger weighed from 5 4 to 64 ounces ; the weight of most was 2 to 3 ounces. 2. 280 lb. of equally good potatoes. Some of the larger weighed 6 to 8 ounces. There were few under 1 ounce. 3. 276 lb. of perfectly matured, very good potatoes. Most were middle-sized, of 3 to 4 ounces weight, with but few small ones. 4. 127 lb. only of potatoes, of a scarcely mediocre quality, mixed with many small ones which had not come to perfection. The plants produced only a few seeds, whereas the potato plants in No. 3. furnished even a greater abundance of seed- apples than those planted in No. 1 . In comparison with the seed-potatoes, the produce of the four plots was therefore — 1. In the field manured with farm-yard manure, ten-fold. 2. In the field manured with farm-yard manure and burnt clay, nearly eleven-fold. 3. In the field manured with burnt clay only, nearly ten-fold. 4. In the field without manure, only a little more than four-fold. In these experiments, the highly profitable effects of burnt clay on the potato crop, grown on perfectly exhausted land, are exhibited in a most convincing manner. Passing over the details of the subsequent chemical analyses, to which not only the tuber, but likewise the roots, stem, leaves, and seeds of the potato plants were subjected by Lampadius, the fol- lowing are the ultimate results at which he arrived: — o. Burnt clay benefits the growth of potatoes on the poor loam of the neighbour- hood of Freiberg nearly as much as mixed animal and vegetable manure, (common farm-yard manure.) b. The tubers of the potato plants furnish the same quantity of starch, fibre, and water, whether they be grown with farm-yard manure or with burnt clay. c. The seed-apples, roots, stems, tubers, and leaves of the potato plants, contain the same inorganic constituents, and in the same relative proportions, when grown with burnt clay or with farm-yard manure. d. The amount of inorganic matters in the different parts of the potato plants dif- fer very considerably. In order to give an idea of the spirited manner in which Lam- padius carried out similar experiments, I would draw the attention of the reader to the fact that, in the same year, this indefatigable philosopher tested the effects of burnt clay on no less than twenty different crops, in a manner which proved forcibly the economic value of this kind of manure. He further caused many farmers to try experiments with burnt clay on a large scale, and had the satisfaction to see his own experiments confirmed by the experi- ence of many practical farmers. So successful, indeed, were nearly all his experiments, and so much the interest of the agriculturaU community of Germany excited by Lampadius's labours, that, by command of the Government, public establishments were erected ill various parts of the country for the purpose of supplying far- mers, at a cheap rate, with properly burnt and finely powdered clay. The crops which were benefited most by the application of burnt clay, next to potatoes, were ascertained by Lampadius to be peas, kohl- rabi, carrots, beetroot, clover, oats, rye, and wheat. Less favour- able he found its use as a top-dressing for pasture land. It is worthy of remark that the good effects of burnt clay were observed on beans, kohl-rabi, and carrots, after the third year, without re- ceiving any additional manure. Having thus shown on what grounds Lampadius recommended the more general use of burnt clay, we shall now endeavour to collect from his extensive papers the theories he advanced to account for these extraordinary and interesting effects. At first he appears to be inclined to ascribe to humate of alumina, which according to him is formed in the soil, a highly beneficial action on vegetation, and hints that burnt clay would fail in its effects when the soil was exhausted of humus ; but having soon after found that burnt clay in soil destitute of humus produced, nevertheless, unmistakeable effects, he soon gave up this theory, and next explained the effect, by saying that clay in burning undergoes some peculiar unexplained changes, by which changes the manuring substances in clay are rendered available to plants. It will be observed that this explanation amounts to little more than stating the fact in other terms. Indeed, the modified and varied opinions Lampadius entertained afterwards on this subject clearly show how little satisfied he was with this theory. As the probable causes of the efi'ects of burnt clay, he mentions in 1833 :— a. The changes in the state of aggregation clay undergoes in burning. h. The decomposition of the hydrates occurring in clay. c. The changes which the earthy substances of the clay undergo in burning, which changes render them more soluble in the humic acids of the soil. d. The higher state of oxidation of the oxides of iron and manganese produced in burning clay. e. The production of a larger quantity of soluble sulphates, phosphates, and hydro- chlorates, which, previous to burning, occur in a more fixed state in clay. /. The absorption of light and heat by burnt clay. g. According to Dr Sprengel, the formation of ammonia in burnt clay. Several of these opinions were abandoned by Lampadius, who, in 1834, ascribes the effects of burnt clay to the following causes : — (1.) To the inorganic constituent parts of unburnt and burnt clay, which are essential to the growth of cultivated plants. (2.) These constituents are rendered more soluble, in various ways, in moderately burnt clay. Unburut clay gave 0.20 soluble matters; moderately burnt clay, 0.30 soluble salts. Humic acid dissolves likewise silicate of alumina, and f the other constituents of clay, more readily when clay has been previously burnt. (3.) The protoxide of iron in the clay takes up more oxygen in burning, and be- comes converted into peroxide, which, according to Sprengel, acts beneficially on vegetation, whilst protoxide of iron is rather injurious to many vege- tables. (4.) In burnt clay, ammouia is formed when exposed to the atmosphere in a moist state. In his last concluding paper on this subject, Lampadius advanced finally the following theories : — a. Plants are supplied by burnt clay with humates of alumina and silica. b. In burnt clay, exposed to moist atmospheric air, ammouia, which is beneficial to vegetation, is formed according to his own, Sprengel's, and Kersten's obser- vations. c. According to Zierl, accessory constituents of clay, as phosphoric acid and pot- ash, contribute to the fertilising effects of burnt clay. These, then, are the theoretical opinions advanced by Lampa- dius, and we shall see presently how far they are consistent with the present state of science ; but, in order to avoid repetition, we shall first briefly state the opinions of others who have written on the subject, and shall tlien submit the various theories, which all more or less agree with Lampadius, to a short review. Karl Kersten, who analysed a sample of clay, both in its natu- ral state and burnt, could detect no material difference in tlie composition of the burnt and the natural clay. The only difi'er- ence which he points out consists in a slightly greater amount of soluble matter — the amount of soluble substances in the natural clay being 0.20 ; in the burnt, 0.30. On so small a difference no theoretical speculation can be built, inasmuch as the unavoidable errors in good analyses fall between these limits. Kersten likewise observed the formation of ammonia in burnt clay which had been exposed to the atmosphere for some time, and inclines to ascribe to the latter the chief fertilising effects of burnt clay. No men- tion is made of the presence of ammonia in the natural clay. Professor Kastner thinks clay, when burnt, absorbs light, which being given off again in the soil, exercises a beneficial effect on vegetation ; but as his theory is founded on no experimental proof, we can dismiss it without any further inquiry into the pro- bability of the explanation he has given. Dr SprengePs extensive researches on a multitude of chemico- agricultural subjects — amongst others, on the causes of the benefi- cial effects of burnt clay — are valuable contributions to scientific agriculture. The theory which he first advanced enjoyed the approbation of many of his contemporaries, and is partly still entertained by no less an authority than Liebig, and other eminent chemists of the present day. This theory is generally called the ammonia-theory. According to it, the chief fertilising agent in burnt clay is ammonia, which Sprengel supposes to be formed in burnt clay under the influence of protoxide of iron, from the elements of water and atmospheric air, and which, according to Liebig and others, exists ready formed in the atmosphere, whence it is simply absorbed by the clay. The clay being more 9 porous after burning, they suppose absorbs more ammonia, and acts, consequently, more beneficial on vegetation than unburnt. At first Sprengel attributed the effects of burnt clay to the cir- cumstance that, in burning, the protoxide of iron, existing in many natural clays, is changed into peroxide, which he considers to be more beneficial to vegetation than the protoxide. SprengeFs second explanation entirely contradicts this statement, inasmuch as, according to it, during the burning process the peroxide of iron in clays is changed into protoxide — to which now he ascribes the greatest importance, as being the chief agent in the formation of ammonia in burnt clay ; for, in slightly burnt clay, protoxide of iron is always present ; and, as it has been ascertained by Haus- mann and others, ammonia is formed when protoxide of iron, moistened with water, is kept in contact with nitrogen. Sprengel explains the beneficial action of burnt clay by the formation of ammonia, which is generated in it in the following manner : — The protoxide of iron, of which burnt clay usually contains more than unburnt clay, when exposed to the atmosphere in a moist state, is converted into peroxide by the oxygen of the water ; the hydrogen of the decomposed water, in the moment of its liberation, unites with the free nitrogen of the atmosphere to ammonia, which is retained by the humic acids present in all cultivated plants. According to SprengeFs views, the more protoxide of iron clay after burning contains, the more certain it will appear in its effects, because more ammonia will be formed : burnt clay will cease to exhibit the same fertilising effects when all the protoxide of iron has become changed by oxidation into peroxide, because then no more ammonia can be formed. This is the case in overburnt clay, which contains peroxide of iron only, and no protoxide : overburnt clay thus exercises no beneficial effects on vegetation, because no ammonia is formed in it on exposure to the air. So much for SprengePs theory. The ammonia, then, which in burnt clay is formed during the oxidation of the protoxide of iron, Sprengel considers as the chief cause of action of burnt clay; at the same time he ascribes to the necessary constituents of clay, as potash, soda, lime, magnesia, &c., some influence in promoting the growth of plants ; and agrees likewise with Lampadius''s opinion, that humate of alumina, which he considers an important sub- stance in the vegetable processes, is more readily produced in burnt clay than in unburnt. The recent analyses of the ashes of most cultivated plants have shown the entire absence of alumina in plants ; Lampadius and SprerigeFs theory concerning the action of humate of alumina, therefore, falls to the ground. That ammonia exists in burnt clay Sprengel has demonstrated, by heating clay, free from organic matters; exposing the same, in a moist state, for three days to the atmosphere; and after that time heating the clay in a retort, to which a receiver was attached, containing water acidulated with 10 hydrochloric acid. On evaporation of the liquid in the receiver, distinct crystals of sal-ammoniac were left behind in the basin in which the liquid was evaporated. The repetition of this experi- ment gave me the same result. However, Sprengel erred in think- ing that ammonia is formed only in those clays which contain protoxide of iron, for I have found that in clay which contains not a trace of protoxide of iron, ammonia is found after exposure to the atmosphere for some time. It cannot be denied that protoxide of iron, in contact with moisture and atmospheric air, gives rise to the formation of ammonia ; but the proof that in burnt clay a greater quantity of ammonia is found, because it contains, as Sprengel supposes, more protoxide of iron, he has not furnished ; and his theory loses much in probability, by the consideration that ammonia is found in clay containing only peroxide of iron ; and further, that certain blue clays, in their natural state, contain protoxide of iron in preference, with but little peroxide. If it was true that the ammonia is the chief cause of the effects of burnt clay, and that it is formed in clay under the influence of pro- toxide of iron, from water and atmospheric air, these blue clays ought to possess the same effects as burnt clay, or exhibit even greater fertilising effects than most burnt cla^'s. The contrary, however, is the case. Sprengel appears to have felt the difficulty which presents itself in explaining why certain blue clays, which contain a large quantity of protoxide of iron, do not act so beneficially as burnt clays, containing much less protoxide ; and he endeavours to meet it, by a reference to the changes which protoxide of iron undergoes during heating. He says, in unburnt clay, protoxide of iron occurs in a state of hydrate ; on burning, it is changed into anhydrous protoxide, in which state it possesses the greatest gal- vanic energy, in consequence of which a larger decomposition of water, and also more considerable formation of ammonia, results. This explanation, probable as it may appear at first sight, never- tlieless wants the only proof on which any explanation can be founded — namely, direct experiment — and amounts, therefore, to nothing more than explaining one difficulty by assuming another. For my own part, I cannot see why anhydrous protoxide of iron should be in a state of greater galvanic energy, and consequently produce more ammonia than the hydrated protoxide; and as Sprengel has not shown, by direct experiment, that this is really the case, the difficulty which presents itself to his ammonia-theory in certain blue clays cannot be said to be removed. We shall see hereafter that ammonia, which is found in burnt clay, indeed con- tributes to the general effect of the same; but we shall likewise see that it is not the chief cause. "The part ammonia plays in pro- ducing these effects will be discussed afterwards. It is now time to allude to the opinions which Professor Zierl entertained respecting the causes of the influence of burnt clay. Unlike Lampadius, Kersten, and Sprengel, he considers the acci- 11 dental constituents of agricultural clays as the chief causes of the fertilising effects of burnt cla^^ Without giving any experimental support to his theory, he reasons, with much probability, oy analogy, that some of these accessory constituents of clay, particularly potash, soda, lime, and magnesia, are rendered more soluble in the process of burning. To this circumstance he ascribes the chief causes of the effects of burnt clay. It is curious that his theory, set forth with much perspicuity and ingenuity, was by no means generally well received at the time of its publication. Nevertheless, Zierl's theory seems to me the most rational of all the theories which have been advanced. Without a previous knowledge of Zieri's paper, or the causes of the effects of burnt clay, I have formed a theory which, in many respects, agrees with his ; and when I shall bring forward the facts by which I hope to support my theory, 1 shall point out the importance of Professor Zierl's speculations, which, unfortunately for him, were not borne out by any testimony or experiment. It now remains for me only to say a few words about the opinion which Professor Hermbst'adt advanced in a paper, which appeared in ErdmanrCs Journal for ] 833, vol. i. p. 45, concerning the effects of burnt clay. His views on the use of inorganic constituents of the soil to plants are so entirely at variance with the generally accepted opinions of chemists and physiologists, that the endeavour to refute them might appear as a waste of words and of time. The same remark applies to his views concerning the effects of burnt clay ; and we shall, therefore, onl}^ mention, that Professor Hermbstadt refers the active principle of burnt clay entirely to the organic matters which have not been destroyed by the fire. For obvious reasons, he is no advocate of the use of burnt clay ; and, although Lampadius's, and many other practical experiments, were published in 1833, he prophesies a total failure to General Beatson''s recommendations. Inconsistent as his own views were with the state of science in 1833, he charges General Beatson with ignorance of the first principles of the theory of manures, and this in terms which cannot be too highly deprecated. Ought not his example to make us more charitably inclined towards the opinions of others — more guarded and milder in our expressions, and less confident and dogmatic in propounding our own views I From these remarks the reader will perceive that none of the above-mentioned theories explains satisfactorily the cause of the decidedly beneficial effects of burnt clay ; that SprengeFs, Lampadius^s, and Kersten's theory, concerning the use of ammonia, and the modified ammonia-theory of Liebig, are open to serious objections. Furthermore, none explains in the least why certain clays, when properly burnt, act more beneficially than otliers, and what the reasons are which explain the failures attending the application of over-burnt clay. Alost living agriculturists and agricultural chemists have adopted Liebig's views respecting the nature of the action of burnt clay, 12 or consider the action to be entirely dependant on tlie altered physical state which clay aftyor burning presents. Of recent writers on the subject, Professor Johnston, however, entertains much more rational and wider views than any of his predecessors. Giving all due importance to the mechanical effects of burning upon clay, Professor Johnston, in an excellent paper in his Experimental Agriculture^ p. 254, shows that the mechanical effects of burning upon a clay are insufficient to explain the bene- ficial action of burnt clay, and demonstrates experimentally that the chemical changes produced in burning are of even a greater importance than the mechanical. " These chemical changes," the learned Professor says, " are of such a kind as to render the constituents of the clay more soluble — that is, soluble to a greater extent than before the burning — both in water and in acids." He further found by analysis, that by over-burning, new changes among the constituents of the clay take place, by which they are again rendered less soluble than when slightly burnt. The soluble matter consisted of potash, soda, lime, magnesia, chlorine, sulphuric acid, silica. The relative proportion of these substances, however, is not stated in the above-mentioned work, from which I infer that the nature of the soluble matters has been examined by Professor Johnston only qualitatively. By my own experiments, 1 am enabled to confirm Kersten's and Johnston's observations of the greater solubility of burnt clay, and the observation of Johnston, that clay again, becomes less soluble on over-burning. In addition to this, the quantitative analyses of a clay, burnt in three different modes, has given me results which will throw considerable light on the causes of the action of burnt clay. The mere fact that clay becomes more soluble in water and acids, appears to me insufficient to explain the beneficial effects of burnt clay ; for it is quite possible that alumina, oxide of iron, or any other unimportant element of clay, of which most soils contain already sufficient quantities, is rendered soluble. It is evident that the greater solubility of any of such substances would increase the quantity of soluble matter, without adding anything to the aggregate fertilising effects of burnt clay. Pure pipe-clay, slightly burnt, is indeed more soluble in acids than the unburntclay. Sulphuric acid decomposes moderately burnt clay, and dissolves, on boiling, all alumina, leaving the silica, with which the latter was combined, behind, whereas concentrated sulphuric acid has but little action on clay in the unburnt state. The greater solubility of burnt clay in itself, then, is insufficient to account for the effects of burnt clay. But this objection stands no longer in our way, since we are in a position to show that, in burning, one of the most important fertilising substances which is found in clay, if not the most important of all, is rendered more soluble.* * Want of space obliges us to postpone the remainder of this interesting paper to Fr&m the Journal of Agriculture, and Transactions of the Highland and AgricuUural Society qf Scotland, October 1851. Effects of Burnt Clay as a Manure. By Dr Voelcker, Professor of Chemistry in the Royal Agricultural College, Cirencester. — [Concluded from p. 79.) — In burning clay properly, I have found that a much larger amount oi potash is rendered soluble, in a way which I shall explain, after having given the details of my analyses. But every physiologist knows that potash is one of the most valuable and essential food of plants. I am inclined, therefore, to consider the fact, that potash being rendered more soluble on burning clay, is the chief cause of the beneficial effects of burnt clay. I am indebted to Sir Thomas Tancred for the material with which my experiments were made. Having procured for me some clay of the new red sandstone formation from the farm of Huntstile, near Bridgewater, tenanted by Mr Thomas Danger, I proposed to myself the following ques- tions :^— 1. Is this clay more soluble after burning than in its natural state ? 2. What are the relative proportions of insoluble and soluble matters in this clay, when burnt in different manners ? 3. What is the relative composition of the soluble portion in each case ? 4. Is it essential or desirable that clays fit for burning should contain lime ? 5. What are the characteristics of clays, of which it can be said that they are totally unfit for burning ? 6; Can it be determined by chemical analysis whether burning will be efficacious in rendering clay a fertiliser ? 7. What are the reasons of the failure attending over-burning ? 8. Does moderately burnt clay absorb more ammonia from the atmosphere than unburnt clay ? 9. Does over-burnt clay absorb any or no ammonia from the atmosphere ? 10. Is ammonia found in burnt clay, containing protoxide of iron, when exposed in a moist state to the atmosphere in much larger quantities than in the same clay exposed in a dry state to the atmosphere ? 11. What is the reason that burnt clays improve, especially root and other green crops, as Mr Woodward states? The nature of the chemical changes, which may be supposed to affect the action of burnt clay on the land to which it is applied, was examined by four distinct analyses. No. I. Clay-soil in its natural state. No. II. A quantity of the same clay-soil was exposed to a dull 14 red heat in a closed platinum crucible, and kept at that temperature for half an hour. The clay, after burning, had a dark-grey colour. No. 111. Another portion of the same clay-soil was exposed to a red heat for half an hour in an open crucible. The contents of the crucible were frequently stirred with a platinum wire, in order to effect the complete combustion of all organic matters, and to secure the perfect oxidation of any protoxide of iron which was present in the clay. After burning, the colour of this portion of the clay was red ; rather brighter than the natural colour of the soil. No. IV. A fourth portion of the same clay-soil was exposed for about three hours to a full red heat in an open crucible. Though water, containing carbonic acid, acts more slowly, yet it produces the same effects on the constituents of clay as dilute mineral acids. I preferred to apply dilute muriatic acid instead of water charged with carbonic acid, in order to test the solubility of the above four samples of clay. Accordingly, separate quanti- ties of Nos. I., II., III., and IV., were taken for analysis, and each boiled for half an hour in four ounces of water, containing one- tenth of its bulk of hydrochloric acid ; the insoluble part of the clay was collected on a filter, and washed with distilled water until nothing more was dissolved. In the soluble part of Nos. I., II., III., and IV., the following substances were determined quantitatively : — Soluble silica, oxide of iron, and alumina ; carbonate of lime, potash, soda, and phos- phoric acid. In No. IV. phosphoric acid was not determined. The following table exhibits the results of these several ana- lyses : — No. I. No. 11. No. III. 1 No. IV. Water, driven off at 212=^ F., 5.53d \ Organic matter and water of) combination, . \ 3.621 1 9.160 9.200 9.300 Insoluble matter, (in dilute ) hydrochloric acid,) . \ 84.100 80.260 81.845 85.309 Soluble matter, consisting of — Soluble silica, . 1.450 1.380 1.580 1.150 Oxides of iron and alumina, 3.070 8.245 6.092 2.970 Carbonate of lime. .740 .420 .550 .188 Potash, .269 .941 .512 .544 1 Soda, .... .220 .336 .314 .104 Phosphoric acid. .380 .165 .128 \ Not de- \ termined Chlorine and sulphuric acid, traces traces traces traces i Magnesia, (not determined,) ... ... 99.389 100.907 100.221 99.566 The suggestions to which these analytical results give rise Avill be more intelligible after we shall have briefly considered the 15 origin and composition of agricultural clays in general, and pointed out on what substances chieilj the fertilising powers of clay depend. Clays generally result from the disintegration and degradation of granitic and felspatic rocks. Felspar, a mineral composed of silicate of potash or soda, and silicate of alumina, exposed for a long time to the united action of the atmosphere and water, suffers a gradual decomposition, and falls altogether to powder. Silicate of potash, a soluble salt, is washed out by the rain falling on the decomposed rock, and converted, in its turn, by the carbonic acid of the atmosphere into carbonate of potash and silica. Part of the silica remains behind with the insoluble silicate of alumina, the chief constituent of clays. Agricultural clays, however, are never pure silicate of alumina, but mixtures of pure clay (silicate of alu- mina) with more or less of sand, undecomposed fragments of felspar and other minerals, lime, magnesia, free alumina, oxide of iron, soluble silicate of potash and soda, and traces of phosphoric acid, chlorine, and sulphuric acid. The state of combination in which these different constituents occur, varies in different clays. The complex nature of agricultural clays will become apparent by the subjoined analyses of three samples of clays from Dumbelton, in Gloucestershire, made in my laboratory. No. 1. No. 2. No. 3. Water of combination and organic matter, Oxides of iron, .... Alumina, soluble in acids, . Alumina, in a state of silicate, Lime, carbonate of, ... Lime, in a state of insoluble silicate. Magnesia, soluble in acids. Magnesia, in a state of insoluble silicate, . Potash and soda, soluble in acids, . Potash and soda, in a state of insoluble silicate, Silica, (soluble in acids,) Silica, (insoluble in acids,) 7.69 8.24 8.04 10.04 1.12 0.44 0.62 0.34 0.73 0.94 0.09 61.71 6.62 7.33 10.62 7.06 0.70 0.54 0.12 0.39 1.04 2.70 0.06 62.82 6.68 8.63 9.25 9.66 0.19 0.24 0.56 0.34 1.13 1.82 0.08 61.42 100.00 100.00 100.00 As alumina or silicate of alumina is not found in the ashes of cultivated plants, the chief component part of clay cannot be said to contribute in itself to the direct nutrition of plants, and we have, therefore, to look amongst the accessary ingredients of clay for the fertilising agents or substances which are used as direct articles of food by plants. Lime, magnesia, sulphuric and phos- phoric acid, and chlorine — substances which, in larger or smaller quantities, occur in clays — are, indeed, essential to the growth of plants ; but the value of an agricultural clay chiefly depends on the proportion of potash and soda which it contains. Potash is an essential element in all ashes of plants, and acts as a most powerful 16 manure. The high price of salts of potash unfortunately prevents their more extensive application in agriculture, and plants are, therefore, dependent in a great measure on the natural sources from which they derive their potash. The chief source of potash in ordinary soils is the clay, which forms part of almost all soils, and which itself usually contains some undecomposed silicate of potash or a duple silicate of potash or soda and an earthy base, from which, in gradual decomposition, potash is set free and made available to plants. Clay, we have seen, is in many cases derived from felspar : the more undecomposed felspar-fragments a clay contains, the more it is likely to prove useful to plants. Hence we are enabled to explain the advantages of fallowing. By that process a fresh portion of the soil, not hitherto exposed to the action of the atmosphere, is brought up, and the undecomposed fragments of felspar are forced by the combined action of air and water, to yield their potash and soda, which are the indispensable requisites of a healthy vegetation. Without doubt, then, potash is the most valuable substance in clays, and, if I am not mistaken, the substance on which their manuring qualities mainly depends. In an age of railway and steamboat enterprise and telegraphic despatch, agriculture is forced to progress, and, in consequence of this, fallowing must necessarily yield to some more extensive and expeditious means of gaining the same advantages. Now, I am prepared to show, that, in burning clay, precisely the same changes are effected in a few days which in bare-fallowing are produced in so many months : in other words, the natural fertility of the soil, which in fallowing is restored after a long interval of rest, can be restored in many instances in a few days, by burning land. Let us,, however, examine the proposed questions separately. 1. Is the clay from Huntstile, near Bridgewater, more soluble in dilute hydrochloric acid, after than before burning ? A reference to the above tabulated analytical results will show that, after burning, this clay has become much more soluble than the clay in its natural state. 2. What are the relative proportions of soluble and insoluble matters in this clay when burnt in different manners ? The above-mentioned results not only teach, generally, that clay becomes more soluble in burning, but that the temperature to which it is exposed mainly regulates the solubility of the clay. A proper temperature for burning clay is, indeed, a condition in the process, on which the success of the operation chiefly depends. We see, from the preceding tabulated results, that clay, in 100 parts in its natural state, furnishes only 6.74 grs. of soluble inorganic matter, leaving 84.100 insoluble mineral matters behind ; whilst the same clay, burnt at a temperature, and under circum^ 17 stances under which the organic matter was not altogether de- stroyed, left 80.260 grs. of insoluble inorganic substances, and furnished 10.580 grs. of soluble inorganic matters. An increase of the temperature, sufficiently high to burn off the small amount of organic matter which enters into the composition of this clay, had the effect of producing the solubility of its constituents to about li per cent ; and a more protracted exposure to a still higher temperature had the effect of a further reduction of its solubility, to such an extent that this over-burnt clay became less soluble than the same clay in its natural state. Proportion of Soluble inorganic Insoluble mineral matter. matter. Clay, No. 1, (unburnt,) .... 6.740 84.100 Clay, No. 2, (slightly burnt,) . . 10.580 80.260 Clay, No. 3, (burnt stronger than 2,) . 8.955 81.845 Clay, No. 4, (over-burnt,) . . . 5,391 85.309 It is difficult to determine at what exact temperature clay should be burnt for agricultural purposes, and I am inclined to believe that this point cannot be settled by small experiments in the laboratory. Besides, if it could be done, the mere indication of the degree of heat would not be a sufficient guide to the practi- cal man, and therefore possesses little more than a theoretical value. Valuable results, however, might be obtained by recording the exact circumstances under which different clays have been burnt, by observing the practical effects of clay burnt in different ways, and reserving a portion of each sample of clay for chemical analysis. The analysis of a series of different clays, aud clays burnt in different manners, I have no doubt, besides .throwing additional light on the rationale of the process of soil burning, is likely to be attended with important practical results. 3. What is the relative composition of the soluble matter in clay burnt in different manners ? Keferring to the above analytical results, we find much differ- ence in the composition of the soluble portion of each of the four samples of clay ; but I would invite particular attention to the important fact, which is distinctly proved by these analyses, that the proportion of alkalies, more particularly that of potash, is much larger in the burnt than in the unburnt clay. Finding the quantity of so valuable a fertilising substance as potash very much increased in the soluble portion of burnt clay, and considering that this is precisely the effect produced in fallowing, as demon- strated above, I have no hesitation to assign the chief cause of the beneficial effects of burnt clay to a larger quantity of potash which is liberated by burning and rendered available for immediate use by plants. The temperature to which the clay has been exposed, here regulates the proportion of potash rendered soluble in dilute 18 muriatic acid in a remarkable manner. In the natural clay only 0.269 of a per cent of potash were soluble ; whereas in clay burnt at a moderate heat, and under circumstances resembling those under which clay is burnt in the field, the quantity of soluble potash amounted to more than three times the former quantity, the exact proportion of potash being 0.941 of a per cent. In clay No. 3, the higher temperature to which it was exposed caused a diminution of the last-mentioned proportion of potash, the actual number obtained, on analysis of No. 3, being 0.512 of potash, and in No. 4 nearly the same quantity of potash — namely, .544 grs. were obtained. The actual quantities of soda rendered more soluble in burn- ing are trifling, but still sufficiently large to confirm the fact that soda is rendered more soluble in burning. The higher tempera- ture applied in burning No. 3 and No. 4 likewise was attended with a slight diminution of soluble soda, when compared with No. 2. No. 1. No. 2. No. 3. No. 4. Soda, . . 0.220 0.336 0.314 0.104 Another important diff^erence in the composition of these four samples of clays — which, however, is more interesting in a theoretical than in a practical point of view — is presented in the relative quantities of lime which were found in the soluble portion of each. In clay in its natural state, the quantity of carbonate of lime amounted to 0.740 per cent ; in moderately burnt clay (No. 2) to 0.420 ; in clay burnt at a higher temperature (No. 3) to 0.550 ; and in over-burnt clay (No. 4) to 0.188. The three latter quanti- ties are marked down in the analyses as carbonate of lime, for the sake of comparison with No. 1, in which the lime really existed as carbonate of lime ; but as not the slightest effervescence took place on dissolving the burnt clay in dilute muriatic acid, it is clear that the lime did not exist in it in a state of carbonate. The lime must have existed in No. 2, No. 3, and No. 4, as caustic lime, or in a state of silicate ; it would have been, therefore, more correct to indicate the quantity of pure lime in the above table. The excess in analyses No. l,No. 2, and No. 3, is partly due to this inaccuracy of stating the results, partly to the fact that silicate of protoxide of iron, in burning, becomes decomposed. The pro- toxide of iron is rendered soluble in dilute muriatic acid, but in the analyses it is determined and calculated as peroxide of iron ; hence we find the largest excess in No. 2, in which most iron has become soluble in dilute muriatic acid. The following considerations induce me to think that the lime in Nos. 1, 2, 3, and 4 existed in a state of silicate. Chemists are well acquainted with the methods of determining the quantity of potash and soda in insoluble silicates, to which class of siHcates felspar belongs. 19 The usual method consists in fusing the finely powdered sub- stance with an excess of carbonate of baryta. In this process potash and soda are rendered soluble in the following manner ; — The baryta combines with the silica, originally present in combina- tion with potash and soda : silicate of baryta is formed, and the alkalies, potash and soda, uniting with the carbonic acid of the carbonate of baryta, are rendered soluble. Lime, which in its chemical relation is closely allied to baryta, acts precisely in the same manner on insoluble silicates of potash and soda. Now, if clay originally contains carbonate of lime, it will act at an elevated temperature on the insoluble silicate of potash, which is present in many clays in the shape of fragments of felspar ; and by duple decomposition it will give rise to the production of silicate of lime and carbonate of potash. Silica enters into combination with lime in different proportions : some of these combinations are soluble In dilute acids ; most of them are insoluble. Instead of carbonate of lime and insoluble silicate of potash, we thus find in burnt clay a larger proportion of soluble potash and silicate of lime, which is partly insoluble in acid. The diminution of the quantity of lime, and the increase of potash in the soluble portion of burnt clay, thus find a ready explanation. Much, however, as indicated by the practical observations, and the above analytical results, depends on a proper temperature. If the heat is allowed to become too Intense, new changes in the con- stituents of clay are produced, which have the effect of rendering the potash again less soluble. The fact that felspar is more readily decomposed after having been moderately calcined is not a new one, Professor Fuchs of Munich having shown clearly that this is the case, not only with felspar, but also with other minerals, into the composition of which silicate of potash enters. Fully in accordance with this fact is the practical observation of Professor Lampadius, who found, by a series of field experiments, that moderately calcined gneiss, granite, certain kinds of porphyry and trap rocks, all of which contain silicate of potash. In a similar manner as burnt clay, promote the luxuriant growth of many plants In a remarkable manner. It would be doing injustice to Professor Zierl of Munich to leave unnoticed that, in speaking of the causes of the effects of burnt clay, he suggested whether the accessary constituents of clay, particularly the alkalies, might not be rendered more soluble in the process of burning. Had Professor Zierl submitted unburnt and burnt clay to chemical analysis, he would, no doubt, have found that this was really the case; but as he brought forward no experimental proof in support of his theory. It had the fate of being disregarded by many at the time of its publication, and of being soon after forgotten by most. As far as I am aware, the above analytical results. In support of ray theory respecting the liberation of potash in clay, are the first direct proofs which have been furnished by any chemist. Though unacquainted with Professor ZierFs theory, and Professor Fuchs' experiments, when I undertook the investigation, I am bound to acknowledge that the theory I have embraced, respect- ing the liberation of potash in clay, is not a new one. Disclaiming the merit of being its discoverer, I shall feel amply rewarded by seeing these direct experimental proofs in support of this theory confirmed by the experience of other chemists. 4. Is it essential, or desirable, that clays fit for burning should contain lime ? My own experiments have been confined to clay which con- tained originally lime ; I am, therefore, not prepared to answer the first part of the question — namely, is it essential that clays fit for burning should contain lime ? The observations already made respecting the action of lime on insoluble silicates of potash and soda, however, enable me to answer the second part of the question — namely, is it desirable that such clays should contain lime V — in the affirmative. If the above explanation of the action of lime on silicate of potash is true, we can easily conceive how the addition of lime to clay, originally poor in this element, will increase the amount of soluble potash and soda. In this view of the matter I am much confirmed by an observation of Professor Fuchs of Munich, to which particular interest attaches. This eminent man, distinguished both as a good chemist and mineral- ogist, found that when felspar is moderately calcined, and in a powdered state is boiled with quick-lime and water for a short time — or even digested in the cold with quick-lime and water for a longer period — so large a proportion of potash is liberated from the constituents of felspar that, on these grounds, he recommended a process of extracting and manufacturing potash on a large scale from felspar. Professor Fuchs has shown that, under these cir- cumstances, insoluble silicate of lime and soluble carbonate of potash are formed. I would, therefore, suggest the application of quick-lime to newly burnt clay land, or the mixing of clay with lime before burning, as likely to be attended with most beneficial effects. 5. What are the characteristics of clays, of which it can be said that they are totally unfit for burning ? The chief mass of all clays, silicate of alumina, does not in itself serve as direct food to plants. Pure clays, such as pipe and porcelain clay, which almost entirely consist of silica and alumina, for this reason will be found as sterile after burning as they are in their natural state. We have seen that the accessary constituents of agricultural clays furnish the materials from which plants derive inorganic food. Of these the most important and valuable are phosphoric acid and the alkalies. As phosphoric acid is not ren- dered more soluble in burning clay, but rather the contrary, as 21 shown by the above table, we are bound to look to the alkalies as the chief fertilising substances in clays. The analyses of three different kinds of clays, from Gloucestershire, given above, as well as a great many others published by Professor Johnston, exhibit a great difference in the relative proportion of potash and soda which they contain. Whilst some of them contain considerable quantities of potash and soda, others contain but mere traces. Now, if it be true what has been advanced with regard to the fertilising substan- ces in clays, and the effects produced in burning, we cannot hesi- tate to pronounce all clays which contain no potash or soda in an undecomposed form, or mere traces, as entirely unfit for burning. Experience, I think, will prove that such clays, naturally unfertile, will not be improved in the least by burning. On the other hand, those clays which contain undecomposed insoluble silicate of potash and soda, in the shape of fragments of felspar or any other mineral, will be found the more useful after burning, I think, the more of these alkalined silicates they originally contain. 6. Can it be determined by chemical analysis whether a clay will be efficacious when burnt or not? From the preceding remarks it follows that the fertilising effects of clay mainly depend on the proportion of alkalies which it contains ; and as any good analytical chemist may determine the exact quantity of potash and soda which may be extracted from a clay, we possess the means of deciding at once whether a clay is likely to be efficacious when burnt or not. The advantages which result from a previous analytical examination become most conspicuous when we consider that the trifling expense for analysis will guard the farmers against failure and loss attending the investment of much money and labour in burning soils, which cannot be rendered more fertile by this operation. Chemistry, in this manner, I have no doubt, will be found to confer material practical benefits to those who avail themselves of its aid. It cannot be expected that every farmer should himself be a good chemist, were it desirable or necessary ; but we may justly demand of him that he should properly appreciate the labours of those engaged in chemico-agricultural researches. Without a know- ledge of the first principles of the science, however, the practical man will never be able to appreciate properly the aid which chemistry is capable of conferring on him, nor will he fully under- stand the direct bearing which chemistry exercises on many practical operations. We would therefore * recommend the study of the principles of the science as the foundation of true agricul- tural progress. 7. What are the causes of the failure attending over-burning ? W^hen clay is burnt too strong it becomes hard like stone, loses much in porosity, and does not crumble to powder on exposure to the air. To these mechanical changes, no doubt, the failure of ^2 over-burnt clay partly must be ascribed. I say only partly, because Professor Johnston has already shown that, in over- burning, the constituents of clay are rendered less soluble than they are in the natural clay. My experiments fully confirm the Professor's observations. I have further found, that over-burnt clay does not absorb so much ammonia from the atmosphere as properly burnt clay, which is easily explained by the diminished porosity, and consequently diminished absorptive power, of such clays. The cause of the failure attending over-burning, then, must be sought — 1st, In the mechanical changes clay undergoes in over-burning ; 2d, In the chemical changes which render such clays less soluble ; and 3d, In the diminished power of absorbing gases from the atmosphere. 8. Does moderately burnt clay absorb more ammonia from the atmosphere than clay in its natural state ? It will be remembered that many chemists and agricultural writers ascribe the advantages of burnt clay to ammonia, which, according to their views, is absorbed from the atmosphere by it in that state more extensively than when it is unburn t. In order to put this theory to the test, I made the following experiments with — 1. Clay from Huntstile, near Bridgewater, in its natural state, (the same as that used in the above analyses, marked No. I.) 2. Clay from the same locality moderately burnt (the same as that used in the above analyses, marked No. II.) Both portions were moistened with water, and exposed in glass beakers to the atmosphere for a period of tvvo months and twelve days, without, however, renewing the evaporated water. After that period the quantity of ammonia in each sample was determined by combustion with soda — ^lime in the usual manner. The follow- ing are the results : — (1.) Clay from Huntstile, in its natural state. 239*15 grains, on combustion, furnished 4*94 grs. of bichloride of platinum and ammonium, or 100 parts of air-dry clay contained 0-240 per cent of ammonia (NH^,b). ^ (2.) Clay from Huntstile, moderately burnt. 210*15 grs., on combustion, gave 0*36 of bichloride of platin. and ammonium, or 100 parts of air-dry clay contained 0*019 of ammonia (N H »0). The clay, when unbumt, it will be observed, furnished a much larger quantity of ammonia — the same after moderate calcination. We must, however, not conclude that unburnt clay possesses a greater power of absorbing ammonia from the atmosphere ; for the ammonia contained in the analysis is partly the result of the decomposition of nitrogenised organic matters which existed in the clay, and which were destroyed on burning. 23 At all events, the above analyses show that unburnt clay con- tains ammonia, or the elements from which ammonia is formed, in larger quantities than burnt clay. For that reason I cannot attach much value to the ammonia theory. 9. Does over-burnt clay absorb any or no ammonia from the atmosphere ? Sprengel, as has been mentioned before, thinks that in over- burnt clay no ammonia can be produced. The following experi- ment will show with what amount of confidence this doctrine is to be accepted. A portion of over-burnt clay from Huntstile, the solubility of which, as proved by the above analysis, was considerably smaller than that of properly burnt clay, was exposed to the atmosphere, moistened with water, for two months and thirteen days. The amount of ammonia was then determined in the same manner as in the preceding experiment. 219 grs. of air-dry gave 0*155 grs. of bichloride of platinum and ammonium, or 100 parts furnished only 0*008 per cent of ammonium. We thus find that Sprengel's theory is not borne out by direct experiment ; but, at the same time, we see here that the power of absorbing ammonia in over-burnt clay is considerably reduced. Moderately burnt clay will absorb double the quantity of ammonia from the atmosphere which will be absorbed by over- burnt clay under precisely the same circumstances. 10. Is ammonia found in burnt clay containing protoxide of iron, when exposed in a moist state to the atmosphere, in much larger quantities than in the same clay exposed in a dry state to the atmosphere ? In answer to this question, the following experiments were instituted : — A portion of the same clay used throughout in all the experi- ments was moderately burnt in a closed crucible, after having been previously mixed with 1 per cent of charcoal powder. The charcoal powder was mixed with the clay for the purpose of reducing the peroxide of iron in the clay to protoxide. (1.) One-half of the clay thus treated was exposed for two months and fourteen days to a dry atmosphere, in a dry state. (2.) The other half was thoroughly moistened with water, and exposed for the same length of time to the same atmosphere. The quantity of ammonia in each sample was then determined separately. (1.) Clay exposed to the atmosphere in a dry state : 182*81 grs. gave 0*28 grs. of bichloride of platin. and ammonium, or 100 grs. gave 0*17 per cent of ammonium. (2.) Clay exposed to the atmosphere in a wet state: 212*11 24 grs. of clay gave 0-33 grs. of bichloride of platin. and aramoniuro, or 100 grs. gave 0.018 per cent of ammonium. These quantities of ammonia are nearly identical. Ammonia, accordingly, is not formed, as Sprengel supposes, by the decom- position of water under the influence of protoxide of iron and the atmosphere, in a larger quantity, in which ammonia is absorbed by dry clay from the atmosphere. Thus, under no circumstance do we find ammonia in burnt clay in larger quantities than in unbumt clay. The effects of burnt clay, therefore, cannot be explained by the absorption of ammonia only. 11. What is the reason that burnt clay improves especially root and other green crops as Mr Woodward states ? Mr Woodward's observation that root-crops are particularly benefited by burnt clay also receives an easy explanation from the mode of its action, which we have explained ; for we must recollect that turnips, swedes, maiigold-wurzel, potatoes, &c., require much potash to mature their growth. It may be mentioned, in conclusion, that I have determined the whole amount of alkalies which the clay from Huntstile farm is capable of furnishing, when fused with carbonate of baryta. The quantity of potash and soda present in the clay, for the greater part in a state of insoluble silicates, I find to be : Potash=4*726 per cent, and Soda=*88 per cent. As one of the characteristics of a clay fit for burning, we have pointed out the undecomposed alkaline silicates which good clays should contain. Thus, finding the proportion of potash and soda so considerable, as in this clay, we are justified in suggesting that this clay is most likely to prove very efficacious after burning. With this theoretical speculation agrees well the fact mentioned by Mr Danger, the tenant of Huntstile farm, that by burning this clay the land is very much improved. Mr Danger says : '' Of course I can only speak to the fact. A soil which I have found quite sterile^ on which this process has been used, became totally changed^ Having thus considered each of our propositions separately, and deduced from them what appeared to us the most prominent and legitimate conclusions, we shall conclude by merely recapitu- lating the principal and most practical facts which depend on them, leaving the discriminating reader to form his own opinion of the whole subject. Summary, 1. The mechanical changes produced on clay upon burning, which by no means are unimportant^ nevertheless do not suffi- ciently explain the fertilising effects of burnt clay. 25 2. These are dependent on the chemical, as well as on the mechanical changes, both produced upon burning clay. 3. Clay after burning becomes more soluble in dilute acids. 4. The temperature used in burning clay regulates the solubility of clay ; too intense a heat renders clay, again, less soluble. 5. A temperature whereby the organic matter in clay soils is merely changed, but not destroyed altogether, should be employed in burning clay in the field. 6. On overburning, clay becomes less soluble than it is in its natural state. 7. Burnt clay contains more soluble potash , and soda than unburnt. 8. Properly burnt clay furnishes a larger proportion of soluble potash and soda than clay burnt at too high a temperature. 9. In burning clay the same effects are produced as in bare- fallow. 10. The fertilising effects of burnt clay are mainly dependent on the larger amount of potash and soda, particularly of potash, which is liberated from the insoluble silicates in the process of burning. 11. Clays originally containing much undecomposed silicates of potash and soda are best suited for burning. 12. On the contrary, those resembling in composition pure pipe and porcelain clays, and all those which contain mere traces of undecomposed alkaline silicates, are unfit for burning. 13. It is desirable that clay which is intended to be burnt should contain lime. 14. The application of quicklime to newly burnt clay land, or the mixing of clay with lime before burning, is likely to be attended with much benefit. 1 5. Burnt clay absorbs ammonia from the atmosphere. 16. Clay in its natural state furnishes more ammonia than properly burned clay. 17. Overburnt clay does not absorb so much ammonia as properly burnt clay. 18. The causes of the failures attending over-burning, are due : 1. To the mechanical changes which clay experiences in overburning, whereby it is rendered hard like stone. 2. To the chemical changes whereby the constituents of clay are rendered less soluble. 3. To the diminished porosity, and consequently reduced absorptive power of such clays. 19. Burnt clay improves especially turnips, carrots, potatoes, and other green crops, because it furnishes potash, which these crops largely require, more abundantly and more readily than unburnt clay. ON THE COMPARATIVE VALUE OF WHITE SCOTTISH AND BLACK ENGLISH OATS; AND ON THE COMPOSITION OF RICE-MEAL. From ike Journal of Agriculture, and Transactions of the Highland and Agricultural Society of Scotland, for January 1853. The comparative Value of White Scottish Oats and Black English Oats, By Dr Augustus Voelcker, Professor of Chemistry in the Eoyal Agricultural College, £)irencester. — White oats are generally considered more valuable than black, and Scottish, in particular, are usually preferred to those grown in England, it being the opinion of practical men that the former possess greater nutritive properties than the latter. The direct proof, however, that this is really the case, as far as I am aware, has not been fur- nished; at all events, it has not been shown to what extent the feeding properties of the two varieties differ. With a view to supply this deficiency, I examined, some time ago, specimens of white Scottish and black English oats, and am enabled by the results of this examination to furnish a direct and positive proof of the correctness of the opinion above stated. Black oats can frequently be obtained in the market at a much cheaper rate than the white Scottish ; but as the first are inferior to the latter in feeding value, as will be shown presently, the ques- tion naturally suggests itself. Is it more economical to buy white Scottish oats at a higher, or black English at a lower price? An answer to this question has a direct practical bearing, and I shall therefore endeavour to point out how far the difference in the cost price of both is compensated by the greater nutritive properties of the Scottish sample. The commercial value of different kinds of wheat, barley, or other grains of the usually cultivated cereals, is influenced in a great measure by the relative proportions of bran and flour, which different samples of the same grain furnish to the miller. The various kinds of oats, especially, furnish greater differences in the proportions of husk and meal than probably any other grain. Whilst some yield as much as three-fourths of their weight of oat- meal, others yield only 10 parts of meal from 16 of grain; and some samples of inferior quality produce but one-half their weight of oatmeal. My attention was therefore naturally first directed to the deter- mination of the relative proportions of husk and meal, which the two specimens of white Scottish and black English oats yielded. 1. In the white Scottish I have found in 100 lb. — Oatmeal, . . . . . 1\\\h. Husk, ..... 28| ... 100 ... 2. In black English oats the proportion of husk and meal in 100 lb. was as follows : — Oatmeal, ..... 66^ lb. Husk, ..... 33| ... 100 ... 4 WHITE SCOTTISH AND BLACK ENGLISH OATS. 100 lb. of Scottish oats thus yielded 5^ lb. more meal than the black English. The former is thus decidedly more valuable than the latter. Oats, however, are generally sold by measure, and not by weight. The weight of a bushel of oats, it is well known, is subject to great variations, some kinds being considerably heavier than others. In order to draw a fair comparison between the relative value of the two varieties of oats, it was necessary to determine the weight of a bushel of each, and to calculate from their relative weights the yield of meal which each variety furnished per bushel. One bushel of white Scottish oats was found to weigh 42 lb. ; the bushel of black English oats weighed only 37^ lb. The price of the former at Cirencester was 20s. per quarter. English black oats were offered at Cirencester for 15s. 6d. per quarter. Let us now calculate from these data how much oatmeal these two varieties furnished respectively. 1. White Scottish Oats.— 100 lb. yielded 71^ lb. of oatmeal: 1 quarter accordingly produces 240^ lb. of oatmeal, for — Oats. Meal. The weight of 1 quarter oats. Meal. 100 lb. : 714 lb. = 8 X 42 : x . x = 240^ lb. 240J lb. of Scottish oatmeal are thus obtained at an expense of.£>l. 2. Black English Oats.— 100 lb. yielded 66^ lb. of oatmeal. 1 quarter will thus furnish 198} lb., for — Oats. Meal. The weight of 1 quarter oats. Meal. 100 lb. : 66i lb. = 8 x 37^ : a; . « = 198| lb. 198f lb. of English oatmeal, according to the above-mentioned price, will cost 15s. 6d. ; or, for £1, 256^ lb. of oatmeal can be obtained. Thus, by expending £1 for oatmeal, 16J lb. more meal can be got, if black English oats are bought at the price of 15s. 6d., the cost of white Scottish oats being £1 per quarter. Or for Is. I can get 12 lb. of meal prepared from white Scottish oats ; whilst for Is. I can get 12 lb. 13 oz. of meal prepared from black English oats. Supposing both kinds of oatmeal to possess equal nutritive and commercial value, according to these determinations, a saving of about Is. 4d. for every quarter would be effected by preferring the black oats to the white. Such a supposition, however, is not admissible, since it is well known that the relative nutritive value of different samples of oatmeal is subject to considerable variations. The nutritive value of different samples of grain, so far, at least, as it is dependent on their power of producing muscle, is usually estimated by the greater or smaller proportion of protein com- pounds which they yield on analysis. It appears to me, there- fore, necessary to determine by analysis the percentage of these valuable compounds in the oatmeal prepared from the white and the black oats. COMPOSITION OF RICE-MEAL, OR RICE-DUST. 5 a. 18.31 grains of oatmeal, from white oats, dried at 212° F., gave 6.88 chloride of platinum and ammonium, or 2.59 per cent of nitro- gen, which is equal to 14.743 per cent of flesh-forming substances. h. 13.60 grains of oatmeal, from black English oats, dried at 212° F., gave 4.83 of chloride of platinum and ammonium, or 2.230 per cent of nitrogen, equal to 13.94 per cent of flesh-forming sub- stances. We thus see that Scottish meal possesses greater nutritive value than the meal prepared from black English oats. It is true, the difl*erence in the proportion of flesh-forming principles in both kinds of oatmeal is not very great, but still the superiority of the Scottish sample in this respect appears to us more than sufficient to compensate for the greater price at which the white oats were bought. Apparently the diflerence in favour of the black English oats is 4s. 6d., but we have seen that it actually amounted merely to Is. 4d. per quarter, supposing both kinds to possess equal nutri- tive value — which, however, is not the case. Taking the greater nutritive value of the white oats into con- sideration, we are inclined to consider it more economical to pay £1 for white than 15s. 6d. for black oats. It will hardly be necessary to mention that the above observa- tions apply merely to the two samples of oats which have been examined, and not in general to all kinds of Scottish and English oats. The Composition of Bice-Meal or Rice-Dust, By Dr Augustus VoELCKER. — Rice-meal, rice-dust, or rice-refuse, which is obtained in cleaning rice for our market, consists of the husk and external layers of rice, together with fragments of the grain itself, and some accidental foreign impurities. This refuse has been used by several practical feeders with advantage in the feeding of stock. Whenever it can, therefore, be obtained at a moderate price, rice- dust will be found a valuable article of food, provided it is given to cattle judiciously along with other more substantial food. We fear, however, that this refuse is sold often much above its real value, and it appeared to us necessary, for this reason, to deter- mine its value by analysis. From the manner in which rice-dust is obtained, we cannot expect it to be of uniform composition, but the following analyses may be taken as representing the com- position of a fair average sample of unadulterated rice-dust. The sample analysed was offered for sale at £3, 12s. 6d. in London, or, with expenses for carriage to Cirencester, would have cost £4, OS. 6d. per ton. a. Percentage of water, — Dried in the water-bath, it lost 12.019 per cent of water, or about the same quantity which common flour loses on drying. h. Percentage of ash. — Burnt in a platinum capsule, a whitish ash was left behind, amounting to 13.49 per cent of the whole weight of the meal in its natural state. The greater portion of the ash, namely 9.83 per cent, consisted of insoluble matters, chiefly carbonate of lime and silicic acid, with some phosphates ; the smaller portion, namely 3.66 per cent, was soluble in water, and consisted of soluble salts, chiefly alkaline chlorides. c. Percentage of 'protein compounds. — The proportion of flesh- forming substances in rice-dust was calculated from the percentage of nitrogen, obtained by burning the substance with soda-lime, according to Will and Varrentrapp's methods. In two combus- tions, precisely the same quantity (6.687 per cent) of protein com- pounds was found. d. The oil in rice-dust was determined by digesting the sub- stance repeatedly with ether, in which the oil is readily soluble. On evaporation of the several ethereal extracts, a yellow sweet oil remained behind, which amounted to 5.610 in the natural sub- stance. 6. Woody fihre^ starchy and sugar were determined in the usual manner. The following numbers represent the composition of this sample of rice-meal or rice-dust :— ' Water, . . . . Woody fibre, containing insoluble inorganic matters, 9.83, Starch, gum, and sugar, Protein compounds, or flesh-forming constituents, Fatty matters, .... Soluble saline substances, 12.019 46.500 25.524 6.687 5.610 3.660 100.000 These analytical results suggest to us the following observa- tions : — 1 . That this refuse is very rich in oily or fatty matters. It con- tains, indeed, as much fatty substance as the best oats, but is inferior in this respect to Indian corn, which contains rather more oil. Rice-dust, for this reason, is well adapted for the laying on of fat upon animals. 2. In rice itself, according to Payen, only 0.8 per cent of fatty matters occur ; and we find thus, that, as in most other kinds of grain, the fat is chiefly deposited in the exterior part of the seed. 3. Harsford found in the grain of rice 6.27 per cent of protein compounds in its ordinary, or 7.4 per cent in its dry state. In rice-dust I have found nearly the same quantity, namely, 6.687 per cent, in its natural state, or 7.600 per cent in its dry state. As far as the power of producing muscle is concerned, rice meal or dust appears to be fully as valuable as the grain of rice itself. 4. Eice-dust contains nearly half its weight of woody fibre, which possesses little or no value as a feeding substance. The COMPOSITION OF RICE-MEAL, OR RICE-DUST. 7 exact quantity amounted to 46.500, which, added to 12.019 of water, gives 58.519 per cent of useless matters. It has already been mentioned that the price of this refuse per ton, delivered at Cirencester, was £4, 5s. The practical question, which chiefly interests the farmer, is. Will it pay to buy rice-dust at this price, in preference to barley, oats, Indian corn, or any other kind of corn ? We should say decidedly that it would not pay at this price. Crushed oats of good quality, which can be had at about £6, 6s. to £7 per ton, contain the same quantity of fatty matters as rice-dust, but at least double the quantity of flesh- forming constituents, and also once as much starch, gum, and sugar, as rice-dust. Oats appear, therefore, at least twice as valuable as this refuse ; and the price of the latter should, for this reason, not be more than about £3 to £3, 5s. Barley-meal is not quite so nutritious as oatmeal, but, taking into consideration that barley-meal does not contain so much husk as oats, and comparing its composition with that of rice-dust, we think that barley-meal may be considered as possessing once as much value, as a feeding substance, as rice-dust, without commit- ting any great practical error. Barley-meal, however, can be had at £7 per ton. ON THE COMPOSITION GEEEN EYE AND EAPE. From the Transactions of the Highland and Agricultural Society of Scotland, for July ]85L *^0N THE COMPOSITION OF GREEN RYE AND RAPE. By Da Augustus Voelcker, Professor of Chemistry in the Royal Agricultural College, Cirencester. In a paper of mine on the composition of green food, which ap- peared in the July number of this Journal for 1853, analyses of most articles of food which are used in a green state will be found. I have not stated, however, in that paper the composition of green rye, as I had not an opportunity of obtaining the material for analysis in a perfectly fresh condition at the time when the other analyses were made. In order to supply this deficiency, I have this spring submitted young rye to a detailed analysis, the re- sults of which may not be without interest to the agricultural reader. The analysis of rye is followed by detailed analyses, both organic and inorganic, of rape. Since the publication of the general composition of green rape in the paper referred to above, my attention was directed by several good practical farmers and sheep-breeders in this neighbourhood, to the remarkable fattening properties of green rape, which, I am told, render it a most valu- able food for sheep. This circumstance induced me again to examine green rape. As the chief object of my previous analyses was to ascertain its flesh-forming properties, direct determinations of the fatty matters, and other substances which are employed in the animal economy in the laying on of fat, were omitted. In the subjoined proximate analyses, on the contrary, particular care was bestowed on the direct and accurate determination of the fat-pro- ducing constituents of green rape. At the same time, the ulti- mate composition of green rape has been ascertained as well as that of its ash. It is much to be regretted that we possess so few^ detailed organic analyses of agricultural products, on the accuracy of which dependence can be placed. Most analyses of this sort were made at a time when organic chemistry was quite in its in- fancy. The analytical processes with which chemists were then acquainted necessarily were very imperfect, and consequently ill calculated to furnish accurate results. More correct proximate analyses of most kinds of agricultural produce are thus much required. With the publication of such analyses, a clear descrip- tion of the method which has been followed in determining the different organic constituents should never be omitted, for the publication of analytical methods will often induce others to engage in similar researches. At the same time, it will tend much to the suppression of analyses made by improperly qualified persons ; and it may likewise lead to more accurate or simple plans of operation. Before stating, therefore, the results of the analyses of green rye and rape, I shall briefly describe the method which I 4 COMPOSITION OP GREEN RYE AND RAPE. employed in the determination of the various constituents enter- ing into the composition of these two crops. 1. Determination of water and ash. — For the determination of water 1000 grs. of the fresh substance were taken. The weighed substance was first dried in the air, subsequently at the top of a water-bath, and finally in a hot-air bath, at a temperature of 220°rahr. The loss in weight, by calculation, gave the per-centage of water. Two separate portions of the dried substance were then re- duced to ash, at a moderate heat, over a gas-burner, in a platinum capsule. 2. Determination of cellular fihre^ insoluble protein compomids^ and insoluble inorganic salts attached to the fibre. — The separation of all the soluble constituents from the insoluble was eflfected in the following manner : — For analysis 1000 grs. of the fresh rye or rape were weighed out at the same time at which the respective portions for the water-determination were weighed. I am particular in stating this, because the amount of water in the leaves and other parts of green plants varies from day to day, for which reason the weigh- ings for the different determinations ought to be made all at the same time. In order to secure a fair average sample, it is ad- visable to cut the fresh plant, or that part of the plant which is to be analysed, in one or two-inch pieces, and to mix together a quantity of such bits, sufficient for all the separate determinations. If this precaution is neglected, on adding up the results of the analyses there will be found almost always either an excess or a deficiency. The 1000 grs. of the fresh substance were mashed in a porcelain mortar to a fine pulp, with the addition of a small quantity of distilled water. The preparation of a fine pulp, in the case of grass or leaves, is a tedious process, which succeeds best by using no more water than is necessary to prevent portions of the sub- stance being thrown out of the mortar by agitation with the pestle. When sufficiently fine, about four or five ounces of distilled water were added, and the pulp digested with it for about half an hour. After that time the liquid, containing in solution gum, sugar, soluble albumen, and other soluble matters, was strained through a piece of fine linen, previously wetted with distilled water, and tied over a large glass beaker. The impure cellular fibre on the linen was squeezed in the cloth as tightly as possible, then transferred back in the mortar, and thoroughly agitated with the pestle, a small quantity of water being added at the same time. The insoluble portion was then again digested with four to five ounces of distilled water for half an hour, and the liquid strained through the linen cloth as before. The same opera- COMPOSITION OF GREEN RYE AND RAPE. D tion was repeated a third time ; the cellular fibre on the cloth by that time was nearly white, and, after a few washings with water, imparted nothing soluble to water. Thus washed clean, the im- pure fibre was dried in the water-bath, and its weight ascertained. A portion of the dried impure fibre was subsequently reduced to ash in a platinum capsule, and by this means the proportion of insoluble inorganic matters attached to the fibre was determined. The ash of the fibre consisted principally of carbonate and phos- phate of lime, and contained, likewise, some sulphate of lime, magnesia, and siHca. Another weighed portion of the finely -powdered and dried impure fibre was employed for a nitrogen determination. The amount of nitrogen was ascertained in the usual way, by com- bustion with soda-lime, and, by calculation from the amount of nitrogen, that of the insoluble protein compounds contained in young rye and rape were determined. A third portion of the impure fibre was digested with alcohol and ether, in order to deprive it of any remains of fatty matter which may have been attached to it. The amount of insoluble protein compounds and inorganic matters thus obtained, being deducted from the impure fibre, exhausted with alcohol and ether, furnished by calculation the per- centage of pure cellular fibre. 3. Determination of Soluble Albumen. — The united liquids which passed through the linen cloth were raised to the boiling-point in a glass beaker, when a considerable quantity of greenish-coloured flakes of coagulated albumen was separated. These flakes were allowed to settle for twenty-four hours. After that time the supernatant liquid, now become clear, was passed through a weighed filter, on which the coagulated albumen was also col- lected. The albumen was washed on the filter with distilled water, dried at 212° Fahr., then digested with alcohol and ether, and finally dried in the water-bath until it ceased to lose weight. The greenish colour of the albumen is due to some chlorophyll, the greater part of which is removed by digestion in alcohol and ether. A few drops of acetic acid added to a portion of the liquid from which the albumen had been separated by boiling and filtration, produced no change, and thus showed the absence of casein in the juice of the plants under consideration. 4. Determination of gum^ pectin^ and salts^ insoluble in alcohol. — In the liquid from which soluble albumen was separated by boiling and filtration, gum, pectin, sugar, and soluble inorganic salts, besides traces of other less important compounds, the quan- titative determination of which was omitted, were present. The separation of the sugar and salts soluble in alcohol from gum, pectin, and salts insoluble in alcohol, was effected as follows : 6 COMPOSITION OF GREEN RYE AND RAPE. — The liquid separated from the albumen was evaporated on the water-bath to a thickish syrup. On addition of alcohol to this syrup, pectin, and gum, with some inorganic salts, were thrown down. In order to remove any traces of adhering sugar, the pre- cipitate was repeatedly boiled out with alcohol, until the solvent ceased to take up any perceptible quantity of soluble substance from the precipitate. The insoluble residue was then transferred to a weighed porcelain crucible, dried in the water-bath and weighed. The amount of inorganic salts contained in it was ascertained by reducing it to ash, which being deducted from the weight of the impure gum and pectin, gave the proportion of pure gum aud pec- tin. The salts soluble in alcohol were found to consist principally of chlorides of sodium and potassium. 5. Determination of Sugar. — The alcoholic liquids obtained in determining the gum and pectin were introduced into a retort, and the alcohol distilled off in the water-bath. The residue in the re- tort was transferred to a porcelain crucible, and, after evapora- tion on the water-bath, dried at 2.30° F., until it ceased to lose weight. It being exceedingly difficult to expel the water com- pletely from the sugar at 212° F., a somewhat higher temperature was employed for drying. In the sugar thus obtained, a consider- able proportion of inorganic salts, soluble in alcohol, was present. On burning this impure sugar, the inorganic salts were left be- hind in the form of a white ash, the weight of which being deduct- ed from that of the impure sugar, gave the proportion of pure sugar. 