COiaNET-BETOK JIFICIAL STOXE. FRANKLIN INSTITUTE LIBRARY PHILADELPHIA Class. B.3.1,.5.. Book.Q.4.i Accession^ 3 6.0. comprising such works as, trom their rarity or value, saouia not be lent U^Arl 7^7"*^ periodicals, and such text books as ought to be LSd n a library of reference, except when required by Committees of the Institute or by Members or holders of second class stock, who have Xained the inTntd t^ircSrir^^- ^^^^^^ ^^^^ include wtit: Article VI.-The Secretary shall have authority to loan to M^bers and to holders of second^ class stock, any work belonging to the skX c'Ls subject to the following regulations : b « sm,to class, n„f.f nl^"^"" individual shall be permitted to have more than two books Sers of tL n ' T"''' permission, signed by at least two mem- bers of the Library Committee; nor shall a book be kept out more than TWO weeks; but if no one has applied for it, the former borr^er may ";iSen?e'^"^' ^~ '^^^ S ^^^^ :^^:^l^^-.^.^l^r'' borrower XTS J^fon 3.-Should any book be returned injured, the borrower shall pa v for the injury, or replace the book, as the Library CommitteeTay d reS and If one or more books belonging td a set or sets, be lost, the borrowe; shall replace them or make full restitution. sorrower ^ Article ^II.-Any person removing from the Hall, without permission from the proper authorities, any book, newspaper, or other pJo^erty in charge of the Library Committee, shall be reported to the CommUtee who may inflict any fine not exceeding twenty-five dollars. ^"™°i"^ee, who Article VIII No Member or holder of second class stock whose annual contribution for the current year shall be unpaid or who^« in ju-rears for fines, shall be entitled to d privileges ofThnlbr^ry" r^Rel" n/n?'r'? ]^ ~^^ Memhev or holder of second class stock, shall refuse or neglect to comply with the foregoing rules, it shall be the duty of the Secretary to report him to the Committee on the Library. ^ Article X -Any Member or holder of second class stock, detected in mu ilating the newspapers, pamphlets or books belonging to the InSte sti; b': Se^ubli^''^ '''''' -^-^-^^^P' of the offeLde; PEACTICAL TREATISE ON COiaNET-BETON AND OTHER ARTIFICIAL STONE. By Q. a. GILLMORE, MAJOR CORPS OF ENGINEERS, BREVET MAJOR-GE.VERAL, U. S. A. NEW YOKE : D. VAN NOSTEAND, PUBLISHEE, 23 Murray and 27 Warren Street. NOTE. The professional paper, entitled "Report on Beton Agglom6re," which forms the leading feature, and indeed furnishes the basis of this small treatise, embraces all the nine plates as given by their titles, and that portion of the text preceding paragraph 132. In preparing this edition for private circulation, descriptions of four other varieties of artificial stone, all more or less prominently before the public and therefore demanding notice, have been added, and the original index has been replaced by another covering the entire work, as thus modified and enlarged. Q. A. G. New Yokk, July, 1871. THE GETTY CENTER LIBRARY CONTENTS. Coignet-Beton page 1 to 73 Ransome's Silicious Conceete Stone page 73 to 83 The Fbear Aktieicial Stone page 84 to 87 The American Building Block (Foster's and Van Derbnrgh's Patents page 87 to 93 The Sobel Aktificial Stone (Union Stone Company, Boston, Mass. ) page 93 to 102 Poetland Stone page 102. PROFESSIONAL PAPERS, CORPS OP ENGINEERS, U. S. ARMY. No. 19. EEPOET ON BETON AGGLOMERE; OK, COIGNET-BETON THE* MATERflL'S'b'F Wh'iCH IT IS'mVdE, Q. A. GILLMORE, MAJOR CORPS OF ENGINEERS, BREVET MAJOR GENERAL U. S. A. WASHINGTON: aOVERNMENT PRINTINa OFFICE. 1871. PROFESSIONAL PAPERS OF THE CORPS OF ENGINEERS OF THE UNITED STATES ARMY, PUBLISHED BY AUTHORITY OF THE SECRETARY OF WAR. HEADQUARTERS CORPS OF ENGINEERS. 1871. LIST OF PLATES. Plate I.— Cuuves of strength of Portland Cement Mortars. n. The Malaxator ok Beton Mixer. III. — The Greyveldinger Mortar Mill. IV. — Details of the Vanne Aqueduct. v.— General View of the Vanne Aqueduct. VI.— General View of the Vanne Aqueduct. VII.— Cellar in B6ton AGOLOM^Rfi. Vni.— Sustaining wall in Beton agglom^r^. IX.— The Hoffmann Annular Kiln. BETON AGGLOMERE. MOETAR. 1. Calcareous mortar is compounded of one or more of the varieties of common lime, hydraulic lime, or hydraulic cement — natural or artificial — mixed with sand and water into a plastic condition. The degree of strength and hardness, and consequently the durability, attained by mortar in setting, is dependent on the quality of the lime or cement employed, the kind and quan- tity of sand, the method and degree of manipulation, and the position, with respect to moisture or dryness, in which it is subsequently placed. A mortar, of which the matrix is common lime only, will never harden under water, or to any considerable extent if kept in damp places, excluded from the air. A condition of con- stant humidity, on the contrary, is favorable to the indura- tion of all hydraulic mortars. CONCEETE OR BETON. 2. These terms, by no means originally synonymous, have be- come almost strictly so by usage. As generally received and understood in modern practice, they apply to any mixture of mortar, generally hj-draulic, with coarse materials, such as gravel, pebbles, shells, or fragments of tile, brick, or stone. Two or more of these coarse ingredients, or all of them, may be mixed together. The matrix of beton was formerly understood to possess hy- draulic energy, while that of concrete, being derived from com- mon lime, did not. A concrete, destitute of hydraulic energy, is seldom used in works of importance at the present day. As lime, or cement X3aste, or a combination of the two, is the cementing substance or matrix in mortar, so mortar itself occupies a similar relation to concrete or beton. The proportions of the ingredients, in either case, should be de- termined on the principle that the volume of matrix should 8 BfiTON AGGLOM£e£. always be someivhat in excess of the volume of voids in the mate- rials to be united, tlie excess being added as a precaution against imperfect manipulation. BETON AGGLOMfiRfi. 3. This name is given to a beton of very superior quality, or, more properly speaking, an artificial stone, of great strength and hardness, which has resulted from the experiments and researches, extending through many years, of M. Frangois Coignet, of Paris. The essential conditions which must be carefully observed in making this beton are as follows : First. Only materials of the first excellence of their kind, whether common or hydraulic lime, or hydraulic cement, can be used for the matrix. Second. The quantity of water must not exceed what is barely fsufficient to convert the matrix into a stilf, viscous paste. Third. The matrix must be incorporated with the solid ingre- dients by a thorough and prolonged mining or trituration, pro- ducing an artificial stone i)aste, decidedlj^ incoherent in char- acter until compacted by j)ressure, in which every grain of sand and gravel is comj^letely coated with a thin film of the paste. There must be no excess of paste when the matrix is common lime alone. With hydraulic lime this precaution is less im- portant, and with good cement it is unnecessary. Fourth. The beton or artificial stone is formed by thoroughly ramming the stone paste, in thin, successive layers, with iron- shod rammers. MATERIALS SUITABLE FOR BETON AGGLOMEKE. The materials employed in making this beton are as follows : 4. Sand. — The sand should be as clean as that ordinarily required for mortar, for stone or brick masonry of good quality. Sand containing 5 or 6 per cent, of clay may be used without washing, for common work, by ijroportionally increasing the amount of matrix. Either fine or coarse sand will answer, or, X^referably, a mixture of both, containing gravel as large as a small pea, and even a small proportion of pebbles as large as a hazel nut. There is an advantage in mixing several sizes together, in such proportion as shall reduce the volume of voids to a minimum. Coarse sand makes a harder and stronger beton than fine sand. The extremes to be avoided are a too ' ' v., . BfiTON AGGLOM^.:^^*. uiiniite subdivision and weakening of the ma*trix,4>y-the use of fine sand only, on the one hand, and an undue enlargement of the volume of voids, by the exclusive use of coarse sand, on the other. The silicious sands are considered the best, though all kinds are emx^loyed. When special results are desired in the way of strength, texture, or color, the sand should be selected accord- ingly. 5. Common or fat lime. — The lime should be air-slaked, or, better still, it may be slaked by aspersion with the minimum quantity of water that will reduce it to an impalpable j)owder. It should be passed through a fine wire screen to exclude all lumps, and used within a day or two after slaking, or else kept in boxes or barrels protected from the atmosphere. It is scarcely practicable, under ordinary circumstances, to employ fat lime alone as the matrix of beton agglomere, par- ticularly in monolithic constructions, in consequence of its tardy induration. Even when used in combination with hydraulic lime or cement it acts as a diluent. M. Coignet claims, with great confidence, if not with correct judgment, that good beton can be made with sand and fat lime alone, but it is not so employed in his artificial stone manufac- tory at St. Denis, and it is believed that all the Avorks exe- cuted in beton by the company of which he is the head have contained hydraulic lime or cement. Attempts to make beton of even average quality, without good hydraulic ingredients, have failed iu the United States ; and it is extremely doubt- ful whether any characteristic excellence can be attained, after the lapse of weeks or even months, by a mixture of this character. When a matrix of fat lime alone must be employed for want of a better material, the manipulation should be conducted with watchful care. The quantity of water must be limited strictly to what is necessary to convert the lime powder into a stiff paste; and of this paste only enough must be used to cover each grain of sand and gravel with a thin, impalpable coating. The other conditions of prolonged trituration and thorough ramming, already referred to, are common to all varieties of this beton. 0. Hydraulic lime. — The most suitable limes are, like those of Theil, Seilley, and other localities in France, derived from the argillaceous limestones, in contradistinction to the^magne- sian or argillo-magnesian varieties. These limestones contain 10 BfiTON AGGLOMfiEfi. before burning from 15 to 25 per cent. — generally less tlian 20 per cent.— of cla}^ After burning, the lime is slaked to powder by aspersion witb water, and sifted to exclude unslaked lumps. Hydraulic lime cannot be considered an essential ingredient of beton agglomere, except in comparison witli common lime. It may be altogetber replaced by good hydraulic cement, or it may be used alone, or mixed with common lime, to the entire exclusion of cement. A stiff paste of this lime should set in the air in from ten to fifteen hours, and sustain a wire point one-twenty-fourth of an inch in diameter, loaded with one pound, in eighteen to twenty-four hours. Its energy, and therefore its value, varies directly with the amount of clay which it contains, w^hich generally will not exceed 20 per cent, before burning, although it may reach 25 per cent. Beyond this point the burnt stone can seldom be reduced by slaking and becomes a cement. No hydraulic lime of this variety has ever been manufac- tured in the United States. It is not known that stone suit- able for it exists here. 7. Among hydraulic limes, those of Theil and Seilley, France, may be assumed as of fair average quality. They have been extensively used in the w^orks executed in beton agglomere, under the supervision of M. Coignet. Theil lime alone supplied the matrix of the betons used in the construction of the light-house and jetties at Port Said, Egypt. Its light color renders it suitable for statuary and works of ornamentation, in which the delicate shades of gray and drab are desirable. 8. Analysis of raw Theil limesone : Carbonate of lime 81.36 Carbonate of magnesia , 1.00 Clay , 14.90 Oxide of iron 1.70 Water and bitumen 1.10 9. The Theil hydraulic lime, slaked to an impalpable powder, weighs 71^ pounds to the struck United States bushel, when j)Oured into the measure loosely ; and 84^ jjounds, if compacted by shaking and jarring. Under the same condition, the Seilley lime weighs 54 pounds and 60 pounds, respectively. These weights were carefully determined from average samples taken from cargoes received in New York. 10. Portland Cement. — The heavy slow-setting Portland cements, natural or artificial, are the only ones suitable for beton BfiTON AGGLOMfiRE. 11 aggloniere. They are manufactured extensively throughout Europe. Among- the most noted works are those at Boulogne- Sur-Mer and Seilley, in France ; at Bieberich, Limburg, and Stettin, in Germany; at Dresden, in Saxony, and several in the neighborhood of London and Liverpool, England. This cement is produced by burning, with a heat of great in- tensity and duration, argillaceous limestones, containing from 20 to 22 per cent, of clay, or an artificial mixture of carbonate of lime and clay in similar proportions, and then reducing the product to fine powder between millstones. In this condition its weight should not fall short of 101 pounds and will seldom exceed 128 pounds to the bushel, poured in loosely and struck, without being shaken down or compacted. Between these limits additional weight may always be conferred in the burning, by augment- ing the intensity and duration of the heat; and both the tensile strength, and the time required to set, increase directly with the weight. For example, a Portland cement weighing 100 pounds to the United States bushel, that will set in half an hour, and sustain when seven days old a tensile strain of 200 pounds on a sectional area of one square inch, would have its time for setting increased to four or five hours, and its tensile strength to about 400 pounds, if burnt to weigh 124 pounds to the bushel. An increase in weight of 24 pounds to the busbel nearly doubles the ultimate tensile strength of Portland cement. When the matrix of beton agglomere is Portland cement alone, it is customary to prolong the process of trituration, in order to retard the set ; or, if more convenient, the mixture may be passed through the mill twice or even three times, with an interval of an hour or more between each mixing. This course is specially desirable when the cement weighs less than 100 pounds to the bushel, and is correspondingly quick- setting. TESTS FOE PORTLAND CEMENT. 11. English test.— English engineers generally require that the cement shall be ground so fine that at least 90 per cent, of it shall pass a ^o. 30 wire sieve, of 3G wires to the lineal inch, and shall weigh not less than 106 pounds to the struck bushel, when loosely poured into the measure. When made into a stiff paste without sand, it should be capable of sustaining without rupture, a tensile strain of 400 pounds on a sectional area 1^ inch square, or 2^ square inches, (equal to 178 pounds to the sectional square inch,) seven days after being moulded, the sample being immersed six of these days in fresh water. 12 BfiTON AGGLOMEeE. In some cases a weight per bushel of 110 pounds, and a ten- sile strength, at tlie age named, of 222 pounds per square inch, are required. 12. French test. — The tests applied hy French engineers are not difficult to fulfil, and are considerably below what a good Portland cement will sustain. The cement must be ground to a fine powder, so that not more than 10 per cent, will fail to pass a Xo. 35 wire cloth of 17 meshes to the lineal inch, and weigh when loosely poured into the measure not less than 1,230 grammes to the litre, which is equal to about 97 pounds to the United States bushel. The test of streugth is applied to a stiff mortar composed of what is equivalent to about 3J quarts of dry sand and lOJ quarts of cement powder, which, being mixed with tresh water and formed in a suitable mould, is at once immersed in water. At the end of five days it should sustain a tensile strain of 1G7 pounds on a section of 2.18 square inches, equal to 07 J pounds to the sectioual area of 1 square inch; and at the end of 45 days, immersed in sea-water, the tensile strength to the square inch must not fall short of 112 pounds. The cement is required to be slow-setting. Should a stiff paste without saud sustain, in less than two hours, the point of a square needle, measuring 1^ millimetres (about -pf f „ of an inch) on the side, loaded to 3J(A_ pounds, it is rejected. It is, however, required to support, without the least depression, the the same loaded needle at the expiration of ten hours. Samples from a cargo of Boulogne Portland cement, received in New York in July, 1870, weighed 97 pounds to the United States bushel when poured loosely into the measure, and 127 pounds when well compacted by shaking. 13. G-erman cement— The standard Portland cements of Germany generally range in weight, when poured loosely into the measure, from 90 to 100 pounds to the struck United States bushel. A sample from a lot of Stettin cement weighed 89 pounds to the bushel, loose, and 11G| pounds when well shaken. Another sample weighed 95 and 122 pounds respectively, simi- larly treated. 11. Composition of Portland cement, (from analyses:) Boulogne Portland cement, (natural.) j London Portland cement, (artificial.) -Lime Co. 13 Mafrmvsiii BETON agglomErE. 13 MATERIALS NOT SUITABLE FOR BETON AGGLOMERE. 15. As a rule, all hydraulic cements i)roclucecl at a low lieat, whether derived from argillaceous or argillo-magnesian lime- stones, are light in weight and quick-setting, and never attain, when made into mortar or beton, more than 30 to 33 per cent, of the strength and hardness of Portland cement placed in similar circumstances. They are also greatly inferior to good hydraulic lime. This is true of all cements made at a low heat, including even those derived from limestones, that might, with proper burning, have yielded Portland cement. The celebrated Eoman cement, the twice-kilned artificial cements, the quick- setting French cement, like that of Vassy, and all the hydraulic cements manufactured at the i)resent day in the United States, belong to this category. They are incapable, under any known method or degree of manipulation, of producing a matrix suita- ble for beton agglomere of good quality. These kinds of cement generally weigh, among the different varieties, from 65 to 80 i)ounds to the United States bushel, poured in loosely, and from 80 to 93 pounds if compacted by shaking and jarring the measure. The weight of Eosendale cement per bushel is 67 pounds when loose, and 92 pounds when well shaken down. 16. Analyses of light, quick-setting cements: Eosendale cement stone, ( New Tork.) Carbonate of lime 46. 00 Silica, clay, and insoluble silicates 27.70 Carbonate of magnesia 17.76 Alumina 2.34 Peroxide of iron 1. 26 Sulphuric acid 26 Cblorides of potassium and sodiiim. . . 4. 02 Hygrometric water 22 Loss 44 100. 00 Cumberland cemerit stone, ( Maryland.) Carbonate of lime 41.80 Silica, clay, and insoluble silicates 24. 74 Magnesia 4. 10 Alumina 16. 74 Peroxide of iron 6. 30 Soda 4. 64 Potash 1. 54 Suljihuric acid 2. 22 Hygrometric water 60 Gain, (2.68) 102. 68 Yassy cement stone, (France.) Carbonate of lime 63.8 Silica 14. 0 Alumina 5. 7 Carbonate of iron 11.6 Carbonate of magnesia 1. 5 Water and loss 3. 4 100. 00 Balcony Falls stone, ( Virginia.) Lime 17. 38 Silica 34. 22 Alumina 7. 80 Magnesia 9. 51 Carbonic acid 30. 40 Water and loss 69 100. 00 For analyses of several other cements of this class, see Gillmorc on Limes, &c,, page 125. 14 BfiTON AGGLOMfiEfi. THE INDUEATION OF MORTARS. 17. The setting or hardening- of mortars, except so far as it is due in some degree to the absorption of carbonic acid from the atmosphere, is a si)ecies of crystallization induced when water is added to the compounds found in the kiln by the agency of heat. Mortars of common lime harden by the absorption of carbonic acid from the atmosphere, by which a sub-carbonate of lime is formed. The lime never takes up its full equivalent of carbonic acid. If the limestone be silicious, the calcination produces silicate of lime. Si O3 3 Ca O, which becomes hydrated by combining with six equivalents of water, producing hydrosilicate of lime, Si O3 3Ca 0+6 HO. If the carbonate of lime be in excess in the stone, the burnt product will contain both silicate of lime, and quicklime, or protoxide of calcium. It will slake to powder by the suffusion of water, if the quick- lime be present in sufficient quantity, producing a species of hy- draulic lime, of which the hydraulic energy will depend on the amount of silicate produced during the calcination. If the limestone be argillaceous— that is, if it contain alumina as well as silica — a calcination at a low heat produces both sili- cate and aluminate of lime. The latter becomes hydrated by taking six equivalents of water, and is then represented by the formula Al O3 3 Ca 0+6 HO. If the silica and alumina be present in the form of homoge- neous clay, and in suitable quantity, say less than 20 per cent., the burnt stone will slake, yielding hydraulic lime resembling more or less those of Seilley and Theil, France. If more than 20 per cent, of clay be present, the lime will be so little in excess that the burnt stone may not slake, but must be reduced to powder by grinding. The result, if burnt at a low heat, is light, quick-setting cement, like the Eoman. If this stone be burnt at a high heat, the reactions in the kiln are somewhat more complicated, particularly when the point of incipient vitrification is reached, a variable point, dependent in a great measure on the fluxes present in the stone. The com- pounds formed under these conditions, however, require but BfiTON AGGLOMfiRfi. 15 three equivalents of water for their hydration, their formulas being AI2 O3 3 Oa 0+3 HO, Si O3 3 Ca 0+3 HO. Herein lies the probable cause, in a great measure, of the supe- rior strength and hardness attained by Portland cement over the quick-setting varieties burnt at a low heat, in which the compounds take six equivalents of water to form hydrates. Magnesia plays an important part in the setting of mortars derived from the argillo-magnesian limestones, such as those which furnish the Eosendale cements. The magnesia, like the lime, appears in the form of the car- bonate, (Mg O 0 O2.) During the calcination the carbonic acid is driven off, leaving protoxide of magnesia, (Mg O,) which comports itself like lime, in the presence of silica and alumina, by forming silicate of magnesia and aluminate of magnesia. Si O3 3Mg O, AI2 O3 3 Mg O. These compounds become hydrated in the presence of water, and are pronounced by both Vicat and Chatoney to furnish gangs which resist the^issolving action of sea water better than the silicate and aluminate of lime. This statement is doubtless correct, for we know that all of those compounds, whether in air or water, absorbs carbonic acid, and pass to the condition of sub-carbonates ; and that the carbonite of lime is more solu- ble in water holding carbonic acid and certain organic acids of the soil, in solution, than the carbonate of magnesia. Hence cements derived from argillo-magnesian limestones are durable for constructions in the sea, unless other ingredi- ents introduce adverse conditions. THE FABRICATION OF BETONS AGGLOMERIES. 18. Experience has repeatedly demonstrated, and they have become well recognized facts, that in order to obtain uniformly good beton or artificial stone, with sand, and either hydraulic lime or Portland cement, or both, it is necessary— First. To regulate, in a systematic manner, the amount of water employed in the manufacture thereof. Second. To obtain, with a minimum quantity of water, the cementing material or matrix in a state of plastic or viscous paste. 16 BETON AGGLOMfiRfi. Third. To cause each grain of sand or gravel to be entirely lubricated with a thin film or coating of this paste ; and Fourth. To bring each and every grain into close and inti- mate contact with those which surround it. It is also equally true, that the best results possible to be produced from any given materials will be attained when the above-named conditions are enforced. TREATMENT OF THE MATRIX. 19. It is impossible to produce a cementing material, of suit- able quality for beton agglom6r6, by the ordinary methods and machinery used for making mortars 5 for if we take the powder of hydraulic lime or Portland cement, and add the quantity of water necessary to convert it into a paste by the usual treat- ment, it will usually contain so much moisture, even after being incorporated with the sand, that it cannot be compacted by ramming, but will yield under the repeated blows of the ram- mer like jelly. If the quantity of water be reduced to that point which would render the mixture, with the usual treatment, sus- ceptible of being thoroughly compacted by rammers, much of the cementing substance will remain more or less inert, and will perform but indifiEerently well the functions of a matrix. To prepare the matrix, there is taken of the hydraulic lime or cement powder, say one hundred parts, by measure, and of water from thirty to thirty-five or forty parts, which should be the smallest amount that will accomplish the object in view. These are introduced together into a suitable mill, acting upon the materials by both compression and friction, and are sub- jected to a thorough and prolonged trituration, until the result is a plastic, viscous, and sticky paste, of a peculiar character, in both its physical appearance and the manner in which it com- ports itself under the subsequent treatment with rammers. There would appear to be no mystery in this part of the process, yet the excellence of the beton agglomere is greatly dependent on its proper execution. If too much water be used, the mixture cannot be suitably rammed; if too little, it will be deficient in strength. TREATMENT OF THE SAND. 20. The sand should be deprived of surplus moisture, although it is not necessary that it be absolutely dry. A uniform state of moisture or dryness should be aimed at, in order that the BfiTON AGGLOMfiRfi. 17 proper quantity of water may be added witli certainty. With regard to the selection of the sand, nothing need be added to what has been said in paragraph 4. TEITURATION. 21. The matrix in paste, and the sand, having been mixed to- gether in tlie desired proportions, (given hereafter,) are then introduced into a powerful mill, and subjected to a thorough and energetic trituration until, without the addition of more water, the paste presents the desired degree of homogeneity and plas- ticity. When, for any special purpose, it is desired to introduce into the mixture a quantity of Portland cement, in order to increase the hardness or the rapidity of induration, it had better be added during the process of trituration, mixed with the requi- site increment of water, so that after proper mixing the whole material will present the appearance of a short paste, or pasty powder, which is quite characteristic of this process of manip- ulation. In ordinary practice, when sand and hydraulic lime only are employed, it will be found to answer very well to mix the two together dry, with shovels, and then spread them out on the tloor and sprinkle them with the requisite minimum amount of water. The dampened mixture is then shovelled into the mill and triturated, as already described. When a portion of Portland cement is used, it may also be incorporated with the other ingredients before the water is added, or introduced into the mixture in the mill, as may be X)referred. When Portland alone is used for the matrix, the process is the same as when lime alone is used, except that the trituration should be more prolonged, especially if the cement be rather light and quick-setting. 22. The market value of Portland cement per ton is gener- ally not far from double that of good hydraulic lime. Having both equally at command, the following proportions are em- ployed for divers purposes, according to circumstances and the quality of the materials : Sand, by volume 6 5 4 5 5 4 4 5 5 5 Hydraulic lime in powder, by volume 1 1 1 1 1 1 1 1 1 1 Portland cement in powder, by volume 0 0 0 i 2 i i 1 li H 2 18 BfiTON AGGLOMfiEfi. It will rarely occur tliat the proportions given in the two columns on the right of the above table need be used. They are suitable for ornamented blocks, requiring removal and handling a day or two after being made. 23. It may sometimes happen that too mucli water has been introduced in the preparation of the paste. A proper correct- ive, in such case, is the introduction into the mill of a suitable quantity of each of the ingredients, mixed together dry in the required proportions. By employing none but white sand and the lighter-colored varieties of lime and cement, a stone closely imitating white marble may be made, while, by the introduction of coloring matter into the paste, such as ochres, oxides, carbonates, &c., or fragments of natural stones, any variations in shade or tex- ture may be produced, from the most delicate buff and drab, to the darkest grays and browns. In some cases it may be found more convenient to measure the ingredients directly into the mill, alternatiug with the different materials, in regular order, using for the purpose measures of various sizes, corresx^onding with the required proportions. When it is specially desirable to obtain stone of the maxi- mum degree of strength and hardness, the paste may be returned a second or even a third time to tlie mill, but in all cases the mass must be brought to the characteristic state of incoherent i)asty powder, or short paste. AGGLOMEEATTON. 