T.rai:Aa.^j:sE' HE OS HATE 81J.IOATE3, &C: E11C11TWAKG3UL Jitc A PRACTICAL TREATISE ON SOLUBLE OR WATER GLASS, SILICATES OF SODA AND POTASH, FOR SILICIFYING STONES, MORTAR, CONCRETE, AND HYDRAULIC LIME, RENDERING WOOD AND TIMBER FIRE and DRY ROT PROOF, &c., &c., &c. WITH HOMMtKDSor RKCEIPTS for SOAP, CKMEMS, PAINTS & WHITEWASHES, R. B. SLEEPERS, WOODEN PAVEMENTS, SHINGLES, Ac. ItY DR. LEWIS FEUCHTWANGER, Chemist and Mineralogist. Concluded with Various Essays on the Origin and Functions of Carbonic Acid, Limestones, Alkalies and Silica ; and a Complete Guide for Manufacturing Plain and Colored Glass. •WITH S E V E 12. -A. Hi W O O X) C TJ T S . NEW YORK. Published by L. & .1. W. Feuchtwanger, 55 Cedar Street. 1870. Entered according- to act of Congress, in tlie year 1870, By Dr. Lewis Feuchtwanger, In the Clerk's Office of the District Court of the United States for the Southern District of New York. ItOBBRT Maloolm, Pkintbk, 49 Cedar Strbet, N. Y. P R E; K C E . ,4-^ The object of this Trcatisi' o!i Soluble or Water (xlass is to give some inforinntior) • to the inaiiy iri(juiries, which liave been directed to the Antlior for some years past, m what manner and purpose this valuable j)reparation, so hij^hly recommended by the various scientitic journals, can be usefully employed. There is, as yet, no book published, treating on all its applications, with the exception of a pamphlet in French l)y Kuhlman hi 1859, containing mostly memoirs to the French Academy and the application of the water glass by calico printers and cotton manufacturers. It is for this reason that the Author felt the necessity of com- piling, all that is scattered, about the various uses of the solu- ble glass, in all the journals and Patent-OfKce reports. Not a day passes without receiving orders for samples, either in dry liquid or jelly state, with particular requests for explicit direc- tions ; nor does a day pass without being importuned by strangers and curious people, all desirous for information hoM* the soluble glass would answer for many purposes in domes- I iv. TREFACE. tic economy. The soap-makev, 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 fire-proof paint, for a hoop-skirt or shirt-collar, for a mucilage, a fire and water proof cement, and for many hun- dred other uses the inquiries are made ; and thousands of samples have, for the last ten years, been distributed to the inquisitive and speculative applicants. 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 y)atents issued in Europe and the United States, he has col- lected all information, along with that obtained from the scientific and practical journals, and experimenters will find in this Treatise the various uses and applications. Kuhlman's Pamphlet, the Mining and Engineering Journal, the Trans- actions of the American Institute, the Manufacturer and Builder, Scientific American, the Annual of Scientific Dis- covery, have all furnished material for this Treatise. Many inteiesting topics, such as the origin of the saltpetre and 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 formation of hydraulic cements and artificial stone, for the reason thjit more inquiries and experiments are performed in this branch than in any other of domestic economy ; the natural stones, PREFACE. such as the brownstorie, sandstone, limestone and brick build- ing, 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 impregnating the bricks, much is gained for their pre- servation. The editor of the Scientific American states, in a late article, that "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 increas- ing 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 demonstrate practically its capacity to fulfill the requirements of the case." He states further : " We have, for the last two years, availed ourselves of every opportunity aftbrded us to examine and test speci- mens of artificial stone, and 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 R. R. sleepers, wooden rails and blocks for pavement is in importance next to the preparation 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 prac- tice. The advantages of the wooden block pavement over all other kinds such as Macadamizing, gravelling, cinders, boulders and stone blocks are numerous, and if properly laid vi. PREFACE. 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 lias devoted so much space, upon hydraulic limes, mortars, paints, whitewashes and the preparation for guarding timber against dry rot and confla- gration is solely to prove and make it plausible that the application of soluble glass possesses great advantages, and may, with very little expense, give additional safeguards. The receipts and directions for preparing an innnense number of the most useful vehicles, cements for buildings and sidewalks, paints, varnishes, &c., cannot but be very acceptable. At the close of the treatise the author added several essays which refer to the main subject, such as that on car- bon and carbonic acid, in order to explain the wonderful properties of the latter, the eff"ect the same has in the appli- cation of the carbonic acid gas to hydraulic lime, and to the construction of buildings. The other, on limestone, is proved for the purpose of thr3wing some light, in a philosophical point of view, on the sources and functions of this all pervad- ing natural substance. The essay on the alkalies potash and soda was written merely to show the sources from where they are derived. The article on sand or silica is partially taken from the transactions of the polytechnical branch of the American Institute, before whom the author delivered a lecture on this: PREFACE. vii. subject, and he has added as a guide for the glass manufac- turer all the details for producing plain and colored glass, and an extract of an article on the green sand of New Jersey, by Joseph B. Lyman, on account of the peculiar properties of that substance, which may at some future day be employed in the production of silicates. The manufacturers of glass will find this treatise a useful guide. CONTENTS OF THIS TREATISE. Preface, Pages 1 to 12 Preparation by Fuchs, 14 " Doebcreiner, 15 Application at the Brooklyn Navy Yard, 19 " " Houses of Parliament, 18 Liebig's Proposition of the Infusorial Karth, 90 Silica and Quartz Synonymous, 88 Physical Description of the Whole Family, 26 The Use of Allialies, Salt Cake, Fluorspar and Arsenic, 40 Manufacture of the Various Kinds of Soluble Glass, 44 Plate of the Apparatus, Description of Siemen's Apparatus, and Directions 48 The Circular for the Uses of Soluble Glass, 52 Chloride of Calcium Gives the Indurating Action 54 Ransome's Ex[)crimcnts with Sili' cous Stone, •'•5 Author's Artificial Stone, 66 Great Improvement by Hydrofluoric Acid, f 57 Silification of Chalk, 68 Hydraulic Limestone and Mortar, 60 The Different Kinds of Lime, 64 Portland Cement, Iloman Cement, 65 Plaster Cement and Keene's Cement, 66 Hydraulic Lime from the Puzzuolanas, 67 Premy and Vicate Tlicoiies of Hydranlicity, 68 Deville's and liallard's Application of Matrmsia, 71 Author's Discourse on Cements before the Polytechnic Association,. . 78 Hydraulic Cement from Uondout, N. Y., 75 Kuhlman's Patent Lime Cemont 78 Bouilly's French Cement from Pebbles, 79 Common Mortar and Hydraulic Cement, 80 The Prevention of Wall-Damp, 81 Another Mode of Application to Damp Walls and Cellarb, 85 Fleury's liemaiks on the Alkaline Silicates, 87 American Limestone as Hydraulic Mortar, 90 The Theoretical Causes of the Hardening Process, 92 German Hydraulic Cement, 94 Ancient Mortars, 97 Solidifying I'roperty Depends upon Clay, 108 Oertlej^'s Silica Stone, Ill X. CONTENTS. iSilicification Process, Page lia Eemarkable Reaction of Hardening Porous Bodies, 118 Formation of Saltpeter and Nitrate of Soda Explained, 126 Silicification of Sandstone, White Lead, Chrome, &c., 124 Silicate Painting on Stone, 126 Stereochronaic Painting, 12T Application of Hydrofluoric Acid as a Fluo-Silicated Lime, 131 Stereochrouiic Painting for the Easel, 137 Pernaanent White, or Artificial Sulphate Baryta, 188 Preparation of Blanc Fix, 189 Silicification of Wood, 140 The Construction of the Munich Theater, 141 Full Directions by the Author 143 Letheby's liemarks on Dead Oil, 147 Violittier's " " Desication of Wood, 148 Wooden Roof Shingles and Farm Houses, 149 Preservation of Wood by Immersion, 151 Champty and Payen, 152 Popular Method of Guarding against Decay, 155 Methods Pursued by the British Navy, 156 The French Method of Preservation, 157 Wooden Railway and Wood Paving, 158 Prosser''s System Explained, 162 Timber Rot and Seasoning, 163 Resiuiferous Timber Most Durable, 167 Robbins' Process for Preserving Wood, 171 His Discovery of One of the Lost Arts of the Egyptians a Fallacy, 172 Patent of 1865 Anticip'!ited by Moll in 1835, 175 Recommended by Dr. Krieg in 1858, ,. 176 The Simplest Application for Wooden Roof Shingles, 176 Street Pavements Compared, 180 Broadway Pavement do 200 Fisk Concrete Pavement, 200 Hicolson 201 McGonegal " 202 Stowe " 203 Brown & Miller " 204 Bobbin s " 204 Stafford " 204 Seeley's Concrete " 205 Wooden versus Stone Pavement, 205 Mode of Application of Wooden Pavement, 206 How to Apply the Soluble Glass, 207 How Many Square Feet of Wall Covering, 208 What Dilution, 209 Preservation of Brick Walls, 209 Protection of All Wooden Utensils against Fire, Dry Rot and Leakage, 210 Silica Cement for Bottoms of Iron Ships, 212 Most Adhesive Insoluble ("ement, 212 Cheapest and Best Whitewash for In and Out Door Work, Fences, Ac, 213 CONTENTS. xi. Aquarium Oeraent, Page 215: Water-Tank Lining, 214 Tall'8 System of Concrete 214 Concrete liridge in London, it! Soap Substitute of Soluble Glass 219^ Okie Substitute, 221 Mucilage the Trade Mark of Solution, 221 Enamellinjf of Culinary Vessels. 222 Porcelain, Glass and Metal Cement, ^22 Milk Cement 22:T Marble 22? Zinc " 224 Foundation Wall Cement 224 Gypsum " 224 Hard Adbfsive " 225 Drain Pipe llesistintr a Pressure of 600 lbs. to the IlcIi 225 8tove Cracks (!ement, 226 Cistern 22ff The Most Refractf)ry Ceiiieni, 227 Beton Coignet Buildinfr, 22iS— 236 Essays Rclatintr to this Treatise 286 The Latest Tables of Klements 239 On Carbonic Acid, 23()— 273 On Limestones 978 Their Origin, 278 Their Preponderance in the Newer P'ormations 274 How to Estimate the Relations of Finite Powers of Man and the Attri- butes of an Infinite Being, 276 Limo is the Medium between Organic Beings and the Inorganir Progress, 276 Lime is the Oxide Calcium, which is One of the Nine Klements ci Constituents of Itocks, ^77 Lyell's Opposition to the General Opinion 278 The Origin either from Deposition or (-hemical Precipitation 2T8 Human Skeletons in the British and Paris Museums 279 The Coral Reefs Constructed by Polypiferous Zoophytes 280 Their Operations Described by Capt. Kotzebue, 281 They are 2,000 feet Thick, and Required 190,000 years for their Con- struction, 282 The Tropics the Hot-Bed for their Formation 282 The Principal Kinds of Coral Rock 283 The Reef- Building Coral, as Described in Hirsch's New Journal, The Arts, 286 The Other Organic Materials Forming Limestone Rocks, 28ff The Uncrystallino and Crystalline Limestone Rocks, 290 All Other Varieties of Limestone 291 The Hot Springs of Arkansas, 292 The Travertin Formations, 293 The Chalk Formation, 297 The Cretaceous Marl of New Jersey, 299 xii. CONTENTS. The Division of the Cretaceous Period. Page 300 Metamorphic Kocks Explained, ; . . . . 801 New York Island's (xeolog-y, 3OI Eight Rocks Compose the Island, 301 Dr. Stevens' Ideas Regarding the Island, 3O8 The Prevalence of Limestones on the Island, 303 They Form the Sedimentary Material, 304 The Aqueous, Volcanic, Plutonic and Metamorphic Division of Early Days 305 The Present Division in Stratified, Unstratified and Vein Condition, . . 305 The Division in Ages, such as Azoic, Silurian, Devonian, Carboniferous, Reptilian, Mammalian Age, and that of Man, 306 Another Division of tlie Geological Time, such as Azoic, Pa'.Tozoic. Mesozoic, Cenozoic, and Era of Mind, 307 Lyell's Division of the Tertiary Period, as Eocene, Miocene and Plio- cene Periods, 308 The Wealden Period is 150,000 Years Old, 30» The Origin of the Alkalies, Potassium and Sodium, and Application in the Soluble Glass, &c., The Manufacture of Soda Ash Detailed, 314 Silica, or Sand, Fully ExpUined, 316 Description of the Greensand of New Jersey, 318 The Physical and Chemical Cliaracters of Quartz, 324 The Many Varieties of Quartz Miueralogically Described, 326 History of Glass Making 328 Materials of Glass, 32» The Various Divisions in the Kinds of Glass in the London Exhibition of 1851, 332 The Present Classification according to the Constituents. 33S The Composition of All the Varieties of Glass, 340 The Artificial Gems, 341 Ideas on the Uses of Glass, 342 SOLUBLE GLASS, Alrio caller] 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 mixture of these tw^o 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 tliereby a flint 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 con- tain less alkali and some oxide of iron and alumina (cl-ay), are more dithcult o^ fusion than other kinds. The soluble glass was brought to practical uses by Professor Fuchs, of Munich in Bavaria, in the year 1823, by igniting strongly in a refractory furnace or crucible for six hours, a mixture of 10 parts of pearl ashes, 15 parts of powdered quartz, or line sand, and 1 part charcoal ; tlie mass was then pulverized and 14 SOLT^BLE GLASS. added in small portions to boiling Avater, until the whole is dissolved and evaporated to a specilic gra- Yity of 1.25, at which point the carbonic acid of the atmospheric air ceases to decomjiose it. The highest concentration of the liquid is 42*''' B; when still more evaporated it is obtained in a solid form, re- sembling common glass, bnt much softer and more fusible. The liquid standing about 30^ B is, how- ever, the most proper menstruum for application to wood, and preventing the same from being attacked or kindled bj sparks of fire, such as shingle roofs, wooden bridges and farm houses. Fuchs prepared four different liquids, and employed them in his ex- periments : 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 fireproof, and on the occasion of the burning of the Royal 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- SOLUBLE GLASS. 15 tiire, without pnuhicino- a lite tire; and from that time tlie water glass was introduced in Germany. A few years later the same liquid Avas introduced in the mauufacturiuir districts of England as a substi- tute for cow's dung by the cotton mills, and was called " Dunging Salt." The author having studied with Doebereiner, a professor of practical chemistry in Jena, who was engaged in experiments on water glass, and who proposed an alteration in its composition, such as the compcamd of potash and soda, or 72 parts of carbon- ate of potash, 854- parts of carbonate of soda, and 152 parts of finely pulverized quartz, which proved to be a better substance, conceived the idea that water glass may be profitably employed in this country for many purposes. In company with ship captains and builders he offered to substitute it for coppering ves- sels, 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 in- considerable expense, in the Brooklyn Navy Yard, he was permitted by the Ordnance Department, under the direction of Commodore Perry, then the Captain of the Yard, to perform the experiments witji the spiles on the various docks, which were destroyed SOLUBLE GLASS. by tlie worms {Teredo navaUs) so fast that tliey had to be replaced every three years. Also the cannon balls, exposed to the weather, becoming rusty and w^orthless in a few years, w^ere varnished with his own preparation, and the addition of asphaltum, and his experiments proved highly satisfactory, as in both instances of applications many years afterwards indi- cated their preservation. The water glass was neglet^ted for many years ex- cept by the military authorities in Prussia, and we hear that the soldiers Avere instructed to wash their linen, and the State Prison at Si)andau introduced it for washing the prisoners' under garments ; and it was proved so economical that one gallon of concen- trated liquid was sufficient for washing 1,000 pieces. Tiie 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 orna- menting the interior of houses. Pie 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, com- bining with the silicic acid of the silicate of potash, becoming converted into silico carbonate of lime, 'SOLUBLE GLASS 17 the carbonic acid, thus set free, combined with the potash, in time, particularly when assisted by lieat and dry air, the coating of silico carbonate was found to pass into a true compact deposit of silica, hard enough to scratcli 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 .ap]>lication8 were considered suffi- cient. Although successful in the laboratory, this method failed when applied to buildings, because a dry atmosphere is needed during tlie whole period of hardening. Not long after this suggestion had been made by Knhlman, the English manufacturer, Ean- some, of Ipswich, engaged in the manufacture of silicate of soda, following up the above experiments, attempted to fix the solution, when absorbed with the stone, to produce a double decomposition by absorbing another soluticm, thus leaving an insoluble deposit within the sul)stance of the absorbent stones on which it was desired to act. He found that, l)y a weak acid solution, he could set free the silica, but in that state the deposited mineral had no cohesion. Following up, however, the application of the fluid silicate by a small portion of chloride of calcium (a waste product from the salines and acetic acid manu- facturers), it resulted that the chlorine, parting from the calcium, attacked the soda of the silicate, forming common salt, which is easily dissolved away, while 18 SOLUBLE GLASS. the silica acid, set free and combining with the lime, formed with it silicate of lime: This mineral is nearl)^ insolnble, very hard, and adheres with great tenacity to foreign snbstances, as is illnstrated in common mortar. Silicate of lime thus formed resists carbonic acid and dilute sulphuric acid, and is little aliected by any of the comrnon alkalies or ammonia. The etFect of this treatment on stones that have not already been inserted into buildings has been very favorable, and they appear to have stood without dcca}^ under exposures sufficient to produce 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 wdll be able to see the result in the Houses of Parlia- ment and Westmhister Abbey, where the magnesian limestone has been treated by this process. A combination of Kuhlman's process with a tempo- rary wash of some bituminous substance has been tried on a large Fcale in the Speaker's (^ourt 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 silicate, or soluble glass, has only been known since our present time, although the various kinds of glass, imitation of gems, belongs to antiquity, for Pliny SOLUBLE GLASS. 