Scienfciflq and Medical Books, aiii?an objects of Natural History. A:,,®' rOOTE, M D. 122.J Belmont Ave.. Philadelphia, Pa. FRANKLIN INSTITUTE LIBRARY PHILADELPHIA CIass..G Book .Z4.?.r Accession . . C ^ _3 Given by „ . t € ...td.r.. 1 Digitized by the Internet Archive in 2015 https://archive.org/details/handbookonsilexeOOfeuc A HAND-BOOK ON SILEX, EMBRACED IN THREE PRACTICAL TREATISES : I. OF SOLUBLE GLASS, AND ALL ITS APPLICATIONS IN THE ARTS. II. ON GLASS MAKING, IN ALL ITS DETAILS. III. A GUIDE FOR SOAP MAKING, THE MANUFACTURE OP ALL SOAPS iiljD THEII? MA^HUTHATIOUSi ^ ^ ^ ^ " CONTAINING ’ Thousands of Formulae f^r Wood und’ Timpdr Fire 'aid Set Iroof, Silicifying Stones, Mortars- Cotorete^aai Dydr^llc* Lime,’ Wliito Washes^ Paints and Cements, and how to Proteot Wooden Shingles, Pavements, Eail-Eoad Sleepers, &o., &c. By Dr. LEWIS FEUCHTW ANGER, CHEMIST AND MINERALOGIST. PUBLISHED BY L. & J. W. FEUCHTW ANGER, No. 55 Cedar Street. 1871 . Entered according to Act of Congress, in the year eighteen hundred and seventy-one*, BY Dr. lewis FEUCHTWANGER, ‘ ^ ' o ® •Ii>th€«ofiice.o/.th^ ybfjtrian of Congress, at Washingtop, ^ JOHN W. AMEBMAN, PRINTER No. 47 Cedar Street, N. Y. H^TRODUCTORY. The first edition of the “ Practical Treatise on Soluble Glass” being entirely exhausted, and the demand for the same daily increasing, have obliged the author to issue a new book, under the name of “ A Hand-book on Silex,” wliich is to embrace three separate treatises : 1. That on Soluble Glass ^ with all the latest applications in the arts, and for wood and stone. 2. The art of glass making in all its details. 3. The soap maker’s guide for the pro- duction of soaps of every grade, such as family, toilet and silicated. The Author has bestowed particular atten- tion on this work, having been encouraged by many flattering testimonials of approval by the Press and the public at large. He has introduced- a great many improvements gathered from his own experiments, and published in many periodicals of the country, and vydiich form at the present moment a very important branch of domestic industry. ’ The soluble glass has, of late, become paramount in the arts, as many trades can- not dispense with it in their pursuits, and more so since the great confiagration of the City of Chicago, v/hich took place on the 9th and 10th of October, where one- fifth of it was laid waste and destroyed ; all the public buildings, churches, court-house, the principal business houses, and many wooden-roofed houses inhabited by poor people. This disaster has aroused in the minds of mauy men, and journalists in particular, the question whether or not such a catastrophe, by resorting to more 4 Se IV INTEODUCTOEY. precautions in the construction of buildings could not be, in future, either entirely avoided, or conflagrations of any magnitude be stayed in the sudden progress of the fiery element. Well-informed men have so expressed their belief in letters to the Author, that the steeples of high buildings caught from the sparks flying in all directions from the contagion, and could with ease have been saved by a judicious management. The editor of the Scientific American of November 11th makes the following perti- nent remarks in his leader resjoecting the great fire, which we copy here with alacrity, for they coincide entirely with the^Author’s ideas, and they inspire the hope that all the newspapers in the United States may take due notice of such valuable hints thrown out, and copy them in their local papers, so that all their readers may profit thereby, and follow out such precautions which this journal recom- mends, and whereby, at trifling expense and trouble, millions of dollars worth of property can be saved to owners and insurance companies. He speaks of suitable building material in the follow- ing article : “ Recent events have turned the attention of thoughtful people to a consideration of the question of building ma- terial for large towns. It no longer appears proper to permit indiscriminate constructions, where the safety of a Avhole community may be endangered. We have, in large cities, superintendents of buildings, but they gene- rally confine their attention to the question of security against falling, and not to the character of the building material, excepting in so far as wooden structures may be prohibited in certain districts. There would now ap- pear to be cogent reasons why commissioners should be appointed to secure greater precautions than the mere question of wood and iron. A mixed commission, com- posed of builders, architects, underwriters, firemen and INTRODUCTORY. V scientific experts, could be appointed to study tbe whole subject and report thereon to the government. The com- mission could very properly decide upon the survey of streets, and the width, the kind of pavement and flagging to be used. They could lay down water pipes and es- tablish hydrants at suitable distances, and see to proper arrangements for extinguishing any fire's that might arise ; but the most important duty to be assigned to them would be the control of building material in certain sections of the city. “ By insisting upon the construction of a row of build- ings, up and down and across town, as nearly fireproof as it is possible to make them, a wall, impervious to fire and constituting a barrier impassable to 'any ordinary conflagration, would arrest the flames and save whole sections of the city. A street, built up entirely of fire- proof buildings, would be a novelty ; but in the light of recent events, it would appear to offer great protection, and it may be worth while to designate what streets shall be of this character, and then insist upon a com- pliance with the prescribed style of building. Having adopted some such plan as this, the commission would have to study the kind of building material best adapted to city structures, combining security and durability with reasonable economy. This opens up the whole question of the comparative value, for building purposes, of wood, iron and stone. They tried wood in Chicago, without having treated any of the material with the numerous agents that have been recommended to render it incom- bustible ; and the sad consequences of this neglect ought to serve as a warning to all other cities. If the wood had been saturated with soluble glass, it could not have been set on fire. Silicate of soda, or soluble glass, can be obtained in suffciently large quantities, and at such reasonable rates, as to admit of the preparation of the VI INTEODUCTORY. shingles, clapboards, and all exposed portions of frame buildings. Any such precaution as this has the doubl® advantage of protecting against hre, and securing against decay; and, in the long run, would be found to be the greatest economy. “ If people will insist upon constructing frame build- ings in large towns, they ought to be compelled to render them essentially fireproof by the above chemical mixture. So many experiments have been tried with soluble glass, that the security it affords against fire and decay may be considered as fully determined. Wood thus prepared will char and smolder, but will not burst into flame ; and hence there could be no scattering of cinders or blowing about of firebrands. ‘‘ Where frame buildings are tolerated, the fire marshal might justly insist upon a chemical preparation of the wood — an operation that could easily enough be done, if it were imperatively required. The scientiflc experts on the commission would be apt to report in accordance with the princi23les laid down above, and by degrees the dealers in lumber would learn how to furnish a building material nearly as durable as iron. “ In reference to the use of iron for houses, the facts, that it is employed to a large extent, and that we are constantly acquiring greater skill in its manipulation and management, are sufficient 2 >roof of its j)racticability. In Chicago, however, this material proved unavailing, for the reason that the wooden structures made a fire hotter far than a blast furnace constructed to melt 2 >ig iron. No iron could stand such a heat, and it melted down like wax. This was not the fault of the iron, but caused by the neglect to prepare the wood against such an emer- gency ; and no one will be likely to condemn iron struc- tures on account of their failure in Chicago. “ A third building material is stone, and this may be INTRODUCTOEY. VI 1 divided into the native and artificial. There are a good many varieties of stone suitable for building purposes ; but the cost of quarrying, transportation and working, is so great in this country as almost to shut this mateiial out of competition. This objection does not apply to artificial stone. The lime and sand required to make artificial stone can be found nearly everywhere. They can be mixed by simple machinery, and require no labor to cut them into shape ; but the plastic material can be run into any kind of a mold, where it dries in a few hours, and one layer after another can be carried up- in marvel- ously short time. “ For rapidity of construction, for durability, for secu- rity against fire, for warmth and ventilation, for dryness and health, for economy, for architectural effects, there is nothing like artificial stone ; and we look upon this material as the most suitable for cities, and as probably destined to vsupersede all other. It only needs the poiDular dissemination of information on the subject to occasion a demand for artificial stone; and as soon as such a demand is created, this material can be furnished in any quantity in all parts of the country ; and we shall have it for our cellars and our ice houses, our sewers, cisterns, w'ells, water pipes, paths, roads, schools, churches, dwelling houses and stores, in a way that will make us wonder how we ever performed the slow and tedious labor of hewing out stones or laying up brick, when we could have formed a whole house at one casting — as Kru23p pours the melted steel into molds, and produces a cannon of any size.” As regards the Treatise on Glass Maldng^ which forms the second part of this work, it may be worth mentioning, that many of the western glass manufacturers have ex- pressed tlieir wish to be informed of the late improve- ments which have been going on in Europe, as far as they Vlll INTKODUCTORY. have been displayed in the French Exposition of 1867, of colored, optical, pl^te and other glass, all of which have silex as the base ; wherefore, he resolved to begin with a fall practical description of the glass house, from the first construction to the manufacture of all kinds ol glass, such as the tumbler and mirror glass. The Author believes he has given as clear and succinct information as can be had, in a practical manner. The S)Oap Maher’s Gtdde, which forms the third part of this work, has been added for several reasons ; the principal of which was, that soluble glass and fine fiint have, of late years, been largely consumed in the manu- facture of soap ; the first as a useful vehicle for domestic use, and for washing and fulling wool, and the latter for sophisticating soaps ; and the Author has taken pains to give a full description of the manipulation of raw ma- terials used in every species of soap, and all the required information, as to be able to compete with any manufac- turer; in other words, this treatise is intended as a full guide in soap making. Since the Author has laid out this work to be alto- gether practical, he has omitted here the essays on the functions of carbonic acid and limestones ; but the alkalies and silex in the former edition have been incor- porated in the present work. Trusting that the public may accept with indulgence the following work, if in some places the phraseology or othography should sound harsh on an American ear, for the reason that the impaired state of his health frequently prevented him from bestow- ing the proper attention in correcting proofs ; he now de- livers it, confidently believing that it may prove service- able and useful for all the intended objects. PREFACE TO THE PRESENT WORK. In offering the present edition to the public, the Author begs to state, that he felt induced to change his jDro- gramme from the first edition, for the following reasons, viz. : The long and detailed discussions on soluble glass in the first having been received with great favor, it was advisable to add in the present all improvements which have been suggested by various authors for the last year ; he has devoted in the present work two hundred pages in the description of the materials used in the manufac- ture and various applications of the same, to a great many branches of domestic industry. He has omitted the philosophical essays of the first edition, on account of his resolution to publish a practical book. The whole wmrk is divided in three parts : I. The soluble glass, and its various applications. IL Glass making in all its details. III. Soap making ; a guide for the production of every species of soap, the family, toilet and silicated. The following works have served the writer in his compilations with the greatest satisfaction, such as Mus- ]>rat’s Encyclopedia, where the subject on glass is so ably treated. And in his guide for soap making he has been principally assisted by I)r. Adolph Ott’s book on the art of manufacturing soap and candles. PREFACE TO FIRST EDITION. The object of this Treatise on Soluble or Water Glass, is to give some information to the many inquiries which have been directed to the Author for some years past, in what manner and purpose this valuable preparation, so highly recommended by the various scientific journals, can be usefully employed. There is, as yet, no book published, treating on all its applications, with the excep- tion of a pamphlet in French by Kuhlmann in 1859, con- taining mostly memoirs to the French Academy, and the application of the water glass by calico printers and cot- ton manufacturers. It is for this reason that the Author felt the necessity of compiling all that is scattered, about the various uses of the soluble glass, in all the journals and Patent Olfice reports. Not a day passes without re- ceiving orders for samples, either in dry, liquid or jelly state, with particular requests for exj)licit directions ; nor does a day pass without being importuned by strangers and curious people, all desirous for information how the soluble glass would answer for many purposes in domestic economy. The soap maker, who has been using it in Europe and this country for a number of years, wants to know more on the subject of producing a cheap and good soap. For slates, for a good and cheap whitewash, for a fireproof paint, for a hoop skirt or shirt collar, for a mucilage, a fire and waterproof cement, and for many hundred other uses, the inquiries are made; and thousands of samples have, for the last ten years, been distributed to the inquisitive and speculative applicants. PKEFAOE TO FIRST EDITION. XI It is generally known that the Author was the first to introduce the soluble glass in the United States, and has devoted much time in experimenting with it ; and he has succeeded, after many fruitless trials, to create a demand in many branches of industry. From the extensive list of patents issued in Europe and the United States, he has collected all information, along with that obtained from the scientific and practical journals, and experimenters will find in this Treatise the various uses and applica- tions.. Kuhlmann’s Pamphlet, the Mining and Engineer- ing Journal, the Transactions of the American Institute, the Manufacturer and Builder, Scientific American, the Annual of Scientific Discovery, have all furnished ma- terial for this Treatise. ’ Many interesting topics, such as the origin of saltpetre, the nitrate of soda, and the manufacture of blanc fix, had to be related, and will, no doubt, interest the general reader. Particular attention has been bestowed upon the for- mation of hydraulic cements and artificial stone, for the reason that more inquiries and experiments are performed in this branch than in any other of domestic economy. The natural stones, such as the brown stone, sandstone, limestone and brick building, will, sooner or later, after an exposure to the atmospheric elements, and rain and frost, become decomposed ; cracks and fissures will then produce the deterioration, while coated with the soluble glass and mixing the mortar with the same and impreg- nating the bricks, much is gained for their preservation. It is somewhat remarkable, that long before this the art of making artificial stone has not been brought to perfection. Yet, if we may judge from the great and increasing variety of, processes, patented and otherwise, which now press their claims upon public notice, the time is ripe for the introduction of any process which can XU PREFACE TO FIRST EDITION. demonstrate practically its capacity to fulfill tlie require- ments of the case. Every opportunity has been afforded us to examine and test specimens of artificial stone, and we have met with many kinds which have very little merit. Some, however, are really good stones, and, as such, must, in our opinion, come largely into use. The silicification of rail-road sleepers, wooden rails and blocks for pavement is in importance next to the prepara- tion of artificial stone. The comparison of the wooden and iron rails has also been clearly stated here, and the future will, no doubt, bring to light many facts here stated, but not yet put to practice. The advantages of the wooden block pavement over all other kinds, such as Macadamizing, graveling, cinders, boulders, and stone blocks, are numerous, and if properly laid, will withstand long years of the hardest kind of travel; and there are but two important points in the wooden pavement to be observed, which are a firm and even foundation, and the good silicification of the foundation planks and blocks. The reason why the Author has devoted so much space upon hydraulic limes, mortars, paints, whitewashes, and the preparation for guarding timber against dry rot and conflagration, is solely to prove and make it plausible that the application of soluble glass possesses great ad- vantages, and may, with very little expense, give addi- tional safeguards. The formulae and directions for preparing an immense number of the most useful vehicles, cements for building and side-walks, paints, varnishes, &c., cannot but be very acceptable. SOLUBLE GLASS, Also called water glass, liquid quartz, or alkaline silicate, consists essentially of silex and one or two alkalies heated to fusion ; it is, therefore, a silicate, either as silicate of potassa, silicate of soda, or a mix- ture of these two alkalies, a silicate of potassa and lime, the composition of Bohemian glass, or a silicate of soda and lime, like the English crown or spread glass ; and if there is oxide of lead added to the mix- ture of silex and alkalies, and heated to continued fusion, we obtain thereby a Hint glass, crystal glass, or strass, a paste used in mock jewelry. According to the quantity of alkali employed in the mixture, the product is made soluble or insoluble. Bottle and window glass, for instance, which contain less alkali and some oxide of iron and alumina, (clay,) are more difficult of fusion than other kinds. The soluble glass was brought to practicable uses by Pro- fessor Fuchs, of Munich, in Bavaria, in the year 1823, by igniting strongly in a reverberatory furnace or crucible for six hours, a mixture of 10 parts of pearl ashes, 15 parts of powdered quartz, or fine sand, and 1 part charcoal ; the mass was then pulverized and added in small portions to boiling water, until the whole is dissolved and evaporated to a specific gravity of 1.25, at which point the carbonic acid of tlie at- 2 14 SOLUBLE GLASS. mospheric air ceases to decompose it. The highest concentration of the liquid is 42° B. 5 when still more evaporated it is obtained in a solid form, resembling common glass, but much softer and more fusible. The liquid standing about 30° B. is, however, the most proper menstruum for application to wood, and preventing the same from being attacked or kindled by sparks of fire, such as shingle roofs, wooden bridges and farm houses. Fuchs prepared four different li- quids, and employed them in his experiments : 1 . The simple water glass, made from potassa. 2. The soda water glass. 3. The compound of both. 4. Another liquid which he used for fixing paints on a coating on wood, and called the jelly liquid. In order to demonstrate the utility of the water glass in making wood fire-proof, and on the occasion of the burning of the Boyal Theatre at Munich, a wooden shanty was, by order of the King, erected, and coated inside and outside with a weak liquid of silicate of potassa, and was set on fire on each corner ; to the satisfaction of all spectators it resisted the ele- ment nobly, and merely charred the wooden struc- ture without producing a life fire ; and from that time the water ^lass was introduced in Germany. A few years later the same liquid was introduced in the manufacturing districts of England as a substitute for cow’s dung by the cotton mills, and was called ‘‘ Dung- ing Salt.” The author having studied with Doebereiner, a professor of practical chemistry in Jena, was engaged goLtJBLi: GLASS. 15 In experiments on water glass, and who proposed an alteration in its composition, such as the compound of potash and soda, or 72 parts of carbonate of potash, 854 parts of carbonate of soda, and 152 parts of linelj pulverized quartz, which proved to be a better sub- stance, conceived the idea that water glass may be prolitably employed in this country for many purposes. In company with ship captains and builders he offered to substitute it in coppering vessels, which is attended with that expensive metal, the copper sheathing, and undertook to prepare the ship’s timbers in such a manner that the cells of the wood could be filled up with Silica, or, in other words, to silicify 'them, and produce a petrification of the organic substance, all of which at a very inconsiderable expense; in the Brook- lyn Navy Yard, he was permitted by the Ordnance Department, under the direction of Commodore Berry, then the Captain of the Yard, to perform the experiments with the spiles on the various docks, which were destroyed by the worms {Teredo navalis) so fast that they had to be replaced every three years. Also t1ie cannon balls exposed to the weather, becom- ing rusty and worthless in a few years, were varnished with his own preparation, and the addition of asphal- turn, and his experiments proved highly satisfactory, as in both instances of applications many years after- wards indicated their preservation. The water glass was neglected for many years ex« cept by the military authorities in Prussia, and we hear that the soldiers werfe instructed to wash their linen, and the State Prison at Spandau introduced it for washing the prisoners’ under garments ; and it was proved so economical, that one gallon of concentrated 16 SOLtJBLS GLASS. liquid was sufficient for washing 1,000 pieces. The soap manufacturers began to use it in England for producing a cheap soap. Liebig devoted, in the year 1850, much attention to the subject, and at the same time Kuhlmann introduced it as a new paint under the name of stereochromic painting, for ornamenting the interior of houses. He applied the fluid silicate of potassa, obtained by dissolving flints in caustic alkali, with the aid of water of a very high temperature, to harden chalk and porous stone; for he observed that on soaking chalk with this fluid silicate, a change took place: part of the chalk, combining with the silicic acid of the silicate of potash, becoming con* verted into silico carbonate of lime, the carbonic acid, thus free, combined with the potash, in time, particu* larly when assisted by heat- and dry air, the coating of silico carbonate was found to pass into a true com- pact deposit of silica, hard enough to scratch glass. The solution of silicate of potash could be applied either with a brush or a syringe, the surface being first cleaned and scraped. Three applications were considered sufficient. Although successful in the la- boratory, this method failed when applied to build- ings, because a dry atmosphere is needed during the whole period of hardening. Hot long after this sug- gestion had been made by Kuhlmann, the English manufacturer, Kansorne, of Ipswich, engaged in the manufacture of silicate of soda, following up the above experiments, attempted to fix the solution, when ab- sorbed with the stone, to produce a double decompo- sition by absorbing another solution, thus leaving an insoluble deposit within the substance of the absorb- ent stones on which it was desired to act. He found SOLUBLE GLASS. 17 that, bj a weak acid soliiHou, he could set free tlie silica, but in that state the deposited mineral had no coliesion. Following up, however, the application of the fluid silicate by a small portion of chloride of cal- cium, (a waste product from the salines and acetic acid manufacturers,) it resulted that the chlorine, parting from the calcium, attacked the soda of the silicate, forming common salt, which is easily dissolved away, while the silicic acid, set free, combining with the lime, formed with it silicate of lime. This mineral is nearly insoluble, very hard, and adheres with great tenacity to foreign substances, as is illustrated in com- mon mortar. Silicate of lime thus formed resists car- bonic acid and dilute sulphuric acid, and is little afiected by any of the common alkalies or ammonia. The effect of this treatment on stones that have not already been inserted into buildings has Teen very favorable ; and they appear to have stood without de- cay under exposures sufficient to have produced much injury on the same stone unprotected and applied on a large scale to buildings that have already shown symptoms of decay, the result is less satisfactory ; but years must elapse before a very decided opinion can be given on the process. After some time we will be able to see the result in the Houses of Parliament and Westminster Abbey, where the magnesian limestone has been treated by this process. A combination of Kuhlmann’s process wdth a tem- porary wash of some bituminous substance has been tried on a large scale in the Speaker’s Court of the Houses of Parliament, by Szereling, which will like- wise be decided after some time upon its superiority. The manufacture of the water glass or soluble sili- 18 SOLUBLE GLASS. ^cate, or soluble glass, has only been known since our present time, although the various kinds of glass, imi- tation of gems, belongs to antiquity ; for Pliny states that glass was first discovered by accident in Syria, at the mouth of the River Belus, by certain merchants driven thither by the fortune of the sea, and obliged to continue there and dress their victuals by making a fire on the ground, where there being a great store of the herb 'kali^ that plant burning to ashes, its salts, mixed and incorporated with sand or stones fit to vitrify or make glass.” The word kali was explained by Boerhave as one of the materials of glass, salt and sand / the salt here used is procured from a sort of ashes, brought from the Levant, called polverine or rochetta, which ashes are those of a sort of water plant called kali, of the species of that found in some parts of England, called frog-grass, or crab-grass, cut down in summer, dried in the sun, and burnt in heaps, either on the ground or on iron grates, the ashes falling into a pit, grow into a hard mass or stone, fit for use.” This material evidently means the kelp, which was burnt and converted into Barilla. It is also certain that Kunkel, in 1679, states that the art of glass was already brought to its highest perfection, and expressed that Neri, in his treatise “ De Arte Yitraria,” has communicated complete knowledge of artificial gems. Much is said of flexible glass not rotting, of a fusible or soluble glass, of wdiich Yan Helmont, the chemist of the first part of the seventeenth century, knew nothing. The improvements in the manufacture of the soluble glass, particularly that of soda, were of great importance. He had, in the first place, dis- carded the sand, which he did not find compact SOLUBLE GLASS. 19 enongh for producing a good paint, and substituted the flints, found in the chalk : this species of silex he exposes under a pressure of 7-8 atmospheres, in an iron cauldron, to a hot soda lye standing 38°, which process was patented by the brothers S*iemens, in the year 1845, with this difierence, that they produce a liquid at a very high temperature corresponding in vapors of 4-5 atmospheres, by which process they ob- tain 3-4 times the quantity of silica to a thin liquid. Liebig proposes the employment of the infusorial earth, which dissolves readily the caustic soda lye, whereby he obtains 240 parts of silica jelly from 120 parts infusorial earth, and 75 parts soda ash. It is well known that the infusorial earth is pretty pure silica of 87 per cent, and 8 per cent, water. The beds of Bilin, in Bohemia, and belonging to the fresh water Tertiary, have a thickness of 14 feet, also in Planitz, in Saxony. Ehrenberg estimates that about 18,000 cubic feet of the siliceous organisms are annually formed in the harbor of Wismar, in the Baltic Sea ; the deposit of infusorial earth in Richmond, Ya., con- tains over lUO species, and forms a thick stratum. SIL'EX, OR SILICA. This substance is an oxide of siliciiim, and being the main body of our preparation, deserves a full and detailed description. Silicium is the metallic basis of silica, or silex, and is equally abundant with oxygen as a constituent of tlie solid surface of the globe, also constituting a large portion of aerolites, from the region of space. This metallic base was discovered by Berzelius, in 1823, and is obtained artificially in the following manner : Well dried silico fluoride of potassium, 10 parts, are mixed with 8 or 9 parts potassium in an iron or glass tube, and the potassium fused and stirred with the salt by an iron wire. It is then heated by a spirit lamp, when it suddenly becomes ignited from the reduction of silica by the potassium forming a brown mixture of fluoride and siliciuret of potassium. It is thrown in cold water, when hydrogen is evolved, the potassium of the silica not being oxydized by water and the sili- cium separating. When the effervescence has ceased, the solution is poured off, fresh cold water added and poured off, until it ceases to be alkaline, when boiling water is used to wash the silicium as long as it extracts any thing. Silicium is inflammable in the air, by heat, about one-third burning to silica, which, removed by fluo- hydric acid, leaves a dark, chocolate, brown powder, heavier than oil of vitriol, is combustible either in the 21 BILEX, OR SILICA. air or oxj^gen, or even when gently ignited with salt- petre. Silica, or oxide of siliciiim, is synonymous wnth silicic acid, silex and pure sand, or quartz, in its vari- ous forms and appearances, and constitutes a very large proportion of the solid crust of the globe ; is the prin- cipal constituent of all simple minerals, and forms a greater variety of salts than any other acid. It is easily prepared pure from powdered quartz, sand, fel- spar, or other silicious minerals, by fusing them with four times their weight of a mixture of carbonate of potassa and soda, or by either carbonate alone, dis- solving them in dilute muriatic acid, filtering and evaporating the solution to dryness by a gentle lieat, digesting in muriatic acid, filtering and washing with hot water. This silica has two modifications, the one soluble in water and acids, the other insoluble. The soluble is that obtained in the above process for preparing silica, and is always formed by fusing silicates with alkalies, but may also be formed by boiling fine Silex with strong alkaline solutions. It is soluble in water and acids, and when the solu- tions are concentrated it usually separates as a jelly, [gelatinous silica,] and when evaporated to dryness, passes into the insoluble modification. Silica is a white, gritty powder, insoluble in water and acids, infusible in the highest heat of our furnaces, but fusible in a stream of oxygen driven through an alcohol flame. It fuses in this case to a clear glass, which may be drawn out into flexible threads. When the fused bead is drop]>ed in water, it becomes so hard as to indent a steel pestle and mortar. It is the fee- 2 * 22 SILEX, OE SILICA. blest acid at common temperatures, but by a high beat can expel all volatile acids. Quartz is found in nature crystalized in a great variety of forms, the rhombohedral prevailing, and for the most part hemiliedral to the rhombohedron, or tetrahedral to the hexagonal prism. The annexed two figures give some idea of its occurrence : The cleavage is very indistinct, sometimes efiected by plunging a heated crystal in cold water. The crystals are either very short or very much elongated, sometimes fine acicular usually implanted by one ex- tremity of the prism, occasionally twisted or bent. The prismatic faces commonly striated horizontally, and thus distinguishable, in distorted crystals from the pyramid. Crystals often grouped by juxtaposition, not proper twins, frequently in radiated masses with a surface of pyramids, or in druses having a surface of pyramids or short crystals. Herkimer and Ulster counties, of the State of Hew-York, produce quartz crystals of the most complicated forms, which occur from the size of a pin’s head to that of a foot. Quartz is also found massive, from the coarse or fine granular to fiint-like or crypto-crystaline ; sometimes mammil- lary stalactitic, and in concretionary forms. i i SILEX, OR SILICA. 23 Quartz has a hardness, 7, and a specific gravity of 2.65 ; a vitreous lustre sometimes inclining to resinous ; splendent and nearly dull ; is colorless when pure, but often having various shades of yellow, red, brown, green, blue and black. The streak is white of pure varieties ; of impure often the same a§ the colors, but much paler. Quartz is transparent and opaque ; its fracture is perfect conchoidal and subchonchoidal, is tough, brittle and friable. The polarization of quartz is circular, there being a colored centre instead of a central cross, and the rings of color around enlarging as the analyzer is turned to the right in right-handed crystals, or left, in left-handed, and colored spirals are seen, which rotate to the right or left when the.incident light and emerged light are polarized, one circularly, and the other plane. Pure silica, which has the symbol of Si, consists of 53.33 parts oxygen, and 46.67 silicon=100. It is un- altered if brought alone before the blow-pipe, but with soda it dissolves with effervescence ; it is unacted upon by any salt of phosphorus ; it is only soluble in fluohydric acid. There are two varieties of quartz in existence : I. The crystalized, or phenocrystaline, w’hich is vitreous in lustre. II. The fluid-like, massive, or crypto-crystaline. The first division includes all ordinary vitreous quartz, whether having crystaline faces or not ; while the second variety has been acted upon somewhat more by 'attrition and chemical agents, as fluoric acid, than those of the first. 24 SILEX, OR SILICA. I. The following species of quartz belong to the phe- nocrjstaline, or vitreous varieties : 1. The ordinary crjstalized quartz, rock crystal, which is the colorless quartz, or nearly so, whether in distinct crystals or not. a. The regular crystals, or limpid quartz. h. The right-handed crystals. c. Left-handed crystals. d. Cavernous crystals, having deep cavities par- allel to the faces, occasioned by the interfer- ence of impurities during their formation. e. Cap quartz, made up of separable layers or caps, owing to the deposit of a little clayey material at intervals in the progress of the crystal. f. Drusy quartz, a crust of small or minute quartz crystals. g. Radiated quartz, often separable into radiated parts, having pyramidal terminations. h. Fibrous, rarely delicately so, from Cape of Good Hope. 2. Asteriated quartz, star quartz, containing within the crystal whitish or colored radiations along the di- ametral planes. Part, if not all, asteriated quartz is asteriated in polarization, as already remarked. 3. Amethystine quartz, amethyst, clear, purple or blueish- violet ; the colbr is supposed to be due to manganese; the shade of violet is usually deepest pa- rallel to the planes R. 4. Rose, rose red or pink quartz. It becomes paler on exposure, commpn, massive; and then usually 25 SILEX, OR SILICA. much cracked, lustre sometimes a little greasy. The action is, according to Fuchs, due to titanic acid ; the general impression is, however, that its color is owing to manganese. 5. Yellow, false topaz, yellow and pellucid, or nearly so, resembling somewhat yellow topaz ; but very different in crystalization, and in absence of cleavage. 6. Smoky quartz ; the Cairngorm stone. It is smoky yellow to smoky brown, and often transparent, but varying to brownish black, and then nearly opaque, in thick crystals. The color is probably due to titanic acids, as crystals containing rutile are usu- ally smoky. It is called Cairngorm, from the locality in Scotland. 7. Milky, milk white, and nearly opaque; lustre often greasy, called then greasy quartz. 8. Siderite, or sapphire quartz, of indigo, or Berlin blue colors. A variety of quartz occurring in an im- pure limestone at Colling, in Salzburg. 9. Sagenitic, containing within acicular crystals of other minerals : these acicular crystals may be rutile, or black Tourmaline, or Goethite, stilbite, asbestos, actinolite, hornblende, or epidote. 10. CaCs eye, exhibiting opalescence, but without prismatic colors, especially when cut in cabochon, an effect due to fibres of asbestos. 11. Aventurine quartz, spangled with scales of mica or other mineral. 12. Impure quartz, from the presence of distinct minerals distributed densely through the mass, such as ferruginous, either red or yellow oxide of iron, 26 SILEXj OR SILICA. chloritic from ^chlorite, actinolitic, micaceous, arena- ceous owing to sand. Quartz crystals also occur penetrated by various minerals, as topaz, corundum, cbrysoberyl, garnet, different species of hornblende and Pyroxene groups, kyanite, zeolites, calcite and of rutile, stilbite, hema- tite, Goetliite, magnetite, fluorite, gold, silver, anthra- cite, &v,. As quartz has been crystalized through the aid of hot waters or of steam in all ages down to the present, and is the most common ingredient of’ rocks, there is good reason Avhy it should thus be found the enveloper of other crystals. . 13. Quartz containing liquids in cavities. These liquids are seen to move with the change of position of the crystal, provided an air bubble be present in the cavity ; they may be detected also by the refrac- tion of light ; the liquid is either pure water, or a mineral solution, or petroleum-like liquid, II. The crypto-crystaline varieties of quartz are the following : 1. Chalcedony ; it has the lustre nearly of wax, and is either transparent or translucent ; the color is white grayish, pale brown to dark brown, black, tendon color common, sometimes delicate blue ; also of other shades, and then having other names ; it is often mammillary, botryoidal, stalactitic, and occurring lin- ing or tilling cavities in rocks. 2. Carnelian ; a clear red chalcedony, pale to deep in shade, also brownish red to brown ; the latter called sardonyx, reddish brown by transmitted light. 3. Chrysoprase ; an apple green chalcedony ; the color is due to the presence of oxide of nickel. 27 SILEX, OR SILICA. 4. Prase ; translucent and dull leek green ; taking its name from the Greek a leek. 6. Plasma ; a rather bright green to leek green, and sometimes nearly emerald green color, and sub-trans- lucent or feebly translucent, sometimes dotted with white. Heliotrope, or bloodstone, is the same stone essen- tially, with small spots of red jasper, looking like drops of blood. The jasper of the ancients- was a semi-transparent or translucent stone, and included, in Pliny’s time, all bright colored chalcedonj^ excepting the carne- lian ; the same author gives special prominence to sky blue and green, and mentions also a shade of purple, a rose color, the color of the morning sky in autumn ; sea green, serpentine color, (yellow, like serpentine,) smoke color, but in general there is a tinge of blue, whatever the shade. 6. Agate; a variegated chalcedony; the colors are either banded or in clouds, or due to visible impu- rities. (Banded agate.) where the bands form delicate parallel lines of white, tendonlike, waxlike, pale and dark brown and black colors, and sometimes bluish and other shades, they follow waving or zigzag courses, and are occasionally concentric circular, as in the eye agate. The tine translucent agates graduate into coarse and opaque kinds. The bands are the edges of layers of deposition, the agate having been formed by a deposit of silica, from solutions intermit- tently supplied in irregular cavities in rocks, and de- riving their concentric waving courses from the irreg- ularities of the walls of the cavity. As the cavity can- 28 8ILEX, OB 8ILI0A. not contain enough of the solution to fill it with silica, an open hole has been supposed to be retained on one side to permit the continued supply, but it is more probable that it passes through the outer layers by osmosis, the denser solution outside thus supplying silica as fast as it is deposited within. The colors are due to traces of organic matter, or oxides of iron, manganese, or titanium, and to differences in rate of deposition. The layers differ in porosity, and there- fore in the rate at which they are etched by fluoric acid, the etching process brings out the different lay- ers, and makes engravings that will print exact pic- tures of the agate. Owing also to the unequal po- rosity, agates may be varied in color by artificial means. Irregularly clouded agate, the colors various, as in banded agate. A whitish, clouded variety, which Pliny has de- scribed and given fully the characters. Colored agate, due to visible impurities ; a moss agate, or mocha stone, filled with brown moss-like or dentritic forms, distributed through the mass of den- tritic agate, containing brown or black dentritic mark- ings. These two have been fully described by Pliny as dentrachates. There are also eight agatized woods, wood petrified with clouded agate. 7. Onyx, like agate, in consisting of layers of dif- ferent colors, but the layers are in even planes, and the banding therefore straight, and hence its use for cameos, the head being cut in color, and another serv- ing as the background. T^he colors of the best are perfectly well defined, 29 STLEX, OR BILICA. and white and black, or white, brown and black al- ternate. 8. Sardonyx, like onyx in structure, but includes layers of carnelian, along with others of white, or whitish and brown, and sometimes black colors. 9. Agate jasper. An agate consisting of jasper, with veinings and cloudings of chalcedony. 10. Siliceous sinter. Irregular cellular quartz, formed by deposition from waters containing silica, or soluble silicates in solution. 11. Flint. ' Somewhat allied to chalcedony, but more opaque and of all colors, usually gray, smoky brown and brownish black. The exterior is often whitish, from mixture with lime or chalk, in which it is imbedded. Lustre barely glistening, sub vitre- ous; breaks with a deeply conchoidal fracture and a sharp cutting edge. The flint of the chalk formation consists largely of the remains of infusoria, sponges, and other marine productions. This mineral con- tains, according to Fuchs, partly soluble silica. 12. Hornstone. It resembles flint, is more brittle, and fracture more splintry. Chert is a term often applied to hornstone, and to any impure flinty rock, including the jaspers. 13. Easanite, Ij^dian stone, or touchstone. A vel- vet black siliceous stone or flinty jasper, used on ac- count of its hardness and black color for trying the purity of the precious metals. The color left on the stone after rubbing the metal across it indicates to the experienced eye the amount of alloy. It is not splintry like the hornstone : it passes into a compact, flssile, siliceous or flinty rock, of grayish or other col- 30 SILEX, OR SILICA. ors, called siliceous slate, and resembles ordinary jas- per, of various shades. 14. Jasper. An impure opaque colored quartz.] a. The reducing to hematite, or sesquioxide of iron. h. The yellow or brown, colored by the hj^drous sesquioxide of iron, and becoming red when so heated as to drive off the water. c. The dark green and brownish green. d. The grayish blue. e. Blackish or brown black. f. Striped or ribbon jasper, having the colors in broad stripes. g. Egyptian jasper in nodules, which are zoned in brown and yellow colors. Porcelain jasper is nothing but a baked clay, and differs from true jasper in being fusible on the edges before the blowpipe. Bed porphyry, or its base, re- sembles jasper, but is also fusible on the edges, being usually an impure felspar. Quartz is also found in the following forms : 1. Granular quartz, or quartz rock, which consists of quartz grains very firmly compacted, the grains often hardly distinct. 2. Quartzose sandstone. 3. Quartz-conglomerate. A rock made of pebbles of quartz with sand. The pebbles are sometimes jasper or chalcedony, and make a beautiful stone when polished. 4. Itacolumite, or flexible sandstone. A friable sand rock, consisting mainly of quartz sand, but con- SILEX, OR SILICA. 31 taining a little talc, and possessing a degree of flexi- bility when in thin laminae. 5. Euhrstone. A cellular flinty rock, having the nature in part of coarse chalcedony. 6. Pseudomorphous quartz. Quartz appears also under the forms of many of the mineral species, which it has taken through either the alteration or replacement of crystals of those species. The most common quartz pseudomorphs are those of cal cite, baryta, fluorite and siderite. Tabular quartz, Hay- torite, Beckite, Babel quartz, silicified shells and silicifled wood are found pseudomorphized by other minerals, either of carbonate lime, Datholite, fluor- spar, shells and wood. The texture of the wood, for instance, is well retained, it having been formed by the deposit of silica, from its solution in the cells of the wood, and Anally taking the place of the walls of the cells as the wood itself disappeared. Dissolved quartz, or liquid silica, occurs often in heated natural waters, as those of the Geysers of Ice- land, New-Zealand and California, mostly as a soluble alkaline silicate. Quartz is one of the essential constituents of granite, sienite, gneiss, mica, schist and many related rocks. As the principal constituent of quartz rock and many sandstones ; as an essential ingredient in some trachyte porphyry, &c. ; as the veinstone in various rocks, and for a large part of mineral veins ; as a foreign mineral in the cavities of trap, basalt and related rocks, some limestones, &c., making geodes of crystals or of chal- cedony, agate, carnelian, &c., as imbedded nodules or masses in various limestones containing the flint of the chalk formation, the hornstone of other limestones ; SILEX, OR SILICA. 82 these nodules becoming sometimes layers or masses of jasper occasionally in limestone. It is the principal material of the pebbles of gravel beds and of the sands of the seashore and river sandbeds. Independent of the quartz proper, as has been just described, nature produces a vast many minerals composed either solely of silica, with slight variations in their degree of hardness or specific gravity, such as the following: The opal, which is subdivided, in 1. The precious opal^ exhibiting a play of delicate colors. 2. The fire op>dl, of hyacinth red to" honey-yellow colors. 3. The girasol^ of bluish white color, with reddish reflections in a bright light. 4. The common opal^ in part translucent, and milk- white to greenish, yellowish, bluish. Resin opal, wax or honey color, with resinous lustre. Olive green opal ; brick-red opal ; hydrophane, a translucent opal, whitish or light colored, adheres to the tongue, and becomes more translucent or transparent in water, wherefore its name. An orange, yellow opal, called Forcherte ; it is colored by orpiment. 6. Cachelong, Opaque and bluish white, porcelain white ; often adheres to the tongue. 6. Opal agate. Agatelike in structure, but consist- ing of opal of difierent shades of color. T. Menilite. In concretionary forms, tuberose, reniform ; opaque, dull gray and grayish brown. 8, Jaspopal. An opal, containing some yellow oxide of iron, and having the color of yellow jasper. BlLEX, OR SILICA. 33 9. Wood opal. Wood petrified bj opal. 10. Hyalite. Clear as glass and colorless, consti- tuting globular concretions and crusts. 11. Fioidte^ or siliceous sinter ; also called pearl sinter, from Santa Fiora, in Italy, and other volcanic rocks, formed from the decomposition of the siliceous minerals of volcanic rocks, or from the siliceous waters of hot springs. 12. Float stone j also called swimming quartz ; is light, concretionary or tuberose masses, white or grayish, sometimes cavernous. 13. Tripolite. Infusorial earth ; formed from the siliceous shells of diatomous and other microscopic species, occurring in deposits often miles in area, either uncompacted or moderately hard. a. Infusorial earthy or earthly tripolite, is a very fine grained earth, looking often like an earthy chalk or clay ; but harsh to the feel, and scratching glass, when rubbed on it. h. Bandanite / a kaolin-like variety from France. G. Tripoli slate. A slaty or thin laminated va- riety ; fragile, often mixed with clay, mag- nesia and oxide of iron. d. Alumocalcite. A milk-white material, very light, having a hardness of only 1 to IJ, and a sp. gr. of 2.171, and probably a variety of tripolite. This mineral is, probably, the most economical and useful material for the manufacture of the soluble glass. The opal family is likewise a quartz, but a little softer and contains some water, is soluble in a heated solution of potash, while quartz is not. u on SILICA. In England and France the flints from the chalk are mostly employed in the manufacture of soluble glass ; but in the United States clear sand, from the river- bed of New-Jersey and Mississippi rivers, are solely used in its manufacture. Sand generally consists of particles of quartz, but there is also a granitic sand, containing particles of felspar as well as quartz, where it has not been long enough exposed to meteoric agents to decompose the felspar. Sand Usually consists of grains more or less rounded, but sometimes angular, and then preferable for mortar. There are several varieties of the sandstone, such as micaceous^ argilla- ceous^ marly and flexible. Common sand is mainly comminuted quartz. Gravel is a mixture of sand wflth pebbles. Volcanic sand is sand of volcanic origin ; either the cinders or ashes, or comminuted lava. Alluvial sand is the earth deposited by run- ning streams, especially during times of flood ; it con- stitutes the flats on either side of the stream, and is usually in thin layers, varying in fineness or coarse- ness, being the result of successive depositions. In order to use the sand for the manufacture of soluble glass, which shall equal that manufactured from flint, or infusorial or siliceous earth, it is best to digest the sand with chlorohydric acid, which is capable of dis- solving all the foreign substances, and then by frequent washings and dryings in the sun, produces a pretty pure silica. Iron, clay, lime, which are, more or less, found in the mud, may easily be detected by the vari- ous chemical tests, such as by ammonia, the iron ; by oxalate of ammonia, the lime ; and clay, by carbonate of soda. If the pure crystalized quartz, flint or hornstone sileX, on siLidA. glioiild be used for the manufacture, the same must be reduced into coarse or granular condition, which is effected by calcining the mineral, and when red hot, cold water is thrown over it, whereby it becomes dis- ^ integrated and falls to pieces, and it is then ground in mills used by the glass manufacturers. Before closing the chapter of silica, it must be stated that nature has given us a vast variety of silicates ; that the alkaline silicates of soda, potash and lime, which are called the soluble silicates, are spread over the globe in such quantities, like oxygen compounds, with the addition of many other bases in nature, that there are very few mineral substances known in which silica, representing the acid, is not combined with the various elements, and forming silicates which are again divided in anhydrous and hydrous silicates, all of them having ternary oxygen compounds. The anhydrous silicates are again subdivided, as 1. Bisilicates / 2. Unisilicates and 3. Suh- silica, tes ; while the hydrous silicates are again divided in various sections. The whole crust of the globe consists in silicates. The felspar mica is a pure silicate. We have a soda fel- spar, and a potash felspar, and a lime felspar, while the mica is a compound of silica combined with some other bases, such as alumina, magnesia, &c. The zeolites form a large class of silicates, which resemble the felspar, but contain water, and are less hard and more fusible, such as the analcime, chabasite, stilbite, heulandite, &c. THE ALKALIES, &c. In the manufacture of soluble glass, the alkalies are, in importance, next to the quartz or silica, such 36 SILEX, OR SILICA. as the soda and potash, both of which are employed as the carbonates, which ought to be pure. The carbonate of potash, which is the pearlash, must be free from foreign saline substances. The glass manufacturers prepare that material by washing it freely with water and evaporating the solution to the formation of a precipitate of salt, and then the water is run off. The Soda emploj^ed in the manufacture is the soda ash of comitierce, and is never pure enough, contain- ing water and other salts, which ought to be removed from it by dissolving, crystalizing, and then calcina- tion of the crystals. Suljphate of soda^ or Glauber salt, has been used by some manufacturers in place of soda ash, which ought not to be employed, as the same is partly converted into sulphide or sulphuret and oxsulphite of sodium, which is detrimental. Fluorspar, a fluoride of calcium, may be added to the mixture of sand and alkali, as it produces a more fusible silicate, which will harden soon after applica- tion by the affinity for this alkali. In the production of hard cements, the fluohydric acid is of great service, for it assists in the hardening of the mortar, and form- ing a good, permanent cement. White arsenic in powder, [arsenious acid,] and nitrate of soda, are used in this composition ; they produce a white soluble glass ; while, without any admixture, the product is green. From three to eight per cent, of either is used. THE MANUFACTURE OF SOLUBLE GLASS. I. The POTASH SOLUBLE GLASS. It is obtained by mixing 15 parts powdered quartz or pure sand with 10 parts purified pearl ashes, and 1 part charcoal, in a Hessian crucible, and exposing the mixture so long to a heat until the mass after six hours has become vitrified. Charcoal is employed for assisting, by its decomposition, the production of car- bonic acid, as also some sulphuric acid which may have been produced. It is at present, however, omit- ted, and if manufactured on a large scale the vitrifi- cation is done rn a reverberatory furnace capable of holding from 1,200 to 1,500 pounds. The ashes and sand must be Avell mixed together for some time, and the furnace must be very hot before throwing the mix- ture in it, and must be constantly kept up until the entire mass is in a liquid condition.. The tough mass is then raked out and thrown upon a stone hearth and left to cool. The glass mass so obtained appears to be hard and blistery, of blackish gray color, and if the ashes w^ere not quite pure it will also be adulterated with foreign salts. By pulverizing and exposing it to the air it will absorb alkali, and by degrees the foreign salts will, after frequent agitation and stirring, be completely separated, particularly after pouring over the mass some cold water, which dissolves them, but not the soluble glass. The purified mass is now put into an iron cauldron, containing five times the quan- 38 MANUFACTURE OF SOLUBLE GLASS. tity of hot water, in small portions, and with constant agitation, and replacing occasionally hot water for that which evaporated during the boiling, and after five or six hours the entire mass is dissolved ; the liquid is removed and left to settle over night, in order to be able to separate any un decomposed si lex. The next day it is evaporated still more, until it has assumed the consistency of a syrup, and standing 28° B., and is composed of 28 per cent, potash, 62 per cent, silica and 12 per cent, water. It has an alkaline taste, and is soluble in all proportions of water, and is precipitated by alcohol, and if any salts do effervesce they may be wiped ofP. The color is not quite white, but assumes a greenish or yellowish, white color. JI. The MANUFACTURE OF SODA SOLUBLE GLASS : To 45 parts silica or white river sand are added 23 parts carbonate of soda fully calcined, and 3 parts charcoal, and is then treated in the same manner as the other glass. The proportions of the mixture are altered by the different manufacturers ; some propose to 100 parts silex, 60 parts anhydrous glauber salt and 15 to 20 parts charcoal. By the addition of some copper scales to the mixture, the sulphur will be separated. Another method is proposed by dissolving the fine silex in caus- tic soda Ij^e. Kuhlmann employs the powdered flint, which is dissolved in an iron cauldron under a pres- sure of 7 to 8 atmospheres. According to Liebig the infusorial earth is recommended in place of sand, on account of being readily soluble in caustic lye, and he proposes to use 120 parts infusorial earth to 75 parts caustic soda, from which 240 parts silica jelly rnaj^ be obtained. His mode is to calcine the earth so as to become of white colors, and passing it through sieves. MANUFACTURE OF SOLUBLE GLASS. 