24. The materials, after being mixed to a state of pasty pow- der, have to be agglomerated in moulds, in order to become beton or artificial stone. In other words, the grains of sand and gravel, each coated all over with a thin film of the matrix — entirely exhausting the matrix thereby — have to be brought into close and intimate contact with each other. This is accomplished by ramming the paste in thin, successive layers, in a mould of the form and dimensions required for the stone, and made so as to be capable of sustaining heavy pressure from within, and of being taken apart at pleasure. Into this mould, supposing it to be for a detached building block, and not for monolithic masonry, a quantity of the stone paste is thrown with a shovel, and spread out in a layer from 1^ to 2 inches thick. It is then thoroughly compacted by the BfiTON AGGLOMfiRfi. 19 repeated and systematic blows of an iron-shod rammer, nntil the stratum of material is reduced to about one-tbird its origi- nal thickness. When this is done, its surface is scratched or roughened up with an iron rake, in order to secure a perfect bond with the succeeding stratum, and more of the material is added and i)acked in the same manner. This process is con- tinued until the mould is full. The upper surface is then struck with a straight edge, and smoothed off with a trowel, after which the full mould may at once be turned over on a bed of sand, and the bottom, side, and end pieces removed. The block is then finished. If small, such as one man can handle, it may be safely removed after one day. Larger pieces, like sills, lintels, steps, platforms, &c., should be allowed a longer time to harden, in consequence of their greater weight. In case of monolithic masonry, the moulds usually consist of a series of planks i^laced one above the other horizontally, and supported against exterior uprights, so arranged as to give the required form to the work under construction. These planks are raised up as the w^all progresses, so that each day's work shall unite intimately with that of the previous da}', producing a smooth and even surface, without joints, ridges, or marks of any kind. 25. A characteristic property of this stone paste, when i^rop- erly mixed, is that it does not assume a jelly-like motion when rammed. Its degree of moisture must be precisely such that the effect of each blow of the rammer shall be distinct, local, and i^erma- neut, without disturbing the contiguous material compacted by Ijrevious blows. If it be too moist, the mass will shake like wet clay, and if it be too dry, it will break up around the ram- mer like sand. In either case the materials cannot be coni- l^acted and agglomerated in that manner and to that degree which is characteristic of, and peculiar to, beton agglomere. 26. In monolithic buildings of this beton, it is customary to construct all the flues, pipes, and other oi)enings for heating and ventilating, and for conveying water, gas, and smoke, in the thickness of the wall, by using movable cores of the required size and form, around which the material is i^acked. As the work progresses the cores are moved up. Ornamental work of simx)le design may be placed upon the exterior of the building, by attaching the moulds to the plank- ing which gives form to the wall. 20 BfiTON AGGLOMfiEfi. More elaborate designs, especially if they are of bold relief, like cornices, and hoods for windows and doors, had better be moulded in detached pieces some days in advance, and hoisted into position when required. 27. All kinds of masonry in thin walls, whether of brick, stone, common concrete, or beton agglomere, are liable to crack from unequal settlement, or from the expansion and contraction due to ordinary changes of temperature. In houses, such cracks are more to be apprehended at the reentering angles of the exterior walls, and at the junctions of the exterior and par- tition walls, than elsewhere. In concrete or beton masonry, such cracks may be prevented in a great measure, without inconvenience and at a nominal cost, by imbedding and incor- l)orating in the work as it progresses, at the angles and junc- tions referred to, pieces of old scrap-iron of irregular shape, such as bolts, rings, hooks, clamps, wire, &c. 28. Any masonry of fair quality, constructed in large masses with special reference to inertia, whether to resist the thrusts of earthen embankments, the statical pressure of water, the force of the current in running streams, or for any other pur- pose, possesses a degree of ultimate strength much greater than the usual factor of safety would require, and largely in excess of any strain that it would ever have to sustain. This excess of strength, or rather the material which confers it, may be readily saved in works built of beton agglomere, by leaving large hollows or voids in the heart of the wall, and filling them up with sand or heavy earth. Even if the voids remain unfilled, a hollow wall is more stable than a solid one containing the same quantity of material, for the reason that the moments of the forces which confer sta- bility are greater in the former than in the latter. MACHINEEY AND IMPLEMENTS. 29. All the machinery and appliances for making beton agglomere are simi)le in character, and not liable to get out of order with use. They comprise, besides the necessary shovels and measures for handling and apportioning the ingredients, 1. A machine for mixing the materials together. 2. The means for conveying it, after mixing, to the place where it is to be used. 3. Kammers for compacting the materials in the moulds. 4. Moulds of the required form. BfiTON AGGLOMErE. 21 30. Mixing machine. — The first requiste is a machine that shall thoroughly and uniformly mix the ingredients together. It has been found in practice that a combined pressing and rolling motion secures the best results. 31. The ordinary upright pug mill, modified in some of its de- tails, answers this purpose. It is cylindrical in form, made of boiler iron, and has a vertical revolving shaft in the axis, armed with horizontal radial arms or knives, arranged spirally around it. Other horizontal arms are attached to the inner surface of the cylinder, projecting out between the revolving arms, so as to subdivide the materials and aid the mixing. Three or four of the revolving arms, near the lower end of the shaft, are made warped, or helicoidal, like the blades of a screw-propeller, to press down as well as stir the mixture ; and below these, revolv- ing near the floor or bottom of the mill, are three cycloidal arms, to force out the mixed materials at the side openings around the bottom, whence it is at once conveyed away for use. These openings are provided with cylindrical sliding gates, by means of which their area may be diminished, and the rapidity with which the material is ex])ellecl, retarded, whenever, for special X)urposes, a prolonged trituration is desirable. As the beton, ready for use, is ejected at the bottom, the cylinder is kept full by new material introduced at the top, a measure of cement, lime and sand, incorporated dry, alternating with a ijroportionate measure of water. In operating with mills of large capacity, there is an advantage in conveying up the materials with an elevator discharging its buckets into an i^jclined shoot leading into the mouth of the cylinder. The requisite amount of ATater may be supplied by constant flow from a pipe. This amount must, however, be ascertained by trial, and will vary with the character and the proportions of the lime and cement used. In conducting extensive operations the mill should be worked by steam-power. 32. The Greyveldinger mortar mill is believed to be fully equal, if not superior, to the pug mill. It is an Archimedean screw, revolving in a cylindrical trough. The dry ingredients of the b^ton, having first been roughly mixed with shovels, are intro- duced at one end oi the screw with the requisite amount of water, and after an interval of fifteen or twenty seconds issue from the other end in a condition of thoroughly mixed beton. When used for making common mortar, the screw may occupy 22 BfiTON AGGLOMl^Rfi. a liorizontal position, but' for betoii agglomere it is better to have it set at an angle of about twenty-five degrees with the horizon, in order tliat the benefits of the trituration and pressure, developed in forcing the material up the inclined cylinder, may be secured. A convenient way of accomplishing this object is to mount the machine on wheels like a cart, as shown in Plate III. A mortar mill of this kind, set horizontally, of suitable size to be driven hy a half-horse-power engine, can make 'SS-f-^ cubic yards of mortar in ten hours, the force required to tend it being 8 common laborers, I foreman, and 1 engineer. Estimating common labor at $1 70 per day, and the wages of engineer and foreman at $2 50 and $2, respectively, the cost of making mortar by this mill, including the coal, would be 48 cents per cubic yard. The more thorough and prolonged tritu- ration required for beton agglomer<5, and the additional power expended in forcing the mixture up the inclined cylinder, would augment the cost about 10 per cent. 33. The malaxator. — Many advantages are claimed for a mill designed by M. Coignet, recently introduced in France, and em- l>loyed in mixing beton agglomere for the works in and about Paris. It is called a malaxator, and consists of twin screws, Inn ing their helices interlocked, and turning and exerting their force in the same direction. This machine may be described as follows : (See Plate 11.) A is the frame of the machine, having at the upper end the cross-pieces B, upon which are mounted the gearings, and at the lower part the cross-piece c c', upon w^hich are fixed the rests or steps for the lower ])art of the helices to Tun in. D are the cores of the helices, upon which are fastened either continuous or interrupted blades S S S, forming the thread of the helix. Continuous blades are more generally used. K are wagon-wheels, mounted on an axle, which enable the machine to be transported thereon, and wiiich, when the ma- chine is in use, serve to maintain the malaxator at its proper inclination, (about twenty-five degrees.) The brace J is used to steady the malaxator. M N m IST', gearings of any kind for giving motion to the helices, either by steam, horse-power, or hand-power; q, coni- cal sleeves or stoppers, adjustable upon the shafts D, for regu- lating the exodus of the artificial stone paste, and by retarding the same, increasing the pressure and malaxation of the paste in the part Q' of the machine. BfiTON AGGLOMfiRE. 23 Q, body of the malaxator, corresponding in shape and size to the helices. P, receiving chamber, where the materials enter the malaxator. T, sand hopper, with its adjnstable register or gate t, and, wlien required, a sifting apparatus ; q', sliding gate, to allow of the drainage of the machine. S' S', feeding screws, working in the lower part of the two hoppers WW, the oue for liuie, the other for sand, or any other material or substance to be introduced into the ar- tificial stone paste, and feeding the same to the chamber P ; r r' r" r'", pulleys, for chains or belts O O T-J rH r-i O »H s s a ^ — S 6 S fi 9 S ?. a g g g g ' s a o o r- r3 ra rS c 0 a 0 a s a cs ci cS ci cS cS ,-1 T)- t» 0 R a n a n o (B o a a> » (0 OJ © OJ a a a a aaaaaoaaa . coooocooc — g rH ^ ^ «^aapaaaaaao a a a s g -^s ^ -5 ~ ^ ^ ^ o i « a a a a a a a P^P^P^P^P^P^P^P^!^ THCirD-^ir^tot^-cocriO ,0 ci ^ a c n /l^ H ^ 28 BfiTON AGGLOMfiEfi. The results given in Tables II and III are tlie averages obtained hj testing several samples, generally four, of eacb particular mixture. 40. In preparing the following table, some of the samples were mixed with a very small quantity of water, and rammed into the mould, as described for making beton agglomere, while others were made plastic like over-stiff mason's mortar, and pressed tirmly into the mould with a trowel, care being taken in each case to render the mixture as compact as possible. The results indicate, with great prominence, the advantages of using but a small amount of water, and of thorough ramming. The proportions of dry ingredients by weight only are given, the corresponding proportion by volume having been recorded in Table II and III. Table IV". — {From General Gillmor^s experimenis.) No. Proportions of dry ingredients, by weight. How mixed and treated. Tensile strength per sq. inch ; blocks 7 days old ; in water 6 days. Pounds. 1 Portland cement, 1 ; sand, i Like b6ton agglom6r6 . . . 377 2 Portland cement, 1 ; sand, i Like common mortar. . . 289 3 Portland cement, 1 ; sand, \ Like beton agglomere . , 320 4 Portland cement, 1 ; sand, | Like common mortar 222 5 Portland cement, 1 ; sand, 1 Like beton agglomer6 . . 244 6 Portland cement, 1 ; sand, 1 Like common mortar 197 7 Like b6ton agglomere. . . 179 8 Portland cement, 1 ; sand, IJ Like common moi'tar . . . 129 9 Portland cement, 1 ; sand, 2 Like beton agglomer6 . . 138 10 Portland cement, 1 ; sand, 2 Like common mortar 109 11 Portland cement, 1 ; sand, C Like beton agglom6re . . 66 12 Portland cement, 1 ; sand, G Like common mortar 35 13 Portland cement, 1 ; sand, 8 Lilie beton agglom6re . . 39 14 Portland cement, 1 ; sand, 8 Like coTnmon mortar. . . . 24 15 Rosendale cement, 1 ; Portland cement, J Like b6ton agglom6r6 . . 96 16 Eosendale cement, 1 ; Portland cement, J 40 17 Rosendale cement, 1 ; Portland cement, i Like b6t()n agglomer6 . . 129 18 Rosendale cement, 1 ; Portland cement, i Like common mortar 44 41. Tensile strength of cements made by the jS'ewark and Rosendale Cement Company, mixed with little water and rammed into moulds like beton agglomere. B£T0N AGGLOMfiEfi. 29 Table V. — {From General Gillmoi-e's experiments.) TROPORTIONS FOR THE DRY INGREDIENTS. •1 Tensile strength per scj^uare incli ; blocks 7 days No. By wciglit. By volume, loosely measured. By volume, well- sliaken. old; in water 6 days. Pounds 1 Kosendale cement, pure. 72 2 Kosendale cement, 1 ; sand, 1. 51 3 Eoseudale cement, Kosendale cement, 1 ; Kosendale cement. 40 1 ; sand, 2. sand, 1. 2. 1 ; sand, 1. 4. 4 Kosendale cement, Kosendale cement, 1 ; Kosendale cement. 33 1 ; sand, 3. sand, 1. 8. 1 ; sand, 2. 5 Kosendale cement. Kosendale cement, 1 ; Kosendale cement. 22 1 ; sand, 4. sand, 2. 4. 1 ; sand, 2. 8. 6 Kosendale cement, Kosendale cement, 1 ; Kosendale cement. (*) 1 ; sand, 6. sand, 3. 6. 1 ; sand, 4. * Less than 10 pounds. The mixtures used for Table V were made witli little water, and were in all respects manipulated and treated like beton agglomere, as far as this could be done by hand. The point arrived at was to use as much water as possible without ren- dering the compound so wet that it could not be thoroughly compacted by ram ruin gs. If water enough be used to make the mixtures plastic, like masons' mortar, the tensile strength is very greatly diminished, in proportion to the amount of water used. 42. The Eosendale cements vary greatly in quality from time to time, depending on the greater or less care used in selecting the stone from the several layers as they are taken out of the quarry. It is only when special pains are taken in its manufacture that an article can be produced capable of sustaining a tensile strain of 70 pounds to the square inch upon blocks seven days old, made plastic like mortar, but without sand. When made and compacted like beton agglomere the strength is about doubled. The average quality ranges considerably below this strength, sometimes as low indeed as 25 pounds to the square inch. All the several brands may reach both these limits in the course of a single season. A tensile strength of 65 pounds to the square inch in seven days is seldom exceeded 30 BfiTON AGGLOMfiRfi. by any of them, while, exceptionally, some are adulterated to a strength of only 18 pounds. Samples of Eosendale cement brought to the IiTcav York mar- ket during the same week in the month of August, 1870, by five different companies were tested with the results recorded below in Table YI. 43. Tensile strength of several Eosendale cements, without sand, mixed to a stiff paste. Table VI. — (From General Gillmore^s experivients.) Tensile strenth jjer square inch ; blocks seven clays old ; in Avater six days. Number one 64 pounds. 65 pounds. 39 pounds. 39 pounds. 28 pounds. Number two Number three Number four Number five 41. Tables II, III, lY, Y, and YI afford the means of com- paring the tensile strength of Portland cement, in various com- binations and under various conditions, with Eosendale cement similarly treated, the mixtures being in every case kept one day in the air and six days in water, and broken when seven days old. The diagram, Plate I, shows the progressive increase of strength with age of Portland cement mortars, compiled from trustworthy authority. It will be seen by inspection that the cements of the diagram were inferior, when seven days old, to those of Tables II and III, while they range between the strongest and weakest of those of Table I. 45. The mortars which furnished the following table (YII) were mixed in the summer of 1869, and were left in one of the casemates of Fort Tompkins, covered with sand, until fifteen months old, when they were broken. They were kept in a damp condition, but were never immersed in or wet with water. They therefore attained their age under circumstances not specially favorable to induration, and the results are not considered of great value. BfiTON AGGLOMfiRfi. 31 The Portland cement weighed 98 pounds, the American cements 07 to G8 pounds, and the sand 114 pounds to the bushel, loosely measured. The lime was the common or fat lime from Glen's Falls, New York, and was slaked to a paste. The several mixtures were made up soft, like masons' mortar, and therefore could not be compacted by ramming, like beton agglomere. Table VII. — (From General Gilhnore's ex])erinients.) No. Proportions of ingredients, by volume. Tensile strength per square inch ; blocks 15 months old. Pounds. 1 Boulogne Portland cement, without sand 496 2 Delafield & Baxter's Rosendale cement, without sand . . . 154 3 Bondurant & Ford's Louisville cement, without sand 151 4 Coplay (Pennsylvania) cement, without sand 139 5 Boulogne Portland cement, 1 ; sand, 1 320 6 Boulogne Portland cement, 1 ; sand, 3 160 7 Delafield & Baxter's Kosendale cement, 1 ; sand, 1 132 8 Delafield & Baxter's Eosendalo cement, 1 ; sand, 3 63 9 Bondurant & Ford's Louisville cement, 1 ; sand, 1 123 10 Bondurant & Ford's Louisville cement, 1 ; sand, 3 51 11 Coplay (Pennsylvania) cement, 1; sand, 1 81 12 Portland cement paste, 1 ; fat lime paste, 1 : of this mixture, 1 80 volume ; of sand, 3 volumes. 13 Delafiefd & Baxter's cement piiste, 1 ; fat lime paste, 1 : of this 39 mixture* 1 volume; of sand, 3 volumes. 14 Bondurant & Ford's cement paste, 1 ; fat lime paste, 1 : of this 44 mixture, 1 volume ; of sand, 3 volumes. 15 Coplay cement paste, 1 ; fat lime paste, 1 : of this mixture, 1 vol- 31 ume ; of sand, 3 volumes. 4G. Some trials of artificial Portland cement, manufactured at Stettin, Germany, weighing 89 pounds to the United States bushel, loosely measured, and 122 x)ounds when well compacted by shaking, gave the results recorded in Table YIII. 32 BfiTON AGGLOMfiRl?. a; ^ >s g ^ 2 '3 Pi ,2 o o S 1-1 rl i-H fx CO CM i-^ O lO . t- ira (T« _ ira r-^ .o ^ ^ ^ g ^ ,5 ^ ^ ;§ ft P< ft ft ■TJ r- m ^ t~ o O HI 2 a a a rl n i^i to O) 3 3 3 2 3 3 n= rO ^ ^ ^ ft o a; o a:) © , ft ft ft ft ft ft '2 Irt CO tH c*^ 1^* to '3ra'!3''3'Si-Zl'3'5'rt'^ 01 O) O! <» OS 03 02 C4 cS CS C3 c a a q p OJ a; 0^ O) CD a a g a a a fi fi s fl a © 03 a; o a a s a a poogggacsaflfl rH (M CO TJi 10 to ft ft ft ft ft CO 00 o OJ C. -"J. 10 CO _ ^ a a a a fl c a. CO 3 rs 3 -5 s'-S a a g aaggcBraSiB S § a § a ^ a ^ a; a; 03 0 o QJ gaPdaoaaaria g II a Ph (i< rt(MmTtiLTC0t-00C5Oi-(ressure, 9 inches x 4| inches, equal to an area of 38^ inches. Tablic X. — {From Mr. Grant's experiments.) Proportions. Neat cement 1 volume cement, 1 volume sand . 1 volume cement, 2 volumes sand 1 volume cement, 3 volumes sand 1 volume cement, 4 volumes sand 1 volume cement, 5 volumes sand Neat cement 1 volume cement, 1 volume sand . 1 volume cement, 2 volumes sand. 1 volume cement, 3 volumes sand. 1 volume cement, 4 volumes sand 1 volume cement, 5 volumes sand Neat cement 1 volume cement, 1 volume sand.. 1 volume cement, 2 volumes sand. 1 volume cement, 3 volumes sand. 1 volume cement, 4 volumes sand. 1 volume cement, 5 volumes sand. Age of bricks. months months months months mouths months months months months months months months months months months months months months Total crush- ing weight. Tons. 65 43 34 24 23 16 92 .59 47 37 31 26 102 78 62 41 33 29 Crushing weight per square inch. Pounds. 3, 806. 5 2, 518. 3 1, 991. 2 1, 405. 6 1, 347. 0 938.0 5, 388. 0 3, 455. 3 2, 752. 6 2, 1G7. 0 1, 815. 5 1, 522. 7 5, 973. 6 4, 568. 0 3, 631. 0 2, 401. 2 2, 225. 5 1, 698. 4 35 The foregoing table (Table X) is defective in tliat it does not give the weight of the cement emi)loyed in the trials. The tensile strength of Portland cements, as already stated, may be doubled by a judicious increase of the intensity of the heat in burning, and the presumption is that their capacity to resist compression may be augmented, possibly to as great a degree, by the same means. 50, The strength of Boulogne Portland, and American Eosen- dale cements to resist compression is shown in the following table, from tests applied to blocks 3 J inches wide, 5^ inches long, and 3 inches thick, the area under pressure being 19| square inches. The Portland cement weighed 127 pounds, and the Kosendale 02 pounds to the United States bushel, both being well com- pacted by shaking. When tested, the blocks were seven days old, having been six days in water. Some of them were made with little water and thoroughly rammed^ like beton agglom^re ; others were treated like over-stiff masons' mortar, firmly pressed into the moulds with a trowel. The Kosendale cement was manufactured by Messrs. Delafield & Baxter, at High Falls, Ulster County, New York. 36 B15T0N AGGI.OM15RI5. ^ u I ^ fat ^ 5J i-™ O CO Oi ^ iO O CO lO o Ti? in lO CO lO o o o o o +J +3 -f- a e g 3 Q o P o o C S S hf> fcj) jTn r5 o o o 6 c o o lO ^ CO CO bJ3 fci) S) 5) fci' Eii S) "t SL 3 3 ,-H CI O lO ^ 00 T-l O* cf s US p P p % iZJ O P ? fee St & o lO o c< od to o S p 5 o £ 5 5 u -1^ -t-i o OD CO «J O) OJ •r; to CP to m M P< p p o P< p o CO O 4J CO o "bt 3 '3) ci g cs « a g -2 a -2 o © o 1^5 a a a> fi u pop M p S a 'm o a u u u ^ u o ci -D CS CO goPOpoSoCooooOPS^ Wi a 6fl O c P ^ P Q o " P * O " P P flsaartSgSgSgs a -Tij a Tr a "bc « l*g gaga >i) o P o p O © ^ ^ ^ ^ 3 3 3 3 3 3 3 3 © ffl OJ O P ^ ^ ^ rii ^ ;jiH5i-ii-it-ii-ii-ii-^i-^>-i GO CO »0 lO CO CO 'fO . ai 01 io to " ' ' CO r-; _ - <>j t^' ^ ^ © © 3 a o © a o © 2 c g © © a PI S g g 3 S © o © © © © p CO 00 , CD to ©©ag©©a" g«©©gs=i©j; ®ssg©©sa B 13^=3 a a^^ © (D^JVj© ^"•'^'^ OOOOt^POP 'cj a a a 45 ^ a a ^ ^ to a a 13 13 a g « a a 45 ^ PC3PPPCPOOO OP _ ^ _ - CO t^ D „ .. -3 t^ a a 13 " to <» cS o a CIS c3 a a c3 a a c; c3 a pj o) © a a a 3 a a +2- a a 3 3 © © a e! © © g a S 53 © © §33 © © © © o © * 3 '§ ^ CO O w P c o o Fc! M CL, fL, P4 CP o o © © "3 '5 =s 'S a a np a a"i3 a aJ343 a ©"ij+j © ©-fr^-fj © toi-, — tntoti^jM CPO©CPOp 'c3 "ci C3 Q CO cj cJ p CJ as S C "3 © © " *3 BfiTON AGGLOMfiRE. 37 Remarks on the trials wldch furnished the Taile XI. The blocks were crushed in a Jiydraulic press. They rested upon a thin layer of dry sand, in order to secure a better bearing. Sand was also spread evenly over the top surface of each block. Owing to inaccuracies in their form, and inequalities in tlio bearing surface, the tendency of the strain, when first applied, was to break the blocks transversely, long before the ultimate crushing weight was reached. In practice it is almost as difficult to guard against the error thus introduced as it is to compute its value. Tho circumstances attending the trials are therefore recorded as they occurred, as folloVs : No. 1. Cracked in two at 5,000 pounds, and crushed into several pieces at 14,000 pounds. No. 2. Crushed into several pieces at 2,000 pounds. No. 3. One transverse crack at 35,000 pounds, dividing the block into two pieces. Another crack at 55,000 pounds through one of the pieces. No more pressure could be produced by the machine. The block was removed in three solid pieces, but was not crushed. No. 4. Cracked at 38,000 pounds, and crushed into several pieces at 50,000 pounds. No. 5. Cracked at 3,000 pounds, and crushed into many pieces at 6,000 liounds. No. e. Cracked at 600 pounds, and crushed at 1,000 pounds. No. 7. Cracked at 32,000 pounds, and crushed at 54,000 pounds : one piece being about one-third the volume of the entire block. No. 8. Cracked at 10,000 pounds, and went into pieces at 20,000 pounds. No. 9. Crushed into many pieces at 2,200 pounds. No. 10. Cri^shed into many pieces at 1,200 pounds. No. 11. One crack at 8,000 pounds, another at 26,000 pounds, and crushed suddenly into five pieces at 28,000 pounds. No. 12. One crack at 12,000 pounds, another at 17,000 pounds, and crushed at 19,000 pounds. No. 13. One crack at 1,000 pounds, and cruslied at 3,000 pounds. No. 15. One crack at 7,000 pounds, another at 13,000 pounds, and crushed into many pieces at 18,000 pounds. No. 16. Cracked at 9,000 pounds, and crushed iuto many pieces at 14,000 pounds. No. 17. Crushed into small pieces at 1,000 pouuds. No. 19. Crushed into pieces at 10,000 pounds. No. 20. Crushed into pieces at 5,000 pounds. No. 21. Crushed into pieces at 9,000 pounds. No. 23. Crushed into pieces at 5,000 pounds. No. 24. Crushed into pieces at 2,000 pounds. 51. The following- table (XII) sliows the strength to resist com- pression, of beton or concrete composed of cement, sand, gravel, and pebbles. The gravel and pebbles Avere procured by screen- ing gravel from the sea-shore so as to remove everything smaller than one-eighth to one-sixth of an inch in diameter. It varied from the size of a pea to that of a pigeon's egg, and weighed 38 Bl^TON AGGLOMfiEfi. 126 pounds to the even United States bushel, loosely measured, and 135 pounds when well compacted by shaking. The cements and sand were of the same quality used in the former tables. The concrete blocks were formed by first incorporating the dry cement with the dry sand, and then adding sufficient water to convert the mixture into an over-stift' mortar. The mortar and gravel were then put into a cylindrical wooden bucket, with a close-fitting top, and mixed together by prolonged shaking, the bucket being revolved repeatedly during the operation, after which the concrete was rammed into moulds and left for twenty-four hours to harden. The blocks were never immersed in water, but were wet with a sponge every day, and crushed when ten days old. BfiTON AGGLOMfiE:fi. 39 Table XII. — (From General Gillmore's experiments.) No. SIZE OF BLOCKS. Proportions of the dry ingredi- ents, by volume. -IG In. I" Boulogne Portland cement . . 1 ■i Sand 3 ( Coarse gravel and pebbles - . 9 f Boulogne Portland cement. - 1 1 j I Sand - 4 • |5 7-lC (. Coarse gravel and pebbles. - 9 J C Boulogne Portland cement. . 1] \ •j Sand 4 15 7-10 [ Coarse gravel and pebbles. .10 f Boulogne Portland cement . I Sand [Coarse gravel and pebbles. C Boulogne Portland cement. . •I Sand [coar.se gravel aaul pebbles. . I Bouloguo Portlflud cemeut. 13 J 14J 3i s Sand . - [ Coarse gravel and pebbles. . C Boulogne Portland cement. . ■I Sand I, Coarse gravel and pebbles. . f ISTorton's Rosendale cement ■j Sand [ Coarse gravel and pebbles. C Norton's Rosendale cement J Sand [ Coarse gravel and pebbles. r Norton's Rosendale cement < Sand [ Coarse gravel and pebbles f Norton's Rosendale cement I Sand [Ciiaist^ !ira\T! aiul ])ebblts. 6 1-^5 7-1 15j i! ii 1 3 9 11 10 J a .a 3* 8, 600 9, 400 5, COO 7, 400 7, 000 8, 000 8, COO 6, 600 5, 833J 4, CCCf 4, 166§ 7, 000 4, 5G0 5, 040 4, 500 5, 7C0 8, 200 3, SCO 2, 000 Crushing -weight per square inch, in pounds. Blocks 10 days old. 452 494 294 388 367 420 452 347 306 245 218 367 239 265 237 303 293, (av'ge of 2 trials.) 114, (av'ge of 3 trials.) 3, 400 121, (av'ge of 4 trials.) 71, (high'stof2trials.) PEOPERTIES OF BfiTON AGGLOMERE. STRENGTH. 52. The most trustworthy report hitherto published upou the strength of beton agglomere to resist a crushing weight, is that of Mr. P. Michelot, ingenieur-iu-chef des Fonts et Chaussees, from experiments made at the Conservatoire Imperial des Arts et Metiers, France, in July, 18G4. The results of these trials are given in the following table. 40 BfiTON AGGLOMfiEfi. Tablk XIII. Date of fab- rication and age of samples. Feb., 1862, 30 montlis. 2* Jan., 1862, 31 months. 3* Jan., 18,62, 31 montlis. 4* Feb., 1863, 18 mouths. 5 Feb., 1862, 30 months. 6 Nov., 1862, 21 montlis. 7* Nov., 1862, 21 months. 8* Nov., 1862, 21 months. 9* May, 1863, 15 months. 