19 states " that glass was first discovered by accident in Syria, at the mouth of the river Belus, by certain mercliants driven thitlicr by the fortune of the sea, and obliged to continue there and drt^ss their victuals by making a fire on the ground, where there being great store of the herb hali^ 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 s])ecies 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 hea])S, either on the ground or on iron grates, the ashes falling into a })it, gj*ow into a hard mass or stone, fit for use." This material evidently means the kelp, Avhich was burnt and converted into Barilla. It is also certain that Kunkel, in U)Y9, states that the art of glass was already brought to its highest perfection, and expressed that Neri in his treatise, " l)e Arte Vitraria," has communicated complete knowledge of artificial gems — much is said of flexible glass not rotting, of a fusible or soluble glass, of which Ya i llelmont, the chemist of the first part of the seventeenth century, knew nothing. The improvements in the manufacture of the soluble 20 SOLUBLE GLASS. glass, particularly tliat of soda, were of great im- portance. He had, in the first place, discarded the sand, which he did not find compact enongh for pro- ducing a good paint, and substituted the flints, found in the chalk : this species of silex he exposes under a pressure of 7-8 atmosplieric, in an iron cauldron, to a hot soda lye standing 88®, which process was pa- tented by the brothers Siemens, in the year 1845, with this diU'erence, that they produce a liquid at a very high temperature corresponding in vapors of 4-5 atmospheres, by which process they obtain for 3-4 time 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 ])ure 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 an nually formed in the harbor of Wismar, in the Baltic Sea ; the deposit of infusorial earth in Richmond, Ya., contains over 100 species, and forms a thick stratum. SILEX, OR SILICA. This substance is an oxyde of silicinni, and bein^ tlie main body of onr preparation deseryes a full and detailed description. Silicium is the metallic basis of silica, or silex, and is equally abundant \yith oxygen as a constituent of the solid surface of the globe, and also constituting a large portion of aerolites, from the regions of space, and this metallic base was discovered by Eerzelius, in 1S23, and is obtained artilicially in the following manner: — Weil dried silico Huoride 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 lluoride and siliciuret of potassiimi. It is thrown in cold water, when hydro- gen is evolved, the potassium of the silica not being oxydized by water and the silicium separating. AVhen 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 1* 22 SILEX, OR SILICA. 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 air or oxygen, or even when gently ignited with saltpetre. Silica, or oxide of silicium, is synonymous with silicic acid, silex and pure sand, or quartz, in its various forms and appearances, and constitutes a very large proportion of the solid crust of the globe, dnd is the principal constituent of all simple mine- rals, and forms a greater variety of salts than any other acid. It is easily prepared pure from pow- dered quartz, sand, Felspar, 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, dissolving when in dilute muriatic acid, filtering and evaporating the solution to dryness by a gentle heat, 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 v>ith alkalies, but may also be formed by boiling fine Silex with strong alkaline solutions. SI LEX, OR SILICA. 23 It is soluble in water and acids, and when the so- lutions are concentrated it usually separates as a jell J [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 fur- naces, 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 dropped in water, it becomes so hard as to indent a steel pestle and mortar. It is the feeblest acid at common tempera- tures, but by a high heat can expel all volatile acids. Quartz is found in nature crystallized in a great variety of forms, the rhombohedral prevailing, and for the most part hemihedral 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 eflected by plunging a heated crystal in cold water. The 24 SILEX, OR SILICA. crystals are either very short or very much elon- gated, sometimes line aciciilar usually implanted by one extremity of the prism, occasionally twisted or b'3nt. 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 ^^"ew York, produce quartz crystals of the most complicated forms, which occur from the size of a pin's head to that of a foot. Quarts is also found massive, from the coarse or fine granular to flint-like or crypto-crystalline ; sometimes mamillary stalactitic, and in connectionary forms. Quartz has a hardness — T, and a specific gravity of 2.65 ; a vitreous lustre sometimes inclining to resin- ous ; 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 as the colors, but much paler. Quartz is transparent and opaque ; its fracture is perfect conchoidal and sub- conchoidal, is tough, brittle and friable. The polar- ization 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 STLEX, OR SILICA. 25 the right in right-liaiided 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 circnlarlv, and the other plane. Pure silica, which has the symbol of Si, consists of 58-83 parts oxygen, and 46-67 silicon — 100. It is unaltered if brought alone before the blow-pipe, but with soda, it dissolves with eti'ervescence ; it m unacted upon by any salt of phosphorus ; it is only soluble in iluohydric acid. There arc two varieties of quartz in existence — I. The crystallized, or [)henocrystalline, which is vitreous in lustre. II. The fluid-like, massive, or cryi)to-crystalline. The tirst division includes all ordinary vitreous quartz, whether having crystalline faces or not ; while the second variety has been acted upon some- what more by attrition and chemical agents, as fluo- ric acid, than those of the flrst. The following species of quartz belong to the phe- nocrystalline, or vitreous varieties: 1. The ordinary crystallized quartz, rock crystal, which is the colorless (piartz, or nearly so, whether in distinct crystals or not. a. The regular crystals, or limpid quartz. b. The right-handed crystals. c. Left-handed crystals. 26 SILEX, OR SILICA. d. Cavernous crystals, having deep cavities par- allel to the faces, occasioned by the inter- ference of impurities during their forma- tion. e. Cap quartz, made up of separable layers or caps, one to the deposit of a little clayey material at intervals in tlie progress of the crystal. f. Drusy quartz, a crust of small or minute quartz crystals. g. Kadiated quartz, often separable into radia- ted parts, having pyramidal terminations. A. Fibrous, rarely delicately so, from Cape of Good Hope. 2. Asteriated quartz, star quartz, containing within the crystal whitish or colored radiations along the diametral planes. Part, if not all, asteriated quartz is asteriated in polarization, as already remarked. 3. Amethystine quartz, amethyst, clear purple or * blueish- violet ; the color 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, common, massive ; and then usually 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. SILEX, OK SILICA. 27 5. Yellow, talse topaz, yellow and pellucid, or nearly so, resembling somewhat yellow topaz ; but very ditferant in crystallization, and in absence ot cleavage. 6. Smoky quartz ; the Cairngorm stone. It is smoky yellow to smoky l)rowni, and often transpa- rent, 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 local- ity in Scotland. 7. Milky, milk white, and nearly opaque ; lustre often greasy, called then greasy quartz. 8. Siderite, or sapphire quartz, of indigo, or Ber- lin blue colors. A variety of quartz occurring in an impure limestone at Golling, in Salzburg. 9. Sagenitic, containing within acicular crystals ot other minerals : these acicular crystals may be rutile, or black Tourmaline, or Goethite, stilbite, asbestos, actinolite, hornblende, or epidote. 10. Cat's eye, exhibiting oj^alescence, but without prismatic colors, especially when cut in cabochon, an etl'ect due to fibres of asbestos. 11. Aventurine quartz, spangled with scales ot mica or other mineral. 12. Impure quartz, from the i)rcsence of distinct minerals distributed densely through the mass, such as ferruginous, either red or yellow oxide of iron, 28 SILEX, OR SILICA. cliloritie from elilorite, aetinolitic, micaceous, arena- ceous owing to sand. Quartz crystals also occur penetrated by various minerals as topaz, corundum, clirysoberyl, garnet, difl'erent species of hornblende and Pyroxene groups, kyanite, zeolites, calcite and other carbonates of lu- tile, htilbite, hematite, Goethite, magnetite, fluorite, gold, silver, anthracite, &c. As quartz has been crystallized 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 rea- son why 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-crystalline varieties of quartz are the follow^ing : 1. Chalcedony; it has the lustre nearly of wax, and is either transparent or translucent ; the color is wdiite 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 occur- ing lining or tilling cavities in rocks. SILEX, OK SILICA. 29 2. Carnelian ; a clear red chalcedony, pale to deep ill 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. 4. Prase; translucent and dull leek green; taking its name from the Greek npooaov^ a leek. 5. Plasma ; a rather bright green to leek green, and sometimes nearly emerald green color, and sub- translncent or feebly translucent, sometimes dotted with wliite. Heliotrope, or bloodstone, is the same stone essen- tially, with small spots of red jas])er, looking like drops of blood. The jasper of the ancients was a semi-transparent or translucent stone, and included, in Plim^'s time, all bright colored chah-edony, excepting the carne- lian ; the same author gives special prominence to sky blue and green, and mentions also a shade of purple, a rose coloi", the color of the morning sky in autumn ; sea green, sepcnthine color (yellow, like sepentine), 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 im- purities. (Banded agate), where the bands form delicate parallel lines of white, tendonlike, waxlike, })ale and 30 8ILEX, OR SILICA. 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 fine translucent agates gradu- ated 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 intermittently supplied in irregular cavities in rocks, and deriving their concentric waving courses from the irregularities of the walls of* the cavity. As the cavity cannot contain enough of the solution to fill it witli silica, an open hole has been supposed to be retained on one side to j)ermit 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 of oxides of iron, manganese, or titanium, and largely to differences in rate of deposition. The layers dif- fer in porosity, and therefore in the rate at which they are etched by fluoric acid, and consequently the etching process brings out the different layers, and makes engravings that will print exact pictures of the agate. Owing also to the unequal porosity, agatei may be varied in color by artificial means. Irregularly clouded agate, the colors various, as in banded agate. SILEX, OK SILICA. 31 A whitisli, clouded variety, which Pliny has de- scribed and given fully the characters. Y. ( 'olored agate, due to visible impurities ; a moss agate, or mocha stone, tilled with brown moss- like or (lentritic Ibrms, distributed through the mass of dentritic agate, containing brown or black den- tritic markings. These two have been fully de- scribed by Pliny as dentrachates. There are also eight agatized woods, wood petriMed with clouded agate. 7. Onyx, like agate, in consisting of layers of different 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 serving as the background. The colors of the best are perfectly well defined, and white and black, or white, brown and Idack alternate. S. 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 witli veinings and cloudings of chalcedony. 10. Siliceous sinter. Irregularly celluhu- (piartz, 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 32 silp:x, or silica. brown, and browninli black. Tlie exterior is often whitish, from mixture with lime or chalk, in which it is imbedded. Lnstre barely glistening, subvitre- ons ; breaks with a deeply conchoidal fracture and a sliarp 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, ])artly soluble silica. 12. Ilornstone. 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. Basanite, lydian 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 com- pact, fissile, siliceous or flinty rock of grayisli or other colors, called siliceous slate, and resembles ordinary jasper, of various shades. 14. Jasper. An impure opaque colored quartz. a. The reducing to hematite, or sesquioxide of iron. 1). The yellow or brown, colored by the 'hydrous sesquioxide of iron, and becoming red when so lieated as to drive ofl' the water. SILEX, OR SILICA. 33 e. The dark green and brownish green. d. Tlie grajisli 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 ii] being fusible on the edges before the blowpipe. Ked 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 comj)acted, 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. Itaoolumite, or flexible sandstone.. A friable sand rock, consisting mainly of quartz sand, but con- taining a little talc, and possessing a degree of flex- ibility when in thin laminae. 5. Buhrstone. A cellular flinty rock, having the nature in part of coarse chalcedony. C. Pseudomorplious quarts. Quartz appears also 34 SILEX, OR SILICA. under the forms of many of the mineral species, wLicli it lias taken through either the alteration or replacement of crystals of those species. The most common quartz, pseudomorphs, are those of caleite, baryta, flnorite and siderite. Tabular quartz, Hay- torite, Beckite, Babel quartz, silicified shells and silicified 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 foinied 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 solu- ble alkaline silicate.'*' Quartz is one of the essential constituents of gran- ite, syenite, gneiss, mica, shist and many related rocks. As the principal constituent of quartz rock and many sandstones, as an unessential 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 chalcedony, agate, carnelian, ifec, as imbedded nodules or masses in various lime- stones containing the flint of the chalk formation, 81LEX, OR SILICA. 35 the hornstone of other limestones ; these iiodnles becoming sometimes layers or masses of jasper oc- casionally 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 mine- rals composed either solely of silica, with slight va- riations in their degree of hardness or specific gravity^ such as the following : The opal, which is sub-divided, in 1. The precious opal^ exhibiting a play of delicate colors. 2. The fine opal^ 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. Kesin 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. 5. Gachelong. Opaque and bluish white, porcelain white ; often adheres to the tongue. 36 SILEX, OR SILICA. 6. Opal agate. Agatelike in structure, but con- sisting of opal of different shades of color. 7. 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. 