6. Determination of Fatty Matters. — Like all vegetable produc- tions, green rye and rape contain appreciable quantities of oily and fatty matters. Their quantitative determination was effected by repeatedly digesting 100 grains of the dried and powdered substance in ether, a liquid which readily dissolves all fatty mat- ters. The ethereal solutions were passed through a filter, upon which the powdered substance, boiled out several times with ether, was washed with this solvent, in order to remove all traces of ad- hering fat. The greater part of the ether employed in this deter- mination was obtained back again by distillation of the mixed ethereal liquids at a moderate temperature ; the ether which passed over first into the receiver was collected by itself, and in this way a much stronger ether than the commercial article was obtained. The residue in the retort, evaporated to dryness, was found to con- tain some sugar, which had been dissolved with the oil by the alcohol, usually contained in commercial ether. In order to obtain the oil and fatty matters free from sugar, a small quantity of the strong ether, prepared as described by fractional distillation, was added to the mixture of sugar and fatty matters. The sugar was left insoluble, and the oil and fat dissolved in the ether. On evapo- ration of the ether, the oil was left behind quite pure ; and after COMPOSITION OF GREEN RYE AND RAPE. 7 drying on the water-bath, its weight was determined on the balance. It is essential to examine carefully the residue which is left on evaporation of the first ethereal liquids, for commercial ether always contains some water and alcohol, which both dissolve a small proportion of sugar from the vegetable substance which is treated with such ether. 7. Determination of the whole amount of protein compounds, or flesh-forming constituents. — In order to ascertain how far the direct determination of albumen, and that of the insoluble protein compounds obtained by combustion, agreed with a total determi- nation of the protein compounds, about 20 grains of the dried sub- stance were burned with soda-lime in a combustion-tube ; and the amount of nitrogen obtained, by following the method of Will and Varrentrapp, being multiplied by 6 J, gave the proportion of pro- tein compounds in young rye and rape. Having thus described briefly the method according to which the organic analyses were executed, I shall now proceed to state the results obtained in the analyses of both green foods. I. COMPOSITION OF GREEN RYE. Water. — (1.) Dried in the air-bath, at 220° F. ; green rye lost 79.58 per cent of water. (2.) In another determination, 79.23 per cent of water were obtained ; on an average, green rye thus contained 79.405 per cent of water. (3.) Another sample, taken from the field some days after the two preceding ; 75.423 per cent were found. Ash. — (1.) 250 grains of fresh rye, on burning, gave 4.44 grains of ash, or 1.778 per cent; or 8.633 per cent of ash in the dried substance. (2.) In the sample of rye, which was analysed some days after the preceding, 1.57 per cent of ash were found. This ash was dis- tributed amongst the different constituents of rye as follows : — Ash in cellular fibre, . . . . . .418 „ gum and pectin, ..... .572 „ sugar, ...... .368 „ albumen, . . . . . . .180 1.538 These separate determinations of ash agree as closely as possible with the total determination of ash. Protein compounds, — (1.) By* separate determinations there were found — Soluble albumen, . . 2.357 with .3771 of nitrogen. Insoluble protein compounds, . .736 „ .1178 „ 3.093 „ .4949 (2.) In the sample taken some days after the preceding, the 8 COMPOSITION OF GREEN RYE AND RAPE. total proportion of nitrogen was found, in two determinations, on an average, at .442 per cent, equal to 2.762 per cent of protein compounds. By separate determinations there were found — Soluble albumen, . . 1.810 with .289 of nitrogen. Insoluble protein compounds, . .894 „ .143 „ 2.704 „ .432 „ The two latter determinations agree well with the total amount of protein compounds, as ascertained by combustion. According to these determinations, the general composition of both samples of green rye may be represented as follows : — No. I. No. II. Water, • . . . . 79.230 75.423 Inorganic matters (ash). 1.778 1.538 Nitrogenised substances (flesh-forming con- stituents), .... 3.093 2.704 Non-nitrogenised substances (fat and heat- producing matters), 15.899 20.335 And that of rye in a dry state — 100.000 100.000 No. I. No. II. Nitrogenised substances, capable of produc- ing flesh, .... 14.891 11.002 Substances free from nitrogen, and fitted to support respiration, and for the forma- tion of fat, .... 76.476 82.739 Inorganic matters (ash), . . 8.633 6.259 100.000 100.000 It will appear that the first sample, although containing more water, is richer in flesh-forming constituents than the second. In the more succulent condition, rye thus appears to contain especially more soluble albumen than at a more advanced state of maturity ; we may therefore infer from this fact, that it is not a good plan to let the green rye remain too long on the ground before eating it off by sheep. The following tables exhibit the results of the detailed proxi- mate analyses of both samples of rye, in its natural state and in a perfectly dry state : — PROXIMATE COMPOSITION OF GREEN RYE, NO. I. In natural state. Calculated dry. Water, ..... 79.405 — Solid substance, 20.695, consisting of— Cellular fibre, . 8.579 41.454 Soluble albumen. 2.357 11.444 Insoluble protein compounds, . .736 3.775 Fatty matters, . .892 4.332 Gum and sugar. 6.253 30.362 Inorganic substances (ash), 1.778 8.633 100.000 100.000 COMPOSITION OF GREEN RYE AND RAPE. PROXIMATE COMPOSITION OF GREEN RYE, NO. IL Water, . Cellular fibre, . Ash united with fibre, . Insoluble protein compounds, Soluble albumen, Gum and pectin, Salts, insoluble in alcohol, Sugar, . Salts, soluble in alcohol, Fatty matters, . 100.000 100.000 A comparison of the composition of green rye with that of Italian rye-grass will show that both possess about equal nutritive value. Green rye, it thus of clover as a feeding-stuff. n natural state. Calculated dry 75.423 — 10.488 42.674 ,418 1.701 .894 3.688 1.811 7.369 4.449 18.102 .572 2.327 4.685 19.062 .368 1.499 .892 3.628 appears, is inferior to the better sorts II. — COMPOSITION OP RAPE. Water. — (a.) In leaves. — The proportion of water varies to some extent in rape, as will be seen by the following determina- tions, which indicate the amount of water in different samples of rape-leaves, taken from the field at different periods : — 1. Per-centage of water, 2. ^^ ^ 3. _ 4. 5. ^^ _ 6. ^^ _ 7. 88.99 86.90 88.72 87.20 87.05 85.25 85.52 Average, . 87.09 (6.) In stalks. — In two different portions of the stems of rape the amount of water was — I. II. Per cent, . . 94.77 90.08 The stems are thus more watery than the leaves. (c.) In roots. — Average. 92.42 I. 78.54 II. 86.37 Average. 82.45 Per-centage of water, The first determination was made with a sample of the more lig- neous older roots, the second with the more tender young roots. Ash. — (a.) In leaves. — The proportion of ash in different samples of fresh leaves was found as follows : — 1. Per-centage of ash, 2. ^ ^ 3. ^ ^ 4. 6. ^ 7. ZL Z 1.27 1.60 1.63 1.43 1.60 2.17 1.91 Average, i.e 10 COMPOSITION OF GREEN RYE AND RAPE. (6. In stalks. — I. II. Average. Per-centage of ash, 1.25 1.15 1.20 3.41 ^^^ 21.31 3.87 ,,^ 24.19 3.49 ^^„ 21.81 3.54 22.12 4.02 ..^ 25.12 3.45 -,*. 21.56 (c.) In roots. — Per-centage of ash, . 1.84 1.66 1.75 Protein compounds. — (a.) In leaves. — The proportion of pro- tein compounds was determined by multiplying the per-centage of nitrogen, as ascertained by combustion with soda-lime with 6J. According to the periods of gathering, the per-centage of nitrogen in the leaves appears to vary to some extent. The following are some of the results obtained by combustion : — 1. Per-centage of nitrogen in dry leaves, 3.31 — equal to 20.68 protein compounds. 2. ^^ _ " " 3. _ _ 4. _. 6. _ _ 6. _ _ Average, 3.58 22.37 .^ (6.) In stalks. — 1. Per-centage of nitrogen in dry stalks, 1.14 — equal to 7.12 protein compounds. 2. ^ ^ 1.00 _ 6.25 3. Average 1.07 — 6.69 — The stems are thus far less nutritious than the leaves. (c.) In roots. — 1. Per-centage of nitrogen in dry roots, 1.72— equal to 10.76 protein compounds. 2. -^ ^ 1.86 _ 11.62 ^ 3. Average _ ^ 1.79 ^^ 11.19 According to these diflferent determinations, the general average composition of the leaves, stalks, and roots of fresh rape may be expressed as follows : — Water, .... Nitrogenised substances (flesh-forming consti- tuents), Non-nitrogenised matters (capable of producing fat, and fitted for support of respiration). Inorganic matters (ash), And that of the dried portions of rape : — Nitrogenised substances (flesh-forming consti- tuents), . . . , Substances free from nitrogen (heat and fat- producing matters), Inorganic substances (ash), 100.00 100.00 100.00 Rape-leaves contain a considerable proportion of sulphur and phosphorus in a peculiar state of organic combination. I there- Leaves. 87.09 stalks. 92.42 Roots. 82.45 2.88 0.51 1.96 8.37 1.66 5.87 1.20 100.00 13.84 1.75 100.00 100.00 Leaves. Stalks. Roots. 22.37 6.69 11.19 64.78 12.85 77.48 15.83 78.84 9.97 COMPOSITION OP GREEN RYE AND RAPE. 11 fore suggested to my friend and pupil, Mr Faber, the propriety of determining the amount of sulphur and phosphorus in rape, and am also indebted to him for the subjoined ultimate organic ana- lyses, and the ash analyses of rape-leaves. In two different samples of rape the per-centage of sulphur and phosphorus was found for the dry substance : — I. II. Average. Sulphur, . .79 .87 .83 Phosphorus, . .84 .73 .78 The dry leaves thus contain nearly one per cent of sulphur, and an equal amount of phosphorus in organic combination. ULTIMATE ANALYSES OP RAPE-LEAVES. The samples analysed, on an average, contained 9.20 per cent of ash, and contained in 100 parts — Hydrogen, 5.80 Oxygen, 38.32 Nitrogen, 4.02 Sulphur, .83 Phosphorus, .78 Ash, 9.20 100.00 In the following table the results of the detailed proximate analyses of rape in a fresh and in the dried state are contained : — Water, .... Soluble albumen, Insoluble protein compounds. Cellular fibre, Inorganic matters, attached to the fibre, Gum and pectin, Salts insoluble in alcohol, Sugar .... Salts soluble in alcohol. Fatty matters, with a little chlorophyll. tained in 100 parts- Potash, Chloride of potassium, Chloride of sodium, Lime, Magnesia, Oxide of iron, Sulphuric acid, Phosphoric acid, Soluble silica. Carbonic acid, Sand, Charcoal and loss, In natural state. In dry state. 87.050 — 1.640 12.664 1.493 11.529 3.560 27.490 .432 3.335 1.729 13.351 .990 7.645 2.218 17.622 .186 1.435 .649 5.016 99.947 99.587 laboratory by Mr Faber, co • After deduction of carbonic acid, sand, &c. 31.51 38.42 5.88 7.17 .82 1.00 16.97 20.69 1.58 1.93 1.27 1.55 12.54 15.29 9.40 11.46 2.04 2.49 12.78 ) 4.32 J .89 — 100.00 100.00 12 COMPOSITION OF GREEN EYE AND RAPE. These analytical results give rise to several observations : — 1. It will be seen that rape is much more nutritious than green rye, and contains as large a proportion of flesh-forming constitu- ents as the best kinds of food which are used in a green state. 2. But not only is rape rich in protein compounds, but it con- tains also a considerable quantity of oily or fatty matters. The fatty matters extracted from rape by ether are semi-fluid, green of colour, and possess a smell resembling the oil of rape-seed, with- out being, however, so disagreeable as rape oil. It will be observed that the fresh leaves contain of these fatty matters more than half a per cent, and the perfectly dry substance about five per cent. So large a proportion of fatty matters, as far as I know, does not occur in any other green food. The occurrence of so considerable a quantity of fatty matters explains at once, in an intelligible manner, the high fattening properties which distinguish rape as a sheep-feed. 3. Rape removes from the soil much potash, and next to it lime, sulphuric and phosphoric acid, whilst, at the same time, the total amount of inorganic constituents, or the ash of rape, is large. It is for this reason that rape requires to be grown on good land, or, at all events, on land in a moderate state of fertility. In poor soils rape never comes to anything, and it is not worth the trouble of cultivating. On land of moderate fertility, or on good rich land, an occasional crop of rape, I am inclined to believe, would supply the farmer with a larger amount of feeding materials than is affbrded in a crop of turnips grown under the same circum- stances. Weight for weight, rape is richer in flesh-forming con- stituents, and especially in fatty matters, than turnips ; and as a crop of rape per acre is often heavier than- a turnip-crop, the cul- tivation of rape, wherever it is advisable and admissible to intro- duce it, can be confidently recommended. ON THE COMPOSITION OF THE PARSNIP AND WHITE BELGIAN CARROT By Dr. AUGUSTUS VOELCKER, PROFESSOR OP CHEMISTRY IN THE ROYAL AGRICULTURAi:. COLLEGE, CIRENCESTER. LONDON: MDCCCLIII. FROM THE JOURNAL OF THE ROYAL AGRICULTURAL SOCIETY OF ENGLAND, VOL. XIII., PART II. ( 3 ) ON THE COMPOSITION OF THE PARSNIP AND WHITE BELGIAN CARROT. The parsnip has been analysed by Crome and the carrot by Hermbstadt. Both analyses, however, having been made at a time when the analytical processes with which chemists were acquainted were little calculated for giving accurate results, are necessarily very imperfect. They do not convey, there- fore, a correct idea of the true composition of these roots. The cultivation of both, especially that of the carrot, is gain- ing ground from year to year. It appeared to me, therefore, desirable to replace the former imperfect analyses by others, in which advantage has been taken of the more refined and accurate methods of investigation with which modern chemistry has made us acquainted. The parsnips and carrots analysed were grown on the farm attached to the Royal Agricultural College, in the calcareous, rather stony, and by no means deep soil. Carrots, as well as parsnips, succeed best in a deep, well-pul- verized, loamy ground, but in a shallow, stony soil they scarcely reach half the size as when grown on a deep and sufficiently porous loam. The soil in the neighbourhood of Cirencester on the whole is not favourable to the growth of these roots, it being, in most instances, too stony and too shallow. The roots for this reason remain comparatively small, and 18 tons per acre are deemed a good average crop of carrots in this part of the country. Before stating the results of the analysis of parsnips and carrots, I shall briefly describe the method which I followed in determining the various constituents entering into the CQmposition of both roots. 1. Determination of Water and Ash. — The quantities of water and ash in the parsnip and carrot were determined by drying a a2 4 On. the Composition of the weighed portion of the roots, at first in the air, subsequeptly at a gradually increased temperature, and finally in the water- bath at 212° "F. The loss in weight by calculation gave the percentage of water. The dried substance was then burned in a platinum capsule over a gas -lamp at a very moderate temperature. On account of the large proportion of alkaline salts in carrots and parsnips their ashes fuse readily. It is necessary, therefore, to apply in the preparation of these ashes but a moderate temperature, be- cause too intense a heat has the effect of fusing them. The fusing salts surround particles of carbonaceous matter, and pre- vent their complete dissipation by fire by keeping out the atmospheric oxygen. In order to obtain a fair average sample for the water and ash determinations, a whole root was cut into thin slices, from which a portion was taken for analysis after having been well mixed together. 2. Determination of Cellular Fibre ^ insoluble Protein Compounds^ and insoluble Inorganic Salts, attached to the Cellular Fibre. — By a longitudinal cut a root was divided into two halves. One half was reduced into a homogeneous pulp by grating it on a fine grater. Of this pulp 1000 grains were digested with some cold distilled water, and the liquid, containing in solution gum, sugar, soluble casein, and other soluble matters, after some time was strained through a piece of fine linen. The impure cellular fibre remaining on the linen was washed with cold distilled water until a drop of the washings ceased to leave a perceptible stain, and evaporated on a piece of platinum foil. When washed clean the impure fibre was dried in the water-bath, and its weight ascertained. A portion of the dried impure cellular fibre was burned sub- sequently in a platinum capsule, and by this means the propor- tion of insoluble inorganic matters attached to the fibre was ascertained. Another weighed portion of the finely-powdered and dried impure fibre was burned in a combustion tube with soda-lime, and the proportion of insoluble protein compounds contained in parsnips and carrots, and obtained in the analysis with the im- pure cellular fibre, was determined by calculation from the per- centage of nitrogen furnished by the combustion of the impure fibre with soda-lime. By deducting the amount of insoluble protein compounds and inorganic matters thus obtained from the amount of impure fibre the percentage of pure cellular fibre was ascertained. 3. Determination of Starch. — The milky liquid which, in the case of parsnips, passed through the linen was mixed with the Parsnip and White Behjian Carrot. 5 washings of the fibre, and allowed to settle in a glass beaker for 24 hours. After that time the starch, which rendered the water milky, was completely deposited at the bottom of the beaker. The supernatant clear liquid was carefully passed through a previously dried and weighed filter, into which the starch was also transferred from the beaker. Being well washed with distilled water, it was first dried between blotting-paper, and finally in the water-bath at 212° F., and then weighed. Carrots, at least those examined, do not contain any starch, and the watery solution passing through the linen can therefore be heated at once for the determination of casein. 4. Determination of Casein. — The liquids from which the starch was separated by the process just mentioned were heated to the boiling point in a glass-beaker. Not the slightest precipitate was produced on boiling, thus proving the total absence of soluble albumen, both in the carrot and in the parsnip. A few drops of acetic acid were then added to the boiling liquid, when a copious flaky precipitate of casein was formed. This precipitate of casein was allowed to settle for 24 hours. After that time the clear liquid above it was passed through a weighed filter, on which the casein was also collected. The precipitate was washed with distilled water as long as anything was dissolved, and then dried at 212° until it ceased to lose in weight, 5. Determination of Gum^ Pectin, and Salts insoluble in Alcohol. — The solution separated from the casein was evaporated on the water-bath to a thickish syrup, which was treated with strong alcohol to throw down pectin and gum. The gum, pectin, and salts insoluble in alcohol thus precipitated were boiled repeatedly with alcohol in order to remove any traces of adhering sugar. When washed quite clean with alcohol, the residue was trans- ferred into a weighed porcelain crucible, dried at 212 F., and weighed. On burning, gum and pectin were dissipated, and the salts insoluble in alcohol were left behind, which, being deducted from the weight of the impure gum and pectin, gave the proportion of pure gum and pectin. 6. Determination of Sugar. — The alcoholic liquids obtained in determining the gum and pectin were introduced into a retort, and the alcohol distilled off in the water-bath. The residue in the retort was transferred into a porcelain crucible, and, after perfect evaporation on the water-bath, dried at 230° F., until it ceased to lose in weight. The drying process of the sugar is exceedingly tedious, as it takes a long time to expel the water completely from the sugar. 'J'he sugar thus obtained contains a considerable proportion of 6 On the Composition of tite inorganic salts, soluble in alcohol. The weight of the latter was determined by exposing the impure sugar to a strong heat, at which the organic part was destroyed, and the inorganic matters were left behind in the form of a white ash. The weight of the ash deducted from that of the impure sugar gave the pro- portion of pure sugar. 7. Determination of Fatty Matters. — In order to ascertain the proportion of oil or fatty matters contained in carrots and parsnips 100 grains of the dried roots were repeatedly digested with ether, which readily dissolves all fatty matters. The ethereal solu- tions were passed through a filter, upon which the powdered sub- stance, now exhausted with ether, was washed with this solvent in order to remove all traces of adhering fat By distillation in a retort the greater part of the ether of the ethereal extracts was obtained back again. 'J he residue in the retort, evaporated to dryness, was found to contain some sugar, which had been dis- solved with the oil by the alcohol usually contained in ether. The oil was separated from this sugar by digestion with a small quantity of anhydrous ether, free from alcohol. On evaporation of the ether the oil was left behind quite pure, and its weight determined. It is essential to examine carefully the residue which is left on evaporation of the first ethereal liquids, for commercial ether always contains some water and alcohol, which both dissolve a certain portion of sugar from the root. Unless care, therefore, is taken to extract the impure oil with ether perfectly free from alcohol and water, the oil contained in roots and other vegetable productions, furnishing sugar on analysis, will be estimated too high. Inattention to this point, perhaps, accounts for the great variations which are observable in the determinations made by different persons of the quantities of fat contained in the various articles of food. 8. Determination of the v:hole Amount of Protein Compounds or Flesh-forming Constituents. — As a check upon the direct deter- mination of casein and the indirect determination of insoluble protein compounds, the whole amount of flesh-forming consti- tuents in the carrot and parsnip was ascertained by the indirect method of combustion. About 18 to 20 grains of the dried substance were burned with soda-lime. The amount of nitrogen obtained ac- cording to the method of Will and Varrentrapp, being multi- plied by 6i^, gave the proportion of protein compounds in the roots. 9. Determination of Ammoniacal Salts. — Having found that the juices of many plants contained sometimes considerable quantities of ammoniacal salts, which necessarily must render the determination of the flesh-forming constituents in plants in- Parsnip and White Behjian Carrot, 7 accurate, I was led, therefore, to examine these roots for ammo- niacal salts, and have succeeded in detecting in them small quantities. The plan adopted for finding out the presence of ammoniacal salts in parsnips and carrots and of ascertaining their relative quantities was as follows : — About 1500 grains of the finely grated roots were digested with distilled water, and washed upon a piece of fine linen as long as anything was extracted by water. The clear liquids were immediately precipitated with basic acetate of lead, a re-agent which separates completely all protein compounds. The bulky precipitate thus produced was carefully washed on a filter with distilled water, and the liquid, passed through the filter, after having been slightly acidulated with sulphuric acid, was eva- porated in a porcelain dish to a small bulk. Thus concentrated, it was introduced into a retort, connected with a convenient ap- paratus containing some hydrochloric acid, and destined to absorb the ammonia which is given off during the subsequent distillation of the contents of the retort with soda-lime. It is necessary to choose the receiving apparatus sufficiently large to contain all the liquid in the retort, as the contents of the retort have to be distilled to dryness in order to obtain the last traces of ammonia, which would remain dissolved in the water if no care were taken to evaporate the liquid completely to dryness. The ammonia, which is given off under these circumstances, is fixed by the hydrochloric acid in the receiving apparatus. Its quantity was easily ascertained by evaporating the liquid in the receiver to dryness on a water-bath, with the addition of bichlo- ride of platinum. The precipitate of bichloride of platinum and ammonium thus produced was washed on a weighed filter with a mixture of alcohol and ether, in order to remove the excess of bichloride of platinum, which had been previously added. When quite clean, the filter with the insoluble double salt of chloride of platinum and ammonium was dried at 21^^ F., weighed, and the amount of ammonia which it contained calculated. Having thus given a description of the mode in which the organic analyses were executed, we shall now proceed to state the results obtained in the analyses of both roots. I. Composition of Parsnips, Water. — 1. Dried in the water-bath, the fresh roots lost 81 78 per cent, of water. 2. In another determination 82'32 per cent, were obtained ; or, on an average, parsnips were found to contain 8'2*05 per cent, of water. 8 On the Composition of the Ash. — 1. 275 05 grains of fresh parsnip left, on burning, 2*60 grains of ash : 100 parts of the fresh root, therefore, con- tain *941 per cent, of ash, or 5'16 per cent, in the dried state. 2. 275*7 grains of fresh parsnip left, on burning, 2*55 grains of ash : 100 parts of fresh parsnips consequently gave 0*924 per cent., or 100 parts in the dried state gave 5*23 per cent, of ash. Protein Compounds. — 1. 15'8 grains of substance, dried at 212°, burned with soda-lime, gave 2*88 grains of chloride of platinum and ammonium : or 100 parts of dry parsnips contain 1*14 per cent, of nitrogen, which is equal to 7' 1 2 per cent, of protein compounds. In the natural state parsnips consequently contain 0*20 of nitrogen, or 1*25 per cent, of protein compounds. 2. 12*74 grains of substance, dried at 212°, burned with soda- lime, gave 242 grains of chloride of platinum and ammonium: or 100 parts of dry parsnips contain 1*19 per cent, of nitrogen, equal to 7*43 per cent, of protein compounds. Fresh parsnips, according to this determination, therefore, contain 0-21 of nitrogen, or 1*31 per cent, of protein compounds. According to these determinations, the general composition of fresh parsnips may be represented as follows : — I. Experiment. II. Experiment. Average. Water .... 81-780 82-320 82*050 Inorganic matters (ash) 0-941 0-924 0-932 Nitrogeniscd organic substances, ca- pable of producing flesh . 1-310 1-250 1-280 Substances free from nitrogen, and fitted for support of animal heat and the formation of fat . 15-969 15-506 15-738 100000 100000 100-000 And that of parsnips dried at 212° F. — I. Experiment. II.' Experiment. Average. Nitrogenised substances, capable of producing flesh . . . 7-43 7-12 7-27 Substances not containing nitrogen fitted for support of animal heat and the formation of fat . . 87-41 87 65 87-54 Inorganic matters (ash) . . 5-16 5-23 5- 19 100-00 10000 10000 A glance at these numerical results will show that parsnips contain 6 to 8 per cent, less water than turnips, and 5 to 6 per cent, less than mangolds. The quantity of flesh-forming substances in fresh parsnips is about the same as that contained in turnips. In a dried state, howeyer, turnips are richer in protein com- pounds than parsnips. Parsnip and White Belyian Carrot. D In the following table the results of the detailed proximate analyses of parsnips are contained : — Detailed proximate Composition of Parsnips. In natural State. Calculated dry Water . , . 82-050 Cellular fibre . , 8022 44-691 Ash united with the fibre , •208 i-159 Insoluble protein compounds , •550 3 064 Soluble casein . , •665 3 704 Gum and pectin , •748 4-166 Salts insoluble in alcohol , •455 2-535 Sugar , 2-882 16-055 Salts soluble in alcohol . , •3.S9 1-888 Ammonia, in the state of ammon iacal salts •033 •184 Starch . , , 3-507 19-537 Oil . . . • • •546 3041 100-005 100-025 The ash of parsnips has been analysed by Dr. Richardson, with the following results : — Composition of the Ash of Parsnips. xroiasu Soda 3-11 Magnesia . 9-94 Lime . 11-43 phosphoric acid 18-66 Sulphuric acid 6-50 Silica 410 Phosphate of iron 3-71 Chloride of sodium 5-54 By moistening a transverse section of the root of parsnip with tincture of iodine the external layers are coloured deep violet- blue, whilst the remaining portion of the root is not discoloured. By this means three distinct circles can be distinguished on a transverse section of parsnip : one interior, formed by the heart of the root, an exterior coloured deep violet-blue by the pro- duction of iodide of starch, and an intermediate circle between the heart and the exterior blue coloured zone. This shows dis- tinctly that starch does not exist in the heart, nor in the layers next to it, but that it is all deposited in the external layers of the root. On further examination of these three sections of the root, I have also found that the intermediate layers contain much more protein compounds than either the heart or the outer layers, where the starch is deposited. The intermediate portions between the heart and the outer layers, indeed, contained in this instance 10 On the Composition of the one-half more of flesh-forming constituents than the other por- tions of the roots, as will be seen from the following determina- tions : — Layers between In outer Layers. Heart, the Heart and the outer Layers. Percentage of nitrogen . . 1-039 r067 1-500 equal to Protein compounds . . . 6'493 6*668 9-375 It is worthy of notice, that the albuminous or protein com- pounds are not uniformly distributed throughout the whole mass of the root. I have not examined any other root in this respect ; but, judging from analogy, we may expect to find a similar dis- tribution in other kinds of roots. In ascertaining the nutritive value of roots, which is now usually done by the indirect method of combustion, care must be taken to obtain for analysis a fair average sample of the whole root, for the nutritive value of the root will either be stated too high or too low if the portions analysed contain more of the exterior or the intermediate portions of the root, as actually contained in the whole root. For this reason I find it advisable to prepare the sample of the root to be used for combustion, by cutting the whole root into slices, which, on being dried, are powdered together. A fair average sample of the whole part is thus obtained for analysis, and all errors, arising from the want of uniformity of distribution of the albuminous matters in root- crops, are thereby avoided. II. Composition of the White Belgian Carrot. a. Carrots grown in 1851. Water. — 1. Dried in the water-bath fresh carrots lost 88*06 per cent, of water. 2. In a second determination 88*47 per cent, of water were found. » On an average carrots thus contain 88 26 per cent, of water. Ash. — 1. 100 parts of fresh carrots were found to contain 0*74 per cent, of ash. In the dried state, accordingly, they contain 6*22 per cent, of ash. 2. In a second determination the percentage of ash in fresh car- rots was ascertained to be 0*75, or in dried roots 6*56. On an ave- rage fresh carrots thus contain 0*74 per cent., and in the dried state 6*29 per cent, of ash. Protein Compounds. — 1281 grains of dry carrots burned with soda-lime gave 166 grains of chloride of platinum and ammo- nium. 100 parts of fresh carrots accordingly contained 0*095 of nitrogen equal to 0*596 of protein compounds; and in the dried Parsnip and White Belgian Carrot. 11 state 0*813 of nitrogen, equal to 5*081 of protein compounds. According to these determinations the general composition of fresh carrots grown in 1851 may be represented as follows : — I. Experiment. 11. Experiment. Average. Water . . . .88-060 88*470 88*260 Organic matters containing ni- trogen, capable of producing flesh . . . . *696 -696 '696 Substances not containing ni- trogen, fitted to support respira- tion and for the formation of fat 10*604 10*184 10*399 Inorganic substances (ash) . '740 '750 '745 100*000 100-000 100*000 The dried carrot consequently has the following general com- position : — I. Experiment. II. Experiment. Average. Organic matters containing ni- trogen (flesh-forming principles) 5*081 5*081 5*081 Substances free from nitrogen (lieat and fat producing sub- stances) . . . .88-699 88*359 88-629 Inorganic matters (ash) . . 6*220 6-560 6*290 100-000 100*000 100-000 h. Carrots grown in 1852. Water. — 1. Fresh carrots were found to contain 88*567 per cent, of water. 2. In a second experiment 100 parts of fresh carrots lost 8886 7 per cent, of water. On an average the fresh carrots of 1852 growth contained 88 717 per cent, of water. Ash. — 1. In the first determination the percentage of ash in fresh carrots was found to amount to 0*697 per cent. The dried carrot accordingly contained 6 10 per cent, of ash. 2. In a second determination the percentage of ash in carrots in their natural state amounted to 0*706 per cent. In the dried state, according to this determination, carrots contain 6*26 per cent, of ash. Protein Compounds. — 15*79 grains of carrots, dried at 212*^ F., burned with soda-lime, gave 2 '20 grains of chloride of platinum and ammonium. 100 parts of dried substance thus contain 0875 per cent, of nitrogen, equal to 5*462 of protein compounds. In the natural state, consequently, these carrots contain 0*098 per cent, of nitrogen, or 0-612 of protein compounds. The ge- neral composition of the carrots in their natural state thus was as follows : — 12 On the Composition of the L Experim«»nt. II. Experiment. Average." Water . . . Organic matters containing ni- trogen, and capable of producing flesh .... Organic matters not containing nitrogen, and fitted to support animal heat and for the forma- tion of fat . . . Inorganic substances (ash) 88-567 -612 10-124 •697 88-867 •612 9-815 •706 88-717 •612 9^970 •701 100 000 100^000 100-000 Dried at 212° the general composition of canots, grown in 1852, is as follows : — I. Experiment. II. Experiment. Average. Nitrogenised substances (flesh- forming principles) . . 5*462 5*462 6-462 Substances not containing nitrogen (heat and fat producing matters) 88 • 438 88 • 278 88 • 358 Inorganic substances (ash) . 6^100 6*260 6*180 100-000 100-000 100-000 It will be observed that the composition of the carrots grown in 1851 was almost identical with that of the carrots grown in 1852. In round numbers carrots may, therefore, be assumed to contain about 88 per cent, of water and 12 per cent, of solid matter. Detailed proximate Composition of Carrots. The carrots analysed were found to contain 87-234 per cent, of water in one experiment and 87-434 per cent, in a second. On an average they contained, therefore, 87-338 per cent, of water. In the following table the composition of canots in their natural state, and dried at 212 , is represented: — Table showing the Proximate Composition of Fresh and Dried White Belgian * Carrots. Water ..... Cellular fibre .... Inorganic matters attached to the fibre Sugar ..... Salts soluble in alcohol Gum and pectin Inorganic salts insoluble in alcohol . Soluble casern Insoluble protein compounds Oil . . Nitrogen in the state of ammoniacal salts 99-963 99-707 In Natural State. Dried at 81 2° F. . 87-338 3-471 27-412 •145 1-145 6-544 51 682 •409 3-230 •885 6-989 *293 2*314 -498 3 934 •169 1*334 •203 1-604 -008 •063 Parsnip and White Belgian Carrot, 13 The ash of Belgian carrots has been analysed by Professor Way, who gives the following results as representing the average composition of five analyses of the Belgian carrot : — Silica . 1-19 Phosphoric acid 8-55 Sulphuric acid 6-55 Carbonic acid 17-30 Lime 8-83 Magnesia 3-96 Piroxide of iron 1-10 Potash . 32-44 Soda 13-62 Chloride of sodium 6-50 99-94 A comparison of the composition of these white carrots with that of the parsnips, which has been stated above, suggests to us the following observations : — 1 . There is a general resemblance in the composition of both roots. 2. Parsnips, however, differ in composition from white car- rots chiefly by containing less sugar, the deficiency of which is replaced by starch, not occurring in carrots. 3. White Belgian carrots generally contain 5 to 6 per cent, more water than parsnips. Thus fresh carrots contain on an average but 12 per cent, of solid substances, whilst parsnips contain as much as 18 per cent. In their natural state parsnips, therefore, will be found much more nutritious than carrots. 4. The nutritive value of parsnips, in so far as it is dependent on the proportion of flesh-forming constituents which are found in the root, according to the above results appears to be greater than that of carrots. Whilst fresh parsnips contain 1*30 per cent., and dry 7*25 per cent, of flesh-forming constituents, Belgian carrots were found to contain only 0-612 per cent, of protein com- pounds in their natural state, and 5*46 per cent, in their dried state. Compared with other crops parsnips are about as rich in albuminous compounds as mangolds, and ought, therefore, to go as far as mangolds in producing flesh. 5. Tlie proportion of ammoniacal salts which occurs in the parsnip and in the carrots amounts to mere traces, which do not render inaccurate the determination of the nutritive value of these roots by the indirect method of combustion. Parsnips, richer in protein compounds than carrots, also contain more nitrogen in the form of ammoniacal salts. 6 As' compared with carrots parsnips contain a double pro- 14 Composition of the Parsnip and White Belgian Carrot. portion of fatty matters. They ought, therefore, to be superior as a fattening ;iiaterial in the feeding of stock. 7. The differences in the relative proportions of cellular fibra in both roots are very great. The cellular fibre occurring in carrots, parsnips, turnips, mangolds, &c., must not be regarded as useless in the animal economy^ for there can be little doubt that the soft and young fibres of these roots are readily converted in the stomach of animals into gum and sugar, and applied in the system to feed the respiration, or for the formation of fat. Thus, on the whole, parsnips appear to possess greater value than white Belgian carrots as a feeding or fattening material. Parsnips are indeed very valuable as an article of food ; they are liked by cattle, and highly esteemed by Continental farmers for fattening stock. Moreover, they stand the frost better than any other root-crop, and keep well for a long time, as they contain less water than almost any other root-crop usually cultivated in England. On these grounds I would, therefore, strongly recom- mend the field cultivation of parsnips. LONDON: Printed by William Clowes and Sons, Stamford Street. ON THE COMPARATIVE VALUE OF DIFFERENT ARTIFICIAl MANURES FOR RAISING A CROP OF SWEDES, WITH REMARKS ON THE COMPOSITION OF THE MANURES EMPLOYED IN EXPERIMENTAL TRIALS MADE AT THE ROYAL AGRICULTURAL COLLEGE, CIRENCESTER. By Dr. AUGUSTUS VOELCKER, PROFESSOR OF CHEMISTRY IN THE ROYAL AGRTOULTURAI, COLLEGE, CIRENCESTER. LONDON. M D C C C L V. FROM THE JOURNAL OF THE ROYAL AGRICULTURAL SOCIETY OF ENGLAND, VOL. XVI^ PART I. ARTIFICIAL MANURES FOR SWEDES. It is strange, that whilst an extended experience has proved in the most positive manner the specific action of phosphatic manures, and the decided advantages which result from their application to root crops, the employment of manures either greatly deficient in phosphoric acid, or wanting altogether this important fertilizing agent, should still be recommended by some practical men for raising a crop of swedes, turnips, or any other root crop. No less strange appears the preference which some farmers give even to half-inch bones over superphosphate of lime, although the superior value of the latter fertiliser has been ascertained in numerous practical experiments, and consequently has been recommended by high agricultural authorities, as by far the most economical form in which bones ought to be applied to the land. Still more surprising appears the ready sale which many artificial manures find, although their composition plainly indicates the utter worthlessness of the manufactured article, or the great discrepancy between the price at which it is offered for sale, and its per centage of really valuable fertilising constituents. But strangest of all, it strikes us, is the fact that the sale of down- right trashy manures, or to say the least of them manures of a very inferior description, is often perpetuated for a long time by high flourished testimonials, given by men of character, and possessed of a degree of practical skill whicli entitles them to a considerate hearing. It is further worthy of observation, that valuable artificial manures are often employed even by good farmers in the cultivation of crops on which, as experience has proved, they are used with far less advantage than on others. Thus for instance, in many parts of England, but more especially in Scotland, Peruvian guano is used extensively as a manure for turnips, in preference to superphosphate of lime, not- withstanding the publication of numerous comparative field experiments, which have established the superior value of super- phosphate as a manure for root crops, and which have shown likewise that the greatest fertilising effect of guano is realised by applying it to a white crop or to grass land. Strange as these facts may appear at first sight, yet a little consideration, I think, will point out the reasons on which the objectionable practices to which reference has just been made are founded. Is there not afforded a clear proof in these and similar b2 4 Artificial Manures for Sicedes. practices, that a knowledge of the principles on which the fertilising effects of manuring matters depend is by no means so generally spread amongst the agricultural community as it is desirable it should be ? Do they not show that the specific action even of our standard fertilisers is unknown to many, and that consequently the choice of a manure for a particular crop is more regulated by chance or habit than by a consideration of the peculiar effects on vegetation which characterise many manures ? How often do we not see a manure which has been employed upon wheat with considerable benefit, indiscriminately applied on every description of crops ? Do we not recognise in some of the facts to which allusion lias been made a reluctance of many to change a manure which hitherto has been used with advantage for another, recommended by the best authorities as a superior fertiliser ? and on the other hand a willingness in others to submit to an experimental test that which is not really worth the trouble of trial ? I do not doubt most readers will repl^ to these queries in the affirmative. But, I think, we may recognise still more in the proffered observations. It strikes me, that a trial in the field with different manuring matters is often considered an easy thing, whereas it is in reality a difficult task to perform a good field experiment. The reasons of this are obvious. The neglect of a single point which ought to have been attended to in the execution of an experimental trial in the field, or the com- mission of a fault, which cannot in this instance be so readily remedied as many other mistakes, or uncontrollable circumstances which interfere, but which pass by unnoticed, at once spoil the final result of the experiment, and consequently the inferences deduced from it are erroneous and apt to lead astray. Indeed a review of most published experimental field trials has convinced me, that comparatively speaking few have been undertaken with that amount of caution, candour, care, practical and scientific skill, premeditation, power of observation and general intelli- gence, which is requisite for the performance of a field experiment from the result of which trustworthy practical inferences can be deduced ; and I have no hesitation in saying that the suppression of the majority of our recorded field trials with different manures would be a benefit to the agricultural community, inasmuch as they are calculated to mislead instead of to direct the practical man in his operations on the farm. Then again, often no regard is had to the composition and physical properties of the soil on which experiments are tried ; no notice is taken of the meclianical state of preparaticm in which it is found at the time when the experiment is made ; casualties, such as the partial destruction of the crop by insects, unpropitious weather, &c., are overlooked ; manures differing Artificial Manures for Swedes, 5 widely from each other in composition, and consequently possessing totally different specific actions on vegetable life, are tried against each other ; or powerful fertilisers occasionally are employed in quantities, or in a mode in which they injure instead of benefiting the plants ; and a variety of other mistakes not seldom are committed, and other circumstances of importance overlooked, which all tend to affect the result of the trial. Thus for instance, experiments with different fertilisers occasionally are tried on land which is in so excellent a condition that the best manure hardly makes any impression on the yield of the crop. It is forgotten that the agricultural capabilities of soils cannot be increased ad libitum to any extent, and that consequently the addition of the most valuable fertiliser to land which has almost reached its maximum state of fertility, which it either possesses naturally, or into which it has been brought by long cultivation, will produce no more effect than the most worthless manuring mixture. Land in such a high state of fertility can be compared to the replenished stomach of a well fattened animal ; the one is as little benefited by the best manure, as the other is by the choicest food. On the contrary, the most powerful fertilisers applied under such conditions are exactly those which may and do occasionally even produce undesirable effects on vegetation, just as the richest food is more apt to spoil a satiated stomach than a plainer dish. Hence it is that statements to the effect that such or such a manure has produced as great an effect as the best Peruvian guano, or any other manure of well-known fertilising power, or has even surpassed the best manures in its effects, find their way into the hands of dealers in trashy manures, or to say the best of the manures of a very inferior description. For this reason the printed testimonials which accompany the offer for sale of artificial manures do not always possess that value which many attach to tliem, not even when they are the genuine emanations of well-known and strictly honest agriculturists ; for as I have said already, trustworthy inferences from the results of experi- mental trials can only be drawn, if a vast variety of circumstances are taken into account, the recognition of which requires much experience, and I am almost inclined to believe, a special training for this branch of experimental inquiry. Comparatively speaking few men accustomed to practical pursuits during the greater part of their life, and dependent for the support of their families upon their business, are in a position to execute and direct field ex- periments with sufficient accuracy for the results to confer any permanent benefit on the farming community. It is indeed an unjust accusation which is sometimes made against the practical 6 Artificial Manures for Sioedes. farmer, that he has little inclination for undertaking experimental trials in the field. Another circumstance to which reference has been made as calculated to vitiate tiie results of field experiments, and to jjive rise to erroneous views with regard to tiie value of fertilising materials, is the improper state in which otherwise good manures are occasionally applied to the land. An example or two, which came under my personal observation, will I hope bear me out in making this remark. I have repeatedly heard it asserted by good farmers, who had tried both the ammoniacal liquor of gas-works, and the refuse tar at the same manufactories, that gas-tar produced a much better result on grass and wheat than the ammoniacal liquor, and that consequently the former refuse was worth more in an agricultural point of view. On further inquiry I learned the reason of the small estimation in which this liquid was held by those who preferred to employ the gas-tar as a manure. The ammoniacal liquor, I was told, burns up the grass, whilst gas-tar makes it look more green and succulent. Here we have a striking example in illustration of the entertain- ment of erroneous views, to which an improper application of manures is apt to lead. Ammoniacal liquor of gas-works is far too powerful a manure to admit of its application in an undiluted form, and when used unmixed with water or any other diluting substance, as was here the case, it invariably burns up vegetation almost completely, unless a continued fall of rain provides for the necessary dilution, which has been neglected by the farmer. Ammoniacal liquor owes its chief fertilising value to tlie ammonia, which exists in it almost altogether as a carbonate, and contains nothing detrimental to vegetable life ; but like oxygen, which is so essential for animal life, carbonate of ammonia must be considerably diluted in order that it may produce a beneficial effect. In gas-tar, on the other hand, but little carbonate of ammonia is present ; and for this reason it may be applied to the land undiluted, without fear of burning up the young plants. But it does not follow from this that gas-tar is a more valuable manure than the ammoniacal liquor, for it is easy to prove that gas-tar is only in so far valuable as a manure, as it is mixed with the watery ammoniacal liquor of gas-works. Both these refuse matters are collected together in one tank, and some of the watery ammoniacal liquor therefore remains always mixed with the tar. In the tar itself there are present no sub- stances which contain either nitrogen, phosphoric acid, or potash, nor indeed any constituent which has the slightest fertilising value ; for the organic, resinous, and oily compounds occurring in gas-tar are all compounds of carbon and hydrogen, or carbon, hydrogen, and oxygen, and as such they will furnish, on ultimate Artificial Manures for Swedes. 7 decomposition, carbonic acid and water only. But as all cultivated soils contain vegetable remains, which afford a much more ready and liberal source for carbonic acid, and as, moreover, by far the greater proportion of the carbon in plants is derived from the carbonic acid existing in the atmosphere, it is needless to make special provisions for the supply of carbonic acid. I have admitted for brevity's sake that tarry matters are readily decomposed, which, however, is by no means the case, for every one knows that tar is extensively employed for preserving timber from decay. As far as tar itself is concerned, I am therefore inclined to ascribe to it an injurious effect as a fertiliser, for it must retard the decomposition of organic remains in the soil or in the compost heap to which it is added, and must thus delay the necessary preparation to which most organic refuse matters must be submitted before they can be assimilated by the growing plants. If notwithstanding gas-tar produces a good effect, it is only on account of the ammonia contained in ammoniacal liquor with which it is mechanically mixed. There cannot remain, however, a shadow of a doubt, that the ammoniacal liquor is a far more powerful and at the same time economical manure, which will produce no injurious effects, and just as beneficial effects as gas-tar, when properly diluted with water. And as ammoniacal liquor is cheaper than gas-tar, and as a fertiliser goes at least ten times as far as the tar, the utility of knowing on what principle the fertilising effects of both refuse manures depend will become at once apparent. Again, shoddy, a wool-refuse of flock-works, is recommended by some as an excellent manure for wheat and corn crops in general, whilst others condemn it as quite useless. How can these differences of opinion be reconciled, when equally good men have ascertained practically the value of shoddy, and know by experience what it is worth as a manure ? I have seen shoddy applied to wheat apparently without the slightest effect, and in other cases the effect produced by the same refuse on wheat was wonderful. A reference to the analysis of shoddy, and a con- sideration of the physical condition of the soils to which and the time at which it is applied, readily explain this contrariety of opinion. Shoddy often contains 20 to 25 per cent, of oil, which, by excluding air and moisture from the interior of the wool-hairs which compose this refuse, prevents its decomposition as effec- tually as the oil in the sardines a I'huile protects the fishes, or a cover of grease the potted meat. At all events, the oil in shoddy retards its decomposition for a very long time ; and as it natu- rally contains hardly any constituent which is of much value as a fertilizer, no effect is produced if shoddy is applied to the land when the young blade of wheat has already made its appearance, 8 Artificial Manures for Swedes. or even if it is applied two to three months before that period. But if the same refuse is added to the land long before the sowing of the crop which it is intended to benefit, or if by some means or the other it is brought into a state in which it will readily ferment, in which case it may be applied at once to the young wheat, a very marked effect will be observed to follow the application of shoddy to corn crops. For under these circum- stances shoddy, which contains from 3 to 5 per cent, of nitrogen, gradually will give rise to the formation of ammonia, which it is well known benefits cereals in an especial manner. In light and porous soils this necessary preparation proceeds much more rapidly than in stiff heavy soils, and consequently the condition of the land will likewise modify the action of this refuse manure. Under the most favourable circumstances, however, shoddy ought to be used in an unprepared state, for the interval between the ingathering of a green crop and the preparation of the land for the corn crop is generally too short to allow the wool refuse to enter into decomposition ; its effects consequently are lost upon the crop which it is intended to benefit, and unless a second com crop is grown, shoddy will but little benefit the second crop in the rotation, for it is a refuse which owes its fertilising effect almost altogether to the nitrogen it contains, and which furnishes on decomposition ammonia, and as ammonia does not exhibit the same powerful effect on other crops which it does on the cereals, the chief advantages which may be derived from the application of shoddy are lost. These examples, I hope, will be sufficient to prove the cor- rectness of the remarks which have been made. They are remarks founded on actual facts which have come under my per- sonal notice. I might easily point out other cases, with which I have become personally acquainted, as bearing on this subject, but this will perhaps be superfluous, and I will therefore merely observe, in addition to the remarks already made, that when all care, at- tention, and labour have been applied, uncontrollable circum- stances often interfere which spoil the experiments in the field. It affords me, therefore, much pleasure to have the privilege of giving an account of some experimental trials which were made last season, under peculiarly favourable circumstances, on the farm attached to the Royal Agricultural College. These experiments were made on Swedish turnips, with the following fertilisers : — 1. Guano. 2. Mixture of guano and dissolved coprohtes. 3. Bone-dust. 4. -Home-made superphosphate of lime. Artificial Manures for Swedes. 9 5. Economical manure. 6. Nut-refuse. 7. Dissolved coprolites. 8. Commercial dried night-soil. 9. A mixture of sand, guano, dissolved coprolites, and superphosphate of bones. The field selected for the experimental trials with these ma- nures was almost perfectly level, and throughout of a unifoim depth. It had been cropped alike in every paft in previous years, and otherwise uniformly cultivated. The surface soil is shallow, and rests on the great oolite limestone, from which it is separated by a clayey subsoil of small dimensions. Alto- gether it is a turnip soil of but moderate quality, belonging to the class of calcareous soils, as will be seen by glancing at the subjoined analyses. 1. Mechanical Examination of Soil of Experimental Field, Cirencester. a. On passing 24 lbs. of the surface soil through a ^ inch sieve, there were separated : Large stones, weighing 1 lb. 6 ounces. Soil, passing through the sieve . . . 22 ,, 10 „ 24 lbs. h. Of the soil passing through the ^ inch sieve, 1 lb. was riddled through a series of 4 perforated zinc cullenders, fitting into each other. The uppermost cullender was provided with apertures, measuring \ of an inch in diameter ; the second with apertures \ of an inch in diameter ; the third was perforated with holes tV in. diameter ; and the fourth with boles -3V in. diameter. By this means it was divided into five different portions, the relative proportion of which was as follows : — No. 1. On i inch sieve w^erc left 121 grains, fragments of limestones. 2. ,, I „ „ 643 grains of soil, including a large proportion of limestones. 3. „ ^ „ „ 2,246 grains. 4. „ 35 ,, ,,^ 1,192 ,, 5. Through the last sieve passed 2,882 „ 7,085 „ A mechanical examination of this description is useful, inas- much as it enables us to form some idea of the state of division in which the soil-constituents actually occur, and in experimental trials enables the reader to judge for himself whether or not the soil was sufficiently pulverised for the crop experimented upon. It will be observed by these data that the mechanical preparation of the experimental field has been carefully attended to. B 3 10 Artificial Manures for Swedes. c. TliC portion collected on the first sieve consisted entirely of fragments of limestones, and that of No. 2 nearly altogether of similar but smaller fragments. Both were rejected in preparing a fair average sample for chemical analysis, and the portions from Nos. 3, 4, were powdered in a mortar, passed through the -3*2 inch sieve, and mixed with No. 5. Before submitting it to chemical analysis, the average sample was separated by washing into the following portions: 100 parts of average soil contained — Organic matter and water of combination .... 6 ' 339 Burned deposit after standing 5 minutes .... 69*600 10 „ .... 3-880 15 „ .... 3 230 Remaining in suspension after standing longer than 15 minutes 16 "951 100-000 The first deposit consisted of a calcareous sand, whilst the second and third were coarse clay, and wliat remained in sus- pension fine clay. The general composition of the soil can therefore be expressed as follows : — Organic matter and water of combination 6 ' 339 Clay 24*061 Calcareous sand 69 * 600 100-000 2. Chemical Examination. On analysis of the average sample prepared as described above, the following results were obtained : — 100 parts contained — Organic matter and water of combination .... 6*339 Oxides of iron and alumina, with a trace of phosphoric) q.oii acid . } Carbonate of lime 64*566 Magnesia trace Sulphuric acid ditto Chlorine ditto Potash and soda 1*032 Insoluble siliceous matter 28 • 947 100*195 It will be observed that carbonate of lime greatly preponderates in this soil, and that the proportion of alkalies is but small, whilst mere traces of phosphoric and sulphuric acid were found in it. Calcareous soils of such a composition are generally un- productive. The experimental field was carefully measured out, and divided Artificial Manures for Swedes. 11 into ten different plots of one-eighth of an acre each. These experimental plots were arranged side by side in continuous rows of drills, care being taken to reject the headlands from the experi- mental plots. The space of one-eighth of an acre was occupied by three rows of drills. The different manures were all applied to the land on the same day ; and in order to secure their full efficacy and their even distribution, they were put on the ridges by hand in a groove, made by a hoe being drawn along the top ; the different manures were then covered with some soil, and after passing a roller over the drill, all the swedes were sown by ridge- drill on the 20th of June. Subsequently, all experimental plots were treated in precisely the same way, and care was taken to render the experiments in every respect strictly comparative. One of the experimental plots was left unmanured ; the nine remaining were manured in the manner described, with the sub- joined quantities of the manures, which have been mentioned already. These quantities of the different fertilisers were obtained in each case witli an expenditure of 5*., or each experimental plot was manured at the rate of 2Z. per acre. Thus to Cost, 5s. for each Plot. Plot I. was applied . 56 lbs. of guano. 84 lbs. of coprolites, dissolved in sulphuric acid, and 28 lbs. of guano. 100 lbs. of bone-dust. 93 lbs. of home-made superphosphate. 56 lbs. of economical manure. 120 lbs. of nut-refuse. 140 lbs. of dissolved coprolites^ Nothing-. 180 lbs. of commercial dried night-soil. A mixture of 1 bushel soot, 30 lbs. of guano, with dissolved coprolites, and super- phosphate of bones. Before stating the yield of each experimental plot, I may be permitted to offer some observations on the condition of the growing crops, and on the chemical composition of the different fertilisers used in these experiments. All have been analysed in my laboratory, either completely, or when a complete analysis appeared superfluous, only those substances were determined on which principally the efficacy of the manure depended. Plot I. Manured with 56 lbs. of guano, or at the rate of 4 cwts. per acre. Cost of manure 5s., or 2/. per acre. The young plants came up remarkably well, and looked for a considerable time as well, if not better than the rest of the experimental plots. When, howcvei, the bulbs began to swell, it was evident to the eye that tliQ guano turnips would be left B 4 I. was applied II. >» n III. IV. V. VI. VII. /III. IX. X. 12 Artificial Manures for Swedes. behind by the superphosphate, and probably also by the dis- solved coprolites, mixed with guano ; and the result has proved that this was actually the case. The guano was best Peruvian, and was bought at the price of 10/. per ton. On analysis its composition was ascertained to be as follows : — Water 12'420 Organic matter and ammoniacal salts 62 • 980 Phosphates of lime and magnesia (bone-earth) 25 '066 Alkaline salts, chiefly chloride of potassium and sodium, with a small quantity of alkaline phosphates and sul- phates 8-262 Insoluble siliceous matter 1*607 100-234 Containing nitrogen 14*177 equal to Ammonia 17*215 The guano employed in the experimental trial, as shown by its analysis, was genuine Peruvian guano of good qualities. Inferior kinds of guano, such as Saldanha-bay and Patagonian, 1 think, would have given a better result, for they are richer in phosphates than Peruvian ; and as the commercial value of guano is principally regulated by the proportion of ammonia it contains or furnishes on decomposition, and as ammonia does not benefit root crops in an equal degree as white crops, whereas phosphatic manures exercise a specific action on roots, which causes them to swell and thus to increase the crop, it would appear that, to the extent to which Peruvian guano is richer in nitrogenized matters than other kinds of guano, it becomes less valuable. Indeed, it appears to me a great waste to apply Peruvian guano alone to swedes or turnips ; and I hope to sup- port this opinion by the practical proofs which will presently be mentioned. Plot II. Manured with 84 lbs. of coprolites dissolved in sulphuric acid and 28 lbs. of guano, or at the rate of G cwts. dissolved copro- lites and 2 cwts. of guano. Cost of manure 5«., or 2/. per acre. At first no difference in the appearance of the swedes, when compared witli those grown with guano alone, could be observed ; but at a more advanced season the roots looked decidedly better than those of Plot I., and, indeed, of most other experimental plots. The dissolved coprolites were made on the farm by digesting the finely ground, so-called Suffolk coprolites, with one-third their weight of sulphuric acid, and allowing this mixture to become nearly air-dry by keeping. It was then mixed with guano, and thereby obtained in a perfectly powdered and air- dry state. Artificial Manures for Swedes. 13 On analysis the ground coprolites were found to contain in 100 parts — Hygroscopic water 1*20 Water of combination, and a trace or organic matter 3*20 Oxides of iron and alumina ... 4*84 Lime , 39*81 Magnesia 5*68 Phosphoric acid 23*48 equal to 47 "82 of bone earth. Carbonic acid 5*82 Insoluble siliceous matter . . . 12*56 Alkalies, sulphuric acid, and loss . 3*41 100*00 The price of the dissolved coprolites made on the premises was 4/. per ton. At the present prices of the raw coprolites, tlie dissolved article would be more expensive. Plot III. Manured with 100 lbs. of bone-dust, or 7 cwts. and 16 lbs. per acre. Cost of manure 5s., or 21. per acre. The swedes on this plot looked healthy, but, it struck me, rather unequal. A distinct difference in the average size of the roots, as compared with the two preceding plots, soon bee ame apparent to the eye when the root began to swell. On analysis the bone-dust was found to contain in 100 parts — Moisture 18*12 Organic matters (gelatine and fat) 29 ' 29 Phosphates of lime and magnesia (bone-earth) 44*22 Carbonate of lime 5*49 Alkaline salts (chiefly common salt) 1 '49 Sand 1*39 100-00 Containing nitrogen . 4*28 equal to Ammonia 5.23 Previous to crushing they had undergone no preparation what- ever, and contained consequently a great deal of fat, which cir- cumstance explains their slow action. 25, more per quarter was paid for obtaining the bone-dust in a finer state than it is usually sold. A bushel on an average weighed 44 lbs., and the price per ton was 5/. 12^. Plot IV. Manured with 93 lbs. of home-made superphosphate of lime, or at the rate of 6 cwts. and 72 lbs. per acre. Cost of manure 5s., or 2Z. per acre. The seed came up well, but at the first stage of growth the swedes sowed with guano appeared somewhat better. At a later period the difference in the appearance of these two plots less striking; and when the bulbs began to swell, it was 14 Artificial Manures for Swedes. evident that in all probability superpliosphatc of lime would surpass the other manures in its effects upon Swedes. Experi- ence has proved it to have been the case. In the preparation of the superphosphate the fine bone-dust, of which an analysis has been given already, was first moistened with one-third its weight of boiling water, and after the water had been thoroughly soaked in by tlie dust, one-third of its weight of brown oil of vitriol was added. The mixture was made in a wooden trough, from which it was removed and placed in a heap, after it had become sufficiently consolidated. It was made a considerable time before the sowing of the turnips, and had thus time to become thoroughly disintegrated in the heap and dry on keeping. Before its application to the land, it was broken down with a wooden mallet into a fine powder. Boiling water was found to assist the dissolving action of the oil of vitriol in a very high degree : it can therefore be recom- mended as greatly preferable to cold water. The cost of the dry home-made superphosphate was 6/. per ton. Plot V. Manured with 56 lbs. of economical manure, or at the rate of 4 cwts. per acre. Cost of manure 5s., or 21. per acre. In a very short time after the bulbs had begun to swell, this plot was left behind by all the other experimental plots, the undressed portion excepted. The difference in the appearances between this plot and the other manured plots became more and more striking as the crops approached maturity, when the most unexperienced eye could observe that the economical manure had done little good to the swedes. It was, indeed, impossible to observe the slightest difference between the unmanured plot and the one dressed with economical manure. This unfavour- able result cannot surprise any one who knows that phosphoric acid applied in a form in which it can be readily assimilated by the growing plant, more than other fertilizing constituent, benefits root crops, if he throws a glance at the following analysis : — Composition of Economical Manure. Water 36.525 Protosulphate of iron (green vitriol) 23*756 Sulphate of lime •860 Sulphate of magnesia *204 Bisulphate of potash 4.677 Bisulphate of soda 10928 Sulphate of soda (Glauber salt) 15-143 Sulphate of ammonia 2*648 Insoluble siliceous matter (sand) 5*850 100*591 Containing ammonia • 683 Artificial Manures for Swedes. 15 This manure, it will be observed, consists principally of crystallized green vitriol and bi-sulphate and sulphate of soda. These sulphates of soda are obtained at a cheap rate, as a refuse in several chemical manufactories. Both the crystals of green vitriol and Glauber salt or sulphate of soda contain much water of crystallization ; hence the large amount of water (36 J^ per cent.) in a tolerably dry substance. The economical manure has a strongly acid taste and reaction, and might therefore be sup- posed to contain a great quantity of soluble or acid phosphate of lime ; but whilst it contains only about 7-lOths per cent, of ammonia, phosphoric acid is excluded entirely from its com- position. We need not, therefore, feel astonished that it pro- duced scarcely any effect upon swedes. The price at which the economical manure sold last season, and is again sold this season, is 12/. per ton. Its constituents can be furnished at about 3/. a ton ; the manufacture of a manure of the above composition thus might even pay well if sold at 5Z. per ton instead of 12/. per ton, its actual price. Plot VI. Manured with 120 lbs. of nut refuse, or at the rate of 8 cwts. 64 lbs. per acre. Cost of manure 5s., or at the rate of 2Z. per acre. The swedes upon this plot had as healthy an appearance as any of the experimental plots, and it was difficult to observe any difference in the relative average size of the bulbs of this plot and those of the next and the tenth plot. This refuse was the powdered cake of an oily nut, probably cocoa-nut. It was submitted in my laboratory by my pupil, Mr. Louch, to a partial analysis, who found in 100 parts — Water 11-60 Organic matters 79*12 Inorganic matters (ash) 9*28 100-00 This quantity of organic matter on combustion gave in two experiments — 1 Exp. 2 E^p. Average. Nitrogen 4«826 4'90 4'863 In the 9*28 of ash were found — Earthy phosphates 4*12 Phosphoric acid, combined with alkalies 'IS Sand and soluble silica 2*42 Alkalies, magnesia, &c 2-61 9-28 grs. It will be observed that this nut-cake manure contains a very large amount of nitrogen, and also a quantity of phosphates and alkalies which is by no means inconsiderable. It. was sold in 16 Artificial Manures for Stoedes. small quantities at the rate of 5/. per ton ; but I am told in \ar^e quantities it may be had at 31. a ton. At the latter price it certainly is very cheap and well worthy the attention of the farmer, as it is a powerful manure, which, however, is more economically applied to wheat or grass-land than to turnips. Plot VIII. Unmanured plot. As mentioned already, a very great difference was soon per- ceptible between this and most manured experimental plots (except the economical plot). The swedes were very small, but otherwise in good condition. Plot IX. Manured with 180 lbs. of commerdal dned night-soil, or at tho rate of 12 cwts. and 96 IT3S. per acre. Cost of manure 5s., or 21. per acre. No difference in the probable yield of this plot and the next could be observed. Plots IX. and X., however, did not pro- mise so good a crop as Plots I., II., VII., and especially IV. The effect produced by the dried night-soil was not so great as might have been expected. Pure night-soil is a powerful manure, which contains a considerable proportion of phosphoric acid, and for this reason ought to benefit root-crops in a decisive manner. It must be borne in mind, however, that the dried night soil was a commercial article, which, like many commercial articles, possessed a better name than it was entitled to by its composition. For the preparation of this manure a good deal of water was retained, and no doubt a large proportion of rubbish besides common salt was employed, as will be seen by glancing at the subjoined analysis : — Composition of Commercial dried Night- Soil Manure. Water 19-712 Organic matters 17*484 Carbonate of lime 9*229 Magnesia '168 Oxides of iron and alumina 20 '061 Phosphoric acid 4*399 Common salt with some sulphate of soda and potash . 11- 864 Insoluble siliceous matter (sand and brick-dust) . . 16*941 99-858 It was sold at 3/. 25. per ton. Plot X. Manured with a mixture of 1 bushel of soot, 30 lbs. of guano and dissolved coprolites, and bone superphosphate to make up the 5s. expenditure. Cost 5s., or 2/. per acre. Guano, dissolved coprolites, and bone-superphosphate, arc of the same description as the materials used for the other experiments. Per i of an Acre. Per Acre. tons. cwts. lbs. tons. cwts. lbs. 1 9 7 11 12 56 1 12 2 12 16 16 1 2 8 16 1 14 2 13 12 16 15 2 6 16 1 5 10 1 9 11 12 13 5 4 1 3 9 4 Artificial Manures for Swedes. 17 The soot on analysis was found to contain 3 * 833 per cent, of ammonia : it was procured at the rate of %d. per bushel. It having been found on previous trials that it was quite impossible to calculate the yield of each plot by weighing only a small number of roots, the whole produce of each experimental plot was weighed on a weigh-bridge. The following table exhibits the yield of each experimental plot and the weight of the trimmed roots calculated per acre : — Table showing the Produce of trimmed Swedes of Experimental Plots of one-eighth of an Acre, and Weight of Crop per Acre. Plot I. (Guano) yielded „ II. (Guano and dissolved coprolites) yielded „ III. (Bone-dust) ... „ ,, IV. (Bone superphosphate) ,, „ V. (Economical manure) „ ,, VI. (Nut-refuse) ... „ ., VII. (Dissolved coprolites) ,, „ VIII. (Nothing) ... „ ,, IX. (Commercial dried night-soil) „ X. (Mixture of soot, guano, dis- solved coprolites, and bone- superphosphate) . ,, 15 1 10 8 The results obtained in these experimental trials are both interesting in a practical and scientific point of view, and I may therefore be allowed to offer a few remarks which are suggested by them. Before doing this, however, a point of some moment demands special notice. It will be observed that the unmanured portion of the experimental field only gave a produce of 5 tons 4 cwts. per acre. The natural inference which may perhaps be drawn from so small a crop is, that the land was not in a proper state of preparation for the tumip-crop, and that, consequently, all the experiments are not to be depended upon ; I have shown, however, by the mechanical analysis of the soil on which the experiments were tried, that it was well pulverized, and have been assured moreover by our farm-manager, that the experi- mental field was in a fit state of preparation for the swedes. The soil, it is true, was naturally poor, shallow, and rested on lime-stone rock, from which it was separated by a clayey subsoil of inconsiderable depth. But far from considering this circum- stance as being calculated to vitiate the results of the trials, there is much reason to believe that a soil of such a description is peculiarly well adapted for the making of experiments from which legitimate and trustworthy inferences may be derived. A poor soil, it strikes me, is much better adapted to bring out the full manurial effect of different fertilizers than land in the 18 Artificial Manures for Swedes, highest state of fertility. For the productive powers of soils, let it be remembered, cannot be increased to an unlimited extent ; when, therefore, a soil is naturally as productive as it can be under any circumstances, or when by good cultivation it has reached its maximum state of fertility, the addition of the most valuable manure, it is evident, cannot produce any perceptible effect. Under these conditions the best fertilizer would produce no greater effect than an utterly worthless and inexpensive manure Now the closer a soil approaches this condition the less it is adapted for the performance of experiments with manures, and vice versa ; land not very productive, or naturally poor, is just in a condition in which the full effects of different fertilizers can be best discerned, and I am inclined therefore to consider the fact of the experiments having been tried on a naturally poor soil as peculiarly fortunate. A reference to the tabulated statement which has just been given will exhibit very considerable differences in the weight of the bulbs raised by an equal money-value of different manures. Thus whilst 21. worth of home-made superphosphate of lime gave an increase of 8 tons 8 cwts. 16 lbs. per acre, 21. worth of economical manure produced merely 16 cwts. 16 lbs. more per acre than the unmanured portion of the field. Again, it will be observed, that whilst 21. worth of dried night-soil gave only 9 tons 4 cwts. of roots, a mixture of guano and dissolved coprolites gave 12 tons 16 cwts. 16 lbs., and dissolved coprolites alone 11 tons 12 cwts. These differences are still more strikingly exhibited in the following table, in which the different plots are arranged accord- ing to the increase which the various fertilizers employed upon each produced : the table likewise shows the cost at which 1 ton of increase was produced in each experimental trial. Table showing Increase per Acre, and Cost of 1 Ton of Increase, in 10 experimental trials upon Swedes. Coat of 1 ton of Increase per acre. increase, tons. cwts. lbs. £ s. d. No. 1. Home-made superphosphate . . 8 8 16 4 9 2. Dissolved coprolites and guano . 7 12 16 5 3^ 3. Guano 6 8 56 6 2i 4. Dissolved coprolites 6 8 6 3 5. Mixture of guano, soot, dissolved coprolites, and bone super- phosphate 4 16 8 8 3^ 6. Nut-refuse 4 16 084 7. Commercial night-soil 4 0100 8. Bone-dust 3 12 11 1| 9. Economical manure 16 16 29 6J 10. Nothing. (Natural produce 5 tons 4 cwts.) Artificial Manures for Swedes. 19 We thus see that well-made superphosphate was by far the most economical manure in these experimental trials, and the " economical manure " tlie worst of all ; for whilst 1 ton of increase raised with the agency of superphosphate of lime was obtained with an expenditure of 4^. 