30 The lye he prepares from 75 ounces calcined soda, dissolved in five times the quantity of boiling water, and then treated by 56 ounces of dry slacked lime; this lye is concentrated by boiling down to 48° B. ; in this boiling lye 120 ounces of the prepared infu- sorial earth are added degrees, and very readily dissolved, leaving scarcely any sediment. It has then to undergo several operations for making it suitable for use, such as treating again with lime water, boil- ing it, and separating any precipitate formed thereby, which, b}^ continued boiling, forms into balls, and which can then be separated from the liquid. This clear liquid is then evaporated to consistency of syrup, forms a jelly slightly colored, feels dry and not sticky, and is easily soluble in boiling w^ater. The difference between potash and soda soluble glass is not material ; the first may be preferred in white washing wdth ])laster of Paris, while the soda glass is more fluidl}^ divisible. It may be observed, that before applying either soluble o’lass, it ought to be exposed to the air for ten to twelve days, in order to allow an efflorescence of any excess of alkali, which might act injuriously. There are, however, many methods proposed to ob- viate this difficulty, and which will be mentioned hereafter. III. The DOUBLE SOLUBLE GLASS. This is a compound of potash and soda, is prepared from 100 parts quartz, 28 parts purified pearl ashes, 22 parts anhydrous bicarbonate of soda, 6 parts of charcoal, which are spread in such manner as already described. If the mass is fully evaporated to dryness, forms a vitreous solid glass which cannot be scratched 40 MANUFACTURE OF SOLUBLE GLASS. by steel, has a conchoidal fracture, of sea-green color, translucent and even transparent, has a specific gravity of 1.43. lY. The SOLUBLE glass, after Kaulbach, for the use of sterro-chromic painting. It is obtained by fusing 3 parts of pure carbonate of soda and 2 parts powdered quartz, from which a con- centrated solution is prepared, and 1 part of which is then added to 4 parts of a concentrated and fully saturated solution of potash glass solution, by which it assumes a more condensed amount of silica with the alkalies ; and which solution has been found to work well for paint. Siemens’ patent for the manufacture of soluble glass consists in the production of a liquid quartz^ by digesting the sand or quartz in a steam boiler tightly closed, and at a temperature correspond- ing to 4-5 atmospheres, with the common caustic alkalies, wdiich are hereby capacitated to dissolve from three to four times the weight of silica to a thin liquid. The apparatus, which was patented in 1845, is well known in this country ; as some persons, many years later, obtained a patent for the same apparatus in the United States, which on inspection does not difler from that of Siemens Brothers. Description of Siemens’ Apparatus for dissolving silica in soda lye, under a pressure of five atmos- pheres, or sixty pounds to the square inch : APPARATUS FOR DISSOLVING QUARTZ, TINDER PRESSURE OF FIVE ATMOSPHERES. H.E.P EASESC ^fANIJFACTURE OF SOI.UBLE GLASS. 43 The whole apparatus consists of the boiler A and the clissolvino; kettle B. Fig. 1 represents the front side, and 2 the horizon- tal. A and B are connected by the pipe a. The kettle B is constructed of two strong walls, with a space h of the width of 1-2 inches. The steam passes through the pipe a into the space h. In order to reach the inner kettle, which is per- fectly tight, the wall c has to be unscrewed. Under the middle of this wall the box d is now attached, which encloses the iron pipe passing through the length of the kettle. Then the shovels, or agitators, ff^ are now applied with the wheel g at the end for effecting the revolutionary movement. The steam- cocks A, as seen at the front wall (?, for indicating the stage of the water in the interior kettle ; the cock i serves for pumping and discharging the solution, and the cock h for letting off the water, which was con- densed in the steam chamber C. The outer kettle is surrounded with ashes, or any other non-conducting substance. The boiler is supplied with ventils and manome- ters, and the kettle B. is tested to stand a pressure of 80-100 pounds per square inch. The kettle is now filled with the necessary quantity of silex, after the front wall has been screwed on by means of the cock and is filled up with the caustic lye, wdiich is composed of 100 lbs. carbonate of soda to 20 gallons water, and 1 lb. of silex for each quart of water; wdien filled, and the steam having assumed the tension of 60 lbs. to the square inch, as indicated by the safety ventil, the cock m is opened, when the steam passes to the other kettle, and condenses on the 44 MANUFACTURE OF SOLUBLE GLASS. cold wall of the inner kettle ; here the temperature is raised, and assumes soon a pressure of sixtj^ pounds, which point is indicated hj the escape of steam from the safety valve. Fire is now kept up for six to eight hours under a constant escape of vapor. During all this time the shovels or agitators are kept in motion by the workmen, and tlien the silex contained in the kettle will have dissolved from 80-90 per cent., and is drawn off, and may be re-filled for a new operation. The apparatus may undergo some modification as the agitators get a different form, etc., etc. The silica to be employed is, as already stated to be, the common sand, which is at first calcined and thrown in water; when dry, it is ground as fine as flour. The liquid silica when discharged from the kettle may be evaporated to dryness, when it assumes a compact mass, a vitreous and conchoi-dal fracture and a hardness, so as to give sparks on steel, without the brittleness of flint. The solution as it is obtained from the kettle may be converted into a white fine stone, by adding fine sand, until it assumes a plastic mass, say 3-4 parts, with the addition of a little chalk or lime and white clay ; by exposing this mass when formed into pressed stones or objects to the atmosphere for some time, the stone is now in the best condition. Instead of fine sand, fine powdered dry silicate may be substituted, and a better stone thereby obtained. When the mass is dried, it must undergo the pres- sure of a hydraulic press. The addition of chloride of calcium and chloride of MANUFACTURE OF SOLUBLE GLASS. 45 iron, either in liquid state or in dry powders, is highly recommended for promoting the hardening process. Siemens’ remarks of the application of the silex liquid, that the sand to be employed must be first calcined and then thrown into cold water, and after- wards ground into fine powder, which, when mixed with his liquid, becomes compact, insoluble and white, possessing a vitreous and conchoidal fracture, and a hardness so as to give sparks by steel. The same gentleman also recommends for the pro- duction of a white stone, to work up the fine silex with so much liquid soluble glass so as to form a plastic mass, say from 3-4 parts of the sand may be required, similar to potter’s clay, and adding, at the same time, a small quantity of chalk and fine clay, whereby the mass becomes more uniform and com- pact. Prepared in this manner, objects moulded or pressed from the mass must be exposed to the air for some time. For monuments, millstones and other building ma- terial, he uses 1 part liquid silica to 2 parts fine sand and 12 parts coarse sand, which mass, formed into the desired sizes or objects, after being dried long enough in the air, are left in a heated room of 75° for several days, and even to the boiling point of water ; they become so hard, after a lapse of four to six days, that they never crack or fall to pieces. It is also recom- mended to expose the mass to the pressure of a hy- draulic press before exposing to the air. For obtain- ing a cement — roofing and wall body — it is advisable to add the chloride of calcium to the mass, and thereby the excess of alkali is absorbed. 3* 46 MANUFACTURE OF SOLUBLE GLASS. The mass so formed may be steeped in a solution of chloride of calcium, or chloride of iron, before exposing to the atmosphere. In all these cases the silica ought to be emploj^ed very concentrated, even in jelly form. Tim uses of the soluble glass are here condensed in a short sketch, intended as a circular to those desirous of obtaining some information : “the USES OF ^'SOLUBLE GLASS (lIQUID SILEX,) SILICATE OF SODA, SILICATE OF POTASH, SILICATE OF SODA AND POTASH (combined.) “ Liquid silica is now employed in the arts for many useful purposes, and particularly for preserv- ing stone buildings from decomposition ; for prepar- ing an artificial stone, and thereby reducing the price of building, and making a composition more orna- mental. Its introduction for architecture is but of recent date, and the true and proper method of appli- cation not yet on an infallible base ; but the subject is of so vast importance, that experiments are con- tinually going on for making a perfect stone from its original ingredients. “ The cause of gradual decomposition of building stone is attributed to the expansion and contraction of water absorbed, as well as to the chemical action of carbonic acid of the atmosphere, which abstracts portions of the gases from the silicates, and liberat- * In tlie year 1832 Dr. F.*prepared a quantity of soluble glass for tlie U. S. Government to preserve the cannon, guns and bomb-sliells from rust or oxydation at the Navy Yard in Brooklyn, to the fullest satisfaction of the late Commodore Perry. MANUFACTURE OF SOLUBLE GLASS. 47 ing thereby silica. Many palaces in Europe, churclies and other public buildings, have been retinished by the silicate, such as the Louvre and Notre Dame Ca- thedral in Paris, the Houses of Parliament in London, and in other cities. Still, its general application has met with many failures. It was found that rain counteracted the effect before the alkali has had time to take up a sufficient quantity of carbonic acid from the atmosphere and to liberate the insoluble silicate ; the coating will produce cracks, and a gradual disin- tegration of the surface or compound is caused there- by. Numerous remedies were suggested to counter- act this evil — the chloride of calcium, oxychloride of magnesium, the bittern of the salines, and hydroflu- oric acid. At present, a concrete stone of considera- ble hardness and durability is now prepared by means of greater pressure and proper manipulation, the main object being to neutralize and extract the alkali, and to form a solid chemical compound by a second aj)plication of a weak wash of chloride of calcium or magnesium. The object is now fully achieved. “ Another important application of the soluble glass is to render wood non-inflammable, and stop any communication of the Are, and at the same time proof against water and damp. The wood, timber or other substances, after being boiled for several hours in the soluble glass, then exposed in tanks, contain- ing solution of lime water and solutions of chloride calcium, are hereby petrified. “ Rail-road sleepers, cross-ties, house, ship and bridge timber will also be silicified by this process. Telegraph poles become more durable and better non- 48 MANUFACTURE OF SOLUBLE GLASS. conductors of electricity. The lining of barrels for oil and other liquids, the coating of tanks, tubs and cisterns, flour barrels, to prevent the flour getting musty, is very easily and efiectuall}^ done by the proper and judicious use of the liquid silica. “ Soluble glass may be mixed with paper pulp, or cheap vegetable and animal fibre, and serve for the manufacture of a variety of useful articles, such as boxes, trunks, soles for boots and shoes, patterns, moulds and handles. Invaluable and of the highest iisefulnessy the soluble glass can he employed in fire- proof paints ^ cements^ varnishes^ etc.^ for which pur- poses the daily demands are sufficient proof s. The dentists make use of the^silica for mending their plaster moulds, or in case of an accident to the cast of a set of teeth. Valuable documents are made fireproof, and parchment board, slates and marbles are cemented together, and cracks and crevices filled up. “ The woolgrowers apply the silicate of soda and potash to the greatest advantage for cleansing or de- greasing the fleece wool and make it soft. “ The waste of wool or cotton used in the locomo- tive engines to sustain the lubricating materials, may be cleaned and made new by the aid of soluble glass. A hard and ornamental cement, which can be moulded like plaster of Paris, is obtained from the mixture of silicate of soda and ground dolomite or magnesian limestone, which may be used both natural and calcined in equal quantities, and before the mass is dry, the bittern (chloride of magnesium) from the salines is added, which will harden it at once. A good cellar and roofing cement is made by adding to this mass three parts of white sand. MANUFACTURE OF SOLUBLE GLASS. 49 “ The silicate is also used for penetrating fire-brick and clay, in order to make them more fireproof, and also used for cementing the walls ; for producing a durable putty in iron castings, such as furnaces, heaters, stoves, etc., and also for mending air-holes. Boiler makers can produce a very durable lining by making a cement of silicate with asbestos and man- ganese finely ground ; it renders boilers and other metallic vessels perfectly fireproof, and tlie best fire and anti-rust paint for iron, steel and brass. There are a great many more useful applications in which the silicate may be used.” The alkaline silicates, as have been here described, have a bright future for their application : the genius of the nineteenth century cannot fail to accomplish the perfecting the work begun fifty years ago, and to this moment still liable to faults. Ere long we will be enabled to produce an artificial stone which shall excel nature; we will be able to produce a perfect silicification of wood and other organic matter ; we will challenge the atmosphere and other chemical productions to do their best for forming a decomposi- tion of those materials obtained by the new acquired skill to resist their action. The labors of Fuchs, Lie- big, Kuhlmann, Yicat, Fremy, Guerin and Bansome have fairly begun their work, and in ten years more the sliipbuilder, carpenter, mason, painter, the rail- road contractor and the mechanic in general, will consider this valuable substance indispensable. Among the most simple processes in the silicifica- tion or manufacture of artificial stone is that of Kan- some, which consists in the following manner : 50 MANUFACTURE OF SOLUBLE GLASS. The sand, after being dried, is worked up in a mill with the soluble silicate prepared from caustic soda and flints, the latter being dissolved bj the former, and evaporated down to a specific gravity of 1,700. The plastic mass thus produced is obedient to the will of the moulder, and can be manipulated into any form, from a cube to elaborate screens, from a grind- stone to an exceedingly chiseled fountain. The' mass so prepared is then saturated with chloride of calcium, applied simply by immersion or assisted by the action of an air-pump, in either process the so- lution being gradually heated to a temperature of 212° F. The indurating action of the chloride of calcium is promoted in closed chambers connected with a steam boiler. When this has been carried on for a sufficient length of time, by opening a cock the solu- ,tion is forced by steam pressure into a separate cham- ber, leaving the stone to cool gradually in partial vapor, by which all danger of cracking is avoided ; a casualty which is liable to happen when large masses are exposed to rapid extremes of temperature in the open air. In order to remove or extract the soluble salts of calcium and sodium from the body of the stone, which is effected in the same closed chambers by the admission of steam, or steam and water alternately, which, as it condenses and becomes saturated with the salts referred to, is returned into the boiler, where the steam is generated, and the chloride of calcium is again made available forfuture operations, thus obviating the serious loss incurred by washing the stone in the way hitherto adopted. Mr. F. was led to his last experiments from the MANUFACTURE OF SOLUBLE GLASS. 51 mauj faults which lie discovered in manipulating ; he supposed, at first, that by mixing sand and frag- ments of stone with the fluid silicate into a kind of paste and exposing them to the air, they would be permanently solid. But he found that stones they made very soon became disintegrated in any moist atmosphere, and particularly in England, and could never indurate. To remove this serious objection, he subjected them to the action of heat in a kiln, and he found then that at a brio-ht red the cementino; mate- rial or silicate parted with some of its free alkali, the portion thus renewed combining with some of the sand to produce an insoluble glass, unaffected by exposure to any of the acids present in the air, and not cracking by exposure to frost when damp. This artificial stone could be made so porous as to be well adapted for filtering slabs, or it could be so compacted by mechanical pressure before burning as to yield a material not inferior in its power to resist atmospheric action and even absorption. Paving slabs, garden vases, balusters, tombstones and various architectural fixtures, often constructed of terra cotta, were produced of superior quality and greater dura- bility. The stone thus made, however, after some exposure, was found to become unsightly, owing to the efflorescence of the saline matter. This patent siliceous stone was also found too ex- pensive to come into general use on a large scale, but the inventor has, at last, succeeded in reaching to a satisfactory result. The author has, many years ago in the course of his experiments, succeeded in preparing an artificial stone in the following manner : — Eluorspar, finely 52 MANUFACTURE OF SOLUBLE GLASS. ground, is mixed with the powdered soluble glass, 2 parts of the first to 1 part of the latter, the mixture made into a thin paste by the concentrated liquid soluble glass, and then as much finely powdered shell limestone, or magnesian limestone added, until the mass becomes thick enough to form into moulds or blocks, whichever may be desired ; after an expo- sure of three to four days to the atmosphere, are treated by a weak solution of chloride of calcium, (2 pounds dry chloride to the gallon of hot water,) this liquid will soon be absorbed by the stone ; it is then exposed again to the atmosphere for a week ; a dilute hydro-fiuoric acid is then applied with a sponge, and again exposed to the atmosphere ; after a lapse of a week the stone is as hard as a natural stone, and not liable to crack or to disintegrate. This composition is much easier prepared, and in- stead of common lime, chalk may be substituted, and the result is still more favorable. Instead of the en- tire quantity of lime, coarse sand may be partially added, and after the stones are moulded, are exposed to hydraulic pressure, and then exposed to the air, previous to which the chloride of calcium has to be thrown over it. The price of hydro-fluoric acid, as is used for this purpose, costs about 25 cents per pound, and this suffices for ten square feet. Furthermore it may be remarked, that exposing the stone so prepared may be subjected to a high temper- ature or not; it may be left to the operator to de- cide whether it will improve the stone by this manipu- lation. For the sandstone imitation, when 1 part liquid soluble glass is to be mixed with 2 parts powdered MANUFACTURE OF SOLUBLE GLASS. 53 soluble glass, and 15 parts of sand is added, it is ne- cessary to expose the mass to great pressure, but re- quires not the addition of chloride of calcium, while exposure to great heat is indispensable. An artificial stone may be also obtained by the use of the alkaline silicates with common chalk, which, by mixing even cold with the liquid silica, is at oncecon- Yerted into silicate of lime and carbonate of soda or potash ; this composition, when exposed to the air, be- comes in a few days hard enough so as to resemble a hydraulic lime, to adhere, when wetted again, like a cement, which may be used for restoring ci’acks and crevices in marble works and monuments. The silicification of chalk has led to numerous ex- periments, and resulted in the production of artificial stone, in the formation of hydraulic lime, hydraulic mortar and the various cements. The first successful result of the treatment of chalk with the silicate solu- tion has shown that the hardening of the chalk ex- tended to the depth of four inches, which not alone was produced from the decomposition of the silicate by the carbonate of lime, (chalk,) but also by the car- bonic acid of the atmosphere. If two balls of chalk of equal size and quality are silicified at the same time, and one of them is exposed to the atmosphere, the other kept under a bell glass, where the carbonic acid of the atmosphere is withdrawn, the first will ac- quire more hardness than the other, which proves that the silicification has assumed a hydrate of silico — car- bonate of lime — which loses by degrees its water of crystalization, and forming a precipitate of silica, contributing mainly to the hardening of the stone. A hydraulio lime may be obtained by the mixture 54 MANUFACTURE OF SOLUBLE GLASS. of a fat or rich limestone combined witli soluble glass in a dry state, say 10 parts silicate to 100 parts of air lime, both fine powder, which proves plainly the theory of the part which the silicates play in the pro- duction of the native limestone, the artificial hydrau- lic lime, mortar, cements, and the application of all silicates for the purposes of building, production of artificial stones, and the conversion of organic into in- organic materials, as we shall show hereafter. Wagner’s report on soluble glass is in the follow- ing lines : Soluble glass, called also water glass, liquid quartz, liquid silex, silicate of soda or potash, w’as accidentally discovered by the late Professor Fuchs, of Munich, in the year 181S, in the course of some investigations he was making for the preparation of pure silica. He became more familiar with its properties in 1820, and learned how to prepare it by the solution of silica in caustic potash. Afterward he studied the subject thoroughly, and became acquainted with all its pro- perties and uses. In the year 1823, as the theatre in Munich, which had been destroyed by fire, entailing great loss of life and property, was rebuilding, the Government requested a scientific commission to search for an accent that would render the wood-work and stage materials incombustible. Professor Fuchs, in association with Doctor Pettenkofer, at once in- stituted numerous experiments upon soluble glass as the best agent for this purpose, and the conclusions at which they arrived have been fully confirmed by the subsequent studies and experience of other men. In MANUFACTURE OF SOLUBLE GLASS. 55 182G soluble glass was raauufactured in Augsburg on a large scale, and sold at the rate of 25 florins the llO pounds. From this time forward a knowledge of the new compound became disseminated, and new uses were constantlj^ suggested for it. According to Professor Fuchs, there are four kinds of soluble glass : 1. Potash glass. 2. Soda glass. 3. Potash and soda glass (combined.) 4. Glazing glass. Potash Soluble glass is prepared bj fusing together : 45 pounds of quartz, 30 pounds of potash, 3 pounds of charcoal in powder, and digesting the fused and pulverized mass in water. Soda soluble is coiiiposed of: 45 pounds quartz, 23 pounds calcined soda, 3 pounds charcoal ; Or, according to Buchner, more economically of : 100 pounds quartz. Go pounds calcined glauber salt, 15 to 20 pounds coal. There are several ways of making the third variety of combined soda and potash soluble glass. J^y fusing seignette salt (tartrate of potash and soda) with quartz; by employing equal ecjuivalents of nitre or Chili salt- petre and quartz; fusing cream of tartar. Chili nitre and quartz ; or by melting at once : 56 MANUFACTUKE OF SOLUBLE GLASS. 100 pounds quartz, 28 pounds purified potash, 22 pounds calcined soda, 6 pounds charcoal powder. For technical application it is possible to mix three volumes of a concentrated potash glass solution and two volumes of a soda glass solution. The fourth variety, called glazing or fixing glass, is made by mixing perfectly saturated potash glass with soda glass, and is used for producing fast colors in stereochromy or fresco painting. There is also a wet way for the manufacture of solu- ble glass, which consists in dissolving fiint stones in concentrated soda lye in iron boilers under 7 or 8 at- mospheres of pressure, and for this purpose infusorial silica or tripoli is also specially adapted. The tripoli is first calcined to destroy all organic matter, and then introduced into boiling soda lye of 1.5 specific gravity, or potash lye of 1.135, and afterward clarified by a little water lime and evaporated to the required con- sistency. As soluble glass readily absorbs carbonic acid, it must be kept in closely stopped packages. The strength of the solution is estimated in degrees founded upon the package of dry powder dissolved in the water ; 33° means 33 parts dry glass and 67 parts water; 40° = 60 parts water and 40 parts soluble glass. In applying the solution to wood-work, roofs, fabrics, porous stones, &c., it is necessary to begin with a weak solution and to wait until it is thoroughly dry before putting on a second coat. The second application can be considerably more concentrated than the first. It will not adhere to freshly painted MANUTACTCTEE OF SOLUBLE GLASS. 5T surfaces, but when the oil is thoroughly dry and changed in tlie sun light, the water glass can be used with impunity. Care must be observed to wash out the brush thoroughly after use to prevent its harden- ing to stone. Soluble glass protects wood from the influence of fire, water and the atmosphere. The surface of wood is covered with glass, and not only will not take fire, but is less liable to decay. Some varie- ties of wood are apt to be discolored by the solution ; oak and beech are the least affected. As the soluble glass when applied to wood serves a purpose analo- gous to a varnished surface, it is necessary to avoid a too concentrated liquid, as otherwise it is liable to scale off. One pound of 33° solution, diluted with five pounds of water, is found to cover wood very well. Wood, paper, linen and straw, wdien covered with several coats of soluble glass, are no longer inflamma- ble, but simply char when exposed to fire. A coating of glass also prevents the decay and rotting of wood, and keeps out worms. Beer barrels, butter firkins and milk tubs can be easily kept clean when painted with soluble glass, and the same is true of vessels de- signed to hold sugars, syrups, wines, petroleum, &c. The most important use of soluble glass is its applica- tion to surfaces of stone and mortar. For this purpose it is necessary to impregnate the surface witli a solu- tion composed of one part 33° and three parts rain water. For this purpose a powerful pump or syringe, with a spout like a watering-pot, is used for injecting the liquid, in the form of syrup, into the pores of the stone or mortar. The surfaces thus prepared are in condition to receive the further coating of liquid quartz. 58 MANUFACTURE OF SOLUBLE GLASS. Mortar and porous limestones react upon the soluble glass, producing carbonate of lime, hydrate of lime, and, ultimately, silicate of lime, which thus presents an impervious, vitreous surface, capable of resisting the action of moisture and the atmosphere, and is in a proper state for fresco painting in mineral colors. Organic colors are apt to be destroj^ed by the alkali of the soluble glass, and hence, for fresco painting, mineral paints are alone available. A second coating of paint, rubbed up with soluble glass, is usually suffi- cient for all practical purposes, and a wall thus treated can be washed with soap and water, and kept tho- roughly clean. A plain, white color is obtained by mixing chalk with soluble glass. Zinc white, and sili- cate of soda set so rapidly, that it is necessary to add J to -J- its weight of precipitated sulphate of baryta be- fore applying the color. Baryta white and soluble glass also afford a good, fast color. Fluor spar, with pulverized glass and soluble glass, also gives an ex- ceedingly solid mass. The pigments that have been found by experience to serve the best purpose are chromate ot zinc, sulphate of cadmium, blue and green ultramarine, Schweinfurth green, oxide of chromium, cinnabar, &c. Prussian blue and colors prepared from it, and chromate of lead, will not answer, as they are destroyed by the alkali, the same as organic colors. It is well known that the fresco paifiting in the capi- tal at Washington, in the new museums in Berlin and Munich, are done with water glass, and that the suc- cess in their use is complete. Soluble glass, with or without colors, adheres closely to such metals as iron, zinc and brass, and protects them from the influences of the air and water. It has MANUFACTURE OF SOLUBLE GLASS. 59 been found that when stoves are painted with a mix- ture of solubie glass and black oxide of manganese, a species of flux is produced by the heat which does not scale off, but thoroughly protects the iron from any corroding action. Plate glass, when coated with the soluble silicate, becomes opaque, and when baryta is mixed with the liquid quartz, it assumes a fine, white appearance. If the glass be heated it becomes en- ameled, like porcelain ; and fixed colors, such as ultra- marine and oxide of chromium, open up an extensive application for soluble glass for transparencies, church windows, &c. The manufacture of artificial building stone by means of soluble glass has been conducted in Germany and England on an extensive scale. In Yi- enna barracks of an enormous size have been con- structed of such artificial stone; and the tower of the Cathedral in that city was put into thorough repair in the only way that was possible, considering the great height of the tower and the extent to which it had fallen to decay. When ground chalk or marble is stirred into a paste with soluble glass, the mass becomes so hard that it can be employed for building purposes, or for the restoration of decayed stone structures. Marble and dolomite immersed in a solution of soluble glass, and the operation repeated a number of times, take up an appreciable quantity of silica, and become so liard that they are capable of taking a fine polish. Attempts to employ such stones for lithography have been made, but not altogether with success. Artificial stone can be prepared as follows : AYell washed and gently heated sand is stirred into a warm solution of soluble glass until a proper con- 60 MANUFACTURE OF SOLUBLE GLASS. sistoDce has been reached for pouring it into a mould. After it has set it is removed from the frame, which ought to have been previously oiled, and is left to dry in an airy place. To avoid too great a consumption of water glass, a stone or brick can be put in the centre of the mould. It is also possible to stir in pebbles and' to use earthy colors in imitation of marble and con- glomerate. Such artificial material becomes very hard, and is adapted to pavements, hearths and build- ing purposes. Soluble glass can be used in the manufacture of paper hangings, for printing on paper and woven fabrics, for attaching gold and silver powder to any kind of object. Hydraulic lime can be prepared by mixing in fine powder 10 to 12 parts by weight of dry soluble glass and 100 parts of lime — this affords a ready way of preparing a hydraulic cement from ordinary lime, which is always available. One of the earliest and best known uses of soluble glass is as a cement for glass, porcelain and metals. It is put up in small packages for this purpose, and sold on the corners of streets under various names. Pieces of glass or porcelain cemented in this way will break more readily in places which were whole, than where they were repaired. The solution ought to be quite concentrated when employed for this purpose. The fragments to be repaired must be heated to the boiling point of water, and both surfaces be then moistened with the cement and pressed closely to- gether, and held in position by a strong cord, and left to dry in a warm place. By mixing sulphate of mag- nesia or calcined magnesia and soluble glass, a cement MANUFACTURE OF SOLUBLE GLASS. 61 can be formed that can be cast into moulds, and very generally be substituted for meerschaum. Soluble glass has been used in restoring several European churches, also the Houses of Parliament in London. Wood and timber and other porous substances, after being boiled for several hours in soluble glass, then exposed in tanks containing lime water or chloride of calcium, and left to dry, become highly vitrified and incombustible. Pail-road ties, ships’ timber, house and bridge beams, have been treated in this manner with entire success. The silicate is also used for penetrating fire brick and clay, and for cementing the walls of furnaces. When stirred up with chloride of calcium and used for luting down the covers of crucibles, it answers an excellent purpose. 4 HYDRAULIC LIMESTONE, CEMENTS AND PLASTERS. It is necessary to explain the main material used in building, which is lime, before we can proceed further with our subject of silicification, or imitation of the same substances by means of art, latterly ac- quired, and which bids fair to excel nature. From one of Ansted’s lectures on practical geology, the lollowing article on cements and plasters gives a good idea of their importance : “ The earliest architectural constructions to fasten together the bricks or stones of which buildings are made were of various kinds ; the most common is called mortar. It is obtained by first calcining crude limestone in a kiln, and converting it into quicklime, by depriving it of its carbonic acid. After calcining, the resulting quicklime is of a whitish or grayish pow- dery and cracked substance, which, on the application of water, absorbs a certain quantity with the evolu- tion of much heat, and crumbles into a fine powder. This powder, further moistened, made into a thin paste with water, and mixed with two or three times its own weight of sharp sand, is called mortar. Slaked lime, or hydrate of lime, as moistened quicklime is called, absorbs carbonic acid from the air, and in time mortar is reconverted into limestone ; but the opera- tion goes on under peculiar conditions, and the result HYDRAULIC LIMESTONE, CEMENTS, ETC. 63 is also peculiar ; for a film of silicate of lime is formed round each grain of sand, and thus the whole mass and the stones, between which it is placed, become in time more compact than tlie particles of limestone. As, however, there are different kinds of lime- stone, more or less impure, the result will be limes of very different qualities and properties. These re- quire special treatment to obtain from tliem the best results. The purest carbonate of lime, such as mar- ble, or chalk, make what is called a rich lime, setting firmly only in dry air, while the very impure car- bonates, in which clay is largely mixed w’ith the lime- stone, result in the production of hydraulic limes, which set more or less rapidly in moist air or even under water. Some of the impure limestones are used in the manufacture of cements by the admixture of definite proportions of foreign ingredients. Some- times, by the admixture of certain substances (as puz- zuolana) with the rich limes, instead of sand, hydraulic limes are produced. There are few subjects con- nected with the application of geology that are more important, than the determination of the material that should be used and the treatment adopted in various countries in the manufacture of cements, mortars and stuccoes. “ Commencing with nearly pure carbonates of lime, it is not difficult to trace the changes that take place in their conversion into cements f a layer of such mortar, not too thick, placed between bricks or stone, which are themselves absorbent, and kept in dry air, dries gradually and holds together such substances with extraordinary tenacity. But this is a work of years, and sometimes even centuries must run out G4 HYDEAULIO LIMESTONE, before the extreme of hardness is attained ! It is not nnnsual to find imperfectly hardened mortars in very old constructions. The mortar that fastened together the bricks in the old Roman walls is now almost everywhere so far hardened that a fracture takes place in the brick rather than in the cement. ‘‘ Limestone is widely distributed, and almost every variety, however impure, can be burnt into lime. In the manufacture of good common mortar to set in the air, pure limestones and those of fair ordinary quality are available ; but in using them, attention must be given to their composition and even texture ; thus, the hardest limestones and marbles make the fattest lime, but each variety yields a lime of dififerent quality, distinct in color, in weight, in the greediness with which it absorbs water, and in its ultimate hard- ness. The method of calcination also varies, but the general result is that, after burning the limestone, the resulting quicklime is lighter than the original stone, and differs from it essentially. To determine the na- ture of lime and its peculiar properties, perfectlj^ fresh samples should be placed in a small open basket and immersed in pure water for five or six seconds ; re- moved from the water, the loose, unabsorbed water must be allowed to run oflF, and the contents of the basket emptied into a stone or iron mortar. Accord- ing to the nature of the limestone, the lime will now exhibit some one the following phenomena : “1. It will hiss, crackle, swell, give off much va- por, and fall into powder instantly. “2. It will remain inert for some short time, not CEMENTS, ETC. G5 exceeding five or six minutes, after which the results stated in (1) will be energetically declared. “ 3. It will remain inert for more than five minutes, sometimes extending to a quarter of an hour; it then gives off vapors to a moderate extent, and cracks without noise and without much evolution of heat. “ 4. The lime will crack without noise and with little steam, but not until an hour has elapsed. 5. The lime will become scarcely warm to the touch, will not fall to powder, and will crack to a very small extent. ‘‘ In each case, before the effervescence (if any takes place) has quite disappeared, the slaking should be completed by the addition of water, not thrown upon the lime, but by the side of it, and the result should be frequently stirred, more water be added, till the whole is brought to the consistence of thick paste. When the mass has cooled, which will not take place for two or three hours, the whole should be beaten up again, until a firm but tenaceous paste is produced, resembling clay prepared for pottery manufacture. Vessels being then filled with tliis paste, or obtained from each variety of limestone, the day and hour of immersion should be marked upon them, after which they are left to solidify. “ We thus obtain a test of the nature of the materi- als used, which may belong to one of five classes : (1.) Rich limes. (2.) Poor limes. (3.) Moderately hydraulic limes. (4.) Hydraulic limes. (5.) Eminently hydraulic limes. 66 HYDKAULIC LIMESTONE, “ The word hydraulic, as applied to lime, means only, that it possesses the property of setting, or be- coming solid, in moist air or under water. “ Rich limes are obtained from the purest and hardest limestones. When slaked, they increase to double their volume; if employed alone, they remain unaltered even for years, and they are soluble in pure water. Limestones which contain from 1 to 6 per cent, of foreign substances, such as silica, alumina, magne- sia, &c., yield rich limes; but such as contain from 15 to 30 per cent., are poor limes; they increase in bulk, but little on slaking, do not set under water, and are soluble, like the rich limes, except that they leave a residuum. The fossiliferous limestones make bad mortar, as the slaking is irregular ; limestones containing much silica swell in setting, and may dislocate the masonry executed with them. Where alumina is in excess, the lime is apt to shrink and crack. Where carbonate of magnesia is combined with carbonate of lime, as in the magnesian lime- stones, the original bulk is retained. For ordinary purposes, moderately puie limestones, with a mixture of foreign substances, is a moderately pure limestone. Hydraulic limes are of great value in construction, and are extremely interesting, and are either obtained naturally from the burning of certain varieties of cal- careous rock, or are manufactured artiticially by mix- ing limestones with the requisite foreign ingredients; such are the Roman cement, Portland cement, Park- er’s and Rosendale cements. The Portland cement is largely manufactured at. the mouth of the Thames from a mixed river mud, while Roman cement is 67 CEMENTS, ETC. formed from the nodules found in the cliffs near Har- wich, all owing their quality to argillaceous admix- ture. Limestone, containing from 15 to 25 per cent, of a silicate of alumina, will burn into a good hy- draulic lime. It is also quite certain that the oxide of iron and carbonate of magnesia exercise a great influ- ence in rendering limes more hydraulic. All materi- als intended for the manufacture of cements require to be burnt carefully, and ground down to a fine pow- der, and the best cement is the lightest. When these cements are intended for the production of an artificial stone, from ten to twelve times the weight of broken stones and pebbles are added, and form also an excellent concrete. A stone made from these ce- ments just described, will bear a strain varying from 20-60 pounds to the square inch. “ The plaster cement is obtained from the gypsum, or sulphate of lime, abundant in England, France and the United States; is treated like common limestone for a cement. The calcining of gypsum does not in- volve its decomposition, but the water of solidification being driven off by the calcination, leaves only a soft white powder called plaster of Paris ; when this is again united with water, the latter is absorbed, and the mass becomes first, plastic, and then solid ; but it cannot be brought back to its original condition as a crystaline mineral, but it is converted into various substances used as cement, such as Keene'' s cement, if alum is added to the fine powdered plaster ; parian cement, if borax is used ; Martin’s cement, if pearl ashes are employed. Stucco is a very useful material for ornaments for in and out-door work, is nothin£r 68 HTDKAULIC LIMESTONE, else but a plaster of Paris, finely ground, and a weak glue added before mixing it with water. ‘‘One of the richest kinds of hydraulic lime may be obtained from volcanic minerals mixed with limes ; such material is the Puzzuolana, found near JNaples, as well as other substances found in large quantities in the neighborhood of extinct volcanic districts, as in France and on the Khine ; and which, according to its chemical analysis, consists of M per cent, of silica, 15 per cent, alumina, 87 per cent, lime, 4 per cent, magnesia, and 12 per cent, oxide of iron ; combined with lime instead of sand, have the property of render- ing even the richest limes hydraulic, and fit for use for every description of works executed in the sea or in fresh water ; they have been used from time imme- morial with great success, and may be mixed either with fat or hydraulic limes and silicate of soda to form a plastic mass, and assist in the setting of the lime. “In regard to hydraulic cements, Fremy says that the setting of cements is due to two different chemical actions : 1. To the hydration of the alurninates of lime, and 2. To puzzuolanic action, in which the hydrates of lime combine with the silicates of lime and alumina. He found that alumina is even a better flux for lime than silica, and he suggests that the very basic com- pounds of these two substances, those, for instance, containing from 80 to 90 per cent, of lime, may be -useful in the iron furnace for absorbing sulphur and phosphorus, and free the metal from those noxious im- purities; and he finds that no substance is capable of acting as a puzzuolana except the simple or double silicates of lime, containing only from 30-40 per cent, silicate, and sufficiently basic to form a gelatinous pre- 69 CEMENTS, ETC. cipitate with acid ; and he confirms Yicat’s theory, that the cause of the setting of hydraulic cements was owins: to the formation of a double silicate of alumina o and lime absorbing waters, forming hydrates and caus- ing the settino* of the materials. * o o “ Theory of Hydraulicity. “ Fremy has lately published his researches on hy- draulic cements, and in giving the theory of their hy- draulicity, he rejects the commonly received opinion that the setting of hydraulic cement is due to the hy- dration of the silicate of lime or that of double silicate of alumina and lime. These salts form no combina- tion whatever. He attributes the setting of hydraulic lime to two chemical actions : 1 st. To the hydration of the aluminate of lime ; 2 d. To the reaction of hy- drate of lime upon the silicate of lime, and the silicate of alumina and lime which exist in all cements, and in this case act as puzzuolanas. “ The calcination of the argillaceous limestone pro- duces good hydraulic cement only when the propor- tions of clay and lime are such that they form, in the first place, an aluminate of lime, represented by one of the following formulse : A1 O 3 , Ca O — Als, O3, 2 Ca O ; — AI 2 , O3, 3 Ca O ; in the second place a very sim- ple or multiple silicate of lime, which gelatinizes with acids, and approximates to the following formnlge: — Si O3, 2 Ca O — Si O3, 3 Ca 0 ; and thirdly, free lime, wliich may act upon the preceding puzzuolanic sili- cates. “ In many cases the chemical composition of an argillaceous limestone is not only the condition which 4^- TO HYDEAULIC LIMESTONE, determines the quality of the cement ; the reaction of the lime upon the clay must take place at the highest temperature. Indeed, this excessive heat produces the hydraulic elements of the cement in the basic conditions which the setting in the water requires, and which, by melting the aluminate of lime, gives it all its activity. “ Hydraulicity of Magnesia Hydrates. “ Since the publication of Fremy’s paper, Deville has read a note before the Academy of Sciences, ‘ On the Hydraulicity of Magnesia,’ in which he alludes to a specimen of magnesia prepared by the calcination of the chloride sent to him, seven years before, by M. Donny. A portion of it was left under the tap of his laboratory, constantly exposed to running water. In time it took a remarkable consistence, became hard enough to scratch marble, and was clear as alabaster. After six years exposure to the air, it has not per- ceptibly changed, and its analysis gave the following results: Water, 27.7 per cent.; carbonic acid, 8.3; alumina and oxide of iron, 1.3; magnesia, 57.1 ; sand, 5.6. Total, 100. “ Thus the substance appeared to be essentially a crystalized hydrate of magnesia, like brucite, which does not absorb carbonic acid. To prove that it was really so, M. Deville prepared magnesia by calcinihg the nitrate, powdered it, made it into a plastic mass, and sealed in a tube with some boiled distilled water. After some weeks the mass became as hard and com- pact as the other, and also crystaline and translucid. After drying in the air, this mass was found to con- 71 CEMENTS, ETC. sist of 30.7 per cent, water, and 69.3 per cent, mag- nesia, showing it to be a simple hydrate of magnesia. With similar hydrate, cast of medals were taken, which, on being placed in water, assumed the appear- ance of marble. M. Balard’s magnesia, prepared by calcining the chloride, obtained by treatment of sea water, when brought to a red heat shows astonishing hydraulic qualities, which are partially destroyed by calcining at a white heat. A mixture of chalk or marble and magnesia, in equal parts, forms a plastic mass, which, placed under water for some time, becomes hydrated and extremely hard. An average sample of Portland cement will yield, upon analysis, in one hundred p'arts : Lime, fifty-five ; iron, seven ; alumina, eight ; silica, twenty-four ; pot- ash and soda, three ; sand, two ; water, one. The essential constituents are the lime, alumina and silica.” The author delivered a discourse on cements before the Polytechnic Association, 20th April, 1866, of which the following is the substance : Cements. “ The subject for the evening — cements — was here taken up, when Dr. Lewis Feuchtwanger exhibited a number of minerals used in difterent kinds of cements, and read the following paper : “ ‘ The meaning of cement is, a paste used for unit- ing solid surfaces without always forming a combina- tion with the constituents of either surface. Many cements contain pulverulent substances which are mingled with a glutinous or very adhesive material, 72 HYDRAULIC LIMESTONE, and do not combine chemically ; others again form chemical combinations. Furthermore, many substan- ces are capable of assuming a liquid or semi-fluid form, and are thus applied between the surfaces of bodies which are firmly united when the fluid has solidified. “ ‘ The most common cements are mortar and hy- draulic cement. We have also lutes and fire cements ; but as it is important to ascertain the best mode of obtaining a good hydraulic cement, that is, a cement which hardens under water, I will at once take up this brancli of the subject, premising, however, that com- mon mortar is simply a mixture of lime, water and sand, the best proportions being one cubic foot of fresh burnt lime, weighing about thirty-five pounds, and three and one-half cubic feet of good river sand, not round, but angular ; these, with one and one-half cubic feet of water, produce about three and one-half cubic feet of good mortar. ‘ Hydraulic or Homan cement is composed of cer- tain proportions of lime, sand, clay and water ; after it has been applied a few days, and placed underwater, it becomes very hard and like stone. We now find walls and piers which are known to have been built more than a hundred years ago, and have been exposed under water, to have remained as solid as iron. The name Homan cement is derived from the district of Puzzuoli, near JSTaples, where the natural material, the tufas and puzzuolanas, are in great abundance. The Pontine marshes around Home and the volcanic tufas near Naples have always afibrded a natural cement, for they are composed of silica, alumina and lime. Besides these tufas, many marls, belonging to tlie sedimentary rocks, are used as hydraulic cement. CEMENTS, ETC. 73 The cement stones, allied to the oolitic formation, and found in argillaceous strata alternating with limestone beds, and of very curious nodular and lenticular forms and concretions, on the English and French coasts, and in this country the septaria, toadstones, Indus hel- montii of various sizes, and consisting of siliceous clay and lime strata interwoven, yield the proper material for hydraulic cement. All these marls contain, ac- cording to analysis, about seventy per cent, of car- bonate of lime, twenty per cent, of silica, and twenty per cent, of clay ; and the lime when calcined becomes caustic, and, in combination with silica, forms, under water, a chemical compound, as a hydrated silicate of lime ; and, by the presence of clay, which is a silicate of alumina, forms double silicates of greater solidity. Ca O— CO2— Si 0 ,—A], O3. ‘ The Eoman or hydraulic cement mostly con- tains, also, magnesia and iron ; whether of any essen- tial benefit or not, has not been fairly tested. It is certain that neither of these substances exercise a pernicious influence, for the reason that dolomite, a magnesian limestone found in great abundance in this country, offers a fine material when calcined with any marls, so abundant along our coast. It produces an excellent hydraulic cement. “ ‘ Tlie analysis of the hydraulic lime from E-ondout, on the JSTorth Eiver, gites in one hundred parts : Carbonic acid, 35 Magnesia, 12 Alumina, 10 Lime, 26 Silica, 15 Iron, 2 “ ‘ Sand or quartz, which by itself is unfit for a mortar, when calcined with lime, becomes very suit- 74 HYDRAULIC LIMESTONE, able for a hydraulic cement or artificial stone, for it forms a silicate of lime. More than thirty years ago, 1 entertained the idea of preserving timber by the infiltration of silicate of lime into the cells of planks, timber, and through the double chemical affinity of silicate of soda and sulphate of lime. The experi- ments I made then, in the Brooklyn Navy Yard, with pier piles and wooden vats, were very satisfactory. “ ‘ For water-proofing cellars and buildings, not alone the best hydraulic, but other cements have of late years been introduced in this city ; for instance, the asphalt cement, which is very extensively em- ployed in the foundation of buildings. Having made, myself, many experiments, for a number ofyears past, in order to introduce the silica cement, or the soluble glass in combination with alkaline earths as a base, and met with varied success, I beg to ofier here a sample of a cement which consists of silicate of lime combined with manganese and fiuorspar, or fiuoride of calcium, which becomes very hard, and which, I think, will, after some improvement in the prepara- tion, be found highly useful in keeping dry walls and cellars. I have mixed equal quantities of manganese, limestone, fluorspar and dry soluble glass, and make the whole mass plastic by the liquid soluble glass, and apply it while soft ; after the lapse of a few hours it becomes very hard. ’ u 4 Yire cements are lutes, for crevices and joints, which are intended to be used for furnaces, iron pipes and retorts exposed to constant red and white heat; or for joining gas and water pipes, and many other substances, may, if judiciously applied, prove very ac- ceptable. I beg to offer a few which I consider useful : CEMENTS, ETC. 75 ‘‘‘No. 1. Iron Cement or Lute. — Erick dust and fire clay in equal parts, borax, red lead and sal am- moniac, one-tenth of the other ingredients ; cast iron turnings. The whole mixture made up with water so as to knead them together, and spread it in layers. It is suitable for crevices or joints of iron pipes, fur- nace doors, man holes of boilers, etc. “ ‘ No. 2. A Steam-resisting Cement. — Twm parts litharge, one part sand, one part slaked lime ; made plastic with hot glue. “ ‘ No. 3. An Iron Cement — Manganese twenty- four parts, red lead five parts ; formed into a paste w'ith linseed oil. “ ‘No. 4. Cement for Fastening Iron and Stone.— Calcined plaster, iron filings and hot glue. The three following are good cements for cisterns, etc.: “ ‘ 1st. Ten parts of plaster of Paris, two of Glauber salts, four of clay, and four of lime. “ ‘ 2d. Twenty-two parts of clay, nine of iron filings, sixtj^-three of lime, one of magnesia, one of pearl ash and ten of charcoal. “ ‘ 3d. Thirt}^ parts of sand, seventy of lime, three of litharge, made up with linseed oil. “‘A very remarkable cement for almost any sub- stance is made in the following manner: Either glue or gelatine is swelled up in water and then immersed in linseed oil and heated. It dissolves and forms a paste of great tenacity, which, when dry, resists dampness perfectly. Two pieces of wood joined by it may separate anywhere except at the joint. 76 HYDKAULIO LIMESTONE, “ ‘The china or diamond cement, for joining glass or china ware, consists of gum mastic and ammonia dissolved in alcohol, to which is added hot glue. Spalding’s glue is the old Berzelius paste, that is, glue dissolved in acetic acid. The Japanese cement is rice flour made into a paste and dried. “ ‘ In 1 811, a patent for a lime cement was obtained bj Kulilmann, who adds an alkali, like soda or pot- ash, before calcining the limestone with sand and clay, so as to produce a soluble silicate with the ingredients of hydraulic cement. “ ' The Portland stone or cement, so extensively used in England, and exported largely from there to all parts of the globe, and forming the base of many patent cements, such as Beese’s and others, is nothing but powdered oolite, a mineral lime deposit. Harne- lin’s mastic cement, another very celebrated cement, is prepared from sixty-two parts of oolite, thirty-five of sand, and three of litharge. “ ‘ The celebrated French cement of Bouilly is said to be prepared from the Boulogne pebbles, called go- lets, which are marly nodules of all sizes, like the sep- tarias and marly concretions of other countries. A number of years ago I prepared a good hj^draulic ce- ment from one part of the poorest limestone, one of clay and three of sand. I also prepared a terra cotta, which is likewise a cement, composed of clay and sand, slowly dried and calcined. “‘Among the great variety of cements .in which silica is the active principal, the two following are very useful ; “ ‘ 1. A mortar, to be made as hard as any cement. 