9. Wood opal. Wood petrified by opal. 10. Hyalite. Clear as glass and colorless, consti- tuting globular concretions and crusts. 11. Florite^ or siliceous sinter; also called pearl sinter, from Santa Flora, in Italy, and other vol- canic rocks, formed from the decomposition of the siliceous minerals of volcanic rocks, or from the sili- ceous w^aters of hot springs. 12. Float stone ; also called s^vimming 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 earthy 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. Randanite ; a kaolin-like variety from France. c. Tripoli slate. A slaty or thin laminated va- riety ; fragile, often mixed with clay, mag- nesia and oxide of iron. SILEX, OR SILICA. 3r d. Alumocalcite. A milk-wliite material, very light, having a hardness of only 1 to IJ, and a sp. gr. of 2.174, 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 does not. 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 con- sists 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 mor- tar. There are several varieties of the sandstone, such as micaceous^ argillaceous^ marly and flexible. Common sand is mainly comminuted quartz. Gravel is a mixture of sand with pebbles. Yolcaiiic sand is sand of volcanic origin : either the cinders or ashes or comminuted lava. Alluvial sand is the earth deposited by running streams, especially during times of flood ; 2 38 SILEX, OR SILICA. it constitutes the flats on either side of the stream, and is usually in thin layers, varying in fineness or coarseness, being the result of successive depositions. In order to use the sand for the manufacture of solu- ble glass, which shall equal that manufactured from flint, or infusorial or siliceous earth, it is best to di- gest the sand witli chlorohydric acid, which is capable of dissolving all the foreign substances, and then by frequent washings and drying 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 various chemical tests, such as by ammonia, the iron ; by oxalate of ammonia, the lime ; and clay, by carbonate of soda. If the pure crystallized quartz, flint or hornstone should be used for the manufacture, the same must be reduced into coarse or granular condition, which is efl*ected by calcining the mineral, and when red hot, cold water is thrown over it, whereby it becomes disintegrated 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 sili- cates : 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 com- pounds with the addition of many other bases in na- ture, that there are very few mineral substances known 8ILEX, OR SILICA. 39 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 sub-divided, as 1. Bi- silicates; 2. Unisilicates ; and 3. Siih-silicaies ; 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 felspar, 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, cliabasite, stilbite, heulandite, &c. In the manufacture of soluble glass, the alkali is in importance next to the quartz or silica such 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 wash- ing 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 employed in the manufacture is the soda ash of commerce, and is never pure enough, 40 SILEX, OR SILICA. containing water and other salts, which ought to be removed from it bj dissolving, crystallizing, and then calcination of the crystals. Sulphate of soda^ or Glauber salt, has been used by some manufacturers in place of soda ash, which ought not be employed, as the same is partly con- verted 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 produc- tion of hard cements, the fluohydric acid is of great service, for it assists in the hardening of the mortar, and forming a good, permanent cement. WJdte 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 are used. 0 THE MANUFACTURE OF SOLUBLE GLASS. 1. 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 beat until the mass after six hours has become vitrified. Charcoal is employed for assisting, by its decomposition, the production of carbonic acid, as also some sulphuric acid which may have been produced. It is at present, however, omitted, and if manufactured on a large scale the vitrification is done in a reverboratory furnace capa- ble of holding from 1,200 to 1,500 pounds. The ashes and sand must be well mixed together for some time and the furnace must be very hot before throwing the mixture 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 throwni upon a stone hearth and left to cool. The glass mass so ob- tained appears to be hard' and blistery, of blackish gray color, and if the ashes were not quite pure it will also be adulterated with foreign salts. By pul- verizing and exposing it to the air it will absorb 42 MANUFACTURE OF SOLUBLE GLASS. the acidity, 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 quantity of hot water, in small portions, and with constant agita- tion, and replacing occasionally hot water for that which evaporated during the boiling, and after five or six hours the entire mass is dissolved ; the licpiid is re- moved and left to settle over night, in order to be able to separate any undecomposed silex. The next day it is evaporated still more until it has assumed the consistency of a syrup, and standing ^S'^'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 an}^ salts do efier- vesce they may be wiped off. The color is not quite white, but assumes a greenish or yellowish white color. II. 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 char- coal, 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 aBliydrous glauber salt MANUFACTURE OF SOLUBLF: GLASS. 43 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 dis- solving the fine silex in caustic soda lye. Kuhlman employs the powdered flint, which is dissolved in an iron cauldron under a pressure of 7 to 8 atmospheres. According to Liebig the infusorial earth is recom- mended in place of sand on account of being readily soluble in caustic lye, and lie proposes to use 120 parts infusorial earth to 75 ])arta caustic soda, from which 240 parts silica jelly may be obtained. His mode is to calcine the earth so as to become of white Colors, and passing it through sieves. 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 deg. B ; in this boiling lye 120 ounces of the prepared infusorial earth are added by degrees, and very readily dis- solved, leaving scarcely any sediment. It has then to undergo several operations for making it suitable for use, sucli as treating again with lime water, l)oiling it and separate any precipate forming thereby, which by continued boiling forms into balls, and whicii can then be separated from the' liquid. This clear li(|uid is then evaporated to consistency of syrup, forms a jelly slightly colored, feels dry and not sticky, and is easily soluble in boiling water. 44 MANUFACTURE OF SOLUBLE GLASS. The difference between potash and soda soluble glass is not material ; the first may be preferred in white washing with plaster of Paris, while the soda glass is more fluidly divisible. It may be observed that before applying either soluble glass, it ought to be exposed to the air for ten to twelve days, in order to allow an effloresence 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 dry- ness forms a vitreous solid glass which cannot be scratched 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 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 MANUFACTURE OF SOLUBLE GLASS. 45; it assumes a more condensed amount of silica with the alkalies ; and which solution has been found to work well for paint. Siemen's patent for the manu- facture 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 cor- responding to 4-5 atmospheres, with the common caustic alkalies, which are hereby capacitated to dis- solve 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 per- sons, many years later, obtained a patent for the same apparatus in the United States, which on inspection does not differ from that of Siemens Brothers. Description of Siemen's Apparatus for dissolving silica in soda lye, under a pressure of five atmos- pheres, or sixty pounds to the square inch. 2* 46 MANUFACTURE OF SOLUBLE GLASS. The whole apparatus consists of the boiler A, and the dissolving kettle B. Fig. I 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 1) of the width of 1-2 inches. The steam passes through the pipe a into the space J. In order to reach the mner 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, yy, are now applied with a wheel g at the end for effecting the revolutionary movement*. The steam- cocks K as seen at the front wall r oof paints^ cements^ varnishes, etc., for which pur- poses the daily demands are sufficient proofs. 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. " 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 natu- ral 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 MANUFACTURE OF SOLUBLE GLASS. 53 good cellar and roofing cement is made bj adding to this mass tliree parts of white sand. " The silicate is also used for penetrating firebrick and clay, in order to make them more fireproof, and ajso 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 the 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 bet^n 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 tlieir action. The labors of Fuch, Lie- big, Kuhlman, Vicat, Temy, Guerin and llansome 54 MANUFACTURE OT SOLUBLE GLASS, have fairly begun their work, and in ten years more the ship builder, 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 Ran- some, which consists in the following manner : 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 by 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 chisseled 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 tlie chloride of calcium is promoted in closed chambers connected with a steam boiler. When this has been carried on for a sutiScient 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 MANUFACTURE OF SOLUBLE GLASS. 55 masses are exposed to rapid extremes of temperature in the open air. In order to remove or extract the sohible 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 returnt d into the boiler, where the steam is generated, and the chloride of calcium is again made available for future operations, thus obviating the serious loss incurred by washing the stone in the way hitherto adopted. Mr. li. was led to his last experiments from the many faults which he 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 bright red the cementing 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 MANUFACTURE OF SOLUBLE GLASS. 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 ^itmosplieric action and even absorb tioii. Paving slabs, garden vases, balusters, tombstones and various .a,rcliitectaral features, often constructed of terra cotta, were produced of superior quality and greater dura- l)ility. 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 reacliing to a satisfactory result. The author has, many years ago in the course of his experiments, succeeded in preparing an artificial «tone in the following manner : — Fluorspar, finely ^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 MANUFACTURE OF SOLUBLE GLASS. 5T is then exposed again to the atmosphere for a week-; a dilute hydro-fluoric 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 inoulded, are exposed to hydraulic pressure, and then exposed to the air^ previous to which the chloride of clalcium has to be throw^n over it. The price of hydro-fluoric acid, as is used for this purpose, costs about 26 cents per pound, and this suftices for ten square feet. It must be, however, observed, that the soluble glass used in this process was the potash silica and not the soda silicate, as he found by his experiments to be indis- pensable, the soda silicate does not produce that du- rability and hardness that the potash silicate. Furthermore it may be remarked, that exposing the stone so prepared may be subjected to a high temperature or not ; it may be left to the operator to decide whether it will improve the stone by this ma- nipulation. For the sandstone imitation, when 1 part liquid soluble glass is to be mixed with 2 parts powdered soluble glass, and 15 parts of sand is added, it is ne- 58 MANUFACTURE OF SOLUBLE GLASS. cessary to expose the mass to great pressure, but requires 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 once converted into silicate of lime aid carbonate of soda ■or potash : this composition, when exposed to the air, becomes 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 cracks and crevices in marble works and monuments. Tlie silification 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 solution has shown that the hardening of the chalk extended 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 gh where the carbonic acid of the atmosphere is withdrawn, the first will acquire more hardness than the other, which proves that the silification has assumed a hydrate of silico — MANUFACTURE OF SOLUBLE GLASS. 59 carbonate of lime — which looses by degrees its water of crystallization and a contracting precipitate of si- lica, which contributes mainly to the hardening of the stone. A hydraulic lime may be obtained by the mix- ture of a fat or rich limestone combined with solu- ble glass in a dry state, say 10 parts silicate to lOCTparts of air lime, both fine powder, which proves plainly the theory of the part which the silicates play in the production of the native limestone, the artificial hydraulic lime, mortar, cements, and the. application of all silicates for the purposes of build- ing, production of artificial stones, and the conver- sion of organic into inorganic materials, as we shall show hereafter. HYDRAULIC LIMESTONE, CEMENTS AND PLASTERS. It is necessary to explain the main material -Hised in building, which is lime, before we can proceed farther 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 Anted's lectures on practical geology, the following 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 and familiar is called mortar. It is obtained by first cal- cm ing common limestone in a kiln, and converting it into qnick lime, by depriving it of its carbonic acid. After calv "aing, the resulting quicklime is a whitish or grayish pow^dery and cracked substance, which, on the application of water, absorbs a certain quantity with the evolutioiv of much heat, and falls into a fine powder. This powul-^r, further moistened, made into a thin paste with watei-,^nd mixed with two to three times its own weight of siv.arp sand, is called mortar. HYDRAULIC LmESTONE, CEMENTS, ETC. €)1 Slaked lime, or hydrate of lime, as moistened quick- lime is called, absorbs carbonic acid from the air, and in time mortar is reconverted into limestone ; but the operation goes on under peculiar conditions, and the result 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 the par- ticles of limestone. "As, however, there are different kinds of limestone, more or less impure, the result will be limes of very different qualities and properties. These require spe- cial treatment to obtain from them the best results. The purest carbonate of lime, such as marble, or chalk, make what is called a rich lime, setting firmly only in dry air, while the very impure carbonates, in which clay is largely mixed with the limestone, re- sult 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 manu- facture of cements by the admixture of definite pro- portions of foreign ingredients. Some ' .les by the admixture of certain substances [as puzzuolana] with the rich limes instead of sand hydraulic limes are produced. There are few subje ts connected with the application of geology th- ^ are more important than the determination of t\e material that should be used and the treatment adopted in various countries 8 62 HYDRAULIC LIMESTONE, 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 ; 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 sub- stances with extraordinary tenacity. But this is a work of years, and sometimes even centuries must run out before the extreme of hardness is attained ! It is not unusual to find imperfectly hardened mor- tars in very old constructions. The mortar that fast- ened together the bricks in the old Roman walls is now almost everywhere so far hardened that a frac- ture takes place in the brick rather than th*^ .cment. " Limestone is widely distributed, \ Irnost every variety, however impure, can be burnt for 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, other things being the same, but each variety yields a lime of different quality, distinct in color, in weight, in the greediness with which it ab- sorbs water, and in its ultimate hardness. The method of calcination also varies, but the general j-esult is that, after burning the limestone, the result- CEMENTS, ETC. 63 ing quicklime is lighter than tlie original stone, and differs from it essentially. To determine the nature of lime, and its peculiar properties, perfectly 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 off, 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 come one of 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 seme short time, not exceeding five or six minutes, after which the results stated in (1) will be eiiergetically declared. " 