9rf., 1 ton of increase raised with ** economical manure " would cost no less than 2Z. 9s. 6|rf. for the manure. It is worthy of observation that the land in the preceding year was not manured with farm-yard manure, nor indeed with any manure whatever, and we thus see that with superphosphate alone a better crop of swedes may be raised than with guano. It will be seen that guano produced nearly 2 tons less of swedes per acre than home-made superphosphate, a difference which, considering the small crop furnished by the unmanured land, is considerable, Peruvian guano alone, indeed, should not, as is so often the case, be em])loyed for root-crops, for when employed in small quantities the per-centage of phosphates contained in it is not adequate to enlarge the roots sufficiently, and when used in large quantities it is apt to produce an excess of leaves, which is generally the case with all manures containing like guano a large amount of nitrogenized constituents. Had the experiments been tried on wheat instead of swedes, there can be little doubt but that the results would have been different, and guano, in all probability, would have carried off the palm, for it is on the cereals and upon grass-land that highly nitrogenized manures like guano, soot, blood, &c., produce the most beneficial effects. Next to superphosphate made from bones, the mixture of dis- solved coprolites and guano gave the greatest increase, the crop weighing 12 tons 16 cwts. 16 lbs. per acre; whilst dissolved coprolites employed alone furnished 1 1 tons 1 2 cwts. per acre. This is an exceedingly interesting result, for it shows that a purely mineral phosphatic manure, even when applied in a form in which it can readily be assimilated by plants, does not pro- duce, at least on a poor soil, so large a crop as a mixture in which a portion of the mineral phosphate is replaced by a manure, which, like guano, is rich in nitrogenized constituents. A small amount of an ammoniacal manure, or a fertilizer rich in organic matters, readily furnishing ammonia on decomposition, appears to be sufficient to secure the assimilation of the mineral phos- phate ; for it will be observed, by glancing at the experiment in which a mixture of soot, guano, superphosphate, and dissolved coprolites was used, that if the amount of organic fertilizing matters in a mixture is increased at the expense of its phosphatic constituents, the produce will be reduced. Thus this mixture, in which a portion of superphosphate was replaced by soot and guano, both containing much ammonia, or furnishing it on decom- 20 Artificial Manures for Swedes. position, only gave 10 tons 8 lbs., whilst the produce of the dis- solved coprolites amounted to 1 1 tons 12 cwts. Dissolved coprolites, which follow guano in the above list, virtually produced as great a crop as guano, for the difference of 56 lbs. is not worthy of consideration. Whenever coprolites therefore can be had at a cheap rate, they may be employed as a substitute for bone-dust, provided care is taken to dissolve them properly in sulphuric acid and to mix them with some nitro- genizcd organic manure. The nut-refuse gave as nearly as possible the same produce as the mixture in experimental plot No. X., and commercial night-soil follows next in the list. A comparistm of the crop yielded by bone-dust with that yielded by bone-dust dis- solved in sulphuric acid, will forcibly exhibit the advantages of applying bones in the latter form ; for whilst an equal money value of bone-dust only gave an increase of 3 tons 12 cwts., dis- solved bone-dust gave an increase of 8 tons 8 cwts. 16 lbs. ; or whilst 1 ton of increase raised with the agency of superphos- phate only cost 4^. 9^., 1 ton of increase raised with bone-dust implied an expenditure of 11a. l^d. The form in which an artificial manure is applied to the land thus greatly influences its action. On the whole, we may learn from these experiments that the value of different artificial manures for a crop of swedes, and no doubt also for other root-crops, principally depends cm the amount of phosphoric acid contained in them in a form in which it can be readily assimilated by the plants. In bone-dust there is much phosphoric acid ; but when it is used in an unprepared state, in which it still contains all the fat naturally present in fresh bones, it often remains in the soil for a very long time without readily undergoing decomposition, or that preparation so necessary to bring out its full fertilizing effect. All the experi- ments confirm the general conclusion which has just been expressed ; but more especially the experiment with the economic manure, in which the absence of phosphoric acid was proved by analysis, shows the necessity of applying to root-crops a fertilizer containing a good deal of phosphoric acid. Whatever else the virtues of the economical manure may be, it certainly proved the least economical dressing of all, as it produced only 6 tons 16 lbs. of swedes per acre, or only 16 cwts 16 lbs. more than the unmanured portion of the experimental field. In conclusion I will observe that I have carefully determined the chemical composition of the roots of each experimental plot, in so far at least as it appeared desirable in order to form some idea as to the nutritive value of tlie swedes raised with different manuring matters. Artificial Manures for Stvedes. 21 The results of these examinations .are embodied in the follow- ing table : — Table showing the Proportion of Water in Swedes grown with different Manures. Average Weight of Roots. Per centage amoimt of Plot I. Guano. of water. water. a. Large sized root, weighing 2 lbs. 1 1 ounces . . 88*717 | b. Average sized root, weighing 1 lb, 8 ounces . 87*450 > 87*667 c. Small sized root, weighing 11 ounces .... 86*834 ) Plot II. Dissolved coprolites and guano. a. Large sized root, weighing If lb 88*420 j 6. Medium sized root, weighing 15 ounces . . . 88*600 [ 88*484 c. Ditto root, weighing 15 ounces 88*434 ) Plot III. Bone-dust. a. Large root, weighing 2 lbs. 2 ounces .... 88*034 | 6. Medium size, weighing 1 lb. 13 ounces . . . 89*967 [ 88-467 c. Small root, weighing f lb 87-400 ) Plot IV. Superphosphate of lime. a. Large root, weighing 2^ lbs 88*350 j b. Average sized root, weighing 1 lb. 10 ounces . 89'284 > 88*556 c. Small root, weighing 10^ ounces ...... 88*034 I Plot V, Economical manure. a. Large root, weighing 2 lbs. 2 ounces .... 87*717 | b. Average size, weighing 14 ounces ..... 88*067 / 87*661 c. Small root, weighing 8 ounces 87 200 j Plot VI. Nut-refuse. a. Large sized root, weighing 2f lbs 87*900 j b. Average size, weighing 1 lb. 1 ounce ... 88*384 \ 88*306 c. Small root, weighing 9 ounces 88 * 634 ) Plot Vn. Dissolved coprolites. a. Large root, weighing 2^ lbs 89*417 i ft. Medium size, weighing 1 lb. IH ounces . . . 88-117 > 88*578 c. Small root, weighing 9^ ounces 88*200 ) Plot VIII. Nothing. a. Large root, weighing 1 lb. 11 ounces .... 88-800 j ft. Average sized root, weighing 12 ounces . . . 87*460 > 87 803 c. Small root, weighing 5 ounces 87*150 j Plot IX- Night-soil manure. a. Large root, weighing 1 lb. 10 ounces .... 88*917 \ ft. Ditto, weighing 1 lb. 10 ounces 88*767 [ 88*506 c. Small root, weighing ^ lb 87 ■ 834 ) Plot X. Mixture of soot, guano, dissolved coprolites, and superphosphate. a Large sized root, weighing 2 lbs. 5 ounces . 88*841 | ft. Medium sized root, weighing 1 lb. 14 ounces . 87*131 / 87*376 c. Small root, weighing I lb. . . 86*156 I It will be observed that the proportion of water and solid matter is pretty nearly the same in all the roots of the different experimental plots. The differences in the amount of water in roots of different size also are very trifling : generally, but not always, the larger roots were somewhat richer in water. In the following table the proportion of ash and nitrogen in swedes in natural and dry state is given : — 22 Table Artificial Manures for Stiedes. the Amount of Ash and Nitrogen in Swedes of Experimental Plots. Ash. Nitrogen. In Natural State. In Dry State. In Natural State. In Dry State. Plot No. 1 Ist deter. 2nd deter. 3rd deter. . -561 . -552 . -641 4-98 4»40 4-87 Mean. •298 1st deter. . 2nd deter. . Mean 2^372 2^457 2-414 Plot No. 2 1st deter. 2nd deter. 3rd deter. . '540 . -.548 . -512 4-67 4-81 4'43 •278 1st deter. 2nd deter. . Mean . . 2^434 2-401 2-417 Plot No. 3 Ist deter. 2nd deter. 3rd deter. . -568 . -639 . -655 5-20 6-37 4-75 •274 1st deter. . 2nd deter. . Mean . . 2-402 2 •355 2^378 Plot No. 4 1st deter. 2nd deter. 3rd deter. . -498 . '.516 . -589 4-28 4*82 4-93 •255 1st deter. . 2nd deter. . Mean . . 2^286 2*181 2*233 Plot No. 5 1st deter. 2nd deter. 3rd deter. . -596 . -582 . -558 4-86 4-96 4-36 •300 1st deter. . 2nd deter. . Mean . . 2*43.5 Plot No. 6 1st deter. 2nd deter. 3rd deter. . -5.34 . -581 . -576 4-42 5-01 5'07 •277 1st deter. . 2nd deter. . Mean . . 2*401 2^348 2^374 Plot No. 7 1st deter. 2nd deter. 3rd deter. . -484 . -628 . '554 4-58 5-29 4-70 •263 Ist deter. . 2nd deter. . Mean . . 2-143 2-459 2 •SOI Plot No. 8 1st deter. 2nd deter. 3rd deter. . -561 . -559 . -627 5-01 4-46 4-88 •338 1st deter. . 2nd deter. . Mean 2^748 2-793 2^770 Plot No. 9 1st deter. 2nd deter. 3rd deter. . -538 . -540 . -498 4*86 4-72 4-10 •283 1st deter. . 2nd deter. . Mean 2^379 2^545 2*462 Plot No. 10 1st deter. 2nd deter. 3rd deter. . -562 . -532 . •6.'>4 5-04 412 4-73 •321 1st deter. . 2nd deter. . Mean . . 2-505 2*592 2-548 I do not think the variations indicated by these determinations are sufficiently great to entitle us to say that the swedes of one plot were more nutritious than those of another. On the whole these analyses show that the different fertilizers employed in the experimental trials did not affect the composi- tion of the swedes in any material degree ; consequently tlie question as to the comparative economy of using superphosphate of lime in preference to all the other manures employed in the experimental trials remains simple, and the general conclusions to which these experiments have led are not affected by any differences in the nutritive value of the roots. LONDON : Printed by W. Ci-owes and Sows, Stamford Street, and Charing Cross. ON THE AGRICULTURAL AND COMMERCUL VALUE OF SOME ARTIFICIAL MANURES, AND ON THEIR ADULTERATION. BT DK. AUGUSTUS VOELCKER, PROFESSOB OF CHEMISTRY IN THE ROYAL AGRICULTURAL COLLEGE, CIRENCESTER. REPRINTED, BY PERMISSION, FROM THE BATH AND WEST OF ENGLAND AGRICULTURAL JOURNAL. ^VOL.IIL LOIJDON: PRINTED BY W. CLOWES AND SONS, STAMFORD STREET, AND CHABING CROSS. 1855. ON THE VALUE OF ARTIFICIAL MANURES. ' If there ever was a time when the agriculturist had need to exercise especial caution in purchasing artificial manures, that time is the present ; for the practice of adulterating standard artificial fertilizers, such as guano, superphosphate of lime, nitrate of soda, &c., has reached an alarming point. The increasing demand for these manures, their inadequate supply, the general favour in which artificial fertilizers are now held by farmers, the deficiencies of natural sources from which a really valuable manure can be prepared; disregard for the difference of the practical effects of a manure and its real money- value ; the difficulty of arriving in a single season at a positive conclusion with regard to its efficacy, and other similar circum- stances, are fruitful causes of the shameful adulterations in arti- ficials of recognised value, and of the many inferior or worthless new compounds which are found in the manure-market at the present time. Some artificial manures are actually sold and bought at double or triple the price which they are worth. This is especially the case with certain saline compound manures. Some of these manures contain 30 to 40 per cent, of Avater, notwithstanding their dry appearance, which is easily accounted for by the fact that many salts in crystallising bind 50 per cent., or even more, water. A large quantity of a useless material thus remains concealed in the saline compound, into the com- position of which such salts largely enter, and thereby its value is greatly diminished. It is well known, moreover, to all who have watched the state of the manure-market how easily testimonials can be obtained even from high agricultural authorities, notwithstanding the com- parative inferiority of the manure. Indeed, the dealer or manu- facturer has so many chances to reap a large profit for a season from the sale of an all but worthless article that it is not sur- prising to find so many un^rupulous persons engaged in a course of fraudulent pursuits. Whilst thus on the one hand the unsuspecting farmer is swindled out of his money, and runs the risk of losing his crops too ; on the other hand, enterprising, well-qualified, and honest persons are deterred from employing their capital, energy, and skill in an undertaking which, under more favourable conditions, could not fail to benefit alike the b2 4 VOELCKER 071 the Value of Artificial Manures. manufacturer and purchaser. It is but right, however, to men- tion that it is far from us to censure indiscriminately the whole class of manure-manufacturers and dealers ; for we know many highly respectable fair-dealing and skilled parties who well deserve the support and encouragement of the agriculturist, and who are as anxious as every right-minded person to put a stop to the scandalous proceedings which are now and then revealed to us through the medium of the agricultural press, but which, alas ! but too often remain buried in darkness. During the past season we have had the opportunity of be- coming practically acquainted with several instances of gross fraud, which cannot fail to startle the unsuspecting. The pub- lication of several of the subjoined cases lately brought under our notice, we trust, will address a word of caution to the agricul- turist, and have the effect of protecting him from imposition, by helping to put a stop to the fraudulent dealings of the unprin- cipled, and by giving encouragement to the honest and skilful manufacturer of artificial manures. Before entering into details, huwever, we may be permitted to make a few general observations on the practical efficiency and commercial value of manures. The effects which a manure is capable of producing on vege- tation, it is evident, mainly depend on its constituents ; and as the composition of the various fertilizers usually employed for restoring the impaired fertility of the land greatly varies, their effects on vegetation necessarily must vary likewise considerably. In well-made farmyard manure all the elements are found which are required for the healthy and luxuriant growth of all the dif- ferent cultivated plants. Practical experience having shown that all the different kinds of vegetable products can be greatly increased by the application of farmyard-manure, it is justly esteemed as a universal manure. But this is not the case with many artificials, which, containing a preponderating amount of one or two fertilizing constitutents, and a deficiency of others, often fail to produce any marked effects on some crops, whilst their application to others is followed with the most beneficial results. Indeed, most artificial manures are characterised by a specific action : some exercise a highly beneficial effect on root- crops ; others on a grain-crop, or on pasture-land. Hence they are- called special manures. Thus, whilst superphosphate of lime produces striking results •on turnips and root-crops in general, its effects on wheat, oats, or barley are less apparent. Again, whilst nitrogenized and ammoniacal manures, such as guano, soot, nitrate of soda, animal refuse matters, &c., favour in a special manner the abundant produce of wheat, oats, or barley, they do not, like phosphatic manures, promote the de- velopment of bulbous roots, such as swedes or mangolds, to an Specific Elements of Manures — Nitrogen. 5 equal extent. A thorough knowledge of the composition of special artificials, and of the conditions under which they act most beneficially, is therefore of much value to the farmer, as it enables him to apply fertilizers of that description with the greatest advantage. There are, however, others which, notwith- standing the deficiency of some constituents, can be, and are, used successfully for various kinds of crops. In reality, the deficiency of some constituents, instead of being a defect, is a recommendation to these manures ; for several of the consti- tuents which greatly preponderate in farmyard-manure are present in most soils in abundant quantities ; they need not therefore be supplied to the land in the form of manure ; or should they be wanting in the soil, they can be readily obtained almost everywhere at a cheap rate. If, therefore, these inex- pensive and more widely-distributed substances are dispensed with in compounding a manure, and only those are selected which occur in soils in minute quantities only, a very valuable and efficacious fertilizer is obtained, which possesses the great advantage of containing in a* small bulk all the essential fertiliz- ing substances of a large mass of home-made dung. In one sense, all the fertilizing agents are alike valuable ; for they are all indispensable for the healthy condition of our cul- tivated crops, and consequently the absence of one is attended with serious consequences, though all others may be present in abundance. Thus the deficiency of lime in the land may be attended with as much injury as that of phosphoric acid. In this sense lime is as valuable as phosphoric acid ; but inasmuch as lime is generally found in most soils in abundant quantities, or, if deficient, can be applied to the land more economically in the form of slaked lime, marl, shell-sand, &c., its presence in an artificial manure is by no means a recommendation to it. The efficacy of manure therefore depends not only on its com- position but also on that of the soil, and let us add, likewise, on the requirements of the crops intended for cultivation. It is well, also, to bear in mind that the substances which soils gene- rally contain only in minute quantities are exactly those which plants require in much larger proportions than the constituents which abound in soils. The efficacy of a manure consequently depends in a great measure on the amount of the more rare and valuable consti- tuents. In estimating the probable effects of a manure, it is very important to entertain correct views with respect to the comparative value of the component parts of manures. It has been shown by practical experience that nitrogen in the form of ammonia or nitric acid, phosphoric acid, and potash are the most efficacious and valuable constituents of all manures. 1. Nitrogen — in the form of ammonia, nitric acid, or animal b3 6 VOELCKER on the Value of Artificial Manures. and vegetable matters— without doubt is the most valuable of all fertiliziuja: substances, and ought therefore to be present in every good artificial general manure. Ammonia, nitric acid, and more or less decomposed nitro- genized organic . matters, closely resemble each other in their action. They all exercise a peculiar forcing effect, especially when supplied to the plant at an early stage of its growth : at a later period they appear much less effective. For this reason nitrogenized manures, such as guano or soot, ought to be applied to wheat, either in autumn or early in spring, immediately after the young blade has made its appearance above ground. The effects of ammonia have been so well ascertained by numerous experiments in which it has been applied, with the exclusion of all other substances, that few practical men at the present time will hesitate to ascribe the rapid forcing effects of guano, soot, sulphate of ammonia, ammoniacal liquor of gas-works, &c., to the ammonia which they contain. These manures, as well as nitrate of soda and nitrates in general, in^ duce a luxuriant development of leaves, and may therefore be called leaf-producing manures. Grass-land, wheat, and other grain-crops are benefited by them in a striking manner ; but on account of their special action they ought to be used with caution in the case of corn-crops, and always more sparingly on light than' on heavy land ; otherwise, splendid straw, but little and an inferior sample of grain, will be obtained. As yet the question, whether nitrogen is more useful to plants in the form of ammonia or nitric acid, has not been decided. As the solution of this question is of considerable practical im- portance, it is very desirable that the relative effects of nitrates and ammoniacal salts should be ascertained by a series of well- conducted comparative field experiments. Animal and vegetable organic substances containing nitrogen in an unfermented state scarcely exhibit any fertilizing effects on vegetation; and it is only after their nitrogen has become changed into ammonia or nitric acid that they become powerful feitilizers. As the value of a manure depends in some degree on the rapidity of its effects, the nitrogen in fresh animal or vegetable substances is not quite so valuable as in the form of ammonia or nitric acid. Nitrogenized manures likewise appear to facilitate the assimilation of the mineral matters found in the ashes of plants. As our fields are generally deficient in ammo- nia or nitric acid, their presence in an artificial manure is of great importance. Nitrogen, moreover, in either of the stated combinations, is very expensive, and is therefore justly regarded as the most valuable ingredient of artificial manures. 2. Phosphoric Acid. — Next in value follows phosphoric acid. In artificial manures it generally exists in the form of bone- PhospJioric Acid — Potash. 7 earth or phosphate of lime. Like ammonia, phosphoric acid occurs in soils but in small quantities, and as it is required abundantly not only for grain and root-crops but for all vegetable produce raised as food for man or beast, the application of phos- phatic manures to nearly all crops is followed with beneficial results. Whilst, however, phosphoric acid benefits more or* less all the crops usually grown on the farm, it promotes the development of bulbous roots, such as turnips, carrots, mangold, &c., in an extraordinary manner. 3. Potash. — This alkali, also, is an important fertilizing con- stituent, inasmuch as it is largely required by all our cultivated plants, and frequently is deficient in soils. Root-crops, and her- baceous plants in particular, appear to require much potash ; for which reason turnips, carrots, and other green crops are much benefited by wood-ashes, burnt clay, and liquid manure, which all contain considerable quantities of soluble potash. Potatoes especially require a good supply of potash. Much less valuable constituents of artificial manures are soda, common salt, glauber salt, magnesia, lime, gypsum, oxide of iron and silica. Nitrogen in a proper state of combination, phosphoric acid and potash, thus principally determine the efficacy of a manure. We have seen, however, that the composition of the soil to which it is applied, and the requirements of the crop for which it is used, affect in a great measure the effects which an artificial manure is capable of producing. Other circumstances, such as a wet or a dry season, the time at which, and the mode in which, it is applied, likewise exercise a decided influence on the efficacy of a manuring substance ; and it remains, therefore, for the judicious farmer to determine whether the actual fertilizing effects of an artificial manure justify the expenditure of a certain amount of money or not. But there is another consideration to which we would direct special attention, as it is often overlooked alto- gether by the practical man. As many artificial manures are very efficacious, the purchasers of such manures are generally quite satisfied with the results, and do not trouble themselves with the inquiry, " At what price can I obtain the different fer- tilizing constituents in the manure separately ?" or in other words, what is its commercial value ? Hence we can explain that frequently fertilizing mixtures find purchasers at prices twice or three times as great as their intrinsic money-value. A few illustrations will show that the imme- diately apparent efficacy of a manure does not necessarily deter- mine its money-value. Nobody in his senses would think of paying the same price for lime as for guano ; and yet there are instances on record in which the parallel effects realised by lime were greater than those of guano. It does not follow, however, that lime possesses 8 VoELCKER on the Value of Artificial Manures. a greater commercial value than guano, because under peculiarly favourable circumstances it produces more beneficial results. Bones have been known to fail altogether on some soils, for the very obvious reason, that these soils contained already a more than sufficient supply of phosphates to meet all the wants of the plants, or because the closeness of the soil hindered the decomposition of the bone ; but surely failures of that kind do not imply that bone-dust is worth nothing. A few years ago we examined an artificial manure, which was sold at 8Z. per ton. Several testimonials from practical men expressed a very favour- able opinion of its merits. However, on analysis it was found to contain mere traces of ammonia and phosphoric acid, and no less than 88 per cent, of carbonate of lime, with some charred spent tanner's bark, and sand. It was in reality a mixture of road-scrapings with some charred tan refuse, and hardly was worth the carriage from London to Gloucester. Notwithstand- ing its exceedingly low commercial value, its efficacy on soils greatly deficient in lime was very marked. But it is evident that the beneficial effects it produced under certain favourable con- ditions did not entitle the manufacturer to demand the exorbitant price at which this manure was actually sold. Again, let us suppose the money-value of Peruvian and Saldanha-bay guano were to be determined by their effects on turnips. In this case Saldanha-bay guano, which is much richer in phosphates than Peruvian, would produce the heavier crop, and we would arrive at the absurd conclusion that Saldanha-bay guano was worth more money than Peruvian. Both guanos tried upon wheat would reverse the result ; for wheat is more benefited by am- monia than by phosphates ; and as Peruvian guano contains 16 per cent, of ammonia, and Saldh ana-bay only 4 to 5 per cent., we can readily explain the superior efficacy of the latter upon wheat. Does not this plainly show that the commercial value of guano does not necessarily depend on the effects which it is capable of producing on certain crops ? Indeed, for turnips the cheap Saldanha-bay guano is more valuable than the more ex- pensive Peruvian. Another instance brought lately under our notice may be men- tioned in illustration of the necessity of distinguishing between the practical effects of a manure and its commercial value. A guano, for which the full price of the best Peruvian was paid, on analysis was found to contain only 11 instead of 16 per cent, of ammonia and 14 J per cent, of sand. Now, though it was evi- dent that the commercial value of this guano was considerably re- duced by the latter impurity alone, we were told by the purchaser that he had obtained a better crop of wheat with this guano than with any other sample he had tried in previous years, and that he therefore considered it a first-rate article. « Commercial Valtie. . n:^m\v^{yj '9 These examples, we trust, will be amply sufficient to prove that the practical effects which a manure is capable of producing do not necessarily determine its money-value. The question, however, How much money is an artificial manure worth ? is one of paramount importance to the farmer ; and happily it is one the solution of which chemistry greatly facilitates. Any good analytical chemist can ascertain the exact amount of the different constituents of the manure, and, knowing the market-price at which they can be obtained separately, he is enabled to calculate with tolerable accuracy its commercial value. In chemical analysis the farmer therefore possesses a sure means of ascertaining, before effecting a purchase, whether the price demanded is reasonable or exorbitant. It would lead us too far to enumerate all the reasons which could be assigned for fixing the price of some of the more fre- quently-occurring manuring substances which follow. However useful the subjoined table may be to the practical man, considerable latitude must be allowed in estimating the real commercial value of an artificial manure ; and as all articles of commerce are sub- ject to considerable fluctuations, it follows necessarily that the price-list subjoined can have no permanent value: — Table for determining the Money value of Artificial Manures. 1. Nitrogen in the fonn of ammonia .. .. 8c?. per lb. 2. Nitrogen in animal or vegetable substances 6d. „ 3. Nitrate of soda 2d. „ 4. Phosphate of lime (bone-earth) Id. „ or phosphoric acid alone 2d. „ 5. Soluble phosphate of lime, or bi-phosphate of lime 4i^d. „ 6. Salts of potash 1^. ,, or potash alone 2d. „ 7. Gypsum Id. per 10 lb. 8. Lime 1 heat and the formation of fat j Inorganic matters (ash) . . 82-050 1-280 15-738 •932 7-27 87-54 5-19 87-338 -667 11-250 •745 5-268 88*442 6-290 , 100*000 100- 0) 100-000 100-000 A comparison of these numerical results with each other will show ; — 1. That there is a general resemblance in the composition of parsnips and carrots. Boots* 29 2. That parsnips, however, differ in composition from white carrots by containing less sugar, the deficiency of which is replaced by starch, a substance not occurring in carrots. 3. That white Belgian carrots generally contain 5 to 6 per cent, more water than parsnips. Thus fresh parsnips contain on an average 18 per cent, of solid substances, whilst fresh carrots on an average contain but 12 per cent. Hence the greater nutritive value of parsnips as compared with carrots. 4. That parsnips contain twice as much ready-formed fat as carrots. They ought, therefore, to be superior as a fattening material in the feeding of stock. 5. That the proportion of cellular fibre in parsnips is very much greater than in carrots. In both it is large. The cellular or woody fibre in parsnips, carrots, turnips, mangolds, and swedes, must not be regarded as useless in the p,nimal economy, for there can be little doubt that the soft and young fibres of these roots are readily converted in the stomach of animals into gum and sugar, and applied in the system to feed the respiration, or for the laying on of fat. Compared with turnips we find that parsnips contain 6 to 8 per cent, less water, and with mangolds 5 to 6 per cent. less. There is thus nearly twice as much dry solid matter in parsnips as in turnips, and consequently a ton of parsnips ought to go as far as a fattening material as two tons of white turnips. Mangolds. — Mangolds have been analysed by Professor Way, Johnston, Wolff, and myself, but as it will be of no practical utility to mention these various analyses in detail, I shall leave them unnoticed, and state at once the average composition of good mangold wurtzel, which has been calculated from 13 pub- lished analyses of this root : — Water Flesh-forming constituents Woody fibre Sugar Pectin, gum, &c Inorganic matters (ash) In Natural Calculated State. Dry. 87-78 1-54 12-60 1-12 9-16 6-10 49-91 2-50 20-45 •96 7-88 100*00 100-00 Mangolds, it will be observed, contain on an average as much water and dry matters as carrots, and, on the whole, are almost as nutritious as carrots, if they are given to fattening beasts after a few months' keeping. When newly taken out of the ground mangold wurtzels contain a peculiar acrid substance, which has Sd VOELCKER on the Chemistry of Food, a tendency to scour animals fed upon the fresh root. Although it has not yet been shown whether or not this acrid principle disappears on storing away mangolds for some time, it is a well known fact that, after a few months' keeping, mangolds have not this tendency to scour, and are much more nutritious than in a fresh state. The superior fattening value of stored mangolds, when compared with the fresh root, may be due to the absence of this acrid principle in old roots, but doubtless it must be attri- buted also to the larger amount of sugar ^hich stored mangolds contain. An examination of fresh and old mangolds, namely, has shown me that, on keeping, the pectin in the fresh roots is gradually transformed into sugar, which appears to be more conducive to the rapid fattening of beasts than pectin. For these reasons mangold wurtzel ought not to be supplied to animals before the latter end of December or the beginning of January. Before stating the composition of turnips and swedes I would draw attention to the remarkable fact, which perhaps may be new to some, that mangolds appear to be about the worst description of roots that can be given to sheep. Two years ago I found this to be the case, when feeding various lots of sheep, with a view of ascertaining practically the relative value of different feeding materials. For several days the sheep refused to eat the sliced mangolds, and were content with the small quantity of hay which was given to them at the same time, and only after 4 weeks they became in some degree reconciled to the taste of mangolds, but did not get on well upon this food. Although these sheep were supplied with a fixed and limited quantity of hay, and as much sliced mangolds as they would eat, I found at the end of four months that they had not increased a single pound, whilst my experimental sheep fed upon swedes and hay increased on an average at the rate of 2^ lbs. per week. On further inquiry I have learned that this observation is confirmed by many practical feeders. Mangolds, therefore, ought not to be given to sheep. This peculiarity of mangolds thus shows that a feeding substance which, like this root, is justly esteemed on account of its fattening properties when given to beasts, may not possess any great nutritive value when given to sheep. Another direct proof is here afforded of the fact, that the chemical composition of food does not solely determine its adaptation to a particular purpose, for, like mangolds, other feeding materials may be rich in nutri- tive substances, and valuable when given to fattening beasts, whilst it does not agree at all with the constitution of sheep. Turnips and Swedes. — The composition of different kinds of turnips, and consequently their nutritive value, present us with great variations. But inasmuch as one and the same variety, when grown upon different soils, often presents us with quite as great variations in the amount of the various constituents which are found in general in turnips or swedes, we cannot attach a Roots. 31 fixed nutritive value to each variety of turnip. Indeed practical experience has shown that in one locality a particular kind of turnip succeeds better, and is found to go further as an article of food, than another variety, whilst the same kind of turnip which is much appreciated in one place is held in very low estima- tion by the farmers of another district. It is thus, strictly speaking, incorrect to pronounce one kind of turnip to be always less or more nutritious than another. The following table exhibits at a glance the variations that we meet with not only in the com- positions pf different kinds of turnips, but also in that of one and the same kind. Table showing the Proportion of Water, Solid Matter, Flesh-forming Substances, and Ash, in different kinds of Turnips. 'Purple-top yellows, grown in East Lothian in 1849: With farmyard manure With farmyard manure and guano . . With guano alone Aberdeen yellows, grown in Perthshire : In 1849, on clay land „ on black do ,, on hill do In 1850, on clay do „ on black do. „ on hill do White globe turnips, grown in Lothian in 1849: With farmyard manure With farmyard manure and guano . . With guano alone Swedes grown in Perthshire : In 1849, on clay land „ on black do „ on hill do In 1850, on clay do „ on black do „ on hill do /^ Swedes grown at Cirencester in 1852 1853 White globe, grown at Cirencester in Norfolk bell 1852 Percent- age of Water. 91-20 89-72 92-50 91-19 90-47 90-57 94-26 90-59 93-99 91-41 92-20 92-85 90-58 88-78 87-12 92-73 92*78 92-78 89*80 89-46 91-00 86-15 86-33 87-20 87-40 88-11 88-35 88-60 87-28 89-96 90-43 90-38 92*28 Percent- age of Dry Matters. 8-80 10-28 7*50 8*81 9-53 9-43 5*74 9*41 6*01 8-59 7-80 7-14 9-42 11*22 12*88 7-27 7-22 7*22 10-20 10-54 9-00 13-85 13-17 12-80 12*60 11-89 11-65 11*40 10*72 10*04 9-57 9-62 7*72 Percent- age of Flesh- forming Matters. 1-127 1-581 1-060 1*217 1*094 1*769 •681 1*044 •962 1-358 1-198 1-279 *987 1*137 1*781 *769 -619 •919 1-174 1-443 2-006 1-862 1*875 1-712 1-643 1*593 1-737 1*593 1*712 1*143 1-737 Percent- age of Ash. •63 •64 •64 •910 •838 •830 •744 •623 •635 •654 •641 •5.58 *655 *628 •498 *548 *516 •639 *628 •620 1-021 32 VOELCKER on the Chemistry of Food, Gn account of these variations, which are often observed in one and the same species of turnips, it is difficult to fix precisely the nutritive value of these roots. The following average analyses must, therefore, be regarded simply as illustra- tions of the proximate composition of some kinds of turnips : — Proximate average Composition of some kinds of Turnips. Analysed by Dr. Voelcker. Analysed by Dr. Anderson. White Globe. Norfolk Bell. Swedish Turnip. Purple-top Yellows. Aberdeen Yellows. Water Flesh-forming substances Fatty matters Sugar, pectin, gum, &c. Woody fibre Inorganic matters (ash) 90-430 1-143 not 5-457 2-342 •628 92-280 1^737 deter 2-962 2-000 1-021 89-460 1-443 mined. 5-932 2-542 -623 91-200 1-117 •103 90*578 1-802 •441 4-333 2-607 •640 4-181 2-349 •649 100-000 100-000 100-000 100-000 100-000 On an average, turnips thus contain from 89 to 92 per cent, of water, and 8 to 12 per cent, of dry solid matter. Swedes, usually, though by no means always, contain less water than any other variety of turnips ; they are generally firmer and keep better than white turnips. On the whole swedes are more nutritious than other species of this root. In white and yellow turnips the percentage of water is generally higher, and averages 90 or 91 per cent. The nutritive value of turnips is often estimated by the amount of nitrogen which they contain. The best roots, however, do not always contain a very high percentage of nitrogen, and it is therefore impracticable to determine the nutritive value of these roots by the amount of nitrogen which they contain. Mr. Lawes, of Rothamsted, indeed, has shown lately in some well-conducted feeding experiments, that those turnips which are richest in nitrogen are by no means the most nutritious. The influence which the soil exercises on the qualities of swedes and turnips is well known to practical men. Thus roots grown on peaty or very stiff clay soils are not near as good as others of the same kind grown on good turnip loam. The climate and season likewise in a remarkable degree affect the qualities of turnips. As these roots succeed best in a moist climate, we can explain why they produce a more abundant and nutritious crop in Scotland than in the south of England. Another circumstance which affects the qualities of turnips is the mode of growth. Roots grown rapidly, generally speaking, are not as nutritious, and do not keep so well as turnips, the growth of which is not forced so rapidly by stimulating manures. ^ Roots — Grasses. '■' 33 It has been asserted that turnips grown with guano are less nutritious than those grown with farmyard manure, and Dr. Anderson's analyses indeed appear to countenance this very pre- valent opinion. However, this must be received with considerable latitude, for although it is quite true that many turnips grown with guano are very watery, and therefore not very nutritious, it does not follow that invariably roots grown with farmyard manure are more valuable. It depends entirely on the nature of the soil and the quantity of guano employed, whether a watery root is produced or not. As far as our present experience goes, it would follow that a crop of turnips raised entirely by means of a large amount of Peruvian guano is watery, and does not keep well ; whereas no difference in the qualities is observed in roots grown with farmyard manure and turnips raised with guano, if this manure is sparingly employed and the land is in good condition. Peruvian guano, moreover, for economical reasons, ought not to be used in large quantities for raising a crop of turnips, as it is apt to produce abundance of tops at the expense of the bulbs. The cheaper Saldanha Bay guano, how- ever, which contains a very large amount of phosphates, or those constituents which benefit root-crops in a special manner, may be used with advantage, and no fear need be entertained that this description of guano will produce a watery root. 7. Gree]^ Food (Natural Grasses). — The nutritive value of the various natural grasses and of green food in general was for- merly determined simply by ascertaining what preparation of substances, soluble and insoluble in water, green food contained. The green food was considered the more nutritious, the greater the proportion of substances which it yielded to water. In this way Sinclair endeavoured to determine the nutritive value of most natural and artificial grasses. The method employed by Sinclair, however, is very defective, and yields results which are incon- sistent with practical experience. Sinclair's method of analysis and results thus are obsolete, and have to be rejected. The more refined methods of chemical investigation with which we are at present acquainted, and the increased knowledge of the process of nutrition, have enabled Professor Way to supply the agriculturist with a series of trustworthy analyses of most natural and artificial grasses. The details of this important investigation are recorded in the * Journal of the Royal Agricultural Society of England/ 1853, part i., p. 171. The following tables exhibit the composition of a number of the most frequently occurring natural grasses in a recent state and in a dried condition : — u VOELCKER on the Chemistry of Food. Natural Grasses in a Fresh State. Anthoxanthnm odoratum — Sweet-scented vernal grass Alopecurus pratensis — Meadow foxtail-grass Arrhenatherum avenaceum — Common oatlike grass . Avena flavescens — Yellow oatlike grass , , pubescens — Downy oat-grass Briza media — Common quaking-grass Bromus erectus — Upright brome-grass , , mollis — Soft brome-grass Cynosurus cristatus — Crested dogstail-grass . . . . Dactylus glomerata — Cocksfoot-grass Ditto, seeds ripe Festuca duriuscula — Hard fescue-grass Holcus lanatus — Soft meadow-grass Hordeum pratense — Meadow barley Lolium perenne — Darnel grass , , italicum — Italian rye-grass Phleum pratense — Meadow catstail-grass . . . . Poa annua — Annual meadow-grass , , pratensis — Smooth-stalked meadow-grass . . . ,, trivialis — Rough-stalked ditto . . . Grass from water-meadow Ditto, second crop Annual rye-grass Water. 80-35 80-20 72 -PS 60-40 61-50 51 '85 59-57 76-62 62-73 70-00 52-57 69-33 69-70 58-85 71-43 75-61 57-21 79-14 67-14 73-60 87-58 74-53 69-00 Albu- minous or Flesh- forming Prin- ciple. 2-00 2-44 3-54 2-96 3-07 2-93 3-78 4-05 4-13 4-06 10-93 3-70 3-49 4-59 3-37 2-45 4-86 2-47 3-41 2-58 3-22 2-78 Fatty Matters •67 -52 -87 1-04 •92 1-45 1-35 •47 1-32 -94 •74 1-02 1-02 -94 •91 -80 1-50 •71 -86 •97 •81 -52 Respi- ratory Prin- ciples : Starch, Gum, Sugar. 8-54 8-59 11-21 18-06 19-16 22-60 33 9^04 19^ (54 i3-;^o 12-61 12-46 11-92 20-05 12-08 14-I1 22-85 10-79 14-15 10-.54 3-93 11-17 12-89 Mineral Woody Matter Fibre. or Ash. 7-15 1-24 6-70 1-55 9^37 2-36 14-22 2-72 13-34 2-01 17-00 4-17 19 2-11 8-46 1-36 9-80 2-38 10-11 1-54 20-54 2-61 11-83 1-66 11-94 1-93 13-03 2-54 10-06 2-15 4-82 2-21 11-32 2-26 6-3(1 -59 12-49 1-95 10- 11 2-20 3-13 1-28 8-76 2-24 12-47 1-99 Natural Grasses in a Dry State. Anthoxanthum odoratum — Sweet-scented vernal grass Alopecurus pratensis — Meadow foxtail-grass Arrhenatherum avenaceum — Common uatlike grass . Avena flavescens — Yellow oatlike grass , , pubescens — Downy oat-grass Briza media — Common quaking-grass . . . . . Bromus erectus — Upright brome-grass , , mollis — Soft brome-grass Cynosurus cristatus — Crested dogstail-grass . . . . Dactylis glomerata — Cocksfoot-grass Ditto, seeds ripe Festuca duriuscula — Hard fescue-grass Holcus lanatus — Soft meadow-grass Hordeum pratense — Meadow barley Lolium perenne — Darnel grass , , italicum — Italian rye-grass Phleum pratense — Meadow catstail-grass . . . . Poa annua — Annual meadow-grass ,, pratensis — Smooth-stalked meadow-grass . . . ,, trivialis — Rough-stalked ditto . . . Grass from water-meadow Ditto, second crop Albuminous or Flesh- Fatty forming Matters. Principle. 10-43 3-41 12-32 2-92 12-95 3-19 7-48 2-61 7-97 2-39 6^08 3-01 9-44 3-33 17-29 2-11 11-08 3-54 13-53 3-14 23-08 1-56 12-10 3-34 11 •sa 3-56 11^17 2-30 11^85 3-17 10-10 3-27 11-36 3-55 11-83 3-42 10-35 2-63 9-80 3-67 25-91 6-53 10-92 2-06 Respiratory Principles : S>tarch, Gum, Sugar. Woody Fibre. 43-48 43-12 38-03 47-08 49-78 46-95 38-66 52-64 44-32 26-53 40-43 39-25 46-68 42-24 57-82 53-35 51-70 43-06 40-17 32-05 43-90 82-02 33-36 33-83 34-24 35-95 34-64 35-30 '36-12 26-36 33-70 43-32 38-71 39-30 31.67 35-20 19-76 26-46 30-22 38-02 38-03 25-14 34-30 In explanation of these tables, it may be observed that most of the grasses here mentioned were analysed when in flower ; they were collected in 1849 from meadows in the neighbourhood of Cirencester. Natural and artificial grasses are much more nutritious when in Grasses. 35 a young state than at the period when they are in full flower, inasmuch as the woody fibre increases towards the period of maturity so extremely rapidly, that often a few days' difference in the time of cutting grass for hay greatly affects the nutritive value of tiie latter. For this reason, perhaps, it would have been better to submit all the grasses to analysis at haymaking time. How- ever, a good many grasses have been examined at that period, and we are thus enabled to form an opinion of the qualities of the hay which these grasses will produce. The differences exhibited in the above-mentioned analytical results are considerable in some instances, and clearly point out the inferiority of some grasses. It must be borne, however, in mind, that the same grass which here has furnished a large amount of woody indigestible fibre and little fat or albumen, when grown on another soil or reaped earlier, will, no doubt, give different results. We require, indeed, a large number of analyses of grasses before we can speak decisively of the comparative nutritive value which they severally possess. Still Professor Way's analyses afford useful indications respecting the feeding value of some natural grasses, especially if we assume in each the same amount of water. Hay on an average contains 14*3 per cent, of water. If we calculate the above results by assuming in each case 14'3 per cent, of moisture, we obtain the composition of the hay which each grass would produce. The subjoined table in which this calculation has been intro- duced enables us still better to compare the relative merits of these grasses : — Composition of Hay, containing 14*3 percent, of Water. Flesh- forming Matters. Anthoxanthum odoratnm — Sweet-scented vernal grass 8'94 Alopecurus pratensia — Meadow foxtail-grass . . . 10' 56 Arrhenatherum avenaceum — Common oatlike grass . 11*10 Avena flavescens — Yellow oatlike grass 6*41 ,, piibescens — Downy oat-grass ...... 6*83 Briza media — Common quaking-giass 5*21 Bromus erectus — Upright brome-grass 8*09 ,, mollis — Soft brome-grass . ...... 14"82 Cynosurus cristatus — Crested dogstailgrass .... 9 "51 rhleum pratense — Meadow catstail-grass .... 9 '74 Dactylis glomerata — Cocksfoot-grass 11 '60 Ditto, seeds ripe 19-78 Festnca duriuscula — Hard fescue-grass I 10*37 Holciis lanatus — Soft meadow-yrass I 9*87 Hordeum pratense — Meadow barley j 9*57 Lolium perenne — Darnel grass 10*16 ,, italicum— Italian rye-grass , | 8*66 Poa annua — Annual meadow-grass i 10*14 ,, pratensis — Smooth-stalked meadow-grass . . . ' 8*87 ,, trivialis — Rough-stalked ditto ... 8*40 Grass from water-meadow 22'2i Ditto, second crop 9*36 Mean 9*40 Fat. 2-92 2*50 2-73 2*24 2*05 2*58 2-85 1*81 2-83 3*04 2*69 1-34 2*86 3*05 1*97 2-72 2*80 2*93 2*:^ 3*15 5*»^0 1-77 2-36 Respi- ratory Principles, 37*27 36*96 32*60 40*35 42*67 40*24 70' 33*14 45*12 45*73 37*99 22-74 34*65 33*64 40-01 36*21 49*56 44-30 3.-. -88 34-43 27*47 37-63 38-34 Woody Fibre. 30 31-17 29-00 29-35 30-81 29-69 30-26 I 30-96 22-59 22*68 28-89 37*13 33-18 33- (9 27-15 30-17 16-94 25-90 32-59 32-60 21 -JS 29*40 29*:4 Ash. 5-42 6*69 9*93 5*90 4*47 7*42 4-47 4*99 5*47 4*53 4-55 4-72 4-65 5-46 5-30 6-46 7-76 2-43 5*09 7*14 9*03 7*56 I v 84 a& VOELCKER on the Chemistry of Food. According to these analyses, the natural grasses may be grouped together in the following three classes, which, however, are not separated from each other by definite lines of demarkation : — Grasses of Superior Quality. Grasses of Medium Quality. Grasses of Inferior Quality. Lolium italicum — Ita- Anthoxanthum odoratum Avena flavescens — Yellow lian rye-grass. — Sweet-iscented vernal oat-like grass. Poa annua — Annual grass. Avena pubescens— Downy meadow-grass. Alopecurus pratensis — oat-grass. Hordeum pratense — Meadow foxtail grass. Briza media — Common Meadow barley. Arrhenatherum avena- quaking-grass. Cynosuras cristatus — ceum — Common oat- Bromus erectus— Upright Crested dogstail-grass. like grass. brome-grass. Dactylis glomerata — Lolium perenne— Darnel Festuca duriuscula— Hard Cocksfoot-grass. grass. fescue grass. Bromus mollis — Soft Poa pratensis — Smooth- Holcus lanatus— Soft mea- brome grass. stalked meadow-grass. dow-grass. Phleum pratense — Mea- Poa trivialis — Rough- dow catstail-grass. stalked meadow-grass. The above analyses refer to grasses in a wild state ; in a cul- tivated condition there can be no doubt many will exhibit a different composition. Thus I found in a specimen of Italian rye-grass, grown on a well-manured soil, 1275 per cent, of flesh- forming substances and 8*61 per cent, of ash, calculated for the substance in an air-dry state, whilst Professor Way obtained only 8*66 per cent, of flesh-forming matters and 7*76 per cent, of ash in the analysis of air-dry Italian rye-grass, grown in a wild state. It is further worthy of observation that the grasses of irrigated meadows are much more nutritious than those of non-irrigated meadows. This, no doubt, is due to the disappearance of inferior grasses from irrigated meadows, but perhaps also to the circum- stance that the grass on such meadows is always cut earlier than on ordinary meadows. 8. Artificial Grasses. — Under this head we have to consider the composition of the various kinds of clover, sainfoin, lucerne, vetch, rib-grass, Burnet, and of millefoil. We possess three series of analyses of artificial grasses. The most complete series has been undertaken by Professor Way, the second by Dr. Anderson (in ' Transactions of Highland Society,* March, 1853, p. 440), and the third by myself (in ' Journal of Highland Society,' July, 1853, p. 56). As these are 'the only analyses that have been made with artificial grasses, and as the results obtained by Way, Anderson, and myself somewhat differ, I shall give the analyses of each experimenter separately in a tabu- lated form : — Grasses. 37 Composition of Artificial Grasses in Natural State. By Professor Way. Albu- Respi- mmous ratory Prin- ciples: Starch, Gum, Mineral Date Water. Flesh- forming Prin- Fatty Matter. Woody Fibre. Matter or Ash. of Collec- tion. cipks. Sugar. Trifolium pratense — Red clover .... 81-01 4-27 -69 8-45 3-76 r82 June 7 , , pratense perenne — Purple clover 81-0O 3-64 •78 8-04 4-91 1-58 ,, 4 , , incarnatum — Crimson clover . 82-14 2-96 •67 6-70 5-78 1-75 .. 4 ,, medium— C.'ow-grass . . 74-10 6-30 •92 9-42 6-25 3-01 y, 7 Ditto, second specimen 77-57 4-22 1-07 11-14 4-23 1-77 ,, 21 Trifolium procunlbens— Hop trefoil 83-48 3-39 •77 7-25 3-74 r37 ,, 13 repens— White trefoil . . 79-71 3-80 •89 8-14 5-38 2-08 ,, 18 Vicia sativa— Common vetch . . . 82-90 4-04 •52 6-75 4-68 Ml ,, 13 , , sepium — Bush vetch 79-90 4-64 •58 6-66 6-24 1^98 9 Onobrychis sativa— Sainfoin . . . 76-64 4 32 •70 10-73 5-77 P84 ,, 8 Medicago lupulina— Black medich . 76-80 5-70 •94 7^73 6-32 2-51 ,, 6 ,, sativa— Lucerne . . . 69-95 3-83 •82 13-62 8-74 3-04 Plantago lanceolata — Rib-grass 84-75 2-18 •56 6-06 5^10 1-35 May 28 Poterium sanguisorba— Burnet . . 85-56 2-42 -58 6-85 3^44 1-15 Achillea millefolium— Millefoil . . 10-34 2-51 45-46 32-69 9-00 ,, 79-68 3-98 0-75 8-39 5-31 1-88 The following analyses of various kinds of clover were made by Dr. Anderson. The clovers were grown in the garden of Messrs. Lawson, of Edinburgh. The specimens submitted to analysis were collected when the plants had come into full flower, which was, in the case of crimson clover, in the middle of August, and in the case of the rest, in the middle of September : — Composition of different kinds of Clover. By Dr. Anderson. Red clover— Trifolium pratense : 1. From F]nglish seed 2. From German seed (from the Rhine) 3. From French seed ...... 4. From American seed 5. From Dutch seed Cow-gi-ass — Trifolium medium: Variety, Duke of Norfolk , , common Crimson clover — Trifolium incarnatum: From French seed Yellow clover — Medicago lupulina: From English seed , . From French seed Lucerne — Medicago sativa Percentage in the Fresh Clover. Water. 81-76 82-56 77^38 78-60 80-13 Dry Sub- stances. 14-70 18-32 16-49 21-02 22 61 18-24 17-44 22-62 21-10 19-87 Ash. 1-30 1-49 1-95 1^58 2^73 1^92 1^88 £•02 1^75 2^49 Nitro- genized Sub- stances. 2-31 2-81 2-25 2-87 2-25 3^19 3-25 3^50 •^•94 b-06 Percentage in Dry Clover. Ash. 8-90 8-15 11-82 8-05 8-82 12-09 10-53 10-81 8^95 8-18 11-77 Nitro- genized Matters. 15-87 15-50 13-56 12-43 10-19 14-37 18-56 15-44 13-69 15-50 The artificial grasses analysed by myself were all grown in small beds of the same unmanured field at Cirencester, and the specimens were collected in August and September, just at the time when they began to enter into flower. The following table contains the results of this investigation :'• — P 2 38 VoELCKER on the Chemistry of Food. a. Composition of Artificial Grasses in Natural State. By Dr. Voelcker. I. Red Clover. II. White . Clover. III. Yellow Clover. IV. Alsike Clover. V. Bokhara Clover. VI. Lucerne. VII. Sainfoin. vni. Vetcb. EC Plantain Water 80-64 6-35 1-55 11-04 -42 83-65 4-98 1-13 9-80 0-44 77 57 8-26 1-40 12-17 0-60 76-67 4-91 1-33 16-36 0-73 81-30 6-80 1-54 10-01 •35 73-41 9-43 2-33 14-08 0-75 77-32 8-00 1-20 12-95 0-53 82-16 6-07 1-07 10-23 0-47 80-/9 Soluble in water— a. Organic substances . . b. Inorganic substances . . Insoluble in water— a. Impure vegetable fibre . &. Inorganic matters (ash) . 8-38 1-26 9-00 0-57 100-00 100-00 100-00 100-00 100-00 100-00 100-00 100-00 100-00 h. Constituents arranged in Groups. Water 80-640 3-606 13-:84 1-970 83-65 4-52 10-26 1-57 77-570 4-481 15-949 2-000 76-670 4-825 16-445 2-OGO 81-300 3-281 13-529 1-890 73-41 4-40 19-11 3-08 77-320 3-512 17-438 1-730 82-16 3-56 12-74 1-54 80-790 Flesh-forming matters .... Heat and fat producing substances Inorganic matters (ash; . . . 2-481 14-8;)9 1-830 100-000 100-00 100-000 100-000 100-000 100-00 100-000 100-00 100-000 a. Composition of Artificial Grasses in Dry State. Soluble in water— a. Organic substances. . . b. Inorganic substances . . Insoluble in water— o. Impure vegetable fibre . b. Inorganic matters (ash) . 32-79 8-01 57-02 2-18 30-46 6-91 59-94 2-69 36-83 6 24 54-26 2-67 21-05 5-70 70-13 3-12 36-36 8-23 53-53 1-88 35-47 8-76 52-95 2-82 35-28 5-29 57-09 2-34 34-02 5-99 57-35 2-64 43-64 6-55 46-85 2-96 100-00 100-00 100-00 100-00 100-00 100-00 100-00 100-00 100-00 Flesh- forming substances . Heat and fat producing matters Inorganic substances (ash) b. Constituents arranged in Groups 18-64 71-17 10-19 28-31 62-09 9-60 20-00 71-09 8-91 20-69 70-49 8-82 17-56 72-33 10-11 16-56 71-86 U-58 15-50 76-87 7-63 20-00 71-37 8-63 100-00 100-00 100-00 lOO-OO 100-00 100-00 100-00 100-00 In explanation of these results it is to be observed that the crude woody fibre constitutes the part insoluble in water. It cannot, therefore, be compared with the woody fibre obtained in Professor Way's analyses. A comparison of the artificial with the preceding natural grasses shows that the former, on the whole, contain more water, but at the same time a larger amount of flesh-forming constituents, than the latter. It will be observed that the proportions of water and dry nutritive matter, as well as that of flesh-forming con- stituents, in different species of artificial grasses, vary in some instances considerably. Similar differences are observed in some of the analyses of one and the same kind of clover, as recorded by Professor Way, Dr. Anderson, and myself. Thus, for instance. Grasses. 39 we meet with the following differences in one and the same species of clover : — Percentap^e of Water in Fresh State. Percentage of Flesh-forming Substances in Dry State. Highest. Lowest. Highest. Lowest. Red clover — Trifolium pratense 85-30 79-98 22-194 12-46 (Anderson.) (Anderson.) (Way.) (Anderson.) Cow-grass — Trifolium medium 81-76 74-10 20-968 10-19 (Anderson.) (Way.) (Way.) (Anderson.) White clover — Trifolium repens 83-65 79-71 27-31 18-45 (Voelcker.) (Way.) (Voelcker.) (Way.) Lucerne— Medicago sativa 80-13 65-95 16-56 12-56 (Anderson.) (Way.) (Voelcker.) (Way.) Sainfoin— Onobrychis sativa . . 77-32 1 76-64 18-17 15-50 (Voelcker.) 1 (Way.) (Way.) (Voelcker.) The percentage of water in the various clovers on an average amounts to : — Per Cent. According to Anderson 80-83 „ Voelcker 78-65 „ Way 78-24 The amount of flesh-forming substances in the dry clovers on an average is — According to Anderson 14-40 „ Voelcker 19-44 Way 19-31 I purposely abstain from drawing any practical deductions from these analyses ; for although they show that some species of clover are more nutritious than others, it does not follow that this will be the case under all circumstances. It indeed appears to me tliat the quality of the clover depends not so much upon the species cultivated as upon the time when it is cut down, and on the nature of the land on which it is grown. On one kind of soil, it is more than probable that a particular species of clover will delight more than another, and that consequently a great difference in the nutritive value of the same kind of clover will be observed when cultivated on land naturally suited for it or otherwise. The period at which clover is cut down especially affects its value. It has been observed already that young clover is always richer in flesh-forming substances, and contains less woody fibre than old clover, for which reasons it is more nutri- tious. Under the head of clover-hay, I shall mention the details of some direct experiments made in 1851 by Stockhard and Hell- riegel, which show how great is the influence of the time of cutting clover for hay on its nutritive qualities. Green Rye and Rape. — The following table represents the proximate composition of green rye and rape in a fresh and in a 40 VoELCKER on the Chemistry of Food. dried state. BotU the rye and rape were grown on a calcareous soil near Cirencester, and analysed by myself : — Composition of Green Rape and Rye. By Dr. A. Voelcker. Water Solid substance, consisting of : Woody fibre Ash united with fibre Insoluble albuminous compounds Soluble albumen Gum and pectin Salts insoluble in alcohol Sugar Salts soluble in alcohol Fatty matters, with a little chlorophyll Green Rye. In Natural State. 75*423 24-577 10-488 -418 -894 1-811 4-449 •572 4-685 •368 •892 100-000 Calculated Dry. 100-00 42-674 1-701 3'638 7*369 18*102 2-327 19*062 1-499 3-628 100-000 Green Rape. In Natural Calculated State. Dry. 87-050 (12-950) 3-560 *432 1*493 1-640 1-729 •990 2-218 •186 •649 99-947 27*490 3-335 11-529 12-664 lo*351 7*645 17-622 1*435 5-016 99*587 Rape-leaves, like cabbage, contain moreover a considerable quantity of sulphur and phosphorus, in a peculiar state of organic combination. In two different samples of rape the percentage of sulphur and phosphorus was found, for the dry substance — Phosphorus Sulphur 79 84 II. ■87 73 Average. 83 78 The dry leaves thus contained nearly one per cent, of sulphur, and an equal amount of phosphorus in organic combination. Arranged into groups according to the chief classes of alimentary principles, the composition of green rye and rape may be repre- sented as follows : — Water Nitrogenized substances (flesh-form-) ing constituents) j Non-nitrogenized matters — a. Woody fibre b. Fatty matters c. Respiratory substances . . Inorganic matters (ash) Green Rye. Green Ra}>e. In Natural State. Calculated Dry. In Natural State. Calculated Dry. 75-423 .. 87-050 .. 2-705 11-007 3-133 24-193 10-488 -892 9*134 1-358 42*674 3*628 37*164 5-527 3-560 •649 4-000 1-608 27-490 5-016 30-886 12*415 100-000 100-000 100-000 100-000 Green-leaf Food. 41 These analytical results give rise to several observations : — 1. It will be seen that rape is much more nutritious than green rje, and contains as large a proportion of flesh-forming constitu- ents as the best kinds of food which are used in a green state. 2. But not only is rape rich in flesh-forming matters, but it contains also a considerable quantity of oily or fatty matters. It will be observed that the fresh leaves contain of these fatty matters more than a half per cent., and the perfectly dry substance about five per cent. So large a proportion of fatty matters, as far as I know, does not occur in any other green food. The occurrence of so considerable a quantity of fatty matters explains at once, in an intelligible manner, the high fattening properties which distinguish rape as a sheep-feed. Rape requires to be grown on good land. In poor soils it never comes to anything, and it is not worth the trouble of culti- vating. On land of moderate fertility, or on good rich land, an occasional crop of rape, I am inclined to believe, would supply the farmer with a larger amount of feeding material than is afforded in a crop of turnips grown under the same circumstances. Weight for weight, rape is richer in flesh-forming matters, and especially in fatty substances, than turnips ; and as a crop of rape per acre is often heavier than a turnip crop, the more extended cultivation of rape appears to be desirable wherever it is admis- sible to introduce it. With respect to the feeding value of green rye, it appears, according to the above analyses, that it is inferior to the better sorts of clover. White Mustard {Sinapis alba), and Prickly Comfrey {Sym- phytum asperrimum). — The general composition of these two kinds of green food has been ascertained by me to be as follows i — a. Composition in 100 parts. 1 White Mustard. | i Prickly Comfrey. Leaves. Stem. In Natural state. In Natural State. Calcu- lated Dry. In Natural State. Calcu- lated Dry. Water 87-40 6-70 1-81 3-86 •23 53-18 : 14-36 1 30-63 • 1-83 88-40 1-61 •87 8-00 1-12 13-89 7-50 68-97 9-64 94-74 1 5-26 Soluble in water— a. Organic matters b. Inorganic matters (ash) . Insoluble in water— a. Impure ve{,'etal>le fibre 6. Inorganic matters (ash) . • • 100-00 100-00 100-00 j 100-00 100-00 100-00 100-00 42 VOELCKER on the Chemistry of Food. b. Constituents arranged in Groups. Water Flesh-forming substances .... Non-nitrogenized substances — Heat and fat producing matters . Inorganic matters (ash) . . . Prickly Comfrey. licaves. Stem. In Natural State. Calcu- lated Dry 1 .n Natural State. Calcu- lated Dry. In Natural State. Calcu- lated Dry. 87-400 3-287 7-273 2-040 26-12 57-69 16-19 1 88-400 2-712 ; 6-898 i 1-990 23-37 59-49 17-14 94-74 -69 3-81 -76 13-06 72-49 14-45 100-000 100-00 1 100-000 100-00 100-00 100-00 Tiie white mustard is an excellent green fodder, which is given with much advantage to sheep. It grows very rapidly, and may therefore be sown, when circumstances allow, as a catch-crop. In the fresh state mustard contains a large amount of water, and in comparison with the fibre, a much greater proportion of soluble substances than most kinds of green food. Notwithstanding the large proportion of water, white mustard is rich in flesh-producing substances, which fully explains its value as a feeding material. The prickly comfrey (Symphytum asperrimum) is a native of the Caucasus, from whence it was introduced into England in 1811, as an ornamental plant, by Messrs. Loddige of Hackney. More recently, the cultivation of comfrey has been recommended as affording a cheap and nutritious green food for cattle. The prickly comfrey is a beautiful perennial plant, with reddish-blue flowers. It grows to a great size, and may be cut down several times in one season, as it throws out new leaves again, and shoots very rapidly when cut down a few inches above the ground. At first cattle do not like it much, on account of the prickly nature of its leaves ; but by and by they get accustomed to this food, and then do pretty well upon it. In its fresh state, comfrey contains still more water than white mustard ; but notwithstanding this large proportion of water, the amount of flesh-forming substances is considerable. The juice of this plant contains much gum and mucilage, and but little sugar. Cabbage {Brassica oleracea); Cauliflower {Brassica botrytis) ; Mangold Leaves ; Turnip Tops. — The following tables give the general composition, as ascertained by myself, of these substances in a fresh and in a dried state : — Green-leaf Food, a. Composition in Natural state. 4a Cabbage. CauUflower. Mangold. Tops of Swedes. Tops of Norfolk- beU Turnips. Water 86-28 6-26 1-61 5-59 -26 leaves. 89-01 5-57 -69 4-57 -16 flower. 88-600 5-786 -740 4-760 •114 leaves. 91-960 I 8-040 88-367 3-699 1-984 5-638 •312 91-284 Soluble in water— a. Organic substances .... b. Inorganic substances (ash) . . Insoluble in water— o. Impure vegetable fibre . . . h. Inorganic matters (ash) . . . 3-104 1-225 4-092 •295 100-00 100-00 100-000 100-000 100-000 100-000 h. Constituents arranged in Groups. Water 86-28 1-87 89-01 88-600 3-61 3-844 6-53 6-702 -85 -854 91-960 1-764 4-984 1-292 88-367 2-087 7-250 2-296 91-284 Flesh-forming substances Heat and fat producing substances . . Inorganic matters (ash) 2 456 4-740 1-520 100-00 100-00 100-000 100-000 100-000 100-000 a. Composition of Dry Suhstances. Soluble in water — o. Organic substances . . . 6. Inorganic substances (ash) Insoluble in water — a. Impure vegetable fibre b. Inorganic matters (ash) . 45-62 11-74 40-74 1-90 100-00 50-53 6-40 41-57 1-50 50-700 41-700 1-000 100-00 I 100-000 100- 3^794 17^054 48-470 2-6t52 100- I 100-000 35-613 14-055 46-948 3-384 100-000 h. Constituents arranged in Groups. Flesh-forming substances Heat and fat producing substances . . Inorganic matters (ash) 34-68 51-68 13 64 32-43 59-67 7-90 33-80 58-60 7-60 22-019 61-912 16-069 17-944 62-320 19-736 28-175 54-386 17-439 100-00 100-00 100-00 100-000 100-000 lOO-OOO It appears from these analyses that cabbages, and the leaves and flowers of cauliflower, are very rich in flesh-forming sub- stances. Indeed no kind of green food, cultivated On a large scale in the field, contains so much nutritious matter as cabbage. Being much more nutritious, weight for weight, than turnips, and at the same time very succulent, cabbages form a valuable food for milk cows. Cattle are very fond of cabbage, and dairy cows fed upon it and some hay produce much and rich milk ; and the butter made from the latter is free from the disagreeable flavour which it always has when cows are fed upon turnips. Cabbages, for this reason, are a valuable substitute for turnips, and deserve to be more extensively cultivated in England than they are at present. Mangold leaves and turnip tops, it will be observed, also con- 44 VoELCKER on the Chemistry of Food. tain a large amount of nitrogenized matters. Chemically con- sidered, they ought therefore to possess considerable feeding pro- perties ; but experience has shown that their value as articles of food does not range very high. Mangold- wurtzel leaves, more- over, are very apt to scour animals, and ought therefore to be given to them only in moderate quantities. Mangold leaves and turnip tops thus present us with instances which illustrate that the actual value of an article of food cannot always be determined by the same analytical process which in many cases affords good indications of the value of food. Man- gold leaves and turnip tops, it will be seen by a glance at the above tabulated analytical results, contain a very large proportion of inorganic matters, or ash. This ash chiefly consists of alkaline phosphates, which are known to produce a relaxation of the bowels when taken internally, even in moderate quantities. The presence of much phosphate of potash and soda in the leaves of mangolds or turnip tops may thus be the reason why the nutri- tive substances which they contain are not assimilated by the animal organism, and why cattle do not get on well upon such food. 9. Hay and Straw (Clover-Hay and Hay of Artificial Grasses). — The composition of clover-hay, and the hay of arti- ficial grasses, necessarily is regulated by that of the fresh plants which are grown for hay, and which we have seen differ often considerably in composition. Moreover, the composition of hay, and with it its nutritive qualities, depend very much upon the time at which the plants are cut down, on the state of the weather at haymaking time, and the care bestowed upon the haymaking process. For these reasons, it is not practicable to attach a precise nutritive value to clover-hay. Oomposition of Clover-hay and Hay of Artificial Grasses. (According to Professor Way's data.) Flesh- forming Substances. Fatty Matters. Respira- tory Substances. Woody Fibre. Ash. Water. Trifoliumpratense— Red clover . . . Trifolium pratense perenne— Purple 1 clover 5 Trifolium incarnatum— Crimson clover. Trifolium medium — Cow grass . Ditto, second specimen . . . Trifolium procumbens— Hop trefoil. . Trifolium repens— White trefoil . . , Vicia sativa— Common vetch .... Vicia sepium — Bush vetch Onobrychis sativa— Sainfoin .... Medicago sativa — Lucerne Medicago lupulina— Yellow clover . . Plantago lanceolata— Rib grass . . . Poterium sanguisorba — ^Burnet , Achillea millefolium— MiUefoll . . . 18-79 15-98 13-83 20-27 15-64 17-07 15-63 19-68 19-23 15-38 10-63 20-50 11-91 13-96 8-62 3-06 3-41 3-11 2-97 3-98 3-89 3-65 2-55 2-40 2-51 2-30 3-38 3-06 3-34 2-09 37-06 35-35 31-25 30-30 41-38 36-55 33-37 32-87 27-62 38-30 , 33-47 27-76 33-58 39-50 37-88 16-46 21-63 26-99 20-12 15-70 18-88 22-11 22-82 25-87 20- .59 28-51 22-66 27-56 19-89 27-24 7-97 6-96 8-15 9-67 6-64 6-94 8-57 5-42 8-21 6-56 8-42 9-03 7-23 6-64 7-50 16-6 Mean . . . 15-81 1 3-18 34-42 22-47 7-59 16-6 Hay and Straw. 45^ As it may be useful to know what would be the composition of hay produced by the various kinds of clover and artificial a^rasses, the analyses of which are stated above, the preceding table has been compounded. In an air-dry state, clover-hay contains on an average 16 '6 per cent, of moisture. Calculating thus for 16*6 per cent, of moisture in every case, the composition of the hay of the sub- joined clovers and artificial grasses will be as in the table (p. 44). Dr. Anderson states the composition of clover-hay of the second cutting, and grown in the field, as follows : — Moisture 16*84 Flesh-forming substances 13 '52 Non-nitrogenised matters 64*43 Mineral matters (ash) 5*51 100-00 The influence of the period at which clover is cut for hay on the composition of the latter is shown in the following experiments of Stockhard and Hellriegel : — Clover cut on the 4th June, quite young . , , 23rd , , ready for cutting ,, 9th July, beginning to flower , , 29th , , full flower . . ,, 21st August, ripe . . . Stem. Water in Fresh Plant. 82-80 81-72 82-41 78-30 69-40 Hay. Flesh- forming Matters. 13-61 12-72 12-40 9-28 6-75 Ash. 9-71 9-00 6-12 4-63 4-82 Leaves. Water in Fresh Plant. 83-50 §2-68 70-80 65-70 Hay. Flesh- forming Matters. 27-17 27-69 15-83 19-20 18-94 Ash. 9-42- 9-00 10-46 9-58 12-33 It will be observed that the leaves are much more nutritious than the stems, which decrease rapidly in value at the period of maturity. Still more strikingly the deterioration of clover-hay by not cut- ting down the clover at the proper time appears^ in the following experiments by Dr. Wolff, made in 1853 : — Red Clover. Alsike Clover. Beginning to flower, nth June. Full flower, 25th June. Beginning to flower, 23rd June. Full flower, 29th June. Fresh. Hay. Fresh. Hay. Fresh. Hay. Fresh. Hay. Water ...... pr. cent 83-07 1-43 4-24 11-26 pr, cent 16-60 7-04 20-87 55-43 pr. cent 76-41 1-67 8-88 13-04 pr. cent 16-60 5-90 31-37 46-07 pr. cent 86-98 1-12 3-79 8-11 pr. cent 16-60 7-17 24-26 51-91 pr. cent 82-60 1-45 5-11 10-84 p. cent 16*60 Ash . 6-94 Woody fibre Nutritive substances .... 24-47 51-93 4& VoELCKER on the Chemistry of Food. It will be observed that, whilst alsike clover cut on the 23rd of June, and six days later, produced an equally nutritious hay, a fortnight difference in the time of cutting down the red clover was attended with a considerable deterioration of the bay. For whilst the clover cut on the 11th June gave hay containing 20*87 of woody fibre, cut on the 25th, or a fortnight later, it produced 31*37 of indigestible fibre. It is the experience of practical men that the same weight of clover, when made into hay, is not so nutritious as it is in a fresh state. This no doubt is due partly to the changes which clover undergoes in the drying process, but also it is accounted for by the fact that, during the turning and drying in the field, and the subsequent carting of the clover, its more delicate and nutritious smaller leaves are wasted. Unpro- pitious weather, accompanied with frequent heavy rains, still more diminishes the nutritive qualities of the clover-hay, inasmuch as heavy rains wash out a portion of the nutritive juices, and clover which is kept in a wet state for a long time on the field is apt to enter into fermentation, during which a considerable portion of the albuminous compounds is destroyed. Meadow Hay and Aftermath.— Like clover hay, ordinary mea- dow hay and aftermath are liable to considerable variations in composition. The same circumstances which affect the nutritive value of the hay of artificial grasses determine the value of the hay of natural grasses. Taking the mean of 25 analyses of common meadow hay, the composition of the latter may be stated as follows : — Water 14-61 Flesh-forming constituents . . . . 8 • 44 Respiratory and fatty matters . . .. 43*63 Woody fibre 27-16 Mineral matters (ash) 6*16 The composition of the hay produced by the several natural grasses analysed by Professor Way has been stated already under the head of natural grasses. It will be observed that the average composition of hay from 23 different natural grasses agrees well with the average composition of meadow hay, which has just been stated. Well-made hay made of grass, cut rather earlier than is done usually, is richer in flesh-forming matters than ordinary meadow hay. The following analyses by Dr. Wolff may repre- sent the composition of meadow hay of superior quality : — Water 16-94 Flesh-forming matters 10*69 Respiratory and fatty matters .. .. 40-17 Woody fibre 27'16 Mineral matters (ash) 5*04 100-00 On the other hand, the two subjoined analyses by Dr. Anderson may express the composition of inferior meadow hay : — Hay and Straw. 47 Water Flesh-forming matters (nitrogenised matters) Non-nitrogenised substances Mineral matters (ash) Fresh Hay. 16-54 6-16 69-89 7-41 Hay One Year old. 13-13 4-00 77-61 5-26 It is generally believed that aftermath is less nutritious than hay. This may, indeed, be the case, for the aftermath, which is made at a later period of the year, when rainy days are more abundant, often remains a long time in the field before it can be stacked, and thus is deteriorated in value by unpropitious weather. When, however, aftermath is cut not too late in the season, and fair and warm weather allows its being made rapidly into hay, it is quite as valuable as the hay of the first cut. That it may be even more nutritious than the first hay, appears from the following comparative experiments by Dr. Keyser : — Water Flesh-forming matters Respiratoi*y and fatty matters Woody fibre Mineral matters (ash) Hay. 13-38 9-06 42-74 27-15 7-76 100-00 Aftermath. 13-06 10-75 49-74 19-02 7-46 100-00 These results show that the preparation of flesh-forming matters is greater, and that of woody fibre smaller, in aftermath than in the hay of the same meadow, and that consequently the former is the more valuable of the two. It ought to be mentioned that the hay was repeatedly washed by heavy rains, whereas the aftermath was harvested in very favourable weather, in consequence of which the former had a bleached appearance, whilst in the latter the green colour and aromatic taste were preserved ; the aftermath, moreover, was softer and finer than the hay. Straw. — The following table represents the average composition of the straw of cereals : — Wheat- straw. Rye- straw. Barley- straw. Oat- straw. Water Flesh-forming matters Respiratory and fatty matters Woody fibre Mineral matters (ash) .. .. ... 14-23 1-79 31-06 45-45 7-47 14-30 2-29 37-15 43-18 3-08 14-30 1-68 39-98 39-80 4-24 12-06 1-63 37-86 43-60 4-85 100 00 100-00 100-00 100-00 48 VoELCKER on the Chemistry of Food. The differences in the composition of the straw of our cereals are trifling. There is but a small amount of flesh -forming matters and a large amount of indigestible woody fibre in straw, which fully explains its low feeding value. Oat-straw, however, when still somewhat green at the top, is much more nutritious than the sample the composition of which is here stated. Fea and Bean Straw. — The composition of two varieties of bean-straw is stated by Dr. Anderson as follows : — Water Flesh-forming matters Non-nitrogenized substances Mineral matters (ash) 100*00 Common Straw Scotch of Winter- Bean-straw, beans. 