77 CEMENTS, ETC. and which does not crack in setting, and even of great usefulness as hydraulic cement under water, is obtained by mixing finely slaked lime with fine sand (the angular grains are always preferable to the round grains for producing a good mortar.) By mix- ing the sand thus prepared with finely powdered quicklime, and stir the mixture thoroughly. During the process the mass heats, and may then be em- ployed as mortar, to which has to be added to one- eighth of the mass the liquid silicate of soda. “ ‘ One part of good slaked lime was used with three parts of sand, and to this was added three-fourths of its weight of finely powdered quicklime ; the mortar containing one-eighth of the liquid silicate of soda was then used as a foundation wall, and in four days had become so hard that a piece of sharp iron would not attack it ; and in two months afterwards it had be- come as hard as the stones of the wall. “ ‘ 2. A thin coating of slaked lime made into paste with water or whitewash is put at once on the stone, and before becoming quite dry apply the silicate so- lution over the paste, by which the mass becomes completely insoluble ; a petrification takes place if ap- plied to vegetable substances, decomposition is pre- vented, porous building stone and brick are protected against air and damp. “ ‘ Common Moktar. “ ‘ Limestone, an impure carbonate of lime, when exposed to a red heat, loses carbonic acid gas, and the oxide of calcium or lime remains. This process of burning lime, as it is called, is accelerated by the 78 HYDEAULIO LIMESTONE, presence of moisture in the stone, or by the introduc- tion of a small quantity of steam into the lime kiln. The hydrate of lime reacts with considerable power on siliceous compounds, but the action only takes place at the surfaces, and unless the lime is used in very thin layers, between smooth stones, it still re- tains, in the centre of the layer, its own soft and fria- ble condition. “ ‘In order to make the hydrate of lime effective as a cement, it is mixed with sand, one of the most abundant of natural compounds, now regarded as con- sisting of two_atoms of oxygen and one of silicon. Equal parts of tine and coarse sand are said to be better than either quality used separately with lime. Mortar designed for exterior or surface work is gen- erally made with fine sand. When lime is compara- tively free from impurities, and crumbles to a tine powder on being slaked, it is called fat lime, and will require about six times its own weight of sand, or, if estimated by bulk, one cubic foot of semi-tiuid lime and water, called the milk of lime, will require about three or four cubic feet of sand. This mortar is very effective as a cement when well dried or set, but if it is placed in water, the lime is gradually dissolved and the mass is disintegrated. • a c Hydraulic Cement. “ ‘ For all permanent structures under water it is, therefore, essential to use a material called hydraulic cement, which is a mixture of lime with other oxides possessing the valuable quality of hardening until it has the solidity and permanency of the masses of rock CEMENTS, ETC. 79 bound together bj it. The varieties of limestone from wliich hydraulic cement is made, wlien burned, yield a lime tliat is very slowly slaked. All that is required is to add water until it attains the consistency of dough ; it will then harden and become concrete. These hydraulic limes may be made artiticially by mixing with impure slaked lime a quantity of burnt clay in the proper proportions’. The celebrated Ro- man cement is a porous volcanic rock found at Puzzuoli, near Naples, and called there puzzuolana. It consists of silicate of alumina, soda and lime. This substance is pulverized and mixed with common lime.’ ” The Silicate Hydraulic Cement in the Preven- tion OF Wall-Damp. In laying the foundation of any building, the mat- ter of particular consideration should be the thorough drainage of the site, and next to that complete pre- vention of wall-damp, that is, the rising of moisture bj’ capillary attraction or otherwise, in the heart of the brick or stone wmrk, the particulars of which have been lately described in the Manufacturer and Buildeds Journal^ to which the author had added the silicification of the bricks and plaster. It states that wherever brickwork comes in contact with the earth, or even with adjacent walls which may happen to be damp, there the infection is certain to take, and there is no easy cure for it, if once it makes an en- trance. The readiest remedy in all cases is a layer of fine concrete, which may be thinly coated on the top with 80 IIYDEAULIG LIMESTONE, asphaltum laid on hot. This done all around the top of the walls, external and internal, the piers and every piece of brickwork, that in any manner has connec- tion with the ground, then the bricks, which ought to be specially prepared before calcination with a silicate solution, should be heated over charcoal fur- naces and dipped in the asphaltum before being laid. It is evident that a preventive course could thus be formed above ground at a trifling expense, wholly impervious to wall-damp, at the same time giving a base to the superstructure of a quality very far superior to any now in use. Coating the outside face of the wall with water-proof silicated cement, as has been before noticed, is the only safeguard against capillary attraction from below, and excluding the ex- ternal air which might let the artificial heat of the rooms to attract the enemy of wall-damp. It is known that common brick will absorb one-fifth of its weight of water, and where the storm drives the rain con- tinually against the face of a wall for a sufficient time to permit the interior heat to attract it, the inside of the wall must, of necessity, be damp, and the papering become mouldy, as well as the ceiling, will next be rotten. This cause of wall-damp is one that cannot be too carefully guarded against, as it is one to which may be referred the early decay of many residences, as well as the inception of these pulmonary symptoms which so surely steal away the health and ultimately the life of many a victim. The mortar to be used in the foundation and the wall ought to be very well prepared, so as to possess all the hydraulic properties and silicification, and cau- tion should be taken in not using sea sand, which will CEMENTS, ETC. 81 certainly create the damp by absorbing all the water in the atmosphere, this being the chemical effect of its saline property. The surface of the walls of the rooms must be well attended to ; the plaster of Paris, which is generally employed, ought to be properly silicified, so as to pre- vent the absorption of the natural damp of the atmos- phere created in uninhabited and unheated rooms. It is preferable to paint rooms than to paper them, for the white lead and linseed oil, with some manganese to facilitate the drying, becomes hard after a short time, and assists tiie fresh plaster wall in preventing the admission of the moisture, as the fourth coating of Avhite lead is applied witli equal proportions of oil and spirits of turpentine, which has the property of being very volatile, will evaporate entirely, leaving the sur- face of the paint of a very compact and hard nature, and rendering the plaster incapable of absorption. Damp Walls and Cellars. The application of silicates for preventing the pene- tration of rain or moisture in houses, whereby the ■walls are absorbing the same, and render the paper- hangings or delicate paint unfit, so as to destroy their appearance, has been amply and satisfactorily proved. The silicates of soda and potash, or either of them, are mixed with pure wdiite lead or zinc,- and applied soon after upon the walls, which will dry immediately. The presence of damp in walls arises from three causes : either from the porous condition of the mate- rials of which they are built, allowing the penetration of damp from without ; from the existence of salts in 82 HYDBAtJLIC LIMESTONE, the mortar, bricks or stone, which absorb and give out moisture, according to the changes of the weather, or from damp foundations. The first only can be reme- died by the application of external coatings, the second by battening the walls, and the last by removing the adjacent earth from the foundations. As has already been stated, a single application of a paint formed with lead or zinc has proved very successful. The second application is the silicate so- lution with china clay, or pure alumina, which has the advantage of not drying so quick as that with lead or zinc. In all cases the j^aints must be put on uni- formly, so that the whole wall surface should be com- pletely covered with the solid coat; and in order to effect this, a rough stucco surface, from two to three coats, may be required. It is found also useful to apply the second coat thinner than the first. The mixture of liquid silicate of soda with clay and that of whiting, or washed carbonate of lime, may probably be the most reliable for keeping out damp from walls as well as cellars. On applying the lead or zinc as the first coat, either of them or both, it may be done in the following manner : Mix them with a little water and lay them on the stone, they will dry very soon ; apply then the silicate solution by means of a syringe. If the application is to be made on stone which shows some decay, it is necessary to remove first the same, apply then the aluminous silicate of soda, (by an equal mixture of liquid silicate with fine white clay,) and then apply the carbonate lime and silicate wash with an ordinary paint brush, stippling it so as to give it the appear- • CEMENTS, ETC. 83 ance of tlie granulated surface of tlie stone. "When dry, it will adhere sufficiently to allow of other washes of silicates beino; brushed on it. The conditions necessary for success are: 1. The wall should be coated with a porous mate- rial, such as lime or Portland cement. 2. The coating must be perfect. A M^all which has been once painted is altogether unfit for any applica- tion of siliceous washes, for the reason that it is not absorbent enough. The best ground for any siliceous work is lime and sand. In new buildings it would be better to use lime and sand at once, and then to cover it with lime and silicate of alumina and soda. The precipitated sulphate of baryta maj^ safely be applied in the sili- cate of soda for all the above purposes, and it will pro- duce a good coating and a fine paint. MANUFACTURI5 OF PORTLAND CeMENT. Portland cement w^as introduced to public notice under a patent by an Englishman nearly fifty years ago, and a partial monopoly in its production has been kej)t up, inasmuch as inexhaustible beds of the raw material from which it is made, and an abundant supply of fuel necessary for their economical manu- facture, is at hand. It is strange that under these con- ditions French engineers should have obtained the start of their professional confreres^ and that they should have been the first to demonstrate by experiments, and subsequently by the erection ot magnificent harbor works on their seaboard, the valuable properties of this 84 : HYDEAULIC LIMESTONE, excellent constructive material. We may date the ex- tensive employment of Portland cement in England from the commencement of the metropolitan main- drainage works. During the last fifteen years the manufacture of Portland cement has gone on steadily increasing, until at the present day we find that little short of 400,000 tons per annum are made in the county ofXent — the centre of cement manufacture — irrespective of the productions of many minor factories in different parts of the country. The chemistry of the setting of Portland cement is by no means so well understood as it ought to be. There is no doubt, however, that, like the hydraulic lime and natural cements, it is, chemically speaking, a double silicate of lime and alumina ; silicic acid is generated by the hydration of the cement, and forms insoluble salts with the lime and alumina bases. It is a curious fact that Portland cement hardens more rapidly when salt water is employed. According to Schweitzer, 1,000 grains of sea-water in the English Channel contains 27,060 grains of chloride of sodium ; soluble silica has a known preference for alkaline bases, and it is not improbable, when the cement is hydrated with sea- water, that the chloride of sodium is decomposed, the silicic acid of the cement com- bining with the sodium and oxygen' of the water, and forming thereby a silicate of soda, or a species of crude glass. Portland cement is of two classes, which, for the sake of distinction, may be termed ‘‘Engineers’” ce- ment and “ Plasterers’ ” cement. The former is the more costly ; it is usually described by manufacturers as “ best heavy tested it weighs from 112 pounds to 85 CEMENTS, ETC. 120 pounds to the bushel, is slow setting, and of great strength ; the latter is a light cement, quick setting, and of inferior strength when compared with the other. It must be understood that our remarks apply exclusively to “ Engineers’ ” cement. Portland cement is made from chalk and alluvial clay ; the factories on the banks of the Thames use white chalk, those on the Medwa}^ gray chalk; the latter is probably preferable, inasmuch as it contains large quantities of silicious matter. Mr. Pead, in his treatise on “ Portland Cement,” says that “ the present and safest proportions, provided both chalk and clay are selected free from sand, are four parts of chalk from the Medway, (gray,) or three parts of Thames, (white,) with one of clay by measure.” These materials are placed in mills of simple construction, each having a circular pan, 6 feet in diameter and 2 feet deep, in wdiich two “ edge runners,” I feet 6 inches in diame- ter, are kept continually going ; a constant stream of ’water flows into the pan, and as the edge runners” revolve, the chalk and clay are thoroughly ground, and, being thus converted into a fluid state, they Alter through a band of flne brass wire gauze fixed to the side of the pan, and flow through wooden “ launders” into tanks or settling reservoirs. One washmill will feed four tanks, each of which is about 100 feet long, 40 feet broad and 4 feet deep. AVhen one of these has been filled in the manner just described, the same process is applied to the others in succession. About three weeks after the tanks are filled, the whole of the materials will be precipitated, the clear water being drained oif in the meantime through a small weir in the brick side of the tank ; the residuum is a plastic 86 HTDRAULIO LIMESTONE, mixture of the consistency of “ putty,” and not much unlike it in color. The next process is to convey this precipitate from the tank to the “ drying floors,” over which it is spread in a layer about 6 inches thick ; each floor is 40 feet by 30 feet; it consists of an outer skin of boiler plates, resting on a series of brick ovens and flues. The object of this arrangement is to render the plates sufficiently hot to effect the rapid desicca- tion of the water from the superincumbent layer, a process generally accomplished in about twelve hours. The materials having thus been thoroughly dried, are ready for conveyance to the kilns. The “charge” consists of alternate layers of coke and raw materials, the burning generally occupying thirty-six hours. When the contents of the kiln becomes sufficiently cool, the “ clinkers,” or cement stones — for the mix- ture has now assumed that form- — are drawn and re- moved to a floor where the larger pieces are broken, and the whole of the burnt materials are then con- veyed to the hoppers of the grinding mills, where, passing under rapidly revolving horizontal burr-stones, they are ground into an almost impalpable powder. The cement issues from the mill at a temperature of about 160°, and the now manufactured material is wheeled away, and placed in a layer from 2 feet to 3 feet thick over the floor of a cool shed ; it is subse- quently packed in casks or sacks for conveyance from the wmrks. The essential conditions for the manufac- ture of sood Portland cement are : 1. The chalk and clay should be thoroughly mixed in the washrnills, and the fluid materials delivered by “ laundei's” over the entire area of the settling tanks. 2. The contents of the kilns ought to be burnt equally throughout. 3. CEMENTS, ETC. 87 Tlie burnt materials should be ground very fine. 4. After coming fruin the mill the cement should be spread over the fioor of a shed, and allowed to remain there for at least a fortnight previously to being packed into casks or sacks. The strength of Portland cement increases as its specific gravity increases ; phe tensile tests are usually made with briquettes, the standard size for the neck being IJin. by l|-in. ; and it must be understood that all experiments referred to have reference to the weight necessary to sever square inches of neat cement. It appears from Mr. Grant’s valuable paper, read before the Institution of Civil Engineers in December, 1865, that Portland cement gains from 20 to 30 per cent, in strength by setting under water; it is usual, therefore, to place the best briquettes in water, after gaging, and allow them to remain there until they are to be tested. The following table has been compiled from a recent series of experiments ; it shows the averas^e tensile streno-th of Portland cement as com- pared with the natural cements; the test blocks were of standard size of 2J square inches, and placed in water, as before described : O II 1 Breaking weight 1 two days old. 1 Breaking weight 1 four days old. •5 0 > GQ c3 fcJL'O .5 a § S lbs. lbs. lbs. lbs. Portland Cement, 119 598 914 1,024 Roman Cement, 76 200 240 280 Medina Cement, 69 280 313 313 Cement de Zumaya, (Spanish,) 84 306 409 88 HYDRAULIC LIMESTONE, The Builders' Trade Circular vouches for the ac- curacy of these figures. Mr. Grant’s tables show conclusively that the strength of gaged Portland cement increases with age ; from his experiments, it appears that the breaking weight of rest blocks, one week old, one year old, and two years old, are as 1, 1.5, and 1.62. The ultimate maximum tensile strength has not as }^et been ascer- tained ; experiments are, however, being conducted periodically with a view to determine this important point. Mr. Grant gives the average tensile strength of cement weighing 119 pounds to the bushel as 777 pounds, whereas we give it as 1,024: pounds ; the ex- cess of the breaking weight, as recorded by us, may probably be accounted for by improved manufacture since Mr. Grant’s experiments were made. Portland cement now forms an important item in the list of our manufactures ; but even now its valuable properties are not as fully appreciated as they deserve to be. Good Portland cement should present a fine and homogeneous powder; it should set firmly and quick- ly, when used in works exposed to the surf, filling up joints in water works, etc., otherwise too rapid setting is not desirable. It should neither contract nor ex- pand; it ought to assume a uniform, bright, gray-stone color, free from brown spots ; it should possess great cementing properties, adhere strongly to the stone, and bear a high addition of sand. Finally, it ought to be free from adulterations, while the ton should have the generally adopted weight of 2U0 kilogrammes. It is to be recommended, under all circumstances, and CEMENTS. ETC. 89 even if tlie cement has been procured fi’om well-known inanufactiirers, to weigh it on delivery, and to keep an accurate account of it. It is very often the case that the weight is considerably below 200 kilo- grammes, due either to^ie frequent use of the same barrel, which almost inevitably gets smaller, or to bad packing, which produces incompactness; or to unpacking it in smaller barrels, which is often done by second or third hand dealers. A difference of ten or twenty kilogrammes per ton, which often occurs away from the centres of trade, ought certainly to be taken into consideration, if oc- curring in larger quantities. In order to examine cements for their fineness and uniformity of mixture, it is only necessary to pass samples of different barrels through sieves of twenty meslies per centimetre. There should, properly speaking, remain nothing on the sieve, and under all circumstances, preference must be given to the cement wdiich most nearly fulfills these conditions ; for the finer and more uniformly the ce- ment is divided, the more promptly and simultaneously will the chemical reactions take place, the more perfect its combining and cementing properties, and the less fear is to be entertained about a durability of the mass after it has once properly set. The most common adulterations are inferior or spoiled cement, slags, ashes, clay and sand. They are most easily discovered by constant shaking of a sample with an abundant amount of water, after which it is allowed to settle in a high, narrow vessel. The cement to be examined is to be put in the glass filled two-thirds full of water, after which it must be shaken at once, or the cement 90 HYDRAULIC LIMESTONE, will cake together and stick to the vessel. Ashes and clay deposit on top, on account of their smaller specific gravity, and the water in this case generally looks turbid. The upper portion of the sediment generally fails then to harden at all,%ut exhibits a distinctly different color from the rest of the mass. A close ex- amination of it will then usually disclose the nature of the adulteration. An addition of ashes may be recognised by treating the upper layer with muriatic acid, upon which an abundant development of carbonic acid will take place, while a plastic residue indicates an adulteration with clay. Sand will be found divided throughout the mass, but especially in the lower portions. It is discovered in treating the cement, by moderately strong boiling muriatic acid, which dissolves the cement, but leaves the sand behind. Most dangerous, however, because not recognisable at all, is basic slag, or spoiled cement, which necessarily injures the binding quality and strength. An adul- teration of this kind is not very injurious when the cement is not much exposed to the action of water, if a slag is employed that is not too basic, and that sets with lime, as is the case with many blast-furnace slags. In such cases it is acted upon by the liberated lime, and thus it becomes a cement itself, while superbasic and very acid slags, that are not decomposable by acids, behave as inert masses, taking simply the part of sand. When made into a paste, with sufficient water to produce a mortar which slides smoothly from the CEMENTS, ETC. 91 trowel, pure cement should not set in less than twenty or thirty minutes. Yet the view that the most quickly-setting cement is the best, is found to be quite generally disseminated. We read, for instance, in a book on this subject of re- cent date: “ Excellent cements, such as the Portland cement, Homan cement, and others, if immersed in water, harden in a few minutes, while inferior cements only attain after a few hours such a degree of hard- ness that the}^ will not take an impression by the fingers.” This view is not quite correct, for it can be proven that rapidly-hardening cements will, under otherwise equal circumstances, never attain such a degree of solidity and strength as slowly-setting ones. They will, therefore, not bear the same amount of sand. Hapidly-setting cements ought, therefore, to be avoided when possible, and only used in filling up cracks in water works, or for similar purposes; firstljgbe- cause they fail to attain the same degree of solidity and power of resistance as the slowl)^-setting ones ; second- ly, because they can only be worked with difficulty in small quantities, and only givdng the best result of which the)^ are capable, when the mason is exceeding!}" prompt and skillful ; thirdly, because they accomplish much less than they really should by being worked in a careless manner, besides causing considerable delay. For, if the hardening process has once begun in the mortar-box, the most assiduous working up of the solidifying mass will not (especially if more water is added) entirely remedy the evil. By employing slowly-binding cements, these draw- backs are in a great measure avoided. Portland ce- 92 HTDEAULIC LIMESTONE, ment, which, if mixed with the necessary amount of water, say from thirty to forty per cent, in weight, and if not setting in less than twenty minutes, will scarcely increase in temperature ; quickly-hardening cement, however, will get hot in consequence of the rapid chemical action which takes place. Still, there exist also limits in regard, to slew-setting. If it sets too slowly, it remains resistless, and is pressed out of the joints, for which reason the continuation of the work will be prevented until the mass is sufficiently hardened. If once set under water, the cement should continu- ally get harder without changing its volume, cracking, or perhaps even falling to pieces. The cement should completely fill the mould in which it has been pre- pared as thick paste ; it should not suffer any contrac- tion by the evaporation of water added in surplus. On the other hand, there should be no increase of volume by swelling. The tests to be made follow from these considera- tions : Small preserve-glasses are filled with cement and the necessary quantity of water; another portion is spread over a glass plate, or a previously well-mois- tened brick, so as to form a cake of about five centi- metres in diameter, or a larger surface is covered with a layer of one centimetre. From the rest some balls are formed before it has become solid, or a new por- tion of the powder is taken, and so much water added that balls may be formed. A sewer constructed of concrete, consisting of one- seventh cement to six-sevenths of sand, and lined inside wdth cement, was regarded by Mr. Grant as the cheap- CEMENTS, ETC. 93 est form of sewer combining strength with soundness. Tables were also given of the strength of 589/271 bushels of Portland cement, used during the last five years on various works south of the river Thames, showing an average tensile strain at the end of a week of 806.63 pounds, equal to 358.5 pounds per square inch, being an improvement on that reported five years ago of 89 pounds per square inch. At the end of thirty days, 37,200 bushels of the same cement, as ascertained by 1,180 tests, had an average strength of 455 pounds per square inch. Further experience had confirmed the earlier conclusions that the strength of Portland cement increased with its specitic gravity, its more perfect pulverization, and its thorough admix- ture with the minimum quantity of water in forming mortar. Heavy cement, weighing 123 pounds per bushel, took about two years to attain its maximum strength when used pure; but by the admixture of sand or gravel, cement, mortar or concrete w^as re- duced in strength, and set less rapidly than pure ce- ment. Poman cement, though from its quick setting properly very valuable for many purposes, deteriorated after exposure to air before use about twice as much as Portland cement, if measured by strength. In making cement concrete, it would, from this, seem - desirable to spend no more time than was absolutely necessary to effect a thorough admixture of the cement with the sand and gravel. Under the name of liquid stone, is the application of the alkaline silicates in the following manner : 5 '^ 94 HYDRAULIC LIMESTONE, ‘‘ The first idea that suggests itself of the use of such a liquid, is the preparation of artificial stones for orna~ mental and building purposes. Should it be possible to produce this petrifying liquid cheap enough, build- ing stones in all their variety could be made and cemented together with the same petrifying solution. The cost of cast fiint marble statuary, tombstones, baths, tables, mantel-pieces and ornaments of all kinds, would be, of course, much less than if laboriously out from the stone, and they come quickly into universal use. In a similar way, as photography now diffuses the master-pieces of the art of painting among all classes of society, and cultivates their taste, the art of casting fiint marhle would multiply and difi'use the master-pieces of sculpture, and adorn our public build- ings, gardens and parks. Bas reliefs, cameos, cornices, columns, pillars, etc., might be produced at compara- tively cheap prices. Should the liquid be of a kind to permit its application to outside or inside walls, like plaster, then we could cover our brick and stone houses with white or colored fiint-marble fronts, and our churches, halls, theatres, parlors and rooms with glass- like walls and ceilings, colored ad libitum -with elegant frescoes as durable as the still fresh paintings at Her- culaneum and Pompeii ; while the fioors could be inlaid with beautifully colored stones in mosaic style. “ Another important application for such a liquid would be the one to render wood 7ion-infiammable, rot and waterproof. By making wood non-infiammable, we should greatly diminish the danger to which most of our old and new buildings are now exposed. This could easily be effected, and with not much cost, by impregnating the wood with a properly prepared sola- 95 CEMENTS, ETC. tion of flint ; for, if once the pores of the wood, which by their capillary action cause the communication of the tire to the whole structure, be stopped up by the incombustible and non-conducting silica, the wood becomes non-inflammable, and at the same time proof against water and decay. Not less important would be the partial silicification of rail-road sleepers and cross ties, house, ship and bridge timber ; they would be stronger and last longer. Telegraph poles would, when properly treated, become more durable, and be, in addition, better non-conductors of electricity. What a new field would such a petrifying fluid open to the manufacture of incombustible paints and var- nishes ? It might also be mixed with paper pulp, or cheap vegetable or animal fibre, and serve for the manufacture of a variety of useful articles, such as staircases, boxes, trunks, soles for boots and shoes, pat- terns, moulds, handles, parts of machinery, photo- graphic instruments, piano keys ; and, further, it might be used as a coating for preventing the oxyda- tion of iron or other metals. We must not overlook another important application in the use of the liquid flint — the one for the preservation of old monuments and stone buildings. It might, perhaps, also serve as a medium for the preservation of meat, fruit, vegeta- bles, eggs, etc. The linings of barrels, for oils and other liquids, the coating of tanks, tubs, sulphurki acid chambers, etc., are other useful applications of this liquid. “ Metallurgy could be very materially benefited by a process whereby quartz could cheaply and speedily be dissolved in water; for we could then take the gold quartz of Nova Scotia, New-TIampshire or Cana- 96 HYDKAULIO LIMESTONE, da, and dissolve the quartz and obtain all the gold as a precipitate. Of course, as the liquid flint could be used for so many useful purposes, and be sold for a good price, the extraction of the gold would be very cheap, and, so to speak, cost less than nothing, as the extraction price of the gold would be more than paid for by the amount realized from the sale or use of the liquid.” Hydraulic Mortar from American Limestone. These limestones contain mostly lime, silica, alu- mina, oxide of iron and magnesia, which form the proper materials for the preparation of mortars ; they will withstand the action of water and moisture bet- ter in proportion, as the quantity of silica, alumina and magnesia is larger ; they contain 40 per cent, carbonate of lime, 30 per cent, carbonate of magne- sia, and 20 per cent, silica, the balance is alumina and oxide of iron, and they form a good mortar and a good building material ; but when the magnesia is too prevalent, will deteriorate it for building pur- poses, it being too friable. The dolomite, which is also called bitterspar, a magnesian limestone, is a double carbonate of lime and magnesia, and abun- dant in the United States, is a granular limestone, and a hardness of 3.5, a spec. gr. of 3.1, and consist- ing of 70 per cent, lime and nearly 40 per cent, of magnesia and some oxide of iron and manganese ; is unfit by itself as a building material, having a great tendency to crumble into small fragments, and forms likewise an inferior material for burning and con- verting it into cement, because it lacks the silica in- CEMENTS, E,TC. 97 dispensable for this purpose. By an addition of an alkaline silicate, either the silicate of potash or soda, and an addition of some alumina, will, after burning, produce a good hydraulic cement, particularly in such localities where no good native hydraulic limestone is found. Not alone France and Germany are particu- larly rich in deposits of hydraulic lime, and in the United States likewise, but these in our neighborhood may be particularly mentioned at Uondout, on the western shore of the Hudson Kiver, 100 miles distant from New-York. The quarrying in those subterra- nean rocks for hydraulic cement and also common limestone is carried on in that region, along a large extent of the valley of the Kosedale Hiver ; through this valley the Hudson and Delaware Canal is con- structed, which brings the coal from the Lackawanna valley at Carbondale directly to the Hudson Hiver. This coal being a very pure anthracite, is admirably adapted for use in the limestone and cement furnaces situated at the junction of this canal with the Hudson Hiver. In burning hydraulic limestone, not only the car- bonic acid and water of hydration are drawn off, as is the case with common limestone, but after the lime and magnesia have parted with their carbonic acid, at the high temperature of the furnace, they act on the silica and alumina, as it were, like twm powerful bases, and a silicate of lime and magnesia, as also silicate of alumina and aluminate of lime, are formed. The ex- act chemical reaction during the burning process is, however, as yet not well understood, and undoubtedly varies in different limestones, according to their chemical constitution, which latter appears also to 98 HYDRAULIO LIMESTONE, vary considerably, but without affecting materially their useful properties. In regard to the theoretical causes of the liardening process, which takes place under water, it may be re- marked that this curious and interesting phenomenon, being of an entirely chemical nature, has largely drawn towards itself the attention of eminent chemists, who have attempted to explain it in accordance with well known chemical laws. All hydraulic limestones may, by the ordinary method of analysis, be decomposed into two component parts ; the one consisting of the carbonates of the earth, such as lime, magnesia, etc., which, like ordinary limestones, yield a fat lime ; the other, a silicate, or rather a mixture of the silicates of alumina, magnesia, lime, and sometimes potassa, as we find in the felspar, which is a silicate of alumina and potash, and a greater or less excess of free silica ; the latter constituent is, therefore, simply a kind of clay. The reaction during the burning process has been already alluded to. Now, when such freshl}^ burnt cement is mixed with water, the excess of caustic lime as well as the compound into which the silicious clay has been converted during the burning, react upon one another in such a manner, tliat a solid stone-like silicate is produced in the humid way, the water has a double action ; dry substances, such as lime and sili- cate of alumina, do not act one upon another, unless the solvent power of water is brought into play so as to bring them into close contact; the water transfers continually the lime it dissolves to the silica. The absolute necessity of keeping such mortar under water, in order to have it harden, is thus explained. Another action of the water is this : it enters into a state of 99 CEMENTS, ETC. hydration in the silicate of lime as soon as formed. It must also be observed, that the molecular condition of the silica is of the utmost importance in this process. Fine sand will not combine with lime, when the latter is dissolved in water that is in a form known under the name of limewater ; but silica, precipitated from a soluble glass solution by means of an acid, which pro- duces the gelatinous form of silica, will at once com- bine with the lime in limewater and form a silicate of lime. The silica in the hydraulic mortar is also in a state, not like tine sand, but chemically combined and dissolved iji the mass, and therefore ready to combine with the lime in limewater. Next in importance to silica is the magnesia, which renders the lime hydrau- lic, which, according to Fuchs, has been proved that lime and magnesia well mixed will harden under water to a certain extent without the addition of silica; for we have in Germany a hydraulic lime containing only 4 per cent. When silica is found to the extent of 52 per cent., the point of saturation is reached, and such limestone is no more hydraulic. Alumina and iron may be entirely absent, although the former is always present in'the best kinds of hydraulic mortars, of which that of Eondout, usually called Kosedale cement, and wdth the employment of which the Croton Water Works of New- York City w’ere built, is the best on this continent. It is conhdently to be hoped, that by the proper application of alkaline, silicates will contribute much to the manufacture of an artificial hydraulic cement. 100 HYDRAULIC LIMESTONE, German Hydraulic Cement. This material, artificially prepared, is in great use, and is of very peculiar composition ; unquestionably it is intended to form a silicate-aluminate of lime, or, in other words, an argillaceous silicate, but the ad- mixture, such as charcoal and iron filings, cannot be explained, but the base being obtained by the pro- duction of an alkaline silicate, bespeaks for it a usefnl vehicle as a cement. It is prepared with 25 parts common clay, 60 parts lime, 10 parts magnesian limestone, 10 parts iron filings, and 10 parts of black oxide of manganese ; these materials, in very fine powders, are made plastic by the liquid silicate of soda, at once applied as a cement or mortar, but it will not set at once, six hours being required for the mass to harden. Hardness of Ancient Mortars. Mr. Spillar communicated a paper on this subject to the British Association in 1868, of which the fol- lowing are the conclusions, from the chemical exami- nation of the ancient mortars from Burgh, Pevesney, and other Boinan castles : that the lime and carbonic acid are invariably united in monatomic proportions, as in the original limestone rock ; and that there is no evidence of the hydrate of lime having at any time exerted a power of corroding the surfaces of sand, fiint, pebbles, or even of burned clay, with which it must have been in contact for long periods. Further, that the water originally combined with the CEMENTS, ETC. 101 lime has been entirely eliminated during this process of recarbonation ; and this stage passed, the amor- phous carbonate of lime seems to have been gradually transformed by the joint agency of water and carbonic acid into more or less perfectly crystalized deposits or concretions, by virtue of whicli its binding properties must have been very considerably augmented. Messrs. Abel and Bloxarn assign, as one of the causes of the hardening of mortars, the formation and subsequent crystal ization of the carbonate of lime. Stinde proposes the silicate as a very useful cement, by mixing equal parts of oxide of manganese and oxide of zinc, and making them into a thinish paste with the silicate of soda, which paste, quickly applied, sets very rapidly ; and by mixing the hydraulic lime to this composition, it is a cement which will resist permanently also the action of water and heat. “ Cement and Mortar of the Ancients. ‘‘We all know how enthusiastic some are in their praises of those ancient structures which have resisted for ages the ravages of time. They imagine that they are at liberty to draw conclusions which are not the most favorable to the architecture of the present time. Although they may be in a measure correct, it cannot be denied that such critics are too partial in their ad- miration for things ancient as opposed to things modern. We frequently hear the remark that some of the Koman mortars have endured for eighteen cen- turies the vicissitudes of time, while many buildings of now-a-days present, in a very brief period, the sign of quick decay; but they forget that these ancient 102 HYDRAULIC LIMESTONE, buildings constitute an exceedingly small fraction of the enormous number of those erected during many centuries in Egypt, Greece, Home and her provinces. They do not consider that thousands of temples, pala- ces, and private dwellings have been entirely de- stroyed. And what answer can they assign to the fact that the very complaints they indulge in were even more frequent then than now? Pliny asserts that the reason of the falling in of many buildings in Pome was to be attributed to the fact of the bad quality of the mortar. “ Still more important than this argument is that of Vitruvius, the architect of Augustus*. lie has left a work on Roman architecture in wdiich we find nothing that entitles us to place the architects of an- tiquity above those of the present time. Again, it has not been taken into account that a great part of the extraordinary strength of antique architecture is more the effect of time than the mechanical skill of the builder, or the virtues of his cements, as we propose to show hereafter. Pliny and Vitruvius both explain, to the best of their knowledge, what kind of materials the builders selected for their cements, and how they were prepared. The process was identical with the modern modus operandi. It is true that the old Ro- mans were particularly careful in the selection of ma- terials for their mortar, as well as in its preparation. They were aware that they must calcine the limestone, and mix it with sand, in order to apply it ; but did not possess any correct idea of the change which lime- stone undergoes in the process of calcination, nor of that which is the cause of the cohesive quality of mortar. CEMENTS, ETC. 103 “ Many centuries elapsed before these bicts ^Yere understood and explained. Black, in 1757, started the explanatory theory by the discovery of carbonic acid. A few years previous to this, Marggraf, the discoverer of sugar in beets, found the elements of gypsum, which was already employed by the Romans; and, in 170S, Lavoisier demonstrated the causes of the liardening of burnt gypsum when it is mixed with water. “ The ancients, therefore, put their practical know- ledge to the best possible account. As they were de- ficient in chemical knowledge, they were guided only by what observation taught them. Their chief care was centred in the exterior. In the selection of lime- stone. the color decided. Tlie white ones were con- sidered best, and the colored ones were seldom used. Those taken from the interior of the earth were pre- ferred to the stones wdiich were met with upon the shores of rivers. A law provided that the lime must liave been slaked three years before, it could be used. The same also prescribed the quantity of sand which must be mixed with the lime, mentioning also that crushed cherts imparted a greater strength to the mortar. Its preparation was, as it were, a state affair, the censors watching carefully over it. In spite of all this, it often happened, as Pliny states, that they did not attain the object in view. “ But in the advance of chemical science, the fact lias been established that a mortar can be prepared that, in the course of one or two ^’ears, will be as strong and durable as Roman mortar after the lapse of two thousand years. The builders of the ancients were not farther advanced than those of the middle ages. 104 HYDRAULIC LIMESTONE, The walls of the Bastile, for instance, were so strong that they had to be blasted away. This had likewise to be done in the removal of the remnants of a bridge at Agen, built about the year 1200 ; and the mortar of a bridge erected at Cahours in 1400 was even found to be considerably stronger than that of the antique theatre of the same city. “ The Homans were also acquainted with hydraulic cement. The merit of this knowledge is, however, considerably lessened, when we consider that the same is found in the volcanic districts of Southern Italy. A mere accidental observation, the same being, per- haps, mixed with sand instead of lime, may have led to its application. Says Vitruvius: ‘There exists a kind of dust which produces strange things ; it is found near Baja and the Vesuvius. When mixed with lime, it forms a mortar which not only imparts great strength to buildings, but also to water-works.’ “ The natural cement in question is a volcanic pumice-stone, like breccia, which is still found in the environs of Naples. At a less remote period of time, when the Homans invaded the valleys of the Lower Hhine, they easily recognised the volcanic nature of the Brohl Valley. Here, as well as amid the sur- roundings of the beautiful Laacher Lake, which lies like a jewel set in the midst of the long-extinct Hhenish volcanoes, they discovered another natural cement — the trass — in such considerable quantities, that the quarries which were opened at that time are still in existence. The use of hydraulic cement in ancient times could, therefore, have been only a limited one, as it was found only at the two places mentioned. Its artificial preparation was not under- 105 CEMENTS, ETC. stood. The solution of this problem was reserved for the investigating minds of the present progressive century.” “ Hydraulic Cement. This material is justly esteemed far superior to metal of any description for the lining of cisterns, the water-prooting of cellar-bottoms, and similar purposes. •A few directions for its preparation and use may not be out of place. To make water-proof work, it must be borne in mind that common lime must not be used at all; for on common lime water or moisture has an effect just the opposite to that which it has on the water lime^ rendering it soft and quite friable when dried ; whilst on the water lime the well-known effect is to make it perfectly hard. JSTo mixture of these two varieties of lime can, therefore, be made under water. Blit, although they do not act well together even under ground, they serve well in dry places, such as build- ings whose walls are of extra thickness ; and if proper care be taken, they will conjointly form a very com- pact and powerful cement. The fact that water lime shrinks when wet, while common lime, in the same state, swells, at once points out the manner of treat- ment to be pursued in uniting the two thoroughly. Thus, it is necessary to ascertain the per centage of shrinking of the one and increase in the other, as nearly as possible, before the proportion of one to the other can be determined, with a view^ to their intimate combination. Such experiments are the more neces- sary when we consider the great difference wdnch ex- ists in the quality of both kinds of lime in various lo- 106 HYDEAULIO LIMESTONE, calities. The simplest and'most effectual mode of testing water lime is to put several portions of different makes into small bags of flannel, and throw them into a basin of water. After three minutes’ immersion, take them all out at once, and squeeze each in the hand. Then take off each bag, and that which is best \% firmest^ and when thrown naked into the W’ater again, loses least of its outer coat. If none of them will bear’uncovering at three minutes, try four, five minutes, but this latter should be the longest test. The test for common lime is, on the contrary, the bursting open and evolving of caloric in a greater or less degree ; and the consequent action of the water will show, by its bubbles, the power of the lime. “ It is the per centage of clay contained in any specimen of lime that determines the solidifying pro- perty of the cement made from it. The best hy- draulic lime contains silex, lime and magnesia, or alumina. Its solidification is attributable to the for- mation of silicate of alumina and lime, or of magnesia and lime, which combines with water, and produces a hydrate excessively hard and insoluble in water. The hardening of hydraulic lime may, then, be compared to that of calcined plaster, which also combines with water to form a solid hydrate ; which calcined plaster, from the large quantities of it manufactured near that city, is commonly known as Plaster of Paris, A limestone containing thirty per cent, ot clay makes a quick-setting cement ; and we have in the United States the Uosedale and the Belleville cements, having forty and lifty per cent. They become exceedingly hard when plunged in water for from two to three CEMENTS, ETC. 107 minutes. Botli these cements, especially the former, have been used extensively by our engineers. Inferiority in the quality of hydraulic lime may be produced by the want of proper care during its manufacture, the stone being calcined at too high a temperature ; the double silicate in such case becom“ ing a sort of frii^ which does not hydrate in contact with water. “ As hj’draulic lime is expensive according to the distance of its transportation, we will here give the method of making an artificial hydraulic lime, accord- ing to the highly successful experiments of M. Yicat, a celebrated French engineer, and the author of a much esteemed work on hydraulic cement, who first pointed out the method to be adopted in its formation. It is prepared by stirring into water a mixture of one part of clay and four parts of cbalk ; these materials should be mixed by a vertical wheel turning in a circular trough, and made to flow out into a large receiver. A deposit soon takes place, which is formed into small bricks, which, after being dried in the air, are mode- rately calcined. Hydraulic lime thus prepared en- larges about two-thirds in volume when placed in water. Like the natural hydraulic lime, it can be completely dissolved by acids. This invention of arti- ficial hydraulic lime has rendered Yicat deservedly famous, as it has been in use for many years in the public works throughout France, and*was even em- ployed in the hydraulic masonry of the St. Martin canal. That it can be made in this country there is no doubt, as tbe argillaceous or potter’s clay required is to be found almost everywhere. The new cement which M. Sorel proposed to the 108 HYDRAULIC LIMESTONE, French Academy consists in the application of a basic hydrated oxychloride of magnesium, may unquestion- ably be improved by means of a silicated hydraulic lime and the bittern of the salines, which is a chloride of magnesium in a concentrated condition. Lime, sand and clay, when mixed with water, form the so-called composition of a hydraulic cement ; they are fit to unite solid surfaces by hardening after a few days’ application, under water, by forming a combi- nation with the constituents of either surface. Walls and piers have been built for over one hundred years, and after being exposed under water have become harder and harder. This cement is also called Ko- rn an cement, because the natural materials are found in abundance in the Koman district where the tufas, puzzuolanas and trass, all products of volcanic districts, like the Pontine Marshes of Pome, and near Naples, are abundant, and consist of those elementary sub- stances. In the voltaic formations of the triassic pe- riod the marls or green sand, the curious nodular and lenticular concretions, the Septarias and Indus Hel- montii, of turtle shape, all found in argillaceous strata of the sedimentary rocks which are alternating with limestone beds, and all found in abundance on the English and French coasts and the United States, all of them form a silicious clay intermixed with’ lime, and are, therefore, the proper material for a hydraulic lime or cement, 109 CEMENTS, ETC. Injection of Silicates. While engaged in impregnating the soluble silicates into the porous stones, and carrying this operation into all organic and inorganic matter, the convincing proof was manifested that the hardening of these bodies are only owing to the decomposition of the silicates, effected by the slow action of the atmospheric carbonic acid and the gradual condensation of silica. This pheno- mena led to the observations that the natural silicates and all! ruinates, as well as other mineral species, were similarly formed in the moist way. This remarkable reaction of hardening porous bodies by silica proves, by geological observations, highly probable that not alone all the enveloped and crystal- ized minerals found in limestone formations, but also an endless variety of silicated and aluminated sub- stances found in nature, owe their existence to analo- gous causes ; that the flints, agates and petrifled wood cannot have any other origin, but that they are formed by the slow decomposition of a silicated alkali from the carbonic acid, either atmospheric or generated during the process. This fact is of the highest interest in the chemico- physical investigations, and is the key to the investi- gations of the formation of the natural silicates, even under many various circumstances, of the condensa- tion of silica by other bodies than the carbonic acid ; many experiments undertaken have proved the gra- dual decomposition as already stated, and in a great variety, of the formation of such as opal, quartz, and others depending, likewise, of the state of concentra- 6 110 HtBKArLiC LiMESTOKJIj tion of the original decomposed materials. The irides- cence of the opal, which disappears if exposed long to dry atmosphere, but revives if moistened in water or sweet oil, gives a beautiful example. Many important facts have come to light by the investigations made on hydraulic limes and artificial stones, which prove that a considerable quantity of potash is contained in the natural hydraulic and other cements ; the origin of which is attributed to the decomposition of the alka- line silicates by the lime, and this may be proved by the formation of saltpetre or nitrate of potash in the efflorescences of walls and earths in caves, called an eremacausis of substances which contain nitrogen, and form, therefore, ammonia, and in contact with porous substances undergo an oxydation and conversion into nitric acid, and at once is combined with the alkalies contained in the native lime occurring in the older formations, and was separated, under certain circum- stances, from the alkaline silicates found in those lime- stones — nitrate of potash the result. In general terms, nitre, or nitrate of potash, which is found in crusts on the surface of the earth, on walls and rocks, and in caves, is found in those localities in certain soils of Spain, Egypt, Persia and East Indies, especially in hot weather succeeding rains ; it is also manufactured from soils where other nitrates (nitrate of lime or nitrate of soda) form in a similar manner, and beds called nitra- ries are arranged for this purpose in many countries. Pefuse animal matter also, putrified in calcareous soils, gives rise to nitrate of lime, as we find it so frequently n cow and horse stables, and is then converted into nitrate of potash ; old plaster walls, wfflen lixiviated, afford about 5 per cent, of nitre. It is known that CEMENTS, ETC. Ill nitre requires for its formation dry air and long periods without rain ; the potash comes mainly from the debris of felspathic and lime rocks in the soil, or in *the cements, if they have been used for building walls, and the oxydation of the nitrogen of the air is pro- moted by organic matters, hence the nitre is generally associated with azotized decomposed organic substan- ces. A nitre crust from the vicinity of Constantine, Algeria, afforded Eoussingault 85 per cent, nitrate of potash, with some nitrate of lime, soda and magnesia. In tlie Mammoth Cave of Kentucky, where the nitre is found scattered through the loose earth in great abundance, and was utilized during the war of 1812, also in the Mississippi Valley, in Missouri, many caves liave yielded the nitre winch was of great use to the secessionists of the late war, when Tennessee, along the limestone slopes and in the gorges of the Cumber- land table land, produced a large amount of salt- petre. The nitrate of soda, formed in a similar manner like that of nitrate of potash, but more particularly found in the dry pampas of Chili, where it is found at a height of 3,300 feet above the sea, contains beds of several feet in thickness, along with gypsum, common salt, glauber salt, and the remains of recent shells, indicating the former presence of the sea. Kuhlmann has proved bj" his investigations that the larger number of limestones from various geologi- cal periods contain both potash and soda, deriving their existence from various plants growing in a cal- careous soil, and has also shown the development of the efflorescence of the carbonates of potash, chlorides of potassium and sodium, which make their appear- 112 HYDRAULIC LIMESTONE, ance on the surface of walls from their construction, to which he was led by the fact that the alkaline salts in general are obtained in larger quantities from hy- draulic limes than from the lixiviation of air limes ; that the hydraulic limes contain mostly more alkali ; that it exerts much influence upon the quality of lime; and it has been ascertained by Yicat that the occurrence of the potash and soda is neither accidental nor less influential upon the proportion of the hy- draulic limes. It is presumed that the silicated lime- stone, and any fat lime mixed with clay by the influ- ence of potash or soda, are, during the burning, con- verted into double compounds, analogous to the nat- ural silicates, which are known under the name of zeolites, such as mesotype, stilbite, apophylite, etc., which all form hydrates, and lose their water of crys- talization by burning, and absorb it again on moist- ening ; one of the species of that class of mineral, such as the laumonite, which, when exposed for some time to the atmosphere, efiloresces and crumbles to pieces to the chagrin of the mineral collectors, but it is sufficient to confirm the remark just made regard- ing their constitution and similarity of the artificial silicates of lime and alumina. It is apparent that, in the hardening of hydraulic lime, a process takes place analogous to that of gypsum when hardening, and forming a hydrate. It may, however, be possible that the hydraulic limes be still formed without the pres- ence of potash or soda, and that the silicium or alu- minum in contact with lime fills the same office in possessing the property of binding the water, and to convert them in certain conditions to a hydrate. Hespecting the cement which is formed by the moist CEMENTS, ETC. 113 way, it is a fact that when chalk is brought in contact with solutions of alkaline silicates, an exchange of the acids of both salts takes place, one part of the chalk is converted into silicate of lime and the corresponding quantity of potash in carbonate of potash ; this ex- plains the true artificial stone, which has become, on exposure to the atmosphere, so hard, that, if the mix- ture contains a sufiScient quantity of a silicate, pos- sesses the property to adhere firmly to such bodies where it has been applied, the materials so formed with the silicate of potash or soda are analogous to cements without burning, and may be used for restor- ing monuments, etc. In the silification of artificial stones, the affinity of lime to the silica contained in the soluble glass is manifest, and shows the effect of the alkaline silicates on limestones ; and how the in- fluence of the atmosphere in the hardening of silicates or artificial limes is brought to bear through the at- mospheric carbonic acid by the separation of one part of silica in the silicates, and how the other parts of the silicate, when in close contact with a sufficient quantity of carbonate of lime, a lime silicate is formed. This acquired knowledge has produced numerous applications in industry ; it has proved that, by arti- ficial impregnation of mineral substances into the in- terior of porous substances, organic as well as inor- ganic matters are preserved, or silicified. The silici- fication of fine sandstone is easily effected by the mixture of 1 part of liquid silica, and 2 parts of fine sand, with the addition of a small quantity of chalk and white clay, all of which are wrought into a paste, and then formed into desired objects and exposed to the atmosphere for some time, and the finishing pro- 114 HYDRAULIC LIMESTONE, CEMENTS, ETC. cess continued bj means of hydraulic pressure and heating in hot chambers, the particulars of which have been indicated in a former chapter. It has been as- certained that always, if any salt insoluble in water is brought in contact with the solution of a salt which forms with the acid of the base of the insoluble salt a less soluble substance, an exchange takes place, which, although but partial sometimes, produces the forma- tion of double salts. This discovery led to a direct application that white lead, chromate of lead, chromate of lime, and the majority of the carbonated metallic salts, are suitable for silicification. THE SILICATE PAINTING ON STONE, Stereo-Chromic. The 1136 of the brush in the application of colors has so far been but partially accomplished. The sub- stitution of the potash or soda silicate for the fixed and volatile oils with mineral colors, has at first been at- tempted bj^ trituration of white lead with the liquid silicate. It has been found that a transformation of the white lead takes place the moment they come in con- tact together, which is so rapid that no time is allowed to transfer the paint into the brush. In order to make this paint more suitable, and to prevent a kind of de- composition, it was found advisable to add a large portion of the sulphate of baryta, artificially prepared, as this paint operates but slowly on the silicate solu- tion. It appears that this baryta may be used with more advantage by itself, as it unites perfectly with the silica, and a^^pears to form a chemical compound, but a disadvant5:ge presents itself in forming but a half transparent color, which does not cover well, and the addition of o;ide of zinc is therefore recommended, which agrees veil with the paint in connection with baryta and silica; this application has produced very satisfactory remits, forming a cheap white paint, which can be eisily transferred with a brush. Many niinerd colors, mixed with white bases, pro- 116 SILICATE PAINTING ON STONE. duce such difficulties on account of their drying too quick, others too slowly, according to the behavior of the bases to the soluble glass. Many combinations retain the alkali obstinately, and it was attended with many difficulties to apply the colors with the liquid silica; yellow ochre, blue and green ultramarine, sul- phuret of cadmium, peroxide of manganese, the oxide of chrome, have proved to unite well with the silica. The painting on stone is much easier when silica has been used on the stone than on that where it was not applied, for the reason that the absorbing quality of the silica, serving a binding material, withdraws it from the color, and it is therefore very advisable to apply several times the liquid, and exposing to the atmosphere before applying the paint. A single silicifi- cation of the wall is indispensable on the painted coloring, which is done by preparing, as usual^ with the liquid silica, as other paints are treated. The soda silicate, used for painting on walls, is easily effected by the use of the syringe. The painting on walls is attended with some difficulty likew/se, for while that on stone remains unaltered, the wood is apt to shrink, or to crack, and many woods will not easily take the paint, and even change they physical appearance, becoming darker; oak wood assumes the appearance of an old wood, and only ti^ white and hard woods, such as the ash and maply^ woods, will take up the silicate painting. Another dfficulty takes place in painting on wood, that it peelsoff, if applied too thickly. A weak solution of 1 paic silica, of 28° B. to 5 parts water, either alone or iombined with other bodies, is recommended. The new art of painting— Stereo-clromic— derives SILICATE PAINTING ON STONE. 