3. It will remain inert for more than five mi- nutes, sometimes extending to a quarter of an hour; it then gives otf 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 HYDRAULIC LIMESTONE, 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 a 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 this 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 mate rials used, which may belong to one of five classes— (1.) Kicb Limes. (2.) Poor limes. (3.) Moderately hydraulic limes. (4.) Hydraulic limes. (5.) Eminently hydraulic limes. " The w^ord hydraulic, as applied to lime, means only, that it possesses the property of setting, or be- coming solid, in moist air or under water. " Eich 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 that contain from 1-6 per cent. 43f foreign substances, such as silica, alumina, magne- sia, (fee., yield rich limes ; but such contain frx^m CEMENTS, ETC. 65- 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 fossiliterous 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 pure 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 ob- tained naturally from the burning of certain varie- ties of calcareous rock, or are manufactured artifici- ally by mixing limestones with the requisite foreign ingredients, or by combining quick lime with foreign materials, such are the Roman cement, Portland ce- ment, Parker's and Rosendale cements. The Port- land cement is largely manufactured at the mouth of the Thames from a mixed river mud, while Roman cement is formed from the nodules found in the cliffs near Harwich, all owing their quality to argillaceous admixture and limestone containing from 15 to 25 per cent, of a silicate of alurania, will burn into a good hydraulic lime. It is also quite certain that the 66 HYDRAULIC LIMESTONE, oxide of iron and carbonate of magnesia exercise a great influence in rendering limes more hydraulic. All materials intended for the manufacture of ce- ments require to be burnt carefully and ground down to a fine powder, 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 cements, just described, w^ill bear a strain vary- ing 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 lime- Btone for a cement. The calcining of gypsum does not involve its decomposition, but the water of solid- ification 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 origi- nal condition as a crystalline mineral, but it is con- verted into various substances used as cement, such as Keene'^s cement, if alum is added to the fine pow- dered plaster ; parian cement, if borax is used ; Martin's cement, if pearl ashes are employed ; a stucco is a very useful material for ornaments in in and out-door work, is nothing else but a plaster of CEMENTS, ETC. 6T 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 Xaples, as well as other substances found in large quantities in the neighborhood of extinct volcanic districts, as in France and on the Rhine; and which, according to its chemical analysis, coiisists of 44 per cent, of silica, 15 per cent, alumina, 87 }>er cent, lime, 4 per cent, magnesia, and 12 per cent, oxide of iron ; combined with lime instead of fand, have the property of rendering even the richest limes hydrau- lic, and fit for use for every description of works exe- cuted in the sea or in fresh water ; they have been used from time immemorial 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 dilferent chemi- cal actions : 1. To the hydration of the aluminates 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 compounds of these two substances, those, for instance, containing from 80 to 90 per cent, of 68 HYDRAULIC LIMESTONE, lime, may be useful in the iron furnace for absorbing sulpliur and phosphorus, and free the metal from those noxious impurities ; and he finds that no sub- stance is capable of acting as a puzzuolana except the simple or double silicates of lime, containing only from 30-40 per. cent, silicate, and sufHciently basic to form a gelatinous precipitate with acid ; and he confirnts Yicat's theory, that the cause of the setting of hydraulic cements was owing to the formation of a double silicate of alumina and lime absorbing wa- ters, forming hydrates and causing the setting of the materials. " Theory of Hydraulicity. " Fremy has lately published his researches on hydraulic cements, and in giving the theory of their hydraulicity, he rejects the commonly received opi- nion that the setting of hydraulic cement is due to the hydration of the silicate of lime or that of double silicate of alumina and lime. These salts form no combination whatever. He attributes the setting of hydraulic lime to two chemical actions : 1st. To the hydration of the aluminate of lime ; 2d. To the re- action of hydrate 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 3)roduce3 good hydraulic cement only when the pro- CEMENTS, ETC. 69 portions of clay and lime are such that they form in the first place, an aluminate of lime, represented by one of the following formulae : Al O3 Ca O — Al^ O3 2 Ca O ;— Al, O3 3 Ca O ; in the second place a very simple or multiple silicate of lime which gelati- nizes with acids and approximates to the following formulae :— Si O, 2 Ca O— Si O, 3 Ca 6 ; and thirdly, free lime which may act upon the preceding puzzuo- lanic silicates. " In many cases the chemical compo?ition of an argillaceous limestone is not only the condition which 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 re- quires, and which, by melting the aluminate of lime, gives it all its activity. " HYDRAULicrrY OF Magnesia Hydrates. " Since the publication of Fremy's paper, Deville has read a note before the Academy of Sciences, ' On the Ilydraulicity of Magnesia,' in which he alludes to a specimen of magnesia prepared by the calcina- tion 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, 3* HYDRAULIC LIMESTONE, became liard enough to scratch marble, and was clear as alabaster. After six years exposure to the air, it has not perceptibly 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 crystallized hydrate of magnesia, like brucite, which does not absorb carbonic acid. To prove that it was really so, M. Devil] e prepared magnesia by calcining the nitrate, powdered it, made it into a plastic mte, and sealed in a tube with some boiled distilled water. After some weeks, the mass became as hard and com- pact as the otlier, and also crystalline and translucid. After drying in the air, this mass was found to con- sist of 30.7 per cent, w^ater, 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 w^ater for some time, becomes hydrated and extremely hard. CEMENTS, ETC. 71 Deville finds that dolomite rich in magnesia^ when calcined below a red heat, powdered and made into a paste, forms, under water, a stone of extraor- dinary hardness. When dolomite is heated to bright redness and all the chalk is converted to quick lime, the paste formed with it breaks up under water. All these important experiments of Deville, show that magnesia is the binding material which, on becom- ing hjdrated, holds together the particles of chalk or marble, and thus forms a compact, homogenous - stone. " Hydraulic Cements. " Hydraulic cements owe their property of setting to some compound formed by the calcination of infe- rior limestones containing clay and silica. AVhat the chauge is that is produced by the calcination has hitherto not been sufficiently well understood to ena- ble the manufacturers of cements to work with abso- lute certainty of producing a uniform product. M. Fremy has recently been studying the subject, and has communicated his observations to the Institute of France. He found that the calcination of a calca- reous clay gives rise to an aluminate of lime and a silicate of lime, with some free caustic lime. " It is this mixture that hardens when brought in contact with water. According to Fremy the setting of the cement is due to the hydration of the alumi- T2 HYDRAULIC LIMESTONE, nate of lime and the combination of silica with the quick lime. The presence of four compounds is ne- cessary to a good result: 1, silicate of lime; 2, sili- cate of alumina; 3, aluminate of lime ; 4, caustic lime. Fremy prepared every one of these com- pounds, and studied them separately and together. He made the interesting observation that alumina was an excellent flux for lime, and combined with it quite as readily as silica. " The calcareous clays, or poor sorts of limestones^ which are capable of setting under water, do not acquire that property until they have been exposed to a high heat. One of the secrets of the preparation of Portland cement is the high temperature employed in its calcination. The lime and alumina must be fused to secure the property of hydration. The alu- minate of lime is the most important agent in hy- draulic cements. " Hydraulic limestones will not yield a good cement unless the proportion of clay and lime be such as to form a compound of alumina, with one, two or three of lime, and the silica and lime be in the proportion to yield a bibasic or tribasic silicate of lime, which will gelatinize with acids, and there must be an excess of lime to be left over in a caustic state. The presence of magnesia, manganese or iron, is not at all necessary, although the latter is always con- tained in the poorer limestones. CEMENTS, ETC. 7S " An average sample of Portland cement will yield, upon analysis, in one hundred parts : Lime, fifty-five ; iron, seven ; alumina, eight ; silica, twenty- four ; potash and soda, three ; sand, two ; water, one. The essential constituents are the lime, alumina and silica." The Author delivered a discourse on cements be- fore the Polytechnic Association, 2Gth April, 1866, of which the following is the substance : Cements. " Tlie subject for the evening — cements — was here taken up, when Dr. Lewis Feuclitwanger exhibited a number of minerals used in diil'erent kinds of ce- ments, and read the following paper : " ' The meaning of cement is, a paste used for unit- ins: 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 and do not combine chemically ; others again form chemical combinations. Furthermore, many sub- stances are capable of assuming a liquid or semi- fluid form, and are thus applied betw^een 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 ; T4 HYDRAULIC LIMESTONE, 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 branch of the subject, premising, however, that •common 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 saud, not round, but angular ; these, wdth oue and one-half cubic feet of water, produce about three and one-half cubic feet of good mortar. " ' Hydraulic or Roman cement is composed of cer- tain proportions of lime, sand, clay and water : after it has been applied a few days, and placed under water, it becomes very hard and like stone. We now find walls and piers which are kuown to have been built more than a hundred years ago, and have been exposed under water, and have remained as solid as iron. The name Koman cement is derived from the district of Fuzzuoli, near Naples, 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 afforded a natural cement, for they are composed of silica, alumina and lime. Besides these tufas, many marls, belonging to the sedimentary rocks, are used as hy- draulic cement. The cement stones allied to the oolitic formation and found in argillaceous strata CEMENTS, ETC. alternating with limestone beds, and of very curious nodular and lenicular forms and concretions, on the English and French coasts, and in this country the septaria, toadstones, Indus hclmontii of various sizes and consisting of siliceous clay and lime strata inter- woven, yield the proper material for hydraulic ce- ment. All these marls contain, according to analysis, about seventy per cent, of carbonate of lime, twenty per cent, of silica, and twenty per cent, of clay, and the lime when calcined becomes caustic, and, in com- bination 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 — CO —Si O3--AI, O3. " ' The Roman 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 tliese substances exercise a pernicious influence, for the reason that dolomite, a mao-nesian limestone found in ffreat abundance in this country, offers a fine material when calcined with any marls so abundant along our coast. It produces an excellent hydraulic cement. " ' The analysis of the hydraulic lime from Rondout, on the North River, gives in one hundred parts : Carbonic acid 35 Magnesia 12 Alumina 10 Lime 2") Silica 15 Iron 2 76 HYDRAULIC LIMESTONE, " ' Sand or quartz, which by itself is unfit for a mortar, when calcined with lime becomes very suit- able for a hydraulic cement or artificial stone, for it forms a silicate of lime. More than thirty years ago, I entertained the idea of preserving timber by the infiltration of silicate of lime into the cells of planks, timber, and through tlie 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 w^ater-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 tlie foundation of buildings. Having made, myself, many experiments, for a number of years 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 ofi'er here a sample of a cement which consists of silicate of lime combined with manganese and fluor- spar, or fluoride of calcium, which becomes very hard, and which, I think, will, after some improve- ment in the preparation, 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 ; CEMKNTS, ETC. 7T after the lapse of a few hours it becomes v^ery hard. " ' Fire 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 acceptable. 1 beg to offer a few which I consider useful : ' No. 1. lro?i Cement or Lute. — Brick 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. — Two parts- litharge, one part sand, one j)art slacked lime; made plastic with hot glue. " ' No. 3. An Iron Cement. — Manganese twenty- four parts, red lead five parts; formed into a paste with linseed oil. " ' No. 4. Cement for Fastening Iron and Stone. — Calcined plaster, iron filings and hot glue. The three following arc 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 HYDRAULIC LIMESTONE, filings, sixty-three of lime, one of magnesia, one of peal ash, and ten of charcoal. ' 3d, Thirty 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. " ' The china or diamond CL^ment, 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 1841, a patent for a lime cement was obtained by Kuhlman, who adds an alkali, like soda or potash, 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 Keese's and others, is nothing bat powdered oolite, a mineral lime deposit. Hame- lin's mastic cement, another very celebrated cement. CEMENTS, ETC. 79 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 golets, which are marly nodules of all sizes, like the septarias and marly concretions of other countries. A number of years ago, I prepared a good hydraulic cement 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. " ' Common Mortak. " ' Limestone, an im])ure 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 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 o^* 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 80 nYDKATJLIC LIMESTONE, consisting of two atoms of oxygen and one of silicon. Equal parts of fine and coarse sand are said to be better than either (Quality used separately with lime. Mortar designed for exterior or surface work is gene- rally made with fine sand. When lime is compara- tively free from impurities and crumbles to a fine 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-fluid 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. " ^ Htdraulic 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 bound together by it. The varieties of lime- stone from which hydraulic cement is made, when burned, yield a lime that is very slowly slaked. All that is required is to add w^ater until it attains the consistency of dough, it will then harden and become concrete. These hydraulic limes may be made arti- ficially by mixing with impure slaked lime a quantity CEMENTS, ETC, 81 of burnt clay in the proper proportions. The cele- brated Koman cement was a porous volcanic rock found at Puzzucli, near l^aples, and called there puz- zuolana. It consists of silicate of alumina, soda and lime. This substance is pulverized and mixed with common lime.' " The Silicate Hydkaulic Cement in the Pkeven- TiGN 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 by capillary attraction or otherwise, in the heart of the brick or stone work, the particulars of which have been lately described in the Manufactwrt d' Builder's Joui^nal^ 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 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- 82 HYDRAULIC LIMESTONE, tion with the ground, then the bricks, which ought to be specially prepared before calcination with a si- licate solution, should be heated over charcoal fur- naces and their beds dipped in the asphaltum before being laid. It is evident that a preventive course could thus be formed above ground at a trifling ex- pense, wholly impervious to wall-dam, at the same time giving a bedding to the superstructure of a qua- lity very far superior to any now in use. Coating the outside face of the walling w4th waterproof silicated cement, as has been before noticed, is only the safe- guard against capillary attraction from below, and excluding the external air which might let the artifi- cial heat of the rooms to attract the enemy of wall- damp. It is known that common brick will absorb 1-5 of its weight of water, and where the storm ' ^es the rain continually 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 ceil- ing, 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 wdiich 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 CEMENTS, ETC. 85 all the hydraulic properties and silicification, and caution should be taken in not using sea sand, which will certainly create the damp by absorbing all the water in tlie atmosphere, this being the chemical effect of its saline property. The surface of the walls of the rooms mnst be well attended to : the plaster of Paris, which is generally employed, ought to be properly silicified, so as ta prevent the absorbtion of the natural damp of the atmosphere created in uninhabited and unheated rooms. It is preferable to paint rooms than to paper them^ for the white lead and linseed oil, with a little lith- arge to facilitate the drying, becomes hard after a short time, and assists the fresh plaster wall of pre- venting the admission of the moisture; as the fourth coating of white lead is applied with equal propor- tions of oil and spirits of turpentine, which has the property of being very volatile, will evaporate en- tirely, leaving the surface of the paint of a very com- pact and hard nature, and rendering the plaster inca- pable of absorbtion. 