10 May, 1863, 15 months. Composition of the samples in \'ohimcs of ingredients. {Kiver sand 4 llydraulii; liMHi of Argentienl 1 Cement, (Scliachw & Letellier) f Coarse river sand 5 } Hydranlic lime of Argentienl 1 [ Cement, (as above) J C River sand 5 <; Hydrauliclime of Argentienl 1 [ Cement, (as above) J [- Sand - 5 < Lime, (as above) 1 i. Cement, (as above) 1 ( Coarse sand 4 ■I Lime, (hydraulic,) of Thcil 1 [ Portland cement, (Boulogne) i C Mixed sand 4 s Hydraulic lime of Theil 1 I Boulogne Portland cement | f Coarse sand, washed 4 \ Hydranlic lime of Argentienl 1 [ Boulogne Portland cement f j" Coarse sand, washed 4 ; Hydi'imlic lime of Argentienl 1 [ Portland c'nit, (Schaoher & Letellier) J C Sand of Vesint't 4 < Hydrauliclime of Argentienl 1 [ Hydraulic c'mt, (Schacher(fe Letellier) i ( Sand of Ve.sinot 4 ■ lTydr;iulic lime ol' Argentienl 1 { Hydraulic c'nit, (Schachor & Letellier) i DIMENSIONS OV SAMl'LES, IN INCHES. li 2i Lhs. 130 >2i 3i 3} 139 4 142 :3i CUUSHING STUENGTH, IN rOUNDS. Total. inch. 3, 270 < 37, 744 4, 131 46, 641 4,546 24, 893 4, 172 i 34, 039 4, 040 72, 458 5, 650 r 46, 875 7, 176 \ 50, 110 7, 495 48, 019 5, 549 33, 467 5, 364 j 23, 462 ! 2, 682 23, 052 3,634 Explanation of Table XIII. ^. The samples marked thus (*) are pieces of blocks previously brokeu by a, tensile strain, and have the form of the letter T and the double numbers in the columns of length and br(>adth indicate the dimensions of the two rectangles com])osing the total ar;vi under compression. No. 1. Fissured. Tliis br'tou avms the same composition as that used in the vaults of the city barracks, Paris. Jfo. 2. The small lateral i)rism Avas first crushed. The other resisted tlie pressure, but was wrenched by having an nne«iual bearing. No. 3. One of the lower angles of the sample was imperfect, liaving been injured before the trial. Nos. 9 and 10 were of tlie same composition as the biSton used in tlio church of Vesinet. BETON AGGLOMERfi. 41 53. The blocks which furnished the following table were crushed in ^Tovember, 1870. They were cut from sills, steps, platforms, «&c., that had been exposed to the weather from the time they were made. During warm dry weather they were wet every day with a hose. Taulk XIV. — (From General Gillmoi-e'n exper'nnenlii.) Compositiou of samples in vol- umes of ingredients. f Pit sand 5 I Hydranlic lime of Seilloy 1 I, Boulogne Portland cement -.11 f Pit sand 5 I Hydraulic lime of SeiUoy 1 [Boulogne Portland cement.. li CFit sand 5 ■| Hydraulic lime of Seilley 1 [BoTilogne Portland cement.. li {Pit sand 5 Hydraulic lime of Seilley. . .1 Boulogne Portland cement.. IJ^ ^ Pit sand 5 ■i Hydraulic lime of Seilley 1 [Boulogne Portland cement. .1 I" Pit sand 5 s Hydraulic lime of Seilley 1 [ Boulogne Portland cement . . 1 fPit sand 5 } Hydraulic lime of Seilloy 1 [Boulogne Portland <'em('!it-.l fPit sand T) Hydraulic, lime of Seilloy. . . .1 Boulogne Portland conuiiit. .1 {Pit sand ^ Hydraulic lime of Seilloy 1 Boulogne Portland cement.. 1 {Pit sand 5 Hydraulic lime of Seilloy 1 Boulogne Portland cement.. ^ f Pit sand 5 ebbles, by measure 12 13 13 14 1 1 1 1 4 1 0 i f 1^0- 52 bEton agglom£ei5. 74 a. The following table (XVI) was not completed in time to take its proper place in this report, and is therefore inserted here. It gives the results of some of the trials that Avere made in determining the proportions recommended in the two fore- going paragraphs. Broken stone of various sizes, from that of a pea to that of a duck's egg, w^ould give better results than the gravel and pebbles that were employed. In Table XYI the blocks tested were two months old, and were exposed to the weather, through the months of December and January 1870-'71, upon the roof a building where the ther- mometer frequently reached as law as zero, Fahrenheit. Their dimensions were 3| by 5| by 3 inches, the area under compression bring 19^ square inches. It will be seen that the blocks containing 13 volu'mes of the gravel and pebbles gave a greater average strength than those containing 5 volumes, the other ingredients in both cases being the same. Table XVI. — {From General Gilmor^s experiments.) No. Proportions of dry ingredients by Tolnnie, loosely meas- ured. CRUSHING STRENGTH, IN POUNDS. Total. Per square inch. Boulogne Portland cement, 1 ; common lime powder, 0.4 ; sand, 5.6. Boulogne Portland cement, 1 ; common lime powder, 0.8; sand, 5.6. Boulogne Portland cement, 1 ; common lime powder, 0.4 ; sand, 7.5. Boulogne Portland cement, 1 ; common lime powder, 0.8; sand, 7.5. Boulogne Portland cement, 1 ; common lime powder, 0.4 ; sand, 5.6 ; gravel and pebbles, 5. Boulogne Portland cement, 1 ; common lime jjowder, 0.4 ; sand, 5.6; gravel and jjcbbles, 13. Boulogne I'ortlaiul cement, 1 ; common lime powder, 0.8 ; sand, 5.6; gravel and pebbles, 5. Boulogne Portland cement, 1 ; common lime powder, 0.8 ; sand, 5.6; gravel and pebbles, 13. 18, 000 16, 000 15, 500 19, 000 8, 000 10, 000 10, coo 11, 000 12, 500 13, 100 13, 000 16, 000 12, 500 12, 000 12, 5C0 14, 5C0 935 831 805 987 415i 519 551 571 649 C81 675 831 649 623 649 753 75. When the Archimedean screw-mixer is used, some diffi- culty will be experienced in incorporating the gravel and peb- bles with the same machine, from the liability of its getting jammed in between the edge of the screw and cylindrical case in which it revolves. The trouble will not arise from either the BfiTON AGGLOMfiRfi. 53 large or the small pebbles, but only from tlie medium sizes. The difficulty might be avoided by mixing with a pug mill suitably constructed, or by using two machines, one for incorporating the matrix with the sand, and the other a concrete mixer, for introducing the pebbles to the mixture thus obtained. For monolithic concrete work, in water, the lime should be omitted. GENERAL OBSERVATIONS. INCREASE OF STRENGTH OF BETON AGGLOMER^l AVITH AGE. 76. Betons and mortars, in which the matrix is Portland cement alone, acquire, during the first two years, fully nine- tenths of the strength and hardaess which they ultimately attain iu process of time. 77. Tensile strength. — At the age of one month the tensile strength of Portland cement, without sand, is equal to about two-thirds of what it attains during the first two years. When sand is added, the ratio of increase in tensile strength is greater than with the neat cement, sometimes reaching in two years, with the larger proportions of sand, as high as seven and eight times the strength acquired during the first month. With equal portions of cement and sand, the strength acquired in one month is about doubled at the end of two years. The curves of the diagram, Plate I, although of less value, in consequence of having been derived from various authorities, than they would have been if mt^de by one single experimenter, present a comprehensive view of this subject. The discrep- ancies Avhich present themselves under a close comparison, are due to the use of cements of various qualities mixed under va- rious conditions. 78. Crushing strength. — It is known that the strength of Portland ceuuuit mortars and betons, to resist compressiou, does not reach its maximum limit within a period of two or perhaps three years. During the first month the compressive strength of neat cement per square inch, upon blocks about the size of ordinary burnt bricks, laid flatwise, is from seven to eight times the tensile strength per square inch of the same mixture. At the age of six months this ratio becomes about 12 to 1, and at nine months nearly 14 to 1. When sand is added, the difference between the tensile and the crushing strength on the same unit of area is much greater than with cement alone, and increases with the amount of sand used. 54 BfiTON AGGLOMfiRfi. With a mixture of cement 1 and sand 2, the ratio of the crushing to the tensile strength will generally he found be- tween the limits of 14 to 1 and 19 to 1; with cement 1 and sand 4, it reaches as high as 25 to 1 and even 29 to 1; and with cement 1 and sand 5, as high as 35 to 1. These relations are maintained as a rule up to the age of nine months, beyond which period our information depends so much upon experi- ments made at different times and places, and by different per- sons, as to be in a measure impaired for practical use and application. As a rule, the crushing strength of betons, in which the matrix is Portland cement, at the age of three months, becomes nearly doubled at the age of nine months. 79. a. All possible mixtures of Portland or natural American cements, with or without sand, with much or little water, if arranged in the order of their strength at any time after they are five days old, will, as a rule, remain in that order through- out all subsequent induration. 80. American cements made from argillo-magnesian limestone at the following-named localities, when manufactured with care, do not differ greatly in quality, viz : Cumberland, Maryland ; Louisville, Kentucky; Utica, Illinois; Ooplay, Pennsylvania: Shepherdstown, Virginia; Bound Top, near Hancock, Mary- laud ; Akron, New York. They are, however, somewhat inferior to Eosendale cement of average quality. 81. The tensile strength of the best Portland cement, seven days old, is about six times as great as that of the best natural American cements, both being mixed without sand. About the same ratio exists between the medium grades, and also between the lower grades of these two classes of cements. This is true whether mixed with little water, like beton agglomere, or with much, like masons' mortar. 82. A mixture of Portland cement and sand, in proportions suitable for mortar, seven days old, made with much or little water, possesses from four to six times the tensile strength of a mixture of Eosendale cement and sand in the same propor- tions, similarly treated. 83. The tensile strength of both Portland and Eosendale cements, with or without sand, is less when made plastic, like stiff masons' mortar, than when made simply damp and inco- herent, like beton agglomere. With Portland cement the differ- BfiTON AGGLOMfiR]^. 55 eiice is from 20 per cent, to 30 per cent., and with Eosendale cements mncli greater. 84. The tensile strength of the best neat Eosendale cement, seven days old, is more than twice as great as that of the poorest, and when mixed with three times its weight of sand, is as strong as the poorest without sand. 85. Neat Eosendale cement mixed with neat Portland cement is very little better than the same weight of sand, until the amount exceeds six times that of the Portland cement. This result is from mixtures seven days old, and is due to the fact that the adhesion of the Portland cement to the sand is about equal to the cohesive strength of the particles of Ec'Sendale cement, until the amount of sand exceeds six times thafc of the Portland cement, when the adhesive strength of the sand mixture, in consequence of its porosity, falls below the cohesive strength of the two cements. 86. The crushing strength of neat Portland cement, seven days old, is not quite four times as great as that of neat Eosen- dale, both being mixed rather dry, and rammed. If both are made plastic, like mortar, the former is nearly twenty times as strong as the latter. Mixed with different proportions of sand, like beton agglo- mere, the crushing strength of Portland cement is from 6 to 12 times as great as Eosendale siuularly treated, and from 16 to 19 times as great when both are made soft, like mortar. 87. The cost of Portland cement in l^ew York, inclusive of custom-house duties, is about fifty per cent, greater than that of Eosendale cement, while for all the purposes to which cements are usually api^lied it is three times as valuable. 88. Any admixture of sand with either Portland or Eosendale cements diminishes both the tensile and crushing strength. 89. At the end of one year the tensile strength of Portland cement, mixed with an equal volume of sand, is about three- fourths of that of the neat cement. With two parts of sand, the strength is two-fifths that of the neat cement; with three parts, not quite one-third ; with four i)firts, about one-fifth ; while with five parts, of sand, the strength lies between one- ninth and one-eighth that of neat cement. 90. Sea water is nearly as good as fresh water for mixing Port- land cements, but injures the Eosendale, and all argillo-raagne- sian cements, very considerably. 91. In mixtures of Portland cement and sand for either 56 BETON AGGLOMI5E15. monolithic work or separate blocks, one-lialf the sand may be replaced advantageously by coarse pebbles, resulting in an in- crease of both the tensile and the crushing strength. 92. Neat Portland cement, mixed with to ^ of its weight, or to of its volume of common lime powder, loosely measured, loses from ^ to | of its tensile strength. Mixed with ^ its weight, or 1/^ its volume, it loses f of its strength. Mixed with f of its weight, or 2-^*^ its volume, it loses | of its strength. 93. All Portland cement mixtures acquire greater strength and hardness immersed in water than if kept in the open air. . Concrete blocks, until required for use, should be wet daily, and shaded from the sun in warm weather. A good plan, when practicable, is to make them on the beach between tides, when they will be submerged twice a day. 94. Monolithic work of Portland cement concrete in water should not be made with the best or slowest-setting cement, but with one that is more active, and the water must be perfectly quiet. The method of manipulation and treatment is the same as for Eosendale cement concrete, but the proportion of sand and ballast may be twice as great. 95. Good Portland cement weighs not less than 109 pounds to the bushel, loosely measured, is of a blueish gray color, and re- quires from three to four hours to set. The inferior cements are lighter in weight, quicker setting, and of a brownish color. The inferiority may arise from the presence of too much clay, or from inadequate burning. 96. The use of beton agglomere in France dates back to the year 1856, and confidence in its value has been constantly on the increase since that date. THE MANUFACTURE OF MATERIALS FOR BETON AGGLOMERE. 97. The prominence given in the foregoing pages to a descrip- tion of the characteristic properties of hydraulic lime and Port- land cement (the two materials upon which beton agglomere depends for its excellence) has been deemed necessary, in order that M. Coignet's processes of manufacture may be fully under- stood. The practice in France and elsewhere, wherever this beton has been introduced, requires not only that the cementing mate- rial shall possess hydraulic energy, but that this energy shall be of the peculiar kind inherent in argillaceous limestones judi- BfiTON AGGLOMfiRfi. 57 ciously burnt ; shall be, in fact, derived from hydraulic lime and Portland cement, as already described. It rejects the dolomite as a class, and all limestones largely dependent for their hydraulicity upon magnesia. It also rejects, for the reasons stated, a matrix of fat lime alone. It seems proper that the method followed at the present day, for producing hydraulic lime and Portland cement on a large scale, in order to meet the great and increasing demand for them, should now be briefly described. Nothing but a gen- eral outline of the processes in most successful use will be given. MANUFACTURE OF HYDEAULIC LIME. 98. In France, the practice of using lime that 1ms been slaked in large bulk to a state of paste, by a copious use of water, has been entirely discontinued within the last few years, for the reason that only the fat or feebly hydraulic limes can be so treated. The presence of a sufficient amount of clay to confer emi- nently hydraulic properties upon the lime, engenders the pres- ence of lumps and portions not susceptible of thorough ex- tinction by the ordinary means, which would not only render the mortar heterogeneous, but might endanger tlie stability and safety of the masonry, by subsequent slaking within the work. Hence, whenever the advantage of employing hydraulic lime, either alone or mixed with cement, in order to confer energj^ and strength upon mortar, has been recognized, the lime is in- variabl}^ used in a state of freshly slaked, impalpable powder. The use of fat lime has been very generally discontinued upon important works. 99. The following method is the one commonly practiced for obtaining hydraulic lime from argillaceous limestones contain- ing from 12 to 24 per cent, of clay, the latter being composed of about 2 of silica to 1 of alumina. The stone is burned in any suitable kiln, at a heat suflQcient to expel all the carbonic acid gas. There is no advantage in a high heat, like that necessary for burning Portland cement. While still warm from the kiln, the stone is sprinkled with from 15 to 20 per cent, of its own weight of water, care being taken not to use enough to convert any portion of it into paste. The slaking soon begins, and the stone falls to pieces, a portion 68 r * * ? \, bEton agglomEr^. /6f*it ill the fceniKitioji of fine powder, while the rest remains in • utju^aked, or ^qrtipflly slaked, lamps of various sizes. Thfe iwjidfe iirass is then thrown together in large heaps, where It remains undisturbed for six or eight days, in order to complete the extinction as far as possible, and is then screened with a sieve of twenty-five to thirty fine wires to the lineal inch. The portion which passes the screen is hydraulic lime of first quality, if the stone be capable of yielding such, and, when used, requires only sufficient water to convert it into a stitt' paste, in order to furnish an excellent matrix for mortar, beton, or concrete. The lumpy portions which do not pass the sieve either con- tain too much clay, or have been burnt at too high or too low a heat to be susceptible of thorough extinction by exposure to the air, or aspersion with water. The quantity of this lumpy- residue will be great in proportion to the amount of clay in the stone, or the extent to which the heat in burning has been improperly regulated. In some localities this residue is thrown away, as dangerous or worthless, while in others it is the custom to grind it up separately, and mix it with the powder previously obtained by aspersion. When the burning has taken place at a heat suitable for making common lime, the residue owes its origin to the presence of clay, and may be a light, quick-setting cement, like the Eoman. If so, its incorporation Avith the lime powder will augment the hydraulic activity of the latter, though perhaps not its ulti- mate strength and hardness. When the residue is too much under-burnt to slake readily, it may cause damage by a tardy extinction in the mortar, and should be rejected. When burnt at a high heat, the residue may be Portland cement, if the stone contain from 20 to 22 per cent, of clay-; or it may be inert clinker, partially or wholly vitrified, depending not only upon the amouut, but also upon the form in which the silica and alumina exist in the clay. The character of the residue, when ascertained, will deter- mine whether it would be advantageous or otherwise to add it to the lime powder produced by slaking. For these reasons the utilization of the unslaked luini)s ob- tained in the manufacture of hydraulic lime requires constant and watchfiil care, in order that the introdl^!iWi<5>f1fi^ed^HtSl that are worthless, or perhaps both dange\^y^d wortMe^, may be avoided. ^^vij? A BifiTON AGGLOMfiEfi. , MAN¥FACTUKE OF HYDRAULIC LIME AND PORTLAND CEMENT AT ONE BURNING. 100. M. Coign et has devised a method for making both hy- draulic and Portland cement, at one and the same burning, from heterogeneous argillo-calcareous limestone, in which the proportion of clay may vary irregularly from 10 to 30 per cent. Incidentally a third product (a cement inferior to the Port- land, and resembling the Eoman and the Eoseudale varieties) results from this process. The following is a condensed description of this new method : 84. The hydraulic lime, of which the process of manufacture is here described, is not similar to the article of the same name made in Austria, by burning limestones containing so large an amount of clay (generally exceeding 20 per cent.) that they can- not be slaked by aspersion with water after burning, but must be reduced to powder by grinding. The Coignet process applies to hydraulic lime derived from stone containing less than 21 to 22 per cent, of clay, which, after leaving the kiln, is slaked to powder by sprinkling with w^ater. By the usual mode described in paragraph 99, the burnt lime, after being sprinkled with water, is lirst formed into heaps to facilitate the slaking, and is subsequently screened through iine wire-cloth, the portion which passes the screen being hy- draulic lime. In operating with lime rich in clay, the unslaked, lumpy resi- due, rejected by the screen, is fret]uently so large a proportion of the Avhole as to lie a source of serious loss to the manufac- turers if thrown away, while, as already stated, all attempts to incorporate it with the powder obtained by slaking and screen- ing are attended with danger. By the new method, the lumpy portions which accumulate at each screening, instead of being ground and added to the lime powder, are, after being ground, mixed with freshly-burnt stone just before the latter is watered for slaking, so that they are again exposed to the heat and vapor developed by the slaking process. By this device those portions which would, by the usual treatment, have been liable to subsequent deleterious 60 , A ^ BfiTON AGGLOMfiEfi. action wlien niMe into mortar, become thoroughly reduced, and their presence becomes a benefit instead of an injury to the masonry into which they enter, by augmenting- its strength and hardness. Indeed, the greater the amount of residue thus treated, the greater will be the hydraulicity, and consequently the value, of the resulting product. 101. This manner of treating the pulverized residues arising in the manufacture of hydraulic lime, is one of the peculiarities of the new process. Another consists in producing, at tlie same burning, heavy, slow-setting Portland cement, as hereinafter described. 102. Hydraulic cements owe their peculiar properties to a com- bination, under the influence of heat, of a certain quantity of clay Avith oxide of calcium, producing double silicates of lime and alumina. 103. Experience has shown that the proportion existing be- tween the clay and the lime exercises a controlling influence, not only on the results obtained in burning, but on the practi- cal manipulation subsequent thereto, in order that the maximum hydraulic energy, as regards both intensity and permanence, may be secured, and the danger of tardy action in the body of the mortar lessened or avoided. In fact, when an argillaceous limestone does not contain at least 20 per cent, of clay, the lime is in excess, and no useful purpose can be subserved by exposing the stone to an excessive heat, inasmuch as the semi-fusion so characteristic of cement will not ensue, or, if apparently produced, the cement, when ground and tempered with water, will be unstable. It may, in fact, fall to pieces from the spontaneous slaking of the excess of quicklime present, this excess being the portion which has not been converted during the ctjjcination into silicate or aluminate of lime. If, on the other hand, the limestone contains more than 22 to 23 per cent, of clay, it fuses at a moderate heat, and becomes a kind of glass, destitute of useful hydraulic energy, and liable to disintegrate and fall to powder while cooling in contact with the air. If the temperature be kept so low that the stone contain- ing more than 23 per cent, of clay will not vitrify, it yields a cement of greatly inferior energy, and liable to soften when made into mortar and exposed to moisture ; while, under the same moderate heat, those portions containing 20 to 22 per cent. BfiTON AGGL0MfiRl5. 61 of clay, and therefore suitable for Portland cement, leaves tlie kiln as a liglit, quick-setting underburnt cement, or liydraulic lime, possessing not more than one-fourth to one-third of the intrinsic value of the Portland cement of average quality. 104. These light, quick-setting cemeuts are also produced by a moderate burning, from stone containing as high as 27 per cent., or even 30 per cent., of clay. Indeed, the amount of clay may reach, exceptionally, as high as 35 per cent. The cement made at Yassy, in France, the English and French Eoman cements, and all of the American cements, (the Kosen- dale, Shepherdstown, Cumberland, Coplaj^, and others,) belong- to this class. In Austria the name of hydraulic lime is given to cements of this description. The Eoman cement, made from the nodules of septaria de- rived from the Kimmeridge and London clay, is the best of the cements here referred to, though greatly inferior in strength and hardness to the Portland. 105. Experience has fully proved that the heavy, slow-setting cements (the class upon which the name of Portland has been conferred, from the resemblance of the English variety to natural Portland limestone) can only be obtained by burning, at a high heat, either limestones containing at least 20 and not more than 22 per cent, of clay, or an artificial mixture of the ingredients in similar proportions. Natural stone, suitable for this purpose, is found in Europe in the first ranf>e of the Jura formation, and on the lower slopes of the Alps in France and Austria. It generally occurs in nu- merous layers, which are very variable in the amount of clay which they severally contain, not exceeding from 10 to 15 per cent, in some, and reaching as high as 20, 25, and even 30 per cent, in others. The layers are generally thin, and there are but very few of them in which the desired proportion of 20 to 22 per cent, of clay exists, homogeneously distributed. By far the greater number contain either less or more than this amount. In whatever manner apparently homogeneous limestones may be exposed to burning, at a high temperature, it is impossible to avoid the complete vitrification of some layers containing too much clay, while others, not containing enough, or less than 20 to 22 per cent., produce cements having lime in excess. These are all more or less liable to the danger of tardy slaking, . already referred to. So great and so common is this danger, ' 62 BETON AGGLOMfiEfi. indeed, that an artificial mixture of clay and carbonate of lime lias been ver}^ generally relied upon for Portland cement. HYDRAULIC LIME AND PORTLAND CEMENT OF SEILLEY, PKANCE. 106. The argillo-calcareous deposit of Seilley, from which both hydraulic lime and Portland cement are manufactured by Mr. Coignet's method, for the Societe Gcntrale des Betons AgglomerSs of Paris, is of this heterogeneous character, comprising more than one hundred layers of stone, of very variable composition. Among these different layers the amount of clay varies from 12 to 25 per cent. In a thickness of eighty feet, comprising the useful working I)ortion of the quarry, there is an aggregate of about twenty- five to thirty feet of practically homogeneous stone, containing from 20 to 23 per cent, of clay, and therefore suitable for Port- land cement. To select and set aside these layers only, many of which are not more than four or five inches in thickness, would be impracticable. There would always be mixed up with tlie selected stone, some portion containing too much, and others containing too little clay for Portland cement. That part of the burnt product which resisted extinction by the ordinary process of sprinkling, and therefore comprising all the cement, would also contain a notable percentage of un- slaked hydraulic lime. The method devised for overcoming these difficulties consists, as already stated, in mixing the pulverized lumpy residue with freshly-burnt stone, and again subjecting it to the heat and vapor developed in slaking. By this means the superior en- ergy of the residue is utilized as far as possible, the maximum quality of hydraulic lime which the stone is capable of yield- ing is obtained, and all danger of disintegration from ulterior slaking is avoided. 107. It is to be borne in mind that Portland cement can only be made from a mixture, natural or artificial, of 20 to 22 per cent, of clay and 80 to 78 per cent, of carbonate of lime, and that the calcination must take place at a temperature suffi- ciently high to produce that peculiar softening which i)recedes incipient vitrification, it being at this stage alone that those silicates, upon the crystallization of which, in the presence of water, this cement depends for its peculiar merits, can be formed. BfiTON AGGLOMfiRfi. 63 108. In applying this method in practice, the entire product of the quarry is burnt with a heat of suflicient intensity and duration to convert those portions, containing 20 to 22 per cent, of clay, into Portland cement. The results are as follows: 1. The stone containing more than L!2 per cent, of clay would be more or less thoroughly vitrified, and would fall to powder upon cooling in the air, and could therefore be readily separated from the rest. 2. The stone containing less than 20 per cent, of clay, being the most refractory of any in the kiln, Avould remain in the con- dition of lime, more or less hydraulic, and easy of recognition and separation, in the manner hereinafter described. 