117 its names from two Greek words, crepeoff, fast, or per- manent, and from the color, and has been introduced as a substitute for fresco painting, and bids fair to be very extensively applied, and more than the encaustic painting, from the fact that the works exe- cuted by this art have given great satisfaction ; the inner halls of the new museum at Berlin have been painted by Kaulbach with panels 21 feet high and 24f feet broad, and are said to equal the oil paintings in freshness and vigor, and with that particular ad- vantage, that the paintings may be viewed or examined from a certain stand to do so, and that it may be applied on many grounds without the rough mortar being first used. An experiment was made to expose a painting for one year to the atmospheric air, to the sun, fog, snow and rains, and retaining during the whole time its freshness. An important circumstance, however, is the formation of the groundwork, for any neglect in that of the lower and upper ground mate- rially affects the beauty of the painting. In order to produce a uniform strong firmness, it is necessary to supply the soluble glass uniformly, so that it may be absorbed perfectly and uniformly. The walls must be well cleansed, in the first in- stance, when the mortar is laid on, and then a weak solution of the liquid glass is passed over it and left to dry. Clean washed sand or limey sand is then mixed with a very small quantity of burnt lime, and made into a paste and laid on the wall. The surface is made even by an instrument, and the upper layer re- moved which was formed on coming in contact with the air ; but the mass must be always kept moist during the whole operation. This rough mortar will G* 118 SILICATE PAINTING ON STONE. soon become dry, and may be rubbed off with the fingers, but it must not be left too long exposed to the air, for fear of its attracting the carbonic acid, whereby the lime would be too much carbonized. By the application of a solution of carbonate of am- monia a considerable hard consistency is produced, when the liquid may now be applied several times with a brush, but always at intervals, and enough to pene- trate into the mortar, and the liquid glass ought to be that made from soda, and quite clear. In all cases the liquid must be laid on by means of a brush, in order to produce a uniform impregnation of the same. When this groundwork, called the underground, is faithfully and carefully prepared, the upper ground- work which is to receive the painting may be com- menced with ; it does not differ much from the first operation. The sand to be used must be of fine grain, and well washed, as also the quartz, etc., (the lime sand,) which is obtained from marble or dolomite, finely powdered, are to be used to the thickness of one line quite evenly, in order to obtain the necessary roughness on the surface indispensable to the process of painting. It may, perhaps, be necessary to use other substances before the application of the fine sand, in order to destroy any lime crust which might have been formed in the preparation of underground, and diluted phos- phoric acid is now recommended to be applied with a sponge or brush on its surface, for it forms then a phosphate of lime with the soluble glass, which binds well and does not injure the mortar. The ground so prepared, and well dried, is now impregnated with the liquid glass, the same as the first, and dilated also SILICATE PAINTING ON STONE. 119 with equal quantities of water, which is done twice, allowing sufficient time to dry between each impreg- nation. Wood may be painted by covering it first with a chalk ground, which must be thick enough to allow a polishing with pumice ; to chalk, glue or a little silicate solution may be added, as a binding material. Another difficulty occurs after the first has been over- come, in the oozing out of the carbonate of potash in damp weather, until the whole salt has been expelled, and many experiments have failed, and hydrochlorate of ammonia was first proposed in a weak solution, and an absolute insolubility of the color was thereby ob- tained, but chlorate of potash remained in this opera- tion, which destroys the gloss of the colors if not at once removed by repeated washing ; forced to resort to those few chemical agents, apt to fix the potash, which should enter as insoluble combinations in the color without destroying them, the perchloric and hydrofiuoric acids were resorted to. It is well known, that by washing with hydrofiuoric acid the den sit}" of the colors is much increased, and it was thought^ therefore, safe to use it, particularly in painting on glass, but only as a very weak solution. Hydrofluoric acid possesses the most remarkable property to dis- solve most oxides when in a concentrated state. The application of the weak solution of hydrofluoric acid, either for fixing the potash in painting and in silicifi- cation of limestone, was mainly calculated for such case where a silicate has been used with an excess of potash ; and in hardening of soft and porous limestones by a partial conversion into a lime silicate, it was found very expedient for fixing the potash, and making 120 SILICATE PAINTING ON STONE. sure the insolubility to moisten, at first with a weak, and then strong solution of the hydrofluoric acid, the stones when the potash oozed out. The acid, however, penetrates the stone and produces an insoluble com- pound ; in other words, it fixes the soluble potash, and produces an insoluble compound. Through this dis- covery hydrofluoric acid was found a very useful application in the fluosilicated lime. If brought in contact with lime, hydrofluoric acid is capable of dissolving it considerably without pro- ducing an immediate precipitate of calcium, or a separation of the silica; but at a certain state of satu- ration any addition of lime decomposes entirely the hydrofluoric acid, and so much that not a trace of these bodies can be discovered in the fluid. The same results are obtained by the carbonate of lime, instead of the caustic lime, and that silicium and fluor are produced in the limestone, which hardens but slowly, and it is therefore simply a fluorsilicon that produces the hardening of the lime. The effect of the hydro- fluoric acid on gypsum is also produced in both mixing, the surface of the gypsum is considerably hardened. If, however, the acid is used in excess, the gypsum is covered with raised pustules, which owe their existence to the formation of bisulphate of lime, because sulphuric acid does not act as well as the car- bonic acid in the treatment of limestone ; a fluor- calcium, mixed with soluble glass, may be used as a paint, or paste, or a cement, or any coating of other substances, and becomes so hard and weatherproof that neither soda nor potash will detach from the cumbination, and will remain dry. SILICATE PAINTING ON STONE. 121 Painting on Metals, - Glass and Porcelain. Silica painting adheres strongly on metals, pro- vided care is taken to keep the substances some time from the contact with water. The most durable paint is produced on zinc, also on porcelain and glass ; the colors assume a semi-transparency if painted on glass, and no doubt afford much inducement for its use. The sulphate of baryta, artificially prepared, com- bined wfith silicate, applied to glass, makes a milky white appearance, and is very beautiful, as it incor- porates very intimately with the silica, so that after the lapse of a few days the paint cannot be removed even with warm water. If this glass is exposed to high heat, (6° Wedgewood,) a fine white enamel is formed on the surface, which will compare well with the oxide of tin, and is much cheaper. Ultramarine, ’oxide of chrome, if converted into enamels, form a prolific source for the new art of painting. It is not quite necessary that a chemical combination should be produced in all these colors, if they only adhere strongly and produce the silicated cement, which has become hard by its fine division and easy admission of air. Emery, bloodstone, and peroxide of manganese, if finely powdered and prepared with a concentrated solution of soluble glass, produce cements of extraor- dinary^ hardness, resisting the effect of heat complete- ly, and become perfectly insoluble in water. For the production of an indestructible ink, soluble glass has been used and obtained by mixing finely burnt lampblack with the liquid soluble glass. Bra- connofs ink is prepared by decomposing leather in 122 SILICATE PAINTING ON STONE. caustic potash, and adding to the black mass the liquid soluble glass. A decoction of cochineal mixed with the liquid soluble glass, produces a red ink, resisting completely the action of chlorine and all other acids. Stereo-chromig for Easel Painting. The basis for this class of painting may be made from plates of burnt, porous clay ; it is first impreg- nated sufficiently with liquid soda glass. These plates may be three-fourths of an inch thick ; after one or two applications they become as hard as any stone ware ; they are very suitable for painting ground. The lithographic stone makes a good base for easel painting ; a thin coating of liquid glass mortar will produce a good’ base, and it may be first moistened with phosphoric acid, which assists much to absorb the colors with the liquid glass, and to make them fast. The colors to be used for this class of painting ought not to be chosen which decomposes the liquid glass, such as contain strong acids, nor those from organic substances. Burnt oxides are better than raw oxides, vermilion becomes brown, and at last black ; cobalt blue becomes clearer by the liquid, and the yellow ochre becomes darker. All colors ought to be properly prepared to make them fit for the silica painting, such as the great variety of oxides ; many of which, not containing much oxide of iron, may be suitable, also chrome red, ultramarine, umber, baryta white, cadmium yellow, and many more, purposely made by some chemists, not containing free acid, which enter into a decom- posing chemical combination. SILICATE PAINTING ON STONE. 123 The permanent white, or artificial sulphate of barj^ta, is said to be the proper material for a white paint. It is obtained from the native minerals, heavy spar or sulphate of baryta, and witherite or carbonate of baryta. The manufacture of the new paint is efiected by the reduction of the native sul- phate to a chloride of barium, or dissolving the native witherite in hydrochloric acid, and then adding either sulphuric acid or glaubersalt; the artificial sulphate of baryta is found in a condition of extreme fineness and purity, possessing a fine lustre, and susceptible for producing a fine white paint, which is the best substi- tute for white lead and zinc white, is not subject to tarnish or become brown in parlors like white lead, which is attacked by hydrosulphuric acid, and forms, when combined with the liquid glass, a slow but inti- mate combination, and is likewise used under the name of blancfix for card-makers, paper-stainers and paper collar manufacturers to a very large extent. It may also be considered in point of importance, if com- pared with that of white lead, not having a dilatory effect upon health as the latter. If mixed with the soluble glass it obviates the odious smell of linseed oil and spirits of turpentine. If it is mixed with dexter- ine, starch, or other binding material in connection with the liquid silicate of soda, its applications may be multiplied to any extent. The artificial sulphate of baryta is largely manufac- tured on the continent of Europe; in the United States it has so far been manufactured in New- York by a few chemical establishments for card makers, but not yet for the purpose of substituting it to white lead. SILICIFlCiTION OF WOOD. A PROTECTION AGAINST CoMBUSTION, INFLAMMABILITY AND Dry Rot. Wood, and all other organic combustible substances, may, to a great extent, be preserved against that great element, the fire, by the proper application of the liquid silicates. Still it requires much skill, experience and proper management to subdue totally this wonderful element when brought to its full power. There are many instances on record to prove either a full, or at least partial success in arresting the progress of a con- fiagration by the impregnation or coating of combus- tible bodies with many substances, such as possess incombustibility, whether liquids, gases, or materials which possess the properties of generating gases, that will withdraw or sulfocate the surrounding atmosphere, such as the oxygen gas, and thereby arrest the progress of the flames. Many chemical agents have been from time to time proposed to effect this object ; such as salt, chloride of lime, and, latterly, carbonic acid in its gaseous and liquid form, and many metallic salts have proved but a partial success in the prevention of decay . or dry rot of wood. The soluble glass is one of the first materials which have been successfully employed in arresting conflagration, and as far as 1823 this mate- rial was recommended in the construction of the Mu- nich Theatre, where 465,000 square feet of timber SILICIFIOATION OF WOOD. 125 surface were treated with a coating of the liquid solu- ble glass, and in 1830-31 and ’32 the author per- formed many experiments in the Brooklyn Navy Yard, partially as a protecting agent against fire, as also against decay of the woody fibre. Small square blocks of wood, after having been impregnated with the solu- ble glass, and sailcloth, writing paper, parchment, etc., were exposed for some time to the flame of a gas lamp. After the lapse of an hour, all these substances were found to be charred, but not consumed. It is proved that the liquid soluble glass produces a perfect ad-- hering, permanent covering which, when properly laid on, suffers no damage from the atmosphere. For coating the wood, etc., a pure solution of the liquid glass is required, otherwise it will peel off, and it is best not to use it first in a concentrated state, as it will not be able to penetrate into the pores, whereby the atmosphere must be expelled, and even five or six applications may be made in intervals of twenty-four hours. Although this process renders good services, it may be improved by the addition of other pulver- ized substances, wherein the soluble glass acts as the binding material, the coating assumes a better body, is stronger and more permanent, and if exposed to the fire, a crust is formed ; such, for instance, are bone dust, clay and chalk mixed together, a lead glass, etc. ; common clay, one-tenth of the quantity of silicate of soda, was successfully used with the liquid glass in the Munich Theatre. If applied on linen or other organic textures, the mere coating or dipping is not sufficient, but a surface between rollers must be resorted to, in order to produce a full absorption with the pores ; these stuffs may then be rolled up, but not folded. 126 SILICiriCATION OF WOOD. Building timber, rail-road sleepers, and other simi- lar materials, have been treated in the manner just described, and were protected fully against fire and dry rot. The author proposed a combination of the liquid glass with the following substances, intended as de- composing agents by chemical affinity, and producing in the cells of the vegetable fibre the various min- eral and metallic salts which are altogether insoluble in water, alkalies and acids, and he extended his ex- periments on the uses of lime, chalk, gypsum, cop- peras, etc. His process of treating ship timber, sleepers, cross-ties, roofing shingles and other ^ wood blocks was the following : 1. The materials to be treated were put in steam boilers and exposed for four hours to a pressure of hot steam, (or 300° F.,) then withdrawn from the ket- tles and dried. Alkalies and acids, such as hydro- chloric, have been since recommended for the purpose of abstracting color and albumen existing in the cells of the woody fibres, which, however, is accomplished by steaming. 2. In a solution of silicate of soda while hot, the materials to be treated are thrown and kept there for twenty-four hours, which will give ample time for the liquid to enter into the open cells while hot. 3. A large vat, containing either lime water, solu- tion of copperas, or blue vitriol, white vitriol or gyp- sum, finely powdered, and thrown into hot water, or finely powdered chalk of 1 pound to 10 gallons of water; the proportion of metallic salts is but one- quarter pound to the gallon of water. The woods are SILICIFICATION OF WOOD. 127 kept in the vats for another day, and then taken out, dried and ready for use. Coal tar, and the other products of dry distillation from tar and peat, have been recommended by Krieg as far back as. 1858, under the name of Creosote-car- bolic acid, which was then considered a waste product, and in its raw state having a specific gravity of 1.02 to 1.05^, and yielded from 20 to 30 per cent, of the tar; it was well known to possess the property of pro- tecting wood against decay. This chemist combined with the impregnation of woods, etc., the soluble glass and the creosote-car- bolic acid, for the reason that the latter precipitates the soluble silica as an insoluble substance while it is soluble in an alkaline lye. He proposed to expose the woods for three-quarters of an hour to a temperature of 300° F., and then drying them thoroughly. The woods thus prepared showed an increased weight of 6 per cent., and a lacquered surface, while in the inside the pores were filled with an insoluble precipitated silica. For effecting a still more perfect success is to fix the creosote on the woody fibre from the alkaline solu- tion, by diluted sulphuric acid, or by a solution of copperas, (sulphate of iron,) whereby the sulphate of soda thus obtained may either be washed out, or oozed out, the creosote-carbolic acid combines stronger with the woody fibre, and the impregnated woods may be considered safely protected against fire or rot. This process just described, deserves the serious at- tention of the various companies established for the last five years in the preservation of wood by carbolic 128 SILICIFIOATION OF WOOD. acid, tar, etc., by combining the soluble glass with their process, as we have described. Since the introduction of rail-roads, not quite 50 years, many men have been engaged in chemical ex- periments upon the cross-ties and sleepers, which, after being laid down for a few years, undergo the de- cay or rot, and have to be renewed, which causes great expense to the companies. Kyan, Burnett, Laboucheri, and many other chemists in all countries where this evil existed, proposed remedies; the subli- mate, chloride of zinc, pyrolignite of iron, all had their advantages and disadvantages ; of late, borax, alum, rosin, carbolic acid have been introduced. Wooden Hoof Shingles. One of the most valuable applications of the soluble glass may be recommended for shingles and wooden roofs of farm-houses in the country and near rail-roads, where the sparks of the locomotives have frequently caused conflagrations and destruction of property. The operation is quite simple, and the expense but trifling ; the process has already been described, but it may be still more simplified in the following manner : After the steaming of the shingles in boilers or in tanks, where steam of 250 to 350° is led into them, they are dried and thrown into a weak solution of liquid silica, standing about 25° B., in which they are left for twenty- four hours, when they are taken out and exposed to the air. Before they are quite dry, a weak solution of chloride of calcium is thrown over them or sprinkled over them with a broom. When SILICIFIOATION OF WOOD. 129 quite drj they are fit for use. They will uot burn nor be ignited with the sparks ; if exposed to a direct fire, will not light in a surrounding fire. An intense heat of long duration may char them on the surface ; they are, however, quite safe from any inflammation. The Preservation of Wood by Immersion. The processes for the preservation of wood may be divided into three groups, namely : processes by im- mersion ; processes by pressure in closed vessels, (which are exclusively employed for dry wood,) and processes founded on the displacement of the sap, (which are only employed for green wood.) In the present article we shall describe the methods by im- mersion. Attempts to impregnate wood by the method of immersion were the first experiments undertaken. As early as 1740, Fagol, a Frenchman, tried to im- pregnate wood with alum, sulphate of iron, and vari- ous other substances, in solutions of which he im- mersed it for several days. In 1756, Haller recom- mended vegetable oil for the same purpose. In 1767, Jackson indicated the use of a solution of sea salt, to which sulphate of iron and magnesia, alum, lime and potassa were to be added. In 1779, Pallas proposed to mineralize wood by dipping it first in a solution of green copperas and afterward in milk of lime. In 1830, Kyan, in England, tried to preserve wood by simply immersing it in a solution containing two per cent, of bichloride of mercury. Hot long since, ex- periments were made in France and Germany with a large number of rail road ties, by keeping them several 130 SILICIFIOATION OF WOOD. Lours in a solution containing 1.5 per cent, of sulphate of copper, at a temperature of 160° Fahr. This pre- paration is, however, altogether insufficient for the preservation of fir or pine wood, and in general for light woods which contain a large amount of nitro- genous substances ; but it seems to increase considera- bly the durability of oak. The wood is thus*^ sur- rounded by a very thin coating, which is not liable to decay nor to the attacks of insects, and which retards the alteration of the inner parts. These are, however, not iinpregnated at all by the antiseptic liquid ; they preserve their germs of putrefaction, which develop the easier the more the injected surface is removed, whether by friction, blows, or the driving in of nails. The decay commences then at the denuded points, and propagates itself toward the central parts. Decay of Wood and Processes for Preserving it. According to the experiments which were made by De Saussure, in the beginning of this century, it would seem that the decay of woody fibre was exclu- sively caused by the action of air and water. On ex- posing moist wood to the action of oxygen gas, he found that, for every volume of oxygen absorbed by the wood, one volume of carbonic acid was disengaged. It is now conceded that it is the hydrogen of the fibre which is oxydized at the expense of the oxygen of the atmosphere, while the carbonic acid is solely formed from the elements of the wood, or that the process is simply a separation of a portion of the carbon of the wood by direct oxydation ; and it would seem, from the experiment mentioned, that the first and only SILICIFICATION OF WOOD, 131 cause of the decay of vegetable tissue must be ascribed to the affinity of oxygen for the elements of the latter. Such cases of slow decomposition have indeed also been distinguished by the name eremacausis^ a term composed of two Greek words, and meaning to burn by dt3grees. The above explanation, however, scarcely holds good in all cases; it is now known that, in dry air, woody fibre may be preserved without decaying for thousands of years ; and, under water, in certain con- ditions, it appears to be equally durable. One must, therefore, look for some other cause to explain the transformation of vroody fibre. Such a one presents itself in the fact that, when wood is exposed for some weeks to running water, or if it is boiled in water and afterwards dried until the original weight is restored, it is rendered thereby considerably more durable. The cause of the transformation in question must, therefore, be sought in a substance which is removed by the dissolving action of water in the experiment mentioned. By further investigation, this substance is found to consist of the albumen of the sap, which is distributed throughout the cellular tissue. Like the animal albumen, as the white of eggs, which it closelj^ resembles both in properties and composition, the vegetable albumen is exceedingly liable to decomposi- tion. In this state it acts like a ferment, inducing the decay of other bodies, according to the physical law propounded in another application by Laplace and Berthollet, namely, that a molecule set in m'o- tion by any power can impart its own motion to 132 SlLIClFICATlON OF WOOD. anotlier molecule with which it may come in con- tact. Among the bodies most prone to decomposition is the sugary element, which is first dissolved. Then the growth of fungi generally begins, and the putre- faction proceeds step by step. It may, therefore, be considered that the spontaneous decomposition of the vegetable albumen is the primary cause of the decay of wood. It is, indeed, found that those kinds of wood which contain the smallest quantity of albu- minous matter and amylum are the most durable. Especially is this the case with a certain tree of the acacia tribe, the locust, and the cedar, which resist decomposition in situations where all other kinds of wood soon decay. In order, then, to find out whether a certain kind of wood is especially fitted for building purposes, the quantity of albumen present in the fibre should be ascertained by analysis. M. Payen recommends, for this purpose, to digest the wood in a dilute solution of caustic alkali — this soda, or potassa — which has no action on the woody fibre, but only dissolves the albu- men. Hence the quantity of the latter may be esti- mated by washing, drying and weighing the wood after the experiment has been made. Hipregnation of Wood by Pressure. The apparatus now used in France for the satura- tion of timber with preservative agents is described as follows : It consists of a cast-iron cylinder, which is connected by means of a tube with a condenser. Both are placed in a vertical position. The operation is SILICIFICATION OF WOOD. 133 begun by introducing the timber into the cast-iron cylinder, together with the preservative material. The latter, however, is not altogether to rise to the entire height of the stem. The receptacle of the wood is hereupon closed, and connected with the condenser. A vacuum is then produced in the latter, which is accomplished by introducing alternate steam and sprays of water into it. After this the stop-cock of the tube connecting the two cylinders is opened, when the air passes from the receptacle into the condenser. This operation is repeated until the pressure in the cylinder is less than fifteen decimetres. The same is kept up for several minutes, in order to let the air of the timber have time to escape. The connection be- tween the receptacle and the condenser is finally closed. A pump is then set in motion, by means of which the preservative agent is made to penetrate the pores of the vegetable tissue, until the pressure stands at that of ten atmospheres. This is maintained for various lengths of time, according to the nature of the wood and the liquid, but six hours are generally sufficient. After this the air is gradually allowed to enter, while the preservative liquor is left to run away. “ The capability of wood to sustain the strain to which it must necessarily be exposed, especially when moving over it at high velocities, has been satisfac- torily proved by the experience of the Great Western and other railways, where continuous longitudinal sleepers of wood have been employed, and experience has shown that the solidity of the road is much greater than when the iron rails were attached either to stone locks or transverse wooden sleepers. In 134 SILIcmCATION 05’ WOOD. proof that wooden rails cut from beech will hear the wear and tear of trains passing over it, it is well known that beech cogs have proven to last eighteen to twenty years when working in gear with an iron wheel. The rails on the Yauxhall line were prepared by Payne’s patented process for preventing dry rot and decay of timber. Scotch fir, if subjected to pressure, will crush at ten tons, while beech (the wood recommended for railways) will bear a pressure of eighty -two tons before it begins to yield. “ Experience having confirmed the capability of Scotch fir to withstand the traffic of twelve engines per day for seven years, without any visible wear, it wmuld be difficult to say how long the rails cut from beech, sustaining eighty-two tons pressure, would last. Some of the impediments with which rail-roads have to contend are the- undulations of the country, and the necessity of diverging from a right line in order to obtain the traffic of important towns. These obstacles can only be overcome by an outlay of capital, in making the required excavations and embankments, or by the oftentimes ruinous system of tunnelling ; and after all, inclines of greater or less gradients are una- voidable, and prevent the line working economically. Curves on iron rail-roads are highly prejudicial, espe- cially if the radius be small, as the wear and tear be- comes proportionably increased.” Timber Kot and Seasoning. It is generally supposed that the rotting of timber is merely induced by the action of the oxygen of the air. From analysis made of sound and decayed oak, SILICIFICATION OF WOOD. 135 it has been shown that for every two equivalents of liydrogen oxjdized by the air, one equivalent of car- bonic acid had separated. It may therefore be in- ferred that the decay or rot of timber does not arise from fermentation, but is rather a chemical process. Others admit that microscopical parasites of vege- table nature play an important part in the deca}^ of wood ; but consider tlie presence of albuminous mat- ter in the sap as necessary, wliich, according to them, must also be first in a state of decomposition before it allows the growth of those organisms. In order to throw light upon this most important subject, we pro- pose first to tabulate a number of well observed facts. Sound timber, when immersed in water, without ac- cess of air, will withstand decay for almost an un- limited time. This is proved by the piles upon which the dwellings on the Canaries rest, which were erected in the time of the Conquest in 1402, they being just as sound now as if they had been freshly felled. Roots of trees that have been submerged in marshes are rarely found decomposed. This is stated to be the case with the utensils discovered in the lake dwellings of Switzerland, Bavaria and Lombardy, which must be at least ten thousand years old. Hartig also de- scribes a cypress stem with over three thousand rings, representing the same number of years, which, though submerged, had only partially turned into brown coal. With respect to the action of the atmospheric air, it may be asserted that the same, even when moist, will not produce rot if the wood has been well steamed, or exposed to the action of running water for a sufficient length of time. In England it is customary to lay the 136 SILICIFICATION OF WOOD. timber destined for threshing-floors and wainscoating in fresh water for several weeks. When again dry, and not exposed to damp, such timber will endure for an incredible period of time. This tends to demonstrate the fact, that the substance which induces decay must be foreign to the timber it- self. This substance is the juice that is chiefly con- tained in the vascular tissue, which forms a link be- tween the bark and the wood. The composition of this sap varies according to circumstances, as the va- riety of the tree, climate, season, ground, etc. The following are analyses of the sap : In 100 Parts. Sap of Elm Tree. Vanquelin. Sap of Cow Tree. Solly. Dried Sap of Bark of Antiarin Toxicaria. Mulder. Albumen, S.06 {a) 16.14 Dextrin, • • • . 4.37 (6) 12.34 Sugar, • • • • 6.31 Resin, • • • • 20.93 Galactin • • • • 30.57 . . . Myricin, • • • . • • • • 7.02 Antiarin, • • • • • • • • 3.56 Organic Substance, (not determined,). . . . 0.10 • • • • .... Potassa with Organic Acid, 0.87 A • • • • . . . Carbonate of Lime, 0.10 • • • • .... Extractive Matter and Salts, • • • • .... 33.70 Water, 98.93 62.00(c) .... 100.00 100.00 100.00 (a.) Gluten and Albumen, according to Solly. (&.) Dextrin and Salt, (c.) Water and Butyric Acid. Remarks . — The Cow Tree {Galactodendron) is a native of the Cordilleras of Venezuela ; it furnishes, by incision, an enormous SILICIFICATION OF WOOD. 137 quantity of a white, thick liquid, which has the taste and some of the qualities of a real cow’s milk. The Antiaris toxicaria belongs to the same family as the former, namely, to the nettle-worts, and it is singular that it furnishes a most deadly poison, which has been the subject of the most harrowing stories. (Jussieu ; Elements of Botany) Unfortunately we possess only one analysis of a tree indigenous to North America; however, the same tends to show that the amount of albumen, if the non- determined organic matter must be considered as such, is exceedingly small; and with respect to the other trees, these analyses prove that the albumen does not constitute the chief part among the ingredients of the juice. How unjustifiable it is, therefore, to attribute, in every instance, the decay of timber to the albumen present in the sap, as if it was the only substance lia- ble to spontaneous decomposition, or affording the vegetation of fungi and lichens ! In regard to the amount of sap and air contained in the oak and poplar, we possess the following data from Count Rumford : Wood. Sap. Air. Oak, 0.39353 0.36122 0.24525 Poplar, 0.24289 0.21880 0.53831 The German botanist, Schacht, in all instances of decayed timber, has met with fungi and lichens. The destruction of timber by decay, after the same has been hewn, must, therefore, be considered as being produced bj^ similar causes which brought on the dis- ease of the vine, potato, mulberry trees, and other cul- tivated plants, which make the years U45, ’48, ’53, ’57 and others for ever painful to the memory. 138 SILICIFICATION OF WOOD. That the juice should be in a state of decomposition before being capable of generating those organisms seems doubtful, since this has not been found the case in other and well studied modes of fermentation. The morel, a species of mushroom, will also attack per- fectly sound wood. Hand in hand with the spread of the fungi continues the decomposition of the ligneous tissue. Access to moisture and air, as also a certain degree of heat, are necessary. In regard to the air, fungi require oxygen for their generation. When air- dried, steamed, or chemically treated and afterward dried, wood commences to rot, it is a sign that moist- ure has again penetrated; for it is scarcely to be ad- mitted, that in all these cases the sap had been entirely removed. Timber decomposes the easier the more sap it contains ; and if green trees are hewn when the ves- sels are overflowing with juice, one may look with cer- tainty for diminished durability of the timber. Tim- ber is not always the more durable the more dense it is, but rather when the even fineness of the grain con- tinues to the pith of the stem. The Roman historian, Pliny, considers the resin- iferous woods as the most durable. Indeed, nature shows that this is frequently the case. The resin ifer- ous red and white pines of Oregon and California are considered first-class ship timber, so much so that entire vessels have been constructed from the denser qualities. The yellow or long-leaved pine, in dry sit- uations, is extremely durable, and is preferred to oak of any kind, where a lighter, yet solid wood, is re- quired. The white or northern pine, which grows abundantly in every northern State of the Union, from Maine to Minnesota, reaching often to an altitude of SILICIFICATION OF WOOD. 139 one hundred and eighty feet, with a diameter of six feet or more, is said to retain its properties as long as the veiy best description of oak. The proportion in which the woody fibre and water are to each other is very different. It varies accord- ing to the degree of dryness and the nature of the wood itself. According to Schubler and Neuffer, we have for newly felled v/oods the following table : WOOD. WATER. Hornbeam, Willow, 26.0 it Sycamore, 27.0 it Asb, 28.7 it Bircb 30.8 a Oak, 34.7 it Pedicli Oak, 35.4 it White Fir, 37.1 it Pine, 39.7 a Red Beech, 39.7 a Alder, it Asp, 43.7 it Elm, 44.5 it Red Fir, 45.2 « Lime Tree 47.1 a Italian Poplar, 48.2 a Larch 48.6 a White Poplar, a Black Poplar, 51.8 ti The amount of water in wood, after one year’s dry- ing in the air, ranges from 20 to 25 per cent., and when perfectly air-dry, as it is called, it still holds from ten to fifteen per cent. The specific weight of newly felled timber ranges from 0.85 to 1.05 ; that of air-dried timber from 0.45 to 0.75. The weight of one cubic foot of newly cut 140 SILICIPICATION OF WOOD. native timber would thus range from fifty to sixty- five pounds, while that of seasoned wood would vary from twenty-eight to forty-seven pounds. The total expulsion of moisture by means of air-drying, accord- ing to the experiments of Rumford, takes place only at 280° Fahrenheit. But even if thus completely dried, and then exposed again to the atmosphere, it absorbs nearly five per cent, of water during the first three days, and continues to absorb until it contains from fourteen to sixteen per cent., after which it be- comes very hygroscopic, losing or absorbing water according to the state of the atmosphere. The drying of lumber in confined rooms by means of hot air, or steam and air alternately, is now largely practiced, and the more on account of the economy of the method than on account of its yielding a supe- rior product. In some cases,* the wood, before being exposed to artificial heat, is subjected to a longitudinal pressure, in order to rupture the cells in which the moisture is confined, to the end that it may escape more freely upon the application of heat. It is claimed that the wood is thus rendered more valuable for nearly all the purposes for which it is used, but particu- larly for the hubs, spokes and panels of carriages, etc. Pkeserving Wood. The preservation of wood constitutes one of the most important questions with which applied chemis- try has to deal. It has been ascertained by careful statistics that the wooden structures alone on the farms of this country cost over one hundred millions of dollars every year, while the sleepers on the rail- SILICIFIOATION OF WOOD. U] waj^s cost twenty-fi\^e millions during the same period of time. If the duration of all this wood could be doubled, it would save the country twelve and a half millions every year in rail-road ties, and fifty millions in fence and farm buildings. At the same time, our woodlands are being cut down with fearful rapidity. This fact assumes great importance, when we reflect that there exists a most intimate relation between the climate of a country and the extent of its forests. This becomes at once evident, when it is known that the springs of rivers do not issue from subterranean reservoirs, but consist chiefly of collections of atmos- pheric precipitates, rain, dew and snow, which have percolated from higher levels. Rainless regions are always deficient in woodland, and there are innumera- ble instances where vast and fertile tracts of land have been changed into barren and unhealthy deserts, simply because they have been stripped of their forests. Therefore, in lengthening the duration of wooden struc- tures, we, at the same time, prevent the destruction of our forests, thus leaving to the coming generations the same resources which we have inherited from our forefathers. The process may be briefly described as follows : The wood to be treated is placed in an iron chamber, which is connected with a still containing coal-tar. To the latter heat is applied, until the contents have reached the temperature of 600 ° Fahr. The inventor not only claims that the thus impregnated wood will be completely protected against the moisture of the atmosphere, but also that it is rendered “ nearly as indestructible as granite.” In order to comprehend this process, it is necessary that we should examine 7 * 142 SILICmCATION OF WOOD. the nature of the products which are given off in heat- ing coal-tar, and the changes which they produce on entering the pores of the woody fibre. Coal-tar con- sists, as is well known, of a number of substances — acid, basic and neutral ; of the latter, some are liquid, some solid. In subjecting tar to distillation, the first products given off are ammonia and probably also permanent gases; then water is evolved, together with various ammoniacal substances, and a brownish oil of a noxious smell and of less specific gravity than water. The latter is associated with the so-called light oils, the portion in which they are contained being generally gathered separately in tar distille- ries. They amount to from five to ten per cent., and when the temperature has reached 320° Fahr., it may be concluded that they have passed over. The oils distilling at a later stage contain large quantities of naphthalin and paranaphthalin, both solid hydrocar- bons, of which the first appears at about 400° Fahr. They are often present in such quantities that the condensed distillate assumes the consistency of butter. Carbolic or phenic acid is given off a little earlier, but the giving off of naphthalized oils continues up to 550° Fahr., when a resinous, yellowish product ap- pears, which can be easily kneaded between the fingers. The remainder is the black, pitchy mass, used in the construction of Nicholson’s pavement. Among the various substances here enumerated, the phenic acid alone is that to which any preserva- tive properties can be ascribed. It has been deter- mined that tar from cannel coal contains seven per cent., that of Staffordshire coal four and a half, and tar from Newcastle coal two and a half per cent, of SILICIFICATION OF WOOD. 143 this acid. The average quantity of phenic acid in coal-tar would therefore be less than five per cent.; moreover, it is never found in the free state, but always in combination with bases, whereby its effi- ciency is greatly impaired. Again, being soluble in fresh and salt water, it is easily and rapidly washed out, finally leaving the wood as completely liable to decay, as well as to destruction by insects, as it was before treatment. These facts are sufficient to justify us in drawing the conclusion that the vapors of coal- tar are not efficient preservatives. This fact was, indeed, particularly reported upon by the Dutch Government engineers. They dis- covered that after thirteen months’ exposure, piles which had been creosotized under Mr. Bethel’s special superintendence, were found so completely free from the impregnating material that the teredo navalis had eaten up and destroyed these to a thickness of one inch and a'quarter. Tlie same fact was also reported by Mr. Stevenson, the famous English engineer, in the case of the piles and wood-work on the Woolwich side of the Thames. The dead oil had been completely washed out, and the destruction of the wood by decay and by worms was proceeding at such a rate, that Mr. Stevenson expected to see the piles totally destroyed before the expiration of three years from the time when they had been impregnated. Again, for many very important purposes this pro- cess is inapplicable, on account of the intolerably ofiensive smell of the dead oil and other products of the dry distillation of bituminous substances. In a pamphlet before us, it is stated that there is no record in the books of any thing like this process 144 SILICIFIOATION OF WOOD. having ever been known to the world prior to its dis- covery by Mr. L. S. Eobbins. It is claimed to be as new as was the sewing-machine or the telegraph. We presume that Mr. Eobbins did not know of the process patented by Frantz Moll, in England, in 1835, which is as follows : The wood is placed in a close cliamber, which is connected with one or more stills. The operation of impregnating is begun by heating the inside of the chamber by a steam pipe to a tem- perature sufficiently high to maintain the vapors con- taining the phenic acid in a vaporized state. But be- fore these are introduced, the watery vapor from the damp timber is allowed to escape, after which heat is applied to the still containing the light hydrocarbon oils, or the ‘‘ eupion,’* as the mixture was named by Moll. When it is thought that the timber has been sufficiently impregnated witli these vapors, the surplus is drawn off, and vapors from another still, containing the heavy oils, are admitted into the chamber. Fi- nally, boiling liquid creosote is introduced into the chamber by a pipe, in a quantity sufficient to cover all the wood therein. It will be seen that this process is substantially that of L. S. Eobbins, but was recom- mended in 1858 by Dr. Krieg, in connection with soluble glass, for the preservation of all wood-work against tire and rot. Wooden Eoof Shingles. One of the most valuable applications of the solu- ble glass may be recommended for shingles and wooden roofs of farm-houses in the country, and near rail-roads, where the sparks of the locomotives SILICIFICATION OF AVOOP. 145 have frequently caused conflagrations and destruction of property. The operation is quite simple, and the expense hut trifling; the process has already been described, but it may be still more simplified in the following manner : After the steaming of the shingles in boilers or in tanks, where steam of 300 to 350° is led into them for several hours, they are dried and thrown into a weak solution of liquid silica, standing about 25° 13., from which they are taken out and exposed to the air before they are quite dry, a weak solution of chloride of cal- cium is thrown over them or sprinkled over them with a broom ; when quite dry they are fit for use. They will not burn nor be lighted by the sparks if exposed to a direct fire — will not light in a surrounding fire. An intense heat of long duration may char them on the surface ; they are, however, quite safe against any infiammation. Street Pavements. As a rule, competent engineers express doubts as to the merits of the Nicholson, and of wooden pavements of all patterns. In the Nicholson structure the road-bed is of sharp, clean sand, of the proper thickness. A basis is then made by laying common boards, dipped in hot coal- tar, lengthwise on stringers of like material laid from curb to curb. The blocks forming the superstructure are of Southern hard pine, three by four, and are set on end in rows, crosswise of the street — the blocks before setting being dipped to half their length in a 146 SILTCIFICATION OF WOOD. bath of coal-tar. Between the rows of blocks inter- vene pickets of thin board set on edge, and leaving an opening between the rows of blocks of an inch or nearly in depth. This opening is filled with clean screened gravel, rammed down with a paver’s ham- mer, and an iron blade made for the purpose, and the surface is covered with hot coal-tar. The gutter ex- hibits its lowest point half a foot from the curb. The whole surface is covered with coal-tar sufiiciently boiled to.be tough and fibrous, but not brittle, upon which is sprinkled a layer of fine gravel and conimon sand. The Stafford pavement differs from the J^ichol- son, in the laying of large blocks prepared after the Seely patent, resting upon stringers, which in their turn may be supported by any specified road-bed. Provided the road-bed is sufficiently secure, say of strong concrete, and the upper deposit is made suffi- ciently complete, the Stafford pavement cannot but compare favorably with other wooden pavements, and, for simplicity, is quite superior to the Nicholson. The Stafford pavement appears, at the present mo- ment, to be the favorite one in the City of New- York, as a large contract is now carried out for the upper part of the city. Both obviate certain objections in surface way which pertain to the Belgian, in the wear and tear of vehicles and horses, and the noise or reverberation of wheels ; but both are inferior to the asphaltic road in these respects, while the asphaltic has one great superiority valuable as preventive of accident, to wit, the beating of the hoof of the horse is rendered very audible — audible above all other sounds — so as to be measurable by the ear in the matter of distance. This SILICIFICATIOW OF WOOD. 147 latter advantage can only be estimated by persons who have taken occasion to note the extent to which one fails into the habit of measuring the distance of a vehicle from any given crossing, by the ear; and one of the main liabilities to accident, occurring from wooden pavements, is the muffling or comparative muffling of the hoof beat. In this respect, in fact, any form of concrete pavement possesses material advanta- ges over either the stone block, which exaggerates the rumble of wheels and obscures the hoof-beat, or the wooden pavement, which reduces both in about equal proportions. In a word, a grave objection to the Kicholson pavement is the fact, tliat in just one respect it is a trifle too noiseless for the safety of pedestrians in crossing, especially iii these days when every driver seems to be possessed with the devil to run over some body. Again, in case of extensive conflagration in any part of the city, the wooden pavement might prove a dangerous ally by ignition, an instance of which has recently occurred in Philadelphia. Neither of the wooden pavements above named command the unqualified admiration of practical engineers as yet, though the test of use is the measure of merit in these . matters, and neither has been in use here sufficiently long to warrant the expression of an opinion. The Parisian system has, since 1854, manifested strong preference for the asphalt road upon the con- crete foundation. In 1854, nine hundred and sixty square yards of asphalt road were laid in Paris, and since then the use of the material has steadily in- creased, until at present it is ranked as well adapted for purposes of heavy traffic on the most frequented thoroughfares. Up to 1866, 96,000 square yards had 148 SILICIFICATION OF WOOD, been put down ; in 1867 the surface added was 54,000 in Paris proper, and 84,000 in all in the department of the Seine, making a total in thirteen years of 180,000 square yards. The contract of the Cie Gene- rale des Asphaltes with the City of Paris, covered at that date at least 96,000 square yards more, to be put down in 1868 and 1869. The ancient streets of Paris were without sidewalks, and were paved with large square blocks, with grades sloping from the sides to the middle, forming a gutter on the central line. Sidewalks began to appear in 1825, and in the same year the reversal of the surface, bringing the gutter to the sides, was introduced. In 1852 the system of MacAdam was applied to the old boulevards, and in 1858 this method was improved for heavy traffic by introducing margins along the sides, from two to four yards in width, paved with small blocks of Belgian porphyry — the germ of the sidewalk as now used. The first cost of asphalt streets is greater than that of Macadamized, while the cost of repairs is considera- bly less ; and, again, the first cost of the asphalt is less than that of the Belgian pavement, while the ex- pense of repairing is greater. The asphalt coating, one-sixth of a foot thick, is supported upon a road-bed of concrete, composed of ninety parts gravel to forty parts of mortar, about a quarter of a foot in thickness, and resting upon the compacted soil bed beneath. Pro- vided the requisites of thorough surface and under drainage have been observed, the asphalt roofing, being utterly impervious to water, the road-bed of concrete waxes harder and drier with age, and, once made, is imperishable. Pepairs are easy, and consist simply in cutting away the damaged roofing of asphalt SILICIFICATION OF WOOD. 149 and replacing it with new. As compared with the Belgian pavement, the liability to fall of horses being driven over the asphaltic road is 1 in 1,409 to 1 in 1,308 on the former, proving the superiority of the asphaltic surface in this respect — that is, in surety of foothold. The merits of the wooden pavement are its noise- lessness, its reduction of the mortality of horses, its reduction of the wear and tear of vehicles, and its effecting a utilization of the utmost per centage of draught force, and these are all merits to an equal de- gree of the asphaltic road, and may be made merits of any concrete whatsoever. The increased mortality in horses occasioned by the Buss and Belgian and. other stone pavements in this city, is estimated at 3,500 annually — an item of considerable importance in the discrimination between pavements for thoroughfares. As between the two typical structures, the Belgian and the Nicholson, from data already supplied, it may be estimated that, with the attrition of Broadway, the former would last fifteen years against a last of half that period in the case of the latter, if, indeed, the Nicholson can be regarded as equal to the necessities of Broadway at all. It is seen, therefore, that while the stone block (Belgian or Buss) is open to grave ob- jections on the one hand, the wooden pavements (Nicholson and Stafford) are open to equally serious objections on the other hand, on the score of lessened durabilit}^ The concrete pavement — the value of which has been happily settled in Paris — effects a ^ union of the better qualities of both, without the ob- jections appertaining to either ; and, as the minds of engineers and inventors are already beginning to turn 150 SILICIFIOATION OF WOOD. in this direction, notliing is hazarded in predicting that the ideal or coming pavement will be developed from the present crude concretes. The asphalt road, one triumph of concretion, the heton Coignet^ another triumph in a direction of equal practical importance, the attempts at concrete from inexpensive material in this country, all point to the hypothesis that the solution of the long mooted pavement problem is at hand, in the evolution of a concrete roadway com- bining the durability of the stone-block with the ad- vantages of the wooden superstructure. Valuable hints as to the constitution of concretes may be found in the reports of Messrs. Beckwith on heton Coignet^ and asphalt and bitumen as applied to the construc- tion of streets and sidewalks in Paris; and, in the way of American invention, the constitution of the Fiske concrete pavement, under the Hairm Burlew patent, may be studied, but has proved so far a great failure in Fifth Avenue, where the concrete