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, and which does not crack in setting, and even of great usefulness as hydraulic cement under water, nYDEAULIC LEVIESTONE, is obtained by mixing finely slacked 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 ■quick lime, 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 one- eighth of the mass the liquid silicate of soda. One part of good slacked 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 applied to vegetable substances, decomposition is prevented, porous building stone and brick are pro- tected against air and damp. Damp Walls and Cellars. The application of silicates for preventing the penetration of rain or moisture in houses, whereby CEMENTS, ETC. 85 the walls are absorbing the same, and render the paper-hangings or delicate paint unfit, so as to de- stroy their appearance, has been amply and satisfac- torily proved. The silicates of soda and potash, or either of them, are mixed with pure white 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 the mortar, bricks or stone, which absorb and give out moisture, according to the changes of the wea- ther, or from damp foundations. The first only can be remedied 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 that a single applica- tion of a paint formed with lead or zinc has proved very successful. The second application is the sili- cate solution 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 paints must be put on uniformly, so that the whole wall . surface should be completely covered with the solid coat, and in order to efi'ect this a rough stucco surface, from two to three coats, may be required. It is found 4 86 HYDRAULIC LIMESTONE, also useful to apply tlie second coat tliinner 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 follow- ing manner ; Mix them with a little water and lay them on the stone, they w^ill 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 w^ash with an ordinary paint brush, stippling it so as to give it the appear- ance of the granulated surface of the stone. When dry it will adhere sufiiciently to allow of other washes of silicates being 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 wall wliich has been once painted is altogether unfit for any ap- plication of siliceous washes, for the reason that it is not absorbent enough. CEMENTS, ETC. 8f 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 may safely be applied in the sili- cate of soda for all the above purposes, and it will produce a good coating and a fine paint. Under the name of liquid stone, Fleury describes the application of the alkaline silicates in the follow- ing manner : " The first idea that suggests itself of the use of such a liquid is the preparation of artificial stories for ornamental and huUding pvrjmes. Should it be possible to produce this petrifying liquid clieap enough, buihling-stones in all their variety could be made and cemented together with the same jDctrify- ing solution. The cost of cast flint-marble statuary, tombstones, baths, tables, mantel-pices, and orna- ments of all kinds, would be, of course, much less than if laboriously cut from the stone, and they come quickly into universal use. In a similar way, as photography now diffuses the masterpieces of the art of painting among all classes of society, and cul- tivates their taste, the art of casting flint-marhle would multiply and difiuse the masterpieces of sculp- ture, and adorn our public buildings, gardens and parks. Bas-reliefs, cameos, cornices, columns, pillars, etc., might be produced at comparatively cheap 88 HYDRAULIC LIMESTONE, 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 flint-marble fronts, and our churches, halls, theatres, parlors and rooms with glass-lihe waU^, and ceilings, colored ad libitum with elegant frescoes as durable as the still fresh paintings at Herculaneum and Pompeii ; while the floors could be inlaid with beautifully colored stones in mosaic style. " Another important application for such a liquid would be the one to render wood non-inflaramdble^ rot and water-proof. By making wood non-inflam- mable, 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 solution of flint ; for, if once the pores of the wood, which by their capillary action cause the communication of the fire 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 silicificat!on 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, be- come more durable, and be, in addition, better non- conductors of electricity. What a new field would CEMENTS, ETC. fBUch a petrifying fluid open to the manufacture of incombustible paints and v^arnishes? It might also be mixed with paper pulp, or cheap vegetable or ani- mal fibre, and serve for the manufacture of a variety of useful articles, such as staircases, boxes, trunks, soles for boots and shoes, patterns, moulds, handles, parts of machinery, pliotographic instruments, piano- keys ; and, further- it might be used as a coating for preventing the oxidation of iron or other metals. We must not overlook another important application in the use of the liquid flint — the one for the preser- vation of old monuments and stone buildings. It might, perhaps, also serve as a medium for the pre- servation of meat, fruit, vegetables, eggs, etc. The linings of barrels, for oils and other liquids, the coating of tanks, tubs, sulphuric-acid chambers, etc., are other useful applications of this liquid. ''Metallurgy could be very materially benefited by a process whereby quartz could cheaply and 6pe3dily be dissolved in water ; for we could then take the gold quartz of Nova Scotia, New Hamp- shire, or Canada, 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 notliing, as the extraction price of the gold would be 90 HYDRAULIC LIMESTONE, 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 w^ater 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 i& 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 unlit 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- dispensable for this purpose. By an addition of an ^ilkaline silicate, either the silicate of potash or soda^ CEMENTS, ET(\ 91 and an addition of some alnmina, will, after burning, produce a good hydraulic cement, particularly in such localities where no good native hydraulic lime- stone is found. Not alone France and Germany are particularly rich in deposits of hydraulic lime, and in the United States likewise, Imt these in our neighbor- hood may be particularly mentioned at Kondout, on the western shore of the Hudson Eiver, 100 miles distant from New York. The quarrying in those subterranean rocks for hydraulic cement and also common limestone is carried on in that region, along a large extent of the valley of the Rosed ale River ; through this valley the Hudson and Delaware Canal is constructed, which brings the coal from the Lack- awanna valley at Carbondale directly to the Hudson River. This coal being a very pure anthracite is ad- mirably adapted for use in the limestone and cement furnaces situated at the junction of this canal with the Hudson River. 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 two powerful bases, and a silicate of lime and magnesia, as also silicate of alumina and aluminate of lime, are formed. The exact chemical reaction during the burning pro- HYDRAULIC LIMESTONE, cess is however as yet not well understood, and un- doubtedly varies in dilierent limestones, according to their chemical constitution, w^hich latter appears also to vary considerably, but without atfecting mate- rially their useful properties. In regard to the theoretical causes of the harden- ing process, which takes place under water, it may be remarked that this curious and interesting pheno- menon, being of an entirely chemical nature, has largely drawn towards itself the attention of eminent chemists, who have attempted to explain it in accord- ance with well known chemical laws. All hydraulic limestones may, by the ordinary method of analysis, be decomposed into tw^o 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, w^hich is a sili(;ate of alumina and potash, and a greater or less excess of free silica ; the latter consti- tuent is, therefore, simply a kind of clay. The reac- tion during the burning process has been already alluded to. Now when such freshly burnt cement is mixed with water, the excess of caustic lime as well the compound into which the siliceous clay has been converted during the burning, react upon one another in sncli a manner, that a solid stone-like silicate is CEMENTS. ETC. produced in the humid way, the water has a double action, dry substances, such as lime and silicate of alumina, do not act one upon another, unless the sol- vent 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 hydration in the silicate of lime as soon as formed. It must also be observed that the molecula'l^ 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 preci- pitated from a soluble glass solution by means of an acid, which produces the gelatinous form of silica, will at once combine with the lime in limewater and form a silicate of lime. The silica in the hydraulic mortar is also in a state, not like fine sand, but che- mically combined and dissolved in the mass, and therefore ready to combine with the lime in lime- water. Next in importance to silica is the magnesia, which renders the lime hydraulic, which, according to Fuch8, has been proved that lime and magnesia well mixed will harden under water to a certain ex- tent without tlie addition of silica; for' we have in GeiTnany a hydraulic lime containing only 4 per 94 HYDRAULIC LIMESTONE, 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 Rondout, usually called Rosendale cement, and witli the employment of which the Oroton Water Works of New York City were built, is the best on this continent. ^ It is confidently to be hoped that by the proper ap- plication of alkaline silicates will contribute much to the manufacture of an artificial hydraulic cement. Geeman Hydkaulic 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 useful 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 plas- tic by the liquid silicate of soda, at once applied as a CEMENTS, ETC. 95 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 chemial exami- nation of the ancient mortars from Burgh, Pevesney, and other Roman 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 :.ny time exerted a power of corroding the surfaces of sand, flint, pebbles, or even of burned clay, with w^iich it must have been in contact for long periods. Further, that the water originally combined with the lime has been entirely eliminated during this process of recarbonation ; and, this stage passed, the amor- phous carbonate of lime seems to have been gradu- ally transformed by the joint agency of water and carbonic acid into more or less perfectly crystallized deposits or concretions, by virtue of which its bind- ing properties must have been very considerably aug- mented. Messrs. Abel and Bloxam assign, as one of the causes of the hardening of mortars, the formation and subsequent crystallization of the carbonate of lime. Stinde proposes the silicate as a very useful ce- 96 HYDRAULIC LIMESTONE, ment by mixing equal parts of oxide of manganese and oxide of zinc, and making them into a thinnisli paste with the silicate of soda, which paste, quickly applied, sets very rapidly ; and by mixing the hy- draulic lime to this composition, it is a cement which will resist permanently also the action of water and heat : " Cement and Moetar of the Ancients. " We all know how enthusiastic some are in their j^raises of those ancient structures which have re- sisted 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 can not be denied that such critics are too partial in their admiration for things ancient as op- posed to things modern. We frequently hear the remark that some of the Roman mortars have en- dured for eighteen centuries 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 buildings constitute an ex- ceedingly small fraction of the enormous number of those erected during many centuries in Egypt, Greece, Rome, and her provinces. They do not consider that thousands of temples, palaces, and private dwellings have been entirely destroyed. And what answer can CEMENTS, KTG. 97 tkey assign to the faet that the very com plaints they indulge in were even more frequent then than now ? Pliny asserts that the reason of the falling in of many buildings in Home 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. He has left a work on Romai! architecture in which we find nothing that entitles us to place the architects of antiquity 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 Yitruvius both ex])lain, 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 witli the modern modus operandi. It is true that the old Tlomans were particularly careful in tlie selection of materials for their mortar, as well as in its prepa- ration. 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 whicli limestone undergoes in the process of calcina- tion, nor of that which is the cause of the cohesive quality of mortar. " Many centuries elapsed before these facts were 98 HYDRAULIC LIMESTONE, understood and explained. Black, in 1Y57, 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 Eomans ; and, in 1768, Lavoisier demonstrated the causes of the hardening 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. The white ones were con- sidered best, and the colored ones were seldom used. . Those taken from the interior of the earth w^ere pre- ferred to the stones which were met with upon the shores of rivers. A law provided that the lime must" have been slacked 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 has been established that a mortar can be prepared CEMENTS, ETC. that, in the course of one or two years, will be a& strong and durable as Roman mortar after the lapse of two thousand years. The builders of tjie ancients were not farther advanced than those of the middle ages. The walls of the Bastile, for instance, were so strong that they had to be blasted away. This iiad 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 tlieatre of the same city. " The Romans 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 Yitruvius : '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 Romans invaded the valleys of the Lower Rhine, they easily recognized the volcanic nature of the Brohl Yalley. Here, as well as amid 100 HYDBATTLIC LtM^^TONE, the surroundings of the beautiful Laacher Lake, which lies like a jewel set in the midst of the long- extinct Rhenish 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 understood. The solution of this problem was re- served for the investigating minds of the present pro- gressive century." " Hydraulic Cement. This material is justly esteemed far superior to metal of any description for the lining of cisterns, the water-proofing of cellar-bottoms, and similar pur- poses. 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 liard. JS^o mixture of these two varieties of lime can, there- fore, be made under water. But, although they do not act well together even under ground, they serve CfiMENTS, ETC. 101 well in dry places, such as buildings whose walls are of extra thickness ; and if proper care be taken, they will conjointly form a very compact 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 treatment 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 necessary when we consider the great difference which exists in the quality of both kinds of lime in various localities. 