19-23 20-90 8-25 6*79 65-85 65*96 6-67 6*35 100-00 The mean of the analyses by Boussingault, Hertwig, and Sprengel, gives for the composition of pea-straw the following results : — Water Flesh-forming matters Respiratory and fatty matters . . Woody fibre Mineral matters (ash) 1 Natural State. Calculated Pry. 12*00 12*55 21*93 47-52 6-00 14*26 24-92 54-00 6-82 100-00 100*00 Bean and pea straw thus are rich in flesh-forming constituents, and differ in this respect materially from the straw of all our cereals, which are far less valuable as feeding materials. Having stated the composition of most articles of food which are employed by the British farmer for feeding or fattening of stock, some considerations may find here an appropriate place, which ought to be well weighed in climating the nutritive value of food and its adaptation to particular purposes. It having been shown by analysis that all the richer kinds of food contain a large amount of flesh-forming constituents, and that no article of food entirely deficient in these principles can support the healthy existence or growth of animals, great importance is necessarily attached to this class of substances in food. We have seen, however, that though essential to the very existence of Practical Considerations. 49 animals, food must contain a number of other constituents in addi- ^ lion to the flesh-forming substances, if it is to meet all the wants of the animal body. It follows from this that the endeavour to determine the relative nutritive value of different articles of food, by merely taking into account the proportion of flesh-forming con- stituents contained in them, must lead to erroneous conclusions, and that consequently the tables of nutrition, which have been constructed by some who have over-estimated the practical im- portance of the nitrogenized compounds in food, have not that practical value which it was believed at one time they possessed. The amount of flesh-forming matters in food does afford useful indications as to its fitness jfor particular purposes ; but it can never become the rule whereby we can measure the comparative nutritive value of the various feeding materials. Food best adapted for producing muscle, when supplied to animals in large quantities, does not sustain their healthy condition, because it is ill suited to feed respiration. Other food, again, is peculiarly well adapted for the laying on of fat, but does not supply in suffix cient quantity the daily waste to which the muscles of animals are exposed, nor does it contain the materials from which the bones are formed, and for these reasons does not meet the wants of the growing nor even the fattening beast. In short, a mixed food, containing both flesh-forming and respiratory substances, as well as fat-producing and saline constituents, and bone-materials, is necessary to preserve the health of an animal, and the nitro- genised or flesh-forming principles alone cannot determine the practical feeding value of food. The total nutritive effect which an article of food is capable of producing thus depends, in ihe first place, on the presence of all these substances, and second, oii a variety of circumstances, to which I beg now to direct the attention of the reader. In estimating the practical value of an article of food, we must take into consideration-— 1. The Age of the Animal. — Young and growing animals require a more concentrated and more readily digestible food than full- grown or store beasts, i. e. food being, comparatively speaking, rich in nitrogenized matters and poor in indigestible woody fibre. The food upon which growing stock is fed not only has to supply the daily waste of muscle, but must also increase the weight of the animals ; and as the process of renewal in young animals moreover proceeds more rapidly than in full-grown stock, the food of the former should contain a larger supply of flesh- forming substances and of bone-materials. Hence the great value of linseed-cake and of linseed-jelly for young stock, and the poor condition of young beasts fed upon too much chaff. The yet tender organs of digestion necessitate a more digestible food 50 VOELCKER on the Chemistry of Food. than that upon which store beasts may be fed with economy, and thus the same food which may be valuable for store beasts will often be found totally unfit for young stock. 2. The various Kinds of Animals. — We know by experience that the best food for horses is by no means the best for cows or sheep, and hence the nutritive value of an article of food will be different in relation to horses from what it is in relation to cattle. The or- ganization of the digestive organs of our domestic animals fully accounts for the different effects which are often produced by the same article of food when given to different kinds of animals. Thus whilst beans are highly nutritious when given to horses, their value for fattening cattle is far less striking ; and whilst cut straw, given by itself, may support store cattle, it cannot sustain for any length of time the life of sheep or horses. The nutritive value of food thus varies with the description of the animals to which it is given. 3. The Natural Disposition or Temper of the Animals. — Whilst some animals, like the Herefordshire cows and shorthorns, are natu- rally good fatteners, Welsh cattle and Kerry cows, to mention only a few instances, never will become very fat, even if they are kept for a long time on abundant supplies of the choicest food. The prac- tical value of food thus is likewise influenced by the natural dis- position of the animal which is kept upon it. 4. The Purposes for which Animals are kept. — The effect which food is capable of producing is also influenced by the purposes for which animals are kept on the farm. The value of food neces- sarily will be a different one, if we speak in relation to working animals, or fattening beasts, or cows kept for dairy purposes. Thus, for instance, the same amount and kind of food which in summer is hardly capable of keeping working horses in good condition, is more than sufficient to render them plump and fat in a short time in winter, when they are retained for days and weeks together in the stable. The nutritive value of food thus is influenced by the work done by the animal. The harder it is kept at work, the greater the waste in muscle, and consequently the richer the food ought to be in flesh-forming matters which is given to working horses or bullocks. Highly nitrogenized food, however, though of great value when given to working animals, does little good, and may even do harm when given in too large a proportion to fattening beasts. Valu- able food for fattening stock is food rich in starch, and still more so, food rich in ready-made fat ; or, to speak generally, food not so well adapted for working animals, because it does not contain a sufficient quantity of muscle material. These few examples will show that the opinion which is enter- tained respecting the nutritive value of food cannot be invariably Digestibility of Food, 51 the same, but is regulated, amongst other circumstances, by the purpose for which the animals are kept oil the farm. The fitness of the same kind of food thus varies with the age, natural disposition, and kind of the animals to which it is given, as well as with the purposes for which they are kept on the farm ; and it is therefore quite impossible to classify the various articles of food in an order which will indicate their relative feeding values in all cases. But supposing the composition of food to be known, and the wants of the animals are well considered, it is still impossible in all cases to estimate beforehand what practical effect a feeding substance will produce, for it may be rich in flesh-forming sub- stances, and contain fat and heat producing compounds, as well as saline and earthy matters ; and yet it may be, comparatively speaking, poor food, inasmuch as its constituents are not assimi- lated by the animal organism. The digestibility of food conse- quently is a point which ought to be well kept in view in esti- mating its nutritive value. Our knowledge of this process of digestion, unfortunately, is so limited, that we cannot speak definitely of all the conditions which regulate the digestibility of food. Still, however, a few circumstances may be pointed out, by way of example, which influence the assimilation of food by the animal system. Amongst other conditions the digestibility of food depends — 1. On the Kinds of Animals. — The same description of food which is assimilated in a great measure by one kind of animal remains almost wholly undigested when given to another. Thus it has bepn proved by direct experiments that cows will extract a great deal of nourishment from cut straw, whilst horses do not possess the power in the same degree of appropriating nourish- ment from cut straw, and sheep likewise do not appear to digest chaff so readily as cattle. 2. On the amount and character of the Woody Fibre contained in Food. — Feeding materials, containing but a small amount of woody fibre, are generally more readily digested than those articles of food which, like straw, principally consist of woody fibre. Hence barley-meal, oats, and grain in general, substances rich in starchy compounds, are so well adapted to the rapid fatten- ing of animals. The condition of the woody fibre further affects the nutritive value of food in no mean degree. Whilst the woody fibre in roots left too long in a growing state on the land, or the fibre of grass and clover left standing until it become dead ripe, is not readily digested, there can be no doubt that the soft fibre of young grass, clover, and roots, is readily assimilated in the animal organism and transformed into starc;h, sugar, and finally E 52 VoELCKER on the Chemistry of Food. into fat. It is for this reason that grain crops, more especially oats, when harvested before the plants have become dead-ripe, produce straw which is greatly more nutritious than the straw of dead-ripe grain crops. In some parts of Scotland the custom prevails to cut the oat when the top of the haulm is still some- what green ; and it is upon straw of that description that store cattle are kept during the winter almost entirely. 3. On the amount of Flesh-forming Substances. — Food too rich in these constituents is not readily digested by cattle, whilst working horses are greatly benefited by food of that description. Thus, bean-meal or peas ought to be given sparingly to cattle, because beans and peas contain a very large amount of flesh- forming substances, which renders them indigestible when given to cattle. 4. On the Bulk of the Food. — The normal functions of the digestive organs not only depend on the composition of the food, but also on the volume. ' The volume or bulk of food contributes to the healthy activity of the digestive organs, by exercising a stimulating effect on the nerves which govern them. Tlie whole organization of ruminating animals necessitates the supply of bulky food to keep the animal in good condition. Experience shows that horses require a less bulky and more concentrated food than cattle ; but if we reverse the case, and feed cattle with too concentrated a food and horses with too bulky a feeding sub- stance, much of the food will remain undigested. 5. On the form in which Food is presented to the Animal. — It sometimes happens that an article of food is said to possess little value, which, properly prepared, may be given to cattle with much advantage. Thus, straw cut into chaff — and, better still, steamed afterwards when mixed with sliced roots — constitutes a very acceptable food for cattle. The bruising of oats, barley, cake, &c., the making of linseed into jelly, the steaming of hay and cooking of food, are illustrations, showing how, by an altera- tion in the form of a feeding material, its digestibility, and with it its nutritive value, becomes enhanced. The benefit of steaming or cooking of food is principally due to this circumstance. It does not add anything new to the food ; it does not call into existence any fresh nutritious matter ; but brings the nourishment present in the food in an unfit condition into a state in which it is more readily assimilated by the animal. Steaming, moreover, reduces the bulk of the food, and masticates, so to speak, the food for the animal. The animal, therefore, is enabled to consume in a given time a larger quantity of food, and so saved to some extent the work of mastication, which, like every movement of the muscle, is attended with a certain loss of the substance of the beast. The quieter and warmer we keep Economical Value of Food. 53 the animal, and the more we facilitate the assimilation of food, the more rapidly it will become fat. By steaming, likewise, the disagreeable smell of musty hay or cake is destroyed, and on the whole, steamed food becomes more palatable. 6. On small Proportions of Substances with which ice may not even be acquainted. — Professor Liebig's researches on the juices of flesh have made us acquainted with a remarkable crystallized substance, to which he has given the name Kreatine. This sub- stance appears to exercise a remarkable "function in the digestion of food. Liebig also showed the presence of phosphate of potash and lactic acid in the juice of flesh, and considers these consti- tuents indispensable for the digestion of meat. He has indeed proved that flesh, from which all juice is perfectly extracted by water, is so indigestible, that even dogs will refuse to eat it. The total amount of the compounds which appear to play so important a function in the digestion of meat is but very small. Now, if the digestibility of flesh is determined in a great measure by small quantities of substances, the importance of which re- mained unnoticed until the master researches of a Liebig on the juices of flesh made us acquainted with the influence the above- mentioned substances play in the process of digestion — is it not likely that vegetable food may contain small quantities of com- pounds which exercise a similar influence ? In conclusion it may be observed, that the economical value of food is further influenced — 1. By prejudicial substances which food may contain. — Thus, for instance, mustard cake cannot be used as a feeding material, notwithstanding its containing a large amount of flesh-forming and fat-producing substances, because in the stomach of the animal fed upon it, it gives rise to the production of the poison- ous irritating essential oil of mustard : or, the refuse cake, pro- duced in the manufacture of castor oil, cannot be used for feeding purposes on account of the drastic effects which the oil, still remaining in the cake, will produce in the animal system. 2. By the mechanical effect the food exercises. — An illustration in point is offered in bran, which, on account of its sharp edges, stimulates the nerves of the digestive canals to such an extent that much of it passes through the system undigested. Other- wise bran ought to be very nutritious, for it contains even more flesh-forming matters, as well as more fatty matter, than wheaten flour. Could not these relaxing effects of bran which, I believe, are principally due to its mechanical condition, be overcome by the cooking or steaming of the bran ? 3. By the physical condition of the food. — It is so self-evident that mouldy, fusty food cannot be so good as it is in a fresh state, that I need not dwell on this point. Every one knows that the 54 VOELCKER on the Chemistry of Food. fresher cake and food in general — (there are some exceptions, as for instance, mangolds, which become better on keeping), — the better it is adapted for feeding-purposes. 4. By the flavour which it imparts to the meat or the milk. — The economical value of an article of food is also regulated by the flavour which it imparts either to the meat or the milk. Aji article of food may be excellent for producing flesh or milk, and yet, on account of the disagreeable flavour which it imparts to either the one or the other, it may not be desirable to employ it as a feeding material. The case of fenugreek seed, to which reference is made above, fully proves this. These remarks, and others which will suggest themselves to practical men, show that the chemical composition of food alone cannot determine its economic value, but that a variety of cir- cumstances have to be taken into account before we can arrive at anything like a correct view of the nutritive value of a feeding material. I^gritwllural Cjj^mistrg. FOUR LECTURES FARMYARD MANURE, ARTIFICIAL MANURES, BARREN AND FERTILE SOILS, OIL-CAKES, &c. By Dr. AUGUSTUS VOELCKER, F.CS., PROFESSOR OF CHEMISTRY IN THE ROYAL AGRICULTURAL COLLEGE, CIRENCESTER, HONORARY MEMBER OF THE HANOVERIAN AGRICULTURAL SOCIETY, AND CONSULTING CHEMIST TO THE BATH AND WEST OF ENGLAND AGRICULTURAL SOCIETY. LONDON: PUBLISHED BY J. KIDGWAY, 169, PICCADILLY. 1857. . CONTENTS. Page Lecture I. — On Farmyard Manure .. .. 3 II.— On the Commercial and Agricultoral Value of Artificial Manures .. .. .. .. ..28 III. — On tue Composition op Fertile and Barren Soils .. 44 IV. — On the Nutritive Value of different Oil-cakes, AND Substitutes for Oil-cakes • .. .. ..61 FOUR LECTURES, &c. 1.— FAEMYAKD MANUKE. Fakmyard manure differs from all artificial manures in several important particulars. I have purposely selected a general title for the lecture inasmuch as the subject is a wide one, and pre- sents to the chemist and the practical man so many points of in- terest that it is a great difficulty to make a proper selection. I do not propose to give a complete lecture on farmyard manure, but to make some observations of interest, which are the result, not of speculation, but of a number of experiments — analytical ones in the laboratory, and practical ones on the farm. I shall first make some remarks on the composition of fresh farmyard manure ; and need not tell any one practically acquainted with the matter, that nothing can be more varying. Manure produced from young growing stock is not so good as that from old or fat- tening animals. Then again that which is produced from under- fed animals is of a very inferior description ; and indeed it is very bad policy to keep animals underfed, for it occasions a waste of food and manure as well. Then the composition of the excre- ments of the domestic animals is different. The excrements of horses, which are fed with a more nitrogenised food, are of a very fertilising character; and perhaps the animal excrements may be placed in the following order : horse- dung and sheep-dung are about equal, then cow-dung, and last pig-dung. But not only the different excrements influence the composition of farmyard manure, but also the quantity of litter employed. Then the way in which the manure is prepared — whether made in boxes which retain everything valuable, or in an open yard ; also in the manner in which it is kept — whether placed on a slope, allowing the best part of the manure to trickle away to the nearest drain, or whether it is kept on level ground, or covered up so as to keep off the rain, must affect the quality of manure. I wish to impress B 2 4 FARMYARD MANURE. upon your mind that it is the complexity of the composition which renders farmyard manure so valuable and indispensable to the farmer. It is a perfect manure, because it contains all the elements necessary for supporting a healthy and vigorous growth of the plant ; and it is a universal one, because it universally produces those effects, and upon a great variety of agricultural products. Another reason why it is so valuable is, that it pro- duces mechanical effects which no artificial manure that I am acquainted with can produce. The important mechanical effects, especially of long dung on clay soils, are not to be underrated. These mechanical effects are attended with highly beneficial results, which cannot be attained by any artificial manure. Composition of fresh Farmyard Manure. — By way of illus- tration, the subjoined Tables, embodying the results of a careful recent examination of farmyard manure, may be given : — Composition of Fresh Farmyard Manure (composed of Uorse, Pig, and Cow Dung). Water 66'17 ♦Soluble organic matter 2*48 Soluble inorganic matter (ash) : — Soluble silica '237 Phosphate of lime -299. Lime -066 .:; Magnesia 'Oil Potash -573 Soda -051 Chloride of Sodium -030 Sulphuric acid '055 Carbonic acid and loss .. -218 1-54 tinsoluble organic matter 25 "76 Insoluble inorganic matter (ash) : — Soluble silica '967 Insoluble silica '561 Oxide of iron, alumina, with phosphates . . . . '596 Containing phosphoric acid ('I'' 8) Equal to bone earth .. .. (-386) Lime 1-120 Magnesia '143 Potash -099 Soda -019 Sulphuric acid '061 Carbonic acid and loss . . . . '484 4-05 100-00 * Containing nitrogen '149 Equal to ammonia '181 t Containing nitrogen '494 Equal to ammonia "599 Whole manure contains ampionia in free state . . '034 ,, in form of salts "088 I FARMYARD MANURE. 5 According to these results, the same manure in a perfectly dry condition will have the following composition : — Detailed Composition of Fresh Farmyard Manure in Dry State. *Soliible organic matter 7'33 Soluble inorganic matter (ash) : — Soluble silica -703 Phosphate of lime . . . . '884 Lime " '185 Magnesia '033 Potash 1-695 Soda -153 Chloride of sodium '089 Sulphuric acid '035 Carbonic acid and loss '772 — 4-55 t Insoluble organic matter 76*15 Insoluble inorganic matter : — Soluble silica 2-865 Insoluble silica .. .... 1-659 Oxide of iron and alumina, with phosphates .; 1-404 Containing phosphoric acid (-528) Equal to bone earth (-822) Lime 3-335 Magnesia -424 Potash .. .. -294 Soda -077 Sulphuric acid '210 Carbonic acid and loss 1-722 11-97 100-00 * Containing nitrogen '44 Equal to ammonia '53 t Containing nitrogen 1*46 Equal to ammonia 1*77 Whole manure contains ammonia in free state .. -10 „ „ in form of salts -26 Fresh farmyard manure being composed of the droppings of horses, cows, and pigs, and the straw used for litter, according to the above determination, in round numbers consists of two-thirds of water, and one-third of dry matters. Since this fresh manure was not more than fourteen days old, and no rain had fallen during the time it had lain in the dung-pit, all the water is due to the urine and the moisture of the droppings and litter. The quantity of straw employed as litter must necessarily affect the general composition of fresh dung, and more especially the amount of moisture which it contains ; but, I believe, we are not far wrong by saying that fresh mixed dung, in the production of which litter has been liberally supplied to the aniinals, when free 6 FAKMYARD MANURE. from rain, consists of one-third of dry matters and two -thirds of moisture. An inspection of the analytical results just mentioned will further bring to view several interesting particulars : — -1. In fresh dung the proportion of soluble organic and mineral substances is small. This circumstance fully explains the slow action of fresh dung when compared with the effect which well- rotten manure is capable of producing. 2. The proportion of insoluble matters, more especially of in- soluble organic matters, in fresh dung, on the contrary, is very large. By far the larger proportion of the insoluble organic matters consists of straw, changed but little in its physical cha- racter and chemical composition. In the sample of manure analysed the amount of insoluble organic matters is ten times as great as that of soluble organic matters, and the proportion of insoluble mineral substances nearly three times as large as the amount of soluble mineral matters. 3. Fresh dung contains a mere trace of ammonia in a volatile state of combination, and but a trifling quantity of ammonia in the form of ammoniacal salts. 4. The total amount of nitrogen contained in the soluble portion of fresh manure likewise is inconsiderable. Most of the nitrogen which, as we shall see by-and-by, is gradually liberated as the fermentation of dung progresses, is contained in the portion of the manure which is insoluble in water. In other words, com- paratively speaking, little nitrogen exists in fresh dung in a state in which it can be assimilated by the growing plants. Thus, in the sample analysed, the readily available amount of nitrogen in 100 lbs. of fresh dung is only *149 of a lb., whilst about four times as much nitrogen, or, in exact numbers, '494 lb., occurs in the insoluble portion of 100 lbs. of fresh dung. 5. A comparison of the composition of the organic soluble matters with the composition of the organic insoluble matters of fresh dung, however, shows that the former are far more valuable than the latter, inasmuch as the soluble organic matters contain a very much larger percentage of nitrogen, and in a state of com- bination in which nitrogen is available to the immediate use of plants. This will appear from the following numbers : — 100 parts of organic soluble matters in fresh dung contain 6*04 of nitrogen. 100 ,, insoluble matters „ „ 1*92 „ In the same weight of each there is thus more than three times as much nitrogen in the soluble organic matters as in the in- soluble organic matters. FARMYARD MANURE. 7 6. With respect to the inorganic or mineral constituents of fresh dung, it will be seen that it contains all those mineral matters which are found in the ashes of all our cultivated plants. 7. Comparing the composition of the soluble inorganic matters with that presented by the insoluble, no essential qualitative dif- ference is perceived between both, for the same constituents which occur in the soluble ash are found also in the insoluble ash. But there exists a striking difference in the quantitative composition of the soluble and the insoluble mineral matters of fresh dung. 8. The principal constituent of the soluble ash of fresh dung, so far as quantity is concerned, is potash ; 100 parts of soluble ash, it will be seen, contain no less than 37*26 parts of real potash, or a quantity which is equivalent to 54*7 of pure car- bonate of potash. The analysis of the soluble portion of ash of fresh dung gave only 14 per cent, of carbonic acid, in- cluding the loss in analysis; and as 3726 of potash take up 17*5 of carbonic acid in becoming carbonate of potash, and moreover much of the soluble lime existed in the water-solution as bicarbonate of lime, it is evident that a considerable quantity of potash is united with silicic acid in the soluble ash. The large percentage of soluble silica confirms this view ; fresh farm- yard manure thus contains much soluble silicate of potash. 9. The large amount of soluble silica, both in the soluble and in the insoluble ash, is deserving notice. In the soluble ash this silica is united principally with potash, and probably also with some soda ; in the insoluble ash it is combined chiefly with lime, or exists in a finely divided state, in which it is readily soluble in dilute caustic potash. 10. The most prominent constituent of the soluble ash of fresh dung is silicate of potash. 11. The most prominent constituent of the insoluble ash is lime. 12. It is particularly worthy of notice that the soluble ash of even perfectly fresh dung contains a very high percentage oi phos- phate of lime. The proportion of phosphate of lime in the soluble portion of ash was in fact found to amount to no less than 19 J per cent, of the whole soluble ash, whilst the percentage of phosphate of lime in the insoluble ash was found to be only 9^. I must confess that I was not prepared to find so large an amount of a compound which is generally considered insoluble in water, and for this reason is not enumerated in the published analyses of farmyard manure amongst the soluble constituents of dung. Repealed experiments, however, executed, with all care to avoid any possible source of error, have shown me that water 8 FARMYARD MANURE. dissolves phosphate of lime or bone-earth much more rapidly and to a much greater extent than it has hitherto been supposed. This observation gains much in interest, if it be remembered that the late Mr. Pusey suggested many years ago a method of rendering bone-dust more efficacious as a manure for root-crops. His plan was to place bone-dust moistened with water and mixed with ashes, sand, or other porous matters in a heap, and to keep this heap moist by pouring occasionally water upon it, or, better still, stale urine or liquid manure. The suggestion has been fol- lowed by many with much success. But few may have known that by adopting Mr. Pusey's plan of reducing bone-dust still further they have been instrumental in generating that combina- tion which gives peculiar value to superphosphate of lime, namely, soluble phosphate of lime. In one of the latest numbers of the * Annalen der Chemie und Pharmacie,' edited by Liebig, Wohler, and Kopp, Pro- fessor Wohler, of the University of Gottingen, makes the im- portant observation that bone-dust moistened with a little water, in the course of a few days yields a considerable quantity of phos- phate of lime to water, and that this solubility rapidly increases with the putrefaction of the gelatine of bones. My analysis of farmyard manure, made a year before the recent notice, which Professor Wohler gave in the * Annalen der Chemie,' respecting the solubility of phosphate of lime in water, may be regarded as a confirmation of Wiihler's direct experiments upon bone-dust, as well as an interesting scientific commentary on Mr. Pusey's practical suggestion of rendering bone-dust more efficacious as a manure for root-crops. 13. The insoluble part of the ash of fresh farmyard manure includes the sand, earth, and other mineral impurities, which mechanically get mixed with the dung. Most of these impuri- ties are mentioned in the ash-analyses as insoluble silicious matter ; another portion is comprehended under oxides of iron and alumina with phosphates ; and a third part, probably a con- siderable portion of the mechanical impurities, is included under lime, for the gravel and soil at Cirencester abounds in carbonate of lime. Due allowance must be made for these mechanical impurities in all considerations respecting farmyard manure, otherwise conclusions will be drawn which the facts of the case do not warrant. 14. Chemically considered Farmyard Manure must le regarded as a perfect and universal Manure. — It is a universal manure, because it contains all the constituents which our cultivated crops require to come to perfection, and is suited for almost every de- scription of agricultural produce. As far as the inorganic fertilising substances arc concerned. FARMYARD MANURE. 9 we find in farmyard manure : potash, soda, lime, magnesia, oxide of iron, silica, phosphoric acid, sulphuric acid, hydrochloric and carbonic acid — in short, all the minerals, not one excepted, that are found in the ashes of agricultural crops. Of organic fertilising substances we find in farmyard manure some which are readily soluble in water and contain a large proportion of nitrogen, and others insoluble in water and con- taining, comparatively speaking, a small proportion of nitrogen. The former readily yield ammonia, the latter principally give rise to the formation of humic acids and similar organic com- pounds. These organic acids constitute the mass of the brown vegetable substance, or rather mixture of substances, which, prac- tically speaking, pass under the name of humus. Farmyard manure is a perfect manure, because experience as well as chemical analysis shows that the fertilising constituents are present in dung in states of combination, which appear to be especially favourable to the luxuriant growth of our crops. Since the number of the various chemical compounds in farm- yard manure is exceedingly great, and many no doubt exist in a different state of combination from that in which they are obtained on analysing farmyard manure, in our present state of knowledge it is impossible artificially to produce a concentrated, universal, and perfect manure, which might entirely supersede home-made dung. I do not refer to the mechanical effect which farmyard manure is capable of producing. This mechanical effect, especially im- portant in reference to heavy clay soils, ought to be duly regarded in estimating the value of common dung, but for the present it may suffice ta draw attention to the fact, that even fresh dung contains a great variety of both organic and inorganic compounds of various degrees of solubility. Thus, for instance, we find in fresh manure volatile and ammoniacal compounds, salts of am- monia, soluble nitrogenized organic matters, and insoluble nitrogenized organic substances, or no less than four different states in which the one element, nitrogen, occurs in fresh manure. In well-rotten dung the same element, nitrogen, pro- bably is found in several other forms. This complexity of com- position — difficult, if not impossible, to imitate by art — is one of the reasons which render farmyard manure a perfect as well as a universal manure. On the Changes which Fresh Farmyard Manure undergoes in Ripening. — The peculiar character of these changes becomes apparent if the composition of fresh dung is compared with that of well rotten dung. I would therefore in the next place direct attention to the subjoined Table, representing the detailed com- position of rotten dung : 10 FAEMYARD MAl^URE. Composition of well-rotten Dung. Water 75-42 ♦Soluble organic matter 3*71 Soluble inorganic matter (ash) : — I Soluble silica -254 Phosphate of lime '.382 Lime '117 Magnesia '(H? Potash -446 Soda -023 Chloride of sodium -037 Sulphuric acid -058 Carbonic acid and loss '106 1-47 flnsoluble organic matter 12*82 Insoluble inorganic matter (ash) : — Soluble silica 1-424 Insoluble silica 1*010 Oxides of iron and alumina, with phosphates *947 Containing phosphoric acid ("274) Equal to bone earth (-573) Lime 1-G67 Magnesia '091 Potash .. .. -045 Soda -038 Sulphuric acid -063 Carbonic acid and loss 1*295 ^'58 100-00 ♦ Containing nitrogen -297 Equal to ammonia -36 f Containing nitrogen -309 Equal to ammonia '375 Whole manure contains ammonia in free state . . '046 „ „ form of salts *057 Dried at 212^ F. the composition of this manure is as follows Composition of the same Manure in dry state. ♦Soluble organic matter .. .. 15*09 Soluble inorganic matter : — Soluble silica 1*035 Phosphate of lime 1*554 Lime -476 Magnesia -193 Potash 1-816 Soda -140 Chloride of sodium '151 Sulphuric acid *235 Carbonic acid and loss *380 5-98 Insoluble organic matter 52*15 Carried forward 73*22 FAEMYARD MANURE. 11 Brought forward .. .. .. 73*22 Insoluble inorganic matter : — Soluble silica 5'79 Insoluble silica 4*11 Oxides of iron and alumina, with phosphates 3*85 Containing phosphoric acid 0*11) Equal to bone earth (2'41) Lime G-78 Magnesia "37 Potash .. -18 Soda -15 Sulphuric acid '29 Carbonic acid and loss 5'26 ^^'"^^ 100-00 * Containing nitrogen 1*21 Equal to ammonia 1*47 t Containing nitrogen 1*26 Equal to ammonia 1*53 Whole manure contains ammonia in free state .. -isg „ „ form of salts '232 The comparison of these analytical results with the numbers obtained in the analysis of the fresh manure exhibits several striking differences, to some of which I beg to direct attention. 1. The well-rotten dung contains nearly 10 per cent, more water than the fresh. The larger percentage of water, it is true, may be purely accidental ; but, considering the tendency of the liquid excrements to sink to the lower part of the manure pit in which the rotten dung accumulates, I believe rotten dung will always be found moister than fresh dung upon which no rain has fallen. 2. Notwithstanding the much larger percentage of moisture in the well-rotten dung, it contains in its natural state, with 76^ per cent, of water, almost as much nitrogen as the fresh dung, with only QQ per cent, of moisture. Supposing both to be equally moist, there would thus be considerably more nitrogen in rotten dung than in an equal weight of fresh. This is clearly observed by comparing the total amount of nitrogen in the perfectly dry fresh and rotten dung. In the former it amounts to 1*90 per cent, of nitrogen, in the latter to 2*47. As far as this most valuable element is concerned, farmyard manure becomes much richer, weight for weight, in becoming changed from fresh into rotten dung. 3. During the fermentation of the dung the proportion of insoluble organic matters greatly diminishes ; thus the dry fresh manure contained 76 per cent, of insoluble organic matters, whilst there were only 52 per cent, in the dry rotten dung. 4. It is especially worthy of observation that, whilst the in- soluble organic matter is much reduced in quantity during the fermentation, the insoluble organic matter which remains behind 12 FARMYARD MANURE. in rotten dung is richer in nitrogen than an equal quantity of in- soluble organic matter from fresh dung. Thus 76 per cent, of insoluble organic matter of fresh dung contain 1'46 per cent., whilst 52 per cent, of it from rotten dung very nearly contain the same quantity, namely, 1*26. Or, — 100 parts of insoluble organic matter ) i .no ^ r -i. from fresh dung contain ^ . . . . . } 1^2 per cent, of mtrogen. 100 i^arts of insoluble organic matter ) <,., from rotten dung contain / "^ " " 5. On the other band, the relative proportion of insoluble inorganic matter increases much during the fermentation of the dung, since dry fresh dung contains about 12 per cent, of insoluble mineral matters, and dry well-rotten dungs 26*8 per cent., or more than double the amount which is found in fresh dung. 6. But perhaps the most striking difference in the compo- sition of fresh and rotten dung is exhibited in the relative pro- portions of soluble organic matter. Well-rotten dung, it will be observed, contains rather more than twice as much soluble organic matters as the fresh ; with this increase the amount of nitrogen present in a soluble state rises from *44 per cent, to 1*21 per cent. 7. Not only does the absolute amount of soluble nitrogenised matters increase during the fermentation of dung, but the soluble organic matters relatively get richer in nitrogen also. Thus, — 100 parts of dry organic soluble matter! g.^o from rotten dung contain / " " 8. Lastly, it will be seen that the proportion of soluble mineral matters in rotten dung is more considerable than in fresh. 9. On the whole, weight for weight, well-rotten farmyard manure is richer in soluble fertilizing constituents than fresh dung, and contains especially more readily available nitrogen, and therefore produces a more immediate and powerful effect on vegetation. Bearing in mind the differences observable in the composition of fresh and rotten dung, we can in a general manner trace the changes which take place in the fermentation of dung. Farm- yard manure, like most organic matters, or mixtures in which the latter enter largely, is subject to the process of spontaneous decomposition, which generally is called fermentation, but more appropriately putrefaction. The nature of this process consists in the gradual alteration of the original organic matters, and in the formation of new chemical compounds. All organic matters, separated from the living organism, are affected by putrefaction, FAEMYAKD MANURE. 13 some more readily, others more slowly. Those organic substances which, like straw, contain but little nitrogen, on exposure to air and moisture at a somewhat elevated temperature decompose spontaneously and slowly, without disengaging any noxious smell. On the other hand, the droppings of animals, and especially their urine, which is rich in nitrogenous compounds, rapidly enter into decomposition, producing disagreeable-smelling gases. In a mixture of nitrogenous substances and organic matters free from nitrogen, the former are always first affected by putrefaction; the putrefying nitrogenised matters then act as a ferment on the other organic substances, which by themselves would resist the process of spontaneous decomposition much longer. Without air, moisture, and a certain amount of heat, organic matters can- not enter into putrefaction. These conditions exist in the drop- pings of cattle and the litter of the stables, hence putrefaction soon affects fresh dung. Like many chemical processes, putre- faction is accompanied with evolution of heat. Air and water exercise an important influence on the manner in which the de- composition of organic matters proceeds. Both are absolutely requisite in order that putrefaction may take place. Perfectly dry organic substances remain unaltered for an indefinite period, as long as they are kept perfectly dry. But too large an amount of water, again, retards the spontaneous decomposition of organic substances, as it excludes the access of air and prevents the ele- vation of temperature, both of which conditions greatly increase the rapidity with which organic matters are decomposed. Al- though air is an essential element in the putrefaction of organic matters the unlimited access is unfavourable to this process of spontaneous decomposition, and is productive of new changes. In farmyard manure the unlimited access of air is prevented by the compact nature of dung -heaps, consequently only a limited quantity of air can find its way into the interior of the mass. During the fermentation of fresh dung, disagreeable smelling gases are given off. These arise principally from the sulphur, and from the phosphorus of the nitrogenized compounds present in dung. A considerable proportion of this sulphur and the phosphorus combine with hydrogen, and form sulphuretted and phosphoretted hydrogen — two extremely nauseous gases, which both escape from fermenting dung-heaps. Another portion of the sulphur and the phosphorus unites with atmospheric oxygen, and in the presence of porous substances becomes changed into sulphuric and phosphoric acid, two non-volatile compounds, which are left behind. We have seen the relative proportion of inorganic matters in well-rotten dung is much greater than in fresh. This increase in mineral matters can have only been produced at the expense 14 FARMYARD MANURE. of organic substances, the quantity of which during the process of fermentation must decrease in a corresponding relative degree. Thus the total amount of organic and inorganic matters in fresh dung, dried at 212° Fahr., is,— ^ Organic matters 83"48 Inorganic matters 16-52 100-00 Whilst in rotten dung there are in 100 — Organic substances 68*24 Mineral substances 31*76 ' 100*00 It is clear therefore that, during the fermentation of dung, much of the organic substances must become changed into com- pounds, which are either readily soluble in water, and easily washed out by heavy rains, or into gaseous products, which are readily volatilized. In point of fact, both volatile gases and readily soluble organic compounds are formed. Amongst the former, carbonic acid and ammonia deserve especial mention ; amongst the latter, soluble humates and ulmates may be named. These ulmates and humates are dark-brown-coloured compounds of humic and ulmic acids, with the alkalies, potash, soda, and ammonia. Ulmic and humic acids in a free state are scarcely soluble in water, and for this reason colour it only a light brown. These organic acids have a very powerful affinity for ammonia, in consequence of which they lay hold of any free ammonia, which is generated in the fermentation of dung, and fix it per- fectly, as long as no other compound is present or produced in fermenting dung, which at an elevated temperature again destroys the union of ammonia with humic, ulmic, and similarly consti- tuted acids. Now, ammonia is generated during the putrefaction of the nitrogenized constituents of dung in large quantities, and would be dissipated into the air much more rapidly than is the case in reality, if there were not formed in the dung itself a group of organic compounds, which act as most excellent fixers of the volatile ammonia. I refer to the humus substances which are gradually produced from the non-nitrogenized constituents of dung. In other words, the straw employed as litter during the putrefaction of dung is to a great extent converted into humic and ulmic acids, which fix to a certain extent the ammonia produced from the more nitrogenous excrementitious matters. The pungent smell of fermenting dung, however, shows that the volatile ammonia cannot be fixed entirely by these means. In the course of this inquiry I shall point out the reason of this, and content myself in this place by saying that the proportion FARMYARD MANURE. 15 of ammonia which passes into the atmosphere from fermenting dung-heaps, and the loss which hereby is occasioned, is much less considerable than it is generally assumed to be. In fer- menting dung-heaps the carbonaceous constituents at first are changed into humus substances, but these are rapidly oxidized by atmospheric oxygen, and partly changed into carbonic acid, a gaseous substance which, in conjunction with oxide of carbon and carburetted hydrogen, is given off abundantly from all putrefying organic matters. I have endeavoured to describe briefly the principal changes which take place in the fermentation of farmyard manure. It has been shown : — 1. That during the fermentation of dung the proportion of both soluble organic and soluble mineral matters rapidly increases. 2. That peculiar organic acids, not existing — at least, not in considerable quantities — are generated, during the ripening of dung from the litter and other non-nitrogenized organic consti- tuents of manure. 3. That these acids (humic, ulmic, and similar acids) form, with potash, soda, and ammonia, dark-coloured, very soluble compounds. Hence the dark colour of the drainings of dung- heaps. 4. That ammonia is produced from the nitrogenous consti- tuents of dung, and that this ammonia is fixed, for the greater part, by the humus substances produced at the same time. 5. That a portion of the sulphur and phosphorus of the excre- mentitious matters of dung is dissipated, in the form of sul- phuretted and phosphoretted hydrogen. 6. That volatile ammoniacal compounds, apparently in incon- siderable quantities, escape into the air. 7. That the proportion of organic substances in fresh dung rapidly decreases during the fermentation of dung, whilst the mineral substances increase in a corresponding degree. 8. That this loss of organic substances is accounted for by the formation of carbonic acid, oxide of carbon, and light-carburetted hydrogen, or marsh- gas. 9. That the proportion of nitrogen is larger in rotten than in fresh dung. The practical result of these changes is, that fresh manure, in ripening, becomes more concentrated, more easily available to plants, and, consequently, more energetic and beneficial in its action. It may be questioned, with much propriety, — Is this apparently desirable result attained without any appreciable loss ? or is it realised at too great an expense ? In other words, Is the fermentation of dung, or is it not, attended with considerable loss of really valuable fertilizing substances ? 16 FARMYARD MANURE. In putting this question we have to bear in mind that the loss in valuable mineral matters, under proper management, practi- cally speaking, can be avoided, since they are non-volatile, and, therefore, must remain incorporated with the dung, if care be taken to prevent their being washed away by heavy falls of rain. We have likewise to bear in mind that, in an agricultural point of view, the carbonaceous, non-nitrogenized manure constituents do not possess a very high intrinsic value; and that we therefore need not trouble ourselves about their diminution, if it can be shown that it is accompanied with other beneficial changes. The only other constituents which can come into consideration are the nitrogenized matters. The question may therefore be thus simplified : Is the fermentation of farmyard manure necessarily attended with any appreciable loss in nitrogen ? Any one may ascertain that fermenting dung gives off am- monia, by holding over a dunghcap, in active fermentation, a moistened reddened litmus-paper. The change of the red colour into blue sufficiently shows that there is an escape of ammonia. However, this experiment does not prove as much as is some- times believed ; for inasmuch as the most minute traces of ammonia produce this change of colour, the escape of this volatile fertilizing matter may be so small that it is practically altogether insignificant. The comparison of fresh with rotten dung, we have seen already, does not decide whether or not fresh farmyard manure sustains a loss in nitrogen in becoming changed into rotten manure. Apparently there is a gain in nitrogen, for we have seen that rotten dung contains more nitrogen than fresh. This gain in nitrogen, however, is explained by the simul- taneous disappearance of, relatively, a much larger quantity of carbonaceous organic matter. Still the accumulation x)f nitrogen in rotten dung is important, and hardly to be expected ; for, since a considerable portion of the nitrogenized organic matters is changed into volatile ammonia during fermentation, a loss, instead of a gain, in nitrogen naturally might be expected. A much greater loss in nitrogen than is actually experienced would, indeed, take place during the fermentation of dung, if this process were not attended with the simultaneous formation within the manure-heap of excellent fixers of ammonia. However, the mere analysis of farmyard manure cannot decide the question which has just been raised, and I therefore at once determined to make the analyses in conjunction with direct weighings of dung in various stages of decomposition. To this end I weighed out carefully two cartloads-full of the same well- mixed sample of fresh farmyard manure, the full analysis of which has been given before. The manure was placed in a heap set against a stone wall, but otherwise exposed to the influ- FARMYARD MANURE. 17 ence of tlie weather. The entire crude loss which this experi- mental heap sustained in the course of time was ascertained by periodical weighings on the weighbridge. Simultaneously with these weighings the manure was submitted to analysis, and thus 1 was enabled not only to determine from time to time the loss in weight which the experimental heap sustained in keeping, but also to ascertain which constituents were affected by this loss, and in which relative proportions. The results of these perio- dical weighings and analyses are incorporated in the following table. Table showing Composition of the Whole Heap : Fresh Farmyard Manure. Expressed in lbs. Weight of manure in lbs 2838 Amount of water in the manure . . Amount of dry matter in the manure Consisting of — ^Soluble organic matter Soluble mineral matter flnsoluble oi'ganic matters Insoluble mineral matter *Containing nitrogen Equal to ammonia fCoutaining nitrogen Equal to ammonia Total amount of nitrogen in manure Equal to ammonia The manure contains ammonia in free state , , , , ammonia in form of) salts, easily decomposed by quicklime) Total amount of organic matters . . Total amount of mineral matters . . When put up. Nov. 3rd, 1854, 1877-9 960-1 70-38 43-71 731-07 114-94 April 30th, 1855. 2026 4*22 5-12 14'01 17-02 18-23 22-14 •96 2-49 801-45 158-15 1336'1 689-9 86-51 57-88 389-74 155-77 969-1 689-9 6-07 7-37 12-07 14-65 18-14 22-02 •15 1-71 476-25 213-65 Aug. 23rd, 1994 1505-3 488*7 58-83 39-16 243-22 147-49 488-7 3*76 4-56 9-38 11-40 Nov. 15th, 1855. 1974 1466-5 507-5 54-04 36-89 214-92 201*65 507*5 3-65 4-36 9-38 11-39 13-14 15-96 •20 •75 302-05 186^65 13 03 15-75 •U •80 268-96 238-54 It will be remarked that in the first experimental period the fermentation of the dung, as might have been expected, pro- ceeded most rapidly, but that, notwithstanding, very little nitrogen was dissipated in the form of volatile ammonia ; and that on the whole the loss which the manure sustained was inconsiderable when compared with the enormous waste to which it was subject in the subsequent warmer and more rainy seasons of the year. Thus we find at the end of April very nearly the same amount of nitrogen which is contained in the fresh ; whereas, at the end C 18 FARMYARD MANURE. of August, 27"9 per cent, of the total amount of nitrogen, or nearly one-third of the nitrogen in the manure, has been wasted in one way or the other. It is worthy of observation that, during a well-regulated fer- mentation of dung, the loss in intrinsically valuable constituents is inconsiderable, and that in such a preparatory process the efficacy of the manure becomes greatly enhanced. For certain purposes fresh dung can never take the place of well-rotten dung. The farmer will, therefore, always be compelled to submit a portion of home-made dung to fermentation, and will find satis- faction in knowing that this process, when well regulated, is not attended with any serious depreciation of the value of the manure. In the foregoing analyses he will find the direct proof that, as long as heavy showers of rain are excluded from manure heaps, or the manure is kept in waterproof pits, the most valuable fer- tilising matters are preserved. But let us now see how matters stand when manure heaps, the component parts of which have become much more soluble than they were originally, are exposed to heavy showers of rain. In the first experimental period little rain fell, and this never in large quantities at a time, whilst in the interval of April and August rain was more abundant, and fell several times in con- tinuous heavy showers. In consequence of this soluble matters in the heap were washed out, and with them a considerable portion of available nitrogen, and the more valuable mineral constituents of dung were wasted. The above analytical data, if I am not mistaken, afford like- wise a proof that even in active fermentation of dung but little nitrogen escapes in the form of volatile ammonia, but that this most valuable of all fertilising materials, along with others of much agricultural importance, is washed out in considerable quantities by the rain which falls on the heaps, and is wasted chiefly in the drainings of the dungheaps. A single fact, it has been truly said, is worth more than a dozen vague speculations. We hear frequently people talk of the loss in ammonia which farmyard manure undergoes on keeping, and this loss is referred by them to the volatilization of the am- monia which is produced in the putrefaction of the nitrogenized constituents of dung. I have, however, already mentioned that simultaneously with the ammonia, ulmic, humic, and other organic acids are generated from the non-nitrogenized consti- tuents of manure, and that these acids possess the power of fixing the ammonia in an excellent manner. If this were not the case, it would be difficult, if not impossible to explain the cir- cumstance that the proportion of soluble nitrogenized matters increased considerably in the manure on keeping for a period of FARMYARD MANURE. W. six months, and that during this period the total amount of nitrogen scarcely suffered any diminution. In April the amount of nitrogen in the soluble matters of the entire heap is 6 '07 lbs., and by the 23rd of August it is reduced to 3*76 lbs. Why, it it may be asked, is it not likely that most of this nitrogen has passed into the air in the form of volatile ammoniacal com- pounds ? In reply to this question, I would answer that a loss taking place in this way would be felt much more sensibly in the period of active fermentation, in which, however, we have seen that scarcely any nitrogen is dissipated. In the August and November analyses, moreover, it will be observed that not only the amount of soluble organic matters, and with it that of the nitrogen, decreases, but that the soluble mineral matters, which in April amount to 57*88 lbs. in the entire heap, became reduced to 39'16 lbs. by the 23rd of August. Now, this decrease in soluble mineral substances can only be ascribed to the rain which fell in this period, and it is plain that the deteriorating influence of heavy showers of rain must equally affect the soluble nitrogenized constituents of dung. It may perhaps appear strange that the total amount of dry matter in the manure is greater in November, 1855, than in August, and likewise that there is a good deal more insoluble mineral matter at the end of the experimental year than at the beginning. In explanation of these apparent inconsistencies, I would observe that the increase in insoluble mineral matters is accounted for in the difficulty of shovelling the manure into the dung-cart without mixing with it each time the weighing is made a certain portion of the soil on which the heap is placed. It must likewise be borne in mind that it is almost next to impos- sible to incorporate mechanical impurities so thoroughly with the dung that differences amounting to 2 or 3 per cent, in the amount of insoluble matters may not occur in the analyses of 2 samples taken from the same heap. In the percentic composition of farmyard manure such differences appear inconsiderable, but when applied to the whole heap they strike us as being great. In short, it is impossible to determine accurately the total amount of insoluble mineral matters in the whole heap. The general deductions, however, which may legitimately be made from the foregoing analyses are not in any perceptible degree affected by this unavoidable source of inaccuracy ; but it is well to remember not to dwell too much on minor differences which perhaps may strike the reader ; some such differences may be due to purely accidental causes. (• 'J 20 FARMYAriD MANUKE. On the Methods of Producing and Keeping Farmyard Manure, With reference to the modes of making manure, allow me to observe at once that I am a strong advocate for the box system, and have every reason to consider manure made in boxes incal- culably superior to that made in open yards, and considerably bet- ter than manure made in stables and covered yards. In the prepa- ration of box manure abundance of litter is employed ; and being cut up, the urine of animals is much more perfectly absorbed than in stables, where much of it passes away. This will ex- plain why box-manure is richer in nitrogen and soluble matters, and consequently much more efficacious than common yard- manure. 1 have heard it stated that the dung made in fattening- boxes remained as fresh after six months as at first ; but this is a mistake. The fact is, the solid and liquid excrements of animals become thoroughly incorporated with the cut straw used as litter, and by the treading of the animals the whole becomes consolidated to an extent that comparatively little air can find access. Still sufficient air comes in contact with the manure, and it undergoes a steady, slow, but uniform fermentation. The dung gradually ripens in the boxes ; and this mode of producing manure pos- sesses the great advantage that, during its stay in the boxes, no ammonia nor any soluble organic and inorganic matters are wasted. In many places there exist, it is true, no facilities of making manure in boxes, and other methods of making manure have to be followed. If the manure cannot be made in boxes, it should at least be produced in covered places, and not be kept longer than it can be helped. The sooner it is carted to the field the better. Manure made in open yards is always of a very inferior de- scription. Generally the animals kept in open yards are store cattle, which are principally fed upon cut straw, and only now and then get a root. It would be a waste to construct a pit with a watertight tank for such manure ; but I cannot help thinking that it is a mistake to expect the straw in open yards much im- proved in manuring qualities by treading it down by underfed store cattle. The man who keeps lean stock may not experience much loss by keeping the manure exposed to the weather in open yards, for the animals get out of the food all that is good, and hardly find enough to support their own frame. We cannot therefore expect much bone materials or nitrogenised matters in the excrements, and it is not likely that the manure will be very efficacious. But to keep dairy-cows or fattening stock in open yards is a bad practice which should never be tolerated. I have always thought that a great loss was experienced by keeping farmyard manure exposed to the rain and wind in open I FAEMYARD MANURE. 21 yards ; but I had no idea of the extent to which manure is diminished in weight and deteriorated in fertilising properties until I had tried a series of very conclusive experiments on this point. With a view of ascertaining the amount of loss farmyard manure sustains, on exposure to the weather in an open yard, I spread 1652 lbs. of fresh dung in an open yard to about the usual thickness, and ascertained from time to time the weight of the manure, and, at the same time, its composition. The results of these weighings and examinations are contained in the following Table:— Table showing Composition of entire mass of Experimental fresh Farmyard Manure, spread. In Natural State. Expressed in lbs. and fractions of lbs. When put up. Nov. 3rd, 1854. April 30th, 1855. Aug. 23rd, 1855. Nov. 15th, 1855. Weight of manure in lbs 1652' 1429* 1012- 950* Amount of water in the manure . . Amount of dry matter Consisting of — ^Soluble organic matter Soluble mineral matter t Insoluble organic matter Insoluble mineral matter 1093* 559* 40-97 25-43 425-67 66-93 1143* 285-5 16-55 14-41 163-79 90-75 709-3 302-7 4-96 6-47 106-81 184-46 622-8 327-2 3-95 5-52 94-45 223-28 559-00 285-50 302-70 327-20 *Containing nitrogen Equal to ammonia f Containing nitrogen Eoual to ammonia 3-28 3-98 6-21 7-54 1-19 1-44 6-51 7-90 •60 •73 3-54 4-29 •32 •39 3-56 4-25 Total amount of nitrogen in manure .. 9-49 11«52 7-70 9-34 4-14 5-02 3-88 4-64 The manure contains ammonia in free state , , , , ammonia in form of ^ salts, easily decomposed by quicklime / Total amount of organic matters . . Total amount of mineral matters . . •55 1-45 466*64 92-36 •14 •62 180' 34 105-16 •13 •55 111-77 190-93 •0055 •28 98-40 •228-80 This Table requires an explanatory notice. It will be ob- served that the amount of insoluble mineral matters in the manure increases greatly in every succeeding experimental period. Es- pecially it is great in November, 1855. This increase is due entirely to accidental admixtures of earthy matters, which could not be excluded without losing some of the manure. It was found, namely, impossible to collect the manure properly without mixing with it some of the soil over which it was spread. On the 23rd of August, 1855, the manure had shrunk to a very small bulk, and on the 15th of November, 1855, the greater portion of the 22 FARMYARD MANURE. manure appeared to have gone either into the air or to have been washed into the soil. It was necessary therefore to scrape the soil as close as possible in order not to lose any of the manure ; and it is due to this circumstance that at the conclusion of the experiment a very much larger proportion of insoluble mineral substances was found than in the perfectly fresh manure. 1 may mention, however, that the whole mass of the spread manure has been most carefully mixed before a sample was taken for ana- lysis. The earthy matters I have every reason to believe were intimately mixed with the manure ; and since the composition of the entire mass has been calculated from the data already fur- nished, the general deductions which may be derived from my experiments are not affected by this circumstance. In speaking of the loss which this manure sustained in keeping, I will select the more important fertilising constituents for illustration, and in reference to them beg to make the following observa- tions : — 1. The weight of the whole manure, when spread out in an enclosed yard, amounted to 1652 lbs. In this quantity were present 40*97, or nearly 41 lbs. of soluble organic matters. After the lapse of six months only 16^ lbs. were left in the manure ; in nine months barely 5 lbs., and after twelve months merely 4 lbs. Thus only about 1-lOth part of the original quantity of soluble organic matters was left over by keeping fresh farmyard manure spread out in an open yard. 2. The nitrogen contained in the 41 lbs. of soluble organic matters amounted to 328 lbs. After six months only 1*19 lbs. of nitrogen, in the state of soluble compounds, was left ; after nine months little more than J lb., and after twelve months only -^ of a lb. In other words, the nitrogen in the state of soluble compounds has disappeared almost entirely in the course of a year. 3. In an equally considerable degree the soluble mineral matters were dissipated in the manure. Originally the manure contained 25*43 lbs. of soluble mineral matters. After six months this quantity became reduced to 14*41 lbs ; after nine months to 6*47 lbs., and after a lapse of twelve months to 5*52 lbs. On the whole the manure thus lost 78*2 per cent, of the ori- ginal quantity of soluble mineral matters. 4. Still more striking is the loss in insoluble organic matters. In the fresh manure were present 425 67 lbs. of insoluble organic substances. In the course of six months these became reduced to 163*79 lbs. ; a further exposure of rather more than three months to the weather reduced this quantity to 106*81 lbs., and after twelve months merely 94*45 lbs. were left over. The manure FARMYAED MANURE. 23 lost thus no less than 77*7 per cent, of the original quantity of insoluble organic matters. 5. If we look to the total amount of nitrogen, we shall find that the original proportion of nitrogen in the manure, amounting to 9*49 lbs., was reduced in the course of six months to 7*70 lbs., after nine months to 4*14 lbs., and after twelve months to 3-88 lbs. At the conclusion of the experiment more than half the quan- tity, or, in exact numbers, 59'1 per cent, of the nitrogen con- tained in the fresh manure, was wasted. 6. If we replace, in the analysis made on the 15th November, 1855, the number which expresses the amount of insoluble mineral matters by the number 66*93, expressing the proportion of insoluble mineral matters which the manure contained at the commencement of the experiment, and which it would have also contained had no earthy matters been mixed up with the manure, and add to it the other constituents, we obtain for the corrected composition of the whole manure in November, 1855, the fol- lowing numbers, which for comparison's sake are contrasted with the analysis of the fresh manure of November, 1854 : — At conclusion of When put up, experiment, Nov. 3, 1854. Nov. 15, 1855. lbs. lbs. Weight of the manure 1652 950 Amount of water in the manure 1093 622*8 „ dry substances 559 170*85 Consisting of : — Soluble organic matters 40*97 3*95 * Soluble mineral matters 25*43 5*52 flnsoluble organic matters . . 425*67 94*45 Insoluble mineral matters 66*93 66*93 559*00 170*85 ♦ Containing nitrogen 3*28 '32 Equal to ammonia 3*98 '39 t Containing nitrogen .. .. 6*21 3'56 Equal to ammonia 7*54 4'25 Total amount of nitrogen in manure 9*49 3*88 Equal to ammonia 11*52 4*64 The whole manure contained : — Ammonia in free state '55 '0055 Ammonia in form of salts readily decomposed by quicklime 1*45 '28 Total amount of organic matters 466*64 98*40 ,, mineral matters 92*36 72*45 It will hence appear from these results that the experiment was begun with 559 lbs. of dry manure ; after the lapse of twelve months, only 170*85 lbs. were left behind. Kept for this length of time spread in an open yard, the manure thus lost no less than 24 FARMYARD MANURE. 69*8 per cent, in fertilising matters ; or, in round numbers, two- thirds of the manure were wasted, and only one-third was lejt behind. This fact teaches a most important lesson, and speaks for itself so forcibly that any further comment appears to me useless. I have already observed that there is no advantage in keeping manure for too long a period before carting it on the fields, and again beg to urge you to adopt this last-named plan in preference to setting up a manure-heap in a corner of the field and exposing it to the deteriorating influence of rain. You need not be afraid that it will lose any of its essential fertilizing constituents by spreading it out, even if you cannot plough in the manure for a long time to come. By spreading out the manure, the fermenta- tion is stopped immediately, and no ammonia can possibly escape into the air. The rain which falls on the manure will wash its valuable constituents into the soil, the very place where they are wanted to be. By spreading the manure over the land and allowing it to be washed in gradually by the falling rain, it becomes much more uniformly incorporated with the soil than by any other method, and this unquestionably is a great advantage ; in proof of which I beg to remind you of the superior effect of superphosphate when sown with the liquid manure drill, or guano mixed with salt, sand, or anything which tends to secure a more uniform dis- tribution of this fertilizer. Some farmers are afraid that heavy rain might wash into the subsoil the best fertilizing constituents of manure, especially when it is carted on the land in autumn ; but this fear is unfounded, for the beautiful researches of Professor Way have shown that most soils of average quality possess the power of absorbing manuring matters and retaining them so firmly, that they cannot be sensibly removed by the heaviest showers or long-continued rain. The only exception to this general absorbing property of soils we find in very light sandy soils. On such soils the manure should be used just before the crop is sown which is intended to be cultivated. I am aware, however, that the manure cannot always be carted at once on the land, and for the root-crops has to be kept until it is thoroughly decomposed. Where the manure cannot be made in boxes, it is very desirable that it should be kept in covered pits. However there is no rule without exception, for where litter is abundant, as in the neighbourhood of Cirencester, all the rain which falls in the year is required to make the straw into manure, and it would entail additional cost to place a dung-pit under cover. Under such circumstances, I think the expense for erecting a roof over a dung-pit may be avoided with propriety. With reference to the time of applying farmyard manure, I would observe that much depends on the kind of land which is FARMYARD MANURE. 20 to be manured. On the whole, I think autumn manuring greatly preferable to spring manurino^, even in the case of moderately strong land. On stiff clay soils farmyard manure should always be used in autumn, and, if possible, be ploughed in before the frost sets in. By this means the full advantage of manure is secured, for, in addition to the chemical effects which manure is capable of producing, it will exercise upon stiff clays a most bene- ficial mechanical effect by keeping the land more porous and open. On the other hand it is not desirable, for obvious reasons, to apply manure in autumn to very light sandy land. As in the beginning of this lecture 1 have treated many inte- resting points with reference to farmyard manure in a very cursory manner, I beg to refer those who wish to study more fully the chemistry of farmyard manure to a paper of mine, published in the ' Journal of the Royal Agricultural Society of England,* July, 1856. Before concluding, however, I may be permitted to state the following general conclusions, to which a series of similar experiments to those referred to in this lecture have led me : — Conclusions. 1. Perfectly fresh farmyard manure contains but a small pro- portion of free ammonia. 2. The nitrogen in fresh dung exists principally in the state of insoluble nitrogenized matters. 3. The soluble organic and mineral constituents of dung are much more valuable fertilizers than the insoluble. Particular care, therefore, should be bestowed upon the preservation of the liquid excrements of animals, and for the same reason the manure should be kept in perfectly waterproof pits, of sufficient capacity to render the setting up of dungheaps in the corner of fields, as much as possible, unnecessary. 4. Farmyard manure, even in quite a fresh state, contains phos- phate of lime, which is much more soluble than has hitherto been suspected. 5. The urine of the horse, cow, and pig, does not contain any appreciable quantity of phosphate of lime, whilst the drainings of dungheaps contain considerable quantities of this valuable fer- tilizer. The drainings of dungheaps, partly for this reason, are more valuable than the urine of our domestic animals, and there- fore ought to be prevented by all available means from running to waste. 6. The most effectual means of preventing loss in fertilizing matters is to cart the manure directly on the field whenever cir- cumstances allow this to be done. 7. On all soils with a moderate proportion of clay no fear need to be entertained of valuable fertilizing substances becoming wasted if the manure cannot be ploughed in at once. Fresh, and even 20 FARMYAED MANURE. well-rotten dung, contains very little free ammonia ; and since active fermentation, and with it the further evolution of free ammonia, is stopped by spreading out the manure on the field, valuable volatile manuring matters cannot escape into the air by adopting this plan. As all soils with a moderate proportion of clay possess in a remarkable degree the power of absorbing and retaining manuring matters, none of the saline and soluble organic constituents are wasted even by a heavy fall of rain. It may, indeed, be ques- tioned whether it is more advisable to plough-in the manure at once, or to let it lie for some time on the surface, and to give the rain full opportunity to wash it into the soil. It appears to me a matter of the greatest importance to regu- late the application of manure to our fields so that its consti- tuents may become properly diluted and uniformly distributed amongst a large mass of soil. By ploughing in the manure at once, it appears to me this desirable end cannot be reached so perfectly as by allowing the rain to wash in gradually the manure evenly spread on the surface of the field. By adopting such a course, in case practical experience should confirm my theoretical reasoning, the objection could no longer be maintained that the land is not ready for carting manure upon it. I am much inclined to recommend as a general rule : cart the manure on the field, spread it at once, and wait for a favourable opportunity to plough it in. In the case of clay soils, I have no hesitation to say the manure may be spread even six months before it is ploughed in, without losing any appreciable quantity of ma- nuring matters. I am perfectly aware that, on stiff clay-land, farmyard manure, more especially long dung, when ploughed in before the frost sets in, exercises a most beneficial action by keep- ing the soil loose and admitting the free access of frost, which pulverizes the land, and would therefore by no means recommend to leave the manure spread on the surface without ploughing it in. All I wish to enforce is, that when no other choice is left but either to set up the manure in a heap in a corner of the field, or to spread it on the field, without ploughing it in directly, to adopt the latter plan. In the case of very light sandy soils it may perhaps not be advisable to spread out the manure a long time before it is ploughed in, since such soils do not possess the power of retaining manuring matters in any marked degree. On light sandy soils I would suggest to manure with well- fermented dung shortly before the crop intended to be grown is sown. 8. Well-rotten dung contains likewise little free ammonia, but a very much larger proportion of soluble organic and saline mineral matters than fresh manure. 9. Rotten dung is richer in nitrogen than fresh. 10. Weight for weight, rotten dung is more valuable than fresh. FARMYARD MANURE. !27 11. In the fermentation of dung a very considerable proportion of the organic matters in fresh manure is dissipated into the air in the form of carbonic acid and other gases. 12. Properly regulated, however, the fermentation of dung is not attended with any great loss of nitrogen nor of saline mineral matters. 13. During the fermentation of dung, ulmic, humic, and other organic acids are formed, as well as gypsum, which fix the am- monia generated in the decomposition of the nitrogenized con- stituents of dung. 14. During the fermentation of dung the phosphate of lime which it contains is rendered more soluble than in fresh manure. 15. In the interior and heated portions of manure-heaps am- monia is given off; but, on passing into the external and cold layers of dungheaps, the free ammonia is retained in the heap. 16. Ammonia is not given off from the surface of well-com- pressed dungheaps, but on turning manure-heaps it is wasted in appreciable quantities. Dungheaps for this reason should not be turned more frequently than absolutely necessary. 17. No advantage appears to result from carrying on the fer- mentation of dung too far, but every disadvantage. 18. Farmyard manure becomes deteriorated in value when kept in heaps exposed to the weather — the more the longer it is kept. 19. The loss in manuring matters, which is incurred in keeping manure-heaps exposed to the weather, is not so much due to the volatilization of ammonia as to the removal of ammoniacal salts, soluble nitrogenized organic matters, and valuable mineral mat- ters, by the rain which falls in the period during which the manure is kept. 20. If rain is excluded from dungheaps, or little rain falls at a time, the loss in ammonia is trifling, and no saline matters of course are removed ; but if much rain falls, especially if it descends in heavy showers upon the dungheap, a serious loss in ammonia, soluble organic matters, phosphate of lime, and salts of potash is incurred, and the manure becomes rapidly deterio- rated in value, whilst at the same time it is diminished in weight. 21. Well-rotten dung is more readily affected by the deterio- rating influence of rain than fresh manure. 22. Practically speaking, all the essentially valuable manuring constituents are preserved by keeping farmyard manure under cover. 23. If the animals have been supplied with plenty of litter, fresh dung contains an insufficient quantity of water to induce an active fermentation. In this case fresh dung cannot be properly fermented under cover, except water or liquid manure is pumped over the heap from time to time. Where much straw is used in the manufacture of dung, and no 28 THE COMMERCIAL AND AGRICULTURAL provision is made to supply the manure in the pit at any time with the requisite amount of moisture, it may not be advisable to put up a roof over the dung- pit. On the other hand, on farms where there is deficiency of straw, so that the moisture of the excrements of our domestic animals is barely absorbed by the litter, the advantage of erecting a roof over the dung-pit will be found very great. 