had to be taken up again last winter. This pavement is com- posed of gravel, broken stone, cinders and coal ashes, (free from all foreign substances,) mixed in definite proportions with tar, rosin and asphaltum. The road- bed properly prepared, the composition is spread on in layers of moderate thickness, successively rolled with heavy rollers for uniformity and compactness. These layers form a sufiiciently strong roadway of from half to three-quarters of a foot in depth, and can be put down at an expense, per square foot, not ex- ceeding the expense of the asphalt road as constructed in Paris. It remains for years and attrition to test the practical value of this concrete; but, in general, it may be remarked, that it is heartily and highly SILICIFICATION OF WOOD. 151 commended bj thonghtfiil engineers as a step in the right direction. The sonorousness of the hoof-beat, as enabling the pedestrian to measure tlie imminence of passing vehicles, is an element of concretes over wooden pavements, illustrated in an eminent degree bj the asplialtic road, the value of which, as a preven- tive of accidents, cannot be over-estimated. A pave- ment may be too noiseless as well as too noisy for immunity in this respect, and by all means let the capacity of the concrete be developed to the utmost. The Commissioners of the Park have also developed some excellent roadways in their admirable system of earth roads upon a similar principle ; though in rela- tion to the Park, the problem has been less difficult of solution, no necessity existing to provide for the contingency of heavy traffic. In its capacity for the combination of all the qualities which experience has proved to be desirable in a roadway for large cities, the concrete must, therefore, be ranked as superior to either of its competitors, with some most important and indispensable improvements to be applied, and as embodying in itself the germ of the coming pavement in this city ; and the suggested reforms in the sewerage system having been carried out, attention may be di- rected to the production of an inex])ensive concrete, analogous to the asphaltic road. Various Systems Adopted for Poadway Pavemi:nts. A great variety of systems have been adopted for roadway pavements. The most convenient classifi- cation of them is into gravel compositions, broken 152 SILICIFIOATION OF WOOD. stone, plank, wooden block, cobble stone or pebble stone block and iron block pavements and tramways. The first attempts at pavements generally commence with the use of gravel. Roads thus made possess the advantages of cheapness of material and construction. In tlie Central Park, where there are probably the most perfect roads in this country, they have shown better endurance than those made on the MacAdam plan. Gravel roads, when properly constructed and maintained, are comparatively smooth and noiseless, besides affording excellent foothold for horses. The great objections to them are that they cannot be kept firm enough to afford easy draught for heavy traffic ; that they lack, in a high degree, permanence, and are constantly requiring repairs ; that they are difficult to keep clean and to drain properly ; the rapidly grind- ing and crushing to powder tending greatly to cause dust in dry weather and mud in wet weather ; and, lastly, that the best construction yet attained has failed to prevent them from washing* into gullies. Under the head of second composition pavements, may properly be included pavements formed by the combinations of several materials, such as the famous asphalt pavement of Paris, concrete, heton^ gutta percha, slag, cinder, and other pavements ; also, those formed according to the experiments of McUeil, partly of broken stone and partly of pieces of cast metal, laid on a sub-pavement of rubble stone. The asphalt pave- ment of Paris, so often recommended in newspaper articles, is really quite an imperfect pavement. It is generally formed on a foundation of MacAdamized road. Powdered asphalt is placed on the foundation, and stamped with hot rammers until it is very hard. SILICIFICATION OF WOOD. 153 and has a thickness of one or two inches. It is very pleasant and smooth to ride over, but requires most constant watching and repairing. It is slippery in wet weather, and excessively so at a freezing tem- perature. Pavements of Granite. Granite blocks, considered in every respect, form one of the most perfect pavements known. They are preferred, and almost exclusively adopted in London. The Puss pavement, the nearest approach to a perfect pavement yet constructed in this citjq has, in imitation of the Poman pavement,' a hHon foundation of six inches thick. The heton is composed of one part cement, to two and a half parts of broken stone, and two parts of gravel. On this foundation are laid hard granite blocks ten inches deep, ten to eighteen inches long, and from five to twelve inches wide. It is very durable, and yet, as shown in Broadway, this excellent pavement has most signally failed, the surface of the granite used polishing and afi*ording dangerous foot- hold. What is required, and this would give a perfect pavement, is the adoption of the kind of stone blocks used in London, which do not polish by wear, and present joints about every four inches. Another pavement is now being substituted here in an imper- fect manner. The blocks now used are of a coarser granite, twelve inches long, nine inches deep, and four inches wide, the courses running at right angles with the line of the street. What is known as the Belgian pavement was, until recently, the principal one in use in the old streets of Paris, and, as is well known, has 154 SILICmCATION OF WOOD. been quite extensively adopted in this city. This pavement has the advantage of cheapness, and, if well laid, of economy, tlie necessary and actual cost being a little over one-half that of the Nicliolson pavement. The final trouble, however, is their becoming polished and slippery, and hence they should not be laid in streets where they are subject to constant use. Iron Block Pavements. Several attempts have been made, with more or less success, to cast iron in blocks suitable for pave- ments. The chief objection is the cost of iron ; but if properly laid, there can be no doubt of its being cheaper in the end than most other pavements. It has failed here on account of its inadequate and de- fective foundation, and on account of the principle employed of keying. The rings pressing on the sand foundation gave too little bearing surface, and any weight tended greatly to displace ol* overturn the block, which occurring, all the neighboring ones key- ing into it were released, and unless quickly repaired, the ruin of the whole pavement soon followed. It has stood much better in Boston, and for the simple reason of its being better laid It has stood there admirably, and shows no material signs of surface wear after ten or twelve years of constant use. It can be cast in such form as to give the best foothold for horses drawing heavy loads. It can be kept per- fectly even and made smooth as the Nicholson pave- ment, and by its extreme hardness will give much less resistance to wheels. Being of uniform quality, all parts will wear equally, and as perfect a face will SiLICmCATION OF WOOD. 155 always be presented as when new. Its smoothness tends greatly to lessen the noise, as this nuisance is caused principally by the boxes of the wheels striking against the collars on the axle, and of course increases with roughness of pavement surface. Iron, further- more, loses but little from oxydation. It can be kept as clean as the Nicholson pavement, with the advan- tage of non-absorption. It has one great advantage, in being made so as to be easily and readily removed and replaced, the blocks formed from the same pattern being exact counterparts. The Fiske Concrete Pavement. This pavement is composed of seventy per cent, in bulk of broken stone, coal or gravel, clean coal or iron cinders, not over three inches in any dimensions. These are passed over a screen with meshes one quar- ter inch square. The coarser portion is then coated by mixing with tar, warm or cold, and then spread on the road-bed and heavily rolled until a depth of four inches is attained. The finer portion is then mixed with clean sharp sand, warmed, and then thoroughly mixed wdth tar, to which has been added rosin, carbojapanis or pitch. This is placed on the first layer of coarse material, and rolled until a depth of two inches is attained ; after which the surface is covered with an excess of clean sharp sand, and again rolled. Toe Nicholson Pavement. We now come to the subject of wooden pavements. The first general attempt to use wmoden blocks for 156 SILICIFICATION OF WOOD. pavements took place some thirty years ago, both in this country and Europe. They are generally made in the form of hexagonal prisms of hard wood, laid directly on sand or earth. Leading off in the list of wooden pavements adopted in this city is the Nicholson pavement. In laying this pavement, the street is first prepared by a sufficient covering of sand, which is brought to the proper crown with a straight edge made fur that purpose. This surface is then covered with common round inch boards, laid lengthwise with the line of the street. The ends of these boards rest on stringers of the same material laid from curb to curb. Both sides of these boards are covered with hot coal- tar. The blocks are of Southern pine, three inches wide and six inches deep, and are set on end in rows crosswise of the street. Before setting, the blocks are dipped to half their height in hot coal-tar. Between each row of blocks, and at their base, pickets one inch thick and three inches wide are nailed on edge. The opening thus formed between the rows is filled with clean screened gravel, rammed with a paver’s ram- mer, an iron blade made for that purpose, and then covered with hot coal-tar. The whole of the upper surface of the pavement, when laid, is covered with hot coal-tar, boiled to a consistency which, when cold, is to be tough, fibrous and not brittle, and then cov- ered with fine gravel and common sand. After the top gravel has become packed on the surface and in the grooves, the street is swept. SILICIFIOATION OF WOOD. 157 The M’Gonegal Pavement. This pavement, claimed to be an improvement on the Nicholson, to which it is similar, consists of a foundation of two inches of on which are placed wooden blocks six inches deep, two and three-quarter inches wide, and from four to sixteen inches in length. Holes of one and a half inches in diameter, and three and a half inches deep, are bored in each block, and then triangular grooves formed on each side of the blocks, so that when two blocks are placed together, there will be a square opening one and a quarter inch square to receive a wooden dowel or key. The wood used for blocks and keys is prepared for preservation by Pobbins’ process. In laying, the blocks and kej^s are dij)ped in hot coal-tar. The perforations in the blocks are filled with clean roofing sand. The pave- ment is finished by a coating three-quarters of an inch in thickness of coal-tar and fine sand. These are the specifications as we have described them ; but where this pavement has been laid in this city, a foundation of fiooring of tarred boards has been substituted for that of heton. The Stowe Pavement. In constructing this pavement, which is also wooden, and a cheap form of the Nicholson, the street is first filled with sand, loam or loose earth, free from stones, to within about six inches of the desired street grade, but smoothed ofi* so as to conform to the desired arch or crown of the street; then blocks ' of sound pine or spruce wood three inches in thick- 8 158 SILICIFICATION OF WOOH. nessj and six inches in length, are set on their ends in a tier across the street, these blocks being cut square at both ends. A tier of blocks made wedge-shape at their ends by beveling on one side is set across the street close against the first tier of square-ended blocks, which are set up as before, and so on alternate tiers of square and wedge-shaped blocks are placed, until a space of ten feet or more is covered, then the wedge- shaped blocks are driven down into the sand or earth wn'tli rammer and swage until the foundation is of the required compactness. The cells or spaces between the three-inch blocks are filled with clean coarse gravel, not exceeding three-fourths of an inch in diameter, thoroughly driven with rammer and swage, then the gravel saturated with hot coal-tar, and the whole surface covered with hot coal-tar, and lastly, the pave- ment covered with fine gravel or sand. The Ekown and Miller Patemeet. This pavement is also similar to the Nicholson, only that its blocks are not set vertically, but at an angle of forty-five degrees, and rest on sills of a prismatic form, which, in turn, rest on boards placed five feet apart, and parallel with the line of the street. The Pobbins’ Payement. This is another of the multifarious wooden pave- ments recently introduced in this city. It is very similar to the Nicholson, only the woqd used is first prepared by Pobbins’ patent wood preserving process. SlLtClB'lCATlON OE' WOOD. 159 The Stafford Pavement is only another imitation of the great original Nichol- son. The blocks are dressed to a imiform thicknessj grooved in the middle with a double dovetail, two and one-half by three-fourth inches, each side of the block beveled at one end, and running to an edge so as to form a groove on the upper surface. Seeley’s Concrete Pavement, now being put down in Eleventh-street, near IJniver^ sity Place, consists of sulphur, three parts; gas tar, twelve parts ; silica (pebbles) sixty parts, by weight. The pebbles are heated 230® Fahrenheit before being mixed with the melted sulphur and tar. General Directions for the Application of Silicate OF Soda to Wooden Pavements and Cements. The following method of application of the silicate is recommended by the author, and is reliable ; The planks and wooden blocks, intended as pave- ment, the si^e of the planks being from 10 to 12 feet in length and 1 inch in tliickness, and the blocks from 10 to 12 inches square, and in the first place ex- posed the iron boilers to a temperature of 300® F. for several hours, or kept for 4-6 hours in boiling water, containing 2 per cent, of soda ash, which possesses the property of dissolving the albumen and sap contained in the cells of the wood, and by the boiling the color- ing matter is extracted from the wood ; when taken 160 SlLIcmCATION OF WOOD. from the boilers, they are brought in drying chambers of high temperature, and then removed to vats con- taining crude carbolic acid and tar water, standing for 6-8° B., which will enter into the pores, left open by the previous process, and a large portion of the liquid will be absorbed ; from thence they are thrown into vats containing hot silicate of soda, standing 20^ B., and left therein for 4-6 hours ; they are then re- moved and dried either in air or hot chambers. When perfectly dry they are suitable for being put on a smooth ground, which may consist of a cement ofsili- cated hydraulic lime or cement. If strong cements, or lutes, where various other sub- stances along with the dry silicate and metallic oxides are to be employed, the soluble glass is not diluted, but employed from 30-35° B., sufficiently to make a plastic composition ; but where it is intended for mending or tilling cracks or holes, either in stoves or iron castings, discretion of the consistency of the mass must be used, as it may be more advantageous for the cement to dry slowly, so as to prevent too sudden a contraction. Bor painting or coating on stone, it is useful to apply the dilute by a syringe, and if necessary, repeat the operation 2-3 times after each drying. For pre- serving monuments, tombstones, marble columns, etc., the dilute silicate of soda may be used as a wash, with or without the addition of baryta, (the precipitated sulphate of baryta is always preferred, although ex- pensive,) lead, zinc or limewash, by means of a paint brush, and according to the condition of the stone as to porosity. If the chloride of calcium, chloride of iron, or dilute hydrofluoric acid are applied upon the SILICIFICATION OF WOOD. 161 surface of the stoue, cement or paint, they are thrown over the silicated surface uniformly, so as to cover every part of the material to be treated. In all cases it is understood that the silicate application is to be applied on new stone, for it will not adhere on old paint ; therefore, if it is to be used, it is indispensable that it be first removed by soap, caustic alkali, spirits of turpentine, or even acids, and when perfectly clean and dry, the operation of silicating may take place. In all cases wliere the substances are to be painted or undergo a silicification, it may be repeated 2-3 times, at each interval of at least 12 hours ; a weak hydro- fluoric acid may in all cases be used as a wash over the silicated stones ; 1,000 square feet of wall covering can be executed with 200 gallons of dilute silicate of either soda or potash. In diluting the silicate, it is well to employ 3 applications of various qualities, such as, for instance, the first coat may consist of 1 part of silica to 2 parts of water, and another of equal quan- tities of water, and the last coat the dilution to be 1 part of water. For Preservation of Walls. It is well known that brick absorbs its weight of moisture and requires much attention. Tlie external surfaces of the walls to be protected are first washed with a silicate of soda, which is applied again and again, until the bricks are saturated, and the silicate ceases to be absorbed. The strength of the solution is regulated by the character of tlie bricks upon which it is to be applied, a heavier mixture being used upon porous walls, and a lighter one on those of denser 162 SILICIFICATION OF WOOD. texture. After the silicate has become thorouo-hlv ab- O €/ sorbed, and none is visible upon the surface, a solution of chloride of calcium is applied, which, immediately combining with the silicate of soda, forms a perfectly insoluble compound, which completely tills up all the interstices in the brick or stone, without in any way altering its original appearance. By this operation the wall is rendered perfectly water-tight, and, as the pores of the bricks are thoroughly filled for a consider- able depth from the surface with the insoluble com- pound, which is entirely unafiected by atmospheric infiuences, no subsequent process is necessary. The Protection of Bail-Koad Sleepers, Cross- Ties, Frame Houses, Telegraph Poles, Timber, Staves, Shingles, Laths, Tanks, Tubs, Casks, Barrels, (Petroleum, Naphtha, Spirits Turpen- tine, Alcohol, Linseed Oil,) Cisterns, and Every Description of Wood, against Fire, Dry Pot AND Leakage. The seasoning or initiatory preparation of the lum- ber, so as to destroy the organic or nitrogenized mat- ters enclosed in all the cells of vegetable matters, are dissolved and washed out of it ; or, in other words, the removal of all the albumen, sap and coloring mat- ter, is effected by exposing from four to six hours to boiling water, containing about one per cent, of soda ash in solution. They are then withdrawn and dried in hot rooms, and then thrown into tanks containing the tar and carbolic acid water, and left for a few hours, then dried again and thrown into a hot solu- tion of silicate of soda, standing 20° B., in which they SILICTFICATION OF WOOD. 163 are left for ten or twelve hours. When removed from here a weak liinewash is applied with a brush or sponge, consisting of 10 lbs. slaked lime to 40 gallons of water, when likewise thej^ are removed to a dry or hot air ; after that a weak wash of chloride of calcium is thrown or brushed over them when nearly dry. Tlie process is then finished, and the articles so pre- pared will resist the elements as above stated. They increase in weight by this process about 6 perioent. After this treatment, they assume upon the first dry- ing a glazed appearance, and the pores are filled with insoluble silicas precipitated by the action of the tar licjuor upon the alkali of the silicate of soda. Barrels which have been treated may be rendered perfectly impervious, by filling up the chimes (the inside of those barrels having been treated with the silicate of soda and chloride of calcium) with a thin silicated cement applied on the interstices. 'No air nor any liquid will then have any effect ; the lightest liquid maj^ then be kept in those prepared barrels without escaping ; fiour, butter, lard, and many other perishable substances may be kept fur a length of time in barrels so prepared. Spirits of turpentine, linseed oil, alcohol, and other spirituous liquors, may safely be transported and kept for a length of time, without evaporation or loss in the contents of the barrels. Telegraph poles^ which are from twenty to thirty feet long, require a different treatment for their seasoning before they undergo the silicification. They are steeped first in the tar carbolic liquid, in holes dug in the ground with tanks built in the same, and left in there for several days ; then taken out, and undergoing the other process of silicate of soda, limewasli and chloride of calcium, as described, will render them proof against fire and dry rot. 164 CEMENTS. The Silica Cement, a Peeseryative to the Bottom OF Iron Ships. It is well known that iron ships have produced many disasters from rusting after long voyages ; the experiments tried for preventing the adherence of barnacles and the rusting have been very numerous. The author feels quite confident of success, by the pro- per application of a silica cement prepared by a hot solution of asphaltum and fine sand, manganese and liquid silicate of soda, and putting it on the bottom of the iron ships by means of a brush, and before becom- ing quite dry, to dust over the paint more powdered manganese. The Most Adhesive Lubricator. Black lead, 6 lbs., are mixed with 3 lbs. slaked lime; 8 lbs. sulphate of baryta are mixed with 7 lbs. of linseed oil ; the whole mass is well mixed togetlier to a uniform consistency, and the entire mass made more plastic with concentrated solution of silicate of soda. This cement may be used for numerous pur- poses, where hardness and adhesiveness are the desired objects,-*uniting at the same time steam and hot water. For locomotives, engines and machinery it is prepared from a mixture of silicate of soda liquid, at 25° B., added to fine plumbago, talc and asbestos in equal quantities, so as to retain the thin plastic condition, and capable of dropping it on the journals in very small portions. The Cheapest Whitewash, which is very durable for indoor and outdoor work, is prepared by the fol- CEMENTS. 1G5 lowing composition : To 1 lb. slaked lime and 1 lb. sulphate barjta, add 1 pint of silicate of soda and 1 pailful of hot water ; stir the materials well together, and use it at once. If the color is intended for a yeliow wash, add a quarter of a lb. chrome yellow ; if for a blue wash, use instead of the latter a quarter of a lb. of ultramarine, (worth six cents ;) and if the paint is intended to coat iron railing, stoves, steam- boat chimneys, and to obtain a brown or black fire- proof paint, add half a pound of manganite, an oxide of manganese, or the pyrolusite, which is the black or gray peroxide of manganese. The white wash or yellow wash just quoted is ex- tremely durable and cheap for wmoden fences along rail-road tracks, canal boats, farm houses, and other wooden structures. The Most Durable Aquarium Cement. The materials of a water-resisting composition are prepared by mixing finely powdered dry silicate of soda, powdered chalk, and fine sand in equal quan- tities, made plastic with the liquid silicate, and ap- plied at the joints, and worked over with fiuid chlo- ride of calcium, and when quite dry let some weak hydrofluoric acid pass over tlie cemented joints. This cement will be permanently impervious to water, and will not crack. The same composition is quite suita- ble for breweries, malt houses, linings for water-tanks, and cellars into which water flows. The author considers it advisable to show, also, the advantages of concrete, by quoting Tail’s system, ap- plied in Paris, and the description of the concrete 8 ^ 166 CEMENTS. bridge at London, and will state, that the addition of silicate of soda to the concrete will undoubtedly en- sure a great saving. The material consists of one part of Portland cement to eight parts of coarse gravel. The cement and gravel are tirst well mixed together in a dry state, and when this is done it is damped by means of a large watering pot, containing some hot silicate of soda, and again mixed by a pronged drag, such as is used for dragging dung out of a cart, until the entire heap has been wetted and mixed together. It is then put in iron or zinc pails and poured into the frame, where it is leveled by men stationed for the purpose. In order to save concrete, large lumps of stones or brickbats are put into the centre of the wall, and covered over and about with concrete. Frost does not affect the concrete after it has once set, which, with good cement, will be in about five or six -hours. JSTor do heavy rains appear to injure it in the slightest degree, though they may chance to fall ere the con- crete has hardened. The walls can be made straight and even as it is possible for walls to be, and the corners as sharp and neat as if the}^ had been formed of the most carefully dressed stone. The Soluble Glass as Manure for Grapevines. By putting the dry silicate of soda at the roots of grapevines, with or without the addition of phosphate of lime, has, by experiments, proved of immense benefit to the thriving of the vines to a proper thickness, and the grapes of uncommon size. CEMENTS. 167 The Soluble Glass a Substitute for Glue. It has proved quite useful in applying the liquid glass for glueing wood and paper together, instead of the common glue, and it is sold in the trade as mu- cilage, and applied on pasteboard instead of emery or corundum paper, used by cabinet-makers and other mechanics for polishing. As a paste for book-binders instead of glue, starch or dexterine, it has proved quite useful. Earthenware may be kept more durable by lining them with a weak solution. It is likewise used on leather, provided the same is not exposed to much ben din O’. The glazing or enameling of culinary vessels, made either for iron or stone ware, the soluble glass is use- fully applied in the following manner : The silicate solution of soda and potash is mixed with thick lime water; to 100 parts of the silicate add 1 part of lime water, made from 1 part caustic lime to 6 parts of water. The mixture is then evaporated to dryness and reduced to fine powder. By dipping first the objects to be glazed in the liquid silica, the powder is then sifted over them ; when dry, the operation is repeated again ; when dry, the coating becomes so hard that it cannot be rubbed off by the hands ; they are then treated like other ware by putting them in a furnace, requiring, however, not a very great heat. A similar process is to prepare a mass from 100 parts powdered quartz, 80 parts pure potash, 10 parts saltpetre, and 20 parts slaked lime, which mixture is made into a thin paste with the liquid silicate, and then burnt. This glazing is very durable, and resists 168 CEMENTS. both vegetable and mineral acids like common glass. It requires no great skill to execute the operation, and the expense to prepare such a glazing is but a trifle. Soluble Glass Application for Yarious Cements. Porcelain^ Glass and Metals are fastened together when broken, either by the liquid or gelatinous silicate b}^ the following method : Heat the object to be fastened together to that of boiling water, and apply the soluble glass on both sides of the fracture, press them together and leave them in a warm place for a fortnight, when they will be flt for use. Fluorspar finely ground, black oxide of manganese, oxide of iron, (crocus,) finely powdered soluble glass, and many more refractory substances are suitable articles to mix with the liquid silica for the various cements in use. A cement for fastening iron in stone, glass or wood is recommended, consisting in 1 part prepared chalk, 1 part marble dust, and made plastic with the liquid silica, or 1 part powdered soluble glass, 2 parts pow- dered fluorspar, made into a paste with the liquid silica, and this is for pasting labels on glass bottles. Caseine^ or metamorphosed milk, is also mixed with the liquid silica, and makes an excellent paste. Firejproof Cement is composed of the various oxides of iron, and formed into a paste with the liquid silica. The Athens Marlle Cement is composed of carbon- ate of lime, carbonate of magnesia and silica with oxide of iron, and made into a thin liquid and applied to tli^ stone, which, on drying, is permanently fastened CEMENTS. 169 to the surface, and protects it from smoke, dust and atmospheric agents. Common and fire brick acquire great strength if the silicate of soda has been employed in the manufacture, and become indestructible; they are then particularly fit for bakers’ ovens, wall and w^ell foundations and furnace beds. Glazed Pajper for apothecaries’ use, may likewise be prepared with the soluble glass. Metallic Cement is formed of a mixture of equal parts of oxide of zinc, peroxide of manganese and litharge, and made up with liquid silica and marble dust, and applied between the metals to be cemented. An Impeemeable Cement Eesisting Steam. It is prepared by mixing six parts finely powdered black lead, 3 parts slaked lime, and 8 parts of Plaster of Paris, made into consistency by the liquid silica. Zinc Cement^ for stopping cracks in metallic appa- ratus and other materials, is made by mixing equal weights of zinc white and finely powdered soluble glass with a solution of chloride of zinc of the den- sity of 126 ; it sets rapidly and resists the action of most agents. The simple mixture of oxide of zinc with a solution of the chloride of zinc, has also been recommended. The Gypsum and Clay Cement. This cement is very hard, and is prepared by an in- timate mixture with liquid silica, after the gypsum 170 CEMENTS. has been calcined, and it is preferred to lime cement, for the reason that by the action of fire, it becomes re- converted into lime, which, when the water from fire engines is brought to bear upon it, expands much, and forces out the walls to the destruction of the walls. Hard Cement. It consists in mixing 5 parts powdered clay, 2 parts iron filings, and 1 part of black oxide of manganese, and part borax, made into paste with liquid silica; wdien dry is very hard, and withstands water. Also, a mixture of manganese and zinc lohite witli Plaster of Paris forms a very hard cement, and has great ad- hesive capacity. Drain and gas pipes^ for conducting to sewers and houses, may be made as permanent as iron pipes by using a hard cement, consisting of hydraulic lime, clay and sand, mixed with fine powdered fluorspar and soluble glass, all made plastic by the liquid silica ; this mass, when dry and burnt, will resist a pressure of 600 pounds to the square inch, while iron pipes burst under a pressure of 40o pounds to the square inch. Cement for Closing Cracks in Stoves. It is prepared by mixing flnely pulverized iron, such as can be procured at the druggists, with liquid water glass, to a thick paste, and then coating the cracks with it. The hotter the Are, the more does the cement melt with its metallic ingredients, and the more completely will the crack become closed. CEMENTS. 171 Cement for a Cistern. Take 10 parts of Plaster of Paris. “ 2 “ Glauber Salts. “ 4 ‘‘ Clay. “ 4 ‘‘ Slaked Lime. Made in a plastic cement with the liquid silicate of soda, and, before it hardens, add liquid chloride of calcium. For sweetening the water in cisterns^ which is found to be hard, may be made soft by one gallon of silicate of soda in the cistern, and repeat the operation once a month. The hest iron cement is composed of calcined plas- ter and iron tilings, from each 10 parts, 4 parts oxide manganese, 2 parts slaked lime, made plastic with the liquid silicate of soda. A Strong Cement for Iron. To 4-5 parts clay, dry and powdered, 2 parts iron tilings, 1 part manganese, \ part salt, ^ part borax, in a paste made with soluble glass, or equal parts zinc white and manganese, made to a paste ; must be used immediately. The Peaslet Cement. The manufacturer of this cement has made himself celebrated and wealthy by his perambulations through- out the United States with a span of horses attached to a load of hay, so it is thought advisable to en- lighten the reader with its composition: White glue, dissolved in a large quantity of hot water, also 50 parts of isinglass, and 3 parts of gum 172 CEMENTS. arabic, and 3 parts of gum tragacanth, and to this solu- tion an alcoholic solution of white shellac; 1 part of the latter is then mixed with the watery solutign. To the whole are added 24 parts of white lead, and 12 parts of glycerine, and 200 parts of alcohol. It is immediately put in bottles and well corked. In other words : 200 parts white glue, parts lead, 12 parts glycerine, 200 parts alcohol, 50 parts isinglass, 3 parts gum arabic, 3 parts gum tragacanth, 1 part bleached shellac. Iron Cement for Water and Gas Pipes and Castings. It is obtained from sixty parts cast iron turnings, mixed with two parts of sal ammonia, one part fluor sulphur, and one part lime cement ; the whole made plastic by the liquid glass just before using it, to mend holes of whatever description in iron pipes or iron castings ; it becomes soon very hard, and every crevice is filled. Cement with Liquid Silica for all Purposes. A good cement, which will stand for many years without any paint. Good Portland cement is always recognised by its bright color of bluish tinge, but a common cement is of a dull slate color. For face work, two of gravel and one of cement is the best mixture ; with the finishing coat, half and half ; too much cement in the mixture makes it too rich, and is a common cause of cracks ; good cement should be- come hard the second day, so as not to be easily broken ; that which will crumble in the fingers on the second day must be condemned at once. CEMENTS. 173 - Cement intended for mouldings should be mixed with sharp sand, or a smooth finish cannot be ob- tained. Portland cement, gravel made plastic with the liquid silica, ought to be used only as the first coat, but not on the finishing coat ; if rain gets to it before being quite dry, it is very liable to perish. Stone Cement. Infusorial earth one, and litharge one, equal parts, fresh slaked lime one-half, and linseed oil, made into a homogeneous mass, assume the hardness of sand- stone, suitable to fasten iron in stone, such as foun- tains, vases, statuary, and in small quantity, may be used. Colored Cements. To a solution of silicate of soda of 1.29S, add, while stirring, first pulverized and previously washed lixivia- ted chalk, so as to form a thick mass, to which are added for coloring purposes the following substances : Por black, sulphuret of antimony. Gray, iron filings. Gray white, zinc dust. Bright green, carbonate of copper. Blue, orange and red, cobalt, vermilion and car- mine. This cement hardens in six to eight hours, and bears polishing like marble. Coating for Outside Walls. The following coating for rough brick walls is used by the United States Government for painting light- 174 : CEMENTS. houses, and it eifectually prevents moisture from strik- ing through : Take of fresh Hosendale cement three parts, and of clean, fine sand one part ; mix with fresh water thoroughly. This gives a gray or granite color, dark or light, according to the color of the ce- ment. If brick color is desired, add enough Venetian red to the mixture to produce the color. If a very light color is desired, lime may be used with the ce- ment and sand. Care must be taken to have all the ingredients well mixed together. In applying the wash, the wall must be wet with clean fresh water; then follow immediately with the cement wash. This prevents the bricks from absorbing the water from the wash too rapidly, and gives time for the cement to set. The wash must be well stirred during the application. The mixture is to be made as thick as can be applied conveniently with a whitewash brush. It is admirably suited for brick-work, fences, etc., but it cannot be used to advantage over paint or white- wash. Peeservation of Stones. Dr. Robert, in the Paris ‘‘ Les Mondes,” maintains that the use of the black oxide of copper, and its salts, will effectually prevent change in stone. He shows that the decay of granite, marble, limestones, sand- stones, and all natural building stones, is the combined effect of various causes, and that among these is a very minute lichen, the Lejpra antiquitalis^ which is one of the worst enemies of stone, and its action is to such an extent that, for instance, the beautiful marble sculptures of the well-known Parc de Ver- sailles will, unless proper measures be taken for stay- CEMENTS. 175 ing the process of decay, be unsightly and ugly masses of dirt, and quite irretrievably lost, as works of art, within the next 50 years. The author, taking as in- stances such buildings at Paris as the Bourbon Palace, the Palais du Corps Legislatif, the Mazarin Palace, {V Institute) the Mint, and others, points out that dust, spiders’ webs, and the action of rain, combined with the minute lichen above alluded to, hasten the decay of stone, especially of those parts where any sculpture or ornamental carving promotes the deposition of dirt and dust. Various places and instances are cited of the application of oxide of copper and its salts, which places are open to inspection ; and the length of time which has elapsed since such application, seems to warrant the conclusion that these compounds act as preservatives of stone. In reference to granite, the author states that this stone is also, according to the experience of Egyptian engineers, far more readily affected by a moist climate than one would be led to believe. The obeLsk of Luxur, brought from Upper Egypt to Paris, has become blanched and full of small cracks daring the 40 years it has stood on the Place de la Concorde ; although 40 centuries had not per- ceptibly affected it as long as it was in Egypt. Granite in a moist climate becomes the seat of a minute cryp- togamic plant, which greatly aids its destruction ; and it is, moreover, a well-known fact, that the disintegra- tion of this stone, which is composed of three separate minerals, (quartz, mica and felspar,) depends very greatly upon the thorough and intimate mixture, as well as the chemical composition, of these three in- gredients, each of which, in a separate state, more easily withstands the inffuence of the weather. 176 CEMENTS. Preseryation of Stone by Silica. The Yictoria stone seems to have endured severe tests and to promise well. The process by which it is made consists in mixing broken granite with hydraulic cement, and steeping the whole, when set, in a solution of silica. The granite used is the re- fuse of the quarries, and is broken up at the works. It is then mixed with Portland cement, in propor- tions of four of granite to one of cement, sufficient water being added to give it a pasty consistency. In this state it is placed in moulds, when it consolidates in about four days. When taken from the moulds it is placed for two days in a solution of silicate of soda, which completes the process. The silicate solution is prepared in a peculiar man- ner, and upon it the success of the operation depends. The silicate of soda has the property of hardening any kind of concrete in which lime is a component. This substance has been hitherto too costly for general use in artificial stone manufacture, and it becomes caustic by the absorption of its silica, so that it attacks the hands of the workmen. A Strong Metallic; Cement. It is intended to cement or unite metals together, and which hardens rapidlj^ ; may be made by stirring the finest Paris white in a solution of silicate of soda at B., so as to form a plastic mass, which may be colored by the oxide of manganese, or sulphuret of antimony, or iron filings or^iinc dust. Carbonate of copper gives a green color, oxide of chrome a dark green, red lead an orange, vermilion a scarlet, and CEMENTS. ITT carmine a violet color. After the application between the metals to be joined, the cement may be polished, and acquires a metallic lustre. It may also be em- ployed for the permanent repair of zinc ornaments. The Latest Chinese Waterproof Composition. Schoicao is a composition used in Pekin for cover- ing straw" baskets, which are intended to carry oil for long distances. Cardboards, when covered with it, become as hard as Avood. Most w^ooden buildings in the capital have a coating of it. The original w^as made of 3 parts of blood deprived of its febrine, 4 parts of lime and a little alum, and 'by adding 2 parts of liquid silicate of soda, will improve the mass very much. The most refractory cement is formed from silica^ asbestos^ flumbago and soajystone. These materials, mixed in certain proportions and made plastic by the liquid silica, form a most valuable cement for loco- motive journals and otlier lubricating purposes, for lining of steam boilers as well as coating, for tilling up airholes in iron castings. By the addition of per- oxide of manganese, it may be much improved, and serve as a permanent paint, which is fire and w^ater- proof. ARTIFICIAL STONE. The following notice of artificial stone has been taken from the Keport of the U. S. Commissioner to the Paris Exposition of 1867 : The agglomerated hetons have been extensively in* troduced in France in the construction of heavy pub* lie works, and in the erection of private dwellings, Nearly forty miles of the sewers of Paris have been constructed wholly of this material. All the founda* tions and basements of the palace of the Exposition, and other heavy structures in the Champ de Mars, those of the immense military barrack recently erected on the island of the city, the raihroad bridge of Ste. Colombo on the road from Lyons to Marseilles, a very large number of substructures for private houses, some houses entire, and innumerable foundations for the support of heavy machinery, have been constructed in the same way. The manufacture, as now generally practiced, was originated by Mr. Coignet, a French engineer, whose name is generally associated with the process. The following particulars in regard to the Coignet Mton are gathered from several sources, the most interesting being derived from a paper on the subject, published by Mr. A. Paul, civil engineer, of Paris. This substance is compounded of sand in large quan- tity, with lime in smaller, say in the proportion of five AUTmCIAL STOKE. 179 to one, more or less, and also, if rapid setting and nn- nsiial hardness are desired, with a quantity of cement, hardly more than one-quarter of the quantity of lime, the proportions being estimated by volume and not by weight. This mixture, in a condition nearly dry, and reduced to the form of a stiff paste, by being ground and worked up in mills constructed for the purpose, is introduced into the moulds designed to give it form, and compacted by repeated blows of a heavy rammer. The result is the production of a copy firm enough to allow the removal of the mould at once, by the separa- tion of its parts. The copy is perfect, since the yield- ing material, under the heavy impact of the ram, has been driven into all the minute-lines of the mould, and all the delicate traceries of the ornamental work. On exposure to the air the block rapidly hardens, and it has soon all the solidity of natural stone. The effect of the successive processes of grinding and ramming is singularly to increase the specific gravity of the product. The reduction of volume, when the bulk of the compacted mass is compared with that of the materials out of which it is composed, is nearly as two to one, (1.7 to one,) and the weight per cubic foot becomes about one hundred and forty pounds. Simul- taneously with the increase of weight, there occurs a very remarkable increase of strength ; the resistance of many specimens to compression amounting to more than two and a half tons to the square inch.^ An or- dinary mortar, made with precisely the same materials, * Specimens of very superior betons Lave even resisted crusbing pressures approaching to four tons per square inch of section. 180 ARTIFICIAL STONE. will be crushed by a pressure of probably less than five hundred pounds. The explanation of this greatly increased cohesive strength may perhaps be found in the following con- siderations : In mixing mortar an excess of water is always em- ployed, and this occupies much space, and by separat- ing the molecules of lime prevents their union, or acts unfavorably to what is called the setting of the mor- tar. If we suppose this setting, in the case of lime or cement, to be an actual, though perhaps confused, crystalization, whether of hydrate of lime, or of the silicate and aluminate of lime, mixed or combined, which constitute, in different proportions, hydraulic limes and cements, it follows that this crystalization will be so much the more energetic in measure as the water present in the mortar in excess during the pre- paration is more effectually eliminated, and that in the same proportion the union of the sand, lime and cement will be more intimate. It is the opinion of the engineer whose paper has been cited above, that the hardening of the compacted mass is not exclusively due to the physical properties of the lime and cement in their original condition, but is owing also, in a measure, to the conversion of these substances gradually into carbonates, and that this conversion goes on the more rapidly and becomes the more complete in proportion as the lime is more finely divided. Hydraulic lime should be used in this preparation. Fat lime may be employed, provided that a sufiicient proportion of cement be added to give it the hydraulic character. The lime should be well burned ; lumps ARTIFICIAL STONE. 181 which seem to be overburned or underburned must be rejected. It is slaked by sprinkling, and afterwards heaped up and allowed to lie some days in order that it may acquire its maximum of volume and become thoroughly disintegrated. It is then sifted through Ho. 35 wire gauze. In this powdered condition the slaked lime may be kept for lengths of time. It has been proved by the inventor, Mr. Coign et, that all kinds of lime, even the most common, after a while become as hard as the best. The only difference is in the promptness of the setting. In explanation of this fact, it is suggested that the ultimate hardness is probably due to the formation of the carbonate. The cements employed in the manufacture of these hetons are in general the heavy and slow setting cements. The sand preferred is river sand, mixed with particles of stone of from one to five millimetres in diameter. If the sand is too coarse, the resulting masses will be rough ; if too fine, it ssparates too much the molecules of the lime, retards the setting, and is prejudicial to the strength and durability of the resulting product. Pit sand answers very well ; but in order to produce a result equal to that obtained with river sand, it is necessary to increase the propor- tion of lime and cement. In mixing the materials, they are rudely measured, spread out on the ground, and turned with a shovel until the mass becomes homogeneous. They are then introduced into a tempering mill, and subjected to a very energetic grinding ; water being added sparingly from time to time, and only in sufficient quantity to give the m'ass cohesiveness, and bring it to the form of a paste as stiff as can be conveniently worked. The 9 182 ARTIFICIAL STONE. importance of this part of the operation is very great, since the rapidity of the setting and the degree of the ultimate hardness will depend upon the minute sub- division, which is the effect of the grinding in the mill of the particles of lime and cement. The tempering mill is one which has been con- structed specially for this purpose. It is of rolled iron, cylindrical in form, and has a vertical arbor in the centre, armed with knives set spirally around it. At the bottom, the cylinder is perforated with many holes, through which the material is expelled by the pressure of a cycloidal appendage attached to the arbor below the knives. The rapidity of the expulsion may be controlled by raising or depressing a cylindrical gate, resembling the gate of the Fourneyron turbine, the process being retarded as the number of holes un- covered is diminished. As the tempered heton is ex- pelled in the plastic condition at the bottom, additions are made to the quantity in the mill by introducing raw material at the top. The plastic heton thus obtained is thrown into the moulds in strata of from one to three inches thick, and beaten down and compacted by repeated blows of a heavy ram, weighing from fifteen to twenty pounds, applied all over the surface. The beating of a stratum having been completed, its surface is scratched and roughened by means of a rake, for the purpose of form- ing a secure bond with the stratum next to follow. Two kinds of moulds are employed, according as the object moulded is to remain permanently in the spot where it is formed, or is to be removed and built into a structure elsewhere. In the first case, the moulds are a species of coffer built up temporarily of wooden artificial stone. 183 walls united by horizontal cross-pieces, which are secured by bolts. To the interior of these coffer walls may be affixed the moulds necessary to produce archi- tectural forms, or the ornaments and decorations of staircases, portals, windows, &c., so that entire walls ma}^ be built in mass, with every appearance of being sculptured out of stone. For the preparation of por- table blocks, the moulds are more varied in construc- tion. They take the form of every description of ob- ject of which stone is the usual material, and serve to produce vases, urns, busts, statues, or simple cornices and friezes. The following proportions are given by Mr. Faul as those employed in the great monolithic structures of Paris, including the sewers and the substructures of the Exposition, viz. : five parts of sand, one of lime, and one-quarter of one part of cement in bulk. Such is the rapidity with which constructions in this ma- terial are carried on, that in six or eight hours after beginning work on a given length of sewer, it becomes safe and practicable to remove and advance the cen- tres ; and in four or five days after a section has been completed, it may safely be turned over for use. For arches with a pitch of one in ten, the propor- tions are, for the sand and lime the same as given above, but the quantity of cement is doubled. The groined arches of the ventilators of the Exposition, and of the substructures of the gallery of refreshments surrounding the Exposition palace, were constructed to this pitch, and thus a floor of vast dimensions was supported by isolated columns one foot in diameter and distant ten feet from each other in all directions. At the crown of the arches this floor was but a little 184 AKTIFIOIAL STONE. more than five and a half inches thick. The span of the basement arches of the city barrack is nearly twice as great, being 18.3 feet, and these arches are built to the same pitch. At the crown, in this case, the thick- ness of the material is nine inches. One month after the completion of one of these it bore a weight of forty- eight thousand kilograms upon twelve square metres of surface, or of forty-eight tons upon a surface of ten feet by twelve. A church has been constructed at Yesinet of this material entirely, the whole being a mass of hetcm without joints. The pit sand of the neighborhood was used, and the lime and cement were in the pro- portions first given above. But the pavements were made of a hUon richer in cement ; the quantity of this ingredient being made, for this part of the construc- tion, equal to that of lime. These pavements were very carefully rammed and smoothed with the trowel. In the lumber mill of Aubervilliers, the arches of the substructure, built of the Coignet heton^ are twenty- eight feet in span and fourteen inches thick at the crown. All the machinery of the saws is firmly fas- tened to the floors formed by these arches, by means of cramp-irons secured with lead, without having oc- casioned any injury to the structure during all the time the mills have been in operation. The most important of the benefits which are to result from the use of the agglomerated betms is pro- bably to be looked for in the superior stability and strength which they are destined to give to the foun- dations and basements of ordinary dwelling-houses. The usual mode of forming such constructions at pres- ent is to employ a certain amount of cut stone at inter- ARTIFICIAL STONE. 185 vals, and to till up the intervening spaces with nibble masonry. The entirely dissimilar character of these two kinds of masonry, with the great number of bonds or surfaces of junction between them, produces un- equal settling and the consequent cracking of the walls. Walls which are constructed of agglomerated heton are not liable to such accidents. Their whole mass forms but a single homogeneous block, stronger than even the rock on which it rests as a foundation. From the fact of their continuity, their weight is dis- tributed over the entire area of the foundation, and no settling can take place so unequally as to produce fracture. In a dwelling of five stories, in Miromesnil-street, Paris, constructed of a single mass of heton^ a staircase of the same material runs in helicoidal form from the basement to the highest fioor, moulded in the position where it stands. At the Paris Exposition of 1867, there were pre- sented specimens of the various applications of this important material, including a pavilion, as illustrative of its adaptedness to building in mass, lintels, cornices, friezes, paving slabs, troughs, garden benches and ta- bles, vases, monuments, urns, statues and nearly every other important object in which stone is commonly employed, whether for useful or for ornamental pur- poses. As scarcely ten years have passed since Mr. Coignet’s first experiments were made, and as it is only within the last two or three that the process has been perfected, or at least that its merits have been recognised, the heton agglomerS must be regarded as one of those new and useful things which the Expo- sition of 1867 was first to bring conspicuously before 186 ARTIFICIAL STONE. the world. At the Exposition of 1862, the efforts which, up to that time, had been made in this direc- tion, inspired in the jury in charge of the subject so little confidence, that the report of that body disposed of them all in the following summary manner : “ Many artificial stones which at first sight appear admirably adapted for this purpose [building] are found, when exposed to this unerring test, [actual experience of some years,] to be utterly wanting in durability. No artificial stone can, therefore, be considered durable as compared with natural stone until it has undergone the test of long experience;” a test which the jury were not disposed to think had as yet been satisfac- torily sustained by any such composition known to them. The crushing weight which the hHon of Mr. Coignet is capable of resisting has been stated at four hundred kilograms per square centimetre, or nearly fifty-four hundred pounds to the square inch. Its resistance to a force of tension is thirty to forty kilograms the square centimetre, or four hundred to five hundred and forty pounds per square inch. Experiments at Marseilles and at Cherbourg. The results, on the whole, are interesting and sug- gest the following conclusions : 1. Common lime can be substituted for hydraulic lime in beton-coignet, with an equally durable result, provided the blocks are allowed to harden for a few days on land previous to immersion. 2. Blocks of beton-coignet (sand and hydraulic lime) can be made in direct contact with the sea, provided ARTIFICIAL STONE. 187 they be protected by a crib during the time necessary for the taking, say 21 hours. Blocks thus made have proved as durable as those made on shore ; while under similar circumstances of immediate immersion in the sea, and 21 hours’ protection by a crib, blocks of ordi- nary concrete (sand, hydraulic lime, and stones) made with the same h^^draulic lime, would disappear in a short time. 3. Blocks of beton-coignet made on land are quite ready for immersion after drying and hardening for three or four days, while blocks of hydraulic concrete usually require from three to six months for drying and hardening. To supply the daily demand for these blocks of con- crete in the construction of a breakwater, large yards are necessary, which are usuall}^ at a distance from the breakwater. They must have space for 1,000 to 2,000 blocks in various stages of fabrication and dry- ing ; they require, also, a large establishment of ma- ehinery and railways ; a large capital is thus invested and the expense is heavy. In making beton-coignet less machinery and plant, less ground for drying, less preparation in advance are required, the time and capital involved are less, and the whole cost is consequently diminished. Mr. Coignet now proposes the construction of piers and breakwaters in the following manner : 1. Blocks of beton to be made on land, in length equal to the breadth of the pier and of corresponding size, weighing say 140 tons, to be lowered into the sea, and placed side by side, across the line of the pier, for foundation. 