3. The stone containing 20 to 22 per cent, of clay would be Portland cement clinker, requiring only to be pulverized by grinding, to complete the process of manufacture. Upon this entire product of the kiln, mixed together, enough w^ater is sprinkled to effect the slaking of the lime, and it is then formed into heaps and allowed lo remain until all portions capable of thorough extinction by the heat and vapor de- veloped, that is, all the hydraulic lime, fall into powder. The portion which resists slaking is Portland cement. The two are separated by screening, and the cement is reduced to powder by grinding. In practice it will be found that there are some lumpy i)or- tious of the slaked heaps, which, although they do not pass through the screen, are nevertheless not Portland cement. They result from the imperfect calcination of stone containing between 18 and 20 per cent, of clay, lying between the limes that slake entirely to powder, and the cements that do not slake at all. They are slaked, indeed, but not to powder, and there is no danger of any ulterior disturbance from them. The lumps are quite soft, entirely unlike the cement, and require but little power to reduce them to powder. They are pulver- ized by passing the entire residue through a mill, having the stones slightly separated from each other, so that they are reduced by a kind of rolling motion which does not crush the Portland cement. The two are separated by a fine wire screen; the powder thus obtained being a light, slow-setting cement, weighing 78 to 80 pounds to the bushel; while the Portland cement, produced at the same time, weighs 98 to 101 pounds to the bushel. 109. It is claimed that this method of treating the entire yield 64 BfiTON AGGLOMERIS. of a heterogeneous argillo- calcareous deposit, by burning it with that degree of heat required for converting into PortLand ceraeut those portions containing 20 to 22 per cent, of clay, really improves the quality of the hydraulic lime furnished by those portions containing less clay. There is no doubt that its weight is augmented, but, on the other hand, it is slightly adulterated with the dust of the vitrified stone, to which, indeed, its increased weight may be in part due. It is doubt- less a good stable hydraulic lime. It is extensively used in the vicinity of Paris, and considerable quantities have been recently imported from the Seilley works into the United States, where it has given entire satisfaction. 110. This method of manufacture, api)lied to the entire yield of the quarry at Seillej^, produces — First. Sixty per cent, of excellent hydraulic lime, weighing, uncompacted, 50 to 55 pounds to the bushel, and which, mixed into a paste with water, will set in 10 to 15 hours, and sustain a wire point one-twenty-fourth of an inch in diameter, loaded to two pounds, in 20 to 24 hours. Second. Tea per cent, of light, slow-setting cement, weighing, when not shaken down, 78 to 80 pounds to the bushel, that will sustain the same test in 8 hours. Third. Thirty per cent, of heavy, slow-setting Portland cement, weighing, when not compacted by -shaking or other- wise, 98 to 101 pounds to the bushel, that will bear the needle test in 4 hours. 111. It does not appear to be necessary at Seilley to repeat the slaking process upon any of the pulverized lumpy residue, by mixing it with freshly-burnt stone ; but that the entire product of the quarry is converted, by one burning and one sftfeing, judiciously conducted, into one or another of these three ma- terials. 112. The only works besides those at Seilley, where Portland cement is manufactured from a natural deposit, are located at Boulogne-Sur-Mer. A calcareous layer of the Kimmeridge clay, ex(;avated with pick and shovel, furnishes the material. A description of the process used at Boulogne is given in Gillmore's Treatise on Limes, &c., paragraphs 87 to 94. Some changes have been made there, however, in the practice, so that at the present time the ivet process, used in making artificial Portland cement in England, is the one followed at Boulogne. b^tH^ agglom£r£. 65 ARTIFICIAL PORTLAND CEMENT. 113. Fully nineteen-twentieths of all the Portland cement made at the present day is artificial. In its manufacture, either the loet process of England, used also in making the natural Boulogne Portland, or the dry process of Germany, may be fol- lowed. A brief and very general description of these two pro- cesses is given below. THE WET PROCESS. 114. The works in the vicinity of London employ both the white and the gray chalks of that neighborhood. Exclusive of the flint contained in them they are nearly pure carbonate of lime. The clay is procured from the shores of the Medway and Thames, and the adjoining marshes and inlets. It contains about two part^ of silica to one of all the other ingredients, comprising alumina, oxide of iron, soda and kali, carbonate of lime, &c. Mrst. The clay and the chalk are mixed together in the proportion of about 1 to 3 by weight, in a circular wash mill, provided with heavy harrows revolving on a vertical shaft, to secure the perfect reduction of the particles of chalk to an impalpable paste. The chalk is not allowed to mingle with the clay until it has passed a fine wire sieve. Second. When a thorough mixture is thus effected, the liquid, resembling whitewash in appearance, is conducted to large open reservoirs called backs, where it is left to settle. The clear water, as it rises to the surface or the heavier materials subside, is drained off. A portion of that which remains min- gled with the raw cement goes of£ by evaporation. During the time the mixture remains in the backs, samples are taken of it constantly and made into cement in sample kilns, to test the accuracy of the proportions. If any error in this respect is discovered, it is corrected by new material washed into the backs, or by mixing together the contents of two or more backs. The time required for the contents of the backs to obtain sufficient solidity to bear transportation to the drying stoves varies with the wetness or dryness of the season. Third. When the raw cement mixture has attained the con- sistency of butter, it is taken out of the backs by shovelfulls, 5 B;fiTON AGGLOMlRfi. like stiff mud, and, in that form and condition, is removed to stoves lieated by flues, and dried. Fourth. After being dried — altliougli it is not necessary to expel all the moisture — it is burnt with gas coke in perpetual bell-shaped kilns, which are fed daily from above and drawn below. The coke and raw cement are put into the kiln in alternate layers, in the proportion of about one part by weight of coke to two of cement, and the burning niu&t be carried to the point of incipient vitrification. When properly brimt the pieces of cement called clinker, are of a greenish color, and are cracked, contorted, and much shrunken from the effects of the heat. Fifth. The cement clinker is ground between millstones to that degree of fineness that when passed through a No. 30 wire sieve, of 3G wires to the lineal inch, there shall not be a residue exceeding 10 per cent. Sixth. The cement powder poured into a measure, and not com- pacted by shaking or otherwise, should weigh not less than 106 pounds to the struck English bushel. Some engineers exact 110 pounds per bushel. Seventh. Made into a stiff paste without sand, and immersed in water within twenty-four hours thereafter, the sample, when seven days old, should sustain a tensile strain, varying with the different uses to which it is to be put, of from 178 to 222 pounds to the sectional area of one inch. Few cements weighing less than 100 pounds to the loose bushel will sustain this test. THE DRY PROCESS. 115. By this process any of the compact limestones, as well as the chalks and marls, may be employed for Portland cement. It is well to remember in practice, however, that the consump- tion of power required to reduce the hard carbonates to powder, places them under a great disadvantage in neighborhoods where chalk or soft marl abounds. First. The raw materials — both carbonate and clay — are kiln-dried at 212° Fahrenheit, in order to expel the moisture and prevent caking in the mill, and otherwise facilitate grinding and sifting. Second. After drying, the clay and carbonate of lime are mixed together in suitable proportions and reduced to a fine powder. In most localities the proportion will be between BfiTON AGGLOM^Rfi. (57 the limits of 20 to 23 per cent, of clay, to 80 to 77 of the carbo- nate. One kind of machine will not snffice for grinding the raw materials economically. In the German maunfactories three are used, viz : First. A stone-breaking machine, of the kind usually em- ployed for breaking stone for roadways, or for concrete. Through this the dried and mixed materials are passed, issu- ing therefrom in pieces not exceeding the size of a walnut. Second. A further reduction is effected by a vertical mill or edge runners. Third. The material is ground between horizontal millstones to a powder of such degree of fineness that 90 per cent, of it should pass a wire screen of eighty wires to the lineal inch. Third. The powdered material is then formed into a rather stiff paste in a brick-making machine, and made into bricks of suitable size for burning. During this operation there is an advantage in keeping the mixture warm, which may be done by coils of steam pipes or otherwise. The liquid which is added to the powder in the brick machine to form the paste is made by adding to 100 ponnds of water, 2i to 6 ponnds of calcined soda, and 5 or 6 pounds of newly burnt slaked chalk or lime. This mixture is kept hot in a sheet-iron vat containing a coil of steam pipe in the bottom. It is kept thoroughly mixed by a revolving vertical shaft with horizontal arms. One hundred parts of the raw powder requires from 30 to 35 parts of this liquid. Fourth. The bricks are dried by artificial means, and are then burnt at a high heat and ground to a fine powder, as in the wet process. The same number -of mills are necessary for grinding the cement, as are used in pulverizing the raw materials. The clinker is first put into a stone-breaking machine, then into a vertical mill, and, lastly, is ground to an impalpable powder in a horizontal mill. 116. In the largest and best-managed manufactories of Port- land cement in Europe, in which none but a first-class article is produced, there is always a competent chemist employed to make daily trials of the materials on a small scale, in order that any departure, however slight, from the best proportions of the ingredients, may be averted before it can occasion any serious injury to the average quality of aggregate yield. An 68 BfiTON AGGLOMErE. active competition in tlie bnsiness has rendered it necessary to leave nothing to the results of chance. KILNS FOR BURNING PORTLAND CEMENT. 117. The most difficult part in the operation of making Port- laud cement, hy either process, is the proper application and management of the heat in burniug. It is an easy matter to pulverize and mix the raw materials when either wet or dry, and to grind the burnt stone to a fine powder. But the mysterious conversion which takes place in the kiln, under a heat of suffi- cient intensity to make glass, is to a great extent beyond our knowledge, and to some extent beyond our control. 118. All the manufactories in Germany, with one or perhaps two exceptions, burn the cement in intermittent kilns, which are about 50 feet high and 10 feet in greatest diameter. The kiln is filled with alternate layers of raw cement and coke, or coal, and then fired. About three days are required for the burning, and from five to eight days for the kiln to cool off so that it can be drawn. These kilns, judged by the quality and quantity of their yield, are the most expensive kind that can be used. They are no improvement upon those in use one hundred years ago, and require the most skillful management and supervision to produce even moderately fair results. 119. The perpetual bell-shaped kilns used in England and at Boulogne, although superior to the intermittent German kilns, fall far short of satisfying the essential conditions of a good kiln. They consume too much fuel, the control of the com- bustion is attended with considerable difficulty, and the results are liable to be to some extent uncertain. THE ANNULAR KILN. 120. The annular or ring kiln, in which the burning cham- ber is placed around the circumference of a circle, ellipse, or oval, is doubtless, in one form or another of its several modifi- cations, the best that has been yet devised for burning either cement, lime, or bricks. 121. The Hoffmann Jciln, considered as a type of this class, is not, perhaps, inferior to any of the others, and will be briefly described. (See Plate IX.) DESCRIPTION or THE HOFFMANN KILN. 122. Imagine a railway tunnel, 8 to 9 feet high, by 10 to 12 feet span, constructed round a circle or an oval of such dimen- BfiTON AGGLOMfiRfi. 69 sions that, measuring round the middle line of the annular cham- ber thus formed, the periphery is about 350 feet. This annular tunnel is called the burning chamber. In the centre of the space enclosed by the ring, is a long chamber called the smoke chamber, leading to a chimney 140 to 150 feet in height. This chimney may stand within the central space, or exterior to it. In the latter case a smoke flue would lead from the smoke chamber, under the burning chamber, to the base of the chim- ney. Fourteen radial flues, at equal intervals, lead from the burning chamber to the smoke chamber, each provided with a bell-shaped damper, which may be opened or closed, as required. There are fourteen doorways through the outer wall of the burning chamber, each 5 feet in height by 4 feet wide, placed at regular intervals. The arched top of the burning chamber is pierced at intervals of 3 to 4 feet, with holes about 5 inches in diameter, called the feed holes, which are used for supplying the fires with fuel. There are about 300 of them, each closed with a bell-shaped cover fitting over a rim or curb, and dipping into sand. The whole should be substantially built of stone or brick masonry, and covered with a permanent roof. The burning chamber should be lined with fire-bricks when the kiln is intended for burning cement. 123. Manner of using the kiln. — Let the doorways be num- bered from 1 to 14, counting from left to right as you enter a doorw^ay, and let the fourteen flues be numbered in the same manner. When the kiln is in operation, all the doorways but two, or exception allj^ three, are kept closed with temporary brick- work. Sujipose only 1 and 2 to be open. Workmen are engaged in taking burnt lime from doorway No. 2, and others in conveying raw limestone in at doorway No. 1, and piling it up in the burn- ing chamber, leaving vertical openings under the feed holes and horizontal passages for draught, parallel to the periphery. It is convenient to call each portion of the burning chamber between two consecutive doorways a compartment, although there is no permanent division of the burning chamber into smaller chambers. When the kiln is in operation, usually all the compartments but two are filled with cement stone, in all stages from raw stone to thoroughly burned cement. Suj^pose compartments 1 and 2 empty, and all the others filled. No. 3 contains cement 70 BfiTON AGGLOMfiRfi. from stone put in 12 days ago; No. 4 that from stone put in 11 days ago ; and so on around to compartment 14, which w:as filled yesterday. Separating No. 14 from No. 1 is a sheet-iron parti- tion, as nearly as possible air-tight. This partition, called the cut-off, is movable. Yesterday it was between 13 and 14 ; to- morrow it will be between 1 and 2, and so on, being moved on one compartment each day. All the dampers are closed to-day except No. 14 • yesterday all were closed except No. 13 ; to-morrow only No. 1 will be open. To-day men are removing burnt cement from compartment No. 2, and others are setting raw stone in compartment No. 1. Yesterday they were setting stone in No. 14, and removing cement from No. 1. To-morrow they will be removing cement from No. 3. and filling No. 2 with raw stone; so that every day the setting, drawing, cut-off, and open damper advance one compartment. The fires are in the centre of the mass, from the burnt cement end round to the raw stone end ; say in compartments 7 and 8 to-day, 6 and 7 yesterday,, 8 and 9 to-morrow, advancing one compartment per day, like the drawing and setting. The compartment that was in fire yesterday, say No. G, is still very hot to-day, No. 5 less hot. No. 4 cooler, and so on to No. 2, where the cement is cool enough to be handled, and men are removing it from the kiln, wheelbarrows, or trucks on portable railway tracks, being used for the purpose. The compartments not yet fired are heated by the hot gases passing through them to the chimney, the stone in the com- partment next the fire being at a full red heat, while that farthest off, which was put in yesterday, is only warm. The draught of the chimney is sufficient to draw air in at the open doorways, through the entire mass of cement and raw stone, to the open flue, which is the one by the cut-off. In passing through the burnt cement, the air takes up the residue of heat and becomes hotter and hotter, till, after passing through the cement burned yesterday, the hot current ignites at once the dust coal as it fiills from the feed pipes, and the gases thus formed being carried on, mixed with air, it is proba- ble the stone is burned considerably in advance of Avhere the coal is supplied. As the hot gases of combustion pass on, they give up their heat to the limestone, till, on arriving at the chimney, there is only heat enough remaining to cause a draught in a well-constructed chimney 140 to 150 feet in height. It is plain that all the heat BfiTON AGGLOMfiRfi. 71 of combustion is utilized, except sucli as may escape tlirougli the walls of the kiln, and as the masonry is very massive, the loss from this cause is very slight. 124. One peculiar feature of these kilns is, that although less likely to get out of order than other kilns, from the fact that there is no movement in the burning mass, repairs may be easily made without letting the fire go down. There are Hoffman kilns in which the fires have not been ex- tinguished for five years. One like that above described, operating at Llandulas, Wales, produces about 80 tons or 650 barrels of common lime per day, at a cost of 5s., or $1 25 gold, per ton — estimating the unquar- ried limestone as of no value — as follows : s. d. Getting stone, including tools 1 3 Setting 0 5 Drawing 0 3^ Burners' wages 0 3^ Fuel, at 7s. j)er ton 1 6 Cost of producing lime 3 9 To which is added 33 per cent- for all expenses of management, & c ... 1 3 5 0 Making entire cost per ton 5s., or $1 25 gold. The lime sells at the works for 7s. per ton, ($1 75 gold.) The work is generally done by the ton, and at the above prices the men make from 3s. to 4s. (75 cents to $1 gold) per day. 125. At Mexham, near Chester, England, the cost of pro- ducing lime is the same as the above. 120. At Settle, in Yorkshire, where there is a Hoffmann kiln jpf about the same size, the setting, including running in the loaded trucks and running out the empty ones, costs sixpence per ton of lime, the drawing twopence per ton, the men earning from 3s. to 3s. 6d. per day. 127. At the current prices of labor and fuel in the United States, lime could be manufactured in a Hoffmann kiln at about $2 per ton, or between one-fourth and one-fifth of its present cost to consumers. The details of cost may be liberally stated tis follows: Cost of quarry and plant 120,000. Annual yield of kiln 20,000 tons. 72 BfiTON AGGLOMfiRfi. Co8t 2)er ion. Interest on investment |0 07 Qnairying 65 Setting in kiln 20 Drawing 15 Burners' wages , . 15 Fuel , 43 Contingent expenses, 20 per cent 33 Cost of making one ton of lime 198 128. At Bieberich, on the Rhine, a Hoffmann kihi is used for burning artificial Portland cement. The quantity of fuel con- sumed is 77 pounds to the cask of 410 pounds. The cement is of excellent quality. There is no chalk in the neighborhood, and hard limestone has to be used in its stead. 129. The cost of manufacturingPortland cement in Germany, all contingent expenses included, generally varies from $6 GO to $6 70 (gold) per gross ton, and it is sold at a net profit of 40 per cent, on the outlay. 130. In the United States the cost would not vary greatly from $10 per gross ton, the works being located at the point of supply of the limestone, as follows : Estirmted cost of malcincj Portland cement in the United States lnj tlie dry process, using hard limestone and a Hoffmann kiln. Annual capacity of Avorks, 30,000 barrels, or 6,000 tons. Interest on $40,000 investment |2, 800 9,000 tons iSbTf limestone, delivered, at $1 50 13, 500 2,800 tons clay, at $1 40 3, 920 1, 100 tons pea and dust coal, at $4 30 4, 730 Salary of snperintendeut 2, 000 Salary of forem an 1,200 Thirty-eight laborers, at $45 per month, average 20, 520 Two burners, at $75 per month 1, 800 Contingencies and wear and tear, 20 per cent, on above, except the interest 9^ 534 Total cost of manufacturing 6,000 tons 60, 004 / = Cost of manufacturing one ton $10 This estimate is believed to be a liberal one. It shows that Portland cement can be manufactured in this country at a cost less by from 12 to 14 per cent, than the wholesale market price of Eosendale, omitting the cost of barrels in both cases. The Portland cement weighs 410 pounds and the Eosendale 310 iDounds to the barrel. THE EANSOME STONE. 73 131. There are nearly six hundred Hoffmann kilns in operation in Europe, varying in size from the one above described, capa- ble of producing 20,000 tons of lime per annum, to kilns of one-eighth or even one-tenth of this capacity. Whether used for burning cement, lime, or brick, they give (qual satisfaction, in respect to ease of management, economy of fuel, and uni- formity of results. EANSOME'S PATENT SILIOIOUS OONOEETE STONE. 132. The process for making this stone followed at the pres- ent day vy^as patented by Mr. Frederick Kansome, of London, in the year 1856. It rests upon sound scientific principles, and in practice consists in forming in the interstices of sand, or any pulverized stone, a hard and insoluble cementing substance or matrix, by the mutual decomposition of two chemical compounds in solution. The compounds employed are : Silicate of soda ("soluble glass," "liquor of flints," "flint soap"), and chloride of calcium. These when mixed together form, almost instantaneously, by mutual or double decomposition : Silicate of lime, and chloride of sodium (common salt). 133. The value of the artificial stone thus produced depends tj.pon the strength, hardness, and durability of the silicate of lime which binds the sand together. This is one of the compounds always formed during the set- ting of hydraulic limes and cements derived from the argilla- ceous and argillo-magnesian limestones, and upon which they largely depend for their value. 134. The process followed in manufacturing Kansome's stone, although attended by considerable labor, is exceedingly simple in theory. The raw materials employed are principally sand, gravel, flints, chalk, limestone, caustic soda, chloride of calcium and water. The sand may be coarse or fine, or a mixture of both, depending on the fineness of texture aimed at. Pow- dered chalk or limestone is generally mixed with the sand when a smooth surface and fine grain are required. The silicate of soda, or " flint soap," is made by boiling and dissolving flints in a strong solution of caustic soda under pressure. In order to secure the best results, as well as for convenience 74 THE EANSOME STONE. of manipulation, it should be of the consistency of molasses, although more tenacious, and possess a specific gravity of about 1.7. To every bushel of sand about one gallon of the prepared silicate of soda is added, and the whole mass is then thoroughly mixed together in a mill, until it attains a putty-like semi-plastic condition, fit for ramming or compacting into moulds. With a suitable mill the mixing of each charge or batch re- quires but four or five minutes. The prepared material is then pressed into moulds of wood or metal, by suitable implements, or it may be rolled into slabs, when that form is required, as for roofs, pavements, etc. The slab as soon as formed, and before the process proceeds further, may be cut into pieces of any shape that shall adapt it to the use to which it is to be applied. When the material is once formed in moulds, it may be taken out immediately, and is not liable to warp or crack, or undergo any subsequent change of form. The moulded blocks are at once drenched with a solution of cold chloride of calcium, which acts rapidly upon the silicate of soda, and hardens and solidifies the mass to that degree that it can be removed and handled without danger of breaking, during the subsequent steps of the process. They are then conveyed into cisterns containing a solution of chloride of calcium of about 1.4 specific gravity, and a temperature of about 212° Fahr. In this bath the chemical action is completed, and results in the formation of an insoluble silicate of lime through the mass, en- veloping and cementing together the particles of sand, gravel, powdered limestone, etc., of which the block is composed. After the blocks have been saturated with the hot chloride of calcium, the completion of the process consists in washing away the chloride of sodium or common salt, evolved by the combination of the sodium with the chlorine. This is accomplished by thoroughly drenching the blocks with cold water for a longer or shorter time, depending on their size. The work is then finished and the block ready for immediate use. 135. An essential condition of success is, that the bath of hot chloi-ide of calcium shall be applied while the silicate is still moist, or, in other words, as soon as the material is moulded into form. When thus applied, the double decomposition takes place, nearly, if not quite uniformly, throughout the entire mass. The blocks may be as large as can be conveniently handled. Were the moulded blocks allowed to dry before the application of the THE EANSOME STONE. 75 cliloricle, the pores at the surface would be closed with silicate of lime, and the further penetration of the solution thereby im- peded. 136. It would appear impossible, in the absence of positive knowledge to the contrary, that the chloride of sodium could be washed out from the interior of larged-sized blocks, by the most thorough and prolonged drenching with water; and admitting such result to be attainable, it would seem to prove the stone to be exceedingly porous. In practice, however, it has been found that the water does seek outlet, and carry off nearly all the salt in the form of brine, and that the stone becomes, in a few hours-, as nearly impermeable to water as most of the varieties of natu- ral sandstones. PROPERTIES OF EANSOME'S SILICIOUS STONE. 137. The porosity and the percentage of degradation from various causes, of the Kansome stone, and of several natural building stones, were ascertained in 1861 by Dr. Edward Frank- land, F. R. S., &c., &c.. Professor of Chemistry at the Royal In- stitution, London. The specimens of the Ransome stone experi- mented on were two weeks old. The following is extracted from Dr. Frankland's report, dated December 21, 1861 : "I have submitted to experimental investigation samples of stone forwarded to this laboratory, and have now to report as follows : " The experiments were made in the following manner : The samples were cut as nearly as possible of the same size and shape, and were well brushed with a^hard brush. Each sample was then thoroughly dried at 212°, weighed, partially immersed in water until saturated, and again weighed ; the porosity or ab- sorptive power of the stone was thus determined. " The sample was then boiled with water until all acid was re- moved, and again weighed. Finally it was dried at 212**, brushed with a hard brush, and the total degradation or loss since the first brushing was ascertained. The following numbers were obtained : 76 THE EANSOME STONE. Percentage alteration in weight by im- mersion in dilute acid. entage ion of lubse- ing in 7i "3 Name of Stone. Porosity — centage of absorbed I stone. Of 1 per cent. acid. Of 2 per cent. acid. Of 4 per cent. acid. Total perc loss by act acid and s quent boil water. _o a Total degr tion from causes. Loss. Gain. Loss. Gain. Loss. I Gain. Fur Bath 11.57 9.86 1,28 2.82 2.05 ! .. 5.91 .26 6.17 2.13 4.80 .67 ; .. 11.73 1.60 13,33 4.15 1.18 4.00 . . 1 04 3.56 .29 3.85 8.86 1.60 1.10 1.35 ! .. 3.94 .24 4.18 6.09 3 52 3.39 3.11 i .. 11.11 .27 11.38 Whitljv 8.41 1.07 .53 None. 1 None. L25 .18 1.48 Hare Hill 4.31 .75 .60 None. None. .98 .15 1.13 Park Spring . . . 4.15 .71 .10 .81 None. .81 Ransome'sPatent 6.53 .95 None. None. None. None. i .63 .31 .94 The results furnished by the foregoing table are so easy of in- terpretation, that Dr. Frankland's remarks thereon are omitted. Dr. Charles T. Jackson, State Assayer of Massachusetts, found the absorbent power for water of the Ransome stone, when treated first in vacuo, and then under atmospheric pressure under water, to be 15^^% per cent, as the mean of three trials. Another sample made under different circumstances, but treated similarly, absorbed 17 per cent, of water. He says the stone " is as firm as any sandstone used in this country, and possesses no more absorbent power." 138. Strength. — Ransome's stone possesses, with a liberal factor of safety, ample strength to resist all the strains to which it would ordinarily be subjected as a building material. 