24. The worst method of making manure is to produce it by animals kept in open yards, since a large proportion of valuable fertilizing matters is wasted in a short time ; and after a lapse of twelve months at least two-thirds of the substance of the manure is wasted, and only one-third, inferior in quality to an equal weight of fresh dung, is left behind. 25. The most rational plan of keeping manure in heaps ap- pears to me that adopted by Mr. Lawrence, of Cirencester, and described by him at length in Morton's ' Cyclopjcdia of Agri- culture/ under the head of ' Manure/ 2.— THE COMMERCIAL AND AGRICULTURAL VALUE • OF ARTIFICIAL IMANURES. [Delivered at Barnstaple, January, 1857.] Any one who has seen the astonishing effects which guano pro- duces when applied to corn crops, or superphosphate when applied to root crops, can doubt no longer the very great import- ance which the introduction of artificial manures has acquired with respect to practical agriculture. It is from the introduction of artificial manures that we have to look forward for still greater success in agricultural improvements. When artificial manures were first brought under the notice of farmers they were offered for sale in a very crude and inefficient state ; and it is really marvellous to see the vast improvements which have taken place in their manufacture. Year after year are improvements introduced by intelligent manufacturers possessed of sufficient capital to carry out the suggestions of scientific chemists in an efficient manner, and scarcely has one improvement met with practical success before another is brought under the notice of practical farmers. It is really surprising that, notwithstand- ing the great improvements which intelligent manufacturers of artificial manures have introduced into their manures, there should be manures of a very low standard still offered in the market, and purchased by practical farmers. I have been thinking a good deal about the causes which would account for the curious anomaly, that, while there are in the manure market artificial manures of the highest degree of fertility — manures VALUE OF ARTIFICIAL MANURES. 29 which are really worth the money which is asked for them, there are others, scarcely worthy the name of artificial manures, offered for sale and finding ready purchasers ; and I have come to the conclusion that, in the first instance, the proper use to which artificial manures should be applied by farmers is not so well understood as it is desirable it should be ; and, secondly, that there are in the case of the small farmer, peculiar circum- stances which account for the anomaly that the best manures often do not find so ready a sale as manures altogether of an inferior character. With respect to the first point I would observe that it is quite an erroneous view to think that an artificial manure should answer the same purposes for which common farmyard manure is usually applied. Farmyard manure is a perfect and universal manure, and, if you have plenty of it, it would be foolish buying artificial manures ; but the question is, can you always make farmyard manure with a profit ? can you always feed animals with a profit so as to produce sufficient home-made manure to answer your purpose ? Supposing you can feed with profit only a limited quantity of stock, would you not make that quantity of home-made manure which you produce by the judicious selection of artificial manures go once or twice as far as yoii would without the use of artificial manures ? I answer that question by a decided " Yes." I think the judicious selection of artificial manure will not supersede farmyard manure, but will enable the intelligent agriculturist to make one ton go twice as far as it would without the simultaneous use of artificial manures. Some manufacturers recommend as a peculiar feature of their articles which they offer for sale, that they are equal to the best home-made manure ; that they are, in fact, universal manures, answering to every description of crops ; but I think the very recommendation is a condemnation of their manures : for it must not be the aim of the manure manufacturer to produce a manure similar in character to farmyard manure, but rather to produce manure not partaking of the characters peculiar to farmyard manure. You must well remember that farmyard manure exercises a mechanical as well as a chemical effect upon the soil and the crops which are intended to be raised. The mechanical effect produced by farmyard manure tends to lighten the soil, and admit freely air and atmospheric food for plants, and indirectly to offer for the plants the food of the soil, which is present in it in an insoluble state, and which, by the introduction of farm- yard manure, is rendered soluble. These mechanical effects, which are intimately connected with the chemical effects which farmyard manure produces in soils, cannot well be imitated by any artificial manure. It is irrational to expect artificial manures to produce these mechanical effects ; you ought rather to look to 30 THE COMMERCIAL AND AGRICULTURAL the direct food which artificial manure supplies to plants, and which is supplied by home-made manure to only an inconsi- derable extent. Composition of fresh and well-rotten Farm- Yard Manure (composed of Horse, Pig, and Cow Dung). Fresh. Well-Rotten. In Natural State. . Dry. In Natural State. Dry. Water .. - .. .. 66-17 75-42 Soluble Organic Matter . . . . 2-48 7^33 3-71 15^09 Soluble Inorganic Matter (Ash) :— Soluble Silica •237 •703 •254 1-035 Phosphate of Lime •299 •884 •382 1-554 Lime •006 •185 -117 •476 Magnesia . . . . •Oil •033 •047 •193 Potash •573 1^695 •446 1-816 Soda •051 •153 •023 •140 Chloride of Sodium •030 •089 •037 •151 Sulphuric Acid •055 •035 •058 -235 Carbonic Acid and) Loss / •218 •773 •106 •380 , i'5i 1-55 "i-Ofi Insoluble Organic Matter . . . . 25^76 76^15 12-82 .52-15 Insoluble Inorganic Matter (Ash) :— Soluble Silica •964 2 •865 1-424 •670 Insoluble Silica . . •561 1-659 I-OIO 4-11 Oxide of Iron Alu-l mina Phosphates . . | •596 1-404 •947 3.85 Containing Phos-) phoric Acid . . . . j (•178) (•528) (-274) (1-11) Equal to Bone Earth (•386) (•822) (-573) (2-41) Lime 1-120 3-335 1-667 6-78 Magnesia •143 •424 •091 •37 Potash •099 •294 •045 •18 Soda •019 •677 •038 -15 Sulphuric Acid •061 •210 -063 •29 Carbonic Acid and| Loss / •484 1^722 1-295 5-2G 4-05 1 1 • n~ P.- 'iR 26 -78 100-00 100^00 100^00 100-00 Containing Nitrogen Equal to Ammonia •149 •44 -297 1-21 •181 •53 -36 1^47 Containing Nitrogen •494 1-46 •309 1^26 Equal to Ammonia •599 1-77 •375 1-53 Whole Manure, con-| taining Ammonia !> in free state . . . . ) 0-34 -10 •046 •189 „ in form of Salt 0-88 •26 •057 •052 VALUE OF ARTIFICIAL MANURES. 31 If you look at the composition of farmyard manure, you will observe entering into it, a large amount of substances which are present in the soil in abundance, or which — in the form of straw or litter — can be easily incorporated with the soil, and which are cheap and readily procurable in the market. Now these cheap materials — amongst which I would mention lime, magnesia, silica (which is but another name for sand), oxide of iron, alumina, and a few other substances — are abundantly in the soil. When supplied in the manure, they do not produce any striking effect, but there are other constituents entering into the composition of farmyard manure, which, when supplied to the soil, produce the most striking effects. The amount of nitrogen in fresh farmyard manure, or in rotten dung, is exceedingly small ; but, notwith- standing this, it exercises a most remarkable effect upon wheat, barley, oats, and grass crops. All substances containing nitrogen may be regarded as special manures for cereals and grass crops. Their especial function is to promote the luxurious growth of cereals ; and hence you need not feel astonished to see a remarkable effect following the use of guano, for this is a manure rich in nitrogen, and, in conse- quence of the large amount of ammonia which it contains, pro- duces an extremely beneficial effect on the wheat crop. Another constituent present in farmyard manure, only in small quantities, is phosphate of lime — the principal constituent of bones. Bones, as most of you know, consist, as far as their bulk is concerned, principally of phosphate of lime. Now phosphate is extremely useful for root crops. It is required by all agricultural produce 5 but experience has shown that it is most beneficially applied to root crops. My time will not permit me to assign the reasons why phosphate of lime, when supplied to the soil in a proper state, is especially useful to root crops; but I appeal to the general experience of practical farmers, and content myself by saying, rather dogmatically, that phosphate of lime is a special manure for root crops. At all events, it is one of the most important fertilising materials which is found in farmyard manure ; but you will observe that the proportion of bone material, or phosphate of lime, in farmyard manure is but small. There is a class of substances of the name of potash and soda, two substances comprised under the general name of alkalis. These alkalis — potash and soda — are largely required by all agricultural plants. They are found in the ashes of all agricul- tural produce, and are absolutely necessary for their existence. Now the great value of artificial manures depends just on this, that they concentrate these important fertilising materials — important because all soils contain them only in small quantities, and all agricultural produce requires them in larger quantities 32 THE COMMERCIAL AND AGRICULTURAL than any of the other constituents which are found in farmyard manure. The great value of artificial manures depends upon the circumstance that they present these important constituents in a concentrated state. Perhaps some of you may say, " It's all very well for you to tell us this ; and to lecture to practical men about phosphate and ammonia, but how far does your theoretical reasoning agree with the experience of farmers ?" I would refer you in answer to this, to the acknowledged advantages which the use of guano and superphosphate produces ; and any one who has seen the striking results of these two descriptions of manure will see at once that their value does not depend upon anything mysterious, but upon real chemical substances. It must always be our aim to be guided by practical experience, and to explain matters of fact which are the results, not only of the limited experience of a farmer in one district, but also of the general experience of farmers throughout the country. I would impress upon my audience the important fact tliat the value of artificial manures cannot be simply ascertained by practical experiments, unless these experiments are various in their character, and extend over a long series of years. An analysis of manure will give you useful hints as to the money which you ought to pay for it, but it does not tell you which is the best manure which, under existing circumstances, ought to be used ; and it is not the oflfice of the scientific chemist or the manure dealer to recom- mend to his clients particular manures. The fact of the case is that the farmer must use his own judgment ; at the same time I would remind you that artificial manures are not intended to save labour. Those who think that good crops can be secured by merely using guano, or superphosphate, or nitrate of soda, or any other artificial manure, without adopting other means, will fmd them- selves grievously disappointed. The fact is, the use of artificial manures requires superior intelligence, I might almost say a special training, which can hardly be expected from men who all their life have been accustomed to follow farming as a livelihood. I would say to all those who are not in a position to use artificial manures with advantage, Better follow your own approved system of farming, without using artificial manures at all, than simply depend upon the use of artificial manures for success. No success will follow unless you introduce into your farming practice improvements of another character. Tlie best manures are frequently condemned for want of not using mecha- nical means of cultivation, which so greatly improve the condition of the soil. I cannot too strongly impress upon your minds the fact, that it is not merely by using artificial manures that profit- able results are obtained in farming matters. It is of the greatest VALUE OF ARTIFICIAL MANURES. 33 importance that you look first to the mechanical improvement of the soil. I have seen in many cases superphosphate entirely fail, for want of a proper pulverisation of the soil. A very striking case was very recently brought under my notice. On the farm attached to the Agricultural College of Cirencester, with which I am connected, I have lately made some experience with dif- ferent manuring matters. On one portion of the soil I used superphosphate : the result was that on this portion I did not get a single hundred vveight more produce than on another portion in close proximity where no superphosphate was used at all. Fortu- nately I tried the same experiment on another portion of the farm, and got a very large result. Now, if I had been content with making only one experiment, to what conclusion should I have arrived ? To the following: that on clay soils — for it was a clay soil on which I tried the experiment — superphosphate was of no use ; and that it was the worst manure I could use, for it hardly gave me any increase. But I should have drawn a wrong conclusion, and you will observe how difficult it is to form a satisfactory conclusion from a single experiment : for, having tried the same experiment on a similar soil, — but upon a soil which was taken in hand for several years before the experi- ment was tried, and which, when the manure was applied, was in a high state of mechanical subdivision — I obtained three times as much as upon the portion of land where nothing was applied. You will observe, then, how the mechanical condition of the soil influences the efficacy of artificial manures. Some manufacturers of artificial manures are so well aware of the importance of introducing into farming improved agricultural implements, that they sell those implements without any profit, for they know that they can only then expect a large sale of their manures, when the farmer does the best on his part, and that good manures have no chance of any success, if no care is taken to bring the soil in such a mechanical condition that the artificial manures can exercise any beneficial effect. In the next place, allow me to observe, that the chemical com- position of the land greatly influences the efficacy of manure. There are some soils in which phosphatic manures — manures containing bone material, or phosphate of lime — have no effect. Some soils resting on the greensand formation contain sufficient phosphate of lime to meet all the requirements of the growing crops ; hence you cannot feel surprised that bones or superphos- phate produce no effect upon such soils. The fact is, the soil already contains more than sufficient phosphate of lime to meet all the requirements of the plant ; and hence it is that dealers in superphosphate, containing frequently a very small proportion of of bones, can dispose of their inferior description of superphos- 34 THE COMMERCIAL AND AGRICULTURAL phate in localities where bone materials exist in large quantities in the soil ; in other words, when they can carry on their trade in a very rich part of the country, they will meet with quite as much success as manufacturers selling superphosphate containing a high percentage of phosphate. The first questions for the farmer to ask himself are, what will answer my purpose best? what will give me a good crop ? and what manure gives me the best return ? and, having settled these questions, I think he should then ask, what ought I to pay for the manure which has answered my purpose ? I beg to direct your attention, in the next place, to a few more conditions which influence the efficacy of manure. If you use a top dressing of guano, or nitrate of soda, too late in the season, upon wheat or oats, it hardly produces any effect. I would not use a top dress- ing for wheat later than February. On clay soils it may be advisa- ble to use it in autumn. When used late in spring, guano, nitrate of soda, and similar manures, do not produce any great effect; while, when the same manures are used at the proper time, they produce a most beneficial result. The time of application then greatly influences the efficacy of manure ; but not only the time, but also the mode in which the manure is applied. If you use a concentrated manure like guano, in an imperfectly powdered state — perhaps with all the hard lumps in it you find in the bags which you get from the manure merchant — it does not produce that effect which is realised by crushing and sifting it, and perhaps mixing it with salt or sand. You have no doubt seen it recommended to mix salt with guano. Some persons think salt has the effect of "fixing" the ammonia, but the " fixing'* of ammonia by salt is all nonsense, for the simple reason that guano contains scarcely any free ammonia. The result of a number of experiments gave me as the amount of carbonate of ammonia in guano hardly three quarters per cent., a very small quantity indeed. Allow me to suggest to you to mix guano with oil of vitriol. You will find that the peculiar smell is by no means destroyed by sulphuric acid, which would be the case if it were due to ammonia. People run wild with the idea that every- thing which smells is ammonia. They talk of ammonia and carbonic acid, and then think they have done a great service by introducing chemistry to the notice of the practical farmers ; but such men do a great deal towards bringing that science into dis- repute. Well, now, why does guano act so well when mixed with salt? Chiefly, I believe, because you cannot mix it without breaking down the hard lumps, and thus distribute it more equally upon the land, and everything in farming depends upon the equal distribution of manuring substances. I would say, mix the guano with earth (if dry), burnt clay, sand, or salt ; but this is a VALUE OF ARTIFICIAL MANURES. 35 dangerous thing to say, for some people have taken a strong fancy for salt, and if they are told to mix guano with sand, it will sound far too homely. They are much more likely to follow your advice if you tell them to mix it with salt. Therefore it is some- times advisable not to say the exact thing : a little mystery might be, perhaps, under existing circumstances the best ; but, for my own part, I have a great horror for anything like humbugging the practical man. It is not by blind experiments that any great success can well be realised in farming matters. Nor is it by mere theoretical speculations that agriculture will be greatly advanced ; but it is by the joint labours of the practical man in the field, and the researches of the man of science, that great and important results may be confidently expected. In the next place I would observe that there are circumstances over which the farmers frequently have no control which greatly influence the efficacy of manures. For instance, you cannot always make certain of good seasons ; and in a bad season the worst manures frequently have as good a chance as the very best. Then, again, you cannot control diseases in plants. You will often find that diseases in a mysterious way attack the wheat crop ; and the fly carries off the turnip plant. All these matters have to be well weighed before you can really come to a just con- clusion respecting the practical value of artificial manures. Now, I do not mean to say that in the long run the real value of any description of manure will not be clearly defined. Prac- tical experience has shown that only those manures which contain a large amount of ammonia, or a large amount of phosphate, or both, are really efficient manures. But, supposing you have ascertained that a certain description of manure is efficacious for a particular purpose, say the raising of turnips, how is the farmer to decide what he is to pay for it ? In other words, how can he estimate the money value of the artificial manures which he buys? Now, as hinted already, I would say, the practical value of a manure does not necessarily coincide with its money value. Lime on soils deficient in that substance produces a very powerful effect ; on some clay soils it is the manure which ought to be used ; but what will you say of a farmer if he gives for lime the same amount of money which he pays for guano ? With great propriety you will say he is a fool. Supposing such a person should say, " I don't care for the value of lime ; I want a good crop, and I am satisfied with the result ; " the man who sold him lime will have a good laugh at him. You may think that I am using exaggerated language, for nobody in his proper senses would reason thus ; but allow me to observe that there is no exaggeration if you replace the word lime by artificial manures. There are manures sold in the market which are not worth one quarter the d2 36 THE COMMERCIAL AND AGRICULTURAL money which is actually paid for them ; and it is the duty of chemists to point out the rascality of parties, for it is nothing else, of those who sell such manures. But with reference to the money value of a manure, and the benefits a farmer may derive from it, I beg to say, that to a hard-working labouring man a crust of bread and cheese is certainly as valuable, and it does him a great deal more good, than lobster salad ; but would he be right to pay as much for the bread and cheese as for lobster salad ? Certainly not. Supposing then, that two samples of superphosphate are sold at the same price, and in a certain place they produce the same results, would the farmer be justified in paying as much for the inferior description of superphosphate as he pays for the superior description? Certainly not. It is his business to determine what is wanted on his land, and if he finds that it requires dissolved bones let him pay according to the amount of bones which have been used in preparing the manure. In common life you do not estimate entirely the value of a thing by the benefit you derive from its possession. If you want a good plough horse you will ask what such a horse fetches in the market. Now why do you not ask in the same way what good superphosphate of lime fetches in the market? If you want a good turnip manure you ought to inquire what is the lowest price at which you can produce turnips ; for I have no hesitation in saying that turnips are often produced at too high a price. No fixed rules can be laid down in farming. Every man must use his own judgment, and inquire what is the best produce for him to raise under the circumstances in which he finds him- self situated. For my own part I would not condescend to recommend any manure, even if I could do so with propriety ; for it is not the part of any chemist to say, " This manure is a good one," or, " that manure is a better one.'* It is the chemist's business to ascertain the composition of a manure, and to estimate its value accordingly. Chemists, however, ought not merely to take into account the value of the constituents, but ought also to make a fair allowance for the skill and trouble which is incurred on the part of the manufacturer in the preparation of the manure ; for the mode of preparation often very greatly enhances the practical efficacy, as well as the commercial value, of the manure. Ma- terials in a raw state are much cheaper than they are in a prepared state. Take, for instance, a sack of flour. In the form of bread it is much dearer, because it has undergone preparation. The baker cannot be expected to bake for nothing, nor can tlie manure manufacturer be expected to dissolve his bones for nothing. It is fortunate for the farmers that there are men of the highest VALUE OF AKTIFICIAL MANURES. • . 37 degree of integrity and principle engaged in the manure trade, who make their living principally by the profit they gain in the purchase of the raw material ; but I am grieved to say there is another class of men engaged in the manure trade who know the weak sides of the farmers ; who know that a man who takes a reasonable percentage in the employment of his capital, will not condescend to have a long talk in his dealings ; indeed he cannot afford to have a talk of a couple of hours in length before he effects a sale. There are dealers who go into the market, and lay hold of the small farmer and talk him over over a glass of grog, and they will often say, " You need not trouble yourself about the composition of the manure, if you don't get a good crop of turnips I won't take any money for my manure." Another perhaps will say, " Never mind about the money now, ril take it in six or twelve months, or when it is convenient to you." The man who employs a large capital cannot wait so long for a return. In conclusion, allow me to illustrate the above remarks on artificial manures by a reference to a few fraudulent manures, and to impress upon you the necessity of paying much attention to the composition of artificial manures, which are offered for sale in the market. In the first place I beg to direct your attention to the sub- joined diagram, which represents the composition of two samples of the British Economical Manure, which have been referred to me for analysis. British Economical Manure. Water 36-52 13-43 Organic Matter 3 04 Oxide of Iron and Alumina 2-30 Sulphate of Iron 23-75 25-84 „ Lime (Gypsum) -86 32*42 „ Magnesia -20 Soda 15-14 18-40 Bi-sulphate of Potash 4-G7 Soda .. .. 10-92 Insoluble Silicious Matter (Sand) . . . . 5*85 3-3G 100-05 100-00 Containing Ammonia -68 -30 Many people have been sadly deceived in buying the British Economical manure, a manure which is sold at 12/. per ton, and consists almost altogether of materials possessing very little value. It will be observed that the first sample contains not quite three-quarters per cent, of ammonia, and the second sample not even one-half per cent., whilst phosphate of lime is altogether wanting in both samples. Instead of these valuable compounds, green vitriol or sulphate of iron, crude sulphate of soda, or as it 38 THE COMMERCIAL AND AGRICULTURAL is technically called, salt-cake, gypsum, and sand constitute the chief ingredients of this manure, which professes to be superior in efficacy to the best Peruvian guano. It will strike you that the second sample contains a very much larger amount of gypsum, and is mach drier than the first sample. When first brought out the manure was found too wet, and therefore was objected to by many farmers, who in general like a manure that runs easily through the drill. To remedy this defect the ingenious proprietor of the economical manure intro- duced into its composition a large quantity of gypsum, a cheap material, which answers exceedingly well the purpose of drying up moist substances. In this dry condition the economical manure is now generally sold, but its composition is by no means constant, for the pro- prietor has no manufactory of his own, and gets his manure made as best he can. It is made in various parts of the kingdom, generally in localities where chemical manufactories abound, as in the neighbourhood of Liverpool, Bristol, Glasgow, Newcastle, and Londoa By paying a handsome profit to the chemical manufacturers, who in many instances are but too glad to dispose of their refuse mate- rials, the proprietor of the British Economical Manure engages the interests of the manufacturers, and by giving a commission of 1/. to 21. for the sale of every ton of this manure he secures agents in all parts of England to dispose of the all but worth- less stuff. In the next place, let me point out to you in the subjoined diagram the composition of two manures, one of which is called Mexican guano, and the other professes to be the very essence of Peruvian guano : — Guano (so called). Mexican. Essence of. Water 5'33 8-28 Organic Matter 3'52 13-11 Oxide of Iron and Alumina .. 3*59 Phosphate of Lime 18-10 2*35 Sulphate of Lime (Gypsum) 15*17 Carbonate (Chalk) 69-75 8-00 Chloride of Sodium (common Salt) .. 1-75 15-80 Insoluble Silicious Matter (Sand, &c.) . . . . 34*29 Magnesia 1-35 Loss .. 20 100-00 100-50 Containing Nitrogen 19 52 Equal to Ammonia 23 64 Large quantities of this so-called Mexican guano were sold not long ago at a high price, notwithstanding its inferior composition. VALUE OF ARTIFICIAL MANURES. €^ It is true the Mexican guano is not quite as bad as the " Econo- mical manure," for it contains 18 per cent, of phosphate of lime, which you well know is a valuable fertilizing constituent ; but it is a farce to call a manure, which contains nearly 70 per cent, of carbonate of lime or chalk, and a mere trace of ammonia, by the name of guano. The analysis shows plainly the true character of the so-called Mexican guano, which in reality is nothing more or less than sea-sand, containing a certain amount of fragments of fish-bones. With respect to the second manure given in the above diagram, I would observe that a more fraudulent case, excepting the British Economical, has never been brought under my notice. Instead of 16 per cent, of ammonia, which good Peruvian guano contains, this essence has only six-tenths per cent., and instead of 20 to 25 per cent, of phosphate of lime or bone-earth, only two to three- tenths per cent. The examination, indeed, has shown that this " essence of guano " contained a mere trace of Peruvian guano, a large quantity of gypsum, lime, sand, brick-dust, common salt, and sheep's dung. So clumsily was the mixture made, that the last-mentioned ingredient could be readily identified by its characteristic form. How is it, it may well be asked, that such and similar manures can find purchasers in an enlightened country like England ? The answer to this question is to be found in the credulity of many, who, strange to say, place more reliance upon printed testimo- nials, than upon the only trustworthy means of ascertaining the value of manures, i. e. chemical analysis. Let me guard you against being deceived by enticing testimonials, for, generally speaking, the worse the manure the more favourable the testimo- nials. Gas-lime, road-scrapings, peat-ashes, and similar refuse matters, in a more or less disorganised state, can be sold, as shown by actual experience, at high prices, and the most favour- able testimonials respecting their efficacy can be obtained, if an originator of a fraudulent manure makes up his mind to spend a couple of thousand pounds in advertisements, getting up testi- monials, and otherwise pushing his manures. I feel much tempted to bring under your notice other fraudu- lent manures, which are at the present time largely advertised in agricultural periodicals, but the cases just mentioned I trust will suffice to put the unsuspecting farmer on his guard. It must not be supposed, however, that fertilisers of recognised merit, such as guano or superphosphate, offer no temptation to the unprincipled dealers to fleece the unwary. Indeed, guano and superphosphate are as much adulterated as any other descrip- tion of artificial manure, and it may not therefore be amiss to allude briefly to the composition of good and inferior guanos, 40 THE COMMERCIAL AND AGRICULTURAL and the circumstances which principally determine the value of superphosphate of lime. In the following Table is stated the composition of four different samples of guano, all professedly Peruvian guano : — Composition of Guano. Water Organic Matter and Ammonical Salts . . Phosphates of Lime and Magnesia (Bone) Earth) i" Alkaline Salts, chiefly Chlorides of Po-1 tassium and Sodium j Gypsum Insoluble Siliceous Matter Yielding Ammonia 12-42 52*98 25*06 8*26 i''50 100-23 17-21 12-00 59-11 19-31 8-13 1-45 100-00 19*30 11-32 36-58 30-98 6-62 14*50 100-36 11*80 11-54 19-79 42-93 4-78 1-70 9-36 100*00 4-35 The two first-mentioned samples are genuine Peruvian guanos of excellent quality. The third is Peruvian guano of an inferior description ; the large amount of siliceous matter arises no doubt from the rock having been too closely scraped in collecting it. The fourth, though sold as Peruvian, appears to be in reality a Saldanha-bay guano of medium quality. Considerable differences thus occur in the composition of different samples of guano, sold as the above four samples, at the same prices. It is well to remember that the chief value of guano depends upon the amount of ammonia which it is capable of furnishing, and not upon that of phosphates and alkaline salts. A good Peruvian guano should contain from 50 to 60 per cent, of organic matter, yielding at least 16 per cent, of ammonia, 20 to 25 per cent, of bone-earth, 6 to 8 per cent, of alkaline salts, and no more than 2 per cent, of insoluble siliceous matter (sand). On burning genuine Peruvian guano it loses about two-thirds in weight, and leaves one- third of its weight of a perfectly white ash, which does not effervesce with an acid ; whilst adulterated guano generally produces on burning a much larger quantity of a reddish coloured ash, or a white ash, which either does not readily dissolve in dilute acid (showing the adulteration with gypsum), or strongly effervesces with an acid (proving the adulteration with chalk). Genuine Peruvian guano, moreover, weighs from 68 to 72 lbs. per bushel ; whilst adulterated guano weighs considerably more, no cheap material having been discovered with which guano can be readily adulterated without increasing its specific gravity. In purchasing Peruvian guano it is by no means necessary to VALUE OF ARTIFICIAL MANURES. 41 incur the expense of an analysis, for the composition of genuine Peruvian guano varies so inconsiderably, that a written guarantee of a dealer, stating to furnish Peruvian guano first quality as im- ported by Messrs. Gibbs, affords quite a sufficient safeguard. Unless a dealer is willing to give such a general guarantee, I would advise to have no transaction with him. There are men who guarantee Peruvian guano as imported by Gibbs, but sell you an inferior article, and yet give you no ground to lodge an action for damages. The fact is, every year cargoes of guano, damaged by .sea-water, are im- ported by Messrs. Gibbs, and sold by auction as D. or D. D. guano, i. e. damaged or double damaged. A party, therefore, who merely guarantees Peruvian guano as imported by Gibbs may sell you a damaged guano, and it is necessary, therefore, that you should get a written guarantee, in which the guano is warranted genuine Peruvian j^rs^ quality, as imported by Messrs. Gibbs. Such a general guarantee, however, is of no use whatever in buying superphosphate of lime, for there is no standard whereby the genuineness of superphosphate can be tested. The fact is superphosphate can be manufactured at any price — from 47. to 12/. and upwards. The manufacturer, by meeting the tastes of his customers and the prices they are willing to give for this manure, can readily make any quality of superphosphate. If a cheap article is wanted he has only to dilute a certain quantity of dissolved bones with gypsum or ashes, or use coprolites for dissolving in acid instead of bone-dust. In buying superphosphate of lime you should therefore de- mand of the maker or dealer a guarantee, which will enable you to ascertain whether or not the maker of this manure is making a reasonable or an exorbitant profit. Such a guarantee is afforded solely in an analysis, or at least in a general statement, that the bulk of superphosphate shall contain a certain amount of soluble and insoluble phosphate of lime and of ammonia. For these three different fertilizing ingredients determine principally the agricul- tural and commercial value of superphosphate of lime. It is well to bear in mind that it is the soluble phosphate which renders superphosphate peculiarly valuable as a manure for root-crops, and that this soluble phosphate is worth at least three times as much as insoluble or bone phosphates. All really valuable samples of superphosphate, therefore, should be rich in soluble phosphate. A manufacturer who merely guarantees genuine superphosphate gives in reality no guarantee whatever. The following diagram gives the composition of five samples of commercial superphosphates, all sold at about the same price, i.e, from 6/. to 11. per ton : — 42 THE COMMERCIAL AND AGRICULTURAL Composition of Superphosphate of Lime. Water Organic Matter Soluble Phosphate of Lime . . Equal to Bone Earth Insoluble Bone Phosphate Hydrated Sulphate of Lime) (Gypsum) J Burned Gypsum Alkaline Salts . . Sand Per-centagc of Nitrogen Equal to Ammonia 19-26 16-12 6*38 (9-94) 22-16 25-10 6-16 5-82 100-00 1-66 2-01 2. 20-53 14-76 10-31 (16-09) 17-72 28-39 1-56 6-73 100-00 •853 1'065 3. 14-40 8-93 3 60 (5-61) 6-83 44-23 2-52 19-50 100-00 1-44 1-75 22-03 trace 8*55 (13 '33) none 24-42 40-46 2-41 2-16 100.00 17 20 20-39 27-79 5-02 (7-37) 1-.56 40-16 2-93 4-23 100-00 1-11 1-42 It will be observed how greatly these samples differ in compo- sition, and, consequently, also in relative value. Nos. 1 and 2 are both good superphosphates. No. 3, on the other hand, is much adulterated with sand and gypsum, and contains only 5*61 per cent, of soluble and G'8 per cent, of insoluble phosphate of lime. No. 4 is richer in soluble phosphate, but mixed with a great deal of gypsum, aud scarcely worth half the money at which it was sold. No. 5 is a superphosphate manufactured by a maker, of Wellington, who calls this poor manure, containing only 7*37 per cent, of soluble and 1*56 of insoluble phosphate of lime, with 1*42 per cent, of ammonia, an ammonia phosphate, although it contains less ammonia than many samples of ordinary super- phosphates. It cannot be surprising that men who have the impudence to ask 6Z. per ton for such a superphosphate as that mentioned under No. 5 can have the impertinence to tell agriculturists that of all crops turnips require least phosphate in a manure, and that therefore a superphosphate containing much soluble and inso- luble phosphate is not a valuable manure for root-crops. The Mayor (who occupied the chair at the lecture delivered at Barnstaple) announced that discussion was invited on the subject of the lecture, and that the Professor w^ould have much pleasure in answering any questions which might be put to him. Mr. R. Gregory (guano merchant) expressed his pleasure in listening to the excellent lecture. The lecturer had admitted that guano was most congenial to the wheat plant, and superphosphate for the tui'nip crop. That doctrine he had of late heard disputed ; but whether those who entertained a conti-ary opinion had been labouring under a delusion or not it was difficult to say. Many gentlemen present contended that guano was more congenial and more VALUE OF ARTIFICIAL MANURES. 43 productive to the root crop than superphosphate. He was, therefore, anxious to have that question decided. Professor Voelcker thought there could be no question about the efficacy of guano both in the cultivation of the turnip and wheat crops. Experience had, however, shown that phosphates were Jteculiarly valuable in the root crops. It mattered little whether they were in bone-dust or guano ; but the question was in what form could we get them cheapest, and he thought that if they bought a good superphosphate, they must necessarily get phosphate cheaper than they could get it in guano. Now he had come to this conclusion from experiments which he had prosecuted, that a small quantity of ammonia was extremely useful for the turnip crops. As a manure, they would find 3 cwt. of super- phosphate and 1 cwt. of guano very good ; but if they depended entirely on their guano as a manure for their tm-nips, they w^ould throw away the greater part of the most valuable — commercially speaking — constituent, namely, ammonia. Mr. How asked what percentage of soluble and insoluble phosphate should a superphosphate contain to be a good and genuine article ? Professor Voelcker said it must be the object of the manufacturer to pro- duce soluble phosphate, which was a material the farmer could not produce conveniently. It might answer in certain cases to mix bone-dust with it ; but this the farmer could do himself. The value of phosphate depended principally upon the amount of soluble phosphate it contained ; and the more soluble it contained the more the manufacturer had a right to expect for it. Mr. How repeated his question, upon which Professor Voelcker said he ought to frame his question in this manner — What ought a manufacturer to charge for a quantity of soluble phosphate ? Mr. How did not understand what amount of soluble and insoluble phosphate a ton of superphosphate should contain. Professor Voelcker said it would depend upon the price. Mr. How. — Say 81. a ton. Professor Voelcker said perhaps the gentleman who had put the question would forgive him if he declined answering it, because it would be injudicious to interfere with the trader in his competition with others of his class. The more soluble phosphate superphosphate contained the better ; and let those who could supply the larger quantity of soluble phosphate get the best sale for it. It was not the business of the chemist to fix prices, but to guard farmers against being grossly taken in. Mr. Gregory could not help bringing to his recollection the fact that when the London Economical manure, which had been referred to by the learned lec- turer, first came out, the books which were published in its favour contained copies of testimonials from persons who had tested it and who alleged that it answered ; but when it appeared it was almost useless. He made these remarks to assure the meeting that testimonials were often a perfect humbug. Mr. Young (manure-merchant) had been exceedingly gratified with the lecture, and he believed every one present could similarly express himself ; but he would mention that they in that part of the kingdom had but very few opportunities of meeting with a gentleman so well acquainted with agricultural subjects to afford the information they required. He believed that bones con- tained, besides phosphate of Ume, another matter known by the name of gela- tine, which he understood was considered of some value. There were manu- facturers, however, who extracted from bones this gelatine, which they sold for the purposes of sizing. He asked if it was not advisable to make one-half of the phosphate of lime soluble and the other half insoluble ? Professor Voelcker would leave that question entirely to the judgment of the manufacturer and the farmer to find out which answered them best. Mr. Gr. H. Cotton said that it had been stated that it was desirable to mix guano witS common salt or burnt clay. As common salt was a cheap article, it occurred to him that farmers would be glad to know in what proportions the lecturer would recommend it to be mixed. 44 THE COMPOSITION OF FERTILE AND BARREN SOILS. Professor Voelckeb said that in his district they used one part of guano with two of salt. The Mayor said there was one part of the lecture he did not understand — perhaps it was from his ignorance of agriculture. It had liecn said that the value of superphosphate depended upon the quantity of soluble and insoluble phosi)hate which it contained. What appeared to him material for agricul- turists to know was, how they could ascertain that quantity. Professor Voelcker said that was a very important question. He would answer that it was i^erfectly impossible for any one to estimate the value of a sample of superphosphate merely by insjxiction. There were hundreds of samples brought to his notice throughout the year. It was no use smelling or tasting the superphosphate, for by this means they were unable to decide which was the best. There was only one means of ascertaining it, and that was by ascertaining what it contained. It was unreasonable on tlie part of dealers to ask the farmers to have their manures analysed, for a careful analysis could not be made under a guinea, and that was a heavy charge for a purchaser to pay. He advised all purchasers to procure a guarantee when they bought a manure. Somehow or other the dealer of an adulterated article would slip out of the obligation. Many of them would advise their purchasers to have their manures analysed, and would tell them that if they were not up to the standard they would " take something oft' ;*' and the purchasers after all might get deceived by an analysis. He had before him analyses of a manure, called " Binn's Patent Manure." In the prospectus it was said that the manure was sold at a very low price, and that the analyses had been made by Professors Way and Campbell. [Dr. Voelbker here read the results of the analyses, which showed that a portion of the constituents of the manure consisted of mere rubbish, and only 4 jx)r cent, of phosphate of hme.] The analyses were honest, and even offered a condemnation of the manure ; but this only showed them that they could not form any idea of the superiority or inferiority of manures from the name attached to an analyses ; and if upon any occasion they found his signa- ture attached to an analysis, he advised them not to come to the conclusion, from that circumstance alone, that the manure was a good one. He had pro- posed to a meeting of the Bath and West of England Society that if any of the members of that society sent him a copy of an analysis, he would tell them in round numbers what it was wprth. Mr. Langdon, in Ixihalf of the agriculturists present, begged to offer their sincere thanks to the lecturer for his able lecture, and to say they were highly pleased at the lucid manner in which he had answered the questions put to him. The motion was seconded by Mr. Cotton, and carried unanimously, after which three hearty cheers were given for the lecturer. 3.— THE COMPOSITION OF FEETILE AND BAKKEN SOILS. [Delivered at Newton, January, 1857.] In passing through a country of even limited extent, every intel- ligent man must become aware of the great diversity of soils which he meets in his journey, and on inquiry he will find that the agricultural products of these varied soils are likewise subject to very great changes. It is evident there must be a cause, or various causes in operation to account for the different aspects and agricultural capabilities of the various soils which we meet THE COMPOSITION OF FERTILE AND BAHKEN SOILS. 45 with in such a journey ; and, without accounting fully for those differences, I will observe that one of the principal causes in opera- tion is the varied composition of the soils. No one who has paid any attention to the subject can doubt that the composition of soils must materially influence their properties, and consequently also their productiveness. I propose to point out to you to-day some of the chemical characters of fertile and of barren soils ; but before entering into detail I would observe that the chemical composition of soils alone does not account for the high fertility of some soils, or the sterility of others ; there are indeed many circumstances to be taken into account if we wish to form an accurate opinion respecting the fertility of land. The chemical composition of the soil is but one element, although an important one, to be considered in forming that opinion. Therefore, prior to pointing out the chemical properties of land, I will remind you of a few circumstances that influence its fertility. Circumstances influencing Fertility. It is well known that the mechanical condition of soils greatly influences their productiveness ; often land which under proper cultivation would produce good crops, for want of proper tillage, yields but indifferent ones ; and the introduction of improved agricultural implements, with greater attention to the mechanical working of land — especially heavy land — will no doubt be attended with great advantage, I attach great importance to the mecha- nical working of the land, having seen its value illustrated in various parts of England, for besides improving the mechanical condition of the land it conduces to chemical changes of the greatest consequence to the growth of luxuriant crops. Indeed it is impossible to follow some of the recommendations of Mr. Smith of Lois Weedon, Mr. Mechi, and other advocates for deep culture or repeated ploughing, harrowing, and other processes for working the soil, without augmenting the amount of available food for plants. Next, the depth of soil is to be taken into consideration in forming a just estimate of its capabilities, and of the means of improving it. It is very well to suggest deep ploughing, but I could show you land which would be ruined by deep ploughing ; and therefore we should be careful how we condemn .any practice prevailing in any particular place. We should never say this is bad farming, or that is good farming, simply because the former does not tally with our preconceived notions of farming, or because the latter agrees with them ; for in farming there is no general rule to be laid down ; you cannot say you must plough 6 or 8 inches deep, you must subsoil, or you must adopt one sort of tillage invariably, on all sorts of lands. It is impossible to do this ; and the farmer who would blindly follow recommendations, even if they proceed 46 THE COMPOSITION OF FERTILE AND BxiRREN SOILS. from high authorities in agricultural matters, would possibly find, to his loss, that he had much better have obeyed his own judgment, and acted on his own discretion. But the question is, how is he to form a correct opinion ? How can he be assured he is right in introducing improved methods of tillage ? Certainly, if he only blindly follows the practices of his forefathers, it is impos- sible for him to take advantage of the suggestions that are made from time to time by men well qualified to give an opinion ; it is impossible for him to apply with advantage artificial manures, for the true use of those manures requires a mind trained in, at least, the first principles of chemistry. Apply artificial manures simply because you are recommended to do so, and in nine cases out of ten you will be disappointed. Hence it is that we fre- quently find the good farmers of the old school, and who hitherto have secured a fair return for their money, setting their faces against all modern improvements, and decrying superphosphates and all other artificial manures. And in their position perhaps they are right ; for it is not the introduction of artificial manures alone that will enable a farmer to get a large crop of turnips or grain ; he requires to exercise his judgment in the purchase of a manure, and when he has it, he must again exercise judgment in applying it to the land. Without this judgment, it is safer to continue to use the farmyard manure ; for it is a universal manure, containing all the elements of fertility, all the substances which plants thriving luxuriantly require. In a word, if he is not acquainted with the first principles of chemistry, he had much better follow his own approved practice of farming than rush heedlessly into modern improvements, and apply artificial manures without ascertaining whether those manures are suitable to his particular soil or crop. Practice and Theory. Indeed, as we advance in agriculture it becomes more and more a rational Practice, and assumes more and more the form of an Art. Agriculture, in my belief, will never become thoroughly a science. The very nature of its object precludes this. Agri- culture bears in this respect a close analogy to the practice of medicine : in both cases it is well to lay down principles — or rather, to elucidate principles ; but in a very great measure we should depend on experiences (hear hear). In one farm we may produce one year only 20 bushels of wheat, and in another 30 bushels, though in both instances we follow exactly the same mode of tillage and use the same manure ; for we have not all the modifying influences affecting the result under control, and therefore we cannot shape, so to speak, agriculture into a science, or establish any invariable scientific rules for our guidance. We are dependent on the test of experience, and thus many results THE COMPOSITION OF FERTILE AND BARREN SOILS. 47 may be stated to the chemist which it would be irrational in him to dismiss, even if they should appear to be inconsistent with recognised chemical principles : he should rather suspect himself than find fault with the universal practice followed hy intelligent farmers. We may rest assured, that as a rule, a practice esta- blished throughout a large tract of country, and followed with success by acknowledged good farmers, has something to recom- mend it, and that it is based on sound scientific principles — principles of which we are perhaps altogether ignorant. It is indeed remarkable that the researches of the chemist in the laboratory, when they are carefully and honestly made, always confirm practice of the character just announced. I am rather deviating from my subject, but perhaps that deviation will not be altogether unprofitable. I am anxious to impress on the minds of the farmers that sound practice always tallies with theory, if it is based on a true foundation. There may be much which in the mind of the farmer is set down as theory, in which there is no theory at all ; which passes with him for science, but which is no science at all. What, after all, is science ? It is the systematic arrangement of a number of experiences. Those ex- periences can only be attained by constant attention to practical matters. Such experiences are not attained merely by reasoning, but by experimenting — used in its right sense. A farmer who cultivates his land well is continually experimenting ; he intro- duces a new plough, he cuts the soil a little deeper, or buys another manure, and thus he acquires experience ; but frequently the experience would be of much greater value to him if he could give the reasons for the good results that follow. Now, it is the object of the scientific man to account for the benefits that result from agricultural practice ; he does so by instituting experiments different in one respect although similar in another, to the farmer's experiments on his soil. The two stand on a level ; you experi- ment in the farm, and the chemist, who has any claim to be heard by the farmers, experiments in the laboratory. Mock Science, If one merely looks into works on agriculture, and then writes worthless articles for agricultural papers ; or rushes from one town to another, dashing through the country in an express train, just to satisfy his conscience by visiting such and such a county famed for its agriculture, and if he gets laughed at by practical farmers, it serves him right. There are people of this kind. They will rise from reading a work, perhaps by Professor Liebig, or any other celebrated agricultural writer, and being inflated with their newly-acquired knowledge, think there is nothing better to do than to tell some practical farmer who has been cul- tivating his land successfully, what he had best do to double 48 THE COMPOSITION OF FERTILE AND BARREN SOILS. its productiveness, call him a fool and an ignorant fellow if he does not follow their recommendation, use such and such a manure, and, in short, adopt that practice which they have picked up in a day or two from some book. You will generally find a man of this class is as ignorant of chemistry as the man he would advise. Put him into a laboratory, and he would not be able to distinguish a bottle containing soda from one containing potash. Men of this character deserve to be laughed at, for they do a great deal of mischief by their lecturing on farming and chemis- try. It is by their means that chemical science especially is brought into discredit among the farmers. Trustworthy Science. Returning to the subject of science and its agreement with good practice, you will find that its results are based on expe- rience just as are those of agriculture, and not merely on reason- ing. Reasoning is very useful both to the farmer and chemist, but it is by painstaking experiments that the object is attained. I sometimes think that the instances in which the practice of the farmer finds explanation and confirmation in the recent researches of the chemist, would afford a good subject for an illustrative lecture. Whether you take the chemistry of soils, plants, or manures, you will meet with numerous points of contact, showing the intimate connection of chemical science with practical agri- culture; but I am passing away from my subject — that of soils. Let me point out in the first place the Chemical Character of Soils. Analyses of Loamy Soils. Silica .. .. .. Peroxide of Iron Alumina . . Lime Magnesia . . Potash . . . . Soda Sulphuric Acid . . Phosphoric Acid Carbonic Acid . . Chlorine . . Organic Matter . . Water Loss Db. Anderson. Ko.1. No. 2. Soil. SubsoiL Soil. Subsoil. 63'1954 61-6358 74-3927 73-6416 4-8700 6-2303 4-7130 4-9230 14-0400 14-2470 5-5440 9-3830 •8300 1-2756 1-3913 -7189 1-0200 1-3938 •74G8 •8489 2-8001 2-1761 1-7142 •1540 1-4392 1-0450 -6788 •0367 •0911 •0396 •1006 •2060 •2400 •2680 •1460 •1640 -0500 .. •0098 •0200 -0068 •0060 8.5508 6-8270 6-3271 5-8554 2-7000 4.5750 4-4260 4-2510 99*8364 99-7342 100-1873 100^1885 THE COMPOSITION OF FERTILE AND BARREN SOILS. 4-9 Analyses of Clay Soils, by Dr. Yoelcker. Water driven off at 212^ Fahr .. Organic Matter and Water of Combination Oxides of Iron 1 Alumina . . . . / Carbonate of Lime Lime Magnesia Potash Soda .. Phosphoric Acid Soluble Silica Insoluble Silicates (fine Clay) Chlorine and Sulphuric Acid Carbonic Acid and Loss No.L 5.539 3-621 3-070 •740 .605 •269 •220 •386 1^450 84-100 traces 100-000 No. 2. 3-38 8'82 6'67 1-44 •92 1-48 1-08 1-51 72^83 traces 2-87 100-00 No. 3. 6-11 8-34 •41 1^49 •65 •04 80-69 traces 2-27 100-00 A fertile soil is one that contains all the substances which our cultivated plants require for coming to perfection — which con- tains them in abundance, and in such a state that they are readily assimilated by the growing plants. I am speaking chemically, not forgetting that the physical condition of the soil greatly in- fluences its agricultural capabilities ; but, not having time now to discuss the physical properties, I pass them by, observing that, although I am a chemist, I attach very great importance to the physical condition of soils. To ascertain the character of good soils, we cannot do better than examine those remarkable for their fertility. Such soils have been carefully analysed, and I will direct your attention to the above diagrams, which may illustrate the subject. On the diagram headed " loamy soils," you have two soils from the Lothians, remarkable for producing large crops of wheat. Then you have, under the head " clay soils," the analyses of three different soils, one from the valley of Evesham, in Gloucester- shire, likewise remarkable for their fertility. You observe that a great number of substances enter into the composition of these soils. You find silica, which is the chief constituent of all soils. We don't always find it in an uncombined state, in which it is familiar to you under the name of " sand " — this being a form of silica; but we find the same substance in combination with alumina, constituting the chief ingredient in clay soils, and in this form it is called a silicate of alumina : or, in ordinary lan- guage, sand and clay are two chief component parts of soils. You will also find lime amongst the component parts of tliose (fertile) soils — not in very large quantities, still in quantities sufficient to meet the needs of agricultural crops. Few soils are F. 50 THE COMPOSITION OF FERTILE AND BARREN SOILS. without lime ; all must contain it if they can be in a condition to produce good crops, for not one of our cultivated crops is des- titute of lime ; without it they cannot grow ; hence it is that in some soils a small dressing of lime produces a great effect. Lime is the third principal constituent of soils. The fourth and last principal constituent is organic matter arising from the remains of former crops — ^decaying roots and leaves. It is invariably present in fertile soils ; but I would observe that the proportion of organic matter does not determine the fertility of land. It was assumed at one time that the fertility of soils was regulated by the quantity of organic matter which they contained. If you take up an agricultural work published as late as 1800, or even 1850 — for I have found works of the kind as late as that — you will find a theory advocated that the more " humus " the soil contains, the more fertile it is. But this theory is not correct. Vegetable Moulds. Analyses of Fertile and Infertile Vegetable Moulds. Organic Matter and 1 combined Water} (humus) Potash . . . . Soda .. .. Ammonia Lime Magnesia Peroxide of Iron Protoxide of Iron Protoxide of Man ganese .. Alumina . . Phosphoric Acid Sulphuric Acid Carbonic Acid Chlorine Soluble Silica Insoluble Silicates) (Clay) .. MULDKR. No.L 12*000 1-026 1-972 •060 4-092 •130 9-039 •350 •288 1-364 •466 •896 6 ■ 085 P240 2-340 57-646 1-006 100-000 No. 2. 12^503 r430\ 2-069/ •078 5^096 •140 10* 305 \ •563/ •354 2*576 •324 1^104 6-940 1-382 2^496 51-706 •935 100 000 Dli. SrRENGEL. No. 3. ! No. 4. 10-90 : 16-70 •01 1-00 •20 6-30 9-30 •13 •17 trace 71-80 •19 '06 •13 -03 "64 •78 •11 •02 •01 81-50 -02 100-00 100-00 No. 6. 37-00 trace do. •32 •31 -52 •45 trace do. trace 61-57 100-17 No. 6. 90-44 -01 trace •55 •08 •12 •63 -02 •19 trace 7-96 100-00 No. 1 and 2 are fertile soils of a tract of land in North Holland, gained by embankment from the sea. No. 3. Rich vegetable mould. No. 4. Poor sandy mould. No. 5. Very fertile peaty mould. No. 6. Boggy ; very sterile land. THE COMPOSITION OF FERTILE AND BARREN SOILS. 51 " Humus " is another term for decaying organic matter ; you will find it in any soil that has been in cultivation for some time. The relative proportion of humus in soils varies exceedingly ; and you find very fertile soils on the one hand with, comparatively speak- ing, a small proportion of organic matter, and fertile soils on the other hand, with a large proportion of such matter. This will appear when you glance at the diagram headed " Vegetable Moulds." We call soils containing a considerable proportion of organic matter, vegetable moulds. The first on the table is a soil from Holland, which has been reclaimed from the sea, and is extremely fertile ; it contains a large quantity of organic matter ; but you would be wrong to estimate the fertility of the soil by the abund- ance of the organic matter. Other circumstances are to be taken into account, for you observe the No. 6 soil contains 90 per cent, of humus ; there is very little else in the soil but organic matter and some sand ; it is simply a peat soil, and the very appearance of a peat soil shows that the organic matter cannot ensure its fer- tility — indeed, in some instances, it is desirable to destroy the organic matters. You will find that farmers of the old style stick up for the presence of organic matters, and advocate the fertility of those matters, while putting lime to them, which has the effect of destroying them— for it is one of the beneficial effects of lime, that it does destroy organic matter when in that state most com- monly known as sour humus, although it is not more sour than other organic matters undergoing decomposition. It is one of the actions of lime to convert sour humus into useful matter ; the farmers then call it sweet. But the very terms of sweet and sour show there is something wrong in their theory of the fertility of humus. Assuming there is a land which is suffering from excess of organic matter in a certain condition, the farmers would say — *' Your humus is sour ; you want sweet humus ; lime neutralises the acid and makes it sweet." But it is altogether a theoretical speculation ; and it is astonishing to see how men, who are not accustomed to the modern way of chemical and scientific re- search, are led continually into theorising. There seems no man so apt to theorise as the imperfectly instructed. Here we have a soil (peat) with a vast proportion of organic matter, and it is worth nothing until it has undergone radical improvement ; and we perceive that what characterises fertile soils is not the mere prevalence of one constituent, but the presence of a number of substances all necessary for the life of our plants. E 2 52 THE COMPOSITION OF FERTILE AND BARREN SOILS. Sanely Soils. Analyses of Sa^^dy Soils by Dr. Sprenget.. No.l. No. 2. No. 3. No. 4. No. 5. ,No. 6. Silica and Quartz Sand . . Alumina Oxides of Iron .. ,. Oxide of Manganese . . Lime Magnesia Potash Soda Phosphoric Acid .. Sulphuric Acid Chlorine Organic Matter (humus) 96-000 •500 2^000 trace •001 trace do. do. do. do. 1^499 92-014 2-652 3-192 -480 •243 •700 •125 •026 -078 trace do. •490 90-221 2-106 3-951 •960 -539 •730 -066 •010 •367 trace •010 1-040 98-8 •6 •3 •1 •1 96-7 •4 •5 trace -1 trace do. do. do. •1 2-2 94-7 1-6 2-0^ l^O trace } '■'.. trace •5 100^000 100-000 100*000 99-9 100^0 100 '0 No. 1. Barren sandy soil. No. 2. Poor sandy soil. No. 3. Good sandy soil. No. 4. Very barren drift ; sand. No. 5. Barren sandy soil. No. 6. Fertile sandy loam. Sandy soils are always loose, friable, porous soils. Most of them require constant manuring in order to produce remunerative crops, and therefore are called hungry soils. It is upon these soils that liquid manure is used with great advantage ; and on the whole all soluble manures, used in small quantities at a time, and applied in renewed doses, produce capital crops on the better descriptions of sandy soils, and even on the poorer sands. The chief constituent of sandy soils is silica. In some soils belong- ing. to this class the proportion of silica or sand rises as high as 95*98 per cent. ; such soils are always very sterile. Others con- tain less sand and appreciable quantities of organic matters, lime, potash, soda, phosphoric and sulphuric acids ; and such soils are naturally more productive. Calcareous and Marly Soils, Analysis of a Marly Soil from the neighbourhood of Cirencester. By Dr. A. Voelcker. Organic matter and water of combination . . 10*50 Oxide of iron and alumina .. ., .. .. 11-92 Carbonate of lime 19*9!^ Carbonate of magnesia '25 Potash -62 Soda -09 . Phosphoric acid '38 Sulphuric acid '04 Soluble silica 13-45 Insoluble silicates and sand 42*07 Loss -76 100-00 THE COMPOSITION OF FERTILE AND BARREN SOILS. 53 In marly soils we have a class of soils which resemble on the one hand clay soils, and on the other hand calcareous soils. Ac- cording to the proportion of lime and clay which they contain, they are more or less stiff, and, on the whole, belong to the better kinds of soils. Many marly soils produce naturally heavy crops of pulse, peas, and clover, and, when properly pulverised, also good root-crops. All marly soils contain more than 5 per cent., and not more than 20 per cent., of lime. When there is much sand mixed with the clay and lime in the soil, it is called a sandy marl ; on the other hand, if a marly soil contains much clay, it is termed a clay marl. Clay marls are often used with much benefit for im- proving light sandy soils. Analysis of a Calcareous Soil from the Farm of the Royal Agricultural College, Cirencester. By Dr. Voelcker. Organic matter and water of combination 6*339 Oxides of iron and alumina, with a trace of phosphoric acid 9*311 Carbonate of lime .. .. 54*566 Magnesia trace Sulphuric acid ditto Chlorine ditto Potash and soda 1*032 Insoluble silicious matter 28*947 100*195 The preponderating constituent in calcareous soils is lime. In chalky soils, as some of the calcareous soils resting on the great oolite, the proportion of carbonate of lime rises often as high as 70 to 80 per cent. Calcareous soils, in which lime pre- ponderates so largely, are, generally speaking, not very produc- tive ; but they are well adapted for the growth of leguminous plants, especially sainfoin, which tribe of plants appears to delight in calcareous soils. The physical characters, as well as the chemical composition of soils belonging to this class, vary ex- ceedingly, and also the agricultural capabilities and value of different calcareous soils. Those calcareous soils which contain a considerable propor- tion of clay are cold and difhcult to work, whilst others contain- ing more sand are lighter and more easily cultivated. Before proceeding further, I may be allowed to observe, that of all systems of classifying soils, the one in which soils are arranged in groups according to the preponderance of one of its four chief component parts — namely, lime, clay, sand, and organic matters — appears to me the most simple and practically useful. Accordingly soils may be conveniently classified as follows : — 54 THE COMPOSITION OF FEKTILE AND BARREN SOILS. 1 . Sandy soils, or soils containing above 80 per cent, of silicions sand. 2. Calcareous soils „ „ 20 per cent, of lime. 3. Clay soils „ „ 50 per cent, of clay. 4. Vegetable moulds (humus soils) „ 8 per cent, of organic matter, or Immus. 5. Marly soils, or soils in which the proportion of lime amounts to more than 5 per cent., but does not exceed 20 per cent, of the whole weight of the dry soil, and that of clay is more than 20, but less than 50 per cent. 6. Loamy soils, or soils in which the proportion of clay likewise varies from 20 to 50 per cent., but which contain less than 5 per cent, of lime, and all the different constituents in a finely pulverized state. Mineral Constituents of Plants, We owe a debt of gratitude to Professor Licbig for showing that those mineral constituents which we find on burning the grain of wheat, oats, barley, or grass, and on burning root-crops, are not merely accidental, but that they are essential ingredients ; that unless the plants you intend to grow find those materials in the soil you cannot grow them with success. Indeed, if they are altogether deficient, or if one of them is so — if phosphoric acid, for instance, is deficient altogether — its deficiency prevents wheat setting its seed. Experiments have been tried repeatedly in artificial soils composed of all the constituents that we find in the ashes of plants, with the exception of one which, like phosphoric acid, is of great importance to the formation of the grain of wheat ; the result was that the plant would grow to a certain point, and even flower, but it formed no grains, or only one or two imperfect ones. We must lay it down then as an established principle in agricultural chemistry, that, unless those mineral constituents that we find in the ashes of plants are present in the soil, or are sup- plied to it, the plants cannot be grown. It is also be remembered that soils remarkable for a high state of fertility contain some necessary constituents in inexhaustible supplies. The soils that we find here are in many instances clays, and contain a considerable quantity of the mineral matters tliat we find in the ashes of plants ; and we may draw on the resources of those mineral riches without fear of exhausting them — whilst in other instances, where the more important articles of mineral food are deficient in soils, the constituents withdrawn must be restored, if we do not wish permanently to detract from the cha- racter of the land. In clay and loamy soils it must be an object to the farmer to inquire how he can best get out of the land the substances needed in plants. He need not scruple in working his land well, or in taking from it without always giving back the same constituent that he has taken. Truly, theoretically con- sidered, nothing is clearer than that what you take out of the land must be restored ; and you may lay down rules for making THE COMPOSITION OF FERTILE AND BARREN SOILS. 55 a restoration of this kind — and in leases it is common to require the tenant to return to the land a certain quantity of a certain manure periodically — but these rules are not always wise. If I had to deal with my own land, I would let it to an intelligent farmer, and tell him to farm in the best way he could, for I am convinced that what would be for his profit would also be for mine. It is a sliort-sighted policy on the part of landlords that leads them to think the tenants would get too much out of the land, for they bind men down to established rules which prevent agricultural improvement. The theory no doubt is — give back to the land what you take from it ; but in cultivating rich loamy soils, or such clays as are found in the neighbourhood of Torquay, where the soil is formed from the decomposition of trap-rock, what is the use of putting back a little lime or phosphoric acid when you have in the soil itself inexhaustible stores ? If you have a good balance in the agricultural bank, never mind using it abundantly — employ capital in making it useful by working the soil, and by the judicious purchase of artificial manures con- taining those constituents that are not abundant in the soil. Clay soils admitting of this treatment are, therefore, very fertile, be- cause they contain most of the chemical substances that enter into the composition of plants ; and the question is, how can they best be got at ? How to make Minerals in the Soil available. With respect to many soils, it becomes a delicate question to decide whether their elements are best rendered educible by means of improved agricultural implements and machinery, or by the introduction of some artificial manure, such as ammonia, nitrate of soda ; for I would not trouble to put any mineral back in a rich clay soil. Theoretically, by this means the land would grow poorer in mineral constituents ; but, practically, having an immense store of mineral food, and every year taking out but very little, you will never exhaust it — not at least for centuries ; and your sole question is, how can you get at it ? Is the best means the use of improved agricultural implements, admitting air to every part of the soil, and facilitating chemical decomposi- tion of the rock substance, or the introduction of ammoniacal matters, which render certain constituents soluble and available for the use of the plant ? It is a delicate question to decide, and it can only be decided by the accumulated experience of the farmer and the chemist. Here, let me say, we could decide on many important points if we only had the cordial co-operation of practical farmers. We have a heap of matters to work upon, and we cannot arrive at results in them because they have to be brought to the test of experience. There are many things and 56 THE COMPOSITION OF FERTILE AND BAKIJEN SOILS. conditions quite true theoreticallj which are affected hy consi- derations of £. s. d. They may or may not be profitable. " Will they pay ? " is the question the farmer puts to the chemist ; but if the latter is a sensible man he will not give an answer to that question. How the Ckemist assists the Farmer. " It is the business of my life," says the agricultural chemist, '' to instruct you in the right principles of science as applied to agriculture ; I can assist you to understand those princ iples ; but your making of money is your business, not mine, and 1 give you hints which you may apply if you please ; on their proper use success depends in a great measure ; if you do not choose to apply them you may be left behind, and others, sharper or more deter- mined, will use them in the right way, and make them profitable." It is, in fact, altogether necessary that the farmer should use his own discretion as to the application of manures, &c. I will make this plain by reference to the composition of sandy soils. These soils are generally naturally sterile, or are capable of pro- ducing very little — they are called hungry soils, because they swallow up manure ; observe the difference between these soils and clay. Phosphoric acid is only just traceable in them; lime is greatly deficient ; indeed, they are made up almost entirely of silica, and remembering that plants do not live alone by silica, but by lime and j)liosphoric-acid and other things as well, we see why sandy soils require muc:h good manure. Farmyard manure would do ; it is a perfect manure, containing all the Constituents of the fertile soils ; whilst in most artificial manures we have only two or three of the most fertilising constituents present ; hence, there is danger in using, on bad land, special manures ; I do not think that special manures can be used extensively on very barren soils, constituted chiefly of silica, because in artificial manures we have special constituents — some of them, doubtless, the most important to fertility, and I would guard against being supposed to speak disparagingly of those manures, only they must be used with great judgment, when they will answer well ; but in sandy soils it is extremely hazardous to use artificial ma- nures alone. Soils of that kind recjuire a different process of cultivation, because they are deficient in requisite mineral sub- stances. Absorbent Powers of Soils. But there is another point which has to be taken into considera- tion in speaking of the composition of soils. I refer to the atmos- ])heric food which soils absorb, some in small and others in large Cj[uantities. Clay, which is of the class of fertile soils, has in a very high degree the power of absorbing ammonia, and other THE COMPOSITION OF FERTILE AND BARREN SOILS. 