2. The wall to be constructed likewise of beton, in 188 ARTIFICIAL STONE. place, forming thus a single mass, binding the blocks below by the weight and solidity of the wall. For this he would use from five to seven parts of sand, one of lime, fat or slightly hydraulic, and one- fourth to one-half part of cement. But it is not probable that the government engineers consider the experience already gained sufficient to warrant them in recommending so great an outlay at present as this experiment involves. The materials of beton-coignet exist in abundance in all countries and in most localities, seldom requir- ing long and expensive transportation. Sand is easily excavated, lime is a simple prepara- tion, and both are materials of low cost ; most of the labor in making is performed by machinery, and little of the manual labor required need be skilled labor. Sand, lime, water, machinery, motive force, few tools and common labor, are the elements of structures made of beton ; and the beton itself is well adapted to numerous daily wants, in which solidity, durability and cheapness are preferable to beauty of materials, the evidence of which is shown in the ground and un- derground structures of the great palace of the Expo- sition, and in its increasing application to sewers, tanks, foundations, floors, walls, &g. The cost of beton varies with that of the lime and cement employed. In Paris, works in beton cost, in- cluding fabrication and construction, from $5 to $8 per cubic yard. Flagging, two inches thick, costs 56 cents per square yard. ARTIFICIAL STONE. 189 Kansome Artificial Stone. If Mr. Eansome has not found the philosopher’s stone, he has at least produced a stone wortliy a phi- losopher, and which promises to become the stone of the ages. For it appears to have elements of great durability, and it certainly possesses every other quali- ty desirable in building stone, whether for structure or ornament. Although five years are not five centu- ries, chemistry has analyzed even the tooth of time, and can produce, within the period of a comparatively brief experiment, results identical with those of ages of atmospheric corrosion and disintegration. Mr. Ean- some’s stone has been boiled, and roasted, and frozen, and pickled in acids, and fumigated with foul gases, with no more effect than if it had been a boulder of granite or a chip of the blarney stone. It has been boiled and then immediately placed on ice, so as to freeze whatever v/ater might have been absorbed, and it has been also roasted to redness, and then plunged in ice water, but without any sign of cracking or softening, superficially or otherwise. JSTor does its durability rest alone upon such evidence as this, for it is of the simplest chemical composition ; and chemis- try and geology alike testify to the durability, if not the indestructibility, of a stone which is nearly all silica, like Hint, and onyx, and agate, and jasper. It has no oxydizable constituent ; for silica, or silicic acid, is already oxydized, and thus it is unalterable in air ; and as the new stone is almost impermeable, it will suffer little, if any, injury from moisture or frost. “ And how marvellous, for its simplicity and beauty, is the process by which this stone is made ! Some 9 * 190 AETIFICIAL STONE. toiling mason or other, hewing in the quarry or in ithe builder’s yard, must have wished, before now, that stone, like iron, might be melted and run in moulds, even though his own occupation were thus at an end. Did he ever, when by the sea-shore or by a sand-pit, think of cementing indissolubly together the countless millions of grains into solid rock ? Mr. Ransome, no mason, however — unless he be, as he may be for any- thing we know, a member of the mystic brotherhood — did think of this. And he tried every cement he could lay his hands to, and did not succeed. The sand became little else than mortar by such sticking as he could effect. But he found out, at last — and we are speaking of a time more than twenty years ago — that the best sandstones were held together by silicate of lime. And so he set himself to work to produce this substance, indirectly, from flints, of which plenty could be found for the purpose. But the flints had to be liquefled flrst, and how could this be done ? Not by heat, nor would caustic soda touch them, so the chemist said. Flints might be boiled in a caustic solution for a week together, so long as the boiler was an open one, and lose very little by the operation. But by-and-by Frederick Ransome made one of the most unexpected discoveries in chemistry, viz., that when boiled in a caustic solution, under jpressure^ flints would melt almost like tallow before the Are. But we are not about to give the long history of the invention. With flint soup, or silicate of soda as a liquid, the question was what other liquid would, in mixing with it, turn both into an enduring solid ? What other liquid would turn both into silicate of lime, the substance he was seeking ? When he found ARTIFICIAL STONE. 191 that chloride of calcium (in solution) would, when mixed with silicate of soda, turn both into flint, or something very much like it, the road was clear, and the manufacture of stone from sand was as simple and as beautiful a process as the making of Bessemer steel from pig-iron by blowing air through it when in the melted state. “During the month of June, 1867, on the occasion of a visit of a party of about one hundred and eighty gentlemen, comprising heads of public offices and boards, chemists, geologists, engineers, architects and others, to the new works of the Patent Concrete Stone Company, at East Greenwich, Mr. Eansome showed and explained the whole process of making stone from sand, and exhibited some hundreds of the objects and ornaments, many of them of great beauty, already made to the order of architects and builders for various new buildings in England and abroad. “ The sand, a clean-grained, slightly brownish sort, just such as a dishonest grocer might select for increas- ing the gravity, specific or otherwise, of his sugar, comes from near Maidstone. There is no end to the quantity of it, and we believe it costs less than three shillings a ton in the Thames. There are flints enough for a hundred years to come brought up from the chalk pits at Charlton ; and the caustic soda and the chloride of calcium, the latter a waste product of the soda manufacture, are bought of the wholesale chem- ists. The silicate of soda is made from the flints and caustic soda as follows : The flints are heaped upon iron gratings within a series of cylindrical digesters, of the material, size and form of small steam-boilei*s. A solution of caustic soda is then added ; the digester 192 ABTIFICIAL STONE. is then closed steam-tight, and the contents are boiled by steam of seventy pounds taken from a neighboring boiler and led through the solution in a coil of iron pipes. The solution of caustic soda is prepared of a specific gravity of about 1.200. The fiints are dis- solved into ‘ soluble glass,’ and are drawn off in that state as a clear though imperfectly liquid substance, which is afterwards evaporated to a treacly consistency and color, and of a specific gravity of 1.700. The sand is completely dried, at the rate of two tons an hour, within a revolving cylinder, through which hot air is forced by a centrifugal fan. A small portion of finely ground carbonate of lime, say Kentish rag, or even chalk, is mixed with the sand, the more closely to fill the interstices; and each bushel of the mixture is then worked up in a loam mill along with a gallon of the silicate of soda. Thoroughly mixed with this substance, the sand has a sticky coherence, sufficient to enable it to be moulded to any form, and when well rammed, to retain its shape, if very care- fully handled. In this condition — moulded, of course, and any thing that can be done in founder’s loam may be done in this sand, sticky with silicate of soda — in this condition it is ready for the solution of chloride of calcium. The instant this is poured upon the moulded sand, induration commences. In a minute or so little lumps of sand, so slightly stuck together by the silicate of soda that they could hardly be kept from falling to pieces within the fingers, were solidi- fied into pebbles so hard that they might be thrown against a wall without breaking, and only a short further saturation was necessary to indurate them throughout. In other words, on the instant of con- ARTIFICIAL STONE. 193 tact, the silicate of soda and the chloride of calcium mutually decompose each other and reunite as silicate of lime and chloride of sodium, the former practically indestructible in air, the latter, common salt, perfectly deliquescent and removable by washing, although the stone, after the washing, is impermeable to water. Plaster of Paris does not set quicker than silicate of soda and chloride of calcium. ‘‘ The chloric solution is first ladled upon the moulded sand, and, the hardening going on, the ob- jects are afterwards immersed in the solution itself, wherein large pieces are left for several hours, the solu- tion being boiled in open tanks by steam led through it in pipes. This expels any air which may have lodged in the stone, and possibly heightens the energy of union with the silicate. “ After this the stone is placed, for a longer or shorter time, according to the size of the object, under a shower bath of cold water. This is not, by bathing, to covert it into Bath stone, although were the Bath stone a sandstone instead* of an oolitic formation, this name would do as well as any. The salt, or chloride of sodium, deposited throughout the interstices, is sought out and washed away, in brine, by the water, and were it not that a portion of undecomposed chloride of calcium is also washed out, this brine might be profitably evaporated for common salt. Now, this searching out of the salt by the water would appear to prove that the stone was perfectly permeable, but, by one of those paradoxes with which chemistry abounds, the stone, when once freed from salt, is almost impermeable. The action is one which, if it can be explained at all, can only be explained as one 194 : ARTIFICIAL STONE. of the phenomena of dialysis, as experimentally in- vestigated by Professor Graham. There is no doubt whatever that salt has been deposited everywhere throughout the stone, no doubt that it is afterwards completely washed out, and yet the stone as effectually resists the passage of water afterwards as if it were granite or marble. ‘‘ It is not necessary to describe the variety of ob- jects that may be made in the new stone. It is prac- tically a fictile manufacture, although not indurated by fire, and, unlike fictile goods, having no shrinkage or alteration of color in the making. Whatever the required size of the finished stone, it is moulded exactly to that size, with no allowance as in moulding fire-clay goods or in pattern making for castings in iron. The heaviest blocks for works of stability, and the most elaborately ornamental capitals, tracery or copies of statuary maybe made with almost equal facility. For any purpose for which natural stone has ever been used for construction or architectural ornament, piece ^ as tlie glass under operation is termed, near the pipe hose upon the edge of the marver. Again heated, it is now expanded by the blower into a large globe ; again presented to the fire, by the pe- culiar manipulations of the workman and the peculiar direction of the flame upon it, the front of the globe is flattened, the possibility of the globe collapsing during this operation being prevented by its rapid revolution around its axis. The piece now resembles somewhat in shape an enormous decanter, with a very flat bottom and a very short neck. The pipe is laid horizontally upon an iron rest, and a man ap- proaches, having in his hand the large rod, the ponty, tipped with a lump of molten glass ; pressing this lump upon an iron point so as to give it the form of a little cup, he fits it, wlien thus shaped, on to the bul- lion-point, to which it soon becomes flrmly attached ; the lump thus^formed is called the bull’s-eye or bullion of the developed plate. The incision of a piece of cold iron in the glass around the nose of the pipe, and a smart blow, soon detaches the pipe, leaving a corres- ponding hole in the flattened sphere at a point exactly opposite the attachment of the ponty ; the blowing pipe thus removed, and carrying with it a piece of glass, is allowed to lie idle a few minutes, till the glass adhering to it has cracked off; it is then warmed and carried back to the pot to repeat its course in a simi- lar operation. The open projecting end of the piece which w’as next the now detached pipe, is called the nose, and gives its name to the furnace or nose-hole. 240 ART OF GLASS MAKING. It is now the glass undergoes its last operation. A man stands in front of a huge circle of flame, termed the flashing flame, into which he tlirusts his piece rapidly, meanwhile revolving his ponty. The action of heat and centrifugal force combined is soon visible. The nose of the piece or hole caused by the removal of the blowing pipe enlarges, the parts around cannot resist the tendency, the opening grows larger and larger. For a moment is caught a glimpse of a circle with a double rim ; the next moment before the eyes of the astonished spectator is whirling a thin transpa- rent circular plate of glass, which but a few minutes before was lying in the glass pot. A flat circular disc, nearly sixty inches in diameter, or sometimes more, is produced, of almost uniform thickness, except at the point of attachment to the ponty, where there is a swelling called the bull’s-eye. Still whirling, the table, as it is now called, is carried off, laid flat upon a support called a whimsey, detached by shears or otherwise from the ponty, and lifted into the annealing kiln upon a fork. As the.jJ)ull’s-eye or centre lump which the ponty has left behind it keeps each, table from close contact with its neighbors, the air passes freely between them, and the annealing is completed with tolerable rapidity, varying from 24 to 48 hours, according to the number of tables in the kiln. From the kiln the tables are conveyed to the ware- house, having passed since their flrst exit from the pot through the hands of ten distinct workmen. The improvement in the details of the operation have produced a difterent result from that of former times. In the warehouse, the tables are laid upon a o^est or PLATE GLASS. 241 ciisliion, and are divided by tlie diamond of the split- ter into two unequal parts, the larger half containing the bnll’s-eye. The diameter of the table is measured on the rest, the usual size being now about 54 inches, and weighing thirteen pounds ; tables have been made as high as seventy inches, but the difficulty of manipu- lation, and the uncertainty of the result, render such sizes too costl}^ to be general. The splitter carefully examines each table before splitting, and turns it around until he has brought it into the position in which he may split it to the best advantage, announcing at the same time its quality. ly. Plate Glass . — This glass is formed by being castor founded upon a smooth table, while in a liquid state, and is totally independent of the process of blowing. It is not generally known that originally all plate glass was made by blowing, and not until 1773 was this glass cast in England, while in France the process has been used for one hundred years. The method formerly adopted was the same as the blown sheet glass ; the plates then produced were much smaller than can be executed by the casting process, which sometimes exceed ten feet in length, and about half an inch thick. Plates have been cast as much as fourteen feet long by eight to ten in width. The principal consumption of plate glass is for mirrors. In composition this plate glass is similar to cro'wn and sheet glass, the only essential bases being lime and soda ; the plate glass has the soda in excess, for the reason that it imparts a higher degree of fluidity, and because the impurities which it contains are more readily dissipated by the heat, so that the use of soda, 242 ART OF GLASS MAKING. though objectionable as tending to color the glass, fa- cilitates both the lining and casting. Plate glass consists bj analysis of — Silica, 75.9 Alumina, 2.8 Lime, 3.8 Soda, 17.5 It differs considerably from window glass in the proportions ; it is, therefore, more fusible, more readily altered, and less hard than window glass, and it is also less brittle, and less liable to be devitrilied. The French plate glass consists of — Pure sand, 100 lbs. Sal soda. 35 u Lime, 5 a Broken glass. 100 a Decoloring matter. 1 u Another French formula is : Sand, 100 lbs. Sal soda, 60 u Carbonate of lime. 13 ii Broken glass. 100 (( Peroxide manganese, 1 u Puly. smalt. i a The English formula is : The best washed sand and dried, 720 parts. Alkaline salt of 40 p. c , soda. 450 u Slaked and sifted lime. 80 (( Flitre, 25 (( Broken glass, 425 u PLATE GLASS. 243 This whole mixture of one pot of metal yields one thousand and two hundred pounds of glass. The main object of getting a fine metal is by giving the most perfect transparency to mirrors, and to destroy the slightest traces of coloration ; not alone must the metal or melted glass be thoroughly fused, but the original materials must be selected with great care. The sand must be very white and tine ; flint and quartz reduced to tine powder will suit well ; the soda per- fectly pure, so as to avoid the green tint which soda is apt to impart. The melting and lining is performed in two sizes of pots ; the larger is for melting the vitreous mixture and for keeping it long in a state of fusion ; the smaller for receiving a portion of the glass to be lined and cast, called cuvette or cistern. Furnaces for casting plate glass are constructed to hold six pots and twelve cuvettes, eight small and four large ones ; the small ones have the form of a perfect square, the large ones of an oblong rectangle. The ingredients for plate glass are fritted before melting, and then put in the pots in three successive charges ; the material is left sixteen hours, and during the melting of the mixture in the pots, the cuvettes are placed empty in the furnace, but as soon as the whole charge is in a state of fusion, the cuvettes are removed by means of tongs and cleansed from all impurities by a scraper, and are placed in the furnace, and after a few minutes heating, the ladling or trans- ferring operation commences. The surface of the metal in the pots is skimmed, and the liquid glass is transferred into the adjacent cuvette with a copper ladle, care being taken not to disturb any grains of 244 ART OF GLASS MAKING. sand or lumps that may have settled down on the bottom of the pot. The ladling is performed by two men ; each draws out the glass three times, and then plunges his ladle into cold water. The furnace is then shut, and the cuvettes are left to theipselves for the glass to fuse, or the bubble sproduced in the mass by the process of ladling or trejetage may be disen- gaged, and the excess of soda entirely volatilized. The melting lasts sixteen hours, and the fining also as long, and extends from 24 to 48 hours, or until all the bubbles are dispersed, and until specimens of the glass exhibit in every respect a fit state for casting. The casting process is as follows : While the glass is acquiring the requisite con- sistence, the annealing furnaces and the slabs or metal plate upon which is to be received the liquid glass, must be heated. The casting slab is now made of iron, and as large as to weigh 50,000 pounds, and cost 100,000 fcs., and is from 10 to 20 feel; in length, and the same in breadth, and from 6 to 7 inches thick, and rests on a strong wooden frame, movable on castors, or a rail-road, and is wheeled from one annealing furnace to the other. The height of the slab is made exactly on a level with the fioor of the arch of the annealing furnace ; its upper surface is fiat and pol- ished, to mould the lower surface of the mirror, and before the casting it is heated by hot coals spread over it, and then wiped perfectly clean. The annealing ovens being heated to a brown red, the casting slab brought to a suitable temperature, and the metal or melted mass thickened to the requi- site point for flowing readily and equably, the aperture PLATE GLASS, 245 into tlie cuvettes, . which are to be taken oat, is then opened, and two workmen introduce tongs into the farnace, and grasp the cuvette by the groove, while a third slides a large pincer under it. When that iu- struinent is pushed well under the bottom of the cu- vette, the workman draws it towards him, aided by the others with their tongs, which are supported on rollers ; in this manner the cuvette is drawn to the month of the opening, where it is raised by a crane, j)laced upon a truck or low carriage, and removed to the casting table ; the melted glass being §kimmed, the cuvette is then drawn up to a sufficient height by a tackle, and suspended above the upper end of the casting table, where it is tilted over by means of the tongs, and the metal is poured out on the table. The appearance presented by the molten sheet is now ex- ceedingly splendid ; the glass is prevented from run- ning over the sides by ribs or rims of copper, which are exactly equal in height to the intended thickness of the plate of glass, and when the cuvette has been emptied of its contents, a massive hollow copper c}din- der, three feet in diameter, and resting on each end on the side ribs, is set in motion. This cylinder, which weighs several hundred ^veight, is moved by means of the handles, wdiich form a prolongation of the axis, and spreads the glass out into a sheet of uniform breadth and thickness. To prevent any impurity from contaminating the glass, a workman drawls the w’asher covered with cloth immediately in front of the advancing sheet of fluid glass, the excess of glass pours over the front edge of the slab into a trough filled w'ith w^ater, and finally the roller passes off, and is re- ceived in the grooves. 2i6 ART OF GLASS MAKING. A beautiful plaj of brilliant colors, comprising every tint imaginable, is exhibited by the glass immediately after the roller has passed over it, probably caused by a temporary oxydation of the surface. While the in- troduction of the plate into the annealing furnace is being proceeded with, other workmen are engaged in taking from the fining furnace another cuvette, which arrives at the casting table at the moment when the preceding plate has just been introduced into the an- nealing oven. After filling the oven, all the openings are carefully stopped up with iron plates and clay mixed with sand. At the end of twenty hours some of the pieces of iron are taken away ; an hour or two afterwards more are removed ; as the oven cools, more and more are taken away, and at last the whole of the clay and plates of iron which stopped the aper- tures are removed. When the hand can be placed on the glass plates without feeling much heat, they may be taken out of the oven. The plates, after being withdrawn from the anneal- ing oven, have to undergo the operation of squaring^ grinding polishing j as taken from the oven, they are about half an inch thick, and present an irregular mottled appearance, roughened on the lower surface by the sand on which they have rested, and smoother, but not flat on the upper surface. The first process is that of squaring, or cutting them into their useful dimensions, and the workmen endeavor, notwithstand- ing the imperfect transparency of the glass, ‘to select those which appear to be free from defects, while such as show imperfections that cannot be removed by grinding, are picked out to be cut into smaller plates. PLATE GLASS. 24:7 The squaring is performed by passing a rougli dia- mond along the surface of the glass, guided by a square rule; the diamond cuts to a certain depth into the substance, when, by gently striking the glass with a hammer underneath the part which is cut, the piece comes away, and the roughness of the edge then left is removed by pincers. The plates having been squared, undergo then the process of grinding and polishing. Two plates are employed, one of larger dimensions, and one three or four times smaller, which are made to rub against each other, which is done by machinery ; the lower and longer plate is imbedded in Plaster of Paris in a perfectly horizontal position upon a table about two feet high, termed the grinding henohj the smaller plate is cemented upon the lower face of a swing table, made heavy by weights, and caused to traverse over the lower plate in such a way -that by a combination of a rotary and oscillating motion, the relative position of the two plates is constantly changed. In adjusting the plates, a rough or rolled surface of the one is opposed to the comparatively smooth or casting plate surface of the other, and the material employed to grind the surfaces is 'thrown upon the lower plate from time to time ; ground flint of different sizes is used for this purpose ; the ma- chinery is set in motion by a steam engine, and the process is continued until the ground plates exhibit a perfectly horizontal and even, though still unpolished surface. When one side of the plate has been suffi- ciently ground, it is loosened from the frame and turned over, so as to present the other surface to be ground in the same manner. Some degree of pressure is employed, by loading the upper plate with weights, 248 ART OF GLASS MAKING. as the grinding of each side approaches to completion. The process is now performed in less than three days. The plates require now another polish, which is done by grinding them with emery powder of increasing degrees of fineness ; after the application of the last or finest emery, the plate has become quite smooth and partly polished. The glass, although now per- fectly even, appears opaque and deadened on the sur- face, and still requires the final polishing. To effect this, a piece of wood is covered with numerous folds of woollen cloth, so as to form an elastic cushion, which is fitted with a handle ; the plate is imbedded in Plaster of Paris, as already stated, and the cushion being wetted, is covered with a fine earthy matter- consisting of crocus martis^ and is moved backwards and forwards on the surface of the plate with con- siderable pressure. By the grinding and polishing, the plates are reduced as much as one-third, and if any radical defects exist in the glass, these are only heightened by the polishing; those which are still found defective after tlie polishing, are cut up into smaller plates and polished again, while the perfect ones, when destined for mirrors, are subjected to a final process, wdiich is the silvering of mirrors, which is done by a compound of tinfoil and mercury. The operation is commenced by spreading a sheet of tinfoil, which must be of somewhat larger dimensions than the plate to be covered, upon a fiat stone or slate slab, termed the silvering table, and brushing mercury over it. When the surface of the tinfoil is uniformly covered, more mercury is added, till it covers the me- tallic sheet to the depth of one-sixth or one-quarter of an inch. This process is also a tedious one, and very PLATE GLASS. 249 dangerous for the workmen, and a new process lias latterly been substituted, by employing a silvering fluids obtained by mixing ammonia with nitrate of silver, and adding to it an alcoholic solution of some essential oil, like oil of cloves, cassia, &c., with a cer- tain portion of grape sugar ; this fluid has the property of depositing bright metallic silver, on the addition of the reducing liquid, consisting of the alcoholic solution of one part oil to three parts alcohol, and two parts grape sugar. Another reducing liquid is composed of 2 parts of nitrate of silver. 3 water. 1 “ ammonia. To this mixture is added one-fourth part of grape sugar, dissolved in weak spirit. For coating the inte- rior of glass balls, &c., gun cotton, dissolved in caustic potassa, with the aid of heat, adding to the brown so- lution a few drops of nitrate of silver and the ammo- nia, until the precipitated oxide of silver is re-dissolved ; this mixture is introduced into the glass ball or other vessel to be loricated, and heated in a w^ater bath, when, after a certain time, the mixture becomes black- ish brown, froths up and deposits all the silver upon the glass, forming a mirror which is said to reflect the light wdth surpassing brilliancy. The latest method, however, is used by adding a certain quantity of Eo- chelle salt, in solution, to the ammoniated silver of the above proportions, without the aid of grape sugar or oil of cloves. 250 ART OF GLASS MAKING. Petit jean’s Method of Silvering Glass. For one hundred superficial feet of plate glass, a mirror was completed in forty hours, while the opera- tion usually occupied ten days. Prepare two argentiferous solutions ; the first has 180 parts of nitrate of silver, which, treated with 62 parts of liquid ammonia of 870° spec, gravity, and 500 parts distilled water, the whole is then filtered^; this solution is afterwards diluted with sixteen times its volume of distilled water, to which is added drop by drop seven parts of tartaric acid, (Kochelle salt has been employed in this country and found preferable,) previously dissolved in thirty parts of water ; this liquid is marked No. 1 solution. The second solution is prepared precisely the same, only containing double the quantity of tartaric acid or Eochelle salt. The plate glass being cleaned with putty powder mixed with water, and spread over the entire surface with a ball of chamois leather, or a soft linen cloth, and leaving it to dry for a few minutes, and then rub- bing it oflF with another piece of chamois, the glass is placed on a rack, and an India rubber roller, moistened with distilled water, passed over it, to remove any particles of rust that may adhere to it. After this, it is laid upon a metallic table, covered with a wax or varnished cloth, and heated to about 120°. The plate being in a perfectly horizontal position, its sur- face is covered with No. 1 solution ; the deposition of silver commences in about ten minutes, and is com- pleted in fifteen minutes afterwards. The glass is then tilted up, so as to allow the liquor to run oflF, and FLINT GLASS. 251 rinsed with water more than lukewarm, to carry away the non-adherent powder. It is then restored to its horizontal position, and covered with No. 2 solution. In a quarter of an hour the deposit is completed. It is now washed as before and dried, after which it only remains to polish and burnish the film of silver de- posited, in order to make it perfectly smooth, and give closeness to the grain. In the last Paris Exhibition, the finest specimens of plate glass were exhibited ; one plate measured twenty feet by twelve feet ; one silvered mirror of nearly the same size ; the glass for them, and several other plates, was melted in a single pot, capable of holding a ton of the fused metal. The tin foil used for silvering weighs two pounds for every square meter. A large mammoth plate glass w^as lately imported from France, which measured twenty feet long and sixteen feet eight inches wide ; it is not intended as a mirror or window, but to represent, under a strong liglit, a frozen lake in a theatrical scene. Y. Flint Glass . — This is generally termed crystal glass, on account of its resemblance to rock crystal, the natural mineral ; it is chiefly manufactured into articles of domestic use and ornament, such as tum- blers, decanters, wine-glasses, vases, drops for chan- deliers, &c. In consequence of its great transparency and high refractive power, it is also formed into lenses for optical instruments. It is also called flint glass, on account of the employment of the flint, which is found in the chalk, as the source of the silica; for the sands are not only more free from iron, but less ex- pensive in the preparation than flints, when washed and calcined. The flint glass, properly speaking, is a 252 ART OF GLASS MAKING. lead or metal glassjin distinction from the other varie- ties of glass, and is distinguished from crown and plate glass by the use of potassa, instead of soda, in the manufacture. The term crystal, or flint glass, is now known to denote the double silicate of potassa and lead. It is well understood that the colorless crystal, or lead glass of the present day, or, in other words, a crystal pos- sessing that quality, which constitutes its chief beauty and value, is entirely of a modern invention. The analysis of the flint glass gives — Silica, 56.0 Lime, 2.6 Oxide of lead, 32.5 Potassa, 8.9 100.0 Many metallic oxides are capable of combining with silicic acid, and thus furnishing silicates which readily mix wnth alkaline silicates, but almost all these are colored. Till lately, the protoxide of lead and the oxide of bismuth were regarded as the only oxides capable of yielding silicates with little color, and con- sequently colorless glasses, by their mixture with the silicate of potassa in a proper proportion ; but a glass of zinc, which had a very pleasing and white appear- ance, and was specially suited for achromatic purposes, has been shown to have the remarkable property of being of greater specific gravity, and much more pure and pellucid than lead glass. Well prepared crystal or flint glass is alnqost with- out color, is more transparent, more brilliant, and FLINT GLASS. 253 heavier than plate or window-glass. It excels the fine Bohemian crown glass in refractive power and easy fusibility, although the latter is harder and more completely colorless. Flint glass of not less than the usual density of 3.200, well polished, is considered the nearest approach to the diamond ; it owes its bril- liancy and high density to the silicate of lead ; but as the latter is in itself yellow, it communicates a yellow tint to the crystal, when it preponderates over the alkaline silicate beyond a certain limit. It is a common mistake to suppose that great den- sity or weight is an advantage in crystal for articles of common use ; it is, on the contrary, a real inconveni- ence, and in the most favorable view, can only be con- sidered as a ready means of showing that the crystal or fiint glass contains enough of silicate of lead to im- part to it all the other qualities, which give it its pe- culiar value, and renders it preferable to other glasses for certain purposes. As lead affords the only me- tallic oxide which is usually employed in the manu- facture of fiint glass, so potassa is the only alkali which can be successfully associated with that ingredient to yield a colorless glass. The silicate of soda always communicates a blue or green tinge, which would be- come more perceptible and disagreeable in the thick articles usually manufactured of crystal. Crystal ves- sels are generally intended to receive mouldings, or cut ornaments, and do not admit of being made thin in the sides. The annealing would also become difii- cult in vessels of considerable size, without a propor- tionate thickness. Crystal is so fusible, that it is not easy to prevent such articles from sinking in or col- lapsing during the annealing. Tliis kind is, therefore, 12 254 ART OF GLASS MAKING. exclusively confined to the manufacture of thick arti- cles, and hence it is only the colorless silicates that can be used, namely, those of lead or zinc, and potassa. A good common flint glass is the following two for- mulas, the one with coal, and the other with wood as fuel : Sand, washed and calcined, COAL. 100 WOOD. 100 Red lead. 70 45 Purified potassa. 30 35 Cullet, 100 100 Saltpetre or arsenic, 2 2 Oxide manganese. 3 3 A highly pellucid and transparent flint glass is ob- tained of— Carbonate of potassa, one hundred weight. Red lead or litharge, two “ “ Sand, washed and burnt, three “ Saltpetre, from 14 to 28 pounds. Oxide manganese, from 4 to 12 ounces. Cullet at discretion. The best French formula is— Pure sand, 300 parts. Red lead, 215 ‘‘ Purified carb. potassa, 110 “ Nitrate of potassa, 10 “ Borax, 12 The lowest proportion of red lead that can be used, is in the following formula: FLINT GLASS. 255 Sand, Ked lead, Garb, potassa. Gullet, Arsenious acid. Oxide manganese. 300 parts. 180 ‘‘ 120 300 ‘‘ 45 60 The utmost attention must be paid to have the ma» terials in a perfect state of purity ; the sand should be very white, and free from coloring oxides of iron and manganese ; it ought to be washed with diluted hydro- chloric acid, and undergo eight washings of water, and afterwards pass through a heated coil called a calker, so that it is perfectly dry. The carbonate of potassa requires likewise a thorough purification, by dissolv- ing it in water, decanting the clear solution, and evaporating to dryness. The red oxide of lead must be made from pure metallic lead, for the commercial is never perfectly pure, but contains copper, iron and other oxides in too large a quantity. The few ounces of manganese are employed to neutralize the greenish tint produced by the presence of iron or other impuri- ties. The fiint glass furnaces are generally round, and contain from eight to twelve pots. It is also advisable to have two furnaces, instead of one, both opening into the same flue, for the reason, while one of the furnaces is in full operation, the other may be undergoing repair ; or the working of one may be entirely suspended, wfithout injury to the other, during a dullness of trade. Each of the furnaces may be capable of holding eight pots. Their shape is distinguished from those employed for other descrip- tions of glass, by being covered with a hood-shaped 256 ART OF GLASS MAKING. top, the mouth of which fits the working holes of the furnace, so that the smoke and heat cannot escape in the same way as in the usual glass furnaces. In France open pots are used for fiint glass, and as fuel, dry beech or oak wood ; so little carbon is pro- duced from the smoke as not to afiect materially the metal, although the flames play upon its surface ; but when coal or coke is used, the fumes and smoke emitted would carbonize or deoxydize the lead, and precipitate it to the bottom in the original metallic state, if the pots were not covered ; besides that, the solid particles of soot would blacken the glass, by attaching themselves firmly to its surface. The melting pots usually hold about 1,800 weight each, and the batch or frit is introduced in them by means of shovels in quantities of four hundred weight at a time, allowing a sufficient interval between each filling for melting down the various charges, until the pot is entirely filled with fused glass. In about twelve to fifteen hours every pot in the furnace is fully charged with liquid metal ; air bubbles* and striae then abound, and are not expelled until thirty or forty hours more have elapsed, when the mass becomes ho- mogeneous. The best results depend upon an intense and continuous fusion, for too little caloric will fail to refine the metal. During the founding, the mouths are securely stoppered and clayed up ; the shorter the time of fusion and refining the better ; for this purpose the heat can scarcely be too great. If the glass does not get fine by the usual time al- lotted, but becomes cottled o|^gelatinous, it never will recover, however urged by subsequent fusion ; such FLINT GLASS. 257 glass must be ladled into water, and considered only as cullet, for a re-fusion with a proportion of new ma- terials. The moment the metal is fully fused and re- fined by continuous rapid fusion, the high temperature of the furnace should be reduced from its maximum heat to a working temperature, this period being con- sidered the crisis. The mechanical operations connected with common bottle glass, crown, sheet and plate glass, are uniform in their character ; the description of the making of one bottle, or of one table, sheet or plate glass, applies to all ; the infinite variety of shapes into which com- mon fiint glass or crystal is manufactured, would be very tedious to explain. That glass is either formed by simple blowing with the pipe, and then shaping by hand or by blowing in moulds, or by moulds alone, in which the glass is subjected to pressure. In each of these cases the form and appearance of the articles are mostly improved by grinding, cutting, &c. A tumbler, for instance, may be made by hand. The workman collects on the end of a pipe a small quantity of glass, which is now rounded on the marver, expanded by blowing, or somewhat elongated by swinging, when it assumes the pear form ; the pipe is then suspended vertically, and the glass is allowed to drop by its own weight upon the marver, which flat- tens it at the extremity, and being at the same time further blown, assumes a bottle form. The pipe, with a portion of the glass, is then detached, by touching the piece with a cold pucellas ; this contracts and slightly fractures the glass, which is subsequently cracked through the entire circumference by a smart blow of the same instrument. In the meantime the 258 AKT OF GLASS MAKING. ponty has been attached by adhesion to the flat end, and the other end is flrst expanded with the pucellas, and then sheared otf so as to make it perfectly even, and fit it for the flashing or finishing ; finally, it is knocked off from the ponty by a sharp blow, and taken to the annealing arch. Wine glasses are usually made in three pieces, but the process is the same as for tumblers. The moulds for flint glass are carefully constructed of brass or iron, and when of simple con- struction are somewhat wider at the upper end, so that the pieces may be easily removed, or are composed of more than one piece, when projecting parts are to be moulded. A common open and shut mould, as is used for apothecaries’ vials, as well as for common wine bottles, are formed by two halves, connected with a bottom hinge; the glass to be moulded is gathered on the pipe, rolled on the marver into a cylindrical form, and then pinched with the pucellas at the end attached to the pipe, to form the neck of the bottle ; the cylindrical mass, still adhering to the pipe, is then inserted into the mould lying on the ground, its two halves are shut, and the workman blows through the tube, which renders the mass of glass hollow, while it receives from the mould the external form required. The third method of manipulation with flint glass, is moulding by pressure, which consists in dropping the soft metal into a prepared die, and then pressing down the matrix or plunger upon it by means of a lever. The finishing process given to the finer articles manufactured of flint glass is the cutting and polish- ing^ or more properly grinding this operation is per- formed by discs of iron, sandstone or copper, revolving FLINT GLASS. 259 in a lathe, which is usually propelled by steam ; the edges of the discs, which are sharp, angular or rounded, according to the work to be performed, are supplied with sand and water dropping from a hopper for rough grinding, and with emery for fine grinding. A stone wheel with water is employed to smooth out the rough sand marks, and prepares the glass for the polishing, which is effected b}^ means of a willow- wood disc, first with a mixture of pumice and rotten stone, and finishing with a preparation of tin and lead or glass putty; all table glassware and hollow articles are thus cut. Chandelier drops are cut or ground with iron and stone wheels in the same manner, but are finished with a lead wheel, supplied with fine rotten stone and water. Small copper discs of the size of a half-penny and finely pulverized emery mixed with oil are used to execute the outline and ground of the glass engravers’ work, and for polishing, lead wheels and very finely pulverized emery are employed. Coarse patterns for hall lamps are engraved by the glass cutters’ smooth- ing wheels. For inscribing initials, coats of arms and minute designs, very small discs must be employed. The finest incisions are made with copper pencils, either pointed or ending in a button-like disc. The etching on glass is performed by hydrofiuoric acid, either in the gaseous or liquid state, and exerts a peculiar action on glass, which has been turned to account as a substitute for cutting or engraving designs. For etching on glass by means of hydrofluoric acid, the glass is cleaned and a melted varnish poured upon it, which is spread in a homogeneous coating; the varnish is formed of wax and turpentine, say one part 260 ART OF GLASS MAKING. of the latter to four parts of wax ; a burin is then passed over the varnish, following the lines of the figure and cutting through the varnish to the glass ; when the figure is traced, the glass is ready to be exposed to the action of the hydrofluoric acid, which, according to the strength, requires from five seconds to five minutes ; the varnish is then removed by melting it with heat, and the glass is then wiped off with a soft linen rag. A finer varnish is required for more delicate designs and shades, which is a fat copal varnish, blackened with lampblack, which must be quite fine, and sprinkled with oil of turpentine; the coatings laid on must be very thin, and each should be quite dry before putting on a new one. The glass is sufiiciently covered with varnish when the light can scarcely be seen to pass through it ; the design is then copied through, and the varnish is removed from the lines with the points of gravers, or simple needles, of dififerent sizes and forms. This portion of the glass enables one to perceive the most delicate lines. After having formed the figure, it must be corroded out with liquid hydrofluoric acid. By a preliminary experiment or a coin-strip of glass, the time will be easily ascertained, which is required to be used on the article when the design is to be executed. Hydroflu- oric acid, diluted with soft water, one part of the first to six parts of the latter, is unquestionably the best material for cleaning plate glass and any other glass which may be sooty, or have any flaws on tlie surface. Optical Glass . — The most serious difiSculty, which has to this day impeded the progress of improvement of optical instruments of the highest order, has been the imperfection of glass. It is one which is so far OPTICAL GLASS. 261 from betraying to ordinary observers the faults, which make it useless to the optician, when the specimens which seem most brilliant are not seldom those which are in this respect most faulty. Two kinds of glass, crown and flint glass, are combined in the construction of achromatic lenses. Crown glass is only composed of silex, potassa and lime, while in flint glass the oxide of lead is added. The unequal density of these two glasses prevents their forming, while in a state of fusion, amass of uniform character; the heavier of the two tends to sink to the bottom of the crucible, and the result is to produce a compound of very une- qually refracting power. Nearly flfty years ago the great English philosophers, Faraday, Herschel and Dollond, entered into experimental inquiry, for the purpose of devising means of overcoming such a great difliculty ; which, however, did not advance the prac- tical object in view, although the results of their in- vestigations were, in many respects, highly interesting. The largest telescopic objective of satisfactory per- formance did not exceed flve to six inches in diameter. At the Paris Exposition of 1867, the most brilliant dis- play of optical glasses was exhibited, which have quite satisfactorily proved the equal density and uniformity of refractory power. The process is made known to consist of uniting numerous small selected masses of glass of ascertained equality into one large mass by pressure, while in a plastic condition ; it resembles the process of the welding of iron, and the great problem is now fully solved. The same manufacturer exhibited several specimens of the silico-borate of lead, a glass of great speciflc gravity, and which he calls heavy glass^ its specific gravity varying from 4.20 to 5.44. 12 * 262 ART OF GLASS MAKmQ. great magnificent disc of flint glass of over twenty-eight inches was also exhibited. At the same Exposition a great variety of glass plates were exhibit- ed ; one of them, by actual measurement, was found to have the dimensions of nineteen feet and six inches by eleven feet. The exhibition of prisms was very excellent ; very large four inch right-angled prisms, and some rock crystal prisms, suitable for the study of the fluorescent rays beyond the violet ; also, hollow prisms for ex- periments on transparent fluids, were formed of plates of plain glass united without cement, being made water-tight by the perfection and polish of their surfaces. For illustrating the laws of refraction, were prisms with horizontal axes of variable angles for fluids. The best proportions for an optical glass are the following : For flint glass : Sand, 43.5 Bed lead, 43.5 Carbonate potassa, 10. Nitrate potassa, 3. 100. For crown glass : Sand, 60 Carbonate soda. 25 Carbonate lime. 14 Arsenic, 1 100 ZINO OPTICAL GLASS. 263 It will be observed, that optical flint glass is chiefly distinguished by the large proportion of lead which enters into its composition ; its density should not be lower than 3.6 at least. The essential point in the manufacture, however, consists in the constant stirring of the metal during the melting and fusing. The superiority of Guinaud’s plan is considered not to have been in the novelty of the materials or propor- tions, but in carefully agitating the liquid glass while at the highest point of fusion, then cooling down the entire contents of the pot in a mass, and when annealed and cool, separating unstriated portions by cleavage. Faraday’s heavy glass, which has proved so important in experiments connected with the polari- zation of light by magnetic action, is composed of the following ingredients : Protoxide of lead, 104 Silicate of lead, 24 Dry boracic acid. 25 This glass required but a red heat for fusion,' tliereby offering facilities for minute agitating opera- tions ; it was found, however, not to be durable, and not calculated for application to optical purposes or general use. Zinc Optical Glass . — The basis of this vitreous com- pound is the oxide of zinc, a certain quantity of borax or boracic acid being added to give tlie glassy charac- ter for whicli the boracic compounds, no less than the silica, are so eminently remarkable, combined with an easier fusibility ; it is suitable for the crown glass in achromatic telescopes, but not for the flint glass ; the 264 ART OF GLASS MAKING. low dispersive power of the zinc compound, points to the use of glass of zinc for this purpose. YI. Strass and Colored Glass . — The manufacture of glasses tinged, colored or stained by different processes, has become a business of great and growing import- ance. The taste for stained glass windows, which formed so distinguished a feature in the history of a former period, has revived, and is now displayed in the decoration not only of splendid palatial and ecclesiastical structures, but even of many private dwellings, steamers, &c. The skill of the Yenetians of a former day in producing colored vases and other ornamental articles of glass of every variety of hue, is equaled, if not surpassed, in modern times ; artificial gems or pastes, which are true glasses, are now formed, that emulate, if they do not eclipse in sparkling lustre and pure transparency, the rarest and most beautiful natural productions of the mineral kingdom. The basis of the color, or that with which the coloring matter is actually mixed, is a lead glass, and this, when real glass painting is the object, is applied either as a pigment, or in a melted state on common glass or some other finished article ; in other cases the colored lead glass is itself formed, cut or moulded into the finished article. When the latter is an artifi- cial gem or paste, a peculiar glass is employed termed strass y which it may be proper to describe now. This paste, having its name from the inventor, constitutes the only true glass not yet hinted at in this treatise, but forms the basis of artificial imitations of precious stones. Tor this purpose a glass is required, possess- ing the highest degree of purity and transparency, combined with the greatest possible lustre. These STEASS AND COLORED GLASS. 265 requirements are found in a composition analogous to that of flint glass, but containing a much larger pro- portion of oxide of lead and a little boracic acid. The three following mixtures are recommended : Ground rock crystal. ONE. 100 TWO. THREE. 100 Sand, — 100 — Pure red lead. 156 — 154 White lead. — 171 — Purifled caustic potassa, 54 32 56 Boracic acid. 7 9 6 Arsenious acid. 3 3 16 ^ The oxide of lead is in excess of all other glass, even optical flint glass. When strass is well prepared, it possesses as nearly as possible the high refractive power, and all the other properties of the diamond, except its hardness. When cut into shape without any coloring, it answers for imitating the diamond ; and when tinged by silicates with metallic bases, it fur- nishes imitations of all the colored stones. Its perfect purity and high lustre are the essential requisites,, and for this reason requires great care in the choice of the materials. A pottery furnace and Hessian crucibles are used for melting the material, which is to be kept in the Are for twenty-four hours; the more tranquil and prolonged the fusion, the greater hardness and beauty does the strass acquire. The coloring materials used for the imitation of gems, are the following : Yellow is produced either by charcoal, antimony, silver, or oxide of uranium ; a very superior yellow, 266 ART OR GLASS MAKING. by roasting the sulphide of antimony to the state of antimonious acid, or the white oxide of antimony, and melting it with from three to live per cent, of unde- composed sulphide of antimony. An orange yellow is obtained by glass of antimony, red lead, and a little oxide of iron ; in these cases the substances so pre- pared are mixed with the materials of the glass. When silver is employed, the process is quite differ- ent. In this case a mixture of powdered clay and chloride of silver is applied to the surface of the ready- made articles, and on reheating these in a muffle, the silver penetrates to a certain depth into the glass, even before the latter softens ; the article is then allowed to cool, and the coating which was applied is scraped off, when a yellow color of great purity and brilliancy appears on the glass ; very remarkable it is that this effect can only be produced on glass containing alu- mina, which shows that it is a chemical, and not me- chanical action. Oxide of uranium produces a beauti- ful delicate yellow of a slightly greenish hue. E-ed of different shades is communicated by oxide of iron, sub-oxide of copper, or different preparations of gold, mixed with other materials ; the oxide of iron is em- ployed, either as pure oxide, prepared by heating the nitrate, or in the state of red hematite or ochre ; it produces, if added to the glass mixture, a cheap and very common brownish red. The peculiar action of sub-oxide of copper was much employed by the artists of the fifteenth and sixteenth centuries, for producing the brilliant red colors of window panes ; and in later times the glass so colored was supposed to be indebted to gold for its beautiful rich hue. So intense is the STRASS.AKD COLORED GLASS. 26 T coloring power of this oxide, that even a very small quantity reddens the glass so much, as to render it opaque, and hence it is almost impossible to command any desired tint in applying it ; recourse is had, to ob- viate this difficulty, to the process of flashing^ or coat- ing with colored glass. The application of gold for producing a brilliant red color, which can be made to assume a scarlet, carmine, rose or ruby tint, has long been known, having been made by precipitating a solution of chloride of gold wdth a salt of the sesquioxide of tin, under the name of cassius jpurple y the simple addition of a solution of gold to a flux, without any oxide of tin, is, however, capable of producing rose and carmine colored glass. Blue is produced by oxide of cobalt, a pigment which is equally applicable to lead glass and to glass containing no lead. The coloring power of the oxide of cobalt is so intense, that pure white glass is made sensibly blue by the addition of one thousandth part of the oxide. Smalt and zaffre are but impure oxides of cobalt. Green is produced either by protoxide of iron, pro- toxide of copper, or oxide of chromium. The tint produced by the first has little brilliancy. The oxide of copper gives a beautiful emerald ; for this purpose the glass is mixed with the product obtained by heat- ing copper to redness with access of air, or with powdered verdigris, which is then decomposed in the fire and converted into oxide by oxydizing agents. Care must be taken to prevent the protoxide of iron from being converted into sesquioxide, and the oxide of copper from being reduced to sub-oxide. 268 AET OF GLASS MAKING. Artificial Gems . — The following is a formula for the production of artificial gems : Diamond . — Colorless strass without any addition. Toj)az . — White strass, 1000 Clear orange red glass of antimony, 40 Purple of cassius, 1 Also of strass, 1000 Oxide of tin, 10 Ruby . — This is the rarest and most highly priced of artificial stones ; the mixture for topaz often gives an opaque mass, translucid at the edges and presenting in its tliin plates a color red by transparency. One part of this opaque mass and eight parts of strass, melted in a Hessian crucible, when left 30 hours in the fire of a potter’s furnace, gi ve a fine yellowish crystal similar to strass. Remelted with the blow-pipe, this produces rubies of the first water. A ruby not so fine and of a different tint may be made by employing the following proportions : Colorless strass, 1000 Oxide of manganese, 25 Emerald . — It is very easy to imitate ; the mixture of oxide of copper with colorless strass gives the best results, and if oxide of cobalt is added, the green obtained presents blue reflections. The composition which gives the best imitation of natural emerald is as follows : Colorless strass, 1000 Pure oxide of copper, 8 Oxide of chromium, 0.2 By increasing the proportion of chromium or oxide ARTIFICIAL GEMS. 269 of copper, and adding oxide of iron to the mixture, one may vary the green shade, and imitate peridot or dark emerald. Sapphire . — To produce a fine oriental blue color, one must employ very white strass and very pure oxide of cobalt. The composition, put into a luted Hessian crucible, should remain 30 hours in the fire. The proportions are as follows : Colored strass, 1000 Oxide of cobalt, 15 Amethyst . — The color of this stone must be fine and velvety, to be of any value. The formula which succeeds best is the following : Colorless strass, 1000 Oxide of manganese, 8 Oxide of cobalt, 5 Purple of Cassius, 0.2 Aquamarine . — It is of pale emerald tint, but the most valuable kind is colorless like the diamond. It is obtained artificially : Colorless strass, 1000 Glass of antimony, T Oxide of cobalt, 0.4 Syrian Garnet or Carbuncle . — It has a lively color, and is much used for small jewels. The artificial garnet is a kind of dark ruby, and is made after the follow- ing formula : Colorless strass, 1000 Glass of antimony, 500 Purple of cassius, 4 Oxide of manganese, 4 270 AKT OF GLASS MAKING. In the manufacture of artificial stones, there are many precautions to be taken, and many points to be observed, which can only be acquired by experience. The materials must be finely pulverized. The mix- tures can only be well made by repeated sifting. To obtain masses well melted, without any strise or bub- bles, it is necessary to employ the purest substances, to use the best crucibles, to melt with a graduated heat in a furnace which is quite equal to its maximum temperature, to leave the metal in the furnace at least from 24 : to 30 hours, and to cool the crucibles very slowly, that their contents may undergo a kind of annealing. So/^ WAiU Enamel. — To 600 weight of batch add twenty-four pounds of arsenic and six pounds of anti- mony. Hard White Enamel. — To 600 weight of batch add 200 pounds of putty prepared from tin and lead. Blue Transparent Glass. — To 600 weight of batch add two pounds oxide of cobalt. Azure Blue . — To 600 weight of batcli add six pounds of oxide of copper. Ruhy Red. — To 600 weight of batch add four ounces of oxide of gold. Amethyst or Purple. — To 600 weight of batch add twenty pounds of oxide of manganese, (pure.) Common Orange. — To 600 weight of batch add twelve pounds of iron ore and four pounds of man- ganese. Emerald Green. — To 600 weight of batch add twelve pounds of copper scales and twelve pounds of iron ore. Gold Paper Color. — To 600 weight ofi batch add FLASHED GLASS. 