139. D. D. Ansted, Esq., F. R. S., Professor of Geology at King's College, London, submitted a paper at a meeting of the British Association, at Cambridge, in 1862, which furnishes the following extract : " The Transverse Strength. — A parallel bar of Ransome's con- crete stone, measuring 4 in. by 4 in., and resting upon iron frames so as to bear one inch on the iron at each end, with 16 inches clear between the supports, sustained a weight suspended from the centre of 2,122 lbs. ; a bar of natural Portland stone of the same dimensions, treated similarly, broke at 759| lbs." Tensile Strength or Adhesive Power. — The tensile strength was determined by tests applied to pieces of stone, having a sectional area of 5| square inches at the weakest point, and suitably notched near the ends so as to be embraced by clamps. THE EANSOME STONE. 77 The following results were obtained : Specimens of Stone Tested. Area of Cross Sec- tion. Total Tensile Strength of Block. Tensile Strength per square inch. 1. Eansome's Patent Stone ... . 2. Natural Portland Limestone 5^ square inches 5i " 5^ " 5^ " " 1,980 lbs. 1,104 " 796 " 768 " 360 lbs. 201 " 145 " 140 " A 4-inch cube of Eansome's stone was found to sustain a weight of 30 tons before it was crushed, equal to a strength to resist crushing of 4,200 lbs. to the square inch. Both the transverse and the tensile strength of the Eansome stone, given above by Professor Ansted, are much greater than the results obtained by Mr. G. M. WilUams, of Hale CHff, Eng- land, from the same kind of stone manufactured by himself, and reported in a paper read at the meeting of the Liverpool Archi- tectural Society, December 27, 1865, as follows : STEENGTH OF EANSOMe's PATENT CONCRETE STONE, MANDEACTUBED BY G. M. WILLIAMS, OF HALE CLIFF, ENGLAND. 140. " Comparative trials of the strength of the above stone, and of some of the natural stones in use for building in the Liverpool district, were made October ], 1864, at Hale Cliff, England, in presence of several of the architects of Liverpool and other gentlemen. " The blocks of stone used for testing the transverse strength were 4 inches square (in cross section) and 18 inches long, and were supported upon bars an inch from each end, giving a bear- ing of 16 inches, and the weight was applied to the centre. "The pieces used for testing the adhesive power (or tensile strength) were bars having a sectional area of 5| square inches, with projections at the ends to allow of their being torn asunder. " The comparison between the natural and artificial stones, as to their power of absorbing water, showed that there was little difference, the artificial stone, made with coarse sand, taking up about the same quantity of water as the coarse-grained natural stone, and that made of the fine sand taking up about the same as the fine-grained natural stones. The water absorbed ranged from 12| per cent, taken up by the coarse-grained stones, to 78 THE EANSOME STONE. 6^ per cent, taken up by those of fine grain. The stones were all thoroughly dried before being placed in water." TEIALS OF TKANSTEKSE STRENGTH, SHOWING THE BEEAKING -WEIGHTS. Red Sandstone, 16 ins. clear, 4"X4". Stourton, 16 ins. clear, 4"X4". Minera, 16 ins clear, 4"X4". Freestone, kind unknown, 16 ins. clear, 4"X4". Patent Concrete, 16 ins. clear, 4"X4". 10 cwt. This stone was from Woolton quarry, and has been exposed to the air for manjyears 7 cwt. 6} " Coarse, 7 cwt. Fine, 8 " 121 cwt. 12^ " 12 cwt. 11^ " 15 " 12 " 6i 7i m m Two other blocks of a fine-grained heavy stone of the same dimensions, supposed to be from Yorkshire, broke at ITg and 211 cwt. On the 26th of November, 1864, a further number of blocks of concrete stone of the same size were tested, when the breaking weights ranged between 11 and 14|- cwt. Two similar blocks, made of sand, now (December, 1865) used at the Hale Cliff Works, were lately tested, and the breaking weight was 16| and 17| cwt. Four blocks of concrete stone, of the same size, of the quality prepared for filters, very open and porous, were tested, and the breaking weights were 9f , 9f , 9, and 11 cwt. TRIALS OF ADHESIVE POWER OB TENSILE STRENGTH, SHOWING THE BREAKING WEIGHTS. Sectional Area, b\ Square Inches. Stourton, Under 3>^ weight. Minera, Under 3}4 c^'t- Freestone, kind unkn'n, Raxsome's Stone. Total Strength. Tensile strength pr. sq.in. This was the smallest weight which the arrangement of the machine admitted of applying, and on trial it was obvious that this was considerably more than either stone would bear. 4% cwt. 9 " 5 " 5% " 5h " 7^ " 87 lbs. 183 " 102 " 117 " 117 " 153 " 6| Over 6i cwt. THE EANSOME STONE. 79 141. The age of the specimens of Eansome's stone above named is not given, from which it may be presumed that they were con- sidered to have attained the maximum strength. They possessed about the same crushing and tensile strength as beton Coignet of good quality, ten months old, or that of medium quality, suitable for plain walls, when twenty months old. Good beton Coignet ultimately attains nearly twice the crush- ing strength of the Kan some stone tested by Professor Ansted. 142. An article in the London Engineering, for June 28, 1867, reports the trials of blocks of Eansome's stone and of Bath stone with the following results : STRENGTH TO KKSIST CEUSHING. Kinds of Stone Tested. Size of Blocks. Total Crushing Weight. Crushing Weight per square inch. 1. Ransome's Concrete Stone 2. Ransome's Concrete Stone. 4" X 4" X 4' 4" X 4" X 4" 4" X 4" X 4" 48 tons. 44 " 14 " 6,720 lbs. 6,160 " 1,960 " TENSILE STRENGTH, OB ADHESIVE POWER. Area of Cross Section. Total Tensile Strength of Block. Tensile Strength per square inch. 1. Ransome's Concrete Stone. 2. Ransome's Concrete Stone. 2 J square inches. 2| square inches. 870 lbs. 1,200 " 386 lbs. 533 " 143. By a comparison of the foregoing tables made up from all the experiments known to have been published up to the present time, and assuming them to be trustworthy, it will be seen that the tensile strength of Eansome's stone is extremely variable, ranging from 97 pounds to 533 pounds to the square inch. Its strength to resist crushing, obtained with 4 -inch cubes, reaches as high for the best specimens as 6,720 pounds to the square inch, or about twelve times the tensile strength per inch of the same material. 144. The crushing strength of the weakest specimens reported — that giving a tensile strength of 97 pounds to the inch — would probably not exceed 1,200 to 1,500 pounds to the inch on 4-inch cubes. The crushing strength of beton Coignet of best quality, two 80 THE EANSOME STONE. years old, reaches as high as 7,500 pounds to the square inch, while for ordinary qualities, suitable for foundations and massive walls, a lower standard of strength, and consequently a reduc- tion in the cost, is at the option of the builder, by increasing the proportion of sand. 146. The crushing strength of the beton Coignet, used in the church at Vesinet, near Paris, was only 2,634 lbs. to the square inch, which was regarded as ample for the purpose. 147. In making comparisons of strength it should be remem- bered that Ransome's stone does not materially improve in strength and hardness after it is a few weeks old, while beton Coignet, and indeed all mixtures of hydraulic cement or hydrau- lic lime and sand, continue to indurate for a period of two to two and a half years, and require fully three months to acquire one-third of their greatest attainable strength. 148. The Ransorae stone, in consequence of the necessity for immersing the moulded blocks in a bath of hot chloride of cal- cium, is, of course, not adapted to monolithic construction, in which the beton Coignet finds its most advantageous applica- tion. The former, however, has this advantage, that the stone will bear transportation as soon as made, while the Coignet piece woi-k must remain undisturbed for at least two days, even for small blocks, and a longer period for larger ones. 149. The labor expended in the making, costs much more than that required for beton Coignet, even in blocks. The measuring, mixing, and moulding into form, of the materials, and the re- moval of the block from the mould, are operations necessarily common to the two processes; but that of Coignet is completed here, while by Ransome's the moulded work must next be drenched with the cold chloride, then placed in a hot chloride bath, and subsequently removed therefrom and drenched with water before the stone is finished. 150. The Ransome stone is adapted to many descriptions of architectural embellishment, such as cornices, capitals, door and window dressings, copings, balusters, finials, &c. ; for garden de- corations, such as fountains, vases, statues, gate piers, balus- trades, borders, &c. ; for steps, pavements, grindstones, slabs, tiles, &c. ; for monuments, tombs, gravestones, and other cemetery requirements. 151. The " Patent Concrete Stone Company," operating the Ransome process, have extensive works at East Green wich, near London, where work of almost any pattern can be procured. THE RANSOME STONE. 81 The manufacture of grindstones has become a very important branch of the business ; 19 different sizes are made, ranging from 1 foot to 6 feet in diameter, and from 2 inches to 12 inches in thickness. The retail prices vary from 70 cents gold, for a stone 12 inches diameter and 2 inches thick, to $76-jaA_. gold, for a stone 6 feet in diameter and 1 foot thick, equal to about $2^^yO_ per cubic foot, with an extra charge in all cases for packing. The medium sizes sell for about $2.00 per cubic foot. These grindstones, being perfectly uniform in hardness, and homoge- neous in structure, have been found to be greatly superior to those made from the best natural sandstones of England. They pos- sess the additional advantage, that by a judicious selection of the sand of which they are made, their grain and texture can be specially adapted to any particular class of work. 152. Competitive trials of Mr. Ransome's artificial grindstones and natural Newcastle stones were made in England by Messrs. Ryan, Donkin & Co., early in 1867, with the following results : A bar of steel | in. in diameter, was placed in an iron tube containing a spiral spring, and the combination was then ar- ranged so that the end of the bar projecting from the one end of the tube barely touched one of .the artificial stones, whilst the other end of the tube rested against a block of wood fixed to the grindstone frame. A piece of wood of known thickness was then introduced between the end of the tube and the fixed block, and the spiral spring being thus compressed, forced the piece of steel against the grindstone. The same bar of steel was afterwards applied in the same way, and under precisely the same pressure, to the Newcastle stone, and the times occupied in both cases -in grindilig away a certain weight of steel from the bar were accu- rately noted. The results were that a quarter of an ounce of steel was ground from the bar by the artificial grindstone in sixteen minutes, whilst to remove the same quantity by the Newcastle stone occupied eleven hours; and this, notwithstanding that the surface speed of the latter was more than 20 per cent greater. Taking the 20 per cent, greater speed of the Newcastle stone into account, it will be seen that the 11 hours run by it were equal to 13 1 hours at the same speed as the artificial stone, and the proportional times occupied by the two stones were thus as 16 minutes to 13| hours, or as 1 to 52 nearly ! 153. The retail prices of Ransome's stone at the works, in 82 THE EANSOME STONE. blocks containing from 1^ to 3 cubic feet, according to tlie pub- lished price list are — For plain building blocks, $1.50 gold, per cubic foot. For plain rustic coins with chamfered corners, $1.55 per cubic foot. For " " with ornamented face, $1.70 to $1.85 " 154 M. Coignet's price list shows that similar work is deliv- ered at his manufactor}^ at St. Denis, for from 65 to 70 cents per cubic foot. Either Company would doubtless undertake large contracts at a reduction of perhaps 30 per cent, on these prices, while massive monolithic constructions, to which the Eansome stone is not applicable, can be executed in France in be'ton Coig- net with a fair profit at from 25 to 30 cents per cubic foot. Stones for architectual and other kinds of embellishment, of course cost more than the prices above quoted, both at St. Denis and at Greenwich, depending on the degree of ornamentation required, and the kind of mould necessary to produce it, the most expen- sive work being that which requires plaster moulds in many pieces. 155. Ransome's process for hardening and preserving stone, brick, etc. — Mr. Ransome has applied to the hardening and water-proofing of soft and porous stone, bricks, stucco, &c., the same principle upon which his manufacture of artificial stone rests for its novelty and value, and he employs the same chem- ical compounds in the one case as in the other. 156. Inasmuch as no engineer or architect would, knowingly, construct in stone or bricks of such inferior quality as to require the use of artificial means of preservation from decay, this hard- ening process finds its application limited to walls and buiklings already constructed. 157. The process is described in general terms in paragraph 600, Gillmore's Treatise on Limes, Hydraulic Cements and Mor- tars, and consists in first washing the stone thoroughly with a solution of silicate of soda, and afterwards with a solution of either the chloride of calcium or the chloride of barium. The calcium solution is in most general use. In order to insure suc- cess the following rules should be observed : 1. The surface of the stone, &c., should first be thoroughly cleaned by the removal of any extraneous matter, and should also be perfectly dry before being operated on. 2. The prepared silicate of soda should be diluted with water (soft or rain water where convenient), in such proportions as may be necessary to admit of its being absorbed freely into the THE RANSOME STONE. 83 structure of the stone or bricks, &c. If the material be of a very absorbent character, about an equal quantity of water will be found sufficient; but if of a close or dense texture about two parts of water, or in some cases even three parts of water should be mixed with one of silicate. The prepared silicate, diluted as above, should be applied freely, but evenly, by means of a brush, to the surface of the stone, &c., and when propeiiy absorbed, the operation should be repeated until the stone, &c., is thoroughly charged ; but care must be taken not to allow any excess of silicate to remain upon the face when dry. 3. After a day or two when the silicate has become perfectly dry the prepared chloride of calcium should be applied freely (but brushed on lightly), so as to be absorbed with the silicate inlhe structure of the stone, when a double decomposition will immedi- ately take place, and an insoluble silicate of lime will be precipi- tated, filling up the pores of the stone or other material, and firmly aggregating and cementing together the various particles of which the same may be composed. 4. In some cases it may be desirable to repeat the operation, and as the precipitate thus formed by these two solutions is white or colorless, in the second dressing the prepared calcium should be tinted to produce a precipitate to harmonize with the natural color of the stone. 158. The wholesale price of silicate of soda, in London, is about $1,371 per gallon, gold, and of chloride of calcium $1.12| per gallon. The tinting solutions cost from 85 to 90 cents per pint. 159. This preserving process has been applied to quite a number of buildings, as well as to monuments, tombstones, &c., in England and the East Indies, and although its success has not in all cases been so decided as to command uniform approval, it is very generally admitted, by those familiar with its use and history, to be a valuable invention. No soft and porous stone can be properly treated by it without positive benefit. It hard- ens and strengthens the stone, renders it more nearly impervi- ous to water, and does not occasion unsightly effervescence upon the surface if properly applied. 160. Its power of rendering brick walls practically waterproof, gives it great value in localities destitute of low-priced building stone. 84 THE FREAR STONE. THE FREAE ARTIFICIAL STONE. 161. In 1868 Letters Patent were issued' in tlie United States to Mr. George A. Frear for " Improvement in composition for artificial stone, stucco, &c." 162. The only peculiar feature claimed for Mr. Frear's process is the use of gum shellac for increasing the strength and hard- ness of the artificial stone, stucco, etc., to which it is added. In its application to artificial stone the shellac is added to a mixture of hydraulic cement and sand in the following manner: 163. The cement is incorporated with the sand while dry in such proportions as shall completely fill the voids — say one measure of cement, not compacted, with two and a half measures of sand — and the mixture is then moistened with a solution ob- tained by dissolving one pound of gum shellac in two to four ounces of concentrated alkali in aqueous solution. This is diluted with water to that degree that about one ounce of the shellac is distributed through the cement and sand used in making one cubic foot of the stone. The dampened mixture, after thorough incorporation, is placed in strong moulds of the rec^uired form, and subjected to heavy pressure by machinery. The amount of pressure varies from fifteen to twenty-five tons per block, depending on the size of the latter. On being taken from the mould, which may be done at once, the block of stone is allowed to dry two or three days, and is then dampened and exposed to the atmosphere, where the hard- ening process goes on. Ordinary blocks, such as sills, steps, &c., may be used in two or three weeks. 164. The pressing machines designed by Mr. Frear are of three sizes, as follows: No. 1 will press a stone 12" X 28" X 6" in size, equal to 31| bricks. It will also press six bricks at a time, each 4" X 6" X 12", designed to lay a solid wall one foot thick, or by laying them six inches to thf) weather, a double or hollow wall, one foot thick, can be made, leaving the inside face in suitable condition to receive the hard finish, without the first and coarse coat of plaster. This machine, with four hands, will, it is claimed, press an amount of stone equal in quantity to from 10,000 to 12,000 common bricks per day. The price of this machine, delivered for shipment, is $300. THE FREAE STONE. 85 No. 2 will press a stone measuring 6" X 10" X 22", and No. 3 one 6" X 4" X 28." 165. The Company engaged in manufacturing stone under the Frear patent publish the following report from the Inspector of Ordnance in the Washington Navy Yard, as testimony regarding the strength and value of their stone : " Ordnance Office, Navy Yard, Washinoton, D. C, March 10th, 1869. " The following are the results of a test of building material presented by Mr. Charles Holland, of Chicago, through Mr. David A. Burr, and called by him Frear stone: Height. Base. Depth. Cube 1.27 in. X 1.30 in. X 1.29 in. Compression. Strength. 1 in 270 300 lbs. 1 " 270 1,000 " 1 " 270 2,000 " 1 " 265 3,000 " 1 " 265 4,000 " 1 " 265 5,000 " 1 " 265 6,000 " Crushed 6,050 " " The specimen is not an exact cube, as is seen above. The measurements indicate the position of the stone in the machine when crushed. " (Signed) W. R. Reese, " Commander U. 8. Navy, " Inspector of Ordnance." The results recorded in Commander Reese's report give a crushing strength of 3,607 lbs. to the square inch. This is less than one-half the strength of the best beton Coignet, tried at Paris, in July, 1864, by Mr. P. Michelot, Chief Engineer in the Fonts et Chaussees, which gave a crushing strength of 7,495 pounds to the square inch, while fourteen different qualities of beton tested by the same officer, at the same time, gave an average crushing strength of 4,670 pounds to the square inch. 166. Several two inch cubes tested by the writer in the pres- ence of Mr. Frear, in April, 1871, gave the results recorded be- low. The composition of the blocks, as reported by Mr. Frear, was one measure of hydraulic cement, two and a-half measures of sand, moistened with an alkaline solution of gum shellac, of 86 THE FEEAR STONE. sufficient strength to furnish one ounce of the shellac to one cubic foot of the finished stone. Portland cement was used in Nos. 1, 2, and 3, and Louisville cement in No. 4. The ages of the stone are those reported by Mr. Frear. No. 1. 2 inch cube, four weeks old, crushed at 18,000 lbs., or 4,500 lbs. per square inch. No. 2. 2 inch cube, " " 18,500 " 4,626 " No. 3. 2 inch cube, three -weeks old, crushed at 9,000 " 2,250 " " " No. 4. 2 inch cube, six months old " 8,000 " 2,000 " " " A four-inch cube, of the same composition and age as Nos. 1 and 2, sustained 57,000 lbs., equal to 3,562^ lbs. to the superficial inch under compression, and was not crushed. 167. Some of the Frear stone used in the construction of dwelling-houses, in Chicago and other Western localities, has not thoroughly withstood the effects of the climate. .The failures are not represented as numerous, and are by no means fatal in either extent or character, and may have been due to the use of inferior native cement. The cement, however, to which preference has generally been given, is that manufactured at Louisville, Kentucky, which, although generally somewhat inferior to the Kosendale brands, stands above the average of native varieties. No Portland cement has been employed in making Frear stone in the West. It is superior to all others for this pui'pose. The introduction of gum shellac undoubtedly adds to the strength of any mixture of hydraulic cement and sand, while that mixture is yet new, or only a few months old ; but whether it will tend to augment the strength and hardness acquired by age, particularly when Portland cement supplies the matrix, is certainly questionable. Portland cement and sand alone, when properly mixed to- gether with a small quantity of water, in proportions that shall leave no voids, make a good artificial stone, without the addition of shellac. This is known as Portland stone, and is briefly described in paragraph 200. It is not protected by any patent. This stone, however, like the Frear, is comparatively expensive, in consequence of the large proportion of cement required to avoid porosity. The addition of. common or hydraulic lime, under such conditions as shall, as far as our present knowledge extends, secure the best results, produces beton Ccignet. The durability of gum shellac, when exposed to the weather> is by no means certain. It readily yields to the solvent action THE AMERICAN BUILDING BLOCK. 87 of alkalies, and should be employed with caution in localities exposed to such influences. TBE AMERICAN BUILDING BLOCK COMPANY'S ARTIFICIAL HTONE. (the foster and van dekbukgh patent.) 168. Foster's process consists in mixing together slaked lime and moist silicious sand, and then subjecting the mixture to great pressure in moulds, the moulded blocks being left to harden in the open air. Very little water is used, and the quantity of lime should not exceed what is required to coat each and every grain of sand, and fill up the voids in the compacted mass. The cementing material in this stone is principally silicate of lime, slowly developed upon the surface of each grain of sand in contact with the lime, aided to some extent by the induration of hydrate of lime, and the formation of the double hydrate and carbonate of lime upon the surface of the block, and to the depth penetrated by the air. The formation of the silicate of lime is very greatly facilitated by the pressure to which the material is subjected, which diminishes the volume of voids, and the thickness of the lime coating, and renders the contact of the sand and lime more intimate. All the lime should be exhausted in coating the sand grains, to the end that it may td be converted into silicate. Any surplus remains more or less inert, and destitute of energy. 169. By Van Derhurgh's process, which is an improvement upon Foster's, ground quicJclime, instead of slaked lime, is mixed with the moist sand, thus utilizing the heat developed by slaking, before the mixture is moulded and pressed. Steam is also introduced into the loose mass to hasten the slaking, and the formation of the silicate of lime, 170. Professor Horsford, late of Harvard College, Cambridge, Mass., in his report upon the patents under which the improved process claims protection, says : " Van Derburgh, by his process, as at present carried out in " practical working, intimately mixes ^neZy grround! unslaked lime " with moist sand, in a close chamber, kept in constant agi- " tation. The afiinity of the unslaked lime for water causes the • " lime dust to adhere wherever it touches the surface of the " moist sand. Slaking instantly commences, and is aided by the 88 THE AMERICAN BUILDING BLOCKS. " introduction of steam into this confined space. Under these " circumstances, the heat involved in slaking the lime, as well as " the heat due to the steam admitted to the interior of the con- " tinuously stirred and kneaded mixture, is brought to bear on " the silica, at the surface of the sand grains, in contact with the "moist hydrate of lime. After continuing in this condition for " a suitable time, it is subjected to great pressure, imparted by " successive percussions in metallic moulds. The pressure re- " suits in a block, the surface of which rapidly becomes hard, " and the hardness gradually extends from the surface toward " the heart of the mass." 171. Professor Horsford analyzed samples of the Foster artificial building stone of various ages, the oldest of which has been for eleven years in a foundation wall. "This sample was nearly as hard as Connecticut sandstone,'' and was the only one in which all the lime was found " combined and rendered substantially insoluble." Others, only a few months old, were found equally hard at the surface, in consequence, doubtless, of the formation of the carbonate as well as the silicate of lime, but they were less firm in the interior. " A fresh fracture of a block several years old, shows a zone of peculiar shade, extend- ing from the outer surface toward the heart of the stone," marking the progress of certain chemical changes which accom- pany the indurating process, and illustrating its slow improve- ment by age. There is also a slow increase in the weight of the stone. 172. The Van Derburgh stone hardens more rapidly than Fos- ter's, for the simple reason that when silica and quick-lime are brought together in the presence of moisture, heat is evolved, which in this case is increased and maintained by the introduction of steam, and it is well known that the formation of the silicate of lime is facilitated by heat. Moreover, the powder of quick-lime slaking in contact with the moist sand, as in the Van Derburgh process, becomes more homogeneously and uniformly dis- tributed as a coating to the sand grains than it could be in the Foster process by mechanical means alone, after having been rendered in a certain sense inert by previous slaking. Hence the Van Derburgh artificial stone has generally been found to be superior in strength, hardness, and homogeneity to stone of the same age made after the Foster patent. 173. Both processes are, however, susceptible of very great im- provement in so far as they prescribe that the mixed materials THE AMERICAN BUILDING BLOCKS. 89 sliall be compacted in the moulds by pressure, instead of by the superior method of tamping or ramming, as practised in making beton Coignet, and by the Union Stone Company, ope- rating under the Sorel patent ; for although Van Derburgh introduced tamping into his practice, it is not understood that he claims the right under his patents to employ that method of compacting the mixed materials. The tardy induration of the Van Derburgh and Foster stone, arid indeed of all artificial stone into which common lime enters as the only, or the principal source of the matrix or cementing medium, places them under great disadvantage when in com- petition with a stone having an energetic hydrauUc lime or cement as its basis. 174. The Van Derburgh building blocks were used in the con- struction of the Howard University and Hospital buildings at Washington, District of Columbia, in 1868-69. The blocks were of a uniform size, being ten inches long, five inches wide, and four inches deep, and weighed about eleven pounds each. They had a vertical air-chamber through the centre six inches long and one inch wide. 175. A portion of the building fell down during the progress of construction, a circumstance which led to a careful examination of this artificial stone by experts appointed for that purpose. From the report of their trials furnished me by General 0. O. Howard, the information contained in the following table has been condensed. It g ves the crushing strength of the Van Derburgh building blocks taken from the Howard University Building and elsewhere. The trials were made under the super- intendence of Engineer Major W. E. King, U. S. Navy, at the Washington Navy Yard, D, C, in February, 1869. 90 THE AMEKICAN BUILDING BLOCKS. r-(CO>nOOCOO^O>0000'J< rH ^ CO tH CO CO oooooooooooooooooeo oooooooooOoocooooo>o 00 C5 O O !>• o O O (M lO CO C5 O CO r-l (>4 1-1 iH r-l 1-1 7-1 r-i -3 2'=£'iHoa5Qoi>-oio-*co r— " « i-i. o o o o o o o o o o o o O »0 05 O I— W o~ to" T-T i^" T-T tH tM (N CO !5 "d .iT' o o (N ^ ^ o o 2 c5 55 ^ ^ THE SOEEL ARTIFICIAL STONE. 93 PRACTICAL RESULTS. 