57 fertilising gases, from the atmosphere, while barren sandy soils do not possess the power. Moreover, all soils characterised by great fertility retain manurial substances for a much longer time than others which are what are called " hungry " soils. It is im- portant to bear this in mind, because it will influence our practice of applying manure to the land. We frequently hear a discussion about the use of long and short dung, or winter and spring ma- nuring, and 1 find in agricultural discussions each man closes his opinion with the words, " I know I am right," and thinks his opponent is wrong ; the discussion concludes, and each goes away exactly in the same mind as when it began — simply through not understanding that the advocates of long dung are right in one case, and the advocates of short dung in another particular case ; but the reason why they are right is unknown to one or the other, because each doggedly adheres to his opinion, an VOL. XVII.. PART I. ON THE COMPOSmON OF FARMYARD MANURE. It is generally admitted that the management of farmyard manure, as carried out in many parts of England, more especially in the western counties, is often attended with much loss in valuable fertilising matters. In a country in which large sums are annually expended by the farming community in the purchase of artificial food and foreign manures, it might naturally be expected that the utmost care would be bestowed on the treatment of home-made dung, and that in its preparation the suggestions of improved practice and modern science would frequently be called into requi- sition by the cultivator of the soil. Experience, however, teaches that this is far from being the case. It is, indeed, a matter of surprise, no less to the agricultural chemist than to the more in- telligent portion of the^ agricultural community, that there should exist on the one hand so much ignorance on the first principles involved in the management of farmyard manure, and on the other so much indifference as to the best means of preventing the deterioration of the most important of all fertilizers. For my own part, however, I cannot share the opinions of those zeal- ous and, no doubt, sincere agricultural reformers, who describe the practical farmer as adverse to every new improvement, and turning a deaf ear to the suggestions of modern science. I know well how little of what commonly passes as a law of nature, or a scientific principle, rests on a firm basis, and is derived from the constant recurrence of a number of well-established facts. I am well aware how many so-called improvements are the emana- tions of the heated imagination of empirical theorists, and how few of the suggestions of even eminent scientific men can be practically carried out with economy on a large scale. I there- "^8 2 4 Farmyard Manure. fore find it quite natural that the agriculturist, often bewildered, and scarcely knowing how to meet the difficulties that besot his path in carrying out modern improvements, should relapse into his old and accustomed course. The inquiry into the changes which farmyard manure under- goes in keeping, under- various modes of management, unques- tionably is a subject of great importance ; and I cannot help therefore expressing astonishment that it has not been taken up long ago, and submitted to a thorough and searching investiga- tion. Hitherto our knowledge of this subject has been altogether very narrow, and this limited knowledge is of such a general cha- racter that it could not have been attended with any marked general improvement in the management of farmyard manure. General, and, in several respects, superficial information on so important a subject will as little assist the practical farmer in husbanding his home-made manure as similar information in the cultivation of root-crops would enable him to grow an abundant and remunerative crop of turnips. Agricultural chemistry, it strikes me, has reached that point at which, in order to become really use- ful to the practical man, it can no longer be prosecuted with suc- cess by amateur chemists, nor even by scientific chemists, who do not throw their whole energy into the inquiry, and give their un- divided attention and time to this noble and eminently practical branch of applied science. This view appears to be daily gain- ing ground ; and the time is fast approaching when agriculturists will no longer look with a certain suspicion on scientific investi- gations, but hail them with pleasure, aud willingly render that practical assistance which chemists have long earnestly desired. Many important inquiries, which neither the analyst in his labo- ratory nor the farmer in his fields can solve alone, will then be brought to a happy issue, and the principle which the Royal Agricultural Society has adopted for its motto, "Practice with Science," then, and then only, will bring forth its choicest blossoms, and be crowned with abundant fruit. These thoughts were suggested to me on undertaking an ex- tended inquiry into the changes which farmyard manure under- goes on keeping, under different modes of management ; and I feel bound publicly to express my obligations to the enlightened Principal of our College, for the readiness with which he has met my wishes, and placed at my disposal horse and cart, men and manure, and, in short, that practical apparatus, without which 1 could not have entered on the investigation. During a period of more than twelve months my leisure and that of my assistant, Mr. Sibson (to whom I feel greatly indebted for his persevering zeal and skill in this laborious task), has been almost constantly Farmyard Manure. 5 occupied in studying the changes which farmyard manure under- goes on keeping. It is not my intention to write a paper on the best manage- ment of farmyard manure, a subject on which considerable di- versity of opinion prevails. I may do so, probably, at a future occasion ; for the present I purpose simply to lay before the reader the results of my practical and analytical experiments, and to accompany them with some remarks, which I trust may help to solve the question, how home-made dung ought to be prepared and kept in the most profitable manner, so as to develop t!ie full efficacy of the excrements of our domestic animals, and the litter, and to guard against loss in the fertilising constituents of dung ? In undertaking this investigaticm I encountered a difficulty, which every one must have felt in experimenting on farmyard manure, namely, the difficulty of obtaining a sample sufficiently homogeneous to serve as the basis for future operations. In ex- perimenting on fresh, or long dung, especially, it is no easy matter to incorporate the long straw uniformly with the more minutely divided droppings of animals ; perhaps altogether a perfect mix- ture of both cannot be realised, and we must therefore be satis- fied to make the mixture as Intimate as tlie nature of the materials will permit. I endeavoured to reach this point by employing two men for the greater part of the day in turning a considerable quantity of fresh long dung, composed of horse, cow, and pig dung. By frequent turnings and distributions of the droppings amongst the long straw I thus obtained a tolerably uniform sample of mixed farmyard manure, which served as the basis for all future experiments and analyses with fresh dung. In the same way, but more easily, a well-mixed sample of well-rolten dung, composed of horse-dung, cows' and pigs' manure, was obtained a month later. This rotten dung, however, was not from the same heap from which the fresh dung last mentioned was ob- tained, but probably had undergone fermentation for a period of more than six months. It was well fermented, dark brown, almost black spit-dung, taken from the bottom of a corner of the manure-pit, where the more perfectly decomposed manure is used to be kept. In order not to encumber the description of my experiments, and the statements of the results obtained in them, I shall give, in an Appendix to this paper, a brief account of the methods made use of in the performance of the following analyses. I may ob- serve, however, in this place that the water-determinations in the experimental heaps were made on the same day on which they were put up, and that the samples for analysis were taken at the same time. Farmyard Manure, Fresh Farmyard Manure. Difficult as it is to prepare several tons of dung of a tolerably uniform character for the experimental heaps, the difficulty is greatly enhanced when a sample fit for analysis has to be chosen. For analytical purposes large quantities are inadmissible ; and it becomes therefore a matter of great importance thoroughly to prepare the small proportion of manure which can be employed in actual analysis as carefully as possible. To this end I spread out a weighed quantity of about 20 lbs. of fresh dung, pre- viously well mixed in the manure-pit, thoroughly pulled it to pieces, and then allowed it to become air-dry, by keeping it for some days in a safe place, in a heated room. The partial loss in moisture having been ascertained by the dif- ference in the second weight, as compared with that of the first : the whole of the partially dried manure was passed through a common coal-sieve ; and the pieces of long straw which refused to pass through the meshes of the sieve were cut in small pieces with a large pair of scissors : 1 lb. of the partially dried and now much more thoroughly mixed manure was then dried in a water-bath, at 212°, until it ceased to lose in weight. The loss calculated for the original quantity of manure, and added to the loss which it sustained in becoming air-dry, gave the total per- centage of moisture in the fresh dung. Another quantity of the partially dried manure, amounting to 1000 grains, was employed for the analysis, taken in hand on the 3rd of November, 1854. This analysis furnished the following general results : — General Composition of Fresh Long Dung {composed of Horse, Cow, and Fig Dung). Made Nov. 3, 1855. In Natural State. Calculated Dry. Water 66-17 ^Soluble organic matter 2*48 7*33 Soluble inorganic matter 1'54 4*55 •flnsoluble organic matter 25*76 76'15 Insoluble inorganic matter 4'05 11*97 100-00 100*00 * Containing nitrogen •149 '44 Equal to amnaonia 'ISl *53 t Containing nitrogen .. '494 '146 Equal to ammonia *599 *177 Total per centage of nitrogen '643 1*90 Equal to ammonia '780 2*30 Farmyard Manure. 7 A delicate reddened litmus paper held over the fresh-mixed dung was not affected at first ; but after the lapse of a couple of hours, the red colour was slightly changed into blue, thus showing that this fresh dung contained but a very small quan- tity of free or, properly speaking, volatile carbonate of am- monia ; for it is in the state of carbonate, and never in a free and uncombined form, that ammonia is given off from putrefying substances. I have endeavoured to determine quantitatively the amount of volatile compounds of ammonia in fresh manure, by distilling about 1000 grs., mixed with about 8 ounces of water, into a vessel containing dilute hydrochloric acid. This glass vessel was connected air-tight with the retort on the one hand, and on the other with a bulb apparatus, used in nitrogen combustions, and containing likewise dilute hydrochloric acid. By this means very small quantities of volatile ammoniacal compounds may be thoroughly fixed, and obtained, on evaporation of the acid, in the receiving vessel and bulb apparatus as chloride of ammonium. In this and the following analyses the amount of ammonia in the volatile ammoniacal compounds contained in manure is given, and, for brevity's sake, called free ammonia. At the same time I have endeavoured to ascertain the proportion of ammonia which, after the volatile ammonia compounds are distilled off, remains behind in the manure in a fixed state. This portion is mentioned in the analyses as ammonia in the state of salts. Both the free ammonia, and ammonia in the form of salts, are included in the determinations of the total amount of nitrogen (ammonia) con- tained in the manure. The fresh manure analysed on the 3rd of November, 1854, contained in its natural state, and when perfectly dry — In Natural State. Calculated Dry. Per centage of free ammonia -034 '10 „ ammonia in the state of salts '088 '26 The amount of volatile ammonia, as well as ready formed am- monia, existing in the form of ammoniacal salts in fresh manure, thus appears to be very trifling. Since there exists no complete, trustworthy analysis of the ash of fresh farmyard manure, I thought it advisable to analyse sepa- rately the soluble and the insoluble portion of the inorganic matters present in farmyard manure. One hundred parts of the soluble inorganic matters in fresh farmyard manure were found to have the subjoined compo- sition : — c2 8 Farmyard Manure. Fresh Farmyard Manure. Analysis made Nov. 3, 1854. Com/position of Ash of portion Soluble in Water ^ Soluble silica 15*45 Phosphate of lime 19*44 Lime 4-30 Magnesia .. » '73 Potash 37*26 Soda 3*36 Chloride of Sodium 1*97 Sulphuric acid 3*49 Carbonic acid and loss 14*00 100*00 The portion insoluble in water on analysis yielded the follow- ing results : — Fresh Farmyard Manure. Analysed Nov. 3, 1854. Composition of Ash of^portion Insoluble in Water. Soluble silica 23*94 Insoluble silicious matter 13*86 Oxides of iron and alumina, with phosphates .. 14*73 Containing phosphoric acid (4*41) Equal to bone earth (9*55) Lime .. 27*92 Magnesia 3*54 Potash .. 2*46 Soda ^; -48 Sulphuric acid 1*76 Carbonic acid and loss 14*31 100*00 In the next table the composition of the whole ash which was produced by this sample of fresh manure is stated : — Fresh Farmyard Manure. Analysis made Nov. 3, 1854. Composition of the whole Ash. r Soluble silica 4*25 k Phosphate of lime . . Lime 5*35 1-10 15S Magnesia -20 S 10 Potash ■. 10-26 Soda -92 (M Chloride of sodium Sulphuric acid •54 . -22 CQ Carbonic acid and loss . 4*71 Arranged together 17-34 21-59 10*04 10-04 .. 5-35 es 8-47 8-47 (3-18) (3-18) (6-88) (6-88) 20-21 21-31 2-56 2-76 1-78 12-04 •38 1-30 .. -54 1-27 ]-49 10-40 15-11 Farmyard Manure. I Soluble silica Insoluble silicious matter (sand) . . Phosphate of lime Oxide of iron and alumina, with phosphates Containing phosphoric acid (^*^?) Equal to bone earth Lime Magnesia Potash Soda Chloride of sodium . . Sulphuric acid Carbonic acid and loss . . . . . . 100-00 100-00 Before offering any remarks on the composition of fresh manure, it may be well to insert in this place a table represent- ing the detailed composition of fresh farmyard manure : — Composition of Fresh Farmyard Manure (composed of Horsey Pig, and Cow Dung, about 14 days old). Analysis made Nov. 3, 1854. Detailed Composition of Manure in Natural State. Water 66-17 ♦Soluble organic matter .. .. 2*48 Soluble inorganic matter (ash) : — Soluble silica '237 Phosphate of lime -299 Lime '066 Magnesia 'Oil Potash .. .. -573 Soda -051 Chloride of Sodium -030 Sulphuric acid '055 Carbonic acid and loss 3. .. '218 1-54 t Insoluble organic matter 25-76 Insoluble inorganic matter (ash) : — Soluble silica -967 Insoluble silica -561 Oxide of iron, alumina, with phosphates . . . . -596 Containing phosphoric acid (-178) Equal to bone earth (-386) Lime 1-120 Magnesia -143 Potash -099 Soda -019 Sulphuric acid -061 Carbonic acid and loss -484 4-05 100-00 * Containing nitrogen . . -149 Equal to ammonia '181 t Containing nitrogen "494 Equal to ammonia -599 Whole manure contains ammonia in free state . . -034 in form of salts -088 10 Farmyard Manure. According to these results, the same manure in a perfectly dry condition will have the following composition : — Detailed Composition of Fresh Farmyard Manure in Dry State. *Soliible organic matter .. 7*33 Soluble inorganic matter (ash) : — Soluble silica .. .. .. .. "703 Phosphate of lime '884 Lime .. .. ' .. .. -185 Magnesia .. .. .. .. .. -033 Potash .. .. .. .." .. 1-695 Soda .. .. -153 Chloride of sodium .. .. ./ -089 Sulphuric acid 'OS^ Carbonic acid and loss *772 4-55 f Insoluble organic matter 76*15 Insoluble inorganic matter : — Soluble silica 2-865 Insoluble silica 1*659 Oxide of iron and alumina, with phosphates .. 1-404 Containing phosphoric acid (-528) Equal to bone earth ., (-822) Lime 3-335 Magnesia ,, , -424 Potash -294 Soda .. -077 Sulphuric acid .. .. ., -210 Carbonic acid and loss 1-722 11-97 100-00 * Containing nitrogen '44 Equal to ammonia '53 t Containing nitrogen 1-46 Equal to ammonia . .. ;. 1-77 Whole manure contains ammonia in free state .. -10 „ „ in form of salts -26 Fresh farmyard manure being composed of the droppings of horses, cows, and pigs, and the straw used for litter, according to the above determination, in round numbers consists of two- thirds of water and one-third of dry matters. Since this fresh manure was not more than fourteen days old, and no rain had fallen during the time it had lain in the dung-pit, all the water is due to the urine and the moisture of the droppings and litter. The quantity of straw employe'd as litter must necessarily affect the general composition of fresh dung, and more especially the amount of moisture which it contains ; but, I believe, we are not far wrong by saying that fresh mixed dung, in the production of which litter has been liberally supplied to the animals, when Farmyard Manure. 11 free from rain, consists of one-third of dry matters and two-thirds of moisture. An inspection of the analytical results just mentioned will further bring to view several interesting particulars; — 1. In fresh dung the proportion of soluble organic and mineral substances is small. This circumstance fully explains the slow action of fresh dung when compared with the effect which well- rotten manure is capable of producing. 2. The proportion of insoluble matters, more especially of insoluble organic matters, in fresh dung, on the contrary, is very large. By far the larger proportion of the insoluble organic matters consists of straw, changed but little in its physical cha- racter and chemical composition. In the sample of manure analysed the amount of insoluble organic matters is ten times as great as that of soluble organic matters, and the proportion of insoluble mineral substances nearly three times as large as the amount of soluble mineral matters. 3. Fresh dung contains a mere trace of ammonia in a volatile state of combination, and but a trifling quantity of ammonia in the form of ammoniacal salts. 4. The total amount of nitrogen contained in the soluble portion of fresh manure likewise is inconsiderable. Most of the nitrogen which, as we shall see by and by, is gradually liberated as the fermentation of dung progresses, is contained in the portion of the manure which is insoluble in water. In other words, com- paratively speaking, little nitrogen exists in fresh dung in a state in which it can be assimilated by the growing plants. Thus, in the sample analysed, the readily available amount of nitrogen in 100 lbs. of fresh dung is only '149 of a lb., whilst about four times as much nitrogen, or, in exact numbers, "494 lb., occurs in the insoluble portion of 100 lbs. of fresh dung. 5. A comparison of the composition of the organic soluble matters with the composition of the organic insoluble matters of fresh dung, however, shows that the former are far more valuable than the latter, inasmuch as the soluble organic matters contain a very much larger percentage of nitrogen, and in a state of com- bination in which nitrogen is available to the immediate use of plants. This will appear from the following numbers : — 100 parts of organic soluble matters in fresh dung contain 6*04 of nitrogen. 100 ,, insohible matters „ „ 1-92 „ In the same weight of each there is thus more than three times as much nitrogen in the soluble organic matters as in the insoluble organic matters. 12 ^ Farmyard Manure. 6. Witfi respect to tlie inorganic or mineral constituents of fresh dunof, it will be seen that it contains all those mineral matters which are found in the ashes of all our cultivated plants. 7. Comparing the composition of the soluble inorganic matters with that presented by the insoluble, no essential qualitative dif- ference is perceived between both, for the same constituents which occur in the soluble ash are found also in the insoluble ash. But there exists a striking difference in the quantitative composi- tion of the soluble and the insoluble mineral matters of fresh dung. 8. The principal constituent of the soluble ash of fresh dung, so far as quantity is concerned, is potash ; 100 parts of soluble ash, it will be seen, contain no less than 37*26 parts of real potash, or a quantity which is equivalent to 54*7 of pure carbonate of potash. The analysis of the soluble portion of ash of fresh dung gave only 14 per cent, of carbonic acid, including the loss in analysis ; and as 37'26 of potash take up 17'5 of carbonic acid in becoming carbonate of potash, and moreover mucii of the soluble lime existed in the water- solution as bicarbonate of lime, it is evident that a consi- derable quantity of potash is united with silicic acid in the soluble ash. 'I he large percentage of soluble silica (onfirms this view; fresh farmyard manure thus contains much soluble silicate of potash. 9. The large amount of soluble silica, both in the soluble and in the insoluble ash, are deserving notice. In the soluble ash this silica is united principally with potash, and probably also with some soda ; in the insoluble ash it is combined chiefly with lime, or exists in a finely divided state, in which it is readily soluble in dilute caustic potash. 10. The most prominent constituent of the soluble ash of fresh dung is silicate of potash. 11. The most prominent constituent of the insoluble ash is lime. 12. It is particularly worthy of notice that the soluble ash of even perfectly fresh dung contains a very high percentage oi phos- phate of lime. The proportion of phosphate of lime in the soluble portion of ash was in fact found to amount to no less than 19 J per cent, of the whole soluble ash, whilst the percentage of phosphate of lime in the insoluble ash was found to be only 9^. I must confess that I was not prepared to find so large an amount of a compound which is generally considered insoluble in water, and for this reason is not enumerated in the published analyses of farmyard manure amongst the soluble constituents of Farmyard Manure 13 (lun?. Repeated experiments, however, executed with all care to avoid any possible source of error, have shown me that water dissolves phosphate of lime or bone-earth much more rapidly and to a much greater extent than it has hitherto been supposed. This observation ^ains much in interest, if it be remembered that the late Mr. Pusey suggested many years ago a method of rendering: bone-dust more efficacious as a manure for root- crops. His plan was to place bone-dust moistened with water and mixed with ashes, sand, or other porous matters in a heap, and to keep this heap moist by pouring occasionally water upon it, or, better still, stale urine or liquid manure. The suggestion has been followed by many with much success. But few may have known that by adopting Mr. Pusey's plan of reducing bone- dust still further they have been instrumental in generating that combination which gives peculiar value to superphosphate of lime, namely, soluble phosphate of lime. In one of the latest numbers of the ' Annalen der Chemie und Pharmacie,' edited by Liebig, Wohler, and Kopp, Pro- fessor Wohler, of the University of Gottingen, makes the im- portant observation that bone-dust moistened with a little water, in the course of a few days yields a considerable quantity of phos- phate of lime to water, and that this solubility rapidly increases with the putrefaction oF the gelatine of bones. My analysis of farmyard manure, made a year before the recent notice, which Professor Wohler gave in the ' Annalen der Chemie,' respecting the solubility of phosphate of lime in water, may be regarded as a confirmation of Wohler 's direct experiments upon bone-dast, as well as an interesting scientific commentary on Mr. Pusey's practical suggestion of rendering bone-dust more efficacious as a manure for root-crops. 13. The insoluble part of the ash of fresh farmyard-manure includes the sand, earth, and other mineral impurities, which mechanically get mixed with the dung. Most of these impuri- ties are mentioned in the ash-analyses as insoluble silicious matter ; anotlier portion is comprehended under oxides of iron and alumina with phosphates ; and a third part, probably a consider- able portion of tlie mechanical impurities, is included under lime, for the gravel and soil at Cirencester abounds in carbonate of lime. Due allowance must be made for these mechanical impurities in all considerations respecting farmyard manure, otherwise conclusions will be drawn which the facts of the case do not warrant. 14. Chemically considered Farmyard Manure must, be regarded as a perfect and universal Manure. — It is a universal manure, because it contains all the constituents which our cultivated crops 14 Faiinyard Manure. require to come to perfection, and is suited for almost every de- scription of agricultural produce. As far as the inorganic fertilising substances are concerned, we find in farmyard manure : potash, soda, lime, magnesia, oxide of iron, silica, phosphoric acid, sulphuric acid, hydrochloric and carbonic acid — in short, all the minerals, not one excepted, that are found in the ashes of agricultural crops. Of organic fertilising substances we find in farmyard manure some which are readily soluble in water and contain a large proportion of nitrogen, and others insoluble in water and con- taining, comparatively speaking, a small proportion of nitrogen. The former readily yield ammonia, the latter principally give rise to the formation of humic acids and similar organic com- pounds. These organic acids constitute the mass of the brown vegetable substance, or rather mixture of substances, which, prac- tically speaking, pass under the name of humus. Farmyard manure is a perfect manure, because experience as well as chemical analysis shows that the fertilising constituents are present in dung in states of combination, which appear to be especially favourable to the luxuriant growth of our crops. Since the number of the various chemical compounds in farm- yard manure is exceedingly great, and many no doubt exist in a different state of combination from Ihat in which they are obtained on analysing farmyard manure, in our present state of knowledge it is impossible artificially to produce a concentrated, universal, and perfect manure, which might entirely supersede home-made dung. I do not refer to the mechanical effect which farmyard manure is capable of producing. This mechanical effect, especially im- portant in reference to heavy clay soils, ought to be duly regarded in estimating the value of common dung, but for the present it may suffice to draw attention to the fact, that even fresh dung contains a great variety of both organic and inorganic compounds of various degrees of solubility. Thus, for instance, we find in fresh manure volatile and ammoniacal compounds, salts of am- monia, soluble nitrogenized organic matters, and insoluble nitrogenized organic substances, or no less than four different states in which the one element, nitrogen, occurs in fresh manure. In well-rotten dung the same element, nitrogen, probably is found in several other forms. This complexity of composition — difficult, if not impossible, to imitate by art — is one of the reasons which render farmyard manure a perfect as well as a universal manure. Rotten Farmyard Manure. With a view of ascertaining the changes which farmyard manure undergoes in keeping, I submitted to analysis a well- Farmyard Manure. 15 mixed sample of rotten dung produced under the same circum- stances under which the fresh manure was obtained. The rotten dung probably was at least six months' old, possessed a dark- brown, almost black, colour, and appeared to be well-fermented, short dung. The general composition of this, dung is presented in the sub- joined Table : — Composition of well-rotten Manure (Mixed Horse, Cow, and Pig Dung). Analyzed Dec. 5th, 1854. In natural state. Calculated dry. Water 75-42 *Soluble organic matter 3*71 15*09 Soluble inorganic matter 1*47 5*98 tinsoluble organic matter 12*82 52*15 Insoluble inorganic matter 6*58 26*78 100*00 100*00 ♦ Containing mtrogen *297 1*21 Equal to ammonia *360 1*47 t Containing nitrogen *309 1*26 Equal to ammonia *375 1*53 Total amount of nitrogen -606 2*47 Equal to ammonia '735 3*00 I have determined in this manure likewise the proportion of ammonia present in a volatile form, as well as the ammonia which is disengaged on distilling with quicklime the residue, from which the free ammonia has been driven off, and have ob- tained the following results : — In natural state. Calculated dry. Percentage of free ammonia *046 '189 „ ammoniain form of salts (readilyj .q-„ .232 decomposed by quicklime) / The proportion of free ammonia in well-rotten dung thus appears not much larger than in fresh dung produced under the same circumstances ; and the amount of ammonia present in rotten dung in the form of salts, which are readily decomposed by quicklime, to be almost identical with that contained in the fresh manure. Further remarks on the composition of rotten dung I shall reserve until I have stated the composition of the soluble and insoluble ash and the detailed composition of the whole manure in its natural and dry state. In the following Table the composition of the soluble part of the inorganic matters in well-rotten farmyard manure is given : — 16 Farmyard Manure. Analysis made Dec. 5, 1854. Composition of Ash of Portion soluble in Water. Soluble silica 17*31 Phosphate of lime 26-00 Lime 7-97 Magnesia .. .. 3*24 Potash 30-37 Soda 1-60 Chloride of sodium 2-53 Sulphuric acid 393 Carbonic acid and loss 7*05 100-00 On comparing these analytical results with those obtained in the analyses of the soluble ash of fresh dung, it will be seen that the amount of soluble phosphate of lime (bone-earth) in the rotten dung is much greater than in the fresh. Phosphate of lime, next to potash, is the most abundant constituent of this ash. Other differences between the soluble ash of fresh and rotten dung are too trifling to call for any special remarks. On the whole, a close similarity in the composition of both is sufficiently apparent. The next table represents the composition of the insoluble ash of rotten dung : — Analysis made Dec. 5, 1854. Composition of Ash of Portion insoluble in Water. Soluble silica 21-65 Insoluble silica 15*35 Oxides of iron and alumina and phosphates .. 14*40 Containing phosphoric acid (4*17) Equal to bone earth .. .. (9*03) Lime 25*34 Magnesia 1*38 Potash -69 Soda -58 Sulphuric acid *96 Carbonic acid and loss 19*65 100-00 The same constituents which occur in the insoluble ash of fresh manure are found in the insoluble ash of the rotten dung in very nearly the same relative proportions. The insoluble ash of rotten dung, however, contains still less potash, as nearly all pot- ash is contained in the soluble ash. From the foregoing results the composition of the whole ash left on burning of well -rotten dung has been calculated. Farmyard Manure. 17 Analysis made December 5, 1854. Composition of whole Ash. r Soluble silica 3-16 f-l , 9. -^ Phosphate of lime 4-75 ■g ? Lime 1-44 ^ 8 Magnesia •59 •^S, Potash 5-58 0, ^ Soda •29 '^X Chloride of sodium •46 Sulphuric acid •72 Carbonic acid and loss 1-28 Arranged together. f" Soluble silica 17-69 20-85 Insoluble silica 12-54 12-54 Phosphate of lime 4-75 Oxides of iron, alumina, with phosphates 11-76 11-76 Containing phosphoric acid (3-40) (3-40) i=l iH Equal to bone earth (7-36) (7-36) •^ ^{Lime .. 20-70 22-14 p2 '^ rQ CO Magnesia 1-17 1-76 ::3 i^ Potash •56 614 d ^ Soda •47 •46 h^ Chloride of sodium •76 Sulphuric acid •79 1^51 Carbonic acid and loss 16^05 17-33 100-00 100-00 As the relative proportion of soluble to insoluble ash dif- fers in rotten from that in fresh dung, the composition of the whole ash of both presents some variations, observable especially in the amount of potash, which is much greater in the ash of fresh dung, and in a minor degree in the proportion of phos- phate of lime. In the next place I beg to direct attention to the subjoined Table, representing the detailed composition of rotten dung : — Analysis made Dec. 5, 1854. Detailed Composition of Manure in Natural State. Water ♦Soluble organic matter Soluble inorganic matter (ash) : — Soluble silica -254 Phosphate of lime '382 Lime '117 Magnesia ^047 Potash ^446 Soda ^023 Chloride of sodium .. .. -037 Sulphuric acid -058 Carbonic acid and loss -106 75-42 3-71 1-47 Carry forward 80-60 18 Farmyard Manure. Brought forward 80-60 flnsoluble organic matter 12'82 Insoluble inorganic matter (ash) : — Soluble silica 1*424 Insoluble silica 1*010 Oxides of iron and alumina, with phosphates '947 Containing phosphoric acid .. (-274) Equal to bone earth (-573) Lime 1*667 Magnesia *09I Potash -045 Soda -038 Sulphuric acid *063 Carbonic acid and loss 1*295 ^'^^ 100*00 * Containing nitrogen '297 Equal to ammonia *36 I Containing nitrogen *309 Equal to ammonia .. .. -375 Whole manure contains ammonia in free state . . *046 „ „ form of salts '057 Dried at 212^ F. the composition of this manure is as follows Composition of the same Manure in dry state. ♦Soluble organic matter 15*09 Soluble inorganic matter : — Soluble silica 1*035 Phosphate of lime 1*554 Lime -476 Magnesia '193 Potash 1*816 Soda -140 Chloride of sodium .. -151 Sulphuric acid *235 Carbonic acid and loss *380 5*98 flnsoluble organic matter 52*15 Insoluble inorganic matter : — Soluble silica 5*79 Insoluble silica 4*11 Oxides of iron and alumina, with phosphates 3*85 Containing phosphoric acid (I'll) Equal to bone earth (2*41) Lime 6*78 Magnesia *37 Potash .. -18 Soda -15 Sulphuric acid *29 Carbonic acid and loss 5*26 • 26*78 100*00 * Containing nitrogen . . .. .. 1*21 Equal to ammonia .. .. .. .. 1*47 t Containing nitrogen .. .. 1*26 Equal to ammonia 1*53 Whole manure contains ammonia in free state .. '189 „ „ form of salts '232 Farmyard Manure. 19 The comparison of these analytical results with the numbers obtained in the analysis of the fresh manure, exhibits several striking differences, to some of which I be"^ to direct attention. 1. The well-rotten dung contains rfearly 10 per cent, more water than the fresh. The larger percentage of water, it is true, may be purely accidental ; but, considering the tendency of the liquid excrements to sink to the lower part of the manure pit in which the rotten dung accumulates, I believe rotten dung will always be found moister than fresh dung upon which no rain has fallen. 2. Notwithstanding the much larger percentage of moisture in the well -rotten dung, it contains in its natural state, with 75^ per cent, of water, almost as much nitrogen as the fresh dung, with only 66 per cent, of moisture. Supposing both to be equally moist, there would thus be considerably more nitrogen in rotten dung than in an equal weight of fresh. This is clearly observed by comparing the total amount of nitrogen in the perfectly dry fresh and rotten dung. In the former it amounts to 1*90 per cent, of nitrogen, in the latter to 2'47. As far as this most valuable element is concerned, farmyard manure becomes much richer, weight for weight, in becoming changed from fresh into rotten dung. 3. During the fermentation of the dung the proportion of insoluble organic matters greatly diminishes ; thus the dry fresh manure contained 76 per cent, of insoluble organic matters, whilst there were only 52 per cent, in the dry rotten dung. 4. It is especially worthy of observation that, whilst the inso- luble organic matter is much reduced in quantity during the fermentation, the insoluble organic matter which remains behind in rotten dung is richer in nitrogen than an equal quantity of in- soluble organic matter from fresh dung. Thus 76 per cent, of insoluble organic matter of fresh dung contain 1*46 per cent., whilst 52 per cent, of it from rotten dung very nearly contain the same quantity, namely, 1*26. Or, — 100 parts of insoluble organic matter \ i .no x r -i. from fresh dung contain / ^^^ per cent, of nitrogen. lO parts of insoluble or^ from rotten dung contain 100 parts of insoluble organic matter ) „ -^ 5. On the other hand, the relative proportion of insoluble inorganic matters increases much ^during the fermentation of the dung, since dry fresh dung contains about 12 per cent, of insoluble mineral matters, and dry well-rotten dungs 2^'% per cent., or more than double the amount which is found in fresh dung. 6. But perhaps the most striking difference in the compo- 20 Farmyard Maim re. sition of fresh and rotten dung is exhibited in the relative pro- portions of soluble organic matter. Well-rotten dung, it will be observed, contains rather more than twice as much soluble or- ganic matters as the frfesh ; with this increase the amount of nitrogen present in a soluble state rises from '44 per cent, to 1-21 per cent. 7. Not only does the absolute amount of soluble nitrogenised matters increase during the fermentation of dung, but the soluble organic matters relatively get richer in nitrogen also. Thus, — 100 parts of dry organic soluble matter > 6-14 per cent, of mtrogen. from fresh dung contam I ^ •= 100 parts of dry organic soluble matter 1 g.^n frpm rotten dung contain I '* " 8. Lastly, it will be seen that the proportion of soluble mineral matters in rotten dung is more considerable than in fresh. 9. On the whole, weight for weight, well-rotten farmyard manure is richer in soluble fertilizing constituents than fresh dung, and contains especially more readily available nitrogen, and therefore produces a more immediate and powerful effect on vegetation. Bearing in mind the differences observable in the composition of fresh and rotten dung, we can in a general manner trace the changes which take place in the fermentation of dung. Farmyard manure, like most organic matters, or mixtures in which the latter enter largely, is subject to the process of spontaneous decomposition, which generally is called fermentation, but more appropriately putrefaction. The nature of this process consists in the gradual alteration of the original organic matters, and in the formation of new chemical compounds. All organic matters, separated from the living organism, are affected by putrefaction, some more readily, others more slowly. Those organic substances which, like straw, contain but little nitrogen, on exposure to air and moisture at a somewhat elevated temperature decompose sponta- neously and slowly, without disengaging any noxious smell. On the other hand, the droppings of animals, and especially their urine, which is rich in nitrogenous compounds, rapidly enter into decomposition, producing disagreeable-smelling gases. In a mixture of nitrogenous substances and organic matters free from nitrogen, the former are always first affected by putrefaction ; the putrefying nitrogenised matters then act as a ferment on the other organic substances, which by themselves would resist the process of spontaneous decomposition much longer. Without air, moisture, and a certain amount of heat, organic matters can- not enter into putrefaction. These conditions exist in the drop- pings of cattle and the litter of the stables, hence putrefaction Farmyard Manure, 21 soon affects fresh dung. Like many chemical processes, putre- faction is accompanied with evolution of heat. Air and water exercise an important influence on the manner in which the de^ composition of organic matters proceeds. Both are absolutely requisite in order that putrefaction may take place. Perfectly dry organic substances remain unaltered for an indefinite period, as long as they are kept perfectly dry. But too large an amount of water, again, retards the spontaneous decomposition of organic substances, as it excludes the access of air and prevents the ele- vation of temperature, both of which conditions greatly increase the rapidity with which organic matters kre decomposed. Al- though air is an essential element in the putrefaction of organic matters, the unlimited access is unfavourable to this process of spontaneous decomposition, and is productive of new (Changes. In farmyard manure the unlimited access of air is prevented by the compact nature of dung-heaps, consequently only a limited quantity of air can find its way into the interior of the mass. During the fermentation of fresh dung, disagreeable smelling gases are given off These arise principally from the sulphur, and from the phosphorus of the nitrogenized compounds present in dung. A considerable proportion of this sulphur and the phosphorus combine with hydrogen, and form sulphuretted and phosphoretted hydrogen — two extremely nauseous gases, which both escape from fermenting dung -heaps. Another portion of the sulphur and the phosphorus unites with atmospheric oxygen, and in the presence of porous substances becomes changed into sulphuric and phosphoric acid, two non-volatile compounds, which are left behind. We have seen the relative proportion of inorganic matters in well-rotten dung is much greater than in fresh. This increase in mineral matters can have only been produced on the expense of organic substances, the quantity of which during the process of fermentation must decrease in a corresponding relative degree. Thus the total amount of organic and inorganic matters in fresh dung, dried at 212° Fahr., is, — Organic matters 83*48 Inorganic matters 16-52 ]00-00 Whilst in rotten dung there are in 100 — Organic substances 68-24 Mineral substances 31*76 100-00 D 22 Farmyard Manure. It is clear therefore that, during the fermentation of dung, much of the organic substances must become changed into com- pounds which are either readily soluble in water, and easily washed out by heavy rains, or into gaseous products, which are readily volatilized. In point of fact, both volatile gases and readily soluble organic compounds are formed. Amongst the former, carbonic acid and ammonia deserve especial mention ; amongst the latter, soluble humates and ulmates may be named. These ulmates and humates are dark-brown-coloured compounds of humic and ulmic acids, with the alkalies, potash, soda, and am- monia. Ulmic and humic acids in a free state are scarcely soluble in water, and for this reason colour it only light brown. These prganic acids have a very powerful affinity for ammonia, in consequence of which they lay hold of any free ammonia, which is generated in the fermentation of dung, and fix it per- fectly, as long as no other compound is present or produced in fermenting dung, which at an elevated temperature again destroys the union of ammonia with humic, ulmic, and similarly consti- tuted acids. Now, ammonia is generated during the putrefaction of the nitrogenized constituents of dung in large quantities, and would be dissipated into the air much more rapidly than is the case in reality, if there were not formed in the dung itself a group of organic compounds, which act as most excellent fixers of the volatile ammonia. I refer to the humus substances, which are gradually produced from the non-nitrogenized consti- tuents of dung. In other words, the straw employed as litter during the putrefaction of dung is to a great extent converted into humic and ulmic acids, which fix to a certain extent the ammonia produced from the more nitrogenous excrementitious matters. The pungent smell of fermenting dung, however, shows that the volatile ammonia cannot be fixed entirely by these means. In the course of this inquiry I shall point out the reason of this, and content myself in this place by saying that the pro- portion of ammonia which passes into the atmosphere from fer- menting dung-heaps, and the loss which hereby is occasioned, is much less considerable than it is generally assumed to be. In fermenting dung-heaps the carbonaceous constituents at first are changed into humus substances, but these are rapidly oxidized by atmospheric oxygen, and partly changed into carbonic acid, a gaseous substance which, in conjunction with oxide of carbon and carburetted hydrogen, is given off abundantly from all putrefying organic matters. I have endeavoured to describe briefly the principal changes which take place in the fermentation of farmyard manure. It has been shown : — Farmyard Manure, 23 1. That during the fermentation of dung the proportion of both soluble organic and soluble mineral matters rapidly increases. 2. That peculiar organic acids, not existing — at least, not in considerable quantities — are generated, during the ripening of dung from the litter and other non-nitrogenized organic consti- tuents of manure. 3. That these acids (humic, ulmic, and similar acids) form, with potash, soda, and ammonia, dark-coloured, very soluble compounds. Hence the dark colour of the drainings of dung- heaps. 4. That ammonia is produced from the nitrogenous constituents of dung, and that this ammonia is fixed, for the greater part, by the humus substances produced at the same time. 5. That a portion of the sulphur and phosphorus of the excre- mentitious matters of dung is dissipated, in the form of sul- phuretted and phosphoretted hydrogen. 6. That volatile ammoniacal compounds, apparently in incon- siderable quantities, escape into the air. 7. That the proportion of organic substances in fresh dung rapidly decreases during the fermentation of dung, whilst the mineral substances increase in a corresponding degree. 8. That this loss of organic substances is accounted for by the formation of carbonic acid, oxide of carbon, and light-carburetted hydrogen, or marsh-gas. 9. That the proportion of nitrogen is larger in rotten than in fresh dung. The practical result of these changes is, that fresh manure, in ripening, becomes more concentrated, more easily available to plants, and, consequently, more energetic and beneficial in its action. It may be questioned, with much propriety, — Is this apparently desirable result attained without any appreciable loss ? or is it realised at too great an expense ? In other words. Is the fermentation of dung, or is it not, attended with consider- able loss of really valuable fertilizing substances ? In putting this question we have to bear in mind that the loss in valuable mineral matters, under proper management, practi- cally speaking, can be avoided, since they are non-volatile, and, therefore, must remain incorporated with the dung, if care be taken to prevent their being washed away by heavy falls of rain. We have likewise to bear in mind that, in an agricultural point of view, the carbonaceous, non-nitrogenized manure-constituents do not possess a very high intrinsic value ; and that we therefore need not trouble ourselves about their diminution, if it can be shown that it is accompanied with other beneficial changes. The d2 2lt Farmyard Manure. only other constituents which can come into consideration are the nitrogenized matters. The question may therefore be thus simplified : Is the fermentatioti of farmyard-manure necessarily attended with any appreciable loss in nitrogen ? Any one may ascertain that fermenting dung gives off am- monia, by holding over a dungheap, in active fermentation, a moistened reddened litmus-paper. The change of the red colour into blue sufficiently shows that there is an escape of ammonia. However, this experiment does not prove as much as is sometimes believed ; for inasmuch as the most minute traces of ammonia produce this change of colour, the escape of this volatile fertilizing matter may be so small that it is practi- cally altogether insignificant. Tlie comparison of fresh with rotten dung, we have seen already, does not decide whether or not fresh farmyard manure sustains a loss in nitrogen in becoming changed into rotten manure. Apparently there is a gain in nitrogen, for we have seen that rotten dung contains more nitrogen than fresh. This gain in nitrogen, however, is explained by the simultaneous disappearance of, relatively, a much larger quantity of carbonaceous organic matter. Still the accumulation of nitrogen in rotten dung is important, and hardly to be expected ; for, since a considerable portion of the nitrogenized organic matters is changed into volatile ammonia during fermentation, a loss, instead of a gain, in nitrogen naiurally might be expected. A much greater loss in nitrogen than is actually experienced would, indeed, take place during the fermentation of dung, if this pro- cess were not attended with the simultaneous formation within the manure-heap of excellent fixers of ammonia. Already at the beginning of my experiments I was thoroughly convinced that the mere analysis of farmyard manure would not decide the question which has just been raised, and therefore at once determined to make the analyses in conjunction with direct weighings of dung in various stages of decomposition. To this end I weighed out carefully two cartloads-full of the same well- mixed sample of fresh farmyard manure, the full analysis of which is given in the preceding pages. The manure was placed in a heap set against a stone wall, but otherwise exposed to the influence of the weather. The entire crude loss which this experimental heap sustained in the course of time was ascer- tained by periodical weighings on the weighbridge. Simul- taneously with these weighings the manure was submitted to analysis, and thus I was enabled not only to determine from time to time the loss in weight which the experimental heap sus- tained in keeping, but also to ascertain which constituents were affected by this loss, and in which relative proportions. I shall Farmyard Manure. 25 call this experimental heap "Fresh Farmyard Manure, No. I., Exposed." Another object I had in view was to examine the relative merits of various practical methods of the treatment of dun^ on the farm. This I endeavoured to attain by a series of strictly comparative practical and analytical experiments. For this purpose, I carefully weighed out two additional cartloads of fresh, well-mixed farmyard manure, taken from the same heap from which the experimental heap. No. I., was formed. It was placed next to the heap No. I., but sheltered from rain, sun, and sweepings winds by being kept under a shed. This heap will be described, in the following pages, as " Fresh Farmyard Manure, No. II., Under Shed." In order to examine the merits of making farmyard manure in open yards, I weighed out 1 cartload of the same fresh, well- mixed manure, and spread it evenly to about the same thickness in which manure is found under cattle in open yards, in an enclosed space, in close proximity to the other experimental heaps. This heap is called "Fresh Farmyard Manure, No. III., Spread." Finally, I put up a small heap of the same well -rotten dung, the analysis of which has been stated above. Like the experi- mental heap No. I., it was placed against a stone wall, but other- wise exposed to the influence of the weather. Under the name of " Well-rotten Farmyard Manure, No. IV,, Exposed," it will be described in the succeeding pages. All four experimental heaps were again weighed on the 14th of February, 1855, after having thus been kept for 3 months and 11 days. At the same time at which the weighings were made, samples of each were taken for analysis, and the water- determinations made immediately. Unfortunately, I discovered, just when the last heap was placed on the weighbridge, that the frost had impaired the accuracy of the balance, and I had, there- fore, no alternative but to reject the weighings in toto, and can supply therefore for this month only the analyses. Tliis is the more to be regretted, as I submitted samples of three of the ex- perimental heaps to a strict and detailed analysis. I trust, however, the subjoined analyses will not be void of interest. The following Table exhibits the comj)osition of " Experi- mental Heap No. I., Exposed," in its natural state : — <26 Farmyard Manure, Composition of Fresh Farmyard Manure (No. I.), Exposed, in Natural State, Taken for analysis, Feb. 14, 1855. Water 69-83 * Soluble organic matter 3'86 Soluble inorganic matter (ash) : — Soluble silica -279 Phosphate of lime 'SOO Lime -048 Magnesia '019 Potash 1-096 Soda .. .. ^ -187 Chloride of sodium -106 Sulphuric acid -160 Carbonic acid and loss '775 2-97 tinsoluble organic matter 18-44 Insoluble inorganic matter (ash) : — Soluble silica -712 Insoluble silica '857 Oxide of iron and alumina, with phosphates . . '810 Containing phosphoric acid (-177^ Equal to bone earth (-277) Lime 1-291 Magnesia -029 Potash -127 Soda -046 Sulphuric acid '099 Carbonic acid and loss -929 4-90 100-00 * Containing nitrogen -27 Equal to ammonia *32 t Containing nitrogen *47 Equal to ammonia -57 Whole manure contains ammonia in free state .. *019 „ „ in form of salts .. -064 The same manure, in a perfectly dry state, contains in 100 parts : — * Soluble organic matter 12*79 Soluble inorganic matter (ash) : — Soluble silica '924 Phosphate of lime *985 Lime -160 Magnesia *065 Potash 3-632 Soda -621 Chloride of sodium '351 Sulphuric acid -532 Carbonic acid and loss 2*570 9-84 Carryforward .. .. 22-63 Farmyard Manure. 27 Brought forward .. .. 22*63 tinsoluble organic matter 61*12 Insoluble inorganic matter : — Soluble silica 2*364 Insoluble silica 2*844 Oxides of iron and alumina, with phosphates 2*689 Containing phosphoric acid (*589) Equal to bone earth (*919) Lime 4*281 Magnesia *097 Potash .. .. *422 Soda *166 Sulphuric acid '329 Carbonic acid and loss 3*066 . 16.25 100*00 * Containing nitrogen '91 Equal to ammonia 1*10 t Containing nitrogen 1'55 Equal to ammonia 1*88 Whole manure contains ammonia in free state .. 0*62 „ „ in form of salts . . '212 Composition of Ash of 'portion Soluble in Water of the same Manure, Soluble silica 9*40 Phosphate of lime 10*12 Lime 1*63 Magnesia *67 Potash 36*92 Soda 6*32 Chloride of sodium 3*57 Sulphuric acid 5*41 Carbonic acid and loss 25*96 100*00 Composition of Ash of portion Insoluble in Water of the same Manure, Soluble silica 14*55 Insoluble silicious matter (sand) 17*50 Oxides of iron and alumina, with phosphates i . 16*55 Containing phosphoric acid (3*63) Equal to bone earth (5*66) Lime 26*35 Magnesia '60 Potash 2*60 Soda ,. -95 Sulphuric acid 2*03 Carbonic acid and loss 18*87 100*00 In the next Table is given the compositipn of the whole ash left on burning the manure. 28 Farmyard Manure. Composition of whole Ash of Fresh Farmyard Manure (No. I.), Exposed. 'Soluble silica .. .. .. 3-55 Phosphate of lime 3*82 1^ ^ CO U2 Lime .. .. ... .. '62 Magnesia "25 Potash 13-93 Soda .. 2-38 Chloride of sodium .. .. 1'35 Sulphuric acid ... 2-.04 Carbonic acid .... 9*80 Soluble silica .... .. 9.-06 Insoluble silica .. .. 10*89 Phosphate of lime .. .. Oxide of iron and alumina, with phosphates 10*30 Containing phosphoric acid (2*26) Equal to bone earth (3*62) Lime 16*41 Magnesia -37 Potash 1*62 Soda *59 Chloride of sodium Sulphuric acid 1*27 , Carbonic acid 11*75 Arranged together. 12*61 10*89 3*82 10-30 (2*26> (3-52) 17-03 *62 15*55 2-97 1*35 3*31 21-55 100*00 100-00 A comparison of these analytical results with the analysis wliich was made of the fresh manure, on the 3rd of November, 1854, will show : — 1. That there is more water in the manure on the 14th of February, 1855. 2. That, notwithstanding the larger proportion of water, the soluble organic and mineral matters have become more abundant, whilst the insoluble organic matters have become diminished in quantity. Thus, in November, the manure contained 2*48 per cent, of soluble organic matter, and 1*54 mineral substances ; and in February, 386 per cent, organic and 2-97 mineral substances; whilst the proportion of insoluble organic matters in November amounts to 25*76 per cent, and in February to only 18*44 per cent. These differences are still more striking, if we make the com- parison with the perfectly dry manure. It will then be found that the manure contained : — Nov. 3, 1854. per Cent. Soluble organic matters ... .. 7*33 Soluble mineral matters . . . . 4*55 Insoluble organic matter .. .. 76*15 Insoluble mineral matters .. .. 11-97 Feb. 14, 1855. per Cent. 12-79 9-84 61-12 16-25 100-00 100-00 Farimjard Manure, 29 3. That the total percentage of organic substances decreases, whilst that of mineral matters increases. Thus the fresh manure contained — In Nov, fn Feb. Organic matters 28-24 22-30 Mineral matters 5-59 7*87 And the perfectly dry manure — Organic matters €3-48 73-91 Mineral matters 16-52 26-09 4. That the percentage of nitrogen in the February analysis is slightly greater than in November. 5. That there is about the same inconsiderable amount of free ammonia, and ammonia in the form of readily decomposable salts, in the manure in February which has been found in November, 1854. 6. With respect to the inorganic constituents, a careful perusal of the furnished ash-analyses will show that the soluble portion of the ash of the February manure contains less phosphates of lime and less soluble silica, but more sulphuric acid, than the soluble ash of the perfectly fresh manure analyzed in November. The insoluble portion of the ash in February likewise contains less phosphates and soluble silica than in November, and the same differences will be observed on comparing the whole ash of February with that of November. It would appear thus that a three months' exposure to the weather has had the effect of removing from the manure an appreciable quantity of two very important fertilizing substances, namely, phosphate of lime (bone- earth) and soluble silica. I purposely abstain from pointing out minor difFerenceSj which will be observed in the November and February analyses of this manure ; for it must be borne in mind that, in experi- ments with farmyard manure, a perfectly uniform mixture can scarcely be obtained. Minor variations in the composition of the manure of November and February, therefore, may result as likely from purely accidental causes as from any real difference in composition. The particulars, however, just mentioned are sufficiently marked to prove that they are not due to accident, but to a series ojf changes which the fresh manure has undergone in the course of 3 months and 11 days. Fresh Farmyard Manure (No. II.), Under Shed. — Put up Nov. 3, 1854. Analyzed again in Feb. 14, 1855. The fresh manure used for all experiments was rather dry, no rain having fallen during the fortnight, in which the dung was collected from the stable, cow-house, and piggeries. 30 Farmyard Manure. Plenty of litter having been supplied to the animals, the fresh manure appeared to me drier than usual, and as the ex- perimental heap under shed necessarily must lose a good deal of moisture on keeping, I thought it desirable to pour water upon it, just sufficient to make it as moist as fresh dung generally appears. This addition of water, which was not re- peated, explains that the manure under shed contained a little more moisture in February, 1855, than when first put up in November, 1854. The following Table exhibits the composition of this manure in its natural state : — Fresh Farmyard Manure (No. II.), Under Shed. Analysis made Feb. 14th, 1855. Composition of Manure in natural state. Water 67'32 ♦Soluble organicmatter 2*63 Soluble inorganic matter (ash) : — Soluble silica -239 Phosphate of lime -331 Lime -056 Magnesia '004 Potash -676 Soda -192 Chloride of sodium '058 Sulphuric acid '119 Carbonic acid and loss '445 2-12 tinsoluble organic matter 20*46 Insoluble inorganic matter (ash) : — Soluble silica 1-893 Insoluble silicious matter (sand) 1*075 Oxide of iron and alumina, with phosphates . . 1*135 Containing phosphoric acid (298^ Equal to bone earth (646) Lime 1*868 Magnesia *078 Potash *208 Soda *038 Sulphuric acid -098 Carbonic acid and loss 1*077 7*47 100-00 * Containing nitrogen '17 Equal to ammonia 2*06 t Containing nitrogen "58 Equal to ammonia '70 Whole manure contains ammonia in free state . . 0*22 „ „ in form of salts 0-54 Farmyard Manure, 31 Composition of the same Manure in dry state, •Soluble organic matter 8 "04 Soluble inorganic matter (ash) :— Soluble silica .. .. 'TSS Phosphate of lime .. 1*013 Lime .. .. .. -171 Magnesia 'OlS Potash 2-068 Soda -578 Chloride of sodium '179 Sulphuric acid '366 Carbonic acid and loss 1*359 6*48 flnsoluble organic matter 62*60 Insoluble inorganic matter : — Soluble silica 3*294 Insoluble silica '. 5*800 Oxide of iron and alumina, with phosphates . . 3*477 Containing phosphoric acid (*91) Equal to bone earth (1*979) Lime 5*722 Magnesia '240 Potash -613 Soda -116 Sulphuric acid *302 Carbonic acid and loss 2*316 22*88 100*00 * Containing nitrogen *53 Fxiual to ammonia '66 t Containing nitrogen 1*77 Equal to ammonia 2*14 "Whole manure contains ammonia in free state . . 0*67 „ „ in form of salts 1*65 One hundred parts of the soluble portion of the mineral matters of the same manure contain : — Soluble silica 11*32 Phosphate of lime 15*64 Lime 2*64 Magnesia '21 Potash , 31*92 Soda 9*07 Chloride of sodium 2*77 Sulphuric acid 5*66 Carbonic acid and loss 20*77 100*00 One hundred parts of the insoluble portion of the ash of the same manure furnished the following results : — 3% Farmyard Manure. Soluble silica .. 25-35 Insoluble silica 14*40 Oxide of iron and alumina, with phosphates .. 15*20 Containing phosphoric acid (4*00) Equal to bone earth (8*66) Lime 25*01 Magnesia 1*05 Potash .. .. .. .. ;. ;. 2*73 Soda .. -51 Sulphuric acid 1*32 Carbonic acid and loss .. .. .. 14*43 100*00 Taking into account the relative proportions in which the soluble mineral matters are mixed with the insoluble in this manure, the composition of the whole ash left, on burning of the manure, has been calculated. Composition of whole Ash, produced by tJie same Manure. f Soluble silica 2*50 Phosphate of lime .. 3*45 1^ S 05 Lime Magnesia .. Potash .. .. Soda Chloride of sodium Sulphuric acid •58 •04 7-05 2*03 *6l 1*25 , Carbonic acid and loss 4*59 Soluble silica 19*74 Insoluble silica 11-21 Phosphate of lime Oxide of iron and alumina, with phosphates 11*84 Containing phosphoric acid .. .. .. (3*11) Equal to bone earth (6*74) Lime .. .. .19*48 Magnesia *82 Potash .. .. 2*12 Soda *39 Chloride of sodium Sulphuric acid 1*02 i Carbonic acid and loss 11*28 Arranged together. 22 24 11*21 3*45 11*84 (3*11) (6*74) 20*06 *86 9*17 2*42 *61 2*27 15*87 100*00 100*00 On comparing these results with the analyses of the fresh manure of November, 1854, it will be found that the manure kept under the shed for 3 months and 11 days has suffered very little change both as regards organic and mineral constituents. It will be perceived that the proportion of soluble compounds has very little increased in the course of this time, and that the per- centage of. nitrogen in the manure, practically speaking, has remained unaltered. Thus comparing the composition of the dry manure of February with that of the fresh of November, it will Farmyard Manure. 33 bo seen that the fresh manure contained in November 7*33 of soluble organic matter, and in February hardly 1 per cent, more, namely, 8*04 per cent. In the fresh, the percentage of nitrogen in the soluble organic matter is '44, and in the same manure kept 3 months 11 days under shed, the nitrogen amounts to "53 of a per cent. It also contains but a trifling amount of free ammonia, and ammonia in the form of salts. Apparently the manure has lost a good deal of organic in- soluble matter, almost as much as the exposed heap. If, how- ever, we scrutinize the results obtained in the analysis, it will be seen that the manure under shed contains a more considerable proportion of insoluble ash, and in this more lime and insoluble silicious matter, than occurs in the experimental heap (No I.) exposed to the weather for the same length of time. In the latter the mineral insoluble matter we would naturally expect to increase, since the soluble constituents are exposed to the solvent action of falling rain. The manure under shed cannot be subject to this deteriorating influence. If we find, notwithstanding, more insoluble mineral matters than in the manure exposed to the weather, it is plain that the larger amount of insoluble mineral matters, which causes the apparent diminution of insoluble organic compounds, can only be due to a larger proportion of mechanical earthy impurities in the sample analysed. In proof of this view of the matter it may further be stated that the manure kept under shed for another 3 months furnished even a little less insoluble mineral matter than in February. And as in the warmer spring months a more considerable diminution of organic substances has really taken place, as shown by the analyses to be mentioned hereafter, the excess of insoluble mineral matters in the February analysis can only be accounted for by mechanical impurities in the sample of which the analysis has been made. If we make due allowance for this disturbing influence, it will be observed that the composition of the soluble and insoluble portion of the ashes, furnished by the fresh manure in November, and of the same heap kept under shed for 3 months 11 days, is almost identical. It deserves to be noticed specially, that the ash of the manure kept under shed contains more phosphate of lime (bone-earth) than the ash produced by the heap exposed to the weather for the same length of time, during which the second experimental heap has been kept under shed. I also beg to direct attention to the fact that this manure, as well as the preceding experimental heap, contains more sul- phuric acid than the heap when first put up. On keeping of dung some of the sulphur, which we know occurs in nitrogenized substances in a peculiar state of organic combination, appears to 34 Farmyard Manure. become oxydised and changed into sulphuric acid, which acid entering into combination with lime, produces in its turn gypsum. Farmyard manure thus contains a quantity of gypsum, which becomes more considerable as the fermentation of the dung pro- ceeds. Without pushing deductions from this fact too far, it may be observed that it is interesting at all events to find that in the fermentation of dung, gypsum, a well known fixer of am- monia, is produced simultaneously with volatile compounds of ammonia. Besides the humus-like organic substances which we have seen are produced in fermenting dung-heaps, an additional fixer of ammonia, i. e. gypsum, is generated ; and thus great care is manifested by nature to prevent, if possible, the loss of this valuable fertilizing substance. Fresh Farmyard Manure (No. III.), Spread. The manure being covered with snow on the 14th of February, when the other experimental heaps were analysed, and it having been found next to impossible to remove the snow completely, or to mix it thoroughly with the manure, nothing was done in this month with the spread experimental farmyard manure. Well-rotten Dung (No. IV.), Exposed.— ?\xt up Dec. 5, 1854. Analysed again, Feb. 14, 1855. This experimental heap has been exposed to the influence of the weather for a period of 2 months and 9 days. During that time it had shrunk considerably in size. The diminution in bulk, however, I believe, is not so much the result of an actual very great loss, as it is due to the manure gradually settling down and becoming firmer. Still it has undergone some loss in keeping even during the cold time of the year, as will be seen from the subjoined analyses. In the state in which the well-rotten dung was analysed on the 14th of February it furnished the following results : — WeU-rotten Farmyard Manure (No. IV.), Exposed. Analysis made Feb. 14, 1855. Composition of Manure in Natural State. Water 73*90 ♦Soluble organic matter 2*70 Soluble inorganic n^atter (ash) : — Soluble silica -147 Phosphate of lime '129 Lime -018 . . Carry forward .. .. 76*60 Farmyard Manure. 35 Brought forward .. .. 76*60 Magnesia '018 Potash -960 Soda -082 Chloride of sodium '052 Sulphuric acid . . '072 Carbonic acid and loss '584 2-06 flnsoluble organic matter 14"39 Insoluble inorganic matter (ash) : — Soluble silica 1*10 Insoluble silica 1'54 Oxide of iron and alumina, with phosphates .. 0*37 Containing phosphoric acid ('06^ Equal to bone earth ('lO) Lime 2*25 Magnesia '02 Potash -12 Soda -01 Sulphuric acid '10 Carbonic acid and loss 1*44 6*95 100*00 * Containing nitrogen .. '149 Equal to ammonia '180 t Containing nitrogen '061 Equal to ammonia '074 Whole manure contains ammonia in free state • 01 5 „ „ in form of salts '048 Wdl-rotten Farmyard Manure (No. IV.), Exposed. Analysis made Feb. 14, 1855. Composition of Manure in Dry State, * Soluble organic matter .. 10*34 Soluble inorganic matter (ash) : — Soluble silica • '564 Phosphate of lime '493 Lime -067 Magnesia '068 Potash 3*680 Soda -321 Chloride of sodium '194 Sulphuric acid '278 Carbonic acid and loss 2*225 7*89 flnsoluble organic matter 55*13 Insoluble inorganic matter ; — Soluble silica 4*24 Insoluble silica 5*91 Oxide of iron and alumina, with phosphates 1*41 Containing phosphoric acid . . (*24) Carry forward .. .. 73*36 3B Farmyard Manure. Brought forward . . . . 73'36 Equal to bone earth .. .. .. ., .. ('SS) Lime . . 7"65 Magnesia '08 Potash -45 Soda .. .. -06 Sulphuric acid . . . , '38 Carbonic acid and loss 6*46 26-64 100-00 * Containing nitrogen ..-..•.... • . . . . '67 Equal to ammonia . . .^ . - . . -69 t Containing nitrogen 2*35 Equal to ammonia .. .. 2*85 Whole manure contains ammonia in free state . . -57 „ ,, in form of salts '183 Composition of Ash of Portion soluble in Water of same Manure. Soluble silica .. .. .. .. • ,. .. 7-15 Phosphate of lime . . . . 6*25 Lime .. .. -86 Magnesia .. .... -87 Potash 46-65 Soda 4-07 Chloride of sodium 2-47 Sulphuric acid .. .. .. » 3-52 Carbonic acid and loss . . . . • -. 28-16 100-00 Composition of Ash of Portion insoluhle in Water of same Manure. Soluble silica 15-93 Insoluble silica 22*20 Oxides of iron and alumina, with phosphates 5-30 Containing phosphoric acid (-93) Equal to bone earth (1-45 Lime .. .. 32-48 Magnesia -30 Potash .. .. .. .. 1-70 Soda -23 Sulphuric acid . . . . , 1-42 Carbonic acid and loss 20-44 it 100-00 Well-rotten Farmyard Manure. Analysis made Feb. 14, 1855. Caniposition of whole Ash. Soluble silica 1*63 Phosphate of lime 1*43 Lime ' -19 Magnesia '20 Potash 10-66 Soda -93 Chloride of sodium "56 Sulphuric acid . . '80 , Carbonic acid and loss 6*45 Farmyard Manure. 37 Arranged together. Soluble silica 12-13 13-70 Insoluble silicious matter (sand) .. .. 17-12 17-12 Phosphate of lime 1*43 Oxides of iron, alumina, with phosphates 4-08 4-08 Containing phosphoric acid (''''1) C'^'l) Equal to ijone earth (1-11) (Til) ^g,-{Lime 25-05 25-24 Mac^nesia '23 -43 Potash .. 1-31 11-97 Soda -17 riO Chloride of sodium '56 Sulphuric acid 1*09 1-89 .Carbonic acid and loss 15*97 22*41 100*00 100*00 A glance at these unaljticai results will show that the propor- tion of soluble organic matters in the well-rotten dung is smaller in February 1855 than in December 1854. It would thus appear that a portion of the soluble constituents has been washed away by rain or melting snow. As the heap was small, it was no doubt more readily affected by this deteriorating cause than a large heap would have been. It is moreover probable that the sample of the manure which was analysed in February did not fairly represent the whole heap. It appears to me therefore very likely that the proportion of soluble matters in the whole heap is in reality larger than is indicated by the foregoing analysis. It will further be observed that the dry manure in February contains about 2 per cent, less of organic matters than in December. We have thus here a direct proof that the proportion of organic matters decreases in dung-heaps even in the coldest months of the year — it is true in a less considerable degree than in summer, but yet to an appreciable extent. I would call attention to the manner in which the nitrogen is distributed amongst the constituents of this manure. When just removed from a well-constructed dung-pit in December 1854, 100 lb. of the perfectly dry manure contained 1*21 per cent, of nitrogen in the form of soluble compounds ; in February 1855, the soluble portion of the manure contained only *57 per cent, of nitrogen, thus showing that a portion of tlie soluble nitrogenized matters has escaped either into the air, or, what is more probable, has been washed out by the rain or melting snow. Notwith- standing this loss in nitrogen, the total percentage of nitrogen has become slightly greater by keeping for 2 months and 9 days. With respect to the free ammonia, it will be observed that rotten dung contains rather more free ammonia than fresh. The E 38 Farmyard Manure. free ammonia, which under all circumstances constitutes but a small fraction of a per cent, of the manure, however, sinks again in February to a mere trace. Direct experiments, made with a view of ascertaining the cause of this difference, have shown me that farmyard manure gives off no ammonia when quite cold, and that free ammonia can only be disengaged when the dung- heap is in an active state of fermentation, which is always accompanied with evolution of heat. In the interior of large heaps the heat of the dung is often very great, and it is in this part of the heap that ammonia is given off largely. Before, however, it can escape into the air it has to pass a portion of manure which is kept cold by the surrounding air. This external and cold part of dung-heaps acts as a mechanical and chemical filter with reference to the ammonia which is given off from the interior and heated portion of the heap. On account of the porous condition of the litter and partly dried excrements the ammonia is fixed mechanically ; but as all organic substances exposed to the atmosphere and moisture are gradually changed into humus, which as we have seen already is an excellent fixer of ammonia, the external parts of dung-heaps may also be called a chemical filter which prevents the loss of ammonia. Dung-heaps that have been placed in a field, after a short time, when settled down to a firm mass, do not give off any ammonia, but on turning such heaps a very powerful and pungent smell is readily perceptible. Each turning of a manure-heap thus is attended with a certain loss in ammonia, since it escapes from heated manure. It may therefore be advisable not to turn manure-heaps more frequently than is absolutely necessary. In the preceding pages I have given detailed organic and in- organic analyses of the fresh and the rotten dung in the state in which both were used in the experimental heaps. I have like- wise given such analyses of the fresh manure, after it had been kept for 3 months and 11 days in two different ways, and of the rotten dung after having been exposed to the weather for 2 months and 9 days. Another detailed analysis of the fresh manure, after having been spread out in an open yard for a period of 6 months, will be found in the succeeding pages. The various experimental heaps were weighed for the second time on the 30th of April, 1855, and at the same time samples for analysis taken from each heap. The two heaps made on the 3rd of November, 1855, with fresh mixed farmyard manure and the portion of fresh dung spread out in an open yard, thus were kept for 6 months, minus 3 days ; whilst the rotten dung, being placed in a heap on the 5th of December, was kept for only 5 months, minus 5 days. The loss in weight having been ascertained in each case, the Farmyard Manure. 39 manure was carted back in its former place and kept under the same respective circumstances until the 23rd of August, 1855, when aj^ain each experimental portion was weighed separately and again analysed. The rotten dung thus had been kept by the 23rd of August foF a period of 8 months and 18 days, the rest of the experimental manure heaps for a period of 9 months 20 days. Finally the different experimental heaps were weighed and analysed for the last time on the 15th of November, 1855. The rotten dung thus had been exposed to^he influence of the atmos- phere for a period of 11 months and 10 days, and the 3 re- maining experimental portions of originally fresh dung had been kept for a period of 12 months and 12 days. In order to render more conspicuous the results obtained in the direct weighings and in the different analyses, I shall incorporate them in separate Tables, which will be given under the respective heads of 1. Fresh farmyard manure, (No. I.) Exposed. 2 . . (No. II.) Under shed. 3 .. (No. III.) Spread. 4. Well-rotten farmyard manure, (No. IV.) Exposed. Before stating these details I may say that 1 have taken espe- cial care in determining accurately the nitrogen in each series of analyses. Frequently two combustions were made of one and the same substance, and invariably closely agreeing results ob- tained. Fresh Farmyard Manure (No. I.), Exposed (mixed horse, cow, and pig dung). In the subjoined Table is stated the actual weight of the first experimental heap at different periods of the year, and the loss which it sustained in these periods. Table showing the Weight of Experimental Heap of Fresh Farmyard Manure (No. I.), Exposed, at different periods, and Percentage of Loss in Weight, expressed in lbs. Weight of Manure in lbs. Loss in Original Weight in lbs. Percentage of Loss. Put up on the 3rd of November, 1854 . . Weighed on the 30th of April, 1855, or after) a lapse of 6 months ] Weighed on the 23rd of August, 1855, or after) a lapse of 9 months and 20 days . . . . j Weighed on the 15th of November, 185.5, or) after a lapse of 12 months, and 12 days .. J 2838 2026 1994 1974 812 844 864 e2 28-6 29-7 30-4 40 Farmyard Manure. In the course of a year and 12 days the original weight of this heap, amounting to 1 ton 5 cwts. 1 quarter and 10 lbs. thus became reduced to 17 cwts. 2 quarters and 14 lbs, by being exposed to the influence of the weather, or 100 tons lost 30-4 tons. We shall see presently in what this loss consisted. I may men- tion, however, already in this place that the direct weighings do not represent in an unmistakable manner the loss which farmyard manure undergoes in reality in keeping. We shall see, namely, that the loss during the las| 3 months is much greater than stated in the foregoing Table, after we shall have become acquainted with the composition, which the manure presented at the different periods, when it was weighed. In the first place I would therefore direct the attention of the reader to the following Table, in which is given the composition of the manure in the state in which it was found at the different experimental weighings. Composition of Fresh Farmyard Manure (No. I.), Exposed in Natural State, at different periods of the Year. When put up on the Feb. 14th, April 30th. Aug. 23rd, Nov. 15th, 3rd Nov. 1855. 1855. 1855. 1855. 1854. Water .. .. 66-17 69-83 65^95 75-49 74-29 •Soluble organic matters 2'48 3-86 4-27 2-95 2-74 Soluble inorganic matters . . 1-54 2-97 2-86 1-97 1-87 flnsoluble organic matters . . 25-76 18-44 19-23 12-20 10-89 Insoluble mineral matters .. 