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 h firmest, and when thrown naked into the water 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 conse- quent action of the water will show, by its bubbles, the power of the lime. 102 HYDRAULIC LIMESTONE, " It is the per centage of clay contained in any spe- cimen of lime that determines 'the solidifying pro- perty of the cement made from it. The best hydrau- lic lime contains silex, lime and magnesia, or alumina. Its solidification is attributable to the formation 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 coiabines with water to form a solid hydrate ; which calcined plaster, from the large quantities of it man- ufactured near that city, is commonly known as Plaster of Paris. A limestone containing thirty per cent, of clay makes a quick-setting cement ; and we have in the United States the Rosendale and the Bellville cements, having forty and fifty per cent. They become exceedingly hard when plunged in water for from two to three minutes. Both these cements, especially the former, have been used ex- tensively 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 frit, which does not hydrate in contact with water. " As hydraulic lime is expensive, according to the CEMENTS, ETC. 105 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 forma- tion. It is prepared by stirring into water a mixture of one part of clay and four parts of chalk ; these materials should be mixed by a vertical wheel turn- ing 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 moderately calcined. Hydraulic lime thus prepared enlarges about two-thirds in volume when placed in water. Like the natural hydraulic lime, it can be completely dissolved by acids. This invention of artificial hydraulic lime has rendered Vicat deservedly famous, as it has been in use for many years in the public works throughout France, and was even employed in the hydraulic masonry of the St. Martin canal. That it can be made in this country there is no doubt, as the argillaceous or pot- ter's clay required is to be found almost everywhere^ The new cement which M. Sorel proposed to the French Academy consists in the application of a basic hyd rated oxycliloride of magnesium, may un- questionably be improved by means of a silicated hydraulic lime and the bittern of the salines, which 104 HYDRAULIC LIMESTONE, is a ehloride of magnesium in a concentrated con- dition. 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 combination with the constituents of either surface. Walls and piers have been built for over one hundred years, and after being exposed under water have be- come harder and harder. This cement is also called Eoman cement, because the natural materials are found in abundance in the Eoman district where the tufas, puzzuolanas and trass, all products of volcanic districts, like the Pontine Marshes of Rome, and near Naples, are abundant, and consist of those ele- mentary substances. In the volatic formations of the triassic period the marls or green sand, the cu- rious nodular and lenticular concretions, the Septa- rias and Indus Ilelmontii, 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 siliceous clay inter- mixed with lime, and are, therefore, the proper mate- rial for a hydraulic lime or cement; the Portland cement is largely manufactured at the mouth of the Thames, the Roman is also manufactured in England from the materials or nodules picked up or found in CEMENTS, ETC. 105 the cliffs near Harwich ; the septarias are from the London clay, and yield good cement. The marls of New Jersey, which are called green sand, occur in a large belt of cretaceous rocks, have of late years been of great importance to the Jersey farmers, and have a similar composition of lime, silica and clay forms, all excellent materials for a hydraulic cement. This cretaceous belt with its clay as a foundation and boundless supplies of silica forms the most pro- ductive strip of country and is well worth the con- sideration of a reflecting mind and the manufacturers of these substances. Most of tlie above materials contain about 70 procent Lime, 20 procent clay, and 20 procent silica, which when calcined, the Lime be- comes caustic and forms with the silica and clay a double silicate of this form such as CaO — CO3, SiO,, Al O3 H. O. The Portland cement is exported largely trom England and according to the manufacturers name is called Reess, Hamilton and other cements and will bear a strength varying from 20 — 60ft> to the square inch. The celebrated french cement of Bouilly is prepared in Boulogne from the pebbles called Golets which are nodules found in that region. The Terra Cotta is also a cement of clay and silica. Silicate of soda or potash may be mixed with the 106 HYDRAULIC LIMESTONE, particles of any material or body, sucli as common sand, dust, sawdust, clay, chalk, marble-dust, metal- filings, etc. ; a paste may be formed of the same, which, in a short time, will become hard and tena- €ious. Common clay thus mixed forms a fine and plastic mass, and becomes very hard. Saw-dust can be formed into any shape, acquires considerable strength combined with lightness, and has been pro- posed as an excellent non-conductor of heat. A €ake of the same five-eighths of an inch thick may be placed on a white-hot iron for half an hour, and while its under side in contact with the iron will get charred, the upper side will get but little warmed. The adhesion of all these various pastes to glass, minerals and metals is most remarkable, but, unfortu- nately, all of them except those formed with the carbonates of lime and some woods, do not resist humidity or water. However hard any article formed of sand, clay, etc., and silicate, may have become, however dry and old, the same is soon dis- solved or reduced to its component parts when com- ing into contact with water, or when exposed to humid air. The combination of the silicates with the carbon- ates of lime form a remarkable exception to the above. After the lapse of a comparatively short time, the objects formed of a paste of the same and silicate become hard and perfectly indissoluble in CEMENTS, ETC. lOT cold or hot water, and will resist humidity and weather. But their propert}^ to adhere to metals, more especially to iron, is so remarkable that the idea suggested itself to use the same as a coating for iron, either merely for ornamental })ur- poses, for protection against rust or fire, etc. A series of experiments and tests fully proved the prac- ticability of the process, and a patent was ap])lied for and granted to B. Oertly and X. Fendrich for the same. This coating of iron with marble and silicates, it may safely be said, constitutes one decided step for- ward in the use of silicates, and even of iron. While offering the most comprehensive protection to iron, the coating is susceptible of any coloring and of any finish of marble. Iron columns, espe- cially wrought-iron columns, can thus be rendered beautiful, while receiving additional security in cases of fire from the low power of conducting heat of the coating. Table plates, billiard plates, counter tops, doors or door-panels, shutters, etc., while vicing in appearance with stone, are rendered strong by their iron skeleton. In connection with saw-dust the coating forms the best coating for boilers and steam- pipes. As the co-efficient of contraction and expan- sion of the coating is almost identical with that of iron, exposure to heat and to great differences of temperature will not injure its sticking qualities. 108 HYDKADLIC LIMESTONE, and this singular quality of the coating really con- stitutes its excellence. The science of heating and ventilating public and private buildings has been extensively investigated and discussed for the last thirty years, and not with- out many practical and beneficial results. The me- chanical laws governing the subject, if no better understood than in the days of Peclet, are more generally hseded. The chemical constitution of fresh and pure air, of vitiated or contaminated air, has been ascertained by the most refined methods, in the valley, on the mountain, in town and coimtry, in the bed-room and public hall, almost all over the globe. An endless number of hot-air, hot-water, or steam-heating systems, of more or less or no value or merit, are at the choice of the wealthy, but no devices have until now been suggested to improve the means of heating the dwellings of the mass of the people. The iron stove forms as yet the great and simple apparatus for warming the inhabitants of the million, and from its cheapness, its portability, and its elastic adaptability to ditferences of tempera- ture of a wide range, continued to be the great means of heating the homes of the people. And indeed, if we are to believe the graphic accounts of a more recent lecturer and professional engineer of ventilation, (L. W. Leeds, Esq.,) it must also be re- garded as a providential protection of the people, CEMENTS, ETC. 109 that the introduction of those hot-air devices could not become more general. To correct or ameliorate the obvious defects of the iron stove by means at once cheap and easy appli- cable, is the object of the invention now brought to your notice. Acknowledging the great importance of ventilation, it is not proposed to interfere with that question, which moreover cannot be considered settled or ripe for a popular formula when such great discrepancies occur in the precepts of the most in- defatigable investigators, and when the air in the halls of Congress, though renewed twelve times an hour, and having a purer chemical constitution than the air of the Alps, is nevertheless considered op- pressive by our national legislators. The defects of the iron stove are well known — excessive heat one hour, deficiency of such the next hour, burning of the air, waste of fuel, etc. Per- haps nowhere are these defects more apparent, more oppressive, and more dangerous, than in the iron stoves of our railroad cars. Though many improve- ments have been made in iron stoves, it is certainly a patent fact that, in a great majority of cases, espe- cially during the severer portions of the winter season, the iron stove is allowed to become red-hot until the heat emanating from it does become unbearable and dangerous, when of a sudden the stove-door is thrown open and draft shut. The red-hot iron, being of a 5 110 HYDRAULIC LIMESTONE, temperature about 1,000^ F., decomposes or burns the organic particles, gas, or even animalcules, vdiich float in ordinary atmospheric air, to a greater or lesser extent, and which are exhaled from the human body. Air thus acted upon must become disagree- able and offensive, if not positively injurious. A serious waste of fuel does also take place by the above method of heating. The air of the room, when the stove-door is open, is heated over the burn- ing fuel, and escapes through the stove-pipe without contributing anything to heating the room, and the balance of the air, heated by the lower and hottest parts of the stove, follows the same line ; the draft being shut off or checked, but a small portion of air finds access to the heated coal, and on account of the great preponderance of incandescent carbon over the supply of oxygen, the combustion does not take place by producing carbonic acid C O, but by pro- ducing oxide of carbon C O ; a fact well established by chemists. This form of combustion, while con- suming the same amount of fuel, produces but one- quarter (^) of the caloric which is produced when carbonic acid C O is formed, that is, when a full supply of oxygen or fresh air is furnished to the burning fuel, as is the case with stove-door shut and draft open. The combustion is retarded, not as might be supposed, by spreading the same amount of caloric over a longer period of time, but by ac- CEMENTS, ETC. Ill tualiy reducing its measurable amount to one-quarter of that due to the consumed fuel when properly burned. Some of tlie oxide thus formed will find its way into the room, where its presence is by far more dangerous than a large amount of carbonic acid, it bsing a positively acting poison. The* stove now offered for the first time, and for which a patent w^as granted to B. Oertly and X. Fendrich, on the 18th of August, 1808, obviates or remedies the above defVcts in toto. It will be but a trifle more expensive than the common iron stove ; will be as portable as the latter ; will require as little extra mechanical skill in its setting and handling, while it substantially has all the advantages of the porcelain, the soap-stone, the sand-stone, etc., stoves, and excels them all in the finish it is susceptible of. The mass of silicate and minerals, either applied as coating to cast-iron or wrought-iron stoves, or forming exclusively the body of a stove, with or without an iron framework embedded in it for pur- poses of strength, radiates heat by far more freely than iron, while its conductive powers to that of iron are in the ratio of 16 to 27. Its superior radiating powers over those of iron can be readily tested and ascertained by any ordinary thermometer. It dif- fuses a pleasant and sufficient heat at a temperature at which iron scarcely makes itself felt, except by immediate contact, and thus allows of a sufficiently 112 HYDRAULIC LIMESTONE, rapid transmission of heat to warm an enclosed space without assuming itself such a high temperature as to burn or decompose any organic gases or particles floating in the air of any occupied room, and all of this while admitting the most favorable circum- stances for a full combustion of the fuel. Fresh air for ventilation can, and ouglit to be, introduced in the various manners it is now introduced in connec- tion with iron or porcelain stoves. The invention accomplishes, at less cost, all of what the most im- proved earth en w^ are or soap-stone stoves of the pre- sent day accomplish. Kuhlmann, in his theoretical view on the beha- viour of the alkaline silicate towards the artifi- cial production of hydraulic lime, cements and silicified stones, says of the artificial hydraulic lime as follows: If w^ater is mixed with slaked rich lime and a solution of a Potash or Soda silicate, the Potash or Soda are separated and the silica combines with the lime in place of a part of the water, which saturated the same and forms a paste, capable of disseminating in the fluid to all extend. This combination renders the lime plastic, which when exposed to heat and put into water, will keep clear. All particles of lime are 60 to say luted by the silica cement. This lime if combined with a basic silicate and exposed to atmospheric air, attracts, if in buildings, carbonic CEMENTS, ETC. 113 acid which by degrees is converted into silicate of lime. Similar products are obtained by substituting aluminates of these bases to the Potash or Soda sili- cates. The Sillification of the Mortar from Fat Lime. If walls are moistened with the solutions of the silicates, a reaction takes place at once to convert the hydrate of lime, no matter how old the same was, into a lime silicate, whereby a part of the Potash or Soda are separated ; the silicate which may have been bound to the carbonate of lime, forms a new com- bination analogous to that hydraulic mortar, produced artificially by the moist way. If the alkaline silicate is in excess, the reaction on the carbonate goes on according to the property described. The silification of porous limestones is explained in this manner : The native carbonate of lime, if coming in contact with the potash or soda silicate, acts partially like caustic lime. Potasli and soda are separated by the contact of the alkaline silicate, and the silica forms the same carbonated silicate, like that formed in the above manner. In support of this explanation must be stated, that the alkalis potash and soda are in all cases rendered caustic, and that the chalk must withdraw the last trace of the silica by the boiling it with the soluble 114 HYDRAULIC LIMESTONE, alkaline silicates, and invariably retaining the car- bonic acid in the composition. It is clear, there- fore, that the carbonates of lime exercise a basic effect in the presence of silica, which is retained by the potash or soda through some affinities. It is likewise obvious that these phenomena so indi- cate the invariable result of the formation of a hydrated silico carbonate of lime, which is capable of parting with its water by degrees, and to assume the characteristic hardness of hydraulic cements. The silification of gypsum is thus explained : The effect of the soluble silicates on gypsum, in plaster of Paris, is materially different from that which the silicates perform on lime. In a practical point of view, its results are unreliable and difficult to pro- duce. The alkaline silicates undergo a decompo- sition if coming in contact with sulphate of lime, they form a sulphate instead of a silicate. It is, however, known that sulphate of soda, on account of its crystalization, has a tendency of de- stroying the porous limestones, and it is therefore used to test the weather-worn stones ; it is advisable to use a potash salt if intended for hardening gypsum. Another important circumstance is in the application of the alkaline silicates on gypsum ; while