178. " First. It was found that the plaster beds gave an in- " crease over previous tests, of 18,767^ pounds per block. " Second. The average of the five blocks was more than ten " times the amount required at the bottom of the "University "walls (3,000 pounds), and nearly sixteen times the amount re- " quired at the bottom of the Hospital walls (2,000 pounds). " Third. The average of the two Hospital blocks was 35,500 "pounds, or about eighteen times the actual pressure of the " building." REMARKS. 179. First. Size of blocks 10" long, 5" wide, 4" deep. Area under compression, omitting air-chamber, 44 square inches. Second. The weakest block crushed at 7,600 pounds (4 months old). The strongest block crushed at 64,000 pounds (10 years old). Average crushing strength of all the blocks, 24,231 pounds- Average crushing strength of blocks known to be between one and two years old, 17,953 pounds. Third. By dividing the total crushing strength of block by the area in square inches on the top surface, we get what it is customary to call the crushing strength per square inch, although the results thus obtained exceed the crushing strength of a one-inch cube of the material, and the larger the block is on the top the greater will this excess be, on account of the lateral support which the central portion of the block receives from the material surrounding it. Making the reduction in this manner, however, as was done for the other tables in the work, the following results are obtained : Crushing strength per square inch of weakest block, 173 pounds. Crushing strength per square inch of strongest block, 1,455 pounds. Average crushing strength per square inch of the twenty-one blocks, 551 pounds. THE UNION STONE COMPANY, BOSTON. 180. The Sorel Process. — It was stated in the Report on Beton Agglomere, paragraph 15, that " as a rule all hydraulic cements produced at a low heat, whether derived from argillaceous or argillo-magnesian limestones, are light in weight and quick set- ting," and are inferior for mortar or beton, to Portland cement or good hydraulic lime. The argillaceous and argillo-magnesian limestones here referred to, belong to that class which furnish 94 THE SOREL ARTIFICIAL STONE. cements in virtue of the compounds of lime formed in the kiln, as indicated in paragraph 17. These compounds are not formed until after carbonate of lime is reduced to quick-lime. The ce- ment derived from magnesite, at a low heat, does not come within the class above named, as the stone is neither argillaceous nor argillo-magnesian. 181. The hydraulic properties, when properly burnt, of many of the varieties of dolomitic limestones, became theoretically known many years ago, but the utilization of this knowledge, so as to render it of practical value in the builder's art, is of quite recent date. Carbonate of magnesia parts with its carbonic acid, and is converted into oxide of magnesium, at a temperature of from 300° to 400° Centigrade, or below that which produces a dark cherry red. The production of lime, or oxide of calcium, requires a heat of greater intensity. It is practicable to burn a magnesium limestone so as to convert the carbonate of magnesia into oxide of magnesium, while the bulk of the Ume remains a carbonate. 182. A paste made from dolomite, calcined below a cherry red heat and then reduced to powder by grinding, forms under water an artificial stone of considerable hardness. If the heat, however, be sufficiently intense to reduce the carbonate of lime also — say above 400° Centigrade — thus forming quick-lime, the addition of water causes slaking, and the hydraulic energy is destroyed or impaired by the presence of hydrate of lime. 183. Any magnesian limestone containing as high as 60 per cent, of carbonate of magnesia, may be presumed to be capable of yielding a good hydraulic cement if properly burnt. In the process of burning, however, great care is required. The temperature must be increased slowly to a dark cherry red heat, and maintained there until the carbonic acid is expelled from the magnesia. The lime remains in the form of carbonate. The burnt product must then be reduced to an impalpable powder, in order to fully develop its hydraulic energy. Magnesia obtained by calcining the chloride below a red heat, also exhibits remarkable hydraulicity, while the product result- ing from a white heat is nearly destitute of this property. 184. M. Sorel's Discovery. — M. Sorel, an eminent French chemist, discovered the oxychloride of magnesium to be a hy- draulic cement of great strength and hardness. This cement is the basis of the artificial stone manufactured by the "Union Stone Company," and is produced or formed by adding a solu- THE SOEEL ARTIFICIAL STONE. 95 tion of cMoride of magnesium, of the proper strength and in the proper proportions, to the oxide of magnesium obtained by cal- cining cai'bonate of magnesia, or magnesite. 185. The several steps in the process, beginning with the raw magnesite, are briefly as follows, viz. : — First. — The magnesite is burnt in ordinary lime-kilns, at a dark cherry red heat, for about 24 hours. The result is protoxide of magnesium, which is next ground to fine powder between hori- zontal mill-stones, furnishing what the Union Stone Company style, " Union Cement." Magnesite has been procured from various localities. That from Greece, California, Maryland, and Pennsylvania, contains about 95 per cent, of carbonate of magnesia, the residue being mostly insoluble silicious matter. The burnt product is perfectly white. A magnesite is procured in Canada, which contains from 60 to 85 per cent, of cai'bonate of magnesia. A variable per- centage of iron in the residue, gives the cement derived from this stone a reddish tint. The reports of State Geological Surveys indicate that magnesite exists in numerous localities in the United States. Second. — For making stone, the burnt and ground magnesite (oxide of magnesium) is mixed dry in the proper proportion with the material to be united, that is, with powdered marble, quartz, emery, silicious sand, soapstone, or with whatever sub- stance forms the basis of the stone to be imitated or reproduced. The usual proportions are for emery-wheels 10 to 15 per cent- of oxide of magnesium, by weight, for building blocks such as sills, lintels, steps, &c., 6 to 10 per cent., and for common work for thick walls, less than 5 per cent. The dry ingredients are mixed together by hand or in a mill. A hollow cylinder revolving slowly about its axis would answer the purpose. Third. — After this mixing they are moistened with chloride of magnesium, for which bittern water — the usual refuse of sea- side salt works — is a cheap and suitable substitute. The moist- ened material is then passed through a mill, which subjects it to a kind of trituration, by which each grain of sand, or other solid material, becomes entirely coated over with a thin film of the cement, formed by a combination of the chloride with the oxide of magnesium. The bittern water is required to be of the density of from 15"^ to 30° Baume. The mass on emerging from the 96 THE SOREL ARTIFICIAL STONE. mill should be about as moist as moulder's clay. The mixing machine used by the " Union Stone Company," is an improved pug mill invented by Mr. Josiah S. Elliott. It is represented as an excellent mill, doing its work thoroughly. Fourth. — The mixture is formed into blocks by ramming or tamping it in strong moulds of the required form, made of iron, wood, or plaster, precisely as described in paragraph 24, Report on Beton Agglomere. 186. The block may be taken out of the mould at once, and nothing further need be done to it. The setting is progressive and simultaneous throughout the mass, as with other hydraulic cements, and requires from one hour to one day, depending somewhat on the chemical properties of the solid ingredients used, the carbonates as a rule requiring a longer time than the silicates. Building blocks will bear handling, and may be used when three or four days old, although they do not attain their maxi- mum strength and hardness for several months. Emery wheels are not allowed to be used in less than four weeks. 187. This stone so closely resembles the natural stone, whether marble, soapstone, sandstone, &c., from which the solid ingre- dients are obtained by crushing and grinding, that it is difi&cult, without the application of chemical tests, to detect any difference in either texture, color, or general lithological ap- pearance. STRENGTH. 188. In strength and hardness, this stone greatly surpasses all other known artificial stones, and is equalled by few, if any, of the natural stones that are adapted to building purposes. The artificial marble takes a high degree of polish, being in this respect fully equal to the best Italian varieties. 189. Some trials of 2-inch cubes at the Boston Navy Yard gave the following results, reduced to the crushing pressure upon one square inch : No. 1, crushing strength per square inch, 7187^ lbs. No. 2, " " " llo62i " No. 3, " " " 21562^ " No. 4, »' " " 7343^ " In none of these samples did the proportion of the oxide of magnesium exceed 15 per cent, by weight of the inert material THE SOREL ARTIFICIAL STONE. 97 cemented together. This statement is derived from the Treasur- er of the Company. The principal business of the Union Stone Company up to the present time, has been the manufacture of emery wheels. The great tensile strength of the material may be inferred from the fact, that in the proof trials, the wheels are made to revolve with a velocity of from 2 to 3 miles per minute at the circumference. They do not usually begin to break until a velocity of from 4 to 5 miles per minute is attained. 191. From a nuinber of specimens of this stone furnished the writer by the Treasurer of the Company, who also gave their age and composition as reported below, comprising coarse and fine sandstone of various shades of color, hones, white and variegated marble, emery wheels, billiard balls, concrete building blocks, &c., some small blocks were prepared and subjected to crushing with the following results. 98 THE SOREL AETIFICIAL STONE. lO -s) cr> lO CO CO o CO CO CO !N 00 (M !M CD lO ^ O O c-T t-^ cT T-T o" t^" o o o o o o o o o o o X ^ X X X ^ =^ ^ '-^ ^ -7 X X X X X X rH t-l (N CO O (N lO (N THE SOREL ARTIFICIAL STONE. DURABILITY. 192. The proofs of the durability of the Union stone rests upon other evidence than that furnished by severe and prolonged climatic exposure. In Boston, however, building blocks have resisted two winters, and at the present time appear to be, and doubtless are harder and stronger than before they were touched with frost. Dr. C. T. Jackson, State Assayer of Massachusetts, reports iTpon it as follows : " I find that the frost test (saturated solution of sulphate of " soda) has not the power of disintegrating it in the least. The "trial was made by daily immersions of thefctone in the sulphate " of soda solution for a week, and allowing the solution to pene- " trate the stone as much as possible and then to crystaUize. " From this test it is evident that your stone will withstand the " action of frost more perfectly than any sandstone or ordinary " building stone now in use. I see no reason why it will not " stand as well as granite." 193. A perfect resistance to the freezing and thawing of one win- ter n:'ay safely be accepted as conclusive evidence of the durability in the open air, of an artificial stone of which the matrix is any kind of hydraulic cement. At no subsequent period will it be as Hkely to fail, from freezing and thawing, as during the first winter, 194. A stone suitable for all kinds of building purposes on land might, however, fail under the solvent action of sea water. On this head it can be said that magnesian compounds are under- stood to resist the immersion in the sea better than the com- pounds of alumina or lime. COST. 195. Assuming that the magnesite, in the undeveloped ledge, costs no more than a bed of hydraulic cement stone, and that the facilities for working the quarry are equal in the two cases, the oxide of magnesium could be manufactured as cheaply as hy- draulic cement. There will be a tendency to this equality in price, as new beds of magnesite are discovered and made available, and the demand for this new cement increases. The process of manufacture is the same in both cases, that is, the stone has to be quarried, burnt, and ground; with this advan- tage in favor of the magnesite, that a less intense heat, and con- 100 THE SOREL AETIFICIAL STONE. sequently less fuel, is needed for its proper calcination than hydraulic cement requires. 196. The " Union Stone Company" hav§ fixed the selling price of their ground oxide of magnesium at five cents per pound, which is eight times the wholesale market price of Rosendale cement in New York, and five times the price at which the best Portland cement may be imported by the cargo, inclusive of custom-house duties. The chloride of magnesium is another source of expense in the Sorel process; for although bittern water is a cheap substitute, and in the vicinity of sea-side salt works may be procured for little or nothing, its cost amounts to no inconsiderable item when it has to be transported to a distance. For these reasons, this new stone has, with some exceptions, been limited in its application to articles of small bulk and great comparative value, for which other approved and less expensive artificial stone is either not suitable, or of less practical value. Although for architectural ornaments of elaborate design it is perhaps less costly, even now, than granite or marble, it cannot hope to compete successfully for general adoption and use by engineers and architects, with the beton agglomere', and the softer kinds of natural stone, until the market price of the oxide of magnesium is greatly reduced. For the peculiar purposes to which it is adapted, it supplies what has heretofore been felt as a great want, and in this field, which is neither narrow nor un- varied, it has no prominent rival. This subject is discussed with discriminating judgment in a report from which I make the following extract : {Extract from the Report of the Committee of the Middlesex Agri. cultural Society, Hon. Simon Brown, Chairman.) " Union Stone Companys' Articles. — Building stones and " bricks ; soapstone sinks and tubs without joints ; tiles, curb- " stones, posts, emery wheels, grindstones, mantel pieces, &c., " &c. This stone work is a new enterprise, and in the opinion " of the Committee promises to become one of great general " utility. The Committee learn thjtt this Company has several " modes of manufacture, and have worked out and recorded more " than two thousand formulas, using in all cases the same cem- " entatious agent, magnesia, for which they have several Letters " Patent. The large stone upon which their goods were ex- " hibited, and upon which the spectators stood while examin- THE SOREL AETIFICIAL STONE. lOl " ing them, was made upon the spot, of magnesian cement, pre- " pared at the manufactory, and brought to the ground, where it "was mixed and moistened with the earth and gravel found " there ! The whole mixture was then pounded down, and in " the course of a week was transformed into stone as hard as " granite ! ! The manufactured article partakes of the nature " and color of the mineral substance used. That is, broken soap- " stone is used to make soapstone, marble to make marble. The " amount of cement (magnesia) used is so small a proportion of " the whole mass as to make no perceptible change in color or " quality. " The Committee were greatly interested in the articles pre- " sented by this Company — such as beautiful soapstone stoves, " whetstones, hones, medallions, with a surface as smooth as " polished ivory, emery wheels, and numerous other articles of " value. It does not seem improbale to the Committee that this ' device may be carried so far as to furnish coverings for build- "ings, tile, walls, outside chimneys, and even underpinning, " where stones cannot be had short of heavy cost of transporta- "tion." 197. The following formula has been found suitable for window- caps, sills, steps, &c. The quantities specified will make one cubic foot of stone. 100 pounds of beach sand, cost $1.00 per ton at the works 05 10 " " comminuted marble, cost $5.00 per ton at the works. . .02.^ 10 '• " Union cement (oxide of magnesium) 50 10 " " chloride of magnesium in solution, 20" Baume . ...... .02 130 pounds, yielding 1 cubic foot of moulded stone 59^ 198. The labor, depending somewhat on the design as regards the degree and character of its ornamentation, will vary per cubic foot, from 20 cents to 25 cents, making total cost of one cubic foot of finished building block 79| to 84| cents. This price may be reduced 10 to 15 cents per cubic foot by incorpo- rating large pebbles and small cobble stones during the process of moulding. For foundations and other plain, massive walls, the propor- tion of cement may be very considerably reduced, and the quan- tity of cobble stones increased. 199. The principal source of profit to the "Union Stone Com- pany" is doubtless the cement, of which they are presumed to have the monopoly. 102 COMPARISON OF STRENGTH AND COST. If magnesite shall be found to be so plenty, and so generally distributed over the country, that the market price of the ce- ment (oxide of magnesium) shall not greatly exceed that of Portland cement, which is now about $1.00 per 100 pounds in New York, this new artificial stone will not be more expensive than the common concrete made with American cement, while its remarkable strength, and the ease and certainty with which any desired shade of color can be attained, adapts the former to very many uses for which the latter is not suitable. PORTLAND STONE. 200. What is known under the name of Portland stone, is simply a mixture of Portland cement and sand, or both sand and gravel. It possesses, when properly made, the essentials of strength aud hardness, in an equal degree with beton Coignet, but is considerably more expensive, unless the cost is kept down by reducing the quantity of cement to that extent which renders the mixture weak and porous. Any of the methods of manipulation, by hand or machinery, described in the foregoing pages for beton Coignet, or for the Frear stone, will of course answer for Portland stone ; that is, the cement, sand, and gravel are first thoroughly mixed up together, with a sufficient quantity of water to make a damp incoherent mass, and then rammed into the moulds for building blocks, or formed as monoliths. There are no patents protecting the use of Portland cement in this way. On the contrary, it seems questionable whether the manufacture of Portland stone by the method that shall produce the best results, that is, by using the smallest quantity of water that will suffice, is not more or less an infringement of some of the Coignet patents. GENERAL COMPARISON OF STRENGTH AND COST. 201. Strength. — Ai-ranged according to their crushing strength, the several kinds of artificial stone described in the foregoing pages, assume the following order, from the strongest to the weakest : 1. The Sorel stone (Union Stone Company, Boston, Mass). 2. Beton Agglomere or Coignet-Beton. 3. The Kansome Silicious Concrete stone. COMPAEISON OF STRENGTH AND COST. 103 4. The Frear stone. 5. The Portland stone. 6. The Foster and Van Derburgh stone (American Building Block). The Sorel stone, in which the cement used is oxide of magne- sium, stands prominently in advance of all the other kinds of artificial stone, in strength and hardness. There is no marked difference between beton Coignet and Ransome's stone in crushing strength, nor again between the Frear and the Portland stone, assuming that the alkaline solu- tion of gum shellac used in making the Frear is stable and enduring, and does not in process of time deteriorate, under the effect of alkalies and ammonias introduced from without. 202. Cost. — If the several stones be arranged according to their estimated cost, for the same character and class of work, they will assume the following order, from the lowest to the highest : 1. The Foster and Van Derburgh stone. 2. Beton Agglomere. 3. The Portland stone. 4. The Frear stone. 5. The Ransome stone. 6. The Sorel stone. There is but little difference in cost between the Frear and the Portland stone, and that is due to the use of shellac in the former. Omit this, and pursue the same method of mixing for both, and the two become identical in composition, strength, and cost. INDEX. The numbers refer to the paragraph. 8, 14, 16 Analyses of various cements ' 57,60,61,63 Arches in Beton Agulomere ' 168—197 American Building Block Company's Stone 21, 2o Artificial stone paste Alumina in mortars Barracks at Notre Dame, Paris Balcony Falls cement : Analysis of ^ Beton agglomere : How made •' ' ^ Matrix of Materials for 3, 4, 5, 6, 7, 8, 9, 10 „ , „ 4, 20 Sand for ' 5 Common lime for Hydraulic lime for 6, 7, 8, 9 Hydraulic cement for Fabrication of ^^'■^^ 24 Agglomeration of 23 Moulds for. Machinery for making. Color of 24 29-35 Crushing strength of 50, 52, 53 Tests of arches made of Properties of ^2-56 Use; of 57-69 Cost of '^0' ^1 Various qualities of '^•^ Tensile strength of ^'^ Strength of : increased by age 76-78 Materials not suitable for 15, 16, 97 2 74 Beton, common ' Brick : Crushing strength of "^^ Cement : Portland Where made Tests for ^^"^^ Analysis of . Manufacture of 100-116 Chalk : Crushing strength of . COPLAY cement Concrete 54 : Not suitable for beton agglomere 15, 97 2,56 Color of bkton agglomere ' ^"^ Constructions on Land 57-64 In the sea Comparisons of tensile strength 37-45 Curves op tensile strength (Plate I. ) Crushing strength : Of various mixtures 49, 50 Of American Building Blocks 175-179 Of beton agglomere 50, 52, 53 106 INDEX. Crushing strength : Of Frear stone 165-167 Of mortar 50 Of Sorel stone made by Union Stone Company 188191 Of cement, sand and gravel 51 Of bricks; of chalk; of granite ; of limestone; of sandstone 54 CrarBERLAND CEJiEXT : Not Suitable for beton agglomi're 15, 16, 97 CnuRCH AT Vesixet 59 English tests for Portland cement 11 Emery WHEELS , 190 Exposition building (Paris) 61 French tests for Portland cements 12 Frear Stone 161-164 Foster's Patent 168-173 Granite : Crushing strength of 54 Gravel : Crushing strength of, with cement and sand 51 Tensile strength of, with cement and sand 46 May replace sand in betons 46, 51 Weight of 36 German Portland cement : Tensile strength of 46 German test for Portland cement 13 Greyveldinger mortar mill (Plate III. ) 32 General deductions 76-96 Grindstonbs, Ransomr's patent 151 152 Hydraulic lime 6 Analysis of 8 How manufactured 98-112 Hardening of mortar: Theory of 17 Hardening process of Ransome 155-160 Hollow walls 28, 64 Houses (Plate VH.) 63 Hoffmann's annular kiln 123-131 Howard University 174-179 Jetties at Port Said 65 Kilns for burning cement (Plate IX.) 117-124 Lime, common and hydraulic 5-9 "With cement and sand 45 Mortars and betons weakened by addition of common 45, 47, 48 Limestone : crushing strength of 54 Light-house at Port Said 5S Louisville cement 15, 45, 97 Machines and Implements for making beton agglomere 29-35 Magnesite 184, 185 Magnesian limestone: Hydraulic properties of 180-183 Malaxator 33 Matrix ig Mortar : Definition of 1 Volume of matrix of. 1, 2 Induration of 17 Magnesia in -17 Mills for mixing 31 32 33 Tensile strength of 40 Crushing strength of 50 Moulds 24 Monolithic masonry 24, 26 27, 28 Under water 56, 65 Ornamentation 26 Portland cement; 10 Weight of 10, 11, 12, 13, 36, 37 Tensile strength of 37, 38, 39, 40, 45, 46, 48 Crushing strength of 49, 50 INDEX. 107 Portland cement : Weakened by addition of lime 45, 47, 48 How manufactured by wet process 114 " " " dry process 115 Burning 117-124 Cost of, in Germany 129 Cost of, in the United States 130 Portland stone 200 Porosity 47, 72 Phooess for hardening stone, Ransome's 155-160 Proportions: Of materials for beton agglomere 22 Of materials for common beton 73, 74, 74a PoG Mill 31 Rammers 34 Ransome's patent stone 132-134 Rosendale cement : Variable quality of 42 Analysis of 16 Weight of 36 Tensile strength of 38, 41, 43, 45 Crushing strength of , 50, 51 Not suitable for beton agglomere 15, 97 Sand: Weight of 36 Sandstone : Crushing strength of 54 Seilley Lime : Weight of ■. 36 Sewers 62 Silica in mortars , 17 SoREL process 180-185 Sustaining walls (Plate VIII.) 64 Tensile Strength : Curves of, (Plate I.) Of Portland Cement 37, 38, 39 Of Rosendale cement 38, 41, 43, 45 Of Portland and Rosendale cements, mixed 38, 40 Of Portland cement and sand 39, 40, 45, 46 Of Rosendale cement and sand , 41, 45 Of Portland cement, sand and lime 45, 74ct Of Louisville cement; Bondurant and Ford 45 Of Coplay cement 45 Of German Portland cement 46 Of beton agglomere 40 Of mortar 40 Of cement, sand and gravel 46 Theil hydraulic lime 7) 8, 9 Weight of 36 Analysis of 8 Trituration 3, 5, 21, 73 Union Stone Commpany's stone 180-189 Vassy Cement : Analysis of 16 Vanne Aqueduct (Plates IV., V., VI) 57 Van Derburoii's patent 168-173 Weights : Of Theil hydraulic lime 9, 36 Of Portland cement 36 Of Rosendale cement 36 Of Seilley lime 36 Of gravel.... 36 Of sand 36 Of common lime 36 Pl.l DIAGRAM SHOWING THE TENSILE STRENGTH PER SQUARE INCH OF PORTLAND CEMENT. WITH AND WITHOUT SAND, AT VARIOUS AGES. Nat HouhMfm' PorUand Cement 10/ Lbs. per bushel, mthout sand.. LEGEND . Z . J „ , 5 UrufUsti , 6 /09 / wl. cement 2 vol.gniu^ . 1 „ . 4 „ / . . 10 n nithout sand / vol cement / vol Thames sand. No 7 ^ English Portland (hment WO Lbs per bushel , / vol cement, Z vol. Thames sand . S_ „ • -M- M- » » ^ +*+ +M- / n 3 , i „ ,. d „ trithottt sand. i vol. cement / vol. sand rnti)tffi-'>' vidtfJhs iHokfhs nw^iUis numths m^Mus rndfiffw TriJnths nio^fJis ninths It 2p 2i 2)^ ,ths ninths nU^^ „J^i/„- ,„t\,ths muktils ma^ „wUhs nwkths mXtlis Back of Foldout Not Imaged Back of Foldout Not Imaged Back of Foldout Not Imaged Back of Foldout Not Imaged Back of Foldout Not Imaged THE VANNE AQUEDTJCT, PRANCE. Back of Foldout Not Imaged PI. vn CELLAR IN "BETON ACCLOMERE' RUE DE PARIS N?36 PARIS Back of Foldout Not Imaged PI. VIII SUSTAINING WALL OF THE CEMETERV AT PAS SY , NEAR PARIS, FRANCE. IN "BETON AGGLOMERE*. Se^otion on LLney C. D. F. G . P. Q . Senile : / ///^A - 10 fe^t. Back of Foldout Not Imaged SCIENTIFIC BOOKS PUBLISHED BY D. Yan NoSTEAND, 23 Murray Street & 27 Warren Street, NEW YORK. Weisbach's Mechanics. H'ew and Revised Edition. 8yo. Cloth. $10.00. A MANUAL OF THE MECHANICS OF ENGINEERING, and of the Construction of Machines. By Julius Weisbach, Ph. D. Translated from the fourth augmented and improved Ger- man edition, by Eckley B. Coxe, A.M., Mining Engineer. Vol. I.— Theoretical Mechanics. 1,100 pages, and 902 wood-cut illustrations. Abstract of Contents.— Introduction to the Calculus— The General Principles of Mechanics— Phoronomics, or the Purely Mathematical Theory of Motion— Mechanics, or the General Physical Theory of Motion - Statics of Rigid Bodies— The Application of Statics to Elasticity and Strength— Dynam- ics of Eigid Bodies -Statics of Fluids -Dynamics of Pluids— The Theary of Oscillation, etc. " The present edition is an entirely new work, greatly extended and very much improved. 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Third edition, revised and enlarged, including many New Ex- periments on Gauging Water in Open Canals, and on the Flow through Submerged Orifices and Diverging Tubes. With 23 copperplates, beautifully engraved, and about 100 new pages of text. The -work ia divided into parts. Part I., on hydraulic motors, includes ninety-two experiments on aa improved Foumeyron Turbine Water-Wheel, of about two hundred horse-power, with rules and tables for the construction ' of similar motors ; thirteen experiments on a model of a centre-vent water- wheel of the most simple design, and thirty-nine experiments on a centre-vent water-wheel of about two hundred and thirty horse-power. 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In 1855 the proprietors of the Locks and Canals on Merrimack River con- sented to the publication of the first edition of this work, which contained a selection of the most important hydraulic experiments made at Lowell up to that time. In this edition the principal hydraulic experiments made there, subsequent to 1855, have been added, including the important series above mentioned, for determining rules for the gauging the flow of water in open canals, and the interesting series on the flow through a submerged Venturi's tube, in which a larger flow was obtained than any we find recorded. D. VAN NOSTRAND. 3 Francis on Cast-Iron Pillars. 8vo. aoth. $2.00. ON THE STRENGTH OF CAST-IRON PILLARS, with Tables for the use of Engineers, Architects, and Builders. By James B. Francis, Civil Engineer. Merrill's Iron Truss Bridges. Second Edition. 4to. Cletk. $5.00. IRON TRUSS BRIDGES FOR RAILROADS. The Method of Calculating Strains in Trusses, with a careful comparison of the most prominent Trusses, in reference to economy in combination, etc., etc. By Brevet Colonel William E. Mesrill, U.S.A., Major Corps of Engineers. Nine lithographed plates of illustra- tions. " The work before us is an attempt to give a basis for sound reform in this feature of railroad engineering, by throwing 'additional light upon the method of calcul iting the maxima strains that can come upon any part of a j bridge truss, and upon the manner of proportioning each part, so that it shall be as strong relatively to its own strains as any other part, and so that the entire bridge may be strong enough to sustain several times as great strains as the greatest that can come upon it in actual use.' " — Scientific American. 