4 '05 4*90 7-69 7-39 10-21 100-00 100-00 100-00 100-00 100 00 ♦Containing nitrogen . . •149 •27 •30 •19 •18 . Equal to ammonia .. •• •181 '32 •36 •23 •21 tContaining nitrogen .. •494 •47 •59 •47 •47 Equal to ammonia . . . . -599 •57 •71 •62 •57 Total amount of nitrogen . . •643 -74 •89 -66 •65 Equal to ammonia •780 •89 1-07 -85 -78 Ammonia in a free state . . •034 , -019 •008 -010 -006 Ammonia in form of salts, | easily decomposed by> •088 •064 •085 -038 •041 quicklime J u4 1 Total amount of organic matters 28-24 22^30 23-50 15-15 13-63 Total amount of mineral sub- stances , 5*59 7^87 10-55 9-36 12-08 It will be seen that in February this manure contained about 3i per cent, more moisture than when first put up. At the end of April, little or no rain having fallen in the interval, it dried up to its original state of dryness. The loss in weight in April Farmyard Manure. 41 amounting to 286 per cent., therefore, is real loss, that is to say it is loss which affects the dry manure, and is not due to eva-. poration of water. In other words 100 lbs. of dry manure, on keeping for a period of 6 months exposed to the weather, lost 28*6 lbs., and became only 71-4 lbs. In August the manure gained a very large quantity of water, by heavy showers of rain, and this large proportion of water, which is greater than the original quantity of moisture by nearly 10 per cent., was reduced only 1 per cent, on keeping of the manure for another 3 months. The direct- weighings, as well as the composition of the manure, are therefore much affected by the rain that falls at the different periods, and for this reason, neither the analyses nor the weigh- ings by themselves are fit to determine the loss which farmyard- manure undergoes on keeping. Before any further remarks can be offered on these analyses it will be necessary to calculate the composition of the manure in a dry state, for as the percentage of water differs so much at the various times of analysis, the results in the preceding Table are not comparable. In the next Table, therefore, 1 have stated the composition of the perfectly dry manure at various epochs. Composition of Fresh Farmyard Manure (No. I.), Exposed. Calculated Dry. When put up. Nov. 3rd, 1854. Feb. 14th, 1855. April 30th, 1855. Aug. 23rd, 1855. Ncv. 15th, 1855. ♦Soluble organic matters . . Soluble inorganic matters t Insoluble organic matters Insoluble mineral matters 7-33 4-55 76.15 11^97 12-79 9-84 61-12 16-25 12 -.54 8-39 56-49 22-58 12-04 8-03 49-77 30-16 10-65 • 7-27 42-35 39-73 ♦Containing nitrogen Equal to ammonia f Containing nitrogen Equal to ammonia . . . . Total amount of nitrogen Equal to ammonia Ammonia in free state . . Ammonia in form of salts, easily) decomposed by quicklime . . ) Total amount of organic mattere Total amount of mineral sub-" stances / 100-00 •44 •53 1^46 1-77 1-90 2-30 •10 •26 83-48 16-52 100*00 •91 1^10 1-55 1*88 £•46 2-98 •062 •212 73-91 26*09 100-00 -88 1-06 1-75 2-12 2-63 3-18 •023 •249 69-03 30-97 100*00 •77 ;93 1-92 2-33 2-69 3-26 •041 •154 61-81 38*19 100-00 •72 •88 1^85 2*24 2-57 3-12 •023 •159 53-00 47 '00 A comparison of these different analyses points out clearly the changes which fresh farmyard manure undergoes on keeping in a heap, exposed to the influence of the weather during a period of twelve months and twelve days. 42 Farmyard Manure. 1. It will be perceived that the proportion of organic matter steadily diminishes from month to month, until the original per- centage of organic matter in the dry manure, amounting to 83*48 per cent., became reduced to 53 per cent. 2. On the other hand, the total percentage of mineral matters rises as steadily as that of the organic matters falls. 3. It will be seen that the loss in organic matters affects the percentage of insoluble organic matters more than-the percentage of soluble organic substances. 4. The percentage of soluble organic matters indeed increased considerably during the first experimental period ; it rose, namely, from 7*33 per cent, to 12'79 per cent. Examined again on the 30th of April, very nearly the same percentage of soluble organic matters as on February the 14th was found. The August analysis shows but a slight decrease in the percentage of soluble organic matters, whilst there is a decrease of 2 per cent, of soluble organic matters when the November analysis is compared with the February analysis. 5. The soluble mineral matters in this manure rise or fall in the different experimental periods in the same order as the soluble organic matters. Thus, in February, 9*84 per cent, of soluble mineral matters were found, whilst the manure contained only 4'55 per cent., when put up into a heap in November, 1854. Gra- dually, however, the proportion of soluble mineral matters again diminished, and became reduced to 7'27 per cent., on the exa- mination of the manure in November, 1855. . 6. A similar regularity will be observed in the percentage of nitrogen contained in the soluble organic matters. 7. In the insoluble organic matters the percentage of nitrogen regularly increased from November, 1854, up to the 23rd of August, notwithstanding the rapid diminution of the percentage of insoluble organic matters. For the last experimental period the percentage of nitrogen in the insoluble matters is nearly the same as in August 23rd. 8. With respect to the total percentage of nitrogen in the fresh manure, examined at different periods of the year, it wdll be seen that the February manure contains about one-half per cent, more of nitrogen than the manure in a perfectly fresh state. On the 30th of April the percentage of nitrogen again slightly increased ; on August 23rd it remained stationary, and had sunk but very little when last examined on the 15th of November, 1855. This series of analyses thus shows that fresh farmyard manure rapidly becomes more soluble in water, but that this desirable change is realised at the expense of a large proportion of organic matters. It likewise proves in an unmistakable manner that ' there is no advantage in keeping farmyard manure for too long Farmyard Manure. 43 a period ; for after February neither the percentage of soluble organic nor that of soluble mineral matters has become greater ; and the percentage of nitrogen in the manure of April and August is only a very little higher than in February. Weight for weight, the February manure thus will be as good as the manure in April or August, and slightly superior to the manure in November, 1855. The direct weighings, however, of the whole heap have shown us already that a considerable loss in weight is experienced in the different periods during which the manure was kept. And as the fresh manure did not improve in composition after the 14th of February, it is clear that the loss in weight is not due to the mere evaporation of water or the dissipation of other useless constituents, but is a real loss in valuable fertilising constituents. That this is really the case appears still more decidedly if we consult the direct weighings of the experimental heap, and the composition of the manure at the time at which the weighings were made. This will enable us to calculate the composition of the whole heap at the different experimental periods, and we shall then see in what manner the loss in weight is distributed amongst the various constituents of the manure. In the following Table the composition which the whole experimental heap. No. I., exhibited at different periods of the year, has been calculated from data already given. The actual weight of the manure heaps is again stated in the first horizontal column ; in the second horizontal column, the actual amount of water in the whole heap is stated ; and in the third, the total amount of dry matter. The next four (bracketed together) show the composition of the dry matter. All numbers in the Table express pounds or fractions of pounds. A careful study of the Table will convince the reader that the real loss in valuable fertilising matters which farmyard manure sustains in keeping is very much greater than is indicated by the direct weighings of the experimental heap. It will be remembered that the manure, when put up in a heap on the 3rd of November, 1854, contained 66*17 per cent, of water, and con- sequently 33'83 per cent, of dry matters. The total amount of dry matter in the perfectly fresh experimental heap amounted to 960*10 lbs. ; but, after having been exposed to the influence of the weather for a period of nine months, only 488*7 lbs. of dry substance are left behind. The direct weighing of the heap in August indicates a loss of 29*77 per cent., whereas in reality a loss of very nearly 50 per cent, in the solid constituents of the manure has been incurred. This enormous icaste in manur- ing matters, it will appear likewise from a careful perusal of the Table, may be prevented, at least to a very great ex-" 44 Farmyard Manure. tent, by applying either the manure in a fresh state to the land, or, if this is inadmissible, by keeping it no longer than is absolutely necessary. Table showing Composition of the Whole Heap : Fresh Farmyard Manure (No. 1.), Exposed. Expressed in lbs. Weight of manure in lbs Amount of water in the manure . . Amount of diy matter in the manure . Consisting of — •Soluble organic matter Soluble mineral matter t Insoluble organic matters Insoluble niiueral matter ♦Containing nitrogen Equal to ammonia + Containing nitrogen Equal to ammonia Total amount of nitrogen in manure . Equal to ammonia The manure contains ammonia in free state ,, ,, ammonia in form of) salts, easily decomposed by quicklime j" Total amount of organic matters . . Total amount of mineral matters . . When put up. Nov. 3rd, 1854. 2838 1877-9 960-1 70-38 43-71 731-07 114 94 960- 1 4-22 5-12 14'01 17*02 18-23 22- 14 •96 2 49 801*45 158-15 April 30tb, 1855, 2026 1336-1 689-9 86-51 57-88 389-74 155-77 689-9 6*07 7-37 1207 14*65 18-14 22-02 •15 1*71 476*25 213*65 Aug. 23rd, 1855. 1994 1505*3 488-7 58-83 39-16 243-22 147-49 488-7 3 76 4-56 9-38 11*40 13*14 15-96 •20 *75 302*05 186*65 Nov. 15th, 1855. 1974 1466-5 507 5 54-04 36-89 214-92 201-65 507-5 3*65 4-36 9-38 1139 13-03 15*75 •11 •80 268-96 238 -.'54 It will be remarked that in tlie first experimental period the fermentation of the dung, as might have been expected, pro- ceeded most rapidly, but that, notwithstanding, very little nitrogen was dissipated in the form of volatile ammonia ; and that on the whole the loss which the manure sustained was inconsiderable when compared with the enormous waste to which it was subject in the subsequent warmer and more rainy seasons of the year. Thus we find at the end of April very nearly the same amount of nitrogen which is contained in the fresh ; whereas, at the end of August, 27*9 per cent, of the total amount of nitrogen, or nearly one-third of the nitrogen in the manure, has been wasted in one way or the other. It is worthy of observation that, during a well-regulated fer- mentation of dung, the loss in intrinsically valuable constituents is inconsiderable, and that in such a preparatory process the efficacy of the manure becomes greatly enhanced. For certain purposes fresh dung can never take the place of well-rotten dung. Farmyard Manure. 45 The farmer will, therefore, always be compelled to submit a portion of home-made dung to fermentation, and will find satis- faction in knowing that this process, when well regulated, is not attended with any serious depreciation of the value of the manure. In the foregoing analyses he will find the direct proof that, as long as heavy showers of rain are excluded from manure heaps, or the manure is kept in waterproof pits, the most valuable fer- tilising matters are preserved. But let us now see how matters stand when manure heaps, the component parts of which have become much more soluble than they were originally, are exposed to heavy showers of rain. In the first experimental period little rain fell, and this never in large quantities at a time, whilst in the interval of April and August rain was more abundant, and fell several times in con- tinuous heavy showers. In consequence of this the soluble matters in the heap have been washed out, and with them a con- siderable portion of available nitrogen, and the more valuable mineral constituents of dung have been wasted. The above analytical data, if I am not mistaken, afford like- wise a proof that even in active fermentation of dung little nitrogen escapes in the form of volatile ammonia, but that this most valuable of all fertilising materials, along with others of much agricultural importance, is washed out in considerable quantities by the rain which falls on the heaps and is wasted chiefly in the drainings of the dungheaps. A single fact, it has been truly said, is worth more than a dozen vague speculations. We hear frequently people talk of the loss in ammonia which farmyard manure undergoes on keeping, and this loss is referred by them to the volatilization of the ammonia which is produced in the putrefaction of the nitrogenized con- stituents of dung. I have, however, already mentioned that simultaneously with the ammonia, ulmic, humic, and other organic acids are generated from the non -nitrogenized consti- tuents of manure, and that these acids possess the power of fixing the ammonia in an excellent manner. If this werq not the case it would be difficult, if not impossible, to explain the circumstance that the proportion of soluble nitrogenized matters increased considerably in the manure on keeping for a period of six months, and that during this period the total amount of nitrogen scarcely suffered any diminution. In April the amount of nitrogen in the soluble matters of the entire heap is 6'07 lbs., and by the 23rd of August it is reduced to 3'76 ll?s. Why, it may be asked, is it not likely that most of this nitrogen has passed into the air in the form of volatile ammoniacal compounds? In reply to tliis question I would answer tliat a loss taking place in this way would be felt 4d Farmyard Manure. much more sensibly in the period of active fermentation, in which, however, we have seen that scarcely any nitrogen is dis- sipated. In the August and November analyses, moreover, it will be observed that not only the amount of soluble organic matters, and with it that of the nitrogen, decreases, but that the soluble mineral matters, which in April amount to 57*88 lbs. in the entire heap, became reduced to 39*16 lbs. by the 23rd of August. Now, this decrease in soluble mineral substances can only be ascribed to the rain which fell in this period, and it is plain that the deteriorating influence of heavy showers of rain must equally affect the soluble nitrogenized constituents of dung. That this is really the case will appear still more conspicuously by the analysis of experimental heap No. 111., to be mentioned hereafter. It may perhaps appear strange to the reader that the total amount of dry matter in the manure is greater in November, 1855, than in August, and likewise that there is a good deal more insoluble mineral matter at the end of the experimental year than at the beginning. In explanation of these apparent inconsistencies, I would observe that the increase in insoluble mineral matters is accounted for in the difficulty of shovelling the manure into the dung-cart without mixing with it each time the weighing is made a certain portion of the soil on which the heap is placed. It must likewise be borne in mind that it is almost next to impossible to incorporate mechanical impurities so thoroughly with the dung that differences amounting to 2 or 3 per cent, in the amount of insoluble matters may not occur in the analyses of 2 samples taken from the same heap. In the percentic composition of farmyard manure such differences ap- pear inconsiderable, but when applied to the whole heap they strike us as being great. In short, it is impossible to determine accurately the total amount of insoluble mineral matters in the whole heap. The general deductions, however, which may legitimately be made from the foregoing analyses are not in any perceptible degree affected by this unavoidable source of inac- curacy ; but it is well to remember not to dwell too much on minor differences which perhaps may strike the reader ; some such differences may be due to purely accidental causes. Before I pass over to the experimental heap No. II., I would direct attention to the subjoined Table, in which I have calcu- lated the loss or gain which the experimental heap No. I. sus- tained in the different constituents in the course of the year. Where there is a gain the sign * is prefixed to the number to which it applies ; all numbers without this sign express loss in lbs. and in fractions of lbs. The loss for the whole heap has been calculated for 100 lbs. of fresh manure, as well as per ton. Farmyard Manure. 47 In the columns headed per cent, thus may be seen how much of each of the constituents of fresh dung is lost by 100 lbs., cwts., or tons, in the course of 6, 9, or 12 months ; whilst the columns headed loss per ton, give the loss in lbs. for every ton of fresh farmyard manure. ■Table showing Loss in the different constituents of Experimental Heap, No. I., at different m Periods of the Year ; likewise Percentage of Loss and Loss per Ton of Fresh Manure. ■' (N.B. The numbers preceded by the sign * express Gain and not Loss.) 1 T^ss in weight of — Entire heap Water Soluble organic matter . . Soluble mineral matter . . . Insoluble organic matter Insoluble mineral matter . . Containing nitrogen .... Equal to ammonia .... Containing nitrogen .... Equal to ammonia .... Total amount of nitrogen . . Equal to ammonia .... Ammonia in free state . . . Ammonia in form of salts . From November 3, 1854, To April 30. 1855. Kept 6 Months. To August 23, 1855. Kept 9 Months. To November 15, 1855. Kept 12 Months. 812- 641-8 Per cent, 28 61 19-09 Per ton. 640-86 427-61 844^ 372-6 Per cent. 29-77 13-12 Per ton. 666^84 239-88 864- 411-4 Per cent, 30-45 14-49 Per ton. 682-07 324-57 *16-13 *14-17 341-33 *40-83 *-56 *-49 12-03 *l-43 *12-54 *10-97 269-47 *32-03 11-45 4-55 487-85 *32-55 -40 •16 17^18 *i-i4 8-96 3-58 384-83 *25-53 16-34 6-82 516^15 *86- 71 •57 •24 18-17 •3-05 12-76 5-37 407-00 *68-32 *l-85 *2-25 1-94 2-37 *-065 *-079 •068 •083 *l-456 *l-769 1-523 1-859 •46 •56 4-63 5-62 •016 •019 •160 -19 •358 -425 3-58 4-25 •57 •76 4^63 5-63 •020 •026 •160 •19 •448 •582 3-584 4-25 -09 -12 •003 •004 •067 -089 5-09 6-18 1-79 •21 4-099 4 70 5^20 6-39 •18 -22 4^03 4-92 •81 •78 •028 •027 -627 •604 -76 1-74 -026 •06 •582 1^34 8^5 1-69 •029 -059 •649 1-321 Total amount of organic matter Total amount of mineral matter 325-20 *55-00 11-45 '256-48 *l-92 .*43-00 1 499-40 *28-00 17-59 *^99 394^01 *:21-95 532-49 •79-89 18-76 *2-8l 420-22 *62-94 Experimental Heap (No. II.), Fresh Farmyard Manure under Shed. — Horse, cow, and pig dung mixed. The direct weighings were made on the same days on which the weighings of the heap exposed to the influence of the weather were executed. The following Table contains the results of these weighings : — Table showing the actual Weighings, and Percentage of Loss in Weight, of Experimental Heap (No. II.), fresh Farmyard Manure under Shed, at different periods of the Year. Put up on the 3rd of November, 1854 Weighed on the 30th of April, 1855, or after 'i a lapse of ti months / Weighed on the 23rd of August, 1855, or) after a lapse of 9 months and 20 days . . f Weighed on the 15th of November, 1855, or) after a lapse of 12 mouths and 12 days . . ) 48 Farmyard Manure. Apparently the loss which the heap under shed sustained is much greater than the loss which was incurred by keej)ing a heap of fresh farmyard manure exposed to the influence of the weather for the same length of time. It will be seen, however, by the following analyses, that this greater loss is principally due to the evaporation of water, which, not being replaced by falling rain, is especially marked in the warmer months of the year. This will appear from the following Table, containing the results of analyses made at the fixed experimental periods. Table showing the Composition of Experimental Heap (No. II ), fresh Farm- yard Manure under Shed, in natural state, at different periods of the Year. Water *Soluble organic matters . . Soluble inorganic matters t Insoluble organic matters Insoluble mineral matters ♦Containing nitrogen Equal to ammonia tContaining nitrogen Equal to ammonia Total amount of nitrogen Equal to ammonia Ammonia in free state . . Ammonia in form of salts, easily "1 decomposed by quicklime . . j Total amount of organic matters Total amount of mineral sub-1 stances / When put up. Nov, 3rd, 1854. 66*17 2-48 1'54 25-76 4-05 100-00 Feb. 14th, i April 30th, 1855. 1855. 67 '32 2-63 212 20*46 7-47 56-89 4-63 3-38 25*43 9*67 100*00 100-00 -27 •32 '92 '11 •19 •43 055 •149 -17 i •181 •20 •494 •58 ! •599 •70 1 •643 •75 i •780 •90 1 •034 •022 •088 •054 28^24 23-09 5-59 9 59 •101 30 06 13'05 Aug, 23rd, 43-43 4-13 3-05 26'01 23-38 100-00 •26 •31 1 01 1-23 P27 1^54 •015 •103 30^14 26^43 Nov. 15th, 1855. 41-66 5-37 4-43 27-69 20-85 100-00 •42 •51 1^09 1^31 1 51 \-%2 •019 .146 33-06 25-28 As these analytical results do not admit of comparison on ac- count of the great variations in the amount of moisture contained in this manure at different periods, the comj)osition of the manure in a perfectly dry state may at once be stated. (See Table, p. 49.) These analytical results give rise to the following obser- vations : — 1. It will be seen that the percentage of organic matter in this manure steadily diminishes the longer the manure is kept, whilst the percentage of mineral matters rises in a corresponding degree. 2. The decrease in organic substances, however, is much less considerable than in the heap No. I., which had been exposed to the influence of the weather. 3. It will likewise be observed that the percentage of soluble Farmyard Manure. 49 Table showing the Composition of Experimental Heap (No. TI.), fresh Farm- yard Manure under Shed, calculated dry, at different periods of the Year. ♦Soluble organic matters .. Soluble inorganic matters flnsolnble organic matters Insoluble mineral matters ♦Containing nitrogen Equal to ammonia fContaining nitrogen Equal to ammonia Total amount of nitrogen Equal to ammonia Ammonia in free state . . Ammonia in form of salts, easily ) decomposed by quicklime . . j Total amount of organic matters Total amount of mineral sub-l stances / When put up. Nov. 3rd, 1854. 7*33 4-55 76-15 11-97 100-00 •44 •53 1-46 1-77 1-90 2-30 •10 -26 83-48 16-52 Feb. 14th, 1855. 8-04 6-48 62-60 22-88 100-00 •53 •66 1-77 2'14 2-30 2-80 •067 •165 70-64 29-36 April 30th, Aug. 23rd, 1855. I 1855. 10-74 I 7^30 7-84 I 5-39 58-99 I 45*97 22 43 I 41-34 100-00 ,100-00 •63 •76 2^14 2^59 2'77 3^35 -127 •234 69-73 30-27 ■46 -56 1-78 2-16 2-24 2-72 •026 •182 53^27 46*73 Nov. 15th, 1855. 9-20 7 59 47-46 35-75 1 00*00 •72 -88 1-88 2 20 2-60 3-08 •032 •250 56-66 43-34 organic and mineral substances increases, up to the SOth of April, with the time during which tiie heap has been kept under shed ; but that this increase is not so great as in the experimental heap No. I. 4. The proportion of free ammonia, and of ammonia contained in salts which are readily decomposed by quicklime, perceptibly decreases on keeping of the manure. 5. The total amount of nitrogen, on the contrary, perceptibly increases in the several experimental periods. 6. The amount of nitrogen in the soluble organic matters slightly, but regularly, increases with the time during which the manure is kept ; and the same remark applies to the nitrogen in the insoluble organic matters. 7. The August analysis exhibits a very much larger percent- age of insoluble inorganic substances than the April analysis, and even than the analysis made on the 15th of November, 1855. It is evident that the sample taken for analysis on the 23rd of August contained a considerable amount of mechanical impuri- ties, which spoil, to some extent, the general results. In a minor degree this source of error will be perceived in the November analysis (November 15th, 1855). If, however, due allowance be made for this evident admixture of accidental earthy matters, 50 Farmyard Manure. the analysis made in August and in November, 1855, will be found to correspond perfectly in their general bearings with the other analyses. Having obtained the results by carefully exe- cuted analyses, I did not feel justified in introducing corrections, even in case such corrections seemed desirable to be made. A critical mind will derive from the two last analyses as much instruction as from the three preceding. They afford, at the same time, a direct proof of the necessity of not being satisfied with one or two analyses in researches of this kind, and show that trustworthy deductions can be derived only from a series of carefully conducted analyses. It is too often the case that cor- rections are introduced into analyses which cannot always be referred to plain and evident disturbing causes ; and as such a course, if tolerated, opens at once the door to abuse, I have ever set my face against such a practice, and therefore prefer to state my results as I get them, whether or not they agree with others. The preceding analyses furnish plain evidence that the consti- tuents of the manure under shed have become far less altered in composition than in the case of the experimental heap No. II. And, indeed, the physical condition of the heap under shed affords a convincing proof of the fact that fresh farmyard manure does not properly ferment when it is kept under cover, and the water, which constantly evaporates from its surface, is not replaced by pumping occasionally water or liquid manure over the heap. The fermentation, however, of the dung cannot be entirely prevented by this mode of treatment As might have been expected, fermentation is more perceptible in the first experi- mental periods than in the succeeding. By the time the per- centage of water in this manure had become reduced to 56 per cent., practically speaking a stop was put to further fermenta- tion, and the manure remained very much in the same condition, at the end of the experimental year, in which it was found at the end of April. In the next Table the composition of the whole heap under shed, as calculated from the preceding analyses, is given (p. 51). A reference to the Table will show that the loss incurred in keeping of fresh farmyard manure under cover is greatest in the first experimental period, and that this loss principally affects the insoluble organic matter. Thus, when put under cover, the whole heap contained, in round numbers, 839 lbs. of insoluble organic substances, whilst after a lapse of six months only 410 lbs. were left over. One half of the total amount of insoluble organic matters thus has been dissipated, in the form of carbonic acid and other gaseous products of decomposition, in the course Farmyard Manure. 51 Tabic showing Composition of entire Experimental Heap (No. II.), fresh Farmyard Manure, under Shed. • When put up. Nov. 3rd, 1854. April 30th, 1855 Aug. 23rd, Nov. 15th, 1855. 1855. Weight of manure 3258 1613 1297 1235 Amount of water in the manure . . Amount of dry matter Consisting of — ♦Soluble organic matter Soluble mineral matter flnsoluble organic matter Insoluble mineral matter 2156' 1102- 80-77 50-14 839-17 131*92 917-6 695-4 74-68 54-51 410-24 155-97 563-2 514-5 733-8 720-5 53 -.56 66*28 39-55 54-68 337-32 341-97 303-37 257-57 1102- 695-4 733-8 720-5 ♦Containing nitrogen Equal to ammonia 4-85 5-88 ie-08 19-52 4-38 5-33 14-88 17-46 3.46 5.25 4-20 6-37 fContaining nitrogen Equal to ammonia .* . . 13-08 13-54 15-88 16-44 Total amount of nitrogen in manure . . Equal to ammonia 20-93 25-40 19-26 22-79 16-54 18-79 20-08 22-81 The manure contains ammonia in free state , , , , ammonia in form of\ salts, easily decomposed by quicklime , Total amount of organic matters . . . . Total amount of mineral matters . . 1-10 2-86 919-94 182-06 •88 1-62 484-92 210-48 -19 -23 1-33 1-80 390-88 408-25 342-92 312-35 of six months. Or, calculating the loss in dry matter, for the whole manure-heap in a dry state, we find that 100 parts of the dry manure have lost, under cover, about 37 per cent, in solid matters. The dissipation of organic matter is not attended with any great loss in nitrogen, for it will be observed that the entire heap contained in November, 1854, when first put up, 20*93 lbs. of nitrogen, and on the 30th of April, 19*26 lbs.; consequently, about 1^ lb. of nitrogen only escaped, in one way or the other, during this period. It would appear that this inconsiderable amount of nitrogen escaped by evaporation, in the form of volatile carbonate of ammonia ; for the differences exhibited by the November and April analyses, in the proportion of free ammonia and ammonia in form of salts readily decomposed by quicklime, very nearly correspond with a loss of about 1^ lb. of nitrogen. Perhaps it may appear strange that the manure-heap No. I., which was exposed to the weather, lost less nitrogen, in the form of ammonia, during the first six months than the heap under cover. But this apparent anomaly finds a ready explana- 52 Farmyard Manure. tion in the fact that during an active fermentation organic acids are formed which fix the ammonia, while the same acids are not so readily produced in the absence of the requisite amount of moisture. At the same time it should be borne in mind that ammonia escapes more readily from a partially-dried substance than one saturated with moisture; and as the manure- heap under shed on keeping became much drier than the heap exposed to the weather, the free ammonia had a better chance of being dissipated into the air. The August and November, 1855, analyses on account pf the accidental impurities, do not give a fair representation of the changes which may have taken place during these periods. There should be of course the same total amount of mineral matters at the end of the experimental year which occurs in the manure when first placed under cover. Omitting the fractions we have in November, 1855, 182 lbs. of mineral matters, and on the 30th of April, 210 lbs., or a difference which is not greater than might have been expected in two analyses of the same sample of manure. But assuming the samples, which have been taken for tlie August and November analyses, to represent fairly the composi- tion of the whole heap, we would have no less than 343 lbs. of mineral matters in August, and 312 lbs. the following November. Now this cannot be the case, and it is therefore plain that the excess of mineral matters must be due to accidental admixture of dirt to the dung. Such an admixture of course will reduce the amount of nitrogen and organic matters in the analyses : but if a correction be made for this palpable inaccuracy it will be found that after the 30th of April the heap under shed sustained but a very trifling loss in nitrogen and organic matters. Leaving the reader to make this calculation for himself, I append a Table which will furnish the data for similar calcu- lations (p. 53). Experimental Heap (No. III.), fresh Farmyard Manure, spread in an open Yard. — Mixed horse, cow, and pig dung. Having furnished the reader with a complete analysis of each experimental heap with the exception of the manure spread out in an open yard, I thought it desirable to submit the manure No. III., the originally fresh farmyard manure, to a complete organic and inorganic analysis, after it had been exposed to the influence of rain, sun, and wind for a period of six months. The results of this examination are incorporated in the following Tables. Farmyard Manure. u Table showing Loss in the different component parts of Experimental Heap, No. II., at different periods of the Year ; likewise Percentage of Loss and Loss per Ton of Fresh Manure. (N.B. The numbers preceded by the sign * express Gain instead of Loss.) From November 3, 1864, To April 30, 1855. ' Kept 6 Months. To August 23, 1855. Kept 9 Months. November 15, 1855. Kept 12 Months. Loss in weight of— Entire heap Water 1645- 1238-4 Percent. 50-49 38- Per ton. 1130-97 851-20 1961- 1592-8 Percent. 60-19 48-88 Per ton. 1348-25 1094-91 2023* 1641-5 Percent. 62-09 60-35 Per ton. 1390-81 1127-84 ♦Soluble organic matter . . . Soluble mineral matter . . flnsoluble organic matter . . Insoluble mineral matter . 6-09 *4-37 428-93 *24-05 -18 *-13 13-16 *-73 4-03 *2-91 294-78 *16-35 27-21 10-59 501-85 *171-45 •83 •32 15^40 •5-26 18-59 7-16 344-96 *1 17-82 14-46 *4-54 497-2 *125-65 -44 •-14 15-26 •3-85 9-85 *3^13 341-82 •86-24 ♦Containing nitrogen . . . Equal to ammonia .... •fOontaining nitrogen . . . Equal to ammonia .... -47 •55 1-20 2-06 •014 -016 -036 ■053 •31 •35 80 1-41 1-39 1-68 3-00 3-64 •042 •051 -092 •HI •94 1-14 2*06 2-48 •-40 *-49 2-54 3-08 •-012 ••015 •078 •094 •-26 •35 1-74 2-10 Total amount of nitrogen . . Equal to ammonia .... 1-67 2-61 -051 •080 1-14 1-79 4-39 5-32 •134 •163 3-00 3-65 2-14 259 -065 •079 1-45 1-76 Ammonia in free state . . . Ditto in form of salts . . . -22 1-24 -006 -03 •13 •67 -91 1-53 •027 -046 -60 1-03 •87 1-06 •026 •032 •58 •71 Total amount of organic matter Ditto mineral matter . . . 435-02 •28-42 13-34 *86 298-81 *19-25 529-06 *160-86 16-23 *4-94 363-55 *ll0-66 511-69 •130-19 15-70 •3-99 351-67 •89-37 Fresh Farmyard Manure (No. III.), Spread in open Yard. Taken for Analysis, April 30, 1855. (a.) Composition of Manure in Natural State. Water 80*02 * Soluble organic matter 1*16 Soluble inorganic matter (ash) : — Soluble silica . •211 Phosphate of lime '194 Lime '005 Magnesia *008 Potash -365 Soda -037 Chloride of sodium '004 Sulphuric acid '041 Carbonic acid and loss '145 1-01 t Insoluble organic matter 11*46 Insoluble inorganic matter : — Soluble silica '955 Insoluble silicious matter 1*101 Oxide of iron and alumina, with phosphates . . '622 Containing phosphoric acid ("ITT) Equal to ijone earth ('276) Carry forward . . . . 93*65 F 54 Farmyard Manure. "'""'"' Brought forward .. .. 93'65 LiMe 1-964 Magnesia '082 Potash -052 Soda -009 Sulphuric acid '. '066 Carbooic acid and loss 1*499 6-35 100-00 * Containing nitrogen .. .. *68 Equal to ammonia '09 t Containing nitrogen '45 Equal to ammonia '54 Whole manure contains amm. in free state per cent. '010 „ „ in form of salts '045 (5.) Composition of the same Mcmiure in dry state. * Soluble organic matter 5*80 Soluble inorganic matter (ash) : — Soluble silica 1*05 Phosphate of lime 1*07 Lime '02 Magnesia '04 Potash 1-82 Soda -18 Chloride of sodium '02 Sulphuric acid '20 Carbonic acid and loss "65 5-05 ff Insoluble organic matter 57*37 Insoluble inorganic matter (ash) : — Soluble silica 4*78 Insoluble silica 5*51 Oxide of iron and alumina, with phosphates . . 3*11 Containing phosphoric acid ('89) Equal to bone earth (1*00) Lime 9*83 Magnesia *41 Potash .. -27 Soda .. -06 Sulphuric acid '33 Carbonic acid and loss 7*48 31*78 100-00 * Containing nitrogen '42 Equal to ammonia '51 f Containing nitrogen 2*28 Equal to ammonia 2*76 Whole manure contains amm. in free state per ct. '05 ^ „ in form of salts .. "225 Farmyard Manure. 56 ( c.) Composition of Ash ofp(yrtion insdiMe in Water. Soluble silica 15*05 Insoluble silicious matter (sand) 17'35 Oxides of iron and alumina, with phosphates 9'80 Containing phosphoric acid (2*80) Equal to bone earth (4*36) Lime 30*94 Magnesia 1'30 Potash .. .. -87 Soda '02 Sulphuric acid 1*05 Carbonic acid and loss 23*62 100*00 Composition of Ash of portion sduUe in Water. Soluble silica ., 20*93 Phosphate of lime 19*29 Lime '50 Magnesia -82 Potash 36*21 Soda 3*69 Chloride of sodium '41 Sulphuric acid 4*10 Carbonic acid and loss 14*05 1 ■4J ^ t-t ^d k\ « CO ,o pi CO 02 100*00 No, JV. spread out. Taken for Analysis, April 39, 1855. Composition of mixed Ash. Soluble silica 2*87 Phosphate of lime 2*64 Lime -06 Magnesia '11 Potash 4*97 Soda '50 Chloride of sodium '05 Sulphuric acid '50 Carbonic acid and loss 2*03 Arranged together. Soluble silica .. 13*05 15*90 Insoluble silica 14*96 14*96 Phosphate of lime *.. 2*64 Oxides ofiron and alumina with phosphates 8*45 8*45 Containing phosphoric acid (2*41) (2*41) Equal to bone earth (3*76) (3*76) Lime 26*69 26*75 Magnesia 1'12 1*23 Potash -75 5-72 Chloride of sodium -05 Soda -02 -52 Sulphuric acid -90 1*40 Carbonic acid and loss 2035 22*38 100-00 100-00 jf2 56 Farmyard Manure. Leaving any remarks on the organic composition of the manure until the general composition at the different experimental periods has been stated, I shall offer in this place merely a few observa- tions on the differences which w^ill be perceived on comparing the ash analyses of the fresh manure with those that have just been given. 1. In the first. place it will be seen that the proportion of soluble fresh ash is v«ry much greater in the manure, when the experiment was taken in hand on the 3rd of November, than after a lapse of 6 months, during which the manure was spread out in an open y.ird and exposed to the deteriorating influence of the weather. Thus we find — In fresh Manure, The same Manure, analysed Nov. 3, 1855. analysed April 30, 1855. Soluble ash .. .. .. 27*55 13-73 Insoluble ash .. ..... 72-45 86-27 100-00 100-00 We have thus here a clear proof that the rain which falls on the manure kept in an open yard, rapidly deteriorates its value by removing from it a very considerable proportion of the most valuable saline constituents. 2. On comparing the insoluble ash of the fresh manure with the. corresponding portion of the ash of the manure after having been exposed in an open yard to the weather, it will be seen that there is a much larger proportion of insoluble silicious matter in the April analysis, but less potash and only about half the amount of phosphate of lime which is contained in the insoluble ash of the same manure before it had been spread out in an open yard. 3. The soluble portion of the ash of this manure in April con- tains, it will be seen, more soluble silica and sulphuric acid than the soluble ash of the manure in November, 1855. 4. The influence of rain on manure spread out in an open yard is best seen by comparing the composition of the whole ash of the manure, analysed in April, with the analysis of the whole ash of the manure in a perfectly fresh state. In the whole ash of the April manure is less soluble silica, less potash, and much less phosphate of lime, than in the ash of the manure in a fresh state. The most soluble, and at the same time most valuable fertilizing substances thus are washed out by falling rain, and consequently an ash richer in lime and insoluble matters is left on burning the manure on the 30th of April. The actual loss in weight which this experimental heap sustained in the year, is given in the following Table. Fai-mi/ard Manure. 57 Tabic showing the actual Loss in Weight, and Percentage of Loss in Weight, of Experimental Heap (No. IIL), fresh Farmyard Manure, spread, at different periods of the Year. Put up on the 3rd of November, 1854 . . Weighed on the 30th of April, 1855, or after) a lapse of 6 months j Weighed on the 23rd of August, 1855, or) after a lapse of 9 months and 20 days . . j Weighed on the 15th of November, 1855; after a lapse of 12 months and 12 days orl The loss in weight on the 30th of April, thus amounted to only 13 J per cent. ; but as rain had fallen shortly before the weighing was made in April, the real loss in valuable fertilizing matters is much greater than indicated by the direct weighing. This will appear clearly when the composition of the entire quantity of the manure spread in the open yard shall have been stated. Before doing this, however, I shall endeavour to explain the alterations which the spread manure underwent in the course of the experimental year. The third series of analyses, incorporated in the subjoined Table, I trust will afford a sure guide in drawing satisfactory conclusions. Table showing Composition of Experimental Heap (No. IH.), fresh Farm- yard Manure, spread in open yard, at different periods of the Year. In natural state. When put up. Nov. 3rd, 1854. April 30th, 1855. Aug. 23rd, 1855. Nov. 15th^ 1855. Water ♦Soluble organic matters Soluble inorganic matters t Insoluble organic matters Insoluble mineral matters ♦Containing nitrogen Equal to ammonia fContaining nitrogen Equal to ammonia Total amount of nitrogen Equal to ammonia Ammonia in free state Ammonia in form of salts, easily decom- 1 posed by quicklime . . j Total amount of organic matters . . Total amount of mineral substances 66-17 2-48 1-54 25*76 4*05 80-02 1-16 roi 11-46 6-35 70-09 •49 •64 10 -.56 18-22 65-56 •42 •57 9-94 23-51 100-00 •149 •181 •494 •599 •643 •780 •034 •088 28*24 5^59 100-00 •08 •09 •45 •54 •53 •63 •010 •045 12-62 7-36 100-00 •06 •07 -35 •42 •41 •49 •012 •051 ir05 18^86 100-00 •03 •036 -36 •46 •39 •496 •0006 •030 10^36 24-08 58 Farmyard Manure, It will be observed that this manure contained, on the 30th of April, 14 per cent, more water than when first spread out in the yard. The fact was, that a day before it was analysed and weighed, a good deal of rain had fallen, which of course tho- roughly drenched the manure spread about in the yard, whilst it did not thoroughly saturate with moisture the experimental heap No. I. There is thus less moisture in the heap No. I. than in the manure spread out. By the 23rd of August a great deal of moisture had evapo- rated, and on the 15th of November very nearly the same pro- portion of moisture was found which the manure originally c on- tained. We can therefore compare the first with the last analysis without committing any great error, and shall find, on such a comparison, the following interesting particulars : — 1. At the end of the experiment the manure contained, instead of 2h per cent., not quite h per cent, of soluble organic matters. 2. The insoluble organic matters in the course of the year became reduced from 25 * 7 per cent, to 10 per cent. 3. The soluble nitrogenized constituents appear to have been washed out almost completely, since at the conclusion of the experiment the manure contained only '03 per cent., or a mere trace of nitrogen. 4. The total percentage of nitrogen in the manure has become considerably diminished in the manure analysed in November, 1855. The fertilizing value of the manure spread out in an open yard thus became deteriorated by keeping far more considerably than any other of the experimental heaps. Before offering any further remarks on the experiments with this manure, a Table (p. 59) stating the composition, of the manure in a dry state may find here a convenient place. The analytical data incorporated in this Table are extremely interesting and practically important, inasmuch as they show to what extent farmyard manure may become deteriorated in value by slovenly practice, and how rapidly the most valuable fer- tilizing constituents are removed by the rain which falls upon the manure. It will be perceived that the loss in valuable substances is especially great in the warmer months of the year, but I believe it is not so much due to the more elevated temperature that the manure becomes deteriorated, as to the heavy showers of rain which fall in the summer months. On comparing the amount of the different constituents of the manure in the various experimental periods, it will be observed that all the manuring constituents, with the exception of the in- soluble mineral matters, rapidly diminish, so that at last but a Farmyard Manure, 59 Table showing Composition of Experimental Heap (No. III.), fresh Farmyard Manure, spread, at diiferent periods of the Year. Calculated dry. When put up. Nov. 3rd, 1854. April 30th,' Aug. 23rd, 1855. 1855. Nov. 15th, 1855. ♦Soluble organic matters Soluble inorganic matters t Insoluble organic matters Insoluble mineral matters ♦Containing nitrogen Equal to ammonia t Containing nitrogen Equal to ammonia Total amount of nitrogen Equal to ammonia . Ammonia in free state Ammonia in form of salts, easily decom-) posed by quicklime J Total amount of organic matters . . Total amount of mineral substances 7'33 4'55 76'15 11'97 5'80 5*05 57'37 31-78 1-64 2-14 35-30 60-92 1-21 1-69 28 -86 68-24 100-00 •44 •63 1-46 1-77 1-90 2-30 •10 •26 83-48 16 •.'52 100-00 •42 '51 •28 •76 •70 •27 '05 •225 63-17 36-83 100 '00 •20 •24 1-17 1-41 1-37 1^65 •040 •171 36-94 63-06 100-00 •10 •12 1-09 1-32 1^19 1»44 •0017 •087 30-07 69-93 small proportion of the original fertilizing matters is left behind. Thus the soluble organic matters sink from 7*33 per cent, to 58 per cent, in the course of six months, to 1*64 per cent, in nine months, and to 1*21 per cent, in twelve months. With this loss in soluble organic matters the percentage of nitrogen, present in the form of soluble compounds, gradually sinks from '44 per cent, to *10 per cent. That this loss in nitrogen is not entirely due to the evaporation of ammonia, is shown by the simultaneous diminution of the amount of soluble inorganic matters, which became reduced from 4*55 per cent, to 1*69. Still more conspicuous is the loss in insoluble organic matters. Thus we have in the fresh dry manure 76'15 per cent, of insoluble organic matters. After a lapse of six months only 57*37 per cent, are left behind ; after nine months but 35*3 per cent., and after twelve months merely 28*86 per cent. Similar striking differences in the composition of the manure at the stated periods will manifest themselves on an attentive perusal of the foregoing tabulated analytical results. They all tend to prove the enormous waste which is incurred by keeping for a lengthy period farmyard manure exposed in thin layers to the influence of the weather. But I must hasten to ascertain the precise loss in the various constituents which this manure sus- tained in the course of a year. This loss will become apparent by an inspection of the fol- 60 Farmyard Manure. lowing Table, in which is stated the composition of the entire mass of the experimental manure No. III. Table showing Composition of entire mass of Experimental Manure (No. III.), fresh Farmyard Manure, spread. In Natural State. Expressed in lbs. and fractions of lbs. When put up. Nov. 3rdi 1854. April 50th, 185&. Aug. 23rd, 18&5. Nov. 15th, 1855. Weight of manure 1652- 1429- 1012- 950- Amount of water in the manure Amount of dry matter . . Consisting of— ♦Soluble organic matter . . Soluble mineral matter . . t Insoluble organic matter Insoluble mineral matter •Containing nitrogen Equal to ammonia . fContaining nitrogen Equal to ammonia . 1093- 559* 40*97 25*43 425*67 66*93 1143* 285-5 16*55 14-41 163*79 90*75 709*3 302-7 4-96 6-47 106-81 184-46 622*8 327* a 3 95 5*52 94-45 223-28 559*00 285*50 302*70 327*20 3*28 3*98 6*21 7*54 1*19 1*44 6*51 7*90 *60 *73 3»54 4*29 *32 *39 3-56 4*25 Total amount of nitrogen in manure Equal to ammonia 9*49 11*52 7*70 9*34 4*14 5-02 3*88 4-64 The manure contains ammonia in free state , , , , ammonia in form of) salts, easily decomposed by quicklime / Total amount of organic matters . . Total amount of mineral matters .. •55 1*45 466*64 92*36 •14 *62 180*34 105*16 13 111*77 190*93 •0055 •28 98*40 228*80 This Table requires an explanatory notice. It will be observed that the amount of insoluble mineral matters in the manure increases greatly in every succeeding experimental period. Espe- cially it is great in November, 1855- This increase is due entirely to accidental admixtures of earthy matters, which could not be excluded without losing some of the manure. It was found, namely, impossible to collect the manure properly without mixing with it some of the soil over which it was spread. On the 23rd of August, 1855, the manure had shrunk to a very small bulk, and on the 15th of Novenvber, 1855, the greater portion of the manure appeared to have gone either into the air or to have been washed into the soil. It was necessary therefore to scrape the soil as close as possible in order not to lose any of the manure, and it is due to this circumstance that at the conclusion of the experiment a very much larger proportion of insoluble mineral substances was found than in the perfectly fresh manure. I may mention, however, that the whole mass of the spread manure has Farmyard Manure. 61 been most carefully mixed before a sample was taken for analysis. The earthy matters I have every reason to believe were inti- mately mixed with the manure ; and since the composition of the entire mass has been calculated from the data already fur- nished, the general deductions which may be derived from my experiments are not affected by this circumstance. In speaking of the loss which this manure sustained in keeping, I will select the more important fertilizing constituents for illustration, and in reference to them beg to make the following observations : — 1. The weight of the whole manure, when spread out in an enclosed yard, amounted to 1652 lbs. In this quantity were present 40*97, or nearly 41 lbs. of soluble organic matters. After the lapse of six months only 16 5^ lbs. were left in the manure ; in nine months barely 5 lbs., and after twelve months merely 4 lbs. Thus only about 1-lOth part of the original quantity of soluble org^anic matters was left over by keeping fresh farmyard manure spread out in an open yard. 2. The nitrogen contained in the 41 lbs. of soluble organic matters amounted to 3*28 lbs. After six months only 1*19 lbs. of nitrogen, in the state of soluble compounds, was left ; after nine months little more than h lb., and after twelve months only \ of a lb. In other words, the nitrogen in the state of soluble com- pounds has disappeared almost entirely in the course of a year. 3. In an equally considerable degree the soluble mineral mat- ters were dissipated in the manure. Originally the manure contained 25'43 lbs. of soluble mineral matters. After six months this quantity became reduced to 14*41 lbs. ; after nine months to to 6*47 lbs., and after a lapse of twelve months to 5*52 lbs. On the whole the manure thus lost 78*2 per cent, of the ori- ginal quantity of soluble mineral matters. 4. Still more striking is the loss in insoluble organic matters. In the fresh manure were present 425*67 lbs. of insoluble organic substances. In the course of six months these became reduced to 163*79 lbs. ; a further exposure of rather more than three months to the weather reduced this quantity to 106*81 lbs., and after twelve months merely 94*45 lbs. were left over. The manure lost thus no less than 77*7 per cent, of the original quantity of insoluble organic matters. 5. If we look to the total amount of nitrogen, we shall find that tlie original proportion of nitrogen in the manure, amounting to 9*49 lbs., was reduced in the course of six months to 7*70 lbs., after nine months to 4*14 lbs., and after twelve months to 3-88 lbs. At the conclusion of the experiment more than half the quan- tity, or, in exact numbers, 591 per cent, of the nitrogen con- tained in the fresh manure, was wasted. §$ Farmyard Manure. 6. If we replace, in the analysis made on the 15th November, 1855, the number which expresses the amount of insoluble mineral matters by the number 66'93, expressing the proportion of insoluble mineral matters which the manure contained at the commencement of the experiment, and which it would have also contained had no earthy matters been mixed up with the manure, and add to it the other constituents, we obtain for the corrected composition of the whole manure in November, 1855, the fol- lowing numbers, which for comparison's sake are contrasted with the analysis of the fresh manure of November, 1854 : — At conclusion of When put up, experiment, Nov. 3, 1854. Nov. 15, 1855. lbs. lbs. Weight of the manure 1652 950 Amount of water in the manure 1093 G22'8 „ dry substances 559 170*85 Consisting of: — Soluble organic matters 40*97 3-95 ♦Soluble mineral matters 25*43 5*52 flnsoluble organic matters 425*67 94*45 Insoluble mineral matters 66*93 66*93 559*00 170*85 * Containing nitrogen 3-28 "32 Equal to ammonia 3*98 '39 + Containing nitrogen 6*21 3*56 Equal to ammonia 7*54 4*25 Total amount of nitrogen in manure 9*49 3*88 Equal to ammonia 11'52 4(34 The whole manure contained : — Ammonia in free state .. .. '55 '0055 Ammonia in form of salts readily decomposed by quicklime 1*45 *28 Total amount of organic matters .. .. .. 466*64 98*40 ,, mineral matters 92*36 72*45 It will hence appear from these results that the experiment was begun with 559 lbs. of dry manure ; after the lapse of twelve months, only 170*85 lbs. were left behind. Kept for this length of time spread in an open yard, the manure thus lost no less than 69*8 per cent, in fertilizing matters ; or, in round numbers, two-thirds of the manure were wasted^ and only one-third was left behirtd. This fact teaches a most important lesson, and speaks for itself so forcibly that any further comment appears to me useless. In conclusion of this third series of experiments, I may, however, give a Table which may be found useful in calcu- lating the loss in the various fertilizing matters in any given quantity of farmyard manure kept in a similar manner, in which the experimental manure No. 111. was kept. Farmyard Manure, 63 rable showing Loss in the different component parts of Experimental Heap, No. III., Fresh Farmyard Manure (No. III.), Spread, at different periods of the Year; also Per- centage of Loss and Loss per Ton of Fresh Manure. — Quantities stated in lbs. and Frac- tions of lbs. (N.B. The sign * prefixed to a number indicates Increase instead of Loss.) Loss in weight of- Entire heap . . , Water .... S<>lul)le organic matter . Soluble mineral matter. Insoluble organic matter Insoluble mineral matter Containing nitrogen Equal to ammonia . . ■Containing nitrogen . Equal to ammonia . Total amount of nitrogen Equal to ammonia . . Ammonia in free state . Ditto in form of salts . Total amount of organic matter Ditto mineral matter . . . From November 3, 1854, To April 30, 1855. Kept 6 Months. 223- *50- 1-79 2-18 286-30 •12 '80 Percent. Per ton. 13-49 296-77 *3-02 *67-64 1-47 •66 15-85 »l-44 32-92 14-78 355-04 *J2-25 -12 •15 *-018 *-021 2 -68 3-36 *--10 *-50 102 129 2-28 2-95 •050 •53 1-12 17-32 3&7-96 *i;-47 To August 23, 1855. Kept 9 Months. 640' 383-7 36-01 18-96 318-86 *117-54 2-68 3-26 2-67 3-25 6-35 6-50 Per cent. Per ton. 38-74 867-77 23-22 520-12 2-18 1-14 19-29 *7-ll 48-83 25-53 432-09 *159-26 •16 •19 AQ •19 354-87 *98-57 -025 •050 21-47 *j-97 3-58 4-25 3 -.58 4-25 7-16 8-51 480-92 *133-73 To November 15. 1855. Kept 12 Months. 702- 470-20 Per cent. Per ton. I 42-49 28-46 37-02 19-91 331-22 156-36 2-24 1-20 20-05 •9-40 2-96 3-59 2-65 3-29 5-61 6-88 •5445 1-17 368-24 136-44 •18 -21 •16 •19 -033 •07 22-29 *8-25 "•61 9-18 499-29 484-80 Experimental Heap (No. IV.), Well-rotten Dung^ Exposed. — Mixed horse, cow, and pig manure. The fourth and last series of experiments was begun on the 5th of December, 1854, with a view of ascertaining whether or not well-rotten manure is deteriorated in value more rapidly than fresh dung, produced by the same description of animals. The weighings were made on the same days on which the weight of the three preceding experimental heaps were ascertained. In the following Table the results of the direct weighings are stated : Table showing the Weights of Experimental Heap (No. IV.), Well-rott€n Dung, Exposed, and Percentage of Loss. Put up on the .5th of December, 1854 .. Weighed on the 30th of April, 1855, or after! a lapse of 4 mouths and 25 days . . . . / Weighed on the 23rd of August, 1855, or) after a lapse of 8 months and 18 days .. / Weighed on the 15th of November, 1855, ov\ after a lapse of 1 1 months and 10 days . . / Weight of Manure hi lbs. Percentage of \ms&. Analysed at the same periods at which the weighings were made, the following results were obtained : — 64 Farmyard Manure. Table showing Composition of Experimental Manure (No. IV.), Well-rotten Dung, Exposed. In natural state. AVhen put up. Feb. 14th, April 30th, Aug. 23rd, Nov. 15th, Dec. 5th, 1855. 1855. 1855. 1855. 1854. Water 75 '42 73-90 68^93 72-25 71-55 ♦Soluble organic matters .. .. 3-71 2-70 2-21 1-50 1-13 Soluble inorganic matters 1-47 2-06 1-68 1-10 1-04 flnsoluble organic matters 12-82 14-39 15-87 12*46 12-35 Insoluble mineral matters 6*58 6^95 11-31 12-69 13-93 100-00 100-00 100-00 100-00 100-00 ♦Containing nitrogen -297 •149 •14 -090 •09 Equal to ammonia •360 •180 •17 •109 •11 t Containing nitrogen •309 -610 •76 •490 •56 Equal to ammonia •375 •740 •92 •600 •69 Total amount of nitrogen •606 •759 •90 •580 •65 Equal to ammonia •735 •920 1-09 -709 •80 Ammonia in free state . . •046 •015 -006 -013 • ^003 Ammonia in form of salts, easily 1 decomposed by quicklime . . j •057 •048 •044 -040 -029 Total amount of organic matters 16-53 17^09 18-08 13-96 13-48 Total amount of mineral sub-l stances ] 8-05 9-01 12-99 13-79 14-97 It will be seen that at the conclusion of the experiment the manure contained about 4 per cent, less moisture than it did at the beginning. In each experimental period the percentage of water was different, and consequently the direct weighings do not represent accurately the percentage of real loss. In the next Table is given the composition of the same manure, calculated dry. Table showing Composition of Experimental Manure (No. IV.), Well-rotten Dung, Exposed, at different periods of the Year. In dry state. When put up. Dec. 5th, 1854. Feb. 14th, 1855. April 30tb, Aug. 23rd, ' Nov. 15 th, 1855. I 1855. ♦Soluble organic matters . . Soluble inorganic matters •flnsoluble organic matters Insoluble mineral matters ♦Containing nitrogen Equal to ammonia t Containing nitrogen Equal to ammonia Total amount of nitrogen Equal to ammonia Ammonia in free state . . Ammonia in form of salts, easily "I decomposed by quicklime . . / Total amount of organic matters Total amount of mineral sub-) stances J 15-09 5-98 52-15 26*78 10-34 7-89 55-13 26-64 7^11 5^41 51-08 36-40 5-41 3-96 44*90 45-73 3-99 3-67 43-39 48-95 100-00 1 21 1^47 1-26 1-53 2-47 3-00 •189 •232 67-24 32-76 100^00 •57 •69 2-35 2-85 2^92 3 •.54 •057 •183 65^47 34-53 100-00 100-00 1 •45 •32 •54 . -39 2-44 1-76 2-96 2-16 2-89 2-08 3-50 2 ••55 •018 -047 •137 -144 58^19 50-31 41«81 49-69 •32 •39 1^98 2-40 2-30 2-79 •012 •104 47-38 52-62 Farmyard Manure. 65 It will appear from these analyses that in well-rotten farmyard manure the soluble constituents are more readily wasted than is the case with fresh dung kept in the same manner. On the other hand, the percentage of insoluble organic matters, practi- cally speaking, sustained no diminution by keeping the manure in a heap exposed to the weather from December 5th, 1854, to April 30th, 1855. In the two succeeding periods, embracing the warmer months of the year, an appreciable loss in the inso- luble organic matters appears to have taken place ; and it is in the two last periods that the soluble constituents have been wasted more abundantly than in the preceding months. Tiie nature of this loss will become more conspicuous if we calculate from the foregoing data the composition of the whole experimental heap No. IV. This has been done in the sub- joined Table : — Table showing Composition of Whole Heap (No. IV.), Well-rotten Dung, Exposed. In Natural State. Expressed in lbs. and fractions of lbs. Weight of manure Amount of water in the manure Amount of dry matter Consisting of — ♦Soluble organic matter Soluble mineral matter flnsoluble organic matters Insoluble mineral matters ♦Containing nitrogen Equal to ammonia t Containing nitrogen Equal to ammonia Total amount of nitrogen in manure Equal to ammonia The manure contains ammonia in free state , , , , ammonia in form of J salts, easily decomposed by quicklime / Total amount of organic matters . . Total amount of mineral matters . . When put up. Dec. 5 th, 1854. 1613- 1216-5 396-5 59-83 23'71 206-77 106*19 396*5 4-79 5-81 4-99 6-08 9-78 11-89 •74 •92 266-60 129-90 April 30th, 1186- 818' 368- 26-16 19-90 187-97 133-97 368- 1-73 2-10 8-99 10-91 Ang. 23rd, 1855. 1023' 739-1 283-9 15-35 11-24 127*47 129*84 283*9 •90 1-09 4-99 6-06 10*72 13-01 •066 -50 214*13 153-87 5-89 7*15 *13 •40 142*82 141-08 Nov. 15th, 1855. 1003- 737*7 285-3 11-38 10-47 123^79 139*66 $5*30 •92 1*11 5*65 6-89 6*57 8-00 •034 •29 135-17 150^13 A careful comparison of these analytical results will show : — 1. That well-rotten dung loses little in substance during the colder months of the year, provided no heavy rain falls. Should there be continued rainy weather, the result, I have no doubt, would be different from that obtained in my experiments. 2. In the warmer months of the year rotten dung decreases in bulk and in weight more rapidly than in the colder seasons of Farmyard Manure. 3. The loss which well-rotten dung sustains affects principally the soluble constituents. 4. Although rotten dung diminishes less in weight than fresh dung kept in the same manner for the same length of time, yet rotten dung is more readily deteriorated in intrinsic value than fresh. This arises from the circumstance that in rotten dung the proportion of soluble matters is much larger than in fresh. Thus it will be seen that from 59*83 lbs. of soluble organic substances originally present in the manure, only 11-38 lbs. were left over at the conclusion of the experiment, and from 23*71 soluble mineral matters only 10*47 lbs. 5. It will be seen also that hardly a trace of the free ammonia present in the manure when first used for this series of experi- ments is left over by November, 1855 ; and that also the am- monia present in the form of salts, which are easily decomposed by quicklime, is almost altogether dissipated. 6. Finally, it may be observed that in rotten dung exposed to the weather (rain), the nitrogen present in the form of soluble compounds (principally ammoniacal salts) is much more rapidly wasted than in fresh dung. The whole tenor of this fourth series of experiments agrees well with the first series. Having given in the previous pages a detailed account of the changes which fresh manure undergoes in becoming rotten, I shall not offer any further remarks, and con- clude this experimental series by the subjoined tabulated state- ments which may be found acceptable : — Table showing Loss in the different component parts of Experimental Heap, No. IV., well- rotten Dung, Exposed, at dififerent periods of the Year, in natural state ; also Percentage of Loss and Loss per Ton of original Rotten Dung. — Expressed in lbs. and fractions of lbs. (N.B. The sign * prefixed to a number expresses Increase, and not Loss.) • From December 5, 1854, To April 30, 1855. Kept 5 Months. To August 23, 1855. Kept 8 Months. To November 15, 1855. Kept 11 Months. Loss in weight of— Entire heap Water. 427- 398-5 Percent. Per ton. 26-47 1 615-32 24-70 1 553-28 590- 477-4 Per cent. 36-57 29-47 Per ton. 819-16 6C0-12 610- 478-8 Per cent. 37^82 29-69 Per ton 847-16 665-05 ''Soluble organic matter , . . Soluble mineral matter . . [-Insoluble organic matter . . Insoluble mineral matter , . 33-67 4-81 18-80 27-78 2-06 •29 1-16 *l-72 46-14 6-49 25-98 *38-52 44-48 12-47 79-30 *23-65 2-81 •77 4-92 *l-46 62-94 17-24 110-20 *32-70 48-45 13-24 82-98 *33-47 3^00 •82 5^14 *2-07 67-20 18-36 115-13 •46-36 Equal to ammonia .... [-Containing nitrogen . . . Equal to ammonia .... 3.06 3-71 *4-00 4-83 •18 •23 *-24 -29 4^03 5-15 *5-37 6-49 3-89 4-72 0- -02 -24 -29 0- •001 5-37 6-49 0- -02 3-«7 4-70 *-66 *-81 •24 •29 ♦•04 *-05 5 37 6 49 * 89 1-12 Total amount of nitrogen . . Equal to ammonia .... -94 *1-12 *-05 1 *1-12 *-07 1 *1.56 3-89 4-72 •24 -29 5-37 6-49 3-21 3-89 •19 •24 4-48 5-37 Ammonia in free state ... Ammonia in form of salts . . •674 •42 •04 -89 -02 -44 •61 •.=.2 -03 -03 -67 -67 •706 •63 •04 •04 •89 -89 Total amount of organic matters Total amount of mineral matters 52-47 ♦22-97 3-22 1-43 72-12 *32-03 123-78 1 7-73 *11-18 1 *-69 i 173-14 *l5-45 131-43 *20-23 8^14 *l-25 182-33 •28-00 Farmyard Manure. 67 In conclusion, I may mention that I have tested the various experimental manures at different times for nitrates, and have been able to detect the presence of nitric acid in most cases in which the manure had been kept lor some time in contact with the atmosphere. Under all circumstances, however, the propor- tion of nitric acid appeared to amount to mere traces ; and, as I am not acquainted with any accurate method of determining minute quantities of nitric acid in so complex a mixture of sub- stances as that of farmyard manure, I have not attempted to deter- mine the amount of nitric acid in the manure quantitively. I may be permitted, however, briefly to state the results of my qualitative examinations : — Qualitative examination for Nitrates, Fresh, farmyard manure (about 14 days) -wy old) examined Nov. 3rd, 1854 .. } ^« ^"^^^^^^^^ Well-rotten dung taken from the bottom \ of manure-pit on the 5th of Dec, 1854 j » ' Analyses made February 14th, 1855. ''^rS^tT .''"•.'■■ ':"' 'r""r'} ^^-^-^ »-- of nitnc ac-d. '"^rZ^ret^er^U;"-:/"!' '^T'] Doubtful trace of nitric add. Experimental heap, No. III., well-rottenf Nitric acid distinctly present, ap- ^ung exposed''.. .. '. j En^Na I. ''"'™'*'"""" Analyses made April 30th, 1855. Experimental heap, No. I., fresh manure! t\- 4.' ^ 4. e ',. • -j exposed I ^^^^^^^^ tra<^s of nitric acid. Experimental heap. No. II., fresh manure) under shed j '' »» Experimental heap. No. III., fresh manure ) -kj , . spread out J iNo reaction. Experimental heap, No. IV., well-rotten ) t-*- 4.- ^ x c -,. - -j dung exposed , .. .. .. .. } ^istmct traces of nitrac acid. Analyses made August 23rd, 1855. ^rjSSd"*^ ^^:. ^"■.^■' .'^''''. ""™''} Distinct tmcesof nitric acid. ^ ™de?sM ^f*P' .^"•.^^•' fr'^1'^^"^^"'*} The same as in May. Experimental heap, No. III., fresh manure) a f • + f spread out | a lamt trace. Experimental heap. No. IV., well-rotten I Stronger reaction of nitric acid, dung exposed J than in May. It will be seen that there was no nitric acid present in the fresh manure, nor in the rotten dung taken from the bottom of the pit ; and, as traces of nitrates were detected in the manure after a three-months' exposure to the weather, it would seem to follow that access of air is essential for the formation of nitrates 68 Farmyard Manure. in the manure. I was rather surprised not to find any decided traces of nitric acid in the manure spread out in the yard. But as nitrates are very soluble in water, and the spread manure con- tained a very small proportion of soluble saline matters, it is evident that, if nitrates have been formed, they must have been washed into the soil on which the manure was spread. Coriclusion. — Having described at length my experiments with farmyard manure, it may not be amiss to state briefly the more prominent and practically interesting points which have been developed in the course of this investigation. I would therefore observe, — 1. Perfectly fresh farmyard manure contains but a small pro- portion of free ammonia. 2. The nitrogen in fresh dung exists principally in the state of insoluble nitrogenized matters. 3. The soluble organic and mineral constituents of dung are much more valuable fertilizers than the insoluble. Particular care, therefore, should be bestowed upon the preservation of the liquid excrements of animals, and for the same reason the manure should be kept in perfectly waterproof pits, of sufficient capacity to render the setting up of dungheaps in the comer of fields, as much as it is possible, unnecessary. 4. Farmyard manure, even in quite a fresh state, contains phosphate of lime, which is much more soluble than has hitherto been suspected. 5. The urine of the horse, cow, and pig, does not contain any appreciable quantity of phosphate of lime, whilst the drainings of dungheaps contain considerable quantities of this valuable fer- tilizer. The drainings of dungheaps, partly for this reason, are more valuable than the urine of our domestic animals, and there- fore ought to be prevented by all available means from running to waste. 6. The most effectual means of preventing loss in fertilizing matters is to cart the manure directly on the field whenever cir- cumstances allow this to be done. 7. On all soils with a moderate proportion of clay no fear need to be entertained of valuable fertilizing substances becoming wasted if the manure cannot be ploughed in at once. Fresh, and even well-rotten, dung contains very little free ammonia ; and since active fermentation, and with it the further evolution of free ammonia, is stopped by spreading out the manure on the field, valuable volatile manuring matters cannot escape into the air by adopting this plan. As all soils with a moderate proportion of clay possess in a remarkable degree the power of absorbing and retaining manuring Farmyard Manure. 89 matters, none of the saline and soluble organic constituents are wasted even by a heavy fall of rain. It may, indeed, be ques- tioned whether it is more advisable to plough-in the manure at once, or to let it lie for some time on the surface, and to give the rain full opportunity to wash it into the soil. It appears to me a matter of the greatest importance to regu- late the application of manure to our fields so that its consti- tuents may become properly diluted and uniformly distributed amongst a large mass of soil. By ploughing in the manure at once, it appears to me, this desirable end cannot be reached so perfectly as by allowing the rain to wash in gradually the manure evenly spread on the surface of the field. By adopting such a course, in case practical experience should confirm my theoretical reasoning, the objection could no longer be maintained that the land is not ready for carting manure upon it. I am much inclined to recommend as a general rule : Cart the manure on the field, spread it at once, and wait for a favourable opportunity to plough it in. In the case of clay soils, I have no hesitation to say the manure may be spread even six months before it is ploughed in, without losing any appreciable quantity of manuring matters. I am perfectly aware that, on stiff clay- land, farmyard manure, more especially long dung, when ploughed in before the frost sets in, exercises a most beneficial action by keeping the soil loose and admitting the free access of frost, which pulverizes the land, — and would therefore by no means recommend to leave the manure spread on the surface without ploughing it in. All I wish to enforce is, that when no other choice is left but either to set up the manure in a heap in a corner of the field, or to spread it on the field, without ploughing it in directly, to adopt the latter plan. In the case of very light sandy soils it may perhaps not be advisable to spread out the manure a long time before it is ploughed in, since such soils do not possess the power of retaining manuring matters in any marked degree. On light sandy soils I would suggest to manure with well-fermented dung shortly before the crop in- tended to be grown is sown. 8. Well-rotten dung contains likewise little free ammonia, but a very much larger proportion of soluble organic and saline mineral matters than fresh manure. 9. Rotten dung is richer in nitrogen than fresh. 10. Weight for weight, rotten dung is more valuable than fresh. 11. In the fermentation of dung a very considerable propor- tion of the organic matters in fresh manure, is dissipated into the air in the form of carbonic acid and other gases. 12. Properly regulated, however, the fermentation of dung is 70 Farmyard Manure. hot attended with any great loss of nitrogen nor of saline mineral matters. 13. During the fermentation of dung, ulmic, humic, and other organic acids are formed, as well as gypsum, which fix the am- monia generated in the decomposition of the nitrogenized con- stituents of dung. 14. During the fermentation of dung the phosphate of lime which it contains is rendered more soluble than in fresh manure. 15. In the interior and heated portions of manure-heaps am- monia is given off ; but, on passing into the external and cold layers of dungheaps, the free ammonia is retained in the heap. 16. Ammonia is not given off from the surface of well-com- pressed dungheaps, but on turning manure-heaps it is wasted in appreciable quantities. Dungheaps for this reason should not be turned more frequently than absolutely necessary. 17. No advantage appears to result from carrying on the fer- mentation of dung too far, but every disadvantage. 18. Farmyard manure becomes deteriorated in value, when kept in heaps exposed to the weather ; the more the longer it is kept. 19. The loss in manuring matters, which is incurred in keeping manure-heaps exposed to the weather, is not so much due to the volatilization of ammonia as to the removal of ammoniacal salts, soluble nitrogenized organic matters, and valuable mineral mat- ters, by the rain which falls in the period during which the manure is kept. 20. If rain is excluded from dung-heaps, or little rain falls at a time, the loss in ammonia is trifling, and no saline matters of course are removed ; but, if much rain falls, especially if it descends in heavy showers upon the dungheap, a serious loss in ammonia, soluble organic matters, phosphate of lime, and salts of potash is incurred, and the manure becomes rapidly deterio- rated in value, whilst at the same time it is diminished in weight. 21. Well-rotten dung is more readily affected by the dete- riorating influence of rain than fresh manure. 22. Practically speaking, all the essentially valuable manuring constituents are preserved by keeping farmyard manure under cover. 23. If the animals have been supplied with plenty of litter, fresh dung contains an insufficient quantity of water to induce an active fermentation. In this case fresh dung cannot be properly fermented under cover, except water or liquid manure is pumped over the heap from time to time. Where much straw is used in the manufacture of dung, and no provision is made to supply the manure in the pit at any time with the requisite amount of moisture, it may not be ad- Farmyard Manure. Tl visable to put up a roof over the dung-pit. On the other hand, on farms where there is deficiency of straw, so that the moisture of the excrements of our domestic animals is barely absorbed by the litter, the advantage of erecting a roof over the dung-pit will be found very great. 24. The worst method of making manure is to produce it by animals kept in open yards, since a large proportion of valu- able fertilizing matters is wasted in a short time ; and after a lapse of twelve months at least two-thirds of the substance of the manure is wasted, and only one-third, inferior in quality to an equal weight of fresh dung, is left behind. 25. The most rational plan of keeping manure in heaps ap- pears to me that adopted by Mr. Lawrence of Cirencester, and described by him at length in Morton's ' Cyclopaedia of Agri- culture,' under the head of ' Manure.' APPENDIX. The methods employed for determining the water, and selecting samples for analysis, have been stated already in the preceding pages. I can, therefore, proceed at once with the description of the other methods which were adopted in the analysis of the manure. One thousand, and sometimes two thousand, grains of a carefully mixed sample of manure were digested in a glass beaker with about 16 ounces of cold distilled water for about three or four hours. The liquid was then strained through calico, and the residue digested a second time with about 10 ounces of water; the liquid was again passed through calico, and the residue thoroughly squeezed out. It was next digested again in water, pressed out, and repeatedly washed on the calico until the water came perfectly clear through the calico, and left on evaporation merely a trace of solid matter. In this way a quantity of liquid was obtained (by employing 1000 grains of manure), which filled about a Winchester quart. As it was impossible to obtain a perfectly clear liquid by repeated filtrations through fine filtering paper, the watery solution of the dung was kept in carefully-stoppered Win- chester quarts for three or four days, or until the liquid became perfectly clear on standing. It was then drawn off with a syphon into another bottle, and the deposit in the first bottle carefully collected in a weighed filter, and this weight added afterwards to that of the portion of dung insoluble in water. The insoluble portion was previously dried in the air-bath at 212° Fah. The weight of the whole solution having been ascertained, separate portions of it were employed for the determination of the total amount of soluble matters. Generally three, sometimes four, weighed portions of the Hquid were evaporated separately to dryness, first in glass beakers, and finally in a large platinum basin over the water-bath. The platina basin and residue was then dried in the air-bath, until it ceased to lose in weight. The dry residue of two evaporations was burned over the gas-lamp to a whitish ash, and thus the amount of soluble organic and inorganic matters determined. The dry residue of the third and fourth evajwration was reserved for the determination of the nitrogen in the soluble matters of the manure. 72 Farmyard Manure. In a similar manner the proportions of organic and inorganic matters in the insoluble portion of the manure was ascertained. The nitrogen was determined in each portion separately by combustion with soda-lime, and collecting the ammonia produced in sulphuric acid of known strength, according to Peligot's method of determining nitrogen in organic matters. Frequently two combustions were made with one and the same substance, and invariably closely-agreeing results obtained. The ash-analyses of the soluble and the insoluble mineral matters of manure, were executed according to the method described in Professor Wohler's * Handbook of Inorganic Analysis,' under the head *' Analyses of the Ashes of Plants." The amount of free ammonia in the manure was ascertained by placing into a wide-mouthed retort from 500 to 1000 grains of manure, adding about 8 ounces of water, and distilling oif about 4 ounces into a glass bottle, con- nected air-tight with the retort on the one hand, and on the other with the bulb apparatus usually employed in nitrogen combustions. Both the bottle and the bulb apparatus contained some hydro-chloric acid. The contents of both were evaporated to dryness on the water-bath, and from the dried residue the amount of free ammonia calculated. To the manure in the retort, from which the free ammonia was distilled off, quicklime and a little more water was added, and the whole distilled nearly to dryness into hydro-chloric acid as before. Distilled water was next poured upon the mixture of quicklime and manure in the retort, and after some time the liquid filtered through filtering pai)er. The insoluble portion was washed several times, and the washings added to the first filtrate, and the whole clear solution evaporated to a very small bulk. This condensed liquid, which in most cases was coloured merely light yellow, finally was tested for nitric acid with the usual tests. LONDON : PRINTED BV W. CLOWES AND SONS, STAMFOKD STREET, AND CHARINO CROSS. ON FARMYARD MANURE, THE DRAININGS OF DUNG-HEAPS, AND THE ABSORBING PROPERTIES OF SOILS. BY DR. AUGUSTUS YOELCKER. LONDON; PRINTED BY W. CLOWES AND SONS, STAMFORD STREET, AND CHARING CROSS. 