the effect of the alkaline silicates on porous lime acts favorably for the hardening of the silica molecule, that of those bodies on gypsum is quick. CEMENTS, ETC. 115 almost instantaneous, which, when gypsum is brought in contact with the silica sohition, produces a raising or effervescing, giving great porosity to the gypsum, which scales off very soon, while weak silicate solu- tions produce more satisfactory results. For the purpose of possessing good results in plaster w^orks it is proposed an intricate mixture of 80 parts burnt and pulverized gypsum, 3 parts slaked lime, 10 parts powdered silicate in sufficient hot w^ater. All must be boiling. Cause of the Hardening of Hydraulic Cement. In order to test the truth of the different hypothe- ses made concerning this subject, A. Schulatschenke, seeing the impossibility of separating from a mixture of silicates each special combination thereof, re- peated Fuch's experiment, by separating the silica from one hundred parts of pure soluble silicate of potassa, and, after mixing it with fifty parts of lime, placing the mass under water, when it hardened rapidly. A similar mixture was submitted to a very high temperature, and in this case also a cement was made. As a third experiment, a similar mixture was heated till it was fused; after having been cooled and pulverized, the fused mass did not harden any more under water. Hence it follows that har- dening does take place in cement made by the wet as well as the dry process, and that the so-called 116 HYDRAULIC LIMESTONE, over-burned cement is inactive, in consequence of its particles having suffered a physical change. A Strong Cement for Iron. To 4-5 parts clay, dry and powdered, 2 parts iron filings, 1 part manganese, -J part salt, -J 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 Peasley Cement. The manufacturer of this cement has made him- self celebrated and wealthy by his perambulations throughout the United States with a span of horses attached to a load of hay, so it is thought advisable to enlighten 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- arabic, and 3 parts of gum traganth, and to this solution an alcoholic solution of white shellac ; 1 part of the latter is then mixed with the watery solu- tion. To the wdiole 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, 24^ parts lead, 12 parts glycerine, 200 parts alcohol, 50 parts isinglass, 3 parts gum arable, 3 parts gum traganth, 1 part bleached shellac. CEMENTS, ETC. 117 The Sir.TCATTON of Fresco Painting. The same phenomena attending those of mortar take place in fresco painting. It is known that the colors prepared by water on the rough mortar of fat lime and sand are fixed by the. carbonate of lime which envelopes them, appearing dull in many re- spects, of an agreeable appearance, as has been demonstrated in the durability of the old paintings of Herculaneum and Pompeii, which have been overthrown by rains of ashes 79 years after Christ, and were buried in a depth of 100 feet. By moist- ening with the liquid silicates the walls so painted, the surfaces of the rough mortar of fat lime assume the properties of hydraulic cement and acquire hardness. Silicate Painting by Means of a Brush. The colors rubbed up with a silicate produce an intimate combination of the carbonated salts and acids, and the alkaline of the silicates are separated thereby. If the color is composed of a material un- susceptible for a chemical affinity, a silicate mass is formed by the action of the atmospheric carbonic acid, which makes an extraordinary binding cement, and by the separation of the alkali assumes a perfect insolubility in a very short time. This operation is accelerated if a coating of gypsum has been laid on * 118 HYDRAULIC LIMESTONE, the lime, and becomes more solid and intimate, because the alkaline and silicate acts at the same time on the coloring and carbonate of lime ; in which case it is very serviceable to moisten the wall before applying the colors with a weak solution of liquid silica, in order to prevent the too rapid with- drawal of the silicate and cement from the colors. Injection of Silicates. While engaged in impregnating the soluble sili- cates into the porous stones, and carrying this opera- tion into all organic and inorganic matter, the con- vincing proof was manifested that the hardening of those bodies are only owing to the decomposition of the silicates, effected by the slow action of the atmos- pheric carbonic acid and the gradual condensation of silica. This phenomena led to the observations that the natural silicates and aluminates, 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 crystallized minerals found in limestone formations, but also an endless variety of silicated and all urn i- nated substances found in nature, owe their exist- ence to analagous causes; that the flints, agates, and * petrifled wood cannot have any other origin, but that CEMENTS, ETC. 119 they are formed by the slow decomposition of a sili- cated alkali from the carbonic acid, either atmos- pheric or generated during the process. This fact is of the highest interest in the chemico- physical investigations, and is the key to tlie investi- gations of the formation of the natural silicates, even under many various circumstances, of the conden- sation of silica by other bodies than the carbonic .acid ; many experiments undertaken have proved the gradual 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 concentration of the original decomposed ma- terials. The iridescence of the opal, which disap- pears if exposed long to dry atmosy)here, 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 alkaline silicates by the lime, and this may be proved by the formation of saltpeter or nitrate of potash in the ^fflorescenses 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 oxidation and conver- 120 HYDRAULIC LIMESTONE, sion into nitric acid, and at once is combined witli the alkalies contained in the native lime occurring in the older formations, and was separated, nndef certain circumstances, from the alkaline silicates found in those limestones, 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 there localities abundantly in certain soils of Spain, Egypt, Persia, and E. In-dies, 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 nitraries are arranged for this purpose in many countries. Refuse animal matter also, putri- fied in calcareous soils, gives rise to nitrate of lime, as w^e find it so frequently in cow and horse stables, and is then converted into nitrate of potash ; old plaster walls, when lixiviated, afford about 5 ^ of nitre. It is known that nitre requires for its forma- tion 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 oxidation of the nitrogen of the air is promoted by organic matters, hence the nitre is generally associated with azotized decomposed organic substances. A nitre crust from the vicinity of Constantine, Algeria, CEMENTS, ETC. 121 afforded Boiissingault S6% nitrate of potash, with some nitrates of lime, soda and magnesia. In the Mammoth cave of Kentucky, where the nitre is found scattered throngh the loose earth in great abundance, and was utilized during the war of 1812, also in the Mississippi Yalley, in Missouri, many caves have yielded the nitre which was of great use to the secessionists of the late war, when Tennessee^ along the limestone slopes and in the gorges of the Cumberland table hind, produced a large amount of saltpeter. The nitrate of soda, formed in a similar manner like that of nitrate of potash, but more ])articiilarly found in the dry pampas of Chili, where it is found at a height of 3,300 feet above the sea, and 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. Kulilman has proved by his investigations that the larger number of limestones from various geo- logical 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 efflorescense of the carbonates of potash, chlor- ides of potassium and sodiums, which make their appearance on the surface of walls from their con- struction, to which he was led by the fact that the alkaline salts in general are obtained in larger quan- 122 HYDRAULIC LIMESTONE, titles from hydraulic limes than from the lixiviation of air limes, and that the hydraulic limes contain mostly more alkali, and that it exerts much influ- ence upon the quality of lime, and it has been ascer- tained by Yicat that the occurrence of the potash and soda is neither accidental nor less influential upon the proportion of the hydraulic limes. It is presumed that the silicated limestone, and any fat lime mixed with clay by the influence of potash or soda are during the burning converted into double compounds*, analagous to the natural silicates, which are known under the name of zeolites, such as meso- type, stilbite, apophyllite, etc., which all form hy- drates, and lose their water of crystallization by burning, and absorb it again on moistening ; one of the species of that class of mineral, such as the laumonite wliich, when exposed for some time to the atmosphere, eflloresces and crumbles to piec^ to the chagrin of the mineral collectors, but it is suiiicient to confirm the remark just made regarding their con- stitution and similarity of the artiflcial silicates of lime and alumina. It is apparent that, in the hard- ening of hydraulic lime a process takes place anala- gous to that of gypsum when hardening, and forming a hydrate. It may, however, be possible that the hydraulic limes be still formed without the presence of potash or soda, and that the silicium or aluminium in contact with lime fills the same oflice in possessing CEMENTS. ETC. 123 the property of binding the water, and to convert them in certain conditions to a hydrate. Respect- ing the cement which is formed by the moist 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 cor- corresponding quantity of potash in carbonate of potash : this explains the true artificial stone which has become, on exposure to the atmosphere so hard, that, if the mixture contains a sufficient quan- tity of a silicate, possesses 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 analagous to cements without burning, and may be used for restoring monuments, etc. In the sillification of artificial stones the affinity of lime to . the silica contained in the soluble glass is manifest, and shows the effect of the alkaline sili- cates on limestones; and how the influence of the atmosphere in the hardening of silicates or artificial limes is brought to bear through the atmospheric carbonic acid by the separation of one part of silica in the silicates, and how the other parts of the sili- cate, 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- 124 HYDEAULIC LIMESTONE, iicial impregnation of mineral substances into the interior of porous substances organic as well as inor- ganic matters are preserved, or silicified. The sili- fication of a fine sandstone is easily effected bj 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 ex- posed to the atmosphere for some time, and the finishing process continued by means of hydraulic pressure and heating in hot chambers, the particulars of which have been indicated in a former chapter. It has been ascertained that always if any salt in- soluble in water is brought in contact with the solu- tion of a salt which forms witli the acid of the base of the insoluble salt, a less soluble substance, an exchange takes place, which, although but partial sometimes, produces the formation 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 use of the brush in the application of colors- has so far been but partially accomplished. The substitution of the potash or soda silicate for the fixed and volatile oils with mineral colors has at first been attempted by 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 contact 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 decomposition, 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 solution. It appears that this baryta may be used with more advantage by itself, as it unites perfectly with the silica and appears to form a chemical compound, but a disadvantage presents itself in forming but a half transparent color, which does not cover well, and the addition of oxide of zinc is therefore recommended^ which agrees well with the paint in connection witb baryta and silica ; this application has produced very 126 SILICATE PAINTING ON STONE. satisfactory results, forming a cheap white paint, which can be easily transferred with a brush. Many mineral colors, mixed with white bases, pro- 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 combina- tions retain the alkali obstinately, and it was at- tended with many difficulties to apply the colors with the liquid silica, yellow ochre, bine and green ultramarine,, sulphuret of cadium, manganese per- oxide 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 silifi- •cation of the wall is indispensable on the painted <3oloring, which is done by preparing, as usual, with the liquid silica, as other paints are treated. The «oda silicate used for painting on walls is easily -effected by the use of the syringe. The painting on walls is attended with some difficulty likewise, for w^hile 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 their physical SILICATE PAINTING ON STONE. 12Y appearance, becomino; darker ; oakwood assumes the appearance of an old wood, and only the white and hard woods, such as the ash and maple woods, will take up the silicate painting. Another difficulty takes place in painting on wood, that it peels off, if applied too thickly. A weak solution of 1 part silica, of 28° B to 5 parts water, either alone or combined with other bodies, is recommended. For protecting shingles against rot, or rendering them incombustible, 4-5 applications,, during an interval of a day each, may be made, and another method is to season them, first by steam, then soak- ing them in green vitriol solution, and then impreg- nating with silica, quite hot, and at last to throw fine sifted sand upon them. Wooden stables, and other buildings exposed to vapors or great change of temperature, three or four coatings of the silica solu- tion is recommended. Further Remarus on Stereo-chromic. Tliis new art of painting derives its name from two Greek words arepeoff^ fast, or permanent, and from jpcy/^^^j the color, and has been introduced as a substitute for fresco painting, and bids fair to be very extensively applied, and more than the en- caustic 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 128 SILICATE PAINTING ON STONE, painted by Kaulbach with panels 21 feet high and 24f feet broad, and are said to equal the oil paint- ings in freshness and vigor, and with that particular advantage that the paintings may be viewed or ex- amined 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 materially 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 ma}^ 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 to a paste and laid on the wall. The surface is made even by an instrument, and the upper layer removed which was formed on coming in contact with the air ; but the mass must be always kept moist during the whole operation. This rough mor- ter will soon become dry, and may be rubbed off" SILICATE PAINTING ON STONE. 129 with the fingers, but it must not be left too long ex- posed to the air for fear of its attracting the carbonic acid, whereby the lime would be too much carbon- ized. By the application of a solution of carbonate of ammonia 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 penetrate into the morter, and the liquid glass ought to be that made from soda, and quite clear, that liquid soluble glass which was used at the Munich Theatre consisted of silica 23-21, soda 8- 20, and potash 2-52, and had a specific gravity of 1,381, and was then diluted by an equal quantity of water. In all cases, the liquid must be laid on by means of a brush, in order to produce a uniform im- pregnation of the same. When this 'groundwork, called the underground, is faithfully and carefully prepared, the upper groundwork which is to receive the painting may be commenced with ; it does not ditfer much from the first operation. The sand to be used must be of fine grain, and well washed, as also the quartz, etc., (tlie 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 130 SILICATE PAT^JTING ON STONE. other substances before the application of the fine sand, in ord-er to destroy any lime crust which might have been formed in the preparation of underground, and diluted phosphoric 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 diluted also with equal quantities of water, which is done twice, allowing sufiicient time to dry between each impregnation. VYood 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 overcome, 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 <3olor was thereby obtained, but chlorate of potash remained in this operation, 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 destroy- SILICATE PAINTING ON STONE. 