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General Sections of Mississippi River ai Quin- cy, showing location of Bridge. III. General Sections of Mississippi River at Quincy, showing location of Bridge. IV. Plans of Masonry. V. Diag-ram of Spans, showing the Dimensions, Arrangement of Panels, etc. VI. Two hundred and fifty feet span, and de- tails. VII. Three hundred and sixty feet Pivot Draw. VIII. Details of three hundred and sixty feet Draw. IX. Ice- Breakers, Foundations of Piers and Abutments, Water Table, and Curve of Deflections. X. Founda- tions of Pier 2, in Process of Con- struction. XI. Foundations of Pier 3, and its Protection. XII. Founda- tions of Pier 3, in Process of Construc- tion, and Steam Dredge. XIII. Foun- dations of Piers 5 to 18, in Process of Construction. XIV. False Works, showing Process of Handling and Set- ting Stone. XV. False Works for Raising Iron Work of Superstructure. XVI. Steam Dredge used in Founda- tions 9 to 18. XVII. Single Bucket Dredge used in Foundations of Bay Piers. XVIII. Saws used for Cut- ting Piles under water. XfX. Sand Pump and Concrete Box. XX Ma- sonry Travelling Crane. Whipple on Bridge Building. 8vo, Illustrated. Cloth. $4.00. AN ELEMENTARY AND PRACTICAL TREATISE ON BRIDGE BUILDING. An enlarged and improved edition of the Author's original work. By S. Whipple, C. E., Inventor of the Whipple Bridges, &c. The design has been to develop from Fundamental Principles a system easy of comprehension, and such as to enable the attentive reader and student to j udge understandingly for himself, as to the relative merits of different plans and combinations, and to adopt for use such as may be most suitable for the cases he may have to deal with. It is hoped the work may prove an appropriate Text-Book upon the subject treated of, for the Engineering Student, and a useful manual for the Practic- ing Engineer and Bridge Builder. 6 SCIENTIFIC BOOKS PUBLISHED BY Stoney on Strains. New and Hevised Edition^ with numerous illustrations. Eoyal 8vo, 664 pp. Cloth. $15.00. THE THEORY OF STRAINS IN GIRDERS and Similar Struc- tures, with Observations on the AppUcation of Theory to Practice, and Tables of Strength and other Properties of Materials. By BiNDON B. Stonet, B. a. Roebling's Bridges. Imperial folio. Clotli. $25.00. LONG AND SHORT SPAN RAILWAY BRIDGES. By Johk A. RoEBLiNG, C. E. Illustrated with large copperplate engrav- ings of plans and views, ZAst of Mates 1. Parabolic Truss Railway Bridge. 2, 3, 4, 5, 6. Betaila of Parabolic Truss, -with centre span 500 feet in the clear. 7. Plan and View of a Bridge over the Mississippi River, at St, Liouis, for railway and common travel. 8, 9, 10, 11, 13. Details and View of St, Louis Bridge, 13, Railroad Bridge over the Ohio. Diedrichs' Theory of Strains. Svo. Cloth. $5.00. A Compendium for the Calculation and Construction of Bridges, Roofs, and Cranes, with the Application of Trigonometrical Notes, Containing the most comprehensive information in re- gard to the Resulting Strains for a permanent Load, as also for a combined (Permanent and Rolling) Load. In two sections adapted to the requirements of the present time. By John Die»- BIOHS, Illustrated by numerous plates and diagrams. *' The want of a compact, universal and popular treatise on the Conatruc- tion of Roofs and Bridgea—especially one treating of the influence of a varia- ble load^and the unsatisfactory essays of different authors on the subject, induced me to prepare this work." Z>. VAJ^r JSrOSTBAJ^J}. 7 Whilden's Strength of Materials. 12mo. Cloth. $2.00. ON THE STEENGTH OF MATERIALS used in Engineering Construction. By J. K. Whilden. Campin on Iron Roofs. Large 8vo. Cloth. $3.00. ON THE CONSTEUCTION OF lEON EOOFS. A Theoretical and Practical Treatise. By Feancis Campin. With, wood-cuts and plates of Eoofs lately executed. " The mathematical formulas are of an elementary kind, and the process admits of an easy extension so as to embrace the prominent varieties of iron truss bridges. The treatise, though of a practical scientific character, may be eaaily mastered by any one familiar "with elementary mechanics and plane trigonometry." Holley's Railway Practice. 1 vol. folio. Cloth. $12.00. AMEEICAN AND EUEOPEAN EAILWAY PEACTICE, in the Economical Generation of Steam, including the materials and construction of Coal-burning Boilers, Combustion, the Varia- ble Blast, Vaporization, Circulation^ Super-heating, Supplying and Heating Feed-water, &c., and the adaptation of Wood and Coke-burning Engines to Coal-burning ; and in Permanent Way, including Eoad-bed, Sleepers, Eails, Joint Fastenings, Street Eailways, &c., &c. By Alexandee L. Hollet, B. P. With 77 lithographed plates. " This is an elaborate treatise by one of our ablest civil engineers, on the con- struction and use of locomotives, with a few chapters on the building of Rail- rocvds. * * * AH these subjects are treated by the author, who is a first-class railroad engineer, in both an intelligent and intelligible manner. The facta and ideas are well arranged, and presented in a clear and simple style, accompanied by beautiful engravings, and we presume the work will be regard- ed as indispensable by all who are interested in a knowledge of the construc- tion of railroads and rolling stock, or the working of locomotives." — Scientific Americcm. 8 jS CIENTIFIC B 0 OKS P UB LI SHED B Y Henrici's Skeleton Structures. 8vo, Cloth. $3.00. SKELETON STEUCTUEES, especially in their Application to the building of Steel and Iron Bridges. By Olaus Henkici. With folding plates and diagrams. By presenting these general examinations on Skeleton Structures, with particular application for Suspended Bridges, to Engineers, I renture to ex- press the hope that they will receive these theoretical results with some confi- dence, even although an opportunity is wanting to compare them with practi- cal results. O. H. Useful Information for Railway Men. Pocket form. Motooco, gilt, $2.00. Compiled by W. G. Hamilton, Engineer. Eifth edition, revised and enlarged. 570 pages. *' It embodies many valuable formulse and recipes useful for railway men, and, indeed, for almost every class of persons in the world. The ' informa- tion ' comprises some valuable formulae and rules for the construction of boilers and engines, masonry, properties of steel and iron, and the strength of materials generally." — Railroad Gazette, Chicago. Brooklyn Water Works. 1 vol. folio. Cloth. $20.00. A DESCEIPTIVE ACCOUNT OE THE CONSTEUCTION OF THE WOEKS, and also Eeports on the Brooklyn, Haitford, Belleville, and Cambridge Pumping Engines. Prepared and printed by order of the Board of Water Commissioners. With 59 illustrations. Contents. — Supply Ponds — The Conduit— Ridgewood Engine House and Pump Well — Ridgewood Engines — Force Mains — E-idgewood Reservoir — Pipe Distribution — Mount Prospect Reservoir — Mount Prospect Engine House and Engine — Drainage G-rounds — Sewerage Works — Appendix. D. VAN' m STRAND. 9 Zirkwood on Filtration. 4to. Cloth. $15.00. EEPOET ON THE FILTRATION OF EIVER WATEES, for tlie Supply of Cities, as practised in Europe, made to the Board of Water Commissioners of the City of St. Louis. By James P. KiRKwooD. Illustrated by 30 double-plate engravings. Contents. — Report on Filtration — London "Works, General — Chelsea "Water Works and Filters — Lambeth "Water "Works and Filters — Southwark and "Vauxhall Water Works and Filters— Grand Junction Water Works and Filters — West Middlesex Water Works and Filters — ISTe-w River Water Works and Filters — East London Water Works and FUters — Leicester Water Works and Filters — York Water Works and Filters — Liverpool Water Works and Filters— Edinburgh Water Works and Filters — Dublin Water Works and Filters — Perth Water Works and Filtering Gallery — Berlin Water Works and Filters — Hamburg Water Works and Reservoirs — Altona Water Works and Filters — Tours Water Works and Filtering Canal — Angers Water Works and Filtering Galleries — Nantes Water Works and Filters — Lyons Water Works and Filtering Galleries — Toulouse Water Works and Filtering Galleries — Marseilles Water Works and Filters — Genoa Water Works and Filtering Galleries — Leghorn Water Works and Cisterns — Wakefield Water Works and Filters — Appendix. Tnnner on Roll-Turning. 1 vol. 8vo. and 1 vol. plates. $10.00. A TEEATISE ON EOLL-TUENINO FOE THE MANUFAC- TUEE OF lEON. By Peter Ttjnnek. Translated and adapted. By John B. Peaese, of the Pennsylvania Steel Works. With numerous wood-cuts, 8vo., together with a folio atlas of 10 litho- graphed plates of Eolls, Measurements, &c. " We commend this book as a clear, elaborate, and practical treatise upon the department of iron manufacturing operations to which it is devoted. The writer states in his preface, that for twenty-five years he has felt the necessity of such a work, and has evidently brought to its preparation the fruits of experience, a painstaking regard for accuracy of statement, and a desire to furnish information in a style readily understood. The book should be in the hands of every one interested, either in the general practice of mechanical engineering, or the special branch of manufacturing operations to which the work relates.'' — American Artisan. 10 SCIENTIFIC BOOKS PUBLISHED BT G-lynn on the Power of Water. 12nio. Cloth. $1.00. A TEEATISE ON THE POWER OF WATER, as applied to drive Flour Mills, and to give motion to Turbines and other Hydrostatic Engines. By Joseph Gltnn, F.R. S. Third edition, revised and enlarged, with numerous illustrations. Hewson on Embankments. 8vo. Cloth. $2.00. PRINCIPLES AND PRACTICE OF EMBANKING LANDS from Eiver Floods, as apphed to the Levees of the Mississippi. By WiLLiAK Hewson, Civil Engineer. " This is a valuable treatise on the principles and practice of embanking lands from river floods, as applied to the Levees of the Mississippi, by a highly intelUgent and experienced engineer. The author says it is a first attempt to reduce to order and to rule the design, execution, and measurement of the Levees of the Mississippi. It is a most useful and needed contribution to scientific literature. — Philadelphia Evening Journal. G-runer on Steel. 8vo. Cloth. $3.50. THE MANUFACTURE OF STEEL. By M. L. Geth^r, trans- lated from the French. By Lenox Smith, A. M., E. M., with an appendix on the Bessemer Process in the United States, by the translator. Illustrated by lithographed drawings and wood-cuts. " The purpose of the -work is to present a careful, elaborate, and at the same time practical examination into the physical properties of steel, as well as a description of the new processes and mechanical appliances for its manufac- ture. The information which it contains, gathered from many trustworthy sources, will be found of much value to the American steel manufacturer, who may thus acquaint himself with the results of careful and elaborate ex- periments in other countries, and better prepare himself for successful com- petition in this important industry with foreign makers. The fact that this volume is from the pen of one of the ablest metallurgists of the present day, cannot fail, we think, to secure for it a favorable consideration.— /roTi Age. D. VAN' NOSTMAJSTD. 11 Banerman on Iron. 12mo. Cloth. $2.00. TREATISE ON THE METALLURGY OF IRON. Contain- ing outlines of the History of Iron Manufacture, methods of Assay, and analysis of Iron Ores, processes of manufacture of Iron and Steel, etc., etc. By H. Baueeman. Eirst American edition. Revised and enlarged, with an appendix on the Martin Process for making Steel, from the report of Abram S. Hewitt. Illustrated with numerous wood engravings. " This is an important addition to the stock of technical works published in this country. It embodies the latest facts, discoveries, and processes con- nected with the manufacture of iron and steel, and should be in the hands of every person interested in the subject, as well as in all technical and scientific libraries."— /Scjenii/itf American. Link and Yalve Motions, by W. S. Auchincloss. 8vo. Cloth. $3.00. APPLICATION OF THE SLIDE YALYE and Link Motion to Stationary, Portable, Locomotive and Marine Engines, with new and simple methods for proportioning the parts. By William S. Auchincloss, Civil and Mechanical Engineer. Designed as a hand-book for Mechanical Engineers, Master Mechanics, Draughtsmen and Students of Steam Engineering. All dimen- sions of the valve are found with the greatest ease by means of a Printed Scale, and proportions of the link determined without the assistance of a model. Illustrated by 37 wood-cuts and 21 lithographic plates, together with a copperplate engraving of the Travel Scale. All the matters we have mentioned are treated with a clearness and absence of unnecessary verbiage which readers the work a peculiarly valuable one. The Travel Scale only requires to be known to be appreciated. Mr. A. writes so ably on, his aubject, we wish he had written more, London En" gineering. We have never opened a work relating to steam which seemed to us better calculated to give an intelligent mind a clear understanding of the depart- ment it discusses. — Scientific American. 12 SCIENTIFIC BOOKS PUBLISHED BY Slide Valve by Eccentrics, by Prof. C. W. MacCord. 4to. Illustrated. Cloth, |4.00. A PEACTICAL TEEATISE ON THE SLIDE VALVE BY ECCENTRICS, examining by methods, the action of the Eccen- \ trie upon the Slide Valve, and explaining the practical proces- ses of laying out the movements, adapting the valve for its various duties in the steam-engine. For the use of Engineers, Draughtsmen, Machinists, and Students of valve motions in general. By C. W. MacCori), A. M., Professor of Mechanical Drawing, Stevens' Institute of Technology, Hoboken, N J. Stillman's Steam-Engine Indicator. 12mo. Clotli. $1.00. THE STEAM-ENGINE INDICATOR, and the Improved Mano- meter Steam and Vacuum Gauges ; their utility and application By Paxil Stillman. New edition. Bacon's Steam-Engine Indicator. 12mo. Clotli. $1.00. Mor. $1.50. A TEEATISE ON THE EICHAEDS STEAM-ENGINE IN- DICATOR, with directions for its use. By Chaeles T. Portee. Revised, with notes and large additions as developed by Amer- ican Practice, with an Appendix containing useful formulae and rules for Engineers. By F. W. Bacon, M. E., Member of the American Society of Civil Engineers. Illustrated. In this work, Mr. Porter's book has been taken as the basis, but Mr. Bacon has adapted it to American Practice, and has conferred a great boon on American Engineers. — Artifian. Bartol on Marine Boilers. 8vo. Cloth. $1.50. TEEATISE ON THE MARINE BOILERS OF THE UNITED STATES. By H. B. Baetol. Illustrated. D. VAN NOSTRANB. 13 G-illmore's Limes and Cements. Fourth Edition. Revise'! and Enlargd. 8vo. Cloth. $4.00. PEACTIOAL TEEATISE ON LIMES, HYDEAULIO CE- MENTS, AND MOETAES. Papers on Practical Engineering, U. S. Engineer Department, No. 9, containing Eeports of numerous experiments conducted in New York City, during the years 1858 to 1861, inclusive. By Q,. A. Gillmoke, Brig-General U. S. Volunteers, and Major U. S. Corps of Engineers. Witli numerous illustrations. " This work contains a record of certain experiments and researches made under the authority of the Engineer Bureau of the "War Department from 1858 to 1861, upon the various hydraulic cements of the United States, and the materials for their manufacture. The experiments were carefully made, and are well reported and compiled. ' — Journal Franklin Institute. Grillmore's Coignet Beton. 8vo. Cloth. $2.50. COIGNET BETON AND OTHEE AETIFICIAL STONE. By U. A. GiLLMOEE. 9 Plates, Views, etc. This work describes with considerable minuteness of detail the several kinds of artificial stone in most general use in Europe and now beginning to be introduced in the United States, discusses their properties, relative merits, and cost, and describes the materials of which they are composed The subject is one of special and growing' interest, and we commend the work, embodying aa it does the matured opinions of an experienced engineer and expert. * Williamson's Practical Tables. 4to. Flexible Cloth. $2.50. PEACTICAL TABLES IN METEOEOLOGY AND HYPSO- METEY, in connection with the use of the Barometer. By Col, E. 8. WllLIAMSOM, U. S. A. \ 14 SCIEJSTTIFIC BOOKS PUBLISHED BY Williamson on the Barometer. 4to. Cloth. $15.00. ON THE USE OF THE BAROMETER ON SURVEYS AND RECONNAISSANCES. Part I. Meteorology in its Connec- tion with. Hypsometry. Part II. Barometric Hypsometry. By R. S. Willi AMsoi^, Bvt. Lieut. -Col. U. S. A., Major Corps of Engineers. With Illustrative Tables and Engravings. Paper No. 15, Professional Papers, Coi-ps of Engineers. " San Francisco, Cal., Feb. 27, 1867. " Gen. A. A. Humphreys, Chief of Engineers, U. S. Army : " General, — I have the honor to submit to you, in the follo-wing pages, the results of my investigations in meteorology and hypsometry, made with the view of ascertaining how far the barometer can be used as a reliable instru- ment for determining altitudes on extended lines of survey and reconnais- sances. These investigations have occupied the leisure permitted me from my professional duties during the last ten years, and I hope the results Avill be deemed of suiScient value to have a place assigned them among the printed professional papers of the United States Corps of Engineers. " Very respectfully, your obedient servant, "R. S. WILLIAMSON, "Bvt. Lt.-Col. U. S. A., Major Corps of U. S. Engineers." Yon Cotta's Ore Deposits. 8vo. Cloth. $4.00, TREATISE ON ORE DEPOSITS. By Beknhard Von Cotta, Professor of Geology in the Royal School of Mines, Freidberg, Saxony. Translated from the second German edition, by Frederick Prime, Jr., Mining Engineer, and revised by the author, with numerous illustrations. " Prof. Von Cotta of the Ereiberg School of Mines, is the author of the best modern treatise on ore deposits, and we are heartily glad that this ad- mirable work has been translated and published in this country. The trans- lator, Mr. Erederick Prime, Jr., a graduate of Freiberg, has had in his work the great advantage of a revision by the author himself, who declares in a prefatory note that this may be considered as a new edition (the third) of his own book. " It is a timely and welcome contribution to the litera,ture of mining in this country, and we aro grateful to the translator for his enterprise and good judgment in undertaking its preparation ; while we recognize with equal cor- diality the liberality of the author in granting both permission and assist- ance." — Extract from Review in Engineering and Mining Journal. D. VAN JSrO STRAND. 15 Plattner's Blow-Pipe Analysis. Second edition. Eevised. 8vo. Cloth. $7.50. PLATTNER'S MANUAL OF. QUALITATIVE AND QUAN- TITATIVE ANALYSIS WITH THE BLOW-PIPE. Prom the last German edition Eevised and enlarged. By Prof. Th. EicHTExi, of the Royal Saxon Mining Academy. Translated by Prof. H. B. Cornwall, Assistant in the Columbia School of Mines, New York ; assisted by John H. Caswell. Illustrated with eighty-seven wood-cuts and one Lithographic Plate. 560 pages. " Plattner's celebrated -work has long been recognized as the only complete book on Blow-Pipe Analysis. The fourth German edition, edited by Prof. Eichter, fully sustains the reputation which the earlier editions acquired dur- ing the lifetime of the author, and it is a source of great satisfaction to us to know that Prof. Eichter has co-operated with the translator in issuing the American edition of the work, which is in fact a fifth edition of the original work, being far more complete than the last German edition."— /SiZ^tmaTi'a Journal. There is nothing so complete to be found in the English language. Platt- ner's book is not a mere pocket edition ; it is iatended as a comprehensive guide to all that is at present known on the blow-pipe, and as such is really indis- pensable to teachers and advanced pupils. " Mr. Cornwall's edition is something more than a translation, as it contains many corrections, emendations and additions not to be found in the original. It is a decided improvement on the work in ita German dress."— Jimrna^ of Applied Chemistry. Egleston's Mineralogy. 8vo. Illustrated with 34 Lithographic Plates. Cloth. $4.50. LECTURES ON DESCRIPTIVE MINERALOGY, Delivered at the School of Mines, Columbia College. Br Pkofessor T. Egleston. These lectures are what their title indicates, the lectures on Mineralogy, delivered at the School of Mines of Columbia College. They have been printed for the students, in order that more time might be given to the vari- ous methods of examining and determining minerals. The second part has only been printed. The first part, comprising crystallography and physical mineralogy, will be printed at some future time. 16 SCIENTIFIC BOOKS PUBLISHED BY Pynchon's Chemical Physics. New Edition. Revised and Enlarged. Crown 8vo. Clotli. $3.00. INTEODUCTION TO CHEMICAL PHYSIOS, Designed for the Use of Academies, Colleges, and High Schools. Illustrated with numerous engravings, and containing copious experiments with directions for preparing them. By Thomas Euggles Pynchon, M. A., Professor of Chemistry and the Natural Sciences, Trinity College, Hartford. Hitherto, no -work suitable for general use, treating of all these subjects within the limits of a single volume, could be found ; consequently the atten- tion they have received has not been at all proportionate to their importance. It is believed that a book containing so much valuable information within so small a compass, cannot fail to meet with a ready sale among all intelligent persons, while Professional men, Physicians, Medical Students, Photograph- ers, Telegraphers, Engineers, and Artisans generally, will find it specially valuable, if not nearly indispensable, as a book of reference. " We strongly recommend this able treatise to our readers as the first work ever published on the subject free from perplexing technicalities. In style it is pure, in description graphic, and its typographical appearance is artistic. It is altogether a most excellent work." — Edeciic Medical Journal. " It treats fully of Photography, Telegraphy, Steam Engines, and the various applications of Electricity, In short, it is a carefully prepared volume, abreast with the latest scientific discoveries and inventions."' — Hart- ford Courant. Plympton's Blow-Pipe Analysis. 12mo. Cloth. $2.00. THE BLOW-PIPE : A System of Instruction in its practical use being a graduated course of Analysis for the use of students, and all those engaged in the Examination of Metallic Combina- tions. Second edition, with an appendix and a copious index. By Geoege W. Plympton, of the Polytechnic Institute, Brooklyn. " This manual probably has no superior in the English language as a text- book for beginners, or as a guide to the student working without a teacher. To the latter many illustrations of the utensils and apparatus required in using the blow-pipe, as well as the fully illustrated description of the blow- pipe flame, will be especially serviceable." — New York Teacher. D. VAN' N08TRAND. 17 lire's Dictionary. Sixth Edition, London, 1873. 3 vols. 8vo. Cloth, $25.00. Half Russia, $37.50. DICTIONAEY OP AETS, MANUFACTUEES, AND MINES. By Andeew Uee, M.D. Sixth edition. Edited by Eobeet Hunt, F.E.S., greatly enlarged and rewritten. Brande and Cox's Dictionary, New Edition. London, 1872. 3 vols. 8vo. Cloth, $20.00. Half Morocco, $27.50. A Dictionary of Science, Literature, and Art. Edited by W. T. BeakUe and Eev. Geo. W. Cox. New and enlarged edition. Watt's Dictionary of Chemistry. Supplementary Volume, 8vo. Cloth. $9.00. This volume brings the Record of Chemical Discovery down to the end of the year 1869, including also several additions to, and corrections of, former results which have appeared in 1870 and 1871. Complete Sets of the Work, New and Revised edition, i4cluding above supplement. 6 vols. 8vo. Cloth. $62.00. Rammelsberg's Chemical Analysis. 8vo. Cloth. $2.25. GUIDE TO A COUESE OF QUANTITATIVE CHEMICAL ANALYSIS, ESPECIALLY OF MINEEALS AND FUR- NACE PEODUCTS. Illustrated by Examples. By C. F. Eammelsbeeg. Translated by J. Towxek, M.D. This work has been translated, and is now published expressly for those students in chemistry whose time and other studies in colleges do not permit them to enter upon the more elaborate and ezpensive treatises of Presenius and others. It is the condensed labor of a master in chemistry and of a prac- tical analyst. 18 8GIENTIFIG BOOKS PUBLISHED BT Eliot and Storer's Qualitative Chemical Analysis. New Edition, Revised. 12mo. Illustrated. Cloth. $1.50. A COMPENDIOUS MANUAL OF QUALITATIVE CHEMI- CAL ANALYSIS. By Chaeles W. Eliot and Frank H. Sxouek. Eevised with the Cooperation of the Authors, by William Eip- lET Nichols, Professor of Chemistry in the Massachusetts Insti- tute of Technology. " This Manual has great merits as a practical introduction to the science and the art of which it treats. It contains enough of the theory and practice of qualitative analysis, " in the wet way," to bring out all the reasoning in- Tolved in the science, and to present clearly to the student the most approved methods of the art. It is specially adapted for exercises and experiments in the laboratory; and yet its classifications and manner of treatment are so systematic and logical throughout, aa to adapt it in a high degree to that higher class of students generally who desire an accurate knowledge of the practical methods of arriving at scientific facts." — Lutheran ObserveT. " We wish every academical class in the land could have the benefit of the fifty exercises of two hours each necessary to meister this book. Chemistry would cease to be a mere matter of memory, and become a pleasant experi- mental and intellectual recreation. We heartily commend this little volume to the notice of those teachers who believe in using the sciences as means of mental discipline." — College Courant. Craig's Decimal System. Square 32mo. Limp. 50c. WEIGHTS AND MEASUEES. An Account of the Decimal | System, with Tables of Conversion for Commercial and Scientific Uses. By B. F. Craig, M. D. " The most lucid, accurate, and useful of all the hand-books on this subject that we have yet seen. It gives forty-seven tables of comparison between the English and French denominations of length, area, capacity, weight, and the Centigrade and Fahrenheit thermometers, with clear instructions how to use them ; and to this practical portion, which helps to make the transition as easy as possible, is prefixed a scientific explanation of the errors in the metric system, and how they may be corrected in the laboratory." — Nation. B. VAN NOSTRANB. 19 NTigent on Optics. 12mo. Cloth. $2.00 TREATISE ON OPTICS ; or, Light and Sight, theoretically and practically treated ; with the application to Fine Art and Indus- trial Pursuits. By E. Nugent. With one hundred and three illustrations. " This book is of a practical rather than a theoretical kind, and is de- signed to afford accurate and complete information to aU interested in appli- cations of the science." — Round Table. Barnard's Metric System. 8vo. Brown cloth. $3.00. THE METRIC SYSTEM OF WEIGHTS AND MEASURES. An Address delivered before the Convocation of the University of the State of New York, at Albany, August, 1871. By Fhedekick A. P. BAKNAiiD, President of Columbia College, New York City. Second edition from the Revised edition printed for the Trustees of Columbia College. Tinted paper. " It is the best summary of the arguments in favor of the metric weights and measures with which we are acquainted, not only because it contains in small space the leading facts of the case, but because it puts the advocacy of that system on the only tenable grounds, namely, the great convenience of a decimal notation of weight and measure as well as money, the value of inter- national uniformity in the matter, and the fact thkt this metric system is adopted and in general use by the majority of civilized nations." — The Nation. The Yonng Mechanic. Illustrated. 12mo. Cloth. $1.75. THE YOUNG MECHANIC. Containing directions for the use of all kinds of tools, and for the construction of steam engines and mechanical models, including the Art of Turning in Wood and Metal. By the author of "The Lathe and its Uses," etc From the English edition, with corrections. r 20 BGIENTIFIG BOOKS PUBLISHED BY Harrison's Mechanic's Tool-Book. 12mo. Clotli. $1.50. MECHANIC'S TOOL BOOK, with practical rules and suggestions, for the use of Machinists, Iron Workers, and others. By W. B. Hakeison, Associate Editor of the " American Artisan." Illustra- ted with 44 engravings. " This work is specially adapted to meet the -wants of Machinists and -work- ers in iron generally. It is made up of the work-day experience of an intelli- gent and ingenious mechanic, who had the faculty of adapting tools to various purposes. The practicability of his plans and suggestions are made apparent even to the unpractised eye by a series of well-executed wood engravings."— Philadelphia Inquirer. Pope's Modern Practice of the Elec- tric Telegraph. Seventh edition. 