271 three pounds of oxide of uranium. Under a batch is understood the mixture of materials, such as that for flint glass as noticed in previous pages. Flashing and Casing , — Heferring to the sub-oxide of copper, it was remarked that the coloring power was so intense, that even a very small quantity wmuld render the glass opaque, and that the process of flashing had to be resorted to, in order to overcome the difficulty. This process consists in coating a layer of colorless with one of colored glass, which can then be reduced by grinding to the proper tint. For this purpose the glass-blower collects the proper quantity of colorless glass on the end of his pipe, rolls it upon the marver, and then dips it for a moment into a pot of melted colored glass, and blows out the two together into a cylinder or globe, wdiich is flattened or flashed out in the usual manner, which is the way how panes for the glass painter are formed, which consist of two layers of glass, one colored the other colorless, and the former can be ground down to any required tint or degree of transparency. An ingenious application of this process is made to vessels of flint glass, which are colored on ^the outside in a similar manner, and colorless edges or facets are then produced by cutting through the outer layer of colored glass into the sub- stratum of colorless glass. . Flint glass is colored in a similar manner, by the process called casing, in the following manner : If any two or more glasses intended for casing have been mixed of the same specific gravit}^ to give them the capability of harmonizing, tliat is, of contracting and expanding equally, the blower has to gather a ball of solid glass intended for the interior layers in the usual 272 ART OF GLASS MAKING. manner, wliicli may be considered to be of white crystal glass ; about the same time his assistant pre- pares a casing of colored glass, knocking off the knob to open and shape it, somewhat like the bowl of a wine-glass, or the broad end of a large egg-shell ; this is set in a metal stand on the floor, merely to steady the case or shell, while the blower takes the lump of flint or white glass, and gently blows it into the co- lored ease or shell, to which it immediately adheres, and when submitted to a pot hole, it is found to weld perfectly. Yenetian Filagree work is produced in the follow- ing manner : Pieces of cane, or solid rods of glass of different colors, having been drawn out in the same manner as tubes, and whetted off to the required lengths, are arranged in the flutes or internal grooves of a cylindrical mould ; the blower then inserts a solid ball of transparent flint glass, and the whole is exposed to a welding heat till the canes adhere to the ball ; both are then withdrawn with it from the mould. The Venetian Ball is simply a number of pieces of waste filagree glass collected together without regular design. The Millefiore^ or star work of the Yenetians, is formed by placing lozenges of glass cut from the ends of colored filagree canes in the interval between two transparent canes. Glass Mosaic is produced by threads or small canes of variously colored opaque or transparent glass of uniform lengths, ranged vertically side by side in single threads or masses, so that the ends shall form grounds agreeably to some prefigured design. Yenetian Frosted Glass is obtained by immersing the GLASS PAINTING. 273 gathering of hot metal in cold water, quickly with- drawing it, reheating and expanding it by blowing before it becomes so hot as to melt, and weld together the numerous superficial cracks produced by the momentary immersion in cold water; these cracks onlj^ penetrate as far as the metal has been cooled by the water, and remains as depressions until the article is finished. Avanturin Glass is an easily fusible brown, or in thin layers, yellow glass, interspersed with spangles or numerous fine yellow laminse with a metallic lustre, which give it a peculiar shining appearance. The manufacture was long kept a secret by the Yenetians. It was commonly supposed that avanturin glass was produced by melting scales of metal or mica with the glass ; but when examined under the microscope, these scales appeared as regular three or six sided tables, perfectly crystaline in structure ; and it was ascertained that the spangles consisted of metallic copper crj^stal- ized in the form of fiat seo;ments of a regular octahe- dron. The following mixture, after fusing together for twelve hours, produce a good result : Pounded glass, 300 parts. Copper scales, 40 “ Iron scales, 80 “ The fused mass must be cooled slowly ; the glass obtained is somewhat deficient of lustre, but it con- tained copper diffused through the mass in octahedral crystals. Glass Painting , — Painting on glass is performed by means of a vitreous mixture termed tlie flux, com- 274 ART OF GLASS MAKING. bined with a pigment prepared from some metallic oxide ; the flux and oxide are simply that combination of ingredients which is necessary to produce a highly fusible colored glass of the required hue ; this mixture is reduced to a state of flne powder rubbed up in oil of turpentine, boiled oil, or sometimes simply with water, and laid upon the glass to be painted by means of a brush; the glass thus painted or stained with the intended design is then exposed to a heat sufticient to vitrify the mixture of color and flux, without melt- ing the glass ; in other words, the painting is said to be burnt in, the ingredients of which it is composed are converted into a colored glass or transparent picture, while the pane or other article on which it is laid is only sufficiently softened to cause the complete adherence of the colored glass to its surface. The fusing point of the pigment must be much lower than that of the glass to be painted ; it is even necessary that the former should vitrify at a tempera- ture at which the latter does not sensibly soften, for any considerable softening or yielding of the glass would distort the design ; hence the manifest inappli- cability of crystal on lead glass for painted articles, on account of its great fusibility. Common window or plate glass may be successfully used, and best of all, the hard Bohemian glass, which contains potassa for a base. The flux is usually composed of the following ingredients ; Quartz in powder, 100 parts. Oxide of lead, 125 “ Oxide of bismuth, 50 “ SPUN GLASS. 275 Bat if these oxides exert an injurious action on the colorinoj matter, and tend to change its shade, the sub“ joined composition is used : Carbonate of lime, free from iron, 12.5 “ To each of these mixtures or fluxes the proper co- loring matter is added, and the composition so formed is introduced into a crucible and melted into a colored glass; the latter is then reduced to a fine powder, mixed, as has been stated, with oil of turpentine, and used as a common pigment for painting on the less fusible glass. In this operation a cartoon, or drawing upon paper, is placed below the glass, and the colors are applied on the corresponding lines. In preparing painted sheets or panes of glass, brown or black out- lines are generally traced on the one side of the sheet, while tho colors are laid on the other side ; but in painting vessels or other articles, this is not the practice. Sjpun Glass . — The art of spinning glass consists in drawing it out into threads, when softened, by means of a wheel on which the thread is wound ; the drawn out end of a glass rod has only to be attached to a re- volving drum, while the rod, whence the thread pro- ceeds, is held in the glass-blower’s lamp, in order to obtain, in a few minutes, several yards of spun glass. Glass from Cryolite , — An opaque glass, or, as it has been called by the manufacturers, ‘‘ hot cast porcelain,” has been introduced a few years ago in this country Quartz in powder. Fused borax, Nitrate of potassa. 100 parts, 75 12.5 “ 276 ART OF GLASS MAKING. by a company who purchased the monopoly from the Danish Government for exporting the mineral cryolite from Greenland. This species of glass is composed of ten pounds crjmlite, twenty pounds white sand, and five pounds of oxide of zinc, which composition is well mixed and exposed in the furnace at the same high temperature as any other flint glass. We have seen a great variety of utensils cast in moulds of tiles, mantelpieces, statuary, mortars, evaporating dishes, pill tiles, funnels, ointment jars, and many other arti- cles, capable of being cast, blown, or moulded, whilst in a melted state, and at a mere trifling cost, and to all appearance have the advantages over many other wares now in use. Mortars have stood the pounding and trituration better than a wedgewood mortar, and the evaporating dishes resisted the heat of both the sand and water baths, and all at about half the cost of ordinary porcelain. Lamp shades, and other fine parlor ornaments, finished in the best manner, and slabs of six feet long and four feet wide, without a fault, the writer saw in the sample room of Ihe com- pany. This glass or porcelain bids fair to supersede the French porcelain for toughness, strength and capa- bility of standing sudden changes of temperature. The manufactory has lately been suspended, and the causes of failure are unknown to the writer. YII. Soluble Glass . — This glass has been fully ex- plained in the first part of this book ; the various modes of manufacture, and various kinds, and the va- rious uses. It is stated a simple silicate of potassa or soda, or a double silicate of these two bases. This body is solu- CHEMICAL PROPERTIES. 277 ble in boiling water, without a residue, and scarcely affected by contact with cold water. The soluble silicated alkali, also called water glass, may be obtained in various ways, as also explained before ; at present, some large manufacturers employ powdered flints, which are dissolved in a caustic lye at a temperature of 300°. This water glass has found, lately, special application : 1. In protecting building stone from decay. 2. In hardening cements or mor- tar, so as to render them impermeable by water. And 3. For stereo-chromic painting. It is specially used as a protective varnish for pictures ; as a Are and rot proof coating for all building materials of organic origin, such as timbers, &c., and inorganic matter. The Chemical Properties of Glass . — Among the chemical properties of glass, there are some which merit an attentive examination : 1. The effect of the air or deoxydizing bodies. 2. That of water. 3. That of acids. 4! That of bases on glass. Air or oxygen, cold or hot, provided they are dry, exercise no action on glasses. Not so with moist air ; as has been stated above, the case is with the soluble glass. It is evident that deoxydizing bodies may act with the aid of heat on glasses which contain oxides of iron or manganese, especially lead. When plumbous glasses are heated with charcoal, or in a current of hydrogen, they very readily undergo a remarkable alteration ; the oxide of lead is reduced, and the metal being set free, communicates to the glass a blackish tint ; this effect is so rapid, that we cannot operate on crystal glass at the enameler’s lamp, without blacken- ing it greatly. 13 278 ART OF GLASS MAKING. The action of water is more or less on all glasses ; it tends to decompose it into a soluble alkaline silicate, and an insoluble, earthy and alkaline silicate. The water, which is boiled for a long time in glass vessels, becomes alkaline and turbid by the portion of earthy and insoluble silicates ; it is also very marked on crown, plate and window-glass. It is well known that looking-glasses tarnish some- times in the air, likewise optical instruments, owing to a deposit of a film of hygrometrical water. The windows of houses, offices or public buildings of an old date, often present a tarnished surface from the same cause stated ; glass tubes, globes, retorts, watch- glasses, when exposed to moist air, exhibit the same phenomenon. Action of Alkalies . — Concentrated solutions of all alkalies attack the glasses more powerfully than moist air. Action of Acids . ^ — The acids act on glasses with facility, particularly hydrofluoric acid, which acts in a peculiar manner ; the other acids tend to decompose glass, by seizing on the bases, and setting the silica free. Among the bottle glass, many resist the action of wine, and are powerfully attacked by nitric, hydro- chloric and sulphuric acids. A bottle glass, rich in alumina, is readily attacked by acids. Wines contain- ing much bi-tartrate of potassa, so quickly attack glasses, that the alteration is perceptible in a few weeks. The action of hydrofluoric acid is such, that it transforms the silica of the glass into water and fluoride of silicium. It attacks glass rapidly, and this property has been traced to account to etch glass in a PHYSICAL CHARACTER. 279 gaseous or liquid state ; the gaseous acid produces opaque traces, and the liquid acid transparent ones. The ])liysiGal characters of glass^ in relation to heat, may be stated, that all glass is fusible, but the temperature for different kinds are different. Oxide of lead or a large amount of alkaline silicates imparts more ready fusibility. Borax produces a similar effect. Bottle glass, containing oxide of iron and alumina and less alkali, is more difficult of fusion than other kinds. When melted glass is cooled, it is perfectly flexible, and plastic through a wide range of temperature, before it becomes cooled to rigidity. The softer kinds, especially flint or borax glass, when heated, begin to be plastic before a red heat, the others at higher temperatures, and the plasticity of all increases up to perfect fusion. When in the plastic state two pieces will unite together as firmly as if they were melted together. Some glasses are more mobile than others when in fusion. When glass is much softened by heat, it may be readily drawn out into rods or tubes, or if passed around a revolving wheel, into minute flexible threads. From its perfect mobility when fused, it may be cast into large sheets, such as plate glass ; from its plasticity below fusion, it may be moulded into any form by a few simple instruments, or by a mould of a given form ; from the firm union of two plastic pieces very complex forms are attainable. Glass conducts heat so imperfectly, that the end of a rod heated to whiteness may be held with safety by the hand within an inch or two of the heated end ; while this property is available for some uses, it is an inconvenience in other respects, which demands a remedy. 280 ART OF QLA0S MAKING. When a tumbler or other vessel of thick glass is cooled in the air, if it does not fly to pieces on cooling, it will readilj^ do so by dropping in a grain of sand or minute angular piece of Hint, while it may be struck a smart blow with a wooden mallet or other smooth body. Prince Kupert’s drops are pear-shaped pieces of glass, with a long thin stem, made by dropping melted glass into water. The bulb may be struck without injury; but if the smallest particle of the stem be broken off, the whole drop flies into powder with explosive noise and violence. These efiects are due to the bad conducting power of glass, combined with the cohesive force of its particles. Glass expands when heated and contracts on cooling, but as its particles move more slowly in proportion as it ap- proaches the cold, rigid state, the rate of cooling must be very slow to allow the particles to come uniformly close together. If suddenly cooled by dropping melted glass into water, the outside assumes the rigid and more contracted form, while the interior is still soft and expanded, from the bad conducting power of the glass. When thoroughly cooled, the interior must still retain the expanded state, so contrary to its cohesive force at common temperatures, and when the cohesion of the outer layer is in the least disturbed, as by a scratch or slight fracture, the whole of the cohesive force exerts its power to fracture the whole mass. These facts make it necessary to cool more slowly than can be done by the air, and give rise to the annealing process; the particles of the interior and exterior have then time to arrange themselves uniformly, according to their cohesive force at each SOLUBLE GLASS. 281 point of temperature, until they become perfectly rigid. When transparent glass is maintained for some time at a high heat, but below fusion, it becomes opaque or translucent, fibrous in structure, harder, less fusible, and a better conductor of heat and electricit}^ ; it is so much harder as to scratch glass, give sparks with steel, and will bear sudden changes of temperature like porcelain. As an example, we have the famous devit- rified glass as first prepared by Reaumur, and is more a crystaline glass, in distinction of ordinary amor- phous glass ; common bottle or window glass are most readily afiected. Although a portion of alkali is sublim- ed, yet the change is not dependent on the loss nor on the presence of any accidental impurities ; the altera- tion is wholly molecular, and consists in a re-arrange- ment of the particles in a crystaline form, where glass itself is entirely amorphous. ^ When crystaline glass is still more highly heated, it fuses, and then on cooling has the properties of amorphous glass, but requires a little higher heat for fusion, after each molecular change, which is due to loss of alkali. The different kinds of glass have different degrees of hardness ; bottle glass being the hardest, from the quantity of oxide of iron and alumina, and the smaller amount of alkali. Lead glass is softer and softer in proportion to the extent of oxide of lead ; an excess of alkali imparts greater softness ; the surface of the glass appears to be harder than the interior. Quartz, other hard minerals and a steel file scratch glass readily, and the diamond is generally employed, from its supe- rior hardness, to cut the glass. The curved facets of 2S2 ART or GLASS MAKING. the diamond crystal present also curved edges, and while the point barely enters the glass, the curved edges or shoulders act like a wedge to split the glass. Glass is very elastic, as may be shown by any strip of window glass, but more strikingly by hollow balls suspended by strings. The ring or sound emitted by glass on being struck is dependent on its elasticity. A glass harmonicon consists of small strips of window glass of different sizes, suspended on two parallel strings, and may be graduated to any scale. Goblets of various sizes are sometimes employed in a similar manner, and are made to vibrate, by passing the moistened finger around their upper edges. The discovery of glass is, without contradiction, one of the most important discoveries which accident or chemistry has rendered to civilization. Aside from its economical uses, it has exerted a singular infiuence on the progress of science. It is chiefiy by this aid that astronomy has attained a perfection so wonderful. By the aid of the misroscope naturalists have been enabled to study a host of phenomena, which hitherto escaped their notice ; the chemists could not perform any experiments without its use ; and to glass we owe chiefiy the present advanced state of the sciences, so fruitful in marvelous applications. The use of glass in our windows has introduced a degree of comfort into the meanest dwelling which previously did not appertain to the costliest palace. By means of the glass, the light is filtered from the wind, the rain and the cold ; the one can be enjoyed without being incon- venienced by the other. With the improved methods of warming we can create an indoor climate, adapted to the desires and feelings of the dwellers. The em- HISTORY OF GLASS MAKING. 283 ploymeiit of glass in many domestic articles of furni- ture contributes to cleanliness and health. A clean glass or decanter, water and other liquids, are physi- cally tested by the glass. Glass, which is so extensively applied and used to so many purposes, has never been the subject of investigation in order to establish the theory of its combination. The actual definition of glass is, that it is produced by the igneous fusion of silicious earth with certain alkaline earths or salts, or with metallic oxides. It is most probable that the name glass is derived from the latin w”ord glades; ice ; its resemblance to it has probably suggested its title. The art of blowing glass into bottles, making it into vases, tinging it to imitate precious stones, melt- ing it in huge masses to make pillars, polishing it into mirrors, and staining it in part, was perfectly known in the most remote ages. Pliny’s definition, that glass was discovered by some Phenician soda merchants, who ha,ving landed on the banks of the river Belus, served themselves with blocks of soda, which melting with the heat, transformed the sand on which they rested into glass, is very problematic, for it is well known what temperature is required for making glass. The Bible has reference to glass, and the Hebrews must have been acquainted with it while in Egypt. The Portland vase, which was composed of a deep azure glass, with figures of a delicate white opaque substance, raised in relief, was found in the tomb of Alexander Severus. It leaves no doubt that the art of glass making dates 3,500 years. The knowledge of glass making was .transferred from Egypt to Greece, thence to Rome and modern Europe. The introduc- 284 ART OF GLASS MAKING. tion into Italy was made by the Eomans after their con- quests ; into Asia, at the time of Cicero. Glass beads and amulets, and the art of glass making was known in Britain before its invasion by the Eomans. The glain neidyr, or Druidical glass rings, half as wide as our finger rings, but much thicker, have frequently been found ; and a superstition regarding them ex- isted, that they were produced by snakes joining their heads together and hissing ; and success was thought to attend any one who was fortunate enough to find one of these snake stones ; they were, evidently, beads of glass employed by the Druids, under the name of charms, to deceive the vulgar ; they are, usually, of a green hue, but some of them are blue, and others variegated with wavy streaks of blue, red and white. In Herculaneum, glass utensils have been found which date back to its destruction by the eruption of Mount Vesuvius, during the reign of Titus ; two panes of glass were found in a window at Herculaneum. In the year 220, a manufactory of glass was established in Eome. In the year 674, window glass was intro- duced in England, but for several centuries the use of window glass was exclusively confined to buildings appropriated to religious purposes, while the windows of houses were filled with oiled paper and wooden lattices. The skill of the Venetians in glass making was especially remarkable in the excellence of their mirrors, while plates of polished metal were used at the toilet in other countries. France began to manu- facture glass in the fourteenth century ; but not until the year 1701, did success attend its manufacture, under the direction of D’Agincourt. In the year 1557 HISTORY OF GLASS MAKING. 285 the manufacture of window glass was commenced in England, and Yenetian workmen were employed by the duke of Buckingham in 1670 at Lambeth, London. The first painted glass was executed in England during the time of King John. The Keformation greatly impeded the progress of the art; it nearly disappeared during the reign of Queen Elizabeth. A glass painter, named William Price, is said to have discovered and kept secret the art of glass staining, and to produce a rich, clear, bright and transparent red. In the United States the manufacture of glass dates as far back as 1790, by Eobert Hews, a citizen of Boston, who erected his factory in Hew-Hampshire for making window glass ; in 1800 another manufactory was established in Boston. The manufacture of flint glass originated in the Eastern States, and Hew- York and Pennsylvania followed it up, so that there are now at the present day 110 manufactories of flint and green glass, and 3>J manufactories of window glass and lamp shades, consuming as follows : Coal, over - 100,000 tons. Sand, - - - 10,000 iC Lead, - - - ‘ - 5,000 u Soda ash, - . - 6,000 u Nitrate of soda. 3,000 u Bicarbonate of soda. 1,000 u Binoxide of manganese, 200 u Coloring materials for buttons and ladies’ ornaments, such as zafire, cobalt, oxides of copper, tin. anti- mony, chrome, uranium, &c.. 10 ii White arsenic. 20 u 13 * 28G ART OF GLASS MAKING. The City of Pittsburgh contains the largest number of glass manufactories, on account of the cheapness of materials, such as coal and sand, which is at their command ; there are no less than 65 establishments for producing window, flint and bottle glass, 20 bottle and vial, 23 window glass factories, and a number of glass factories whose exclusive production consists of lamp chimneys, and one-half of the glass manufactured in the United States. Pennsylvania claims two-thirds of the entire production of the United States. Pitts- burgh consumes four millions of bushels of soft coal, and upwards of three thousand tons of soda ash annually ; employs nearly five thousand hands, who receive three millions of dollars in wages. The im- provements in making the glass are far advanced ; when formerly 200 feet of glass were made by a blower at a single blowing, now there are 800 feet made ; 8 x 10 was the largest size manufactured, now they are 40 x 70 ; formerly the thickness of the sheets averaged 18 to the inch, now they average 12, single strength ; their present double strength is about one- eighth inch thick. McCully & Co., manufacturers of green glass bottles, supply a proprietor of stomach bitters with 1,000 gross per month. There are a number of glass stainers con- stantly engaged there for steamboat furniture. The capital invested there is five millions of dollars. In JMew-York State there are about 12 glass facto- ries, in Massachusetts, 10. The Specific Gravity of Different Kinds of Glass. It may be of some importance to know the specific SPECIFIC GEAVITT. 257 gravity of glass, as it depeads on the component parts. Alkaline calcareous glasses are the lightest; bottle glass comes next, then plumbiferous glasses, and the following table : Bohemian glass, spec, grav., 2.396 Crown glass, “ 2.487 French plate glass, “ 2.48S Window glass, ‘‘ 2.642 Bottle glass, “ 2.732 Crystal, or common dint glass “ from 2.9 to 3.255 Optical dint glass, “ “ 3.3 to 3.6 White dint glass, “ , 3.000 Common green bottle glass, 2.715 St. Helen’s green glass, “ 2.654 Crown glass, “ 2.520 Leith Crystal, 3.189 English Plate glass, “ 2.439 As regards crystal or dint glass, the density may sufdce to givm a pretty exact idea of its composition ; it is, however, not so with the other kinds of glass, the difference of density of their constituents not being sufficiently marked ; for the relations vary from so many causes, that to establish them in a positive manner it would be necessary to limit oneself to certain glasses, and it would therefore be best to have recourse to a chemical analysis, the result of which will always be more reliable. TREATISE ON SOAP MAKING, THE ART OP ITS MANUFACTURE, WITH AND WITHOUT THE AID OF SILICATES, AND DESCRIPTION OP ALL KINDS OF HARD, SOFT AND TOILET SOAPS ; WITH TABLES OP THE COMPOSITION OF THE YARIOUS MANUFACTU- RERS, ETC., ETC., ETC. By Dr. LEWIS FEUCHTWAI^GER. Soap is a compound of salifiable bases with all fats and oils. When fats and oils undergo saponification by reaction with a salifiable base, the three principles contained in them, such as stearin^ margarin and olein^ are decomposed into oily acids peculiar to each, as discovered by Chevreul, a celebrated French chem- ist, in 1811, and called by him stearic, margaric and oleic acids, which unite with the base to form the soap, and a sweet principle, not saponifiable, called glycerin^ which is set free ; so that stearin is a stearate, margarin, a margarate, and olein an oleate of glycerin. Oils are mixtures of these three oily salts, and soaps are mixed stearates, margarates and oleates of various base. Steario acid is a firm white solid, like wax, fusible at 167°, greasy to the touch, pulverizable, soluble in alcohol, very soluble in ether, but insoluble in water ; it is used as a substitute for wax in making candles. Margaric acid has the appearance of fat or hog’s lard, which is fusible at 140°. Oleic acid is an oily liquid, insoluble in water, soluble in alcohol and ether. SOAP MAKING. 289 lighter than water, crystalizable in needles at a tem- perature below 32°, and having a slight smell and pungent taste. Glycerin, the product of the decomposi- tion, is a thick syrupy liquid, either colorless or of a slight amber color, without smell when pure, unctuous to the touch, and of a very sweet taste. There are soluble and insoluble soaps ; the soluble are combinations of the oily acids with soda, potassa and ammonia ; the insoluble consist of the same acids, united with earth and metallic oxides. The soluble soaps are only used as detergents, and are properly named soaps, while the insoluble soaps are emploj^ed in medicine, such as, for example, the lead plaster, and liniments. Soaps are mostly divided in hard or soft soaps ; the consistency of the fixed alkaline soaps depends partly on the nature of the oil or fat, and partly on the alkali present. Soaps are harder the more stea- rate and margarate they contain, and softer when the oleate predominates. The alkalies have, likewise, a different effect upon their consistency ; they are harder when formed with soda, and softer when con- taining potassa ; the pure soaps are generally the hardest and least soluble, while oleate of potassa is the softest and most soluble. Mutton suet, beef tallow and hog’s lard contain mostly stearin e and margarine, but also olein ; butters and other suets contain buty- rine or butyric acid. A great many vegetable and animal substances contain either one or the other of the above or allied acids, and are converted into soaps by their combinations with any alkalies or alkaline earths, and receive thus the name from the substances they are originating; such as we have a cocoanut oil 290 SOAP MAKING. soap, the product of cocoanut oil with lime ; wax soap, made in the same manner. Soaj^^ and the art of manufacturing it, has been known to the ancients ; the Romans followed it as a branch of industry, for they knew well how to use many vegetables possessing detergent properties, as also the virtues of alkalies, such as soda and kousa, a potash lye for similar purposes. Italy and Spain, in the eighth century, first established soap manufac- tories, and in the thirteenth century France followed up this trade ; and Marseilles began to manufacture the oil soap, having learnt to extract the oil from olives, which were abundantly cultivated there, and to combine the same with the ashes of their algae, thrown out from the Mediterranean Sea. England, in the sixteenth century, followed up the French method, but in place of the olive oil, employed tallow, in connection with potashes and salt. In later years, the English tallow chandler, or soap maker, conceived many improvements in his trade, by the introduction of rosin into his soap, which gave it many decided advantages. The great analytical chemist, Chevreul, among his many discoveries, studied the proximate principles, and made his in- vestigations known in 1811, and produced quite a revolution in this domestic art ; and from that period many new inventions and improvements have been introduced — both the machinery and application of heat ; for no soap can be produced without the proper heat, whether by direct fire, as formerly, or by or- dinary or superheated steam, as at present practiced ; also, the various ingredients, like the caustic soda, where formerly barilla and soda ash were entirely used ; 60 AP MAKING. 291 also, the time which was formerly wasted in prodnc* iiig soap, all of which form the improvements of the day in the manufacture of soap. The present soap maker operates systematically, uses his alkalimeter, in order to test the strength of his lye, and his ther» mometer, in order to hit the proper temperature when the heat required for saponification should be pro- duced, and measures the exact time when to abstract the heat and wdien to cool the mixture. Before proceeding to the manufacture of the various soaps, it is indispensable to state the different vehicles used in the process, the alkalies and lyes required for the saponification of fats, grease and oils. The appa- ratus used for boiling soaps consists in l)riclc kettles^ because they retain longest the heat during the opera- tion ; the foiling pan^ the upper part of which, con- sisting of a wooden curb fastened into the rim of the boiler, is now in general use, for the reason, as ample space is required for the soap paste to froth upwards, wdien superheated steam is employed. They are only used in large factories, wdiere from 100,000 to 130,000 pounds are weekly manufactured. Cast iron kettles are found at present in small factories, also the sheet iron kettles, which have the preference over cast iron kettles. When the manu- facture is conducted in open fire, common kettles must be so constructed as only the bottom undergoes the greatest heat, and not on the sides. Superheated steam is now, however, the only appa- ratus in the manufacture of soaps, at the boiling point temperature, when the heat is introduced directly into the material, while ordinary steam would have to be condensed through a worm, and the condensed vapor 292 SOAP MAKING. then to be discharged, and both time and fuel are much economized. Improvements are now continually made, both in machinery and materials. An appa- ratus, called Hubert’s, where two boilers are employed instead of one, as usual, in connection with super- heated steam, and when the lye and fat are introduced in both vats, steam in a superheated state is intro- duced, and injected into the entire mass. The steam jacket is also a late improvement, for the purpose of mixing and boiling of the soap ingredients simultaneously. The Alkalies. Potassa, either the crude, or jpearl ashes, are both, but mostly the latter, at present employed for cer- tain soaps. The first is also called potash or caustic potassa, and contains but 60 per cent, absolute alkali, while pearl ashes contain 50 per cent, of pure alkali ; the balance consists in sulphate and chloride potas- sium, phosphate and silicate of lime and other impu- rities, such as organic matter, .free silex and lime, &c., &c. The pot and pearl ashes are used in producing soft soaps or fancy soaps, for the reason they do not produce such hard materials which the soda com- pounds do. In former times potash, mostly in caustic condition, was employed in soap making, and by the addition of salt, the soap was made hard ; at present, however, potash or pearl ashes are mostly discarded in soap making. Soda, in the form of caustic soda, soda ash and sal soda, are all now exclusively used in soap making. Barilla, which is the crude soda obtained from the incineration of the kelp, is still used by some old soap THE ALKALIES, 293 makers in place of the caustic soda ; there is also a natural soda, called urao, used in South America, which is purer than barilla, on an average containing but 25 per cent. ; the same is, however, still in much use by the Spanish manufacturers, who bring the same in large quantities to England. The manufac- ture of soda ash, as obtained from salt, and transforma- tion into crude carbonate of soda, under the name of hlack ash^ its purification by lixiviation, evaporation and calcination, then assuming the name of soda ash or white ash^ is the process pursued in England. Eighty per cent, carbonate of soda is the mercantile standard corresponding with the English per centage of 48 per cent. ; 100 parts consist in 36 parts car- bonate of soda, and 64 parts in water of crystalization. Caustic soda^ which is now exclusively used by soap makers, is generally purer and more caustic than the last mentioned alkali ; it does not, however, bear much exposure, as it absorbs moisture from the atmosphere, and becomes fiuid unless soon used, and is accom- panied by a loss of material, but it is more certain and easier for operating on the materials. Sal soda or soda crystals form a very important adjunct in soap making ; they are mostly added after saponification has taken place, and for finishing by the operation called filling the soap. They are obtained by dissolving soda ash in ten times as much hot water, and allowing them to crystalize ; they are used for softening the water and washing purposes. In nature the carbonate of soda is found in many countries as an efflorescence on the soil and in the beds of dried up lakes. The writer saw some years ago in Nevada large districts of land covered with a 294 SOAP MAKING. white crust which was proved to be the carbonate of soda. In Carson valley miles of this alkali are spread over the surface. Carbonate of soda has latterly been extracted from the Greenland mineral, called cryolite, which is largely exported from that country ; it is extracted from cryolite by lixiviation, and carbonic acid passed through the solution, and the carbonate of soda left to crystalize. Cryolite, when mechanically cleaned and deprived of foreign substances, is employed in the manufacture of soap; it consists in 100 parts, of 13 alumina, 34 soda, and 54 fluorine, 30 by using the native minerals ; it is used for Ailing in. To TEST THE STEENGTH OF AN AlKALI. In order to ascertain the quality and strength of the alkali used in the manufacture of soap, it will re- quire a thorough chemical knowledge, which cannot be expected from a soap maker ; but as it is of the high- est importance to guard against imposition, and in the preparation of his lye, to learn the exact proportions for adding to the alkalies, it is necessary to give some short instruction on the subject. The following points must be observed in the pur- chase of caustic soda, soda ash and potassa : 1. The water which is frequently left in the alkalies in order to increase the weight; 2. To estimate the amount of caustic and carbonated alkali. By heating 100 grains of the alkali over a gas lamp in an iron ladle for a short time, until all water is expelled, which can be ascertained by holding a cold glass plate for a mo- ment over the ladle, when whatever vapor arises from STEENGTH OF AN ALKALI. 295 the heated material will be condensed on its surface ; the net weight will indicate the amount of water in the above quantity. As all alkalies are used in a caustic state, so it re- quires its estimation, which is done by treating fifty grains of commercial soda, finely ground, with half an ounce of strongest alcohol in a porcelain capsule ; shake them well together, decant the liquid, and evaporate it quickly until it has become quite dry ; weigh when cool, and ascertain the actual amount of caustic soda which the fifty grains at first used have lost ; it is understood that you have tared the porce- lain dish with the sample of soda, and that you deduct afterwards the weight of said dish, as soon as the operation is completed ; now twenty grains loss would make the loss forty grains on one hundred grains of the sample. In order to estimate the amount of car- bonated alkali, it is indispensable to ascertain first the quantity of either soda or potash, and then convert by calculation the value of the carbonated, which is done by dissolving fifty grains in a flask containing two ounces of water ; then add from one hundred grains finely powdered oxalic acid to the alkaline solution so long, until a little strip of litmus paper becomes slightly reddened, the liquid being kept hot. The residue of the oxalic is then weighed, and the loss ascertained ; if the loss is forty-three grains, then fifty- seven grains were consumed in the neutralization ; it is known that 7.87 grains of oxalic acid are capable of saturating five grains of caustic soda, or seven grains of caustic potassa ; five grains of caustic soda are equivalent to 6.62 grs. of carbonate of soda, and seven grains of caustic potassa are equivalent to 8.63 car- 296 SOAP MAKING. bonate of potassa; 16.2 grains caustic soda are now equivalent to 21.5 grains of carbonate of soda, which, when doubled, gives the quotient of forty-three per cent. As we have found 10 per cent, water, 40 per cent, caustic soda, and 43 per cent, carbonate of soda, the balance of the one hundred grains soda ash must be seven grains as foreign substance. For ascertaining the nature of foreign substances contained in a soda ash, such as a chloride or a sulphate, more chemical knowledge is required ; but a few drops of nitrate of silver added to a clear solution of the suspected sample, which has been a little acidulated by nitric or sulphuric acid, will at once prove the presence of salt, which is chloride of sodium, or of a chloride of potassium, by a white flocky precipitate being formed ; a sulphate may be detected by first neutralizing the solution of the suspected sample with a few drops of nitric, and then adding a few drops of chloride of barium, whereby a fine heavy white pre- cipitate is formed. The Alkalies are made into Lyes. The soft waters, and those from rivers and springs, and free from organic matters, ought only to be used for the preparation of lyes. Under the word lye, we understand the aqueous solution of caustic soda, or potassa, prepared from the common soda ash, or the crystals of soda, which are converted into the caustic state by means of lime-water, whereby the carbonic acid of the alkalies unite with the lime, forming insoluble carbonate of lime, which settles at the bottom ; the whole operation is per- MAKING ALKALI INTO LYE. 297 formed in a large kettle containing hot water. The caustic state of the Ije is ascertained by taking out a few drops, which must not effervesce with any acid ; if found neutral, the lye is left to settle for twelve or fifteen hours before using it in the soap kettle ; the lime required for the lye must be the fat lime, and twenty-four pounds of quick-lime are requisite for one hundred pounds of crystalized soda, while sixty pounds of fat lime are required for one hundred pounds of soda ash. If pearl ashes are intended for producing a lye, forty-eight pounds of fat lime are necessary for one hundred pounds of pearl ashes ; an excess of lime does not produce an injury to the lye. The strength of the lye must be ascertained by Baume’s hydrometer, which, however, only indicates the relative strength of the lye, with all impurities, yet is a sufficient guide for making it into soap. The following table exhibits the quantity of fused potassa and solid caustic soda in one hundred parts of lye, with their respective degrees, after Baume’s hydrometer : j Degrees. 1 Specific Gravity. Potassa in 100. Soda in 100. 1 40 ° 1.357 33.46 32.40 35 ° 1.299 29.34 28.16 30 ° 1.245 24.77 22.58 25 ° 1.196 20.30 17.71 20 ° 1.151 16,40 13.77 18 ° 1.134 14.38 12 . 1 16 ° 1.117 12.29 10.26 14 ° 1.101 10.59 8.85 12 ° 1.085 9.20 7.69 10 ° 1.070 7.74 6.49 8 ° 1.055 6.25 5.46 6 ° 1.041 4.77 4.02 4 ° 1,027 3.21 2.92 2 ° 1.013 1.63 1.38 0 ° 1.000 — — 298 SOAP MAKIKG. In certain cases, it is requisite to transform stronger lyes into weaker of a definite degree of strength. Though, to effect this, much precision is needed ; still, we think the reader will find little, if any difficulty, after perusing the annexed part, containing four tables for the reduction of strong lyes, published by Mr. Eu- gene Lorrne, the excellent author of the work “ Manuel complet du Savonnier.’^ The first column at the left of each table shows the quantity and the degree of the lye to be diluted. The second indicates the quantity of water to be added to the lye. The third gives the amount of the lye obtained by the admixture of both liquids ; and The fourth exhibits the areometric degree of the lye. TABLE I. Showing the different areometric degrees resulting from a mixture of 10 gallons of soda lye, of 36 degrees^ Baume, with quantities of water mrying from 10 to 60 gallons. Number of gallons of Lye of 36 degrees. Number of gallons of Water. Number of gallons of obtained Lye. Areometric degree of the Lye. 10 10 20 23 10 20 30 17 10 30 40 14 10 40 50 12 10 50 60 10 10 60 70 9 10 70 80 8 10 80 90 10 90 100 6i 10 gallons of lye, of 36 degrees Baume, weigh 112^ lbs. TABULAR STATEMENT. 299 TABLE II. Showing the different areometric degrees resulting fro7n a mixture ofV) lbs. of soda lye, of 36 degrees Baume, with quantities of water varying from 10 to 100 lbs. NumlDer of pounds of Lyel of 36 degrees. NumlDer of pounds of Water to be employed. Number of pounds of Lye obtained. Areometric degree of the Lye. 10 10 20 21 10 20 30 14i 10 30 40 Hi 10 40 50 10 10 50 60 9 10 60 70 8 10 70 80 10 80 90 4i 10 90 100 5 nearly. 8.8 gallons of lye, of 40 degrees Baume, weigh lOO lbs. TABLE III. Showing the different areometric degrees resulting from a mixture of 10 gallons of soda lye, of 30 degrees Baume, with quantities of water varying from 10 to 90 gallons. Number of gallons of Lye of 30 degrees. Number of gallons of Water to be employed. Number of gallons of Lye obtained. Areometric degree of tbe Lye. 10 10 20 19 10 20 30 nearly 14 10 30 40 11 10 40 50 9 10 50 60 8 10 60 70 7 10 70 80 6 10 80 90 5 10 90 100 4i Piemarks . — 10 gallons of soda lye, of 30 degrees, weigh 100 lbs ; 75 gallons of this lye, and 25 gallons of water, give 100 gallons of lye of 25 degrees Baume. There are 23J lbs. of caustic soda wanted for making 10 gallons of lye of 30 degrees Baume. 300 SOAP MAKING. TABLE IV. Showing the different areometric degrees resulting from a mixture of 10 lbs. of soda lye, of 30 degrees Baume, with quantities of water mrying from 10 to 90 lbs. Number of pounds of Lye of 30 degrees. Number of pounds of Wateri to be employed. Number of pounds of Lye obtained. Areometric degree of the Lye. 10 10 20 17 10 20 30 12 10 30 40 n 10 40 50 10 50 60 6i 10 60 70 5i 10 70 80 5 or 5i 10 80 90 4i 10 90 100 4 9.6 gallons of lye, of 30 degrees Baume, weigh 100 pounds. The saponifiable oils and fats for the mannfactnre of all kinds of soaps are from the vegetable and ani- mal kingdoms ; the fats or fatty acids which, as already explained, consist of margaric, stearic and oleic acids, in combination with the oxide of glyceril in various proportious, we find the margarin principally in but- ters, and not drying oils ; the stearin in the suets, and the olein forms the liquid portion of most animal and many vegetable fats ; we also find the palmitin, which bears some resemblance to stearine, but is principally contained in palm oil, and which contains the acid in a free state, (not having any glycerin,) and for this reason possesses many advantages over other similar substances in the manufacture of soap. Fats contain also animal tissues, albumen, pigments, and frequently peculiar acids, and thereby producing peculiar odors. PALM OIL. 301 of wliicli organic chemistry gives hundreds of exam- ples. Mutton fat and goose grease owe their peculiar strong odor to another acid, called hircine. The vegetable fats or oils are numerous and of different consistencies ; they are all lighter than water, of a specific gravity of 0.9 to 0.919, and all insoluble in cold and hot water, easily soluble in ether, and all possess a sweet taste ; many of them undergo changes, some solidify, others thicken and become hard, but retain their brilliancy ; they have therefore been class- ified with fluid and non-siccative oils. Linseed, hemp- seed and poppy oils belong to the first, and olive, palm, sweet, almond and cocoanut oils belong to the latter class. Cocoanut oil^ also called cocoanut butter, is found in a liquid state in the nut of some palm species in the southern or tropical hemispheres, such as Brazil, Ceylon and many Pacific States. It yields 60 per cent, of the fatty acid ; it is white, sweet, and of the con- sistency of lard, mild taste and agreeable odor ; it melts between 60° and 70° Fahr., and becomes easily rancid. It forms hard soaps, although it sapon- ifies but slowly, and is therefore mixed with either tallow or palm oil, both of which are improved thereby, as it increases in emollient properties, and gives a brilliant whiteness to tallow soap. Palm Oil . — Several varieties of palm trees yield the fruit containing the oil or butter. South America, Africa and the East Indies are the localities from where the extracted oil is brouglit to this country. The color of palm oil varies much, according to several circumstances, either of orange or even of violet. Palm oil is prepared from the fruit of the palm II 302 SOAP MAKING. tree {Clceis Qxiineensis) as follows : — On its arrival at maturit}", the fruit is plucked and thrown into a heap on the ground, where it is left for about a month. Fermentation is thus produced. When this is suffi- ciently advanced, the mass is thrown into large iron vats and boiled with water, the fruits being crushed in the hands of the laborers from time to time. After prolonged boiling, they are pounded in rude mortars formed from the trunks of trees, the kernels are removed, and the shells again boiled. The oil then floats on the surface of the liquid, and is collected with large wooden spoons. Properties , — Palm oil is solid at the ordinary tem- perature of our climates ; its color is a reddish yellow, and is esteemed in proportion to the deepness of its color. Its perfume resembles that of the iris or the violet. It melts at from 30° to 35° G., according to its age, but when freshly prepared its melting-point is lower. It is easily soluble in alcohol, and still more so in sulphide of carbon and ether. About 80,000 tons are annually manufactured. The oil mixes readily with water, which is frequently used to adul- terate it; 50 per cent. 'may be added without fear of detection by the most practiced eye. In order to estimate the water contained in palm oil, a certain weight of it must be heated on a stove at 110° C. ; desiccation will then ensue in a few hours. Unadul- terated commercial palm oil contains from three to eight per cent, of moisture. A very superior quality of oil is obtained from the kernels of the palm, which are very large. Ash . — Sand or earth is frequently mixed with palm oil during manufacture. To estimate this, calcine 50 IMPURITIES. 303 grins, of oil in a porcelain capsule, and after the char- coal thus formed is burnt off, weigh the ash obtained. Palm oil sometimes contains from four to live per cent, of sand. Imjpuriiies . — Sundry organic substances, such as the remains of palm leaves, etc., also occur. In order to estimate these, melt 100 grins, of oil in a capsule upon a water-bath, let it stand an hour, decant the limpid oil, and treat the precipitated impurities with sulphide of carbon, so as to dissolve the oil which adheres to the sides of the vessel. The impurities must be thrown on a filter, washed with sulphide of carbon, dried at 100°, and weighed. Some analysis are subjoined : Loss IN Palm Oil. I. II. Moisture, 8.25 3.12 Ash, 0.45 1.20 Organic impurities. 1.01 0.80 Total loss. 9.71 5.12 Palm oil produces a beautiful soap. It is mostly employed after having undergone a bleaching process, which is effected in the following manner : The yellow palm oil is heated in a wooden tank to 120° Fahr., chromic acid in its purity is then added, or five pounds red or bichromate of potassa dissolved in hot water is put in the tank under much agitation, and ten pounds chlorohydric (muriatic) acid and two and one- half pounds oil of vitriol, all of which is the propor- tion for 1,000 pounds palm oil to be bleached ; after a 304 SOAP MAKING. little while the process is completed and left to settle, the oil appears perfectly decolorized, and produces a soap of most brilliant whiteness, and is employed with tallow, about 20 per cent, to 100 of the latter, and is also a great deal used in the rosin soap, for the purpose of covering the flavor and brighten the color of the latter. Olive Oil . — It is imported from the southern ports of Europe, and is obtained from the fruit of the olive tree. The virgin oil is the best oil obtained from fresh gathered fruit. Olive oil is often adulterated with cheaper and also animal oils; it makes the best soap. The well known Windsor and Marseilles soaps are produced with it. Oil of Poppy . — The bruised seed of the poppy plant produces a flne oil ; it remains liquid to zero, Fhr., is a drying oil. It is used in France, combined with tallow, for the imitation of Marseilles soap. The following vegetable butter, such as the golam^ a product of an African tree, of a reddish white color, and containing 82 per cent, stearine, and another butter from the African butter tree. The stillingia butter is imported from China ; it is white and harder than tallow. The tree grows in the valley of Chusan. The mofurra tallow from Madagascar, extracted from the kernels, which are of the size of a cocoa bean, is of yellowish color, and in odor similar to cocoa oil; it forms a brown soap with alkalies. The Animal Fats. They contain more stearine and margarine than the vegetable fats, and are distinguished by their color. ANIMAL FATS. 305 odor and consistency. There is much difference in the consistency of the animal fats. The fat or oil of whales is generally fluid, that of the carnivorous animals soft and rank flavored, and in the ruminants nearly scent- less. Xor is the degree of firmness the same in all parts of the organism ; the fat from the kidneys is generally harder and more compact than that in cellular tissues and bowels of animals, and the fat of the female is generally softer than that of the male. The color and odor of the fats have an influence in the manufacture of soap. Beef Tallow . — This animal fat is well known ; that rendered by steam is generally the whitest, has a yellowish tint, which may be removed by several washings in hot water ; it is firm and brittle; its melt- ing point is 111° Fahr., and becomes solid at 102° Fahr. The tallow from different countries are brought to market and command a different price, such as the Fussian, South and hfortli American. Mutton Suet . — It is richer in stearine than beef tallow ; when the fat is stale the smell is most disa- greeable and nauseating. It is generally compact, firmer and whiter, and of less odor than beef tallow. It yields a beautiful wdiite soap when saponified with soda lye, but may become too hard and brittle on account of its richness in stearine, and in the saponi- fication about 20 per cent, lard oil is added. Lard or Hoffs Fat . — By freeing the adipose matter of the hog from the membranous, and melting it at moderate heat, so as to separate the fat from the cracklings, we obtain a fine lard, which has agranular appearance and can be pressed for oil without any further manipulation. That from hogs which have 306 SOAP MAKING. been corn fed has the greatest consistency ; it has, when fresh, a mild and agreeable taste. The consistency of butter and its melting point is at 81° Fahr. ; consists of 62 per cent, liquid fat or olein, and 38 per cent, solid fat. It yields a fluid called lard oil when gran- ulated and pressed at a low temperature. The pressed cake, consisting chiefly of stearine, is termed solar stearine, and used exclusively in the manufacture of candles ; it forms a white, sweet and pure soap. Horse Fat. — It is mostly extracted by steam from different parts of dead horses ; it is from a white to brown color, and every horse yields about one hundred pounds. The soap from horse fat is white and Arm, but has a very peculiar odor. Bone Fat , — Fresh bones are used for extracting the fat, which is about 5 per cent. ; it permeates the bones when kept for some time, and makes the extraction very difflcult. It is recommended for purifying and deodorizing bone fat, by means of saltpetre and sul- phuric acid, which are melted together ; will pro- duce a fat of a light yellow color. Fish Oil . — The fat of several species of the whale fisli, such as the cachelot, pot-flsh, the Greenland whale, the Antarctic whale, difierent dolphin species, the norwall, the sea-pore, and several species of ribbon and mammifera belong to one class of whales, and they all have their specific names. The white-fish oil is an oil which flows out spontaneously from the fat heaped up in a reservoir. The name of train oil alludes to the foiled fish oils^ which are of inferior quality. Fish oils are used as a burning fluid, for soft soaps, adultera- tion of other oils, and the manufacture of chamois leather. ELAIDIC ACID. 307 Sperm Oil and Spermaceti. In the head, and special cavities of the head of several sperm whales, especially of the pot-fish, or cachelot, and of some dolphins, there is a liquid fat, which, after the death of the animal, a large quantity of white, firm, tallow-like substance is separated ; the liquid part is called sperm oil, and the solid sperma- ceti ; the first is. brought in commerce, bleached or unbleached, wliile the latter is more used for the manufacture of candles. Oleic Acid. This acid comes in trade under the name of red oil ; it is a product from the manufacture of adamantine candles. Two kinds of red oil are brought into market, one formed by the process of distillation, which, owing to its disagreeable odor, is used for soft soap ; the other, obtained by pressure, yields hard soaps, either alone or mixed with tallow or other fats. It is the product from stearine, called stearine cake ; the first contains some oil vitriol, and has to be washed before using it. Elaidic Acid. If oleic acid is treated with hyponitric or nitrous acid, a pearly white crystaline substance is obtained, of the consistency of tallow, and is called elaidic acid. It is used with benefit in soap and candle manu- facture. 