1857. FROM THE JOURNAL OF THE ROYAL AGRICULTURAL SOCIETY OF ENGLAND, VOL. XVIU., PART I. ON FARMYARD MANURE, It is a prevailing opinion amongst farmers that the peculiar smell which emanates from dung-heaps is caused by the escape of ammonia, and that the deterioration of farmyard manure is due, in a great measure, to the loss of this most fertilizing substanccf which is incurred by careless management of dung- heaps. In a paper published in the volume for 1856 of the Journal of the Royal Agricultural Society, however, I showed that the proportion of free ammonia, or rather vola- tile carbonate of ammonia — for it is in this form that ammonia makes its appearance in putrefying organic matters — is so inconsiderable in fresh as well as in fermented dung in all stages of decomposition, that it is not worthy to be noticed in a practical point of view. This being the case, it is evi- dent that the escape of ammonia cannot be the cause of ma- nure-heaps losing much in fertilizing property even when freely exposed to the atmosphere for a considerable length of time. Consequently the chemical means which have been suggested from time to time for preventing the loss of ammonia in dung-heaps may be altogether dispensed with. As there is, practically speaking, no free ammonia in either fresh or rotten dung to be fixed, the addition of dilute sulphuric acid, a solution of green vitriol, and other chemical agents which change volatile compounds of ammonia into non-volatile combinations, is unnecessary and useless. At any rate, these and other fixers of ammonia are useful additions to dung-heaps only in so far as they themselves possess fertilizing properties. In the paper to which reference has been made, I furnished experimentally the proof that, simultaneously with the formation of ammonia — which always proceeds when organic substances containing nitrogen b2 4 Farmyard Manure, enter into putrefaction — under ordinary circumstances, ulmic, humic, and similar organic acids are produced, which, on account of their great affinity for ammonia, lay hold of any free ammonia generated from excrementitious matters and effectually fix it, provided the temperature of the heap is kept down sufficiently low. In the interior of a dung-heap, where the heat rises often to a temperature of from 120° to 150° F., ammonia, indeed, is given off so abundantly that its presence here becomes patent by its characteristic pungent smell. Such a smell is always observed on turning a manure-heap in an active state of fer- mentation. Fortunately, the external cold layers of dung-heaps act as a chemical filter, and retain the ammonia proceeding from the heated interior portions of the heap so effectually that even a delicate red litmus paper is not altered in the least. As the faintest traces of ammonia turn reddened litmus paper dis- tinctly blue, it is plain that, however strong the smell of a dung- heap may be, it cannot be due to the escape of ammonia if the red colour of the paper is not turned blue by holding it, pre- viously moistened with water, close to a dung- heap. Some doubts having been expressed of the accuracy of this observation, I have repeatedly examined manure-heaps for free .ammonia. Numerous experiments, which need not be described in detail, have fully confirmed my former observations. It is true a manure-heap which has just been turned, or which is examined the day after, gives off a small quantity of ammonia. Although this amounts to a mere trace, yet it distinctly affects red litmus pape»; but when a dung-heap is allowed to consolidate for a week or so, and is then examined with litmus paper, not a trace of free ammonia can be detected in the air close to the dung- heap, whilst no difficulty is experienced in detecting free am- monia in the interior heated portions of the same heap. I have since found that farmyard manure, perfectly free from volatile carbonate or uncombined ammonia, when macerated in boiling water, gives off a slightly pungent smell, which, as far as its pungency is concerned, is caused by the escape of ammonia. It appeared to me a matter of some interest to investigate the circumstance that ammonia is given off only in the interior of the heap and not from its surface, and also how it is that manure which does not contain a trace of free ammonia at the heat of boiling water gives off this gas in appreciable quantity. In the course of this investigation, 1 was led to the chemical examina- tion of the drainings of dung-heaps, and obtained results which, I believe, are of sufficient interest to be recorded in a Journal devoted to the promotion of good agricultural practice and sound scientific principles. Farmyard Manure, 5 Before describing the nature of my experiments with drainings of dung-heaps, and stating the analytical results obtained in the analyses of this liquid, I may be allowed to offer a few additional experimental proofs in support of some of the opinions advanced in my paper on the changes which farmyard manure undergoes on keeping. In order to obviate frequent reference to this paper, I would observe that, amongst other particulars, I showed that perfectly fresh as well as rotten dung contained but a very trifling amount of free ammonia ; that short dung, when properly fer- mented, contains more nitrogen than long dung ; for which reason, weight for weight, rotten dung is more valuable than fresh. Respecting the loss which farmyard manure sustains under various circumstances, 1 furnished numerous experiments, which prove that farmyard manure is deteriorated in value when kept in heaps exposed to the weather — the more the longer it is kept ; and that the loss in manuring matters which is incurred in this way is not so much due to the volatilization of ammonia as to the removal of ammoniacal salts, soluble nitrogenized organic matters, and soluble mineral matters, by the rain which falls in the period during which the manure is kept. I further showed that well-rotten dung is more readily affected by the deteriorating influence of rain than fresh, and that no advantage appears to result from carrying on the fermentation of dung too far. Finally, I described several experiments, which led me to the conclusion that the worst method of making manure is to produce it by animals kept in open yards, inasmuch as a large proportion of valuable fertilizing matters is thereby wasted in a short time, and suggested, as the most effectual means of preventing loss in fertilizing matters, to cart the manure directly on the field, and to spread it at once, whenever circumstances allow this to be done. Since the publication of my former experiments on farmyard manure, T have had an opportunity of examining some sheep- dung in a highly advanced state of decomposition. This exa- mination has brought out strikingly that the richest excrementi- tious. matters are greatly deteriorated in value by keeping for an immoderate lengthy period, and I may therefore be permitted to state here the results in full. The sheep- dung operated upon was furnished to me by a farmer residing in the neighbourhood of Cirencester, who kept this dung for three years in a heap, probably with a view of manufacturing it into a first-rate turnip manure. It was com- pletely decomposed, appeared as a black greasy mass, and pos- sessed more of an earthy than an animal smell. c 6 Farmyard Manure. A well-mixed sample, on analysis, yielded the following general results: — General Composition of Decomposed Sheep Dung (3 years old). In Natural State. Calculated Dry. Water 73-66 ♦Soluble organic matter 2*70 10*25 Soluble inorganic matter 2*66 10'09 flnsoluble organic matter 9'95 37*78 Insoluble mineral matter 11*03 41*88 100*00 100*00 ♦ Containing nitrogen *157 *590 Equal to ammonia '190 'TIS t Containing flitrogen '470 1*790 Equal to ammonia *580 2*170 Total amount of nitrogen *627 2*380 Equal to ammonia *770 2*886 A delicate reddened litmus paper inserted into the neck of a wide-mouthed bottle, into which some of this sheep-dung was placed, was not altered in the slightest degree ; there was thus not a trace of free ammonia present in the dung. When boiled with water, a small portion of ammonia was given off, but that quantity was so insignificant that I determined at once the total amount of ammonia which existed in the dung in the form of ammoniacal salts. This was done by distillation with quick lime and collecting the liberated ammonia in hydro- chloric acid, evaporation to dryness in a water-bath, and weighing the residue consisting of sal ammoniac. Proceeding in this way, I obtained from 100 parts of com- pletely decomposed sheep-dung — In Natural State. Calculated Dry. Ammonia -034 *129 (In the state of ammoniacal salts.) It appears, therefore, that the amount of ammonia present in the form of ammoniacal salts is exceedingly small. In separating the soluble from the insoluble portion some very finely divided silica passed through the filter, and was obtained in the soluble portion of the ash. This portion of the ash contained in 100 parts : — Farmyard Manure. 7 Completely Rotten Sheep-Manure. Composition of Ash of portion Soluble in Water. Soluble silica 30*70 Insoluble silica 15'90 Phosphate of lime 21*70 Lime 3*93 Magnesia 6*37 Potash 14*14 Soda 3*15 Chloride of sodium, .. -85 Sulphuric acid 2*86 Carbonic acid and loss '40 100*00 The composition of the insoluble portion of the ash is stated in the next diagram : — Completely Rotten Sheep-Manure. Composition of Ash of portion Insoluble in Water. Soluble silica 11-25 Insoluble silica 62*81 Oxides of iron and alumina, with phosphates 9*12 containing phosphoric acid (4*93) equal to bone earth (10*68) Lime 7*95 Magnesia 2*88 Potash *59 Soda -50 Sulphuric acid 1*18 Carbonic acid and loss 3*72 100*00 From these results the composition of the whole ash of sheep's dung, kept for three years, has been calculated and embodied in the subjoined table. Completely Rotten Sheep-Manure, Composition of whole Ash. Soluble silica 5*95 Insoluble silica 3'jC)i8 Phosphate of lime . . . . 4*21 Lime '76 Magnesia 1*28 Potash .. ■ 2*74 Soda -61 Chloride of sodium '16 Sulphuric acid '55 Carbonic acid and loss *07 S3 05 (19*41) c 2 ^ 'o 6 Farmyard Manure, Soluble silica 9-06 Insoluble silica 50*61 Oxides of iron and alumina with phosphates 7 "34 containing phosphoric acid (4-07) equal to bone earth (8'52) Phosphate of lime Lime 6-40 Magnesia 2*31} Potash -47 Soda -40 Chloride of sodium Sulphuric acid -95 Carbonic acid and loss 3 04 Arranged together. 15-01 53-69 7-34 (4-07) (8-52) 4-21 7-16 3-60 3-21 1-01 •16 1-50 3-11 (80-59) 100-00 100-00 A comparison of the asli of sheep's dung, kept for three years, with the ash of well-rotten good common farmyard manure, will show that in the latter the proportion of phosphate of lime is somewhat larger, and that it is especially much richer in potash than this sheep's dung. On the other hand, this sample of sheep's dung contains a great deal more of silica and earthy matters insoluble in water. It is thus evident that by long keeping the most valuable inorganic constituents of sheep's dung are washed out gradually, and by their loss the dung becomes greatly deteriorated in fertilising properties. The next Table exhibits the detailed composition of this com- pletely rotten sheep's dung. Completely Rotten Sheep-Manure. Detailed Composition of Manure in Natural State. Water 73-66 * Soluble organic matter 2-70 Soluble inorganic matter (ash) : — Soluble silica -801 Insoluble silica -422 Phosphate of lime -577 Lime -104 Magnesia -169 Potash -376 Soda .. -083 Chloride of sodium -022 Sulphuric acid -076 Carbonic acid and loss -030 2-66 Carry forward . . 79-02 Farmyard Manure, 9 Brought forward .. .. 79*02 t Insoluble organic matter 9*95 Insoluble inorganic matter (ash) : — Soluble silica 1*240. Insoluble silica 6*927 Oxides of iron and alumina, with phosphates . . 1*005 containing phosphoric acid (*543J equal to bone earth (1*176) Lime *876 Magnesia *317 Potash -065 Soda -055 Sulphuric acid '130 Carbonic acid and loss 'dlS 11*03 100-00 * Containing nitrogen 'IST Equal to ammonia *190 t Containing nitrogen '47 Equal to ammonia . . . . '58 Whole manure contains ammonia in free state, and in form of salts \ '034 According to these results, the same dung in a perfectly dry condition has the following composition : — Completely Rotten Sheep's Dung. Detailed Composition of Manure in Dry State, *Soluble organic matter 10*25 Soluble inorganic matter (ash) : — Soluble silica 3*097 Insoluble silica 1*604 Phosphate of lime 2*189 Lime '405 Magnesia • . . '642 Potash 1*426 Soda -317 Chloride of sodium 'OSS Sulphuric acid *288 Carbonic acid and loss '040 10*09 tinsoluble organic matter 37*78 Insoluble inorganic matter (ash) ; — Soluble silica 4*711 Insoluble sihca 26*304 Oxide of iron and alumina, with phosphates 3*819 containing phosphoric acid (2*06) equal to bone earth (4*46) Lime 3*329 Magnesia 1*196 Carryforward .. .. 58*12 10 Farmyard Manure. Brought forward .. .. 58*12 Potash -247 Soda -209 Sulphuric acid -494 Carbonic acid and loss 1*557 41*88 100-00 * Containing nitrogen '59 Equal to ammonia •716 t Containing nitrogen 1 • 79 Equal to ammonia 2*17 Whole manure contains ammonia in free state, ) . ^q and in form of salts j *^^ From these analytical results it appears — 1. That completely rotten dung contains less soluble organic matters than well rotten common farmyard manure. 2. That the proportion of insoluble organic matters in such sheep's dung is also much smaller than in rotten yard manure. 3. That the amount of nitrogen in rotten farmyard manure is greater than in this sheep's dung. 4. That, weight for weight, ordinary well rotten dung is more valuable than such completely decomposed sheep's dung. When it is considered that the diminution of manure in weight by long keeping is very considerable, and that the remaining manure, reduced it may be to one-third its original weight, is less valuable than even common farmyard manure, the folly of keeping sheep's dung in a heap for a number of years will become apparent. As it may not be uninteresting to compare this manure with fresh sheep's dung, I will insert here a Table representing the general composition of fresh sheep's dung, as recently determined by me : — General Composition of Fresh Sheep's Dung (Sheep fed upon Hoots on old Pasture.) In Natural State. Calculated Dry. Moisture .. 73*13 * Organic matters 20*28 75*47 Inorganic matters (ash) .. 6*59 24*53 100*00 100*00 * Containing nitrogen '95 3*53 Equal to ammonia 1*15 4*29 Fresh sheep's dung thus contains considerably more nitrogen than the sample of completely rotten dung which was analysed by me. During the first stages of the fermentation of dung the pro- portion of nitrogen in manure increases, but when well-fermented Farmyard Manure. 11 dung is then exposed to the weather, the nitrogenized consti- tuents which have been rendered soluble during the process of fermentation are liable to be washed out by rain. The analyses of fresh and completely rotten sheep's dung confirm my former observations — that in this way a great loss is incurred in valuable fertilising matters. As a further proof of the fact that both fresh and rotten farm- yard manure contains but a trifling amount of free ammonia, I have to mention two experiments. The first was made with fresh horse-dung, or, more properly speaking, with the recent droppings of horses mixed with straw ; that is, horse-dung as found in stables before its removal to the dung-pit. This manure contained in 100 parts ; Water 76-60 Solid matter 23'40 100-00 The percentage of ammonia, which was driven out by long-continued boiling, amounted to . . 0'0033 Quicklime added to remainder expelled in addition to this quantity 0-062 p. ct. of am. The total amount of nitrogen in this manure amounted to 0'3S7 p. ct. Which is equal to 0-469 p. ct. of am. Or dried at 212° F. the manure contained — Nitrogen 1-655 p. ct. Equal to ammonia 2-019 p. ct.' The second experiment was made with hot fermenting horse- dung, taken from the middle of a heap of good farmyard-manure, consisting chiefly of horse-dung. It emitted a strong and some- what pungent smell, for reddened litmus paper inserted into the neck of a bottle into which some of this manure was placed turned blue after some time, showing that it contained some free ammonia. The quantity of the latter, however, was very incon- siderable, as will be seen by the following numbers, obtained like those in the experiment with fresh horse-dung : — Percentage of free ammonia in fermenting horse-dung 0-049 Distilled with quicklime, it furnished additional .. 0*1103 p. ct. of am. This manure calculated in 100 parts : Calculated Dry. Moisture 68-74 * Solid matters 31-26 100 100-00 C ontaining nitrogen 0-659 2-109 Equal to ammonia -800 2 '561 12 Farmyard Manure. In fermenting horse-rdung, the proportion of nitrogen is thus larger than in fresh, which agrees well with previous analyses of fresh or rotten common yard-manure ; whilst in perfectly fresh horse- dung the amount of free ammonia is scarcely weighable, it being only about 3 parts in every 100,000 parts of dung, or 3 lbs, for every 40 tons ; the same description of manure in an active state of fermentation yields somewhat more, but still a very incon- siderable quantity of free ammonia. Thus under the most favourable circumstances 100,000 parts of horse-dung yield only 49 parts of free ammonia ; or in other words 40 tons in round numbers yield on long-t ontinued boiling only 49 lbs. of ammonia. It must not be supposed, however, that this quantity of ammonia is dissipated into the air during the fermentation of the dung, for it is only in the interior of the dung-heap that ammonia is libe- rated. It is, indeed, only on turning a heap that ammonia escapes at all in any perceptible degree ; but as soon as the ex- ternal layers have become cooled down to the ordinary temperature of the air its escape is arrested. There can, therefore, be not the slightest doubt that a very minute quantity of ammonia passes into the air and the remainder is fixed in the heap, provided the heap is kept in such a manner that rain cannot remove from it much of the soluble matters, and with them ammoniacal salts. The strong smell which is observed on turning a dung-heap no doubt has led many greatly to over-estimate the amount of ammonia which escapes from farmyard manure in an active state of fermentation. But I would observe that nothing is more fal- lacious than the estimation of the amount of ammonia by the pungency of the smell which is given off from fermenting animal matters. Such matters often give off a very powerful smell, which is due to peculiar volatile organic combinations — to some sulphuretted and phosphoretted hydrogen and a great variety of gaseous matters, amongst which there is ammonia gas in very minute quantities. The smell of this highly complicated and but scantily examined mixture of gaseous matters as a whole is ascribed by the popular mind to ammonia. From these products of putrefaction, however, ammonia can be completely separated, without in the least destroying the peculiar offensive smell which emanates from organic matters in a state of decomposition. If, for instance, dilute sulphuric acid is added to farmyard manure or liquid manure, the smell of tliese substances, instead of becoming neutralised by the acid, in reality becomes more offen- sive. This arises in a great measure from the liberation of sul- phuretted hydrogen. Hence acids are not well adapted for dis- infecting cesspools or nightsoil. As dilute sulphuric acid neutralises instantly free ammonia, forming with it an inodorous Farmyard Manure. 13 salt, which is not volatile at the ordinary temperature, it is evi- dent that the foetid smell of putrefying matters has much less to do with ammonia than is generally believed. The following experiment is decisive in this respect. A couple of ounces of genuine Peruvian guano were completely drenched with dilute sulphuric acid. Any free ammonia in the guano by the addition of acid must therefore have been instantly converted into sulphate of ammonia. The characteristic smell of the guano, however, was not removed nor even weakened by the acid. The guano moistened with acid was next dried in a water-bath for five or six hours, and during all that time gave off the strong peculiar smell which characterises genuine Peruvian guano. Wlien dry it still smelt strongly, though weaker than when wet ; but moistened again with a little water the smell again became as strong as before. In order to make quite certain that no ammonia would remain in a free state, I employed a great excess of acid, in consequence of which the guano, after drying up with acid, tasted as acid as any of the most concentrated samples of superphosphate. I may further mention that I dried guano for days at a tempe- rature of boiling water without being able to remove its peculiar smell. Whilst speaking of guano it may interest some of my readers to learn that genuine Peruvian guano contains a very small quantity of volatile carbonate of ammonia. There are many people who run wild with the idea that every- thing that smells strongly must contain free ammonia. Hence it is not surprising that salt, gypsum, acids, and various other sub- stances should have been suggested to be mixed with guano for the purpose of fixing the ammonia, as it is said, in guano. It is not my purpose to enter here into a discussion of the merits of salt or gypsum as fixers of ammonia, but I cannot help observing that both salt and gypsum are ill adapted for fixing any free ammonia in putrefying organic matters. I do not mean to speak disparagingly of the mixing of salt or gypsum with guano, for I believe this to be attended with very great benefit. The good effected by mixing guano with salt, how- ever, I feel assured is not due to the salt fixing the ammonia in guano, as generally believed by practical men, and transcribed from one text-book on agricultural chemistry to the other ; for in the first place salt is incapable of fixing any free ammonia in guano, and in the second place the amount of free ammonia in genuine Peruvian guano is so inconsiderable, that salt, even supposing it to fix ammonia, finds very little free ammonia in Peruvian guano upon which to exercise its supposed power of fixing ammonia. 14 Farmyard Manure. A year or two ago Mr. Barrall, a French chemist, published some experiments, which purpose to prove the power of salt to fix ammonia in Peruvian guano, and to account thereby for the benefit which results from the mixing of guano with salt. I have carefully repeated Mr. Barrall's experiments, and shall publish the details of my analytical results shortly elsewhere ; but, fearing I might be considered dogmatic in distinctly stating that salt is incapable of fixing free ammonia in guano, I beg to observe that 1 have been led to this conclusion by a series of experiments which are opposed in their results to Mr. Barrall's. For the purpose of giving an idea of the actual quantity of free ammonia (carb. of ammonia) in Peruvian guano, I would mention in this place the following experiment : — A quantity of Peruvian guano, which on analysis gave the subjoined analytical results, was mixed with a little water, and distilled in a retort to dryness at a temperature not exceeding 212° F., and the distillate care- fully collected in hydrochloric acid. On evaporation of the acid liquor in the receiver, sal ammoniac was obtained, from the weight of which that of ammonia volatilised with the watery vapours produced on distillation was calculated. The following is the result of this determination. 100 parts of genuine Peruvian guano were found to yield "573 of am- monia : — Composition of Peruvian Ouano used in this Experiments Moisture 12-78 * Organic matter and amraoniacal salts . . . . 53*08 Phosphates of lime and magnesia (bone-eartb) 24-50 Alkahne salts 8-99 Insoluble silicious matter (sand) -65 100-00 * Containing nitrogen 13*18 Equal to ammonia 15*96 The same guano distilled with an excess of quicklime and some water, with a view of liberating the ammonia which existed in this sample of Peruvian guano in the form of ammoniacal salts, produced 6-931 of ammonia. Though we are in the habit of speaking of guano as an ammoniacal manure, it appears from these determinations that the smaller proportion of nitrogen is contained in Peruvian guano as ready-formed ammonia, and the larger proportion as uric acid, urea, and other nitrogenised com- pounds, which, however, in contact with water, are readily decomposed and yield ammonia. The quantity of free ammonia and ammonia in the form of ammoniacal salts, of course, is not constant in different samples : I may state, however, that in dry genuine Peruvian guano I Farmyard Manure, 15 never found a larger amount of free ammonia than f per cent. This small proportion of free ammonia cannot excite surprise if the conditions are taken into account under which guano is depo- sited in the rainless regions from which good Peruvian guano is imported into this country. The dry and hot climate of the Peruvian guano islands has the effect of leaving very little free ammonia in the fresh birds' excrements, and of rapidly dissi- pating the moisture which they contain. With the expulsion of the moisture the further decomposition of the excrements is at once arrested, and the further development of ammonia prevented. It follows from these remarks that as long as Peruvian guano is kept perfectly dry it may be preserved for any length of time without losing in the slightest degree in fertilising properties, and also that there exists no need of resorting to chemical sub- stances which are known to possess the property of fixing ammonia. The case is different with damaged and inferior descriptions of guano. These frequently contain considerable quantities of volatile carbonate of ammonia ; they are therefore liable to become deteriorated on long keeping, and may be improved by the addition of an acid which fixes the free ammonia. Indeed, all guanos which are deposited in districts occasionally visited by heavy rains contain much carbonate of ammonia, a salt which in inferior guanos is often seen in beautiful large crystals, and which, being volatile, is gradually dissipated by keeping. It has been stated already that there exists no necessity for fixing ammonia in farmyard manure by chemical means. But I refer again to this subject on account of a statement M^hich has been widely circulated and been reported in most agricultural periodicals. It has been stated, namely, by a Mr. M'Dougall, the patentee of a disinfecting powder, that by the use of the patent article, not only the air in stables may be kept perfectly sweet and wholesome, but that also the quality of the dung is improved in an astonishing degree, so much so, that in the neighbourhood of Manchester fabulous prices have been paid for. farmyard manure, in the preparation of which M^Dougall's powder has been used. I am bound to state at once, that this powder possesses, indeed, excellent disinfecting properties ; and had the inventor confined his remarks to the sanitary question involved in the use of his powder, no room would have been left to call in question its utility as a disinfectant. But as he describes, in addition to its disinfecting properties, others which I have not found confirmed in my experiments on the subject, I am anxious to correct any erroneous views to which some of Mr. M'Dougall's statements may have given rise. It is maintained 16 Farmyard Manure. by this gentleman that his disinfecting powder possesses the property of fixing ammonia in dung, and thereby rendering it more valuable than manure made in the ordinary manner. . According to the published accounts, M'Dougall's powder consists chiefly of sulphite of lime and sulphite of magnesia, and contains also some carbolic acid in combination with lime, and free lime. It is said to be prepared by passing sulphurous acid into slaked lime, obtained on burning magnesian limestones, and by mixing with this product a certain quantity of crude carbolic acid, probably in the state of gas-tar. The theory of the action of this disinfecting powder is described by the inventor in the following words : — " The only agent we know which will decompose the noxious emanations from putrescent excreta, or other animal offal, without creating any detri- mental action upon those elements which we wish to preserve, is sulphurous acid. " Let us take two atoms of sulphuretted hydrogen, and one of sulphurous acid ; when they are brought into contact, tliey are mutually decomposed, and form three of sulphur and two of water, both of which are entirely odour- less. A similar reaction will ensue if we put phosphoretted hydrogen in the place of sulphuretted hydrogen, only the products would be two of phos- phorus, one of sulphur, and two of water as before, both of which are also entirely odourless. " Here, then, we have the means of solving the first condition of the pro- blem. By the agency of sulphurous acid the offensive smell of putrescent substances may be removed. Further than this, sulphurous acid has a conservative action, which is highly favourable to our object. It has a strong affinity for oxygen, and will not permit other substances in its presence to combine with oxygen till its own affinity is satisfied. It thus exercises an influence highly anti-putrescent, besides decomposing the offensive compounds which have been already formed. " We have another guarantee, however, for the prevention of putrefactive fermentation ; this is the carbolic acid, which has the property of coagulating albuminous substances, and generally of preventing putrescence. As it is a liquid oily compound, we combine it with lime, and are thus enabled to dry it and reduce it to a powder, so rendering its application easy and simple. " It only remains now that I explain the reason why we use magnesia in combination with the sulphurous acid. The reason is, that the compounds to be preserved are ammonia and phosphoric acid, and magnesia is the only available element which combines with them both and forms a triple com- pound, perhaps of all other possible combinations the best for agricultural pur- poses, viz. the triple phosphate of magnesia and ammonia. " In the treatment of sewage or other similar matter in an advanced stage of decomposition, containing any considerable percentage of ammonia, we find it advantageous to add a soluble phosphate, as the quantity of phosphoric acid in the substances to be operated upon is not, in the circumstances, sufficient to permit the formation of the triple phosphate. " Thus, then, we use sulphurous acid to remove the offensive smell, car- bolic acid to prevent putrefactive fermentation, a little lime to neutralize and dry this latter acid, and magnesia to combine with and preserve the phosphoric acid and ammonia ; and, in special cases, we add a soluble phosphate to pre- vent the loss of any of the ammonia." Farmyard Manure. 17 These are Mr. M'Dougall's own words respecting the theory of the action of his disinfecting powder. The passage cited will be found (pp. 18, 19) in Mr. M^Dougall's pamphlet, entitled, * On the Preservation of the Natural Manures, by Alexander M'Dougall. 1856/ In page 20 of this pamphlet it is said — " Theoretically, it is perfect, leaving nothing to be desired; and in practice, it has not fallen short of the just expectations which were formed of its probable results in actual use." I regret that I cannot share this opinion, for Mr. M'Dougairs powder is neither theoretically perfect, nor does it answer in practice the purpose for which it is recommended to the notice of agriculturists, for it is destitute of the property of fixing any free ammonia in liquid manure or in dung-heaps. It is not my intention to criticise in detail Mr. M'DougaH's ** perfect theory, which leaves nothing to be desired ;" but I trust he will excuse me for reminding him that when two or more elements unite together chemically, a new compound sub- stance is produced, which possesses properties not shared by its constituents. Thus sulphuric acid uniting with lime produces sulphate of lime, a combination in which neither the most striking characters of sulphuric acid nor of lime are any longer perceptible. In the same manner sulphurous acid uniting chemically with lime produces a new compound substance, in which the most prominent features of lime and sulphurous acid have become permanently altered. Unless it can be shown experimentally that the action of sulphurous acid in combination with lime and magnesia upon sulphuretted or phosphoretted hydrogen is the same as that of free sulphurous acid, Mr. M'Dougall's attempted explanation of the action of the disinfecting powder upon sulphuretted and phosphoretted hydrogen must indeed be re- garded as a theory — a theory, however, which I imagine every sound chemist will more likely call a wild than a perfect one. M'Dougall's powder possesses the power, though only in a slight degree, of removing sulphuretted hydrogen from liquids. This property it owes not to the sulphite of lime or magnesia which it contains, but, as it appears to me with much greater probability, to the free lime which enters into the composition of M'Dougall's powder. In order to decide positively this point, the following experi- ment was made : — To a strong and clear solution of M'Dougall's powder in water a small quantity of sulphuretted hydrogen water was added ; the smell disappeared, no deposit of sulphur was pro- duced. Some more sulphuretted hydrogen water was added to 18 Farmyard Manure. the same liquid ; a strong smell of sulphuretted hydrogen re- mained, and no deposit whatever of sulphur was produced. The solution of the disinfecting powder in water had a distinct alkaline reaction, and contained, as ascertained by direct experi- ment, in addition to sulphite of lime and sulphite of magnesia, some quick lime. Lime-water, i.e. a solution of quick lime in water, I find pos- sesses the property of removing sulphuretted hydrogen from its solutions to a larger extent than a solution of M'Dougall's powder ; whilst a solution of pure sulphite of lime and magnesia apparently does not possess the power of removing sulphuretted hydrogen from its solution. At any rate, even a concentrated solution of sulphite of lime or sulphite of magnesia, added in large excess to a solution of sulphuretted hydrogen, produces no deposit of sulphur, and has no immediate effect upon this gas. Having proved experimentally that it is not the sulphite of lime or magnesia in M^Dougall's disinfecting powder, but in all probability the free-lime contained in it, which instantly removes sulphuretted hydrogen from its solutions in water, I will next describe some experiments which I have made in conjunction with Mr. Coleman, our farm-manager, with a view of testing the disinfecting properties of this powder. The fact that refuse gas-lime contains sulphurous acid in com- bination with lime, as well as free lime, induced me to compare the effects of M/Dougall's powder with dried and finely pow- dered gas-lime, to which a small quantity of gas-tar was added. By incorporating some gas-tar with the refuse lime of gas-works, previously dried and powdered, a product is obtained which smells very similar to M'Dougall's powder, and resembles the latter closely in its general appearance; and also so far in com- position, as it contains likewise sulphite of lime, free lime, and carbolic acid. The proportion of caustic lime in this pre- pared gas-lime, however, was much more considerable than in M'Dougall's powder, which no doubt accounts for the fact that this sample of prepared gas-lime greatly excelled the newly- invented powder in deodorizing properties. It appeared to me also desirable to mix slaked lime with a little gas-tar, and to try this mixture simultaneously with the two other powders in the stable. With these three powders the following experiments were made : — 1st Set of Experiments. Three loose boxes were cleared out and respectively sprinkled with M'Dougall's powder, prepared gas-lime and tar, and with slaked lime and tar. Farmyard Manure. 19 All animal smell was instantly removed in each of the three boxes, but there remained a faint but perceptible smell of am- monia in the first box, sprinkled with M'Dougall's powder. In the second box, sprinkled with gas-lime, the smell of ammonia was still more distinct ; and in the third box, sprinkled with slaked lime, the smell of ammonia was most marked. It thus appears from these experiments that whilst all three powders removed instantly the peculiar animal smell which pre- vails in stables, none possessed the power of fixing free ammonia. In the experiment with M'Dougall's powder the smell of ammonia was masked by the tarry products contained in this powder to an extent which rendered it difficult to an inexpe- rienced person to recognise by the smell alone the presence of free ammonia. On the other hand, the smell of ammonia in the third loose box was decidedly stronger after sprinkling the floor with slaked lime and tar than before the experiment. As M'Dougall's powder contains only little caustic lime, the pre- pared lime a good deal more, and the slaked lime most caustic lime, it is evident that the differences in this respect are mainly due to the relative quantities of caustic lime present in the three experimental powders. The experiment with slaked lime, more- over, shows that the excrementitious matters on the floor of stables contain ammoniacal salts, from which ammonia is libe- rated by caustic lime. 'ind Set of Experiments. Some of M'Dougall's powder was next added to fresh farm- yard manure. The peculiar animal smell of the latter was rapidly removed, but ammonia — it is true, in small quantities, but still in a perceptible degree — liberated at the same time. An equal portion of fresh farmyard manure was treated with prepared gas-lime, and a third portion of fresh dung with slaked lime and gas-tar. The two last-named powders rapidly destroyed the disagree- able animal smell of the dung, and, like M'Dougall's powder, liberated some ammonia. Similar experiments were tried with three equal portions of well rotten dung with similar results. In each case ammonia was given off in small quantities, especially in the experiment in which slaked lime was added to rotten dung. In order to leave no doubt on the fact brought out by our ex- periments on fresh and rotten dung, namely, that M'Dougall's powder, instead of fixing ammonia, actually liberated ammonia from its combinations, the following experiments were made : — A portion of rotten dung was put into a wide-mouthed bottle, in the neck of which a moistened red litmus paper was 20 Farmyard Manure. inserted. At the same time an equal quantity of rotten dung was put into a second bottle, and some of M^Dougall's pow- der was well mixed with the dung. The animal smell, as before, was completely removed. In the neck of the second bottle a red litmus paper was inserted. In the course of a few minutes the litmus paper in contact with the air surrounding the deodo- rized dung was distinctly turned blue, whilst the paper in the first bottle retained its original red colour, thus proving clearly that the dung which contains no free ammonia, when deodorized with M'Dougall's powder, gives off ammonia in a perceptible degree. I have shown in numerous experiments that the amount of ammonia which may be obtained by treating farmyard manure with quick lime is but small ; unmixed with any other animal emanations, when gradually liberated by a powder which, like M'Dougairs, contains only little caustic lime, and masked by the smell of tar, the ammonia in dung is hardly perceptible by the smell. And as many people refer the smell of dung to ammonia, forgetting that the peculiar putrescent smell of dung is princi- pally due to other animal exhalations, I can readily understand the mistaken idea which no doubt many entertain who have practically tested the effects of this disinfecting powder upon dung. But let them try the effect of M'Dougall's powder upon a solution of sal-ammoniac or sulphate of ammonia, and they will find, without difficulty, that it liberates from these inodorous salts the pungent-smelling ammonia. Or, by mixing a moderate quantity of the powder with a manure whicli, like guano, contains a large proportion of ammoniacal salts, it may be shown that M'Dougall's powder contains a constituent, the chemical effect of which manifests itself by the copious discharge of ammonia. ^rd Set of Experiments. In a third series of experiments I have studied the disinfecting properties of M'Dougall's powder in relation to liquid manure. With a view of ascertaining what share the sulphite of mag- nesia and sulphite of lime had iii the deodorizing effect upon liquid manure, and what share the free lime contained in the powder, I prepared a pure and concentrated solution of sulphite of lime and sulphite of magnesia, the effects of which were tried upon liquid manure. For other experiments I used a solution of gas-lime, prepared as described above, and I also tried the effects of slaked lime mixed with some coal-tar. Finally, I saturated the free lime in M'Dougall's powder, by passing into it sulphurous acid as long as it was absorbed, and Farmyard Manure. 21 lomovod t]ie excess of this gas by drying the powder at a very moderate heat. With these various materials, the following experiments were instituted : — 1. Added to 6 ounces of liquid manure 2 ounces of a strong solution of sulphite of magnesia and sulphite of lime. No apparent effect was produced. Added 2 more ounces of the same solution. The smell remained unchanged. I^y keeping this mixture of liquid manure with sulphite of magnesia and lime, for three weeks in a bottle, the original dis- agreeable smell of the liquid manure remained unaltered, thus showing that pure sulphites have not the power of removing the bad smell from putrescent liquids. 2. 50 grains of M'Dougall's powder were finely pounded in a mortar, and gradually mixed with 5 ounces of liquid manure. The bad smell of the latter disappeared instantly. An addition of 5 ounces more of liquid manure ; the liquid became sweet to the smell after a few minutes. 10 additional ounces were next mixed with the disinfected liquid, and thus altogether 20 ounces of liquid manure were mixed with 50 grains of M'Dougall's powder. After some time the bad smell disappeared altogether, but, at the same time, ammonia was set free, as shown by litmus paper suspended in the neck of the bottle. 3. The same experiment was tried, with the substitution for M'DougalFs powder of 50 grains of prepared gas-lime. The result was similar to that obtained in the second experi- ment ; the only perceptible difference being that, by using gas- lime, the liquid manure, which had originally a dark greenish brown colour, was rendered more transparent and lighter coloured than by using M'Dougall's powder. 4. Another experiment was tried with 20 ounces of liquid manure and 50 grains of slaked lime, mixed with some gas-tar. The putrescent smell was instantly removed, and the liquid became bright and colourless like water. Ammonia was given off. 5. i lb. of M'Dougall's powder was treated with 20 ounces of distilled water, and filtered. The clear liquid was coloured yellow, smelt like the powder, and had a weak alkaline reaction. 4 ounces of this solution were mixed with 4 ounces of liquid manure ; the bad smell disappeared after some time. 4 ounces more of liquid manure were added ; the smell was not entirely removed. Kept in a bottle for 2 days, the liquid was not entirely deodorized. 22 Farmyard Manure, 6. i lb. of prepared gas-lime was treated with 20 ounces of distilled water. The clear liquid filtered from the insoluble matter was yellow-coloured, and smelt similar to the solution of M'Dougall's powder. It possessed a stronger alkaline reaction than the solution of M'Dougall's powder. By mixing 8 ounces of liquid manure with 4 ounces of this solution of gas-lime a considerable deposit was produced, the liquid became much clearer and brighter, and lost all disagreeable smell. 7. 6 ounces of liquid manure were mixed with 20 grains of M'Dougall's disinfecting powder. The colour of the liquid became lighter, ammonia was liberated, and the peculiar disagreeable odour of liquid manure completely removed after some time. 8. 6 ounces of liquid manure were mixed with 20 grains of M'Dougall's powder, previously saturated with sulphurous acid. The colour of the liquid remained unaltered, and the smell remained as bad as before the addition of the powder. If the deodorizing effects of the disinfecting powder were due to the sulphite of magnesia contained in it, the deodorizing effect of the powder when saturated with sulphurous acid, it is plain, should have become more marked ; but the contrary was the case. Indeed, by neutralizing the free alkaline constituents in the powder its deodorizing power was destroyed. 9. It is but fair to state that Mr. M'Dougall recommends the addition of a soluble phosphate to liquids containing much free ammonia. He mentions liquid manure and sewage as two liquids which do not contain sufficient phosphoric acid in a soluble form to unite with all the ammonia contained in these liquids and the magnesia of the disinfecting powder. Following his advice, I added to liquid manure phosphate of soda, in various proportions, and used small and large doses of the disinfecting powder. In every instance M'Dougall's powder failed to fix the ammonia in liquid manure, notwithstanding the presence of abundance of soluble phosphates. It thus appears from these various experiments : — 1. That M'Dougall's powder is unfit to fix any ammonia in dung. 2. That its deodorizing effects are not due to the sulphite of magnesia or sulphite of lime, but to the alkaline constituents which it contains. 3 That, instead of fixing ammonia, it liberates, like all alka- line matters, ammonia from its combinations. It is well known, however, that animal excrementitious matters, when deodorized by lime, after some time give off again Farmyard Manure, 23 a disagreeable odour ; and it is very likely that sulphite of ma<2:- nesia and sulphite of lime, on account of their great affinity for oxygen, will prevent this evil by stopping the further decompo- sition of animal matters deodorized by lime. Considered in a purely sanitary point of view, M'Dougall's powder may there- fore possess advantages over quick lime as a disinfectant. Still it is difficult to conceive how such a farther decomposition can be arrested practically by the use of this powder, for it appears to me that this can only be realized by the employment of so large a quantity of powder as to render the process altogether too expensive. Drainings of Dung-heaps. — Nobody can deny that farmyard manure is seldom kept in the most efficient manner. In many places in England, especially in Devonshire and in some parts of Gloucestershire, it is a common practice to place manure- heaps by the roadside, often on sloping ground, and to keep these loosely-erected heaps for a considerable length of time before carting the dung on the field. On other farms, the manure is allowed to remain loosely scattered about in uncovered yards for months before it is removed. Heavy showers of rain falling on manure kept in such a manner, by washing out the soluble fertilizing constituents of dung, necessarily greatly deteriorate its value. It is well known that the more or less dark-coloured liquids which flow from badly-kept dung-heaps in rainy weather possess high fertilizing properties. According to the rain which falls at the time of collecting these drainings, according to the character of the manure, and similar modifying circumstances, the composition of the drainings from dung-heaps is necessarily subject to great variations. The general character of these liquids, however, is the same in dilute and in concentrated drainings. Several samples of dung-drainings were recently examined by me, and, from their analyses, it will .be seen that they contain a variety of fertilizing constituents which it is most desirable to retain in dung-heaps. The first liquid examined was collected from a dung-heap composed of well-rotten horse-dung, manure from fattening beasts, and the dung from sheep-pens. Both the horse-dung and dung from fattening beasts were made in boxes. The liquid which ran from this dung-heap was collected in rainy weather, and contained, no doubt, in addition to the liquid portion of the dung, a good deal of rain. The colour of this liquid was dark brown ; it contained no free sulphuretted hydrogen, nor any free ammonia. Its reaction was neutral to test-paper, but on boiling it became alkaline, ammonia being given off freely. Besides ammonia, boiling expelled a very considerable quantity of carbonic acid, which is o2 24 Farmyard Manure. contained in drainings of dung-heaps, partly in mechanical solu- tion, but chiefly in the form of bi-carbonates ; these, on boiling, are decomposed into neutral carbonates, and into carbonic acid, which escapes. On addition of hydrochloric acid the liquid strongly effervesced and gave off a most disgusting stench. Notwithstanding the disagreeable odour produced, on adding hydrochloric acid to these drainings of a dung-heap, there was no sulphuretted hydro- gen in the mixed gases which escaped. The acidulated liquid being heated deposited in abundance a dark brown flaky sub- stance, which was afterwards identified as a mixture of humic and ulmic acids. The deposition of these organic acids in the shape of a brown flaky mass had the effect of leaving the super- natant liquid merely pale yellow. It is thus plain that the dark brown colour of drainings of dung-heaps is due to compounds of humic and ulmic acids. These compounds are easily decom- posed by mineral acids, and as the dark-coloured organic acids, which separate, in a free state are nearly insoluble in water, the original dark brown liquid is decolourized. Humic and ulmic acid are both products of tlie decay of car- bonaceous organic matters, and their abundance in the drainings of dung-heaps is easily explained by the decomposition of the straw and the non-nitrofjenized constituents of excrementitious matters. In combination with potash, soda, and ammonia, humic and ulmic acids form dark -colon red, readily-soluble salts ; whilst with lime, magnesia, and earthy and metallic bases the same organic acids form compounds insoluble in water. The dark brown colour of the drainings therefore is an indirect proof of the existence in them of potash, soda, or ammonia. The subsequent examination indeed has afforded the direct proof that drainings of dung-heaps contain all three alkalies, combined at least in part with organic acids, which being found in large quan- tities in humus may be called by the generic name of humus- acids. Chemists are well acquainted with the fact that with the degree of heat to which chemical agents are exposed their affinities one towards the other are changed. Thus, for instance, at the ordinary temperature of the atmosphere, or at the heat of boiling water, sulphuric acid is capable of separating phosphoric acid from bone-earth, and forming with the lime of the latter sulphate of lime or gypsum. But when a mixture of sulphate of lime and phosphoric acid is heated to redness, the affinities between lime and phosphoric and sulphuric acid are changed. A reverse action to that which takes place at a comparatively low temperature manifests itself, and, provided the temperature is sufficiently elevated and enough phosphoric acid present, all Farmyard Manure. 25 sulphuric acid is driven out from the gypsum, and phosphoric acid takes its place. Similar chemical reactions, dependent on changes of tempera- ture, are continually taking place in dung-heaps in an active state of fermentation, as well as called into play by heating drainings of dung-heaps. I have kept for days a reddened litmus-paper inserted into the neck of a bottle, in which such drainings were placed, without perceiving the slightest change in the colour of the paper, thus proving distinctly that these drainings do not contain a trace of free ammonia. But when the temperature of the drainings is slightly elevated ammonia is given off at once, and continues to escape as long as the liquid is kept boiling, and a good deal of water is left in the vessel in which the liquid is boiled. For this reason it is necessary in determinations of free ammonia in this and similar liquids containing humus-acids, to continue the process of distillation until the liquid is nearly evaporated to dryness. In boiling the drainings of dung-heaps the volatiliza- tion of ammonia is accompanied by the deposition of flakes of humic and ulmic acids, as well as carbonate of lime, held in solution by carbonic acid,, which in boiling is likewise expelled. It thus appears that although the affinity of humus acids for ammonia is sufficiently strong completely to prevent its escape at the ordinary temperature, it suffers a change at a slightly elevated temperature, in consequence of which ammonia escapes. Drainings of dung-heaps contain in solution bi-car- bonate of lime, which, at the ordinary temperature of the air, has no effect upon humate and ulmate of ammonia ; on heating, the bi-carbonate of lime loses carbonic acid, and becomes neutral car- bonate of lime, a combination which is capable of decomposing humates and ulmates of ammonia. The ulmic and humic acid of the latter uniting with the lime, with which they form insoluble compounds, leave the ammonia in a free state, and on boiling of liquid it gradually evaporates with the watery vapours. The examination of the chemical constitution of the drainings of dung-heaps thus leads at once to the explanati(m of the reason why hot dung has a pungent smell, caused by the escape of ammonia, and why even rotten dung when cold does not give off any free ammonia. In relation to the amount of ammonia farm- yard manure always contains a great excess of these humus acids, hence the free ammonia proceeding from the interior portions of dung-heaps, which are in an active state of fermentation, is arrested by the humus substances contained in the cold external layers of dung-heaps. In contact with air any undccomposed 26 Farmyard ManurCi straw is gradually changed into these excellent fixers of ammonia, and thus a natural provision is made in dung-heaps to prevent the loss of ammonia. Drainings of dung-heaps present us with another interesting chemical particular, which at first sight appears quite anomalous, but which finds a ready explanation in the peculiar composition of these drainings and the properties of humus and ulmic acid. Drainings of dung-heaps, namely, present us with a liquid which, though perfectly neutral to test-paper, may be mixed with a certain quantity of acid without becoming in the slightest degree acid. This will appear from the following experiment : — 7000 grains of perfectly clear, dark-brown coloured and neutral drainings were mixed with 50 drops of concentrated hydro- chloric acid ; the liquid strongly effervesced, gave off a horrid smell, and deposited a considerable quantity of a brown, flaky substance. The supernatant liquid was much paler, and pro- duced no change on litmus paper. A single drop of concentrated hydrochloric acid added to 7000 grains of distilled water was readily detected by turning blue litmus paper distinctly red, thus proving that the test-paper was sufficiently delicate to detect the presence of a very small quantity of free acid. A further addition of 50 drops of concentrated hydrochloric acid to the same drainings produced a decided acid reaction, and caused the separation of a little more flakulent matter. The whole of the brown flaky substance was collected in a weighed filter, dried at 212° Fahr., and weighed, and found to amount to 12*55 grains. An imperial gallon of these drainings accordingly contained 125*5 grs. of humic and ulmic acids. If it be remembered that these organic acids are insoluble in water, and are contained in the drainings in combination with alkalies, the curious circumstance that an acid may be added to neutral drainings without producing an acid reaction will be readily understood. The first quantity of hydrochloric acid had the effect of uniting with the alkalies, and it thus became neutralized, whilst the organic humus acids previously in union with the alkalies of the drainings were separated, and, being insoluble in water, of course could not affect litmus paper. I have determined also in the same drainings the amount of carbonic acid which is expelled by simply boiling this liquid, and found in one imperial gallon of drainings 88*20 grains of carbonic acid, which is thus loosely united with the liquid. The amount of free ammonia (ammonia expelled on boiling the liquid) in these drainings was determined in the manner Farmyard Manure. 2 7 described above ; and after the free ammonia was removed, quick lime was added to the remainder of the concentrated liquid for the purpose of separating any ammonia present in the form of salts, which are not decomposed simply by boiling. In this way the following results were obtained : — One imperial gallon of drainings c(mtained 36'25 grains of free ammonia and 3*11 grains of ammonia in the form of salts, not decomposed simply on boiling, but by continued boiling with quick lime. Evaporated to dryness, 7000 grains furnished 6251 grains of solid matters, dried at 212^ Fahr,; or one imperial gallon was found to contain 625*10 grains of solid matters. On heat- ing to redness, 62*51 grains left 3689 grains of ash. This ash was submitted to a detailed analysis, and calculated for one imperial gallon of the drainings. According to the analytical results obtained in these different determinations, an imperial gallon of these drainings contained — Yolatile and combustible constituents 395"66 Ammonia driven out on boiling .. .. 36'25 i Together. Ammonia in the state of salts decomposed i 39"36 by quick lime 3'11 J Ulmic and humic acid 125*50 Carbonic acid, expelled on boiling 88*20 Other organic matters (containing 3*59 of nitrogen) 142'60 Viz. 395*66 Viz. ( Mineral matters (ash) 368*98 'Soluble silica .. 1*50 Phosphate of lime, with a little phosphate of iron .. 15-81 Carbonate of lime 34*91 „ magnesia 25'66 Sulphate of lime 4*36 Chloride of sodium .. 45*70 „ potassium « .. 70*50 ^Carbonate of potash 170*54 368*98 Total per gallon 764*64 These analytical results suggest the following remarks : — 1. It will be seen that these drainings contain a good deal of ammonia, which should not be allowed to run to waste. 2. They also contain phosphate of lime, a constituent not present in the urine of animals. The fermentation of the dung- heap thus brings a portion of the phosphates contained in manure into a soluble state, and enables them to be washed out by any watery liquid that comes in contact with them. 3. Drainings of dung-heaps are rich in alkaline salts, especially in the more valuable salts of potash. 28 Farmyard Manure. 4. By allowing the washings of dang-heaps to run to waste, not only ammonia is lost, but also much soluble organic matter, salts of potash and other inorganic substances, which enter into the composition of our crops, and which are necessary to their growth. II. Drainings from another Dung-heap. These drainings were not so dark-coloured as the preceding ones. Like the former liquid, it was neutral, but gave off ammonia on boiling and on addition of quick lime. Hydrochloric acid produced a dark-brown coloured flaky deposit, leaving the liquid only pale yellow. The amount of the precipitated humus acids was much smaller than in the preceding liquid. For want of a sufficient quantity of liquid, only the amount of solid matter contained in it could be determined. An imperial gallon on evaporation furnished 353*36 grains of solid ma^tter, dried at 212° Fahr. III. Drainings from a third Dung~heap» A dung-heap, composed chiefly of mixed fresh horse, cow's or pig's dung, furnisliedthe material for the third analysis of drainings. This liquid was much darker than the two preceding liquitls, possessed an offensive smell, although it contained no sulphu- retted hydrogen. It was neutral to test-paper, consequently did not contain any free or carbonate of ammonia. On heating, am- monia escaped, apparently, however, in much smaller quantities than from the preceding drainings. This liquid was collected at a time when no rain had fallen for several weeks, which circumstance accounts for its greater concentration. It was submitted to the same course of analysis as the first drainings. 7000 grs. evaporated to dryness produced 135*774 grs. of dry matters; and this quantity, on burning in a platinum dish, fur- nished 62*58 grs. of mineral matters. A separate portion was used for the determination of the amount of ammonia present in the form of salts ; and another portion of liquid, acidulated with a little hydrochloric acid evaporated to dryness, was employed for the determination of the whole amount of nitrogen. By deducting the amount of nitrogen found in the ammoniacal salts from the total amount of nitrogen obtained by combustion of the solid matter with soda-lime, the proportion of nitrogen contained in the organic substances of these drainings was ascertained. The following Table represents the composition of the Solid Farmyard Manure. 29 substances found in one imperial gallon of drainings from fi'esli manure : — Composition of Solid Matters in one Gallon of Drainings from Fresh Farm- yard Manure. Ready-formed ammonia (principally present ] i^oq as liumate and iilmate of ammonia) . . ) * Organic matters 716'81 * * Inorganic matters (ash) 625'80 Total amount of solid matter in one gallon\ -, orrj.-jA of drainings | lrfo7 74 Containing nitrogen 31*08 Equal to ammonia 37'73 ♦ * 625-80 of ash consisted of:— Silica 9-51 Phosphates of lime and iron 72*65 Carbonate of lime 59*58 Sulphate of lime 14*27 Carbonate of magnesia 9*95 potash 297-38 Chloride of potassium 60-64 ' „ sodium 101-82 It will be observed that these drainings contain about double the amount of solid matter which was found in the liquid from the first heap. The composition of this solid matter compared with that of the solid matter in the liquid from the first heap, moreover, presents us with some particulars to which it may be advisable briefly to allude. In the first place I would remark that notwithstanding the greater concentration of the third liquid, as compared with the first, the proportion of ammonia present in the form of ammoniacal salts is less than one-half; for whilst the first drainings contained in the gallon 39 grs. of ready-formed, ammonia in round numbers, the third drainings contained only 15 grs. per gallon. It thus appears that drainings from manure-heaps in an ad- vanced stage of decomposition contained, as may be naturally expected, a larger proportion of ready-formed ammonia than the liquid which flows from heaps composed of fresh dung. It is further worthy of notice that the first drainings contained nearly all the nitrogen in the form of ammoniacal salts, whilst the drainings from fresh dung contained the larger proportion of this element in the form of soluble organic substances. The most important constituent of farmyard manure, i.e., nitrogen, thus is liable to be wasted in the drainings, whether they proceed from rotten or fresh manure, for in either case it passes off in a soluble state of combination. Whilst speaking of the nitrogen in the drainings of dungheaps I ought to mention that in both the liquids examined in detail I 30 Farmyard Manure. have detected readily the presence of nitric acid. In the liquid from fresh manure there were apparently mere traces of nitrates, but in that from rotten dung the proportion of nitric acid was so considerable that I hoped to be able to determine it quantita- tively. But I found the large amount of soluble organic matter to interfere sadly with the nitric acid determination ; and, unable to supply for the present correct results, I merely mention the fact that these liquids contained nitrates, and trust to be able to supply this deficiency in these analyses at a future period. In the next place I would observe that the proportion of organic and inorganic matters bear to each other a different rela- tion in the first and in the third liquid. In the liquid from rotten dung the proportion of mineral matter exceeds that of organic substances, and in the third liquid the reverse is the case. We learn from this that soluble organic matters are very liable to become decomposed ; and it is not unlikely that all putrescent organic matters before assuming a gaseous state are first changed into soluble matters. In the first stage of decomposition, z. e., during the active fer- mentation of dung, the constituents of farmyard manure are ren- dered more and more soluble ; hence, up to a certain point the amount of soluble organic matters increases in manures. But when active fermentation in manure heaps becomes gradually less and less energetic, and finally ceases, the remaining fer- mented manure is still liable to great and important changes, for it is subject to that slow but steady oxidation, or slow combus- tion, which has been termed, appropriately, by Liebig, Erema- causis. To this process of slow oxidation all organic substances are more or less subject. It is a gradual combustion, which ter- minates with their final destruction. Hence the larger proportion of organic matter in the liquid from the manure heap formed of fresh dung, in an active state of fermentation, and the smaller proportion of organic matter in the drainings of the first heap, in which the dung had passed the first stage of decomposition, and been exposed for a considerable period to the subsequent process of cremacausis, or slow com- bustion. The formation of nitric acid from putrefying organic matters has long been observed, but the exact conditions under which it proceeds are by no means satisfactorily established, and much room is left to further extended investigations. The mineral substances in the drainings from fresh dung are the same as those from rotten. Like the ash of the latter, the liquid from fresh dung-heaps contains soluble phosphates, soluble silica, and is rich in alkaline salts, especially in carbonate of potash, of which there are nearly 300 grs. in a gallon of the liquid. Farmyard Manure. 31 Sufficient evidence is thus presented in the analyses of these liquids, that, as the drainings of both fresh and rotten dung- heaps are allowed to flow into the next ditch, concentrated solutions of the most valuable constituents of dung are carelessly wasted. With a view of preventing such a serious loss, I have sug- gested the propriety of carting the manure on the fields, when- ever practicable, in a fresh state, and of spreading it at once. It may be objected that the application of manure in a fresh state, equivalent to winter manuring, and especially the spreading of dung, will lead to waste, inasmuch as the rain which falls during the winter and spring has much more chance of washing out fertilizing substances from dung than by applying it at the time of sowing. This objection would indeed be a valid one, if we were not acquainted with the fact that all soils containing a moderate proportion of clay possess the property of retaining the more valuable constituents of manure ; but, this being the case, the objection on these grounds cannot be admitted. With more force, however, it may be made with reference to light sandy soils, and it is indeed upon such soils that manure is best applied in spring. 1 would remind the reader of the interesting and important observations of Mr. Thompson with respect to the property of soils of absorbing manuring matters,* and beg to refer him to the highly important investigations of Professor Way on the same subject. The papers of Professor Way on this subject are full of interest ; they embody highly important results, and constitute, most valuable contributions to our agricultural literature. A careful perusal of these papers will afford* strong evidence that soils not merely possess the power of absorbing and retaining gaseous ammonia, but that they also have the property of sepa- rating this fertilizer, as well as potash and other manuring matters, from their soluble combinations. Professor Way principally operated with simple salts, and it may therefore be urged, with some plausibility, that, in the case of a highly complex mixture of soluble substances, such as that presented in the liquid portion of manure, changes may take place in the soil which lead to a waste of manure, when applied long before the crop is sown which it is intended to benefit. Thus it may be urged that it by no means follows that because a soil absorbs ammonia when a solution of sulphate of ammonia is passed through it, the same absorption will take place when an ammoniacal salt, mixed with some dozen of other substances, is passed through it. ♦ Journal of the Royal Agricultural Society, vol. xi. p. 68. 32 Farmyard Manure. Fully impressed with the force of such an argument, 1 was anxious to determine, by direct experiments, the changes which liquids like the drainings of dung-heaps and liquid manure undergo when brought into contact with soils, and to ascertain at the same time to what extent soils of known composition pos- sessed the power of absorbing manuring matters from such com- plex liquids. It is hardly necessary to observe that the results to which the experiments to be described presently have led, apply not merely to the liquids experimented with, but extend to compound manuring matters in general and to farmyard manure in particular, for the drainings of dung-heaps may, indeed, be regarded as the very essence of dung. The deductions which can be legitimately drawn from my experiments, therefore, apply in a special manner to farmyard manure. In order to ascertain to what extent various soils possessed the power of absorbing manuring constituents from the drainings of dung-heaps, I determined to employ a limited quantity of soil and a large excess of liquid. To this end, 2 parts by weight of liquid were well mixed with 1 part by weight of soil, and left in contact with the latter for 24 hours, after which the clear liquid was drawn off and passed through a filter. Experiments to ascertain the Extent of Absorbing Properties of Soils of known Composition. 1. Experiment made with the Drainings of Dung-heaps com- posed of rotten Dung. — The drainings employed in this experi- ment were the same which contained in the imperial gallon 664'64 grains of solid matters, the detailed composition of which is given above. The composition of the soil used in the expe- riment is given below. The surface-soil contained a good deal of organic matter, a fair proportion of clay, little sand, and a moderate proportion of carbonate of lime in the form of small fragments of limestone. It was a stiffish soil, belonging to the clay-marls. Its subsoil was richer in clay and of a more compact texture and less friable character than the surface-soil. The mechanical analyses of soil and subsoil gave the following results : — Sarface-soiL SubsoiL Moisture when analysed 5-36 3*66 Organic matter and water of combination .. 25*86 8-79 Lime 14-30 26*03 Clay 34*84 56*76 Sand 19*64 4*76 100*00 100-00 Farmyard Manure. 33 In the chemical analysis of this soil the following results were obtained : — Surface-soiL Subsoil. Moisture when analysed 5*36 3*66 Organic matter and water of combination . . 25-86 8*79 Oxides of iron and alumina 13*88 10*13 Carbonate of lime 14*30 26*03 Sulphate of lime '56 Not determined. Phosphoric acid and chlorine traces Carbonate of magnesia 1*04 | Potash -07 \ 1*67 Soda •. '18) Insoluble siliceous matter 38*75 49*73 100-00 100*00 2000 grains of this soil and 2000 grains of subsoil were mixed with 4000 grains of the liquid from rotten dung. After 24 hours the clear liquid was carefully drawn off and filtered. Its original dark brown colour was changed into a pale yellow colour. This soil thus possessed in a high degree the property of decolourizing dark-coloured liquids like the washings of dung- heaps. 1200 grains of the filtered liquid, passed through soil, were distilled in a retort nearly to dryness, and the ammonia whicli was given off carefully collected in an apparatus containing hydrochloric acid, and so constructed as to secure the perfect absorption of ammonia. The amount of chloride of ammonium obtained on evaporation of the acid liquid in the receiving-vessel was •(52 grains. Tliis gives for 1 imperial gallon of liquid passed through soil 11*49 grains of ammonia. Originally the drainings contained, per gallon .. ,. 39*36 After filtration through soil they contained, per gallon 11*49 Absorbed by 70,000 grains of soil .. .. 27*87 amm. 1000 grs. of this soil thus absorbed '396 of ammonia. On evaporation of another portion of the same liquid passed through soil, 1 imperial gallon of filtered drainings was found to contain : — 164*88 of organic matter. • 210*20 of inorganic matter. Before filtration through soil, the imperial gallon con- tained : — 268*10 grains of solid organic substances. 368*98 of mineral matters. A considerable quantity of both organic and mineral matters thus was removed from the liquid in contact with the soil. h. A similar experiment was made by diluting 4000 grains of 34 Farmyard Manure. the same drainings with 4000 grains of distilled water, and leaving this more dilute liquid in contact for 24 hours with 2000 grains of the same soil and 2000 of subsoil. The filtered liquid contained in the gallon : — Ammonia 6"91 Organic matters 118-50 Mineral matters 147'3G Total amount of solid matters in gallon .. 272'77 The 147*36 of mineral matters (ash) consisted of — Silica 2-38 Phosphates of lime and iron 1*54 Carbonate of lime 79*72 „ magnesia 6*17 Sulphate of lime 7*92 Chloride of sodium 18*90 „ potassium 26-44 Carbonate of potash 4*29 Originally the liquid employed in this experiment contained 19*68 grains of ammonia to the gallon. After passing through half its weight of soil it contained only 6*91 grains of ammonia. Consequently 12*77 were retained by 35,000 grains of soil, and 1000 grains of soil absorbed *365 grains of ammonia. This result, it will be seen, agrees closely with the first experi- ment, in which undiluted drainings were used, and ascertained that 1000 grains of the same soil absorbed -396 grains of am- monia. In both instances it was thus found that rather more than two- thirds of the amount of ammonia present in these drainings in the form of ammoniacal salts were retained by a very limited quantity of soil. I have purposely used a large amount of liquid in comparison with that of soil. If, under such conditions, the soil is capable of retaining two-thirds of the whole amount of ammonia present in a liquid like the one examined, it is not too much to expect that no ammonia whatever will be lost in practice by carting manure on the fields in autumn and spreading it at once. The quantity of soluble ammoniacal matters in a heavy dressing of the best dung does not amount to many pounds, and such a quantity, in relation to the weight of the soil ready to take up ammonia from the manure, is so insignificant that the most scru- pulous may rest satisfied that in a soil containing even a small proportion of clay no ammonia will be lost by dressing the fields in autumn. Other no less important changes than those referring to the absorption of ammonia will strike the reader to have taken place in these drainings left in contact with the soil. Farmyard Manure, 35 For better comparison's sake, I will give the composition of the drainings before and after passing through soil, and then make a few additional remarks which are suggested by such a comparison. Composition of Drainings from Rotten Dung. 1 imperial gallon contains — Before After Filtration Filtration throngh Soil. Ammonia (in the form of ammoniacal salts) 19*68 6*91 Organic matters ■. 134-05 118-50 Silica -75 2-38 Phosphates of lime and iron 7*90 1-54 Carbonate of lime 17*46 79*72 Sulphate of lime 2*18 7*92 Carbonate of magnesia 12*83 6*17 Chloride of sodium 22*85 18*90 „ potassium 35*25 26*44 Carbonate of potash 85*27 4*29 338*22 272*77 It will be observed that this liquid, in passing through the soil, has undergone a striking change. Leaving unnoticed several minor alterations in the composition of the original liquid, I would direct special attention to the very small proportion of carbonate of potash left in the drainings after contact with this soil. It will be seen that, out of 85 grains of potash contained in the original liquid, no less than 81 grains have been retained by the soil. This is a result of the greatest importance, inasmuch as it shows that the soil possesses, in a remarkable degree, the power of removing from highly-mixed manuring substances not only ammonia from ammoniacal salts, but also the no less important soluble potash compounds. According to this result, 1000 grains of soil absorb no less than 2-313 grains of carbonate of potash. But, in addition to car- bonate of potash, a considerable quantity of chloride of potas- sium is retained in this soil by passing the washings from rotten dung through it : for it will be observed that nearly 9 grains of this salt, or, in exact numbers, 8*81, were retained in the soil. The avidity of the soil for soluble salts of potash is the more remarkable, as it offers a striking contrast to the apparent indif- ference of this soil to absorb soda from its soluble combinations ; for it will be seen that the liquid, after filtration through the soil, contains only about 4 grains less of common salt in the gallon than before filtration. In a purely chemical point of view, soda salts are closely allied to salts of potash, and yet there is a marked difference observable in the power of this soil, at least, to absorb the one or the other alkali. 36 Farmyard Manure. As regards the practical effect which salts of soda an