8vo. Cloth $2.00. A Hand-book for Electricians and Operators. By Fiunk L. Pope. Seventh edition. Eevised and enlarged, and fully illustrated. Extract from Letter of Prof. Morse. " I have had time only cursorily to examine its contents, but this examina- tion has resulted in great gratification, especially at the fairness and unpre- judiced tone of your whole work. " Your illustrated diagrams are admirable and beautifully executed. " I think all your instructions in the use of the telegraph apparatus judi- cious and correct, and I most cordially wish you success." mtraci from Letter of Prof. G. W. Hough, of the Dudley Observatory. " There is no other work of this kind in the English language that con- tains in so small a compass so much practical information in the application of galvanic electricity to telegraphy. It should be in the hands of every one interested in telegraphy, or the use of Batteries for other purposes." Morse's Telegraphic Apparatus. Illustrated. 8vo. Cloth. $2.00. EXAMINATION OE THE TELEOEAPHIC APPAPATUS AND THE PEOCESSES IN TELEGAPHY. By Samuel F. B. MoKSE, LL.D., United States Commissioner Paris Universal Exposition, 1867. D. VAJSr NOSTEAND. 21 Sabine's History of the Telegraph. 12iiio. Cloth. $1.25. HISTORY AND PROGRESS OF THE ELECTRIC TELE- GRAPH, with. Descriptions of some of the Apparatus. By Robert Sabine, C. E. Second edition, with additions. Contents. — 1. Early Observations of Electrical Phenomena. 11. Tele- graphs by Frictional Electricity. III. Telegraphs by Voltaic Electricity. IV. Telegraphs by Electro-Magnetism and Magneto-Electricity. V. Tele- graphs now in use. VI. Overhead Lines. VII. Submarine Telegraph Lines. VIII. Underground Telegraphs. IX. Atmospheric Electricity. ShalFner's Telegraph Manual. 8vo. Cloth. $6.50. A COMPLETE HISTORY AND DESCRIPTION OP THE SEMAPHORIC, ELECTRIC, AND MAGNETIC TELE- GRAPHS OF EUROPE, ASIA, AFRICA, AND AMERICA, with 625 illustrations. By Tal. P. Shaffnek, of Kentucky. New edition. Culley's Hand-Book of Telegraphy. 8vo. Cloth. $5.00. A HAND-BOOK OF PRACTICAL TELEGRAPHY. By R. S. Ctjlley, Engineer to the Electric and International Telegraph Company. Fourth edition, revised and enlarged. Foster's Submarine Blasting. 4to. Cloth. $3.50. SUBMARINE BLASTING in Boston Harbor, Massachusetts- Removal of Tower and Corwin Rocks. By John G. Fosteb, Lieutenant-Colonel of Engineers, and Brevet Major- General, U. S. Army. Illustrated with seven plates. List of Plates. — 1. Sketch of the Narrows, Boston Harbor. 3. Townsend's Submarine Drilling Machine, and Working Vessel attending. 3. Submarine Drilling Machine employed. 4. Details of Drilling Machine employed. 5. Cartridges and Tamping used. 6. Fuses and Insulated Wires used. 7. Portable Friction Battery used. 22 SCIENTIFIC BOOKS PUBLISHED BY Barnes' Siibniarine Warfare. 8vo. Cloth. $5.00. SUBMAEINE WAEFARE, DEFENSIVE AND OFFENSIVE. Comprising a full and complete History of the Invention of the Torpedo, its employment in War and results of its use. De- scriptions of the rarious forms of Torpedoes, Submarine Batteries and Torpedo Boats actually used in War. Methods of Ignition by Machinery, Contact Fuzes, and Electricity, and a full account of experiments made to determine the Explosive Force of Gun- powder under Water. Also a discussion of the Offensive Torpedo system, its effect upon Iron-Clad Ship systems, and influence upon Future Naval Wars. By Lieut.-Commander John S. Bakstes, U. S. N. With twenty lithographic plates and many wood-cuts. " A book important to military men, and especially so to engineers and ar- tillerists. It consists of an examination of the various offensive and defensive engines that have been contrived for submarine hostilities, including a discus- sion of the torpedo system, its effects upon iron-clad ship-systems, and its probable influence upon future naval wars. Plates of a valuable character accompany the treatise, which affords a useful history of the momentous sub- ject it discusses. A great deal of useful information is collected in its pages, especially concerning the inventions of ScHOLL and Vekpu, and of JONEs' and Hunt's batteries, as -well as of other similar machines, and the use in submarine operations of gun-cotton and nitro-glycerine."— iV, Y. Times, Randall's Quartz Operator's Hand- Book. 12mo. Cloth. $8.00, QUABTZ OPEEATOE'S HAND-BOOK. By P. M. Eandall. New edition, revised and enlarged. Fully illustrated. The object of this work has been to present a clear and comprehensive ex- position of mineral veins, and the means and modes chiefly employed for the mining and working of their ores — more especially those containing gold and silver. D. VAN NOSTMAND. 23 Mitchell's Manual of Assaying. 8vo. Cloth. $10.00. A MANUAL OF PEACTICAL ASSAYING. By John Mitchell. Third edition. Edited by William Ceookes, F.E.S. In this edition are incorporated all tlie late important discoveries in Assay- ing made in tliis country and abroad, and special care is devoted to the very important Volumetric and Colorimetric Assays, as well as to the Blow-Pipe Assays. Benet's Chronoscope. Second Edition, lUustrated, 4to. Cloth. $3.00. ELECTEO-BALLISTIC MACHINES, and the Schultz Chrono- scope. By Lieutenant-Colonel S. V. Benet, Captain of Ordnance, U. S. Army, Contents. — 1. Ballistic Pendulum. 2. Gun Pendulum. 3. Use of Elec- tricity. 4. Navez' Maxjhine. 5. Vignotti's Machine, with Plates. G.Benton's Electro-Ballistic Pendulum, with Plates. 7, Leur's Tro-Pendulum Machine 8, Schultz's Chronoscope, with two Plates. Michaelis' Chronograpli. 4to, Illustrated. Cloth, $3.00. THE LE BOIJLENG^ CHRONOGEAPH. With three litho- graphed folding plates of illustrations. By Brevet Captain 0 E. MicHAELis, First Lieutenant Ordnance Corps, U. S. Army. " The excellent monograph of Captain Michaelis enters minutely into the details of construction and management, and gives tables of the times of flight calculated uf>on a given fall of the chronometer for all distances. Captain Michaelis has done good service in presenting this work to his brother oflElcers, describing, as it does, an instrument which bids fair to be in constant use in our future ballistic eiperiments.' — ^rwy and Navy Journal. SCIENTIFIC BOOKS PUBLISHED BY Silversmith's Hand-Book. Fourth Edition. niustrated. 12ino. Cloth. $3.00. A PEACTICAL HAND-BOOK FOE MINERS, Metallurgists, and Assayers, comprising the most recent idiprovements in the disintegration, amalgamation, smelting,' and parting of the Precious Ores, with a Comprehensive Digest of the Mining Laws. Greatly augmented, revised, and corrected. By Julius Silversmith. Fourth edition. Profusely illustrated. 1 vol. 12mo.' Cloth. $3.00. One of the most important features of this work is that in -which the metallurgy of the precious metals is treated of. In it the author has endeav- ored to embody all the processes for the reduction and manipulation of the precious ores heretofore successfully employed in Germany, England, Mexico, and the United States, together with such as have been more recently invented, and not yet fully tested — all of which are profusely illustrated and easy of comprehension. Simms' Levelling. 8vo. Cloth. $3.50. A TEEATISE ON THE PRINCIPLES AND PRACTICE OP LEVELLING, showing its application to purposes of Railway Engineering and the Construction of Roads, &c. By Fredekick W. Simms, C. E. From the fifth London edition, revised and corrected, with the addition of Mr. Law's Practical Examples for Setting Out Railway Curves. Illustrated with three lithographic plates and numerous wood-cuts. " One of the most important text-books for the general surveyor, and there is scarcely a question connected with levelling for which a solution would be sought, but that would be satisfactorily answered by consulting this volume." — Mining Journal. " The text-book on levelling in most of our engineering schools and col- leges." — Engineers. "The publishers have rendered a substantial service to the profession, especially to the younger members, by bringing out the present edition of Mr. Simms useful work." — Engineering, D. VAN NOSTBAJSTD. 25 Eads' Naval Defences. 4to. Cloth. $5.00. SYSTEM OF NAVAL DEFENCES. By James B. Eads, C. E. Report to the Honorable Gideon Welles, Secretary of the Navy, February 22, 1868, with ten illustrations. Stuart's Naval Dry Docks. Twenty-four engravings on steel. Fourth Edition. 4to. Clotli. $6.00. THE NAVAL DRY DOCKS OF THE UNITED STATES. By Chaeles B. Sttjaet. Engineer in Chief of the United States Navy. List of Illustrations. Pumping Engine and Pumps— Plan of Dry Dock and Pump-Well -Sec- tions of Dry Dock — Engine House— Iron Floating Gate — Details of Floating Gate— Iron Turning Gate— Plan of Turning Gate— Culvert Gate— Filling Culvert Gates— Engine Bed— Plate, Pumps, and Culvert— Engine House Eoof — Floating Sectional Dock— Details of Section, and Plan of Turn-Tables — Plan of Basin and Marine Railways — Plan of Sliding Frame, and Elevation of Pumps— Hydraulic Cylinder— Plan of Gearing for Pumps and End Floats — Perspective View of Dock, Basin, and Railway- Plan of Basin of Ports- mouth Dry Dock — Floating Balance Dock— Elevation of Trusses and the Ma- chinery—Perspective View of Balance Dry Dock Free Hand Drawing. Profusely Illustrated. 18mo. Cloth. 75 cents. A GUIDE TO ORNAMENTAL, Figure, and Landscape Draw- ing. By an Art Student. Contents.— Materials employed in Drawing, and how to use them— On Lines and how to Draw them— On Shading— Concerning lines and shading, with applications of them to simple elementary subjects— Sketches from Na- ture. 26 SCIENTIFIC BOOKS FUBLISHED BY Minifies Mechanical Drawing. EigJith Edition. Royal 8vo. Cloth. $4.00. A TEXT-BOOK OF GEOMETEIOAL DEAWING for the use of Mechanics and Schools, in which the Definitions and Eules of Geometry are famiH^rly explained ; the Practical Problems are arranged, from the most simple to the more complex, and in their description technicahties are avoided as much as possible. With illustrations for Drawing Plans, Sections, and Elevations of Buildings and Machinery ; an Introduction to Isometrical Draw- ing, and an Essay on Linear Perspective and Shadows. Illus- trated with over 200 diagrams engraved on steel. By Wm. MiNiFiE, Architect. Eighth Edition. With an Appendix on the Theory and Application of Colors. " It is the best work on Drawing that we have ever seen, and is especially a text-book of Geometrical Drawing for the use of Mechanics and Schools. No young Mechanic, such as a Machinist, Engineer, Cabinet-Maker, Millwright, or Carpenter, should be without it." — Scientific American. " One of the most comprehensive works of the kind ever published, and can- not but possess great value to builders. The style is at once elegant and sub- stantial. " — Pennsylvania Inquirer. " Whatever is said is rendered perfectly intelligible by remarkably well- executed diagrams on steel, leaving nothing for mere vague supposition ; and the addition of an introduction to isometrical drawing, linear perspective, and the projection of shadows, winding up with a useful index to technical terms." — Glasgow Mechanics' Journal. Ht^" The British Government has authorized the use of this book in their schools of art at Somerset House, London, and throughout the kingdom. Minifie's G-eometrical Drawing. New Edition. Enlarged. 12mo. Cloth. $2.00. GEOMETEIOAL DEAWING. Abridged from the octavo edition, for the use of Schools. Illustrated with 48 steel plates. New edition, enlarged. " It is well adapted as a text-book of drawing to be used in our High Schools and Academies where this useful brauch of the fine arts has been hitherto too much neglected. "^£(?si(?«. Journal. D. VAN' NOSTMAJSTD. 27 Bell on Iron Smelting. 8vo. Cloth. $6.00. CHEMICAL PHENOMENA OF lEON SMELTING. An ex- perimental and practical examination of the circumstances which determine the capacity of the Blast Furnace, the Temperature of the Air, and the Proper Condition of the Materials to be operated upon. By I. Lowthian Bell. " The reactions -which take place in every foot of the blast-furnace hare been investigated, and the nature of every step in the process, from the intro- duction of the ravf material into the furnace to the production of the pig iron, has been carefully ascertained, and recorded so fully that any one in the trade can readily avail themselves of the knowledge acquired ; and we have no hes- itation in saying that the judicious application of such knowledge will do much to facilitate the introduction of arrangements which will still further economize fuel, and at the same time permit of the quality of the resulting metal being maintained, if not improved. The volume is one which no prac- tical pig iron manufacturer can afford to be without if he be desirous of en- tering upon that competition which nowadays is essential to progress, and in issuing such a work Mr. Bell has entitled himself to the best thanks of every member of the trade." — London Mining Journal. King's Notes on Steam; Tliirteenth Edition. 8vo. Cloth. $3.00. LESSONS AND PRACTICAL NOTES ON STEAM, the Steam- Engine, Propellers, &c., &c., for Young Engineers, Students, and others. By the late W. R. King, U. S. N. Revised by Chief- Engineer J. W. King, U. S. Navy. " This is one of the best, because eminently plain and practical treatises on the Steam Engine ever published. ' — Philadelphia Press. This is the thirteenth edition of a valuable work of the late W. H. King, XT. S. N. It contains lessons and practical notes on Steam and the Steam En- gine, Propellers, etc. It is calculated to be of great use to young marine en- gineers, students, and others. The text is illustrated and explained by nu- merous diagrams and representations of machinery. —Boston Daily Adver- tiser. Text-book at the U. S. Naval Academy, Annapolis. 28 SCIENTIFIC BOOKS PUBLISHED BY Burgh's Modern Marine Engineering. One thick 4to vol. Cloth. $25.00. Half morocco. $30.00. MODEEN MAEINE ENGINEERING, applied to Paddle and Screw Propulsion. Consisting of 36 Colored Plates, 259 Practical Wood-cut Illustrations, and 403 pages of Descriptive Matter, the "whole being an exposition of the present practice of the follow- ing firms : Messrs. J. Penn & Sons ; Messrs. Maudslay, Sons & Field ; Messrs. James Watt & Co. ; Messrs. J. & G. Eennie ; Messrs. E. Napier & Sons ; Messrs. J. & W. Dudgeon ; Messrs. Eavenhill & Hodgson ; Messrs. Humphreys & Tenant ; Mr. J. T. Spencer, and Messrs. Forrester & Co. By N. P. BtrEGn, Engineer. Principal Contents. — General Arrangements of Engines, 1 1 examples — General Arrangement of Boilers, 14 examples — General Arrangement of Superkeaters, 11 examples — Details of 'Oscillating Paddle Engines, 84 ex- amples — Condensers for Screw Engines, both Injection and Surface, 20 ex- amples — Details of Screw Engines, 20 examples — Cylinders and Details of Sprew Engines, 21 examples — Slide Valves and Details, 7 examples — Slide Valve, Link Motion, 7 examples — Expansion Valves and Gear, 10 exam- ples — Details in General, 30 examples — Screw Propeller and Fittings, 13 ex- amples Engine and Boiler Fittings, 28 examples In relation to the Princi- ples of the Marine Engine and Boiler, 33 examples. Notices of the Press. "Every conceivable detail of the Marine Engine, under all its various forms, is profusely, and we must add, admirably illustrated by a multitude of engravings, selected from the best and most modern practice of the first Marine Engineers of the day. The chapter on Condensers is peculiarly valu- able. In one word, there is no other work in existence which will bear a moment's comparison with it as an exponent of the skill, talent and practical experience to which is due the splendid reputation enjoyed by many British Marine Engineers."— ^/J^fmeer. " This very comprehensive work, which was issued in Monthly parts, has just been completed. It contains large and full drawings and copious de- scriptions of most of the best examples of Modern Marine Engines, and it is a complete theoretical and practical treatise on the subject of Marine Engi- neering."— -American. Artisan. This is the only edition of thu above work with the beautifully colored plates, and it is out of print in England. r D. VAN WOSTRAN-JD. ^ • .1-^' Bourne's Treatise on tlie Steam En- gine. Ninth Edition. lUustrated. 4to. Cloth. $15.00. TEEATISE ON THE STEAM ENGINE in its various applica- tions to Mines, Mills, Steam Navigation, Railways, and Agricul- ture, "with, the theoretical investigations respecting the Motive Power of Heat and the proper Proportions of Steam Engines. Elaborate Tables of the right dimensions of every part, and Practical Instructions for the Manufacture and Management of every species of Engine in actual use. By Johk BouEifE, being the ninth edition of " A Treatise on the Steam Engine," by the "Artisan Club." Illustrated by thirty-eight plates and five hundred and forty-six wood-cuts. As Mr. Bourne's work has the great merit of avoiding unsound and imma- ture views, it may safely be consulted by all who are really desirous of ac- quiring trustworthy information on the subject of which it treats. During the twenty-two years which have elapsed from the issue of the first edition, the improvements introduced in the construction of the steam engine have been both numerous and important, and of these Mr. Bourne has taken care to point out the more prominent, and to furnish the reader with such infor- mation as shall enable him readily to judge of their relative value. This edi- tion has been thoroughly modernized, and made to accord with the opinions and practice of the more successful engineers of the present day. All that the book professes to give is given with ability and evident care. The scien- tific principles which are permanent are admirably explained, and reference is made to many of the more valuable of the recently introduced engines. To express an opinion of tho value and utility of such a work as The Artisan Club's Treatise on the StQam Enjine, which has passed through eight editions already, would be superfluous ; but it may be safely stated that the work is worthy the attentive study of all either engaged in the manufacture of steam engines or interested in economizing the use of steam. — Mining Journal. Isherwood's Engineering Precedents. Two Vols, in One. 8vo. Cloth. $2.50. ENGINEERINa PRECEDENTS FOR STEAM MACHINERY. Arranged in the most practical and useful manner for Engineers. By B. F. IsHEEWooD, Civil Engineer, U. S. Navy. With illus- trations. ' 30 SCIENTIFIC BOOKS PUBLISHED BY Ward's Steam for the Million. New and Mevised Edition, 8vo. Cloth. $1.00. STEAM FOE THE MILLION. A Popular Treatise on Steam and its Application to the Useful Arts, especially to Naviga- tion. By J. H. Waed, Commander U. S. Navy. New and re- vised edition. A most excellent work for the young engineer and general reader. Many facts relating to the management of the boiler and engine are set forth with a simplicity of language and perfection of detail that bring the subject home to the reader. — American Engineer. Walker's Screw Propulsion. 8vo. Cloth. 75 cents. NOTES ON SCEEW PEOPULSION, its Eise and History. By Capt. W. H. Walkeb, U. S. Navy. Commander Walker's book contains an immense amount of concise practi- cal data, and every item of information recorded fully proves that the various points bearing upon it have been -well considered previously to expressing an opinion. — London Mining Journal. I Page's Earth's Crust. 18mo. Cloth. 75 cents. THE EAETH'S CEUST : a Handy Outline of Geology. By David Page. " Such a work as this was much wanted — a work giving in clear and intel- ligible outline the leading facts of the science, without amplification or irk- some details. It is admirable in arrangement, and clear and easy, and, at the same time, forcible in style. It will lead, we hope, to the introduction of Geology into many schools that have neither time nor room for the study of large treatises." — The Museum. D. VAN NOSTBAN'I). 31 Rogers' Geology of Peimsylvania. 3 Vols. 4to, with Portfolio of Maps. Cloth. $30.00. THE GEOLOGY OF PENNSYLVANIA. A Government Sur- vey. With a general view of the Geology of the United States, Essays on the Coal Formation and its Fossils, and a description of the Coal Fields of North America and Great Britain. By Henry Darwin Rogers, Late State Geologist of Pennsylvania. Splendidly illustrated with Plates and Engravings in the Text. It certainly should be in every public library ^aroughout the country, and likewise in the possession of all students of Geology. After the final sale of these coj)ie8, the work will, of course, become more valuable. The work for the last five years has been entirely out of the market, but a few copies that remained in the hands of Prof. Rogers, in Scotland, at the time of his death, are now offered to the public, at a price which is even below what it was originally sold for when first published. Morfit on Pure Fertilizers. With 28 Illustrative Plates. 8vo. Cloth. $20.00. A PRACTICAL TREATISE ON PURE FERTILIZERS, and the Chemical Conversion of Rock Guanos, Marlstones, Coprolites, and the Crude Phosphates of Lime and Alumina Generally, into various Valuable Products. By Campbell Morfit, M.D., F.C.S. Sweet's Report on Coal. 8vo. Cloth. $8.00. SPECIAL REPORT ON COAL ; showing its Distribution, Qassi- fication, and Cost delivered over different routes to various points in the State of New York, and the principal cities on the Atlantic Coast. By S. H. Sweet. With maps. Colburn's Gas Works of London. 13mo. Boards. 60 cents. GAS WORKS OF LONDON. By Zerah Coxbubn. 82 SCIENTIFIC BOOKS PUBLISHED BY The Useful Metals and their Alloys ; Scoflfren, Tniran, and. others. Fifth Edition. 8vo. Half calf. $3.75. THE USEFUL METALS AND THEIR ALLOYS, inclnding MINING VENTILATION, MINING JUEISPRUDENCE AND METALLUEGIO CHEMISTRY employed in the conver- sion of IRON, COPPER, TIN, ZINC, ANTIMONY, AND LEAD ORES, with their applications to THE INDUSTRIAL ARTS. By John Scofficen, William Trtjran, William Clay, Robert Oxland, William Faiebaikn, W. C. Aitkin, and Wil- liam VosE Pickett. Collins' Useful Alloys. 18mo. Flexible. 75 cents. THE PRIVATE BOOK OF USEFUL ALLOYS and Memo- randa for Goldsmiths, Jewellers, etc. By James E. Collins This little book is compiled from notes made by the Author from the papers of one of the largest and most eminent Manufacturing G-oldsmiths and Jewellers in this country, and as the firm is now no longer in existence, and the Author is at present engaged in some other undertaking, he now offers to the public the benefit of his experience, and in so doing he begs to state that all the alloys, etc., given in these pages may be confidently relied on as being thoroughly practicable. The Memoranda and Receipts throughout this book are also compiled from practice, and will no doubt be found useful to the practical jeweller. — Shirley, July, 1871. Joynson s Metals Used in Construction. 12mo. Cloth. 75 cents. THE METALS USED IN CONSTRUCTION: Iron, Steel, Bessemer Metal, etc., etc. By Fiuncis Hekbeet Jotnson. Il- lustrated. " In the interests of practical science, we are bound to notice this work ; and to those who wish further information, we should say, buy it ; and the outlay, we honestly believe, will be considered well spent." — Scientific Review. D. VAN JSrOSTEAWD. 33 Holley's Ordnance and Armor. 493 Engravings. Half EoaH, $10.00. Half Eussia, $12.00. A TEEATISE ON ORDNANCE AND AEMOR-Embracing Descriptions, Discussions, and Professional Opinions concerning the MATEfiiAL, Fabrication, Eequirements, Capabilities, and En- durance of European and American Guns, for Naval, Sea Coast, and Iron-clad Warfare, and their Rifling, Projectiles, and Breech-Loading; also, Results of Experiments against Armor, from Official Records, with an Appendix referring to Gun-Cotton', Hooped Guns, etc., etc. By Alexander L. Hollet, B. P. 948 pages, 493 Engravings, and 147 Tables of Results, etc. Contents. Chapter I-Standard Guns and their Fabrioation Described: Section 1. Hooped Guns; Section 2. Solid Wrought Iron Guns; Section 3. Solid Steel Guns ; Section 4. Cast-iron Guns. Chapter II.-The Requirements of Guns. Armor: Section 1. The Work to be done; Section 2. Heavy Shot at Low Ve- ocities; Sections Small Shot at High Velocities; Section 4. The two Sys- tems Combined ; Section 5. Breaching Masonry. Chapter III.-The Strains and Structure of Guns: Section 1. Resistance to Elastic Pressure ; Section 2. i he Effects of Vibration; Sectioa 3. The Effects of Heat. Chapter IV — Cannon Metals and Processes of Fabrication: Section 1. Elasticity and Ductil ity; Section 2. Cast-iron; Section 3. Wrought Iron; Section 4. Steel; Sec- tion 5. Bronze; Section 6. Other Alloys. Chapter V.-Rifling and Projec- tiles; Standard Forms and Practice Described; Early Experiments; The Centring System; The Compressing System ; The Expansion System ; Armor Punching Projectiles; Shells for Molten Metal; Competitive Trial of Rifled Guns, 1862; Duty of Rifled Guns: General Uses, Accuracy, Range, Velocity Strain, Liability of Projectile to Injury ; Firing Spherical Shot from Rifled Guns; Material for Armor-Punching Projectiles ; Shape of Armor-Punching Projectiles; Capacity and Destructiveness of Shells; Elongated Shot from Smooth Bores; Conclusions; Velocity of Projectiles (Table \ Chapter VI — Breech-Loading Advantages and Defects of the System; Rapid Firing and Cooling Guns by Machinery; Standard Breech-Loaders Described. Par't Sec- ond : Experiments against Armor ; Account of Experiments from Official Records in Chronological Order. AppENDix.-Report on the Applical^on of Gun-Cotton to Warlike Purposes— British Association, 1863 ; Manufacture and Experiments in England ; Guns Hooped with Initial Tension— History; How Guns Burst, by Wiard, Lyman's Accelerating Gun; Endurance of p'arrott and Whitworch Guns at Charleston ; Hooping old United States Cast-iron Guns ; Endurance and Accuracy of the Armstrong 600-pounder; Competitive Trials with 7-inch Guns. SCIENTIFIC BOOKS PUBLISHED BY Peirce's Analytic Mechanics. 4to. Cloth. $10.00. SYSTEM OF ANALYTIC MECHANICS. Physical and Celestial Mechanics. By Benjamin Peirce, Perkins Professor of Astronomy and Mathematics in Harvard University, and Consulting As- tronomer of the American Ephemeris and Nautical Almanac. Developed in four systems of Analytic Mechanics, Celestial Mechanics, Potential Physics, and Analytic Morphology. " I have re-examined the memoirs of the great geometers, and have striven to consolidate their latest researches and their most exalted forms of thought into a consistent and uniform treatise. If I have hereby succeeded in open- ing to the students of my country a readier access to these choice jewels of intellect ; if their brilliancy is not impaired in this attempt to reset them ; if, in their own constellation, they illustrate each other, and concentrate a stronger light upon the names of their discoverers , and, still more, if any gem which I may have presumed to add is not wholly lustreless in the collec- tion, I shall feel that my work has not been in -Extract from the Pre- face. Bnxt's Key to Solar Compass. Second Edition. Pocket Book Form. Tuck. $2.50. KEY TO THE SOLAR COMPASS, and Surveyor's Companion ; comprising all the Rules necessary for use in the field; also, Description of the Linear Surveys and Public Land System of the United States, Notes on the Barometer, Suggestions for an outfit for a Survey of four months, etc., etc., etc. By W. A. BuBT, U. S. Deputy Surveyor. Second edition. Chanvenet's Lunar Distances. 8vo. Cloth. $2.00. NEW METHOD OF CORRECTING LUNAR DISTANCES, and Improved Method of Finding the Error and Rate of a Chro- nometer, by equal altitudes. By Wm. Chaxjvenet, LL.D., Chan- cellor of Washington University of St. Louis. B. VAN NOSTRAND. 35 Jefiers' Nautical Surveying. niuatrated with 9 Copperplates and 31 Wood-cut Illustrations. 8vo. Cloth. $5.00. NAUTICAL SURVEYING. By William N. Jeppees, Captam U. S. Navy. ^ Many books have been written on each of the subjects treated of in the sixteen chapters of this work; and, to obtain a complete knowledge of geodetic surveying requires a profound study of the whole range of mathe- matical and physical sciences; but a year of preparation should render any intelligent officer competent to conduct a nautical survey. Contents.— Chapter I. Formulae and Constants Useful in Surveying II. Distinctive Character of Surveys. III. Hydrographic Surveying under Sail ; or, Running Survey. IV. Hydrographic Surveying of Boats ; or. Har- bor Survey. V. Tides-Definition of Tidal Phenomena-Tidal Observations. VI. Measurement of Bases- Appropriate and Direct. VII. Measurement of the Angles of Triangles— Azimuths— Astronomical Bearings. VIII. Correc- tions to be Applied to the Observed Angles. IX. Levelling-Difference of Level. X. Computation of the Sides of the Triangulation— The Three-point Problem. XI. Determination of the Geodetic Latitudes, Longitudes, and Azimuths, of Points of a Triangulation. XIL Summary of Subjects treated of in precedmg Chapters-Examples of Computation by various Formula XIII. Projection of Charts and Plans. XIV. Astronomical Determination of Latitude and Longitude. XV. Magnetic Observations. XVL Deep Sea Soundings. XVIL Tables for Ascertaining Distances at Sea, and a full Index. List of Plates. Plate I. Diagram Illustrative of the Triangulation. IL Specimen Page of Field Book. III. Running Survey of c Coast. IV. Example of a Running Survey from Belcher. V. Flying Survey of an Island. VI. Survey of a Shoal. VII. Boat Survey of a River. VIIL Three-Point Problem. DC Triangulation. Coffin's Navigation. Fifth Edition. 12mo. Cloth. $3.50. NAVIGATION AND NAUTICAL ASTEONOMY. Prepared for the use of the U. S. Naval Academy. By J. H. C. 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