308 SOAP MAKING. The Manufactuke of Soap. For the purpose of the boiling of the soap materials, it is indispensable to produce a preliminary combina- tion of fat and lye ; and in order to form a union of the fats with the lye, the latter should be perfectly pure; and the same may, during this first operation, be of the same strength, or be commenced with a weak lye, then of middle strength, and finish with a strong one ; tlie first may be from 10 to 15° B., and the second to begin with one of 7 to 10° B. ; 15 to 18° B. ; and lastly, 18 to 20° B. In the manufacture of red oil soap, very strong lyes are employed, from 25 to 30° B. Usually, the fat is first put in the pan, and then the lye is added ; but it is absolutely necessary that the lye be caustic and not carbonated, which will not decompose any fat, and therefore not unite. By transforming one hundred pounds of fat into soap, fourteen pounds of caustic soda are necessary, generally more is employed ; it is gradually and in small quantities added, as a large quantity of lye added at once will never act so energetically upon the fat as might first be supposed. When one-quarter of the lye is added in the beginning, it soon forms with the fat a milky liquid, which, in heating, gradually be- comes clearer, producing a transparent soap solution, with intermingled fat drops ; more lye is added under constant stirring, until the entire quantity of the same is consumed. This operation is called the pasting^ for it displays a uniform clear mass, where neither lye nor fat can be distinguished. It shows, moreover, that the right proportion of fat and lye have been em- MANUFACTURE OF SOAP. * 309 ployed. When the spinning of the soap makes its ap- pearance, that is, when the paste no longer drops from the stirring rod, but slides down in long threads, the operation is complete. The second operation in the rnannfactnre of soap is the salting process, to add dry salt, or the same in solution, for the reason that soap is insoluble in brine or strong caustic lyes, while weak lyes dissolve it ; this operation is also called the “ cutting up the pan.” Upon this principle the mainne soap is manufactured from the cocoanut oil soap, which is so serviceable for washing in salt water, as this soap possesses the re- markable property of being dissolved by a brine solu- tion. The salting operation is effected by gradually stirring the paste wdth a stirring rod from below, up- wards, through the brine or dry salt. Twelve to six- teen pounds of salt are necessary for one hundred pounds of fat, and after half the quantity of this salt is added, the soap ought to be boiled up for about ten minutes. The separation is perfect when the water is observed to run off from the curdy mass, and when on placing some of the soap in the palm of the hand and rubbing it with the thumb, it hardens into firm scales ; or when the surface splits up into several fields, sepa- ted from each other by deep furrows; the soap which was covered with froth and bubbles suddenly sinks, and the froth breaks up into roundish massive grains, distinctly separated from each other and from the saline solution. The mass shoiTld be left quiet for several hours, and the under lye (nigger) drawn off by the faucet. The third operation is the clear boiling of the soap, so as to obtain hardness, consistency and complete 14 ^ 310 SOAP MAKING. neutrality of the soap. The paste is boiled gently with tolerably strong lyes, in certain proportions, and boiled for eight hours; the lye is then drawn off, and a second boiling with lye is undertaken and drawn off again ; a quick union of the alkali with the fat is thereby obtained ; the process is terminated when large, regular and dry scales appear on the surface, which are easily pulverized by rubbing them in the palm of the bands ; the soap should then be covered, left for some time, and eventually removed iu the ladles. Saponification by Pbessube and Agitation. The latest improvements in saponification consist either in pressure or agitation. The first is Rogers’ patent process, where the agitation is performed at a low temperature, and not alone, as much time is saved to produce a thorough saponification, but also the bleach- ing of the soap is affected, so that inferior stock may be employed in the manufacture of soap. According to him, is the following : Into an iron tank the mixture is put, and then forced by means of a force- pump, and a pressure of about 400 pounds to the square inch ; the mass is forced into a cylinder by steam ; here it remains until complete saponification is effected ; it is then drawn off in cooling frames and treated in the usual manner. This process has many advantages ; the product is much firmer and more translucent soap, and the caustic soda may be substi- tuted for carbonate of soda, even in smaller propor- tions. Saponification by agitation is effected by an appa- ratus, consisting in a cylinder, six feet in diameter PROCESS OF SAPONIFICATION. 311 and twelve feet long, and capable of working two and one-half tons of tallow with twenty gallons of lye, of 1.125 specific gravity, forcing 100 pounds tallow through the cylinder lengthwise ; a shaft extends with radiated arms, to which an oscillating or rotary motion is communicated ; agitation is kept up for three hours, the mass is then left undisturbed for a short time, and then removed into an open boiler, and com- pleted in the ordinary way. The following processes were reported by the commissioner to the Paris Expo- sition in 1867 : The De Milly and Motard Process of Saponi- fication. After the lime soap is formed, it is decomposed by sulphuric acid, and the resulting fatty acids are cooled in shallow tin or copper pans, in rooms of about 60° Fahr., so as to allow of the proper crystalization of the solid acids. The next step is to press these acid cakes, which is first done in a cold press, then in a hot press, first suggested by Cambaceres, but success- fully carried out by the horizontal presses invented by De Milly and Motard, and now universally employed in candle factories. The difiiculties, however, of these indefatigable manufacturers, were far from being overcome ; the pans colored the fats with iron, the last trace of lime was not removed, and the candle made had a crystal- ine ^itructure. By the alternate application of steam and dilute sulphuric acid, and white of egg and oxalic acid, they overcame the first difficulty. \^arious means were tried to prevent the crystaline structure. 312 SOAP MAKING. commencing with the objectionable use of arsenious acid, then the more expensive one of wax, w'hich also had a tendency to color the candle They at last triumphed over this difficulty, by cooling the acids to a temperature near their point of solidification before introducing them into the m-olds, that were first raised to the temperature of the cooling fats. During the cooling of the mass it is constantly agitated, and a pasty liquid is produced, which congeals in the molds without crystalization. Three years had now elapsed since the first establishment of their factory, the com- mercial results of which had been a failure. M. De Milly now came into the possession of the factory alone, his faith in its success remaining firm, and two years later, in June, 1836, he gave the perfecting touch to the successful manufacture of star candles. The wick has always been a source of great annoyance in the burning of the candles, for the small amount of mineral matter in the candle stuff would accumu- late in the wick, and interfere with the free flowing of the melted fat. After numerous trials by saturating the wick with different substances, the required result was successfully accomplished, by impregnating the wick with a certain quantity of boracic acid, dissolved in water, containing one-thousandth of its weight of sulphuric acid. The boracic acid, as the combustion of the candle progressed, united with the lime and the ashes of the wick, forming a very fusible salt, which accumulated on the end of the wick, forming a small drop. SULPHURIC ACID SAPONIFICATION. 313 Sulphuric Acid Saponification. This method was discovered by Chevreiil in his original researches on fatty bodies; and in the patent taken out by him in conjunction with Gay Liissac, in 1825, this method is specified, but certain portions of the fats were so altered, as to discolor the product to such an extent as to render it of no use in practice. The acids, however, thus formed, could be distilled more or less perfectly, as lirst shown by Chevreul, and subsequently practically executed by Dubrunfaut. But the first idea of combining the two operations, viz., sulphuric acid saponification followed by distilla- tion, is due to Coley Jones and Wilson, of England, subsequently perfected by Gwinne and Jones. The process, as it is now carried out, may be summed up as follows : The fat is placed in large vessels, that may be of wood or masonry, lined with lead, and from six to fifteen per cent, of concentrated sulphuric acid is added ; the mixture is then heated by a steam coil, to near the temperature of boiling- water, and maintained at that temperature eighteen or twenty hours. Some, however, operate at a higher temperature, and consume less time in the reaction, with as much as thirty per cent, of sulphuric acid and agitation, decomposing batches of two hundred pounds in four minutes. The fat is decomposed with an alteration of part of the glycerine and part of the fat, sulphurous acid and carbonic acid being evolved. The black mass resulting from the action of the sulphuric acid is now thoroughly washed by boiling water, until all the fatty acids are freed completely from sulphuric acid. The fatty acids are now introduced into larg( 314 BOAP MAKING. cast-iron stills, capable of holding over one ton of these acids. The stills are heated from below, so as to bring the contents to the temperature of 260° C., when a jet of superheated steam of 350° to 380° C. is made to traverse the charge, and in about twelve hours the matter is distilled over, leaving behind a pitchy substance, which may be used in the manufac- ture of gas, or for coating roofs, and other purposes in the arts. The fatty acids, when distilled, may be cooled in pans, and submitted to the cold and hot pressure ; for some purposes it is submitted only to the cold pressure, and in England is much used with- out any pressure at all, when palm oil has been the fat acted upon. Saponification by Sulphuric Acid without Distillation. Fats saponified by sulphuric acid by the ordinary method, contain more or less tarry matter, arising from the decomposition of the fats, causing more or less loss in the raw material. M. De Milly undertook a series of experiments, by which he finally showed that fats could be saponified by sulphuric acid without the formation of tarry matter. This point being established, he further showed that the fatty acids obtained without the formation of tarry matter, were identical with the fatty acids formed by the lime saponification. These he submitted to cold and hot pressure under special conditions, and obtained cakes of candle stuff most beautifully white. As to the oleic acid, it is of a dark color, but in no way decomposed ; it makes a fine brown soap, or it can be distilled and made white. MANUFACTURE OF FAMILY SOAPS. 815 M. Balard, in a report on this process, expresses himself in the following terms : “ In the establishment of M. De Millj, the fat is melted and heated to 120® 0. ; it is then allowed to flow from its reservoir and mix with a stream of strong sulphuric acid, in the proportion of six per cent, of the latter. The mixture is rendered perfect bj means of agitation. The action takes place immediately, and is arrested in two or three minutes, by allowing the mixture to flow into boiling water, when the sulphuric acid and unaltered glycerine enters into solution, and the fatty acids float on the surface, being of a dark color. But, contrary to what takes place in the ordinary method of saponiflcation by sulphuric acid, the coloring matter is completely soluble in the liquid fat acid, so that by cold and hot compression, the solid fat acids are obtained perfectly white, ready to be molded into candles. The entire operation can be accomplished in one hour.’^ The Manufacture of Family Soaps, There are generally four different kinds of soap brought into market, which consist in — 1. Hard ; 2. Soft ; 3. Toilet or perfumed ; and 4. Silicated soaps. The hard soaps are invariably made from soda ; they are divided in boiled soaps and those made in the cold way. Another division is made among hard soaps, such as grained^ or those where the separation of the underlye (nigger) has been made, as has been already noticed under the head of cutting up the pan, and in filled soaps, or such where the whole contents of the boiling pan are kept and crutched together, 816 ^OAP MAKING. and sold as soap. The more solid constituents a fat contains, the harder is the soap, and the more oleine, the softer. In mixing the fats in different proportions, soaps of every consistency are obtained. Weak and middling strong lyes will produce a light soap, while lyes of 25° to o0° B. will produce a soap heavier than water. Glauber salt, not over one per cent., is some- times added in order to prevent too great solubility uf the soap in washing ; it is called then ElectriG Soap. — Bosin, in the proportion of one- third or one-fourth of the fat employed, is frequently used, and the soap is called Rogers’ soap. Twelve and one-half pounds of solid caustic soda are usually consumed for 100 pounds of fat, for its conversion into soap. A new soap, composed of the rosin soap, to which is incorporated a mixture of spirits of tur- pentine, ammonia and pearl ashes, and by other man- ufacturers a quantity of flour and benzine are added to the above mixture, and all crutched in the rosin soap. Tallow Soaps. The most ancient, and at the same time the most important, is the tallow soap; it is cheap, and called for by everybody, both in the household and the man- ufactory. The following is the mode pursued by the most experienced soap makers : To 1,000 pounds fat, which is melted at a slow heat, from 70 to 80 gallons lye, standing 10 to 12° B., are added and kept stirring under a gentle fire for several hours. Should a part of the fat separate from the mass, which is often the case, an oily liquid will be observed floating on tlie top ; it requires then the addition of 35 to 40 gallons TALLOW SOAPS. 317 more Ije, of 15 to 18° B., whereby the whole contents will form quickly a homogeneous mass of a grayish white color ; a gentle boiling must be kept up for several hours, and adding every hour six to seven gal- lons of lye of 20° B., when the paste assumes the proper consistency ; this operation requires ten to twelve hours. And then the second operation has also been described under the salting process, w^here the ingredients have to be well stirred while adding the salt, and after separation has taken place, several hours are necessary for settling ; and then to draw off the colored underlye, 90 gallons of lye of 25° should then be added, and the heat increased, so as to preserve the soap from bubbling. The wdiole mass is then boiled from ten to twelve hours, adding every hour five gallons lye of 25° B. ; but after boiling four to five hours, the operation is perfected, and the fire with- drawn, left quiet for an hour, and the underlye is drawn off ; the soap will then separate from the lye and rise to the top ; after five to six hours, while yet liquid, it is put in pails or ladles, into the frames, taking much care that no lye is mixed with it. In the frames, which are either of wood or iron, it must be well stirred and crutched for some time. In order to cover the not agreeable smell of the tallow, two ounces of oil of mirbane should be added to every 100 pounds of soap ; after seven to eight days it may be cut. 100 pounds of tallow^ will yield from 165 to 170 pounds of soa]>. Tallow Eosix Soaps. It is well ascertained that the addition of rosin, to a certain amount, will make the soap more detergent. 318 SOAP MAKING. more soluble and cheaper ; it does form a soap with the tallow ; 15 per cent, rosin, and 85 per cent, tallow, make a good proportion ; any excess will depreciate the soap in firmness and quality ; the soap will become clammy if 33 per cent, are used ; it will be too soft ; but twelve gallons of lye of 30° B. may be used for every 100 pounds of rosin ; it may be melted with the fat in the commencement of the boiling for soap, although it is more expedient to make first the tallow soap, and then mix the rosin soap, compounded in another kettle, to the first. Both soaps have then to be well stirred and beaten thoroughly for half an hour, and then passed through a sieve, before they are filled into the frames, where they are also well stirred and crutched. By adding to the saponified tallow some palm oil, the appearance of the soap will be thereby much improved. A practical soap maker stated to the writer a short time ago, that he uses ten pounds of tallow, nine pounds of rosin, and five pounds of tilling of sal soda and starch, which he adds after the saponification has taken place. CocoANUT Oil Soap. This oil, as already mentioned, acts dififerently from any other fats, in combination with which weak lyes produce a milky mixture. A lye of 27°, when cold, will saponify 100 pounds cocoanut oil, and produce 200 pounds soap. The process is very simple : the oil and lye are put together, and the heat is applied ; after stirring for one or two hours, the paste is seen thickening gradually, and the heat is moderated while CASTILE OR SPANISH SOAP. 319 tlie stirring is continued. After a while the paste be- comes transformed into a white semi-solid mass, which forms the soap, and this has to be filled immediately into the frames, as solidification quickly ensues. Equal parts of tallow and cocoanut oil, or only cocoanut and palm oil, (bleached,) yield a very fine soap ; also, 90 to 95 per cent, cocoanut oil with 5 to 10 per cent, natural palm oil, yield a fine soap ; the saponification takes place of fats and cocoanut oil, if not in too large a proportion. It is to be remarked, that the mixture of cocoanut oil and other fats and lye need not be separated with brine. Castile or Spanish Soap. This is also a hard soap, a pure olive oil soda soap, and is imported here under two principal varieties, the white and the marbled. The white Castile soap is of a pale grayish white color, does not give an oily stain on paper, devoid of rancid odor or strong alka- line qualities, entirely soluble in water and alcohol. It becomes dry by exposure to the air without dis- playing any efflorescence ; it contains 21 per cent, water. The marbled Castile soap is harder, more alkaline and more constant in its composition, and contains but 14 per cent, water ; it is, therefore, stronger than the first, and more economical. The process of mar- bling, which is explained on page 324, is by pro- ducing veins of ferruginous matter, makes the mar- bled soap somewhat impurer. This soap is mostly used in medicine, for the manufacture of opodeldoc, suppositories and in pills, and in great demand for 320 SOAP MAKING. family use ; particularly the genuine soap, which is brought from Marseilles in small boxes and bars, weighing from three to four pounds each. It is much imitated in Paris an(f London, and instead of olive oil, tallow is mixed with it, which can be detected by analysis. Soft Soaps. The difference between potash and soda soaps con- sists in the difference of consistency ; the one is hard, and the latter soft, while the first is clearer and purer, the other is darker, smeary and much cheaper. Fish oils and red oils are mostly employed for soft soaps, therefore much cheaper. Saponification is commenced with a lye of 9 to 11° B., and the contents of the kettle kept boiling until the paste becomes of sufficient consistency to draw threads, as it were, out of a streak}^ substance. It then undergoes the process of clear boiling, for which pur- pose lye of 25° B. should be used. It must be stirred constantly; but when the paste does not sink any more, (first it ascends,) boils quietly and shows the formation of scales, it may be considered complete. The barrels should be immediately filled, in which it is to be offered to the trade. Hempseed oil is used in Prussia for soft soap, which is quite green ; but whale oil is principally employed. Many other oils, such as lin- seed oil, poppy oil, rapeseed, colza and cotton seed, are all used for a smear soap ; and in order to give the de- sired color of soft soap, various colors are added to it, such as indigo solution, with lime, &c. SILICA SOAPS. 321 Palm Oil Soaps. Palm oil is rarely used exclusively as a soap stock ; it is generally employed with rosin for obtaining a yellow soap. White soap from the bleached palm oil, combined with the cocoanut oil, is in great demand, say ten per cent, of the latter to ninety per cent, of palm oil, as with filled soaps. Tallow and palm oil, with a small quantity of rosin and cocoanut oil, pro- duce a fine and hard soap. The following receipts are known to the principal soap manufacturers : Palm oil. 300 lbs. Palm oil, 450 lbs. Tallow, 200 Cocoanut oil, 50 Rosin, 20 Hog’s lard, 550 ‘‘ Tallow, 500 Palm oil, 150 Palm oil. 300 Cocoanut oil, 50 Rosin, 200 “ Rosin, 50 “ Palm oil may be made into soap in the same manner as tallow, and if rosin is to be incorporated, it is best to produce first the combination of the rosin with the lye, and then mix the same with the finished palm oil soap. Palm soap becomes bleached when exposed to the light. The Silica Soaps. All soaps, whether hard or soft, and whetlier for domestic use or family soap, or for manufacturing purposes, bear safely an admixture of silicate of soda, 322 SOAP MAKING. to the extent of 20 to 25 per cent. (35° B.) to the ready prepared cold soap ; but it requires that the silicate be perfectly neutral, for if there is the least trace of fatty acid, silica will be precipitated, and the alkali will effloresce from the soap after a short time. Tlie dissolved silica, either the silicate of soda or potassa, of about 1.4 specific gravity, is gener- ally added while the soda soap is still hot, but is previously transferred from the cauldron into a tub or pan, called the mixing vessel, capable of containing about 1,400 weight of soap, and the silicate is to be added in such proportions as to yield the particular quality of soap desired to be produced ; the mixture is then well agitated by means of crutches or paddles. The soap and the viscous solution should each be at such a degree of heat, that the mixture, when formed, may be at a temperature of 160°, and the agitation is to be continued until the temperature is reduced 10°, or 150°. The mixture is then transferred to the cool- ing frames, and agitated therein by means of crutches, until it becomes of such consistence as to render its continuance no longer practicable. If a more rapid agitation could be applied, the soap produced is a more perfect mixture, and more uniform. The solu- tion of silicate of soda at 35° B. is well for an addi- tion to any soap. The curd or white soap, the yellow or rosin soap, the palm and olive soaps, may all be treated with the addition of 20 to 25 per cent, of soluble glass, standing from 25° to 35° B., and the^ manipulator will succeed in producing a good deter- gent soap, which will not crust after a short time if the following rule is observed : Do not add the soluble glass until after the saponi- SILICA SOAP. 323 fication is complete, and before the soap is cold. Use the silicate of soda hot, and as neutral as possible, and crutch it with the ready made soap in small portions, and do not use more than 20 to 25 per cent, of the silicate to the soap, and continue the operation of crutching for several hours. In order to be able to use the silicate of soda in a neutral state, for the com- mon soluble glass is more or less alkaline, it is best to add two pounds of hydrochloric acid to each twenty gallons of the soluble glass solution, standing 30° to 35° B., and while hot keep the acid agitating for an hour or so, when the same will become neutral and suitable to be mixed with the soap in the mixing vessel. The common silica soap in trade consists of 90 pounds salt, 15 “ cocoanut oil, 15 “ caustic lye, 50 “ silicate of soda. The soluble glass may as well be used in soft soaps in the same manner as described for hard soaps. The mixed silicated soaps may be obtained of any requisite degree of hardness, by the greater or less concentra- tion of the solution of soluble glass. The compound soaps produced by this process are possessed of valu- able detergent properties, independently of the real soap contained in them. Many varieties of soap are known in the trade under the name of silicated soaps. Silica, silex, sand and pumice soaps, even when the soap is mixed or adulterated with white china clay, talc, soapstone, and other materials ; those soaps are oflered under the name of silica. 324 : SOAP MAKING. In the preparation of sand soaps, the finely sifted sand or fiint is added to ordinary white soap, and thoroughly incorporated with it, while in the pasty condition, from eight to ten per cent., and as soon as the mass has cooled, it is taken from the frame and cut into tablets or molded into balls. Mottled or Marble Soap. In the manufacture of this variety of soap, the same kinds of materials are used as for white soap, and its difierent appearance arises from the different mode of treatment of the soap, after the completion of saponification. It has already been observed, that even after the complete formation of the soap, that is, when the whole of the oil or fat used is decomposed, and the oily acids have entered into combination with alkali, the soap still requires further treatment before it is brought to market; the immovable globules have to be brought into a homogeneous mass, which is effected by the process termed fitting, which consists in the fusion of the contents of the boiling cauldron in a weak lye or in water, and afterwards boiling the whole for a longer or shorter period, so as to break the froth and favor evaporation. During this process in making white or curd soap, the more or less colored impurities of the materials, termed nigger, fall to the bottom ; but in making mottled soap, the mixture is left in a thick or viscid state, so that the impurities cannot subside, and is transposed to the frames in this condition. To produce a good marbled soap, it is necessary that the latter operation be very carefully conducted. TOILET SOAPS. 325 for if too great a quantity of liquid be added, or if the mixture of soap and water or weak lye cools too slow- ly, all the coloring matter falls to the bottom, leaving the upper stratum of soap perfectly white, while, on the other hand, if it becomes too quickly cold, the soap remains in the granular condition. The lower veins in mottled soap appear to be due to the presence of exceedingly minute traces of sulphide of iron, derived from the last service of lye, in which it exists in solu- tion as a double sulphide of sodium and iron. At Marseilles and other places where olive oil is used in making soap, a quantity of sulphate of iron is added, whereby the mottling is produced ; about eighteen ounces of copperas to 450 pounds of oil, wdiich is added, first mixed with weak lye, are poured in during the coction of the soap, and before it has ac- quired too much consistence. When the soap is ladled out of the boiler, it is of a uniform slate tint, but as it becomes cool, the metallic portion separates into nodules, and by the trickling of the excess of lye through the mass, they assume those forms to which the term mottled is applied. According to the tint of the sulphate of iron, a lighter or darker hue appears on the surface of the soap. Toilet Soaps. The great variety of soaps thus designated are usu- ally prepared by remelting and clarifying white or curd soap, and adding various perfumes, colors, etc., all of which is more the province of the perfumer than of the soap maker. The most convenient method of preparing soaps for the toilet is by the cold process. The fullowing method is pursued : 15 326 SOAP MAKING. First, the fat is melted in a well cleaned iron or copper kettle at a low temperature ; it is filtered then through fine linen or muslin into another kettle, when it is boiled with one third of water for ten minutes, and then strained ofif Some add for 100 pounds of fat, six ounces salt and three ounces fine pulverized alum ; they let it remain quiet for some hours, until it becomes what is called figging. To the fat, which must not be warmer than 104® Fab., the Ije is gradually added. In the soaps made after the cold way^ a very strong lye is used, say 36° B., and for a certain quantity of fat just half is employed, say for eighty pounds fat, forty pounds of Ijm. The lye must be entirely clear and colorless, but it is not necessary that it be heated previously, when it has been kept in a warm room. For stirring it, a broad paddle of box-wood must be used, having sharp edges at the lower end, and rounded at its upper end, so that it may be easily handled. The necessary coloring matter and perfumery should be added as soon as a ring drawn with the spatula can be recog- nised. The paste is now run into frames previously lined with linen ; each frame should be entirely filled with the mass, and w^ell closed with the linen and wooden cover, and left then for twelve hours, by which time saponification will have been efiected ; the mass, which was nearly cold when run into the frames, has undergone a spontaneous reaction, raising the temperature over 175° Fah. The different con- stituent principles are now combined ; the soap pro- duced is of a quality resembling that of boiled soaps. After twelve hours the soap is taken out, and cut and dried ; and for making it a little softer one-tenth of TOILET SOAPS. 327 potash lye is added to the soda lye, for the purpose of increasing the solubility, and consequently the quality of the soap; for when no potassa is added, these soaps are generally hard ; 100 pounds of fat will yield about 150 pounds of soap. KURTEN’S TABLE, Showing the composition and yield of Soap Toy the Cold Process, from Concentrated Lye, and mixtures of Cocoa Oil with Palm Oil, Lard and Tallow. Emus OF Soap. Tallow. 1 Cocoanut Oil. Palm Oil. Lard. | ao 0> Si be 0 ^ P 1 Salt Water. Degrees. 1 Potash. 1 Degrees. Product. Cocoanut Oil, No. 1,. Paris Toilette, (round,) (( (( Windsor, (square,) Shaving', No. 1, 20 66 66 33 33 60 30 40 ( 100 30 25 34 34 or 34 34 40 or 1 40 1 60 or I 60 IlOO or 1 90 or 90 *8 75 56 31 50-52 77 36 36 36 30 5 13 36 30 153 87 150 185 Shaving, No. 2, Washing, No. 1, 33 33 120 27 i 214 120 27 12 12 226 Washing, No. 2, 30 125 27 25 12 244 Ordinary Cocoanut Oil, ... 40 135 27 50 15 278 i 101 ••1 10 ’225’ 21 75 12 400 The marbling of these soaps is produced by rubbing up the coloring material, snch as vermilion, smalts, or ultramarine, with a little olive oil or soap, a small por- tion of which being taken on a pallet knife, is pushed through the melted mass. Tlius the pink color of rose soap is produced by vennilion ; blue by means of ultramarine, and brown by the addition of the various 328 SOAP MAKING. kinds of ochres and umbers. Generally speaking, the colors are varied much, particularly since the aniline colors are so much used. The violet is obtained from fuchsine dissolved in glycerine; green color, the real chrome green is used ; chrome red is also employed for a red coloring, and caromel or sugar coloring for producing a good brown color. The lemon and orange yellow, with which we often find the German oval cakes of fancy or toilet soaps colored, is the sulphide of cadmium, known under the name of cadmium }^el- low, which is not dissolved in the soap, but merely suspended by very careful mixing, for it is rubbed up with oil, and added to the soap under constant stir- ring ; it requires but a very small quantity to produce a lively color, and neither sun nor age affect the color. The cakes or tablets are formed by placing a soft mass of soap in a mould fixed in a lever press ; the mould consists of a top and bottom die, fitting into a loose ring ; by a sudden pressure the shapeless mass assumes the form of the ring, and is embossed on the top and bottom. Naplks Soap. This highly esteemed shaving soap, always imported from Italy, is said to be produced by saponifying mut- ton suet with lime, and then separating the fatty acids from the soap so formed by means of a mineral acid. These fatty acids are afterwards combined with caustic potassa, by ebullition in the usual way. Transparent Soaps. They are prepared by dissolving well dried soaps in alcohol. Those made of olive oil will not become PERFUMING SOAPS. 320 transparent with alcohol, but become opaque. Good suet and rosin, and tallow soaps, are best suited for a transparent soap. Tlie mode of proceeding is to cut into very thin ribbons, by means of a cutting mill or knife, and left to dry in the air or sun for some time, until properly diw ; it is then pulverized, and then dissolved in strong boiling alcohol, say 80 per cent.; when the soap is liquid, the colors and perfumes are added to it. Three and a half gallons alcohol, of spec, grav. 0.849, is suitable for fifty pounds soap. A still heated by steam or hot water is generally used for this purpose, in order to save the alcohol, which will amount to five pints, will pass over from the employed three and a half gallons into the coolers of the still. The thick liquid in the still is turned out into moulds arranged for them, either balls or square moulds; but their capacity should be one-third larger than the size of the forms intended, thus allowing for the shrinking of the soap material. The soap becomes dry after a few days, and when of a dull appearance is turned off with a round knife, and a neat surface produced by rubbing it with a fine linen, saturated in alcohol. Perfuming Soaps. When the paste or soap is already in the frames, the process of perfuming is performed, and the same must be nearly cold, else the essential oils would be volatilized ; it is, therefore, best to mix the colors and perfumes together with some alcohol or glycerine, and stir them well up in the paste. In France, where the finest soaps are manufactured in the cold state, very highly perfumed soaps are prepared. Although the 330 SOAP MAKING. process is very simple, still, their mechanical in- genuity makes their soaps excelsior. Formulae for some well known soaps : Windsor Soap. 1. (White.) The best English Windsor soap is pro- duced from a mixture of 1 pound olive oil, 8 “ tallow, both saponified with caustic soda lye, and scented after the removal from the boiler. Curd soap, well scented, is sold generally for Windsor soap, being flavored while semi-liquid with oil caraway, and a very small quantity of oils of bergamot, lavender or origanum are added, say about one and a half pounds of the oils to everj^ hundred weight. 2. Brown AYindsor soap. It is the same as the white, only colored by caromel, and sometimes with umber or ochre. Honey Soap. The finest rosin soap, colored by palm oil, or palm oil soap, and scented with rose geranium and a little oil of bergamot or verbena. Some honey soap has the following composition : 1 pound olive oil soap, 1 “ palm oil soap, 3 white curd soap, colored by a little palm oil or annatto, and scented with various fine essential oils of one and a half pounds to every hundred weight. AXMOND SOAP. 331 Musk Soap. The base of this soap is a good suet or tallow soap, scented with tincture of musk and a little oils berga- mot, cinnamon and cloves, and colored by caromel. Ambergris soap is made in the same way as musk soap. Glycerine Soap. Any hard soap in which three or four per cent, of glycerine has been intimately incorporated while in the paste, will represent this soap. It is colored of a red or rose color, or orange-yellow; oil geranium and oil cassia, with a little essential oil of bitter almonds, are the favorite perfumes. Struve, of Leipsie, prepares a glycerine soap in the following manner.: 40 pounds tallow, 40 pounds lard, 20 pounds cocoaiint oil, are saponified with 45 pounds soda lye and five pounds potash lye, of 40° B., and the soap is to be made in the cold way. To the paste are then added: G pounds pure glycerine, i ounce oil bergamot, 1 “ Portugal, 5 ounces oil bitter almonds, 3 vitiver. Almond Soap. The bitter almond soap is made from the white curd soap, with or without the addition of 1-7 of its weight of olive oil soap, scented with the essential oil of almonds, or oil of mirbane, in the proportion of S32 SOAP MAKING. about one ounce to each five pounds ; a little oil cassia improves it. This toilet soap is the white curd soap, scented with orris root, and colored with litmus tincture ; also by melting 3 pounds white curd soap, 1 pound olive oil soap, 3 pounds palm oil soap ; and the whole scented Olive soap, 2|- pounds. White curd soap, pounds. Oil bergamot, 1 ounce. Oils cassia, cloves, sassafras and thyme, each 1-J drachms. Oil neroli, or English lavender, 1 drachm, Levigated brown ochre, 2 ounces. Another bouquet soap is made from 20 pounds curd soap, ounces oil bergamot. And oils cloves, neroli, sassafras and thyme, ^ drachm. And colored with 2-| ounces brown ochre. Violet Soap. with orris root. Bouquet Soap. Kose Soap. Palm oil soap in shavings. White curd soap Soft water, 3 pounds. 2 4 ounces. MILITARY SHAVING SOAP. 333 Melt in a bright copper pan and water-bath, and add J ounce of vermilion, or perfume with J ounce otto rose, 1-J- drachms oil bergamot, “ rose geranium, f “ of oils cinnamon and cloves. Another rose soap is made from 20 pounds curd soap and the variety of oils. Cinnamon Soap. It is a mixture of tallow and oil soap. Take 6 pounds white curd soap, 3J “ palm oil soap, 1 pound cocoanut oil, l-J ounces oil cinnamon, J ounce oils bergamot and sassafras, each, 1 drachm oil English lavender, J ‘‘ levigated ochre. Lavender Soap. It is Windsor soap scented with essential oil of lavender, and essence of musk and ambergris. Orange Flower Soap, Like rose soap, flavored with oil neroli, and ambergris, and Portugal. Military Shaving Soap. To the white olive oil soap is added the bayberry wax, and scented with oils caraway and cassia. 15* 834 80AJP MAKING. Cream Soap and Shaving Paste. These preparations are excellent for shaving are composed of White soft soap, Finest honey soap, Olive oil, Water, Carbonate soda, they 4 ounces. 2 ‘‘ 1 “ 2 tablespoonsful. 1 drachm. Melt them together and form a paste, adding a little ])roof spirit, and scent at will ; by adding about 1 drachm -spermaceti the paste becomes more soft ; it makes a lather with cold water. Cream Pearl Soap. Take lard potash soap, or white soft soap, rub it up in a marble mortar, so as to become a uniform mass, or pearly, and scent it with oil almonds and cassia. Shaving Essence. Take white hard soap, J pound, “ pure spirits, 1 pint, ‘‘ water, 4 ounces, and perfume at will. Let the mixture stand in a water-bath for a few days, occasionally agitating it, until it is completely dissolved ; draw off the clear liquid, and perfume it to suit. The Commercial Value of Soaps. Since we distinguish soft soaps (potash soaps) from hard soaps, (soda soaps,) and filled soaps from grain soaps, it is necessary to ascertain the intrinsic value of any soap, according to its purity. In the first COMMERCIAL VALUE OF SOAPS. 335 place, we recognise two main varieties, or groups : first, the rosin soaps, and second, the fat or oil soaps. Among the latter are the more important, such as tallow soaps, palm oil, cocoanut and olive oil soaps. In addition to these, however, there are many mixtures of fatty substances in combination with alkalies, known as soaps. In good soaps there is a definite proportion between the water, the alkaline 'base, and the fatty acids ; there should be no excess, either of the base or of the constituents of the fat, at the same time it must be free from salt or an excess of water, which is but an adulteration, like other substances known to be mixed into soaps, like sal soda, alum, salt, bone ash, glauber salt, or clay. A good soap is easily soluble in alcohol, scarcely leaving one per cent, of solid resi- due, and forms a gelatinous liquid in boiling water. A hard soap should not contain more than 25 per cent, of water, of rosin not more than 40 per cent., and A)f soft soap, not more than 52 per cent. For cocoanut oil soaps, a larger amount of water than 52 per cent, may be allowed. In the yellow soap, a part of the fat is replaced correctly by 10 to 15 per cent, of rosin. All these proportions are reliable, and if increased or replaced by other substances, the quality of the soap is diminished, although some soap makers think that an excess of alkali is quite justifiable, in order to make the soap more soluble ; they do not con- sider that the various salts contained in many waters form insoluble compounds with the fatty acids of the soap, while an excess of some sal soda would be more advantageous. The composition of the different kinds of soap, by various manufacturers, are given in the following tables : HARD SOAPS. 336 SOAP MAKING tH ^ tH 05 . i>; ,05 , , rij i> 00 , 05 W (M, , . '^'ooooOTHrHoiio c6-riH05odcoooT-4iooo Oi 1-i Oi a CO lO no lO T-l (M CO O , <0i . CQ 1C O? i>£>ici>05idido5 O? 1C 00 Oi GO CO CO 05 •UTS ■oa pat? ! , , . ci , 1C ' IC 'TjH CD cd 03 ' J> CO CO 1C CO CO CO •sppvA^M 1C CO 1—1 C<* THcdoici>o6cdo'^ic OOi>lC'^COCDCOlCCDi> o m m v» a § f > 'O ^ p. o o fl "o p 02 gl^ g® C ;h c3 0) += o bb <1 W oo CO cd w JO tH 05 CO CO 'sJH £- •QTipiSgj 9tqnpsat puB amini (•TO "BSSB^OJ jfjQ •Bpos ^ja , lO 05 . »o .. i> cd cd i> CD TfH *UIS -OJI puB :;bj • o • • • • . t- • . . . •spiov «d • O cd 05 05 i> • O lO to C5 Name. Poppy Oil Soap, Glasgow Brown Resin Soap, Glasgow White Soap, Manchester Palm Oil Soap, London Curd Soap, London Marine Soap, 338 SOAP MAKINO. To Determine the Amount of Water op a Com- mercial Soap. Take 80 grains of the respective soaps, and put them in a water-bath, and add a saturated solution of nitre, and heat both to the boiling point ; keep boiling for two to three hours, and add more water, if some should be evaporated during the boiling ; note the weight, and keep for two hours more heated ; if not diminished after that time, it proves that all the water is expelled. If the original weight of the soap was 80 grains, and after drying was but 67 grains, it would make it equal to 16J per cent. To Determine the Amount^ of Fat. By decomposing the soap by an acid, the fat is easily found. By putting 80 grains in a porcelain dish, and adding 20 to 30 times as much in weight of oil of vitriol, diluted 12 times with water, and heating the whole over a lamp, until the fat is floating on the top. If 60 grains remain, deduct for tallow, which is equal to 88.05 grains, and 80 grains soap would contain 72.8 per cent. Rosin is detected by ascertaining the weight left undissolved after the alcohol has taken up all the fat, which is, however, a very uncertain test. Other pro- cesses have been proposed, by means of strong hydro- chloric acid, which appears to be more reliable. Free alkali may be easily ascertained if it exists in soap. The following substances are used for Ailing up the FILLING UP THE SOAP. 339 soap, some of wJiich may be advantageously employed, and some serve as adulterations : Gboup I. Group II. Group III. Water. Earthy Matters and Salts, Organic Matters. Soluble and Insoluble in Water. Soluble and Insolu- ble in Water. Soluble. Chloride of Sodium. Soda. Glauber Salt. Borax. Soluble Glass. Carbonate of Ammonia Alum. Acetate of Lead. Insoluble. Soluble in Hydrochlo- ric Acid, MAGNESfA. LIME. CHALK. BONE ASHES. PIPE CLAY. Soluble. Sugar. Starch. t Dextrin. Glue. Insoluble. Free Rosin. Free Fat. ' Hot Soluble in Hydro- chloric Acid. SULPHATE OP BA- RYTES. SAND.* The object of the introduction of soluble glass in the manufacture of soap, or as a substitute, if economy is at stake, may be exemplified by the following remarks : The treatment of lyes alone, with wool or silk, prove the superiority of the soluble glass, as it removes but externally the adhering dirt, wdthout any injurious effect. The slippery and adhesive consistency of solu- ble glass act likewise beneficial in the easy w^ashings, and rinsings with much water the adhering impurities. There are many advantages in its applications on * An admixture of sand cannot be regarded as fraud, if the soap is sold as sand soap. f We do not know if starch has any cleansing qualities ; it is so stated in a report on the different uses of the potato, published in 1827 by the two French chemists, Payen and Chevalier, but we doubt it. 340 SOAP MAKING. wool, silk, cotton and leather ; it is stronger than com- mon soap, requires a less quantity, and either hard, soft, cold or lukewarm w^ater may be employed. The labor and saving of fuel is an advantageous economy ; it preserves also many colors, which are not fast, much better than common soap ; it resists, in fact, almost all colors. From one to four pounds liquid glass is sufficient for 100 pounds of water. As that used for wool is quite sufficient for a menstruum, it is employed quite extensively in Europe for wash- ing and fulling of wool, and it has been used long before the soluble glass was known, by dissolving flints in caustic lye prepared from wood ashes. The Prussian Government has found it advisable for the introduction of the soluble glass in the military and other royal institutions and prisons, and also for the paper manufacturers, and their extensive linen establishments ; and instituted experiments as to the practicability of a general economical application. In the cotton mills it has proved a saving of fifty per cent, by substituting it for starch and flour, which was so indispensable for fastening the colors; and in England, thousands of pounds sterling have been economized by its application. In our late war the consumption of the soluble glass in that branch of industry of the United States was very extensive. The soap manufacturer, who formerlj^ did use rosin for an adulteration or admixtui'e, the cost of which was formerly but two dollars, but rose to twenty-five and thirty dollars per barrel of 180 pounds, was obliged to resort to the use of soluble glass in its various forms, either as liquid or jelly. Posin is now again more employed than the soluble CETOLITE SOAP. 341 glass ; not, however, for the reason that it is better as a sophisticator, but because the soap maker has an idea 4hat the soap formed from rosin with fat suited better, and is more time saving. He does not consider all the circumstances ; such as the smell and touch produced in the handling or washing with rosin soap, and that the admixture of soluble glass is no adultera- tion, but an improvement, and that it is as economical as rosin soap. The Cryolite Soap, which was introduced in the market, is a rosin soap, to which the powdered cryolite is added by crutching, or it is added right after the saponification has taken place, before it is taken out from the kettle. The writer has seen such a soap, which was quite soft, and could not be made hard, except by adding some adujteration, such as clay or talc, if it is intended to be a saleable soap. I isrj) E X PAGE Action of Acids, 278 Action cf Alkalies, 278 Action of Hydrofluoric Acid,.. 278 Adhesive Lubricator, 164 Albumen liable to decomposi- tion, 131 Alkaline Sidts from Hydraulic Lime, 112 Alkalies in the Soluble Glass,. 36 Alkalies— Soap, • 292 Almond Soap, 331 Alumina, an undesirable ingre- dient in Glass, 216 American Hydraulic Mortar. . . 96 Amorphous Glass, 281 Amulets, Glass, 284 Analysis of Sap, 136 Ancient Mortars, 100 Animal Fats, 305 Annexing of Pots,..* 213 Annealing Oven 209 Apothecaries’ Vials, 234 Apparatus in Soap Making,.. . . 291 Application of Soluble Glass in Brooklyn Navy Yard, 15 Aquamarine and Garnet, 269 Aquarium Cement, 165 Areometric degree of Lye, 298 Arsenic, 36 Arsenic promotes decomposi- tion, 217 Artificial Grindstones, 196 Artificial Meerschaum, 60 Artificial Stone, general ideas on,.’ 94 Artificial Stone, report on, 178 Art of Manufacturing Glass,. . . 290 Astronomy through 'Glass, 282 Avanturin Glass, 273 Barrel Protection, 163 Baryta and Zinc Paint, 115 Baryia used in Glass, 216 Beef Tallow, 305 Beton Coiguet, 150 PAGE Beton’s Crushing Weight, 186 Beton’s Keport, 181 Bible refers to Glass, 283 Black Ash, 293 Blanc Fix Manufacture, 123 Blowing of Glass 283 Bohemian Crystal, 235 Bone Ashes, 217 Bone Fat, 306 Boracic Acid, 312 Borax and Boracic Acid, 217 Bouilly’s Cements, 76 Bouquet Soap, 332 Brown and Miller Pavement,. . 153 Brown Windsor Soap 330 Butter, its melting point, 3u6 CarbolicAcid precipitates Silica, 127 Carbonate of Soda, 294 Castile Soap, 319 Cast Iron Kettles, 291 Causes of Hardening of Glass, . 109 Cements, Lecture on, 71 Cement of Manganese, &c.,.. , 121 Chalk converted in Silica 113 Cheapest White and Yellow Glass 165 Chemical Properties of Glass,.. 277 Chinese Water Proof, 177 Chloride Calcium, 17, 193 Cinnamon Soap, 333 Circular on Uses of Soluble Glass, 47 Cistern Cement, 171 Cistern Lining 105 Cocoauut Oil, 301 Cocoanut Oil Soap, 318 Colored Cements, 173 Comforts of Glass, 282 Commercial Value of Soap, 334 Common Flint Glass, 254 Common Mortar, 77 Component Pots, 265 Composition of Glass,. .206, 212, 288 Consumption of Coal, 203 344 INDEX. PAGE Contents of Pots, 256 Cracks in Stone, 170 Cream Pearl Soap, 334 Cream Soap and Shaving Paste, 334 Creosote on Woody Fibre, 127 Crown and Plate Glass Fur- nace, 209 Crown Glass, 236 Crucibles or Pots, 211 Cryolite Glass, 276 Cryolite Soap, 341 Crystal Glass, 252 Gullet Waste Glass, 218 Damp Cellars, 81 Date of Glass Making 283 Decay of Wood,, 130 De-Coloring Materials, 218 Definition of Glass, 283 De Milly Process, 311 Deville’s Remarks, 70 Discovery of Glass, 282 Doebereiner’s Method, 15 Double Soluble Glass 39 Drain and Gas Pipe Cement,. . 170 Easel Painting, 122 Effect of Acids on Glass, 277 Effect of Air on Glass, 277 Effect of Water on Glass, 277 Elaidic Acid, 307 Elastic Glass, * 281 Electric Soap, 316 English Bottle Glass, 228 English Crown Glass., 238 Eremacausis, 131 Etching on Glass, 259 Extent of Infusorial Deposits,. 19 Family Soap manufacture, 315 Faraday’s Glass, 263 Faults in Glass, 224 Felspar a good body, 217 Felspar as constituent, 220 Figging Soap, 326 Filling Materials in Soap, 339 Filling of Soap, 293 Finingof Glass, 223 Fire and Water Proof Cement, 94 Fire Clay, 211 Fish Oil, 306 Fiske Concrete Pavement, 155 Flashing and Casing, 271 Flint Glass, 252 Flint Glass Furnace, 207 Fluorspar, 36 Fluorspar much in use, 217 PAGE Fluxes, 275 Formula for Silica Soap, 323 Formula for Tallow Soap, 318 Fremy’s Remarks on Cement, . . 68 Ph ench Bottle Glass, 229 French Flint Glass, 256 PTencli Plate Gla'S, 242 Fuel in Glass Making, 221 Furnaces, duration of, 208 Gas Pipe Cement, 172 General Protection, 162 General Remarks on Soluble Glass 199 General Rules for Wood Pave- ment,' 159 German Hydraulic Cement,... 100 Glass Harmonicon,, 282 Glass Makers’ Soap, 219 Glass Making Art, 205 Glass Materials, 214 Glass Mosaic, 272 Glass Painting, 273 Glazing and Enameling, 167 Glory Hole, HO Glue Substitute, 167 Glycerine, 289 Glycerine Soap, ; 331 Granite Pavement, 153 Grape Vine Manure, 166 Gravel Cement, 172 Green Bottle Glass, 228 Green Sand, 200 Green Sand a substitute for Sand, 217 Grinding and Polishing Glass, . 246 Guinaud’s Plan, 263 Gypsum Cement, 170 Hard and Soft Soaps,, 289 Hardening Mortar, 277 Hardening Process of Cement, 98 Hard Soaps, 315 Herculaneum Glass, 284 History of Roman Cement, .... 109 Hock Wine Bottles, 231 Hogs’ Lard, 306 Honey Soap, 330 Horse Fat, 306 Hubert’s Apparatus, 292 Hydraulic Lime, 62 Hydrofluoric Acid, 260 HydrofluoricAcid hardens Gyp- sum ^ 120 Hydrofluoric Acid hardens the Lime, H9 INDEX. 345 PAGE Hydrofluoric Acid heightens the colors, 113 Imperfect Conduction of Glass, 279 Impregnation of Wood by pres- sure, 132 Impurities of Palm Oil., 302 Iron an unwelcome element in Glass, 217 Iron Block Pavement, 154 Iron Cements, 75, 171 Iron Ship Bottoms preserved,. 164 PAGE Mottled Soap,. 324 Musk Soap, 331 Mutton Suet, 305 Naples Soap, 328 Nature of Limestones, 65 New Soap, 316 Nicholson Pavement, 146 Nicholson’s Process, 156 Nigger, 315 Nitrate of Soda, 36 Nitrate of Soda Formation, .... Ill Kaulbach’s Soluble Glass, 40 Kneading of Glass, 211 Krieg’s Carbolic Application,.. 127 Kuhirnann’s Process, 17 Kyanizing, 129 Lard Oil, 306 Lavender Soap, 333 Lead, the ingredient in Crystal Glass, 216 Le Blane’s Discovery, 215 Lemon Yellow Soap, 333 Liebig’s Infusorial Process, .... 39 Liebig’s Method, 16 Lime the constituent of Glass, . 216 Lime and organic substances treated,, 125 Looking-Glass Tarnish, 278 Lumber Drying 140 Lye, its meaning, 296 Manganese and Zinc Cement,. . 101 Manufacture of Soluble Glass,. 13 Margaric Acid, , 288 Marseilles Experiments with Beton, 187 Marseilles Soap Manufacture,. . 290 McCully & Co., Green Glass Manufacturers, 286 McGonegal Pavement, 157 Melting of Materials, 222 Merits of Wooden Pavements,. 149 Metallic Cement, 176 Method of Preserving Wood, . . 141 Microscope through Glass, 282 Military Shaving Soap, 333 Mixing Apparatus, 221 Mode and Mechanical Opera- tion, 257 Mode of Application of Wood Pavement, 126 Mofurra Tallow, 304 Mortar, 62 Mortar Composition, 77 Oil Mirbane, 317 Oil of Poppy, 304 Oleic Acid, 288,307 Olive Oil, 304 Optical Glass, 261 Orange Flower Soap, 333 Origin of Glass, 18 Outside Wall Cement, 174 Painting on Metals, 121 Painting on Stone, 116 Painting on Wood, 119 Palmitin 300 Palm Oil, 301 Palm Oil Bleaching, 304 Palm Oil Soaps, 321 Parisian System of Pavements, 147 Payen’s Kecommendation, .... 132 Pearl Ash, 36 Peasley Cement, 171 Pennsylvania Glass Manufacto- ries, 285 Per Centage of Phenic Acid in Coals, 142 Perfuming of Soaps, 329 Permanent White, 123 Peroxide of Manganese in Glass, 219 Petitjean’s Method, 250 Phenic Acid, the Preservative, . 142 Physical Characters of Glass,. . 279 Piers and Breakwater Beton,. . 187 Pittsburgh Glass Manufacture, 286 Plate Glass, 241 Pliny’s Remarks, 139 Portland Cement Analysis, 71 Portland Cement Capacity, .... 71 Portland Cement Manufacture,. 83 Portland Cement Production. . 84 Portland Cement Tensile Strength, 87 Portland Vase, 283 Potash Soluble Glass, 37 Potassa and Soda, 292 INDEX. 846 PAGE Preserration of Old Monu- ments, 95 Preservation of Wood, 129 Preserving Walls, 161 Properties of Palm Oil, Sol Quartz, its characters,. 23 Quartz, its forms, 22 Quartz, its Mineralogical Cha- racters, 26 Quartz, its Varieties, 23 Eail-Road Sleepers, 126 Eansome’s Method, 50 Eansome’s Stone Eeport, 189 Eeaumur’s Glass 207 Eed Ink from Silica, 122 Eed Oil Soap, 308 Eesistance to Water and Ileat,. lOl Eoadway Pavements, 152 Eobbins’ Pavement 158 Eobbins’ Pretended Discovery, 144 Eoberts’ latest Preservative,... l74 Eoman Cement, 72 Eondout Cement Analysis, 73 Eoofing Shingles, 126 Eoof Shingles Preservative,.. . 145 Eosedale Eiver Cement, 97 Eose Soap, 332 Eosin Detection, 338 Eupert’s Drops, 280 Sal Soda, 293 Saltpetre Formation, 110 Saltpetre Percentage, Ill Sandiver or Glass Gall, 223 Sapphire and Amethyst, 269 Seeley's Concrete, 159 Setting of Pots, 213 Shaving Essence 334 Ship an I other Timber, 126 Siemen’s Apparatus, 42 Siemen’s Directions, 45 Silica, ; 21 Silica Soaps, 321 Silicification of Chalk, 53 Silicification of Organic and In- organic Substances, 113 Silicification of Wood, 124 Silicium, 20 Silvering Fluid for Glass, 249 Smalt, 219 Soap Making, 288 Soda, 36 Soda Soluble Glass, 38 Soda Water and Champaign Bottles, 230 1>A0B Soft Soaps, 320 Soluble Glass, 13, 276 Soluble Glass fi>r Silk 340 Soluble Glass lor Wool, 340 Soluble Glass in Prussia, 340 Soluble Glass, its various appli- cations, 60 Soluble Glass Soap, 322 Sources of Sand, 215 Sorel’s Cement, 107 Specific Gravity of Glass, 287 Sperm Oil, 3u7 Squaring Glass, 247 Stafford Pavement, 146 Stafford’s Process, 159 Steam Eesisting Cement, 169 Stearic Acid., 288 Stereochromic Painting, 116 Stillingia Butters, 304 Stone Cement, 173 Stone Pavement, 157 Strass and Colored Glass, 264 Street Pavements, 145 Strength of Alkali, 294 Strength of Lye, 297 Struve’s Glycerine Soap, 331 Sulphate of Soda, 36 Sulphuric Acid Saponification, 313 Superheated Steam, 291 Superstition of Glass 184 Sweetening Cistern Water, 171 Table for Lyes, 297 Tables of Amount of Water in newly filled Woods, 139 Tablet Soaps, 328 Tallow Chandler, 290 Tallow Soaps, 326 Tail’s Cement, 166 Test for Soaps, 338 The Battledore, 225 The Cold Covering, 224 The Division of Glass, 226 The Frit, 221 The Glass House, 207 The Glass Maker’s Chair, 225 The Hot Covering, 224 The latest Classification, 227 The Marver, 225 The most Eefractory Cement,. . 177 The Pontel or Pontj', 225 The Pucellas, 215 The Shears, 225 The Springtool, 225 Timber Kot, 135 Toilet Soaps, 325 Topaz, Euby and Emerald, .... 268 INDEX. 84:7 PAGE Transparent Balls, 329 Transparent Cakes, 629 Transparent Soap, 828 United States Glass, 285 Varieties of Glass, 13 Varieties of Soluble Glass,. .... 14 Various Cements, 168 Vegetable Fats, 301 Venetian Filagree, 272 Venetian Skill...... 284 Vicat’s Keniarks, 117 Victoria Stone, 176 Violet Soap, 332 "Wagner’s Eemarks on Soluble Glass, 55 Wagner’s Varieties of Soluble Glass, 55 PAGE Wall Damp 'Cement, 79 Weight of Lye, 299 White Ash, 293 White Bottle Glass, 233 White Windsor Soap, 330 William Frice, the Glass Paint- er, 285 Window Glass, 236 Windsor Soap, 330 Wooden Blocks, 126 Wooden Roof Shingles, . ..... 128 Working Tools in Glass House, 225 Yellow, Blue and Green Glass, 267 Zeolites, Natural Silicates, 112 Zinc Cement, 169 Zinc Glass, 263 / Date Due ‘c.v V ' »r ' ri i: .y L. B. CAT. NO. 1137 F43 6 - ^ b~ & 4^ . LL_- f. /) ^ ^ ^ /- y j" j" GETTY CENTER LIBRARY