131 iiig them ; the perchloric and hydrofluoric acids were resorted to. It is well known that by washing with hydrofluoric acid the density of the colors is much increased, and it was thought therefore sale to use it^ particularly in painting on glass, but only as a very weak solution. Hydrofluoric acid possesses the most remarkable property to dissolve 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 siliflcation of limestone^ was mainly calculated for such case where a silicate has been used with an excess of potash, and in hard- ening of soft and porous limestones by a partial con- version into a lime silicate it was found very expe- dient for fixing the potash, and making sure the in-^ solubility 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, pene- trated the stone and produces an insoluble com- pound, in other words, it fixes the soluble potash, and produces an insoluble compound. Through thia discovery 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 132 8ILICATE PAINTING ON STONE. bydrofluoric acid, and so miicli 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 l)ut slowly, and it is therefore simply a fluorsilication that produces the hardening of the lime. The effect of the hydrofluoric acid on gypsum is also produced in a cold mixing of both, when the surface of the gypsum is considerably hardened. If, however, the acid is used in excess, the gypsum is covered with raised postules, which owe their existence to the for- mation of bisulphate of lime, because sulphuric acid •does not act as well as the carbonic acid in the treatment of limestone; a fluorcalcium, mixed with soluble glass, may be used as a paint, or paste, or a • cement, or any coating of other substances, and be- comes so hard and weatherproof that neither soda nor potash will detach from the combination and remain dry. 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 afl'ord much induce- SILICATE PAINTING ON STONE. 133 iiient for its use. - The sulphate of baryta, aTtificially prepared, combined with potash silicate, appled to glass, makes a milky white appearance, and is very beautiful, as it incorporates 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 oxyde of tin, and is much cheaper. Ultramarine, oxide of chrome, if con- verted into enamels, form a prolific source for the new art of painting. It is not quite necessary that a cliemical combination should be produced in all these colors, if they only adhere strongly and pro- duce 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 extra- ordinary hardness, resisting the effect of heat com- pletely, 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 hik is prepared by decomposing leather in 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 6 134 SILICATE PAINTING ON STONE. ink, resisting completely the action of chlorine and all other acids. The alkaline salts, particularly the carbonates and chlorides, produce, when added to liquid silica, a gelatinous pasty precipitate, the chloride of am- monium with developing the ammonia; precipitates are also formed with the earthy alkaline salts, and from alumina and hydrate of lime, for in all these cases of precipitations a part of potash is withdrawn from the soluble glass, which either forms a part of the precipitate or remains free, or attaches itself to the acid of the added salt. The same case takes place in the application of the salts of the heavy metals, such as iron, copper, etc. The effect of tlie soluble glass on salts, either insoluble or soluble with difficulty in water, such as sulphate of potash and carbonate of lead, phosphate of alumina, gypsum, etc., all of which become, when rubbed up with the silica solution and exposed to the air, a very hard mass. The fixation of potash with silica painting on lime shows how the colors, after an exposure to air for some time, become quite insoluble in water, and is thus explained : The contact of carbonate of lime with the soluble glass determines always the decom- position of the first, and conversion in silicate of lime, which retains the coloring matter. If the colors are transferred on substances not acting upon SILICATE PAINTING ON STONE. 135 the soluble silicates like wood, iron, glass, etc., then it becomes necessary to find the conditions of the insolubility in the reaction of the coloring matter in the silicate itself. Much precaution has to be used not to close the pores of the underground, whereby the success of the painting is jeopardised, in case a mistake should have occurred before, and by waiting some time be- fore proceeding farther, to allow the contraction of the liquid glass, so as -to open again the pores, and which can also be accelerated by heat that is pro- duced by burning alcohol over the groundwork. Now, after this operation of drying and prei>aring is performed, and the liquid glass applied uniformly, so that every paint is found uniform so as to begin the painting, the artist will have no difficulty to begin at the proper work. The colors are now per- fectly rubbed up with the water and put on artisti- cally after the wall has been syringed with pure water — for two reasons : one is to expel the air from the pores, and then to promote the adhesion of the colors ; this, however, must be done moderately, or the colors might otherwise suffer in freshness ; the moistening must be effected on every spot which has to be painted. The colors are now prepared with the liquid glass, diluted with one-half of its water, which must be applied by means of a syringe, and not by a brush, and with much care, for the reason 136 SILICATE PAINTING ON STONE. that these colors adhere but thinly, and, if applied with the least force, would put the colors from their place, or would make them flow together ; the opera- tion of syringing over, the painting must be repeated several times after having become dry, until the colors appear to be so fast that, touching with the fingers, they will not be stained. Many colors re- quire more or less of the liquid glass, which may be learnt by practice, but which may easily be detected. When the painting is finished, an application of alcohol, after the lapse of a few days, will materially add to fasten the painting and to clear it from any impurities which may have atta(;hed themselves, or by the alkali which might have been separated from the liquid glass and have oozed out, and may be worked with mortar free from lime, and it may thus, without any hesitation, be left exposed. It may be observed that the painting must be guarded against rains during the time of the rub- bing up and laying on of the colors. After the ex- posure of some months, or a year at latest, it is well to examine the painting, in order to ascertain whether the colors have not suffered from rhe con- densation of the^ liquid glass, so as to produce an interruption of the binding or fastening of the colors, so that it may become necessary to apply an ad- ditional fixation. The materials for the upper ground, which is to SILICATE PAINTING ON STONE. 137 take up the colors, may be also composed of the fol- lowing: Pulverized marble, dolomite, slaked lime, and fine quartz, or a sand with the liquid glass com- bined; the proportion of the liquid glass depends upon the sand which is used in the mixture, so as to form the consistency of mortar. The advantages of this ground work are : it prevents the separation of the lime on the surface after a frequent moistening with water, and, therefore, no lime crust forming, no rubbing off is required before the application of the liquid glass; furthermore, the liquid glass comes in immediate contact with the under ground, producing thereby a good cement with both grounds. This mortar becomes as liard as stone after being dry, and shows its porosity in warm and dry air, which make it very susceptible for absorption. Stereocuromic for Easel Painting. The basis for this class of painting may be made from plates of burnt, porous clay ; it is first im- pregnated sufficiently with liquid soda glass. These plates may be f 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 paint- ing ; a thin coating of liquid glass mortar will pro- duce a good base, and it may be first moistened with 138 SILICATE PAINTING ON STONE. 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 hot 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, vermillion 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. The permanent white, or artificial sulphate of baryta, 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 efi*ected by the reduction of the native sul- phate to a chloride of barium, or dissolving the native witherite in hydrochloric acid, and then ad- ding either sulphuric acid or glaubersalt, the arti- ficial sulphate of baryta is found in a condition of extreme fineness and purity, possessing a fine lustre. SILICATE PAINTING ON STONE. 139 and suscsptible for producing a fine white paint, which is the b3st substitute for white lead and zinc white, is not subject to tarnish or become brown in parlors like white lead, which is attacked by hydro- sulphuric acid, and forms, when combined with the liquid glass, a slow but intimate combination, and is likewise used under the name of blanctix for card- makers, paper-stainers and paper collar manufacturers to a very large extent. It may also be considered in point Of importance^ if compared with that of white lead, not having a dilatory effect upon health as the latter. If mixed with the soluble glass it obvi- ates the odious smell of linseed oil and spirits of tur- pentine. If it is mixed with dexterine, starch, or other binding material in connection with the liquid sili- cate of soda, its applications may be multiplied to any extent. The artificial sulphate of baryta is largely manu- factured on the continent of Europe ; in the U. S. it has so far bean manufactured in New York by a few chemical establishments for card makers, but not yet for the purpose of substituting it to white lead. SILIFICATION OF WOOD A Protection against Combustion, Inflammabil- ity 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, expe- rience, 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 conflagration by the impregnation or coating of combustible bodies with many sub- stances, such as possess incombustibility, whether liquids, gases, or materials which possess the proper- ties of generating gases that will withdraw or sufib- cate 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 form, and many metallic salts have proved but a par- SILIFICATION OF WOOD. 141 tial 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 material w^as recommended in the construction of the Munich Theatre, where 465,000 square feet of timber surface were treated with a coating of the liquid soluble glass, and in 1830,-31 and '32 the author performed many experiments in the Brooklyn Navy Yard, par- tially as a protecting agent against fire, as also against decay of the w^oody fibre ; small square blocks of wood, after having been impregnated with the soluble glass and sailcloth, writing paper, parch- ment, etc., were exposed for some time to the flame of a gas lam]). After the lapse of an liour, all these substances were found to be charred, but not con- sumed. It is proved that the liquid soluble glass produces a perfect adhering, permanent covering which, when properly laid on, suflers no damage from the atmosphere. For coating the wood, etc., a pure solution of tlie liquid glass is required, other- wise it will peel ofl', and it is best not to use it first in a concentrated state, as it will not be able to pene- trate 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 pulverized substances, wherein 142 SILTFICATION OF WOOD. the soluble glass acts as the binding material, the coat- ing assumes a better body, is stronger and more per- manent, 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 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 re- sorted to in order to produce a full absorption with the pores ; these stuffs may then be rolled up, but not folded. Building timber, rail road sleepers, and other sim- ilar 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 pro- ducing in the cells of the vegetable fibre the various mineral and metallic salts which are altogether in- soluble in water, alkalies and acids, and he extended his experiments on the uses of lime, chalk, gypsum, copperas, 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 SILIFICATION OF WOOD. 143 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 woods 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 gypsum, finely powdered and thrown into hot water, or finely powdered chalk of 1 ft), to 10 gallons of water: the proportion of metallic salts is but J fb. to the gallon of water. The woods are kept in the vats for another day, and then taken out dried and ready for use. Coal tar, and the other products of dry distilla- tion from tar and peat, have been recommended by Krieg as far back as 1858, under the name of Kreo- sote-carbolic acid, which was then considered a waste product, and in its raw state having a spec, grav. of 1.02 to 1.058, and yielded from 20 to 30 % of the tar, it was well known to possess the property of protecting wood against decay. This chemist combined with the impregnation of woods, etc., the soluble glass that of the kreosote car- 144 SILIFICATION OF WOOD. bolic acid for the reason that the latter precipitates the soluble silica as an insoluble substance while it is soluble in an alkaline Ije. He proposed to expose the woods for f of an hour to a temperature of 300° p F., and then drying them thoroughly. The woods thus prepared showed an increased weight of 6 and a lacquered surface, while in the inside the pores were filled with an insoluble precipi- tated silica. For effecting a still more perfect success is to fix the kreosot on the woody fibre from the alkaline so- lution, by the 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, and the creosot-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 attention of the various companies established for the last five years in the preservation of wood by carbolic acid, tar, etc., by combining the soluble glass with their process, as we have described. Since the introduction of railroads, not quite 60 years, many men have been engaged in chemical experiments upon the cross ties and sleepers, which after being laid dawn for a few years undergo the decay or rot and have to be renewed, which causes SILIFICATION OF WOOD. 145 great expenses to the companies. Kyan, Burnett, Boucherie and many other chemists in all .coun- tries where this evil existed, proposed remedies ; the sublimate, chloride of zinc, pyrolignite of iron, all had their advantages and disadvantages; of late borax, alum, rosin, carbolic acid have been in- troduced and many articles have been written on the subject. Preservation of Wood, in Damp and Wet Places. In 1846, 80,000 sleepers of the most perishable woods, impregnated, by Boucherie's process, with sulphate of copper, were laid down on French rail- ways : after nine years exposure, they were found as perfect as when laid. We would suggest washing out the sap with water, which would not coagulate its albumen : the solution would appropriately fol- low. Both of the last named processes are compara- tively cheap ; it costs less than creosoting, but one shilling per sleeper. The unpleasant odor of creosote is greatly against its use for lumber for dwellings ; pyrolignite of iron is offensive, and also highly in- flammable; the affinity of the chlorides for water keeps the structure into which they are introduced, wet, and they also corrode the iron-work. Sulphate of copper is free from these objections, and is cheaper than the chlorides, and seems preferable for protect- ing wooden structures against dry rot in damp situa- 146 SILIFICATION OF WOOD. tions, like mines, vaults, and the basements of build- ings. The surface of all timber exposed to alternations of wetness and dryness gradually wastes away, becoming dark colored or black. This is really a slow combus- tion, but is commonly called wet rot, or simply rot. Other conditions being the same, the most dense and resinous woods longest resist decomposition. Hence the superior durability of the heart wood, in which the pores have been partly filled with lignin, over open sap wood ; and of dense oak and lignum vitae over light popular and willow. Density and resinousness exclude water ; therefore our preservatives should in- crease those qualities in the timber. Fixed oils fill up the pores and increase the density ; the essential oils resinify, and furnish an impermeable coating ; but pitch or dead oil possesses advantages over all known substances for the protection of wood against changes of humidity. According to Professor Lethehy (" Civil Engineers' Journal," vol. 33), dead oil, 1st, coagulates albuminous substances; 2d, absorbs and appropriates the oxygen in the pores, and so protects from eremacausis ; 3d, resinifies in the pores of the wood, and thus shuts out both air and moisture ; and 4th, acts as a poison to lower forms of animal and vegetable life, and so protects the wood from all para- sities. These properties specially fit it for impregnat- ing timber exposed to alternations of wet and dry SILIFICATION OF WOOD. 147 states, as, indeed, some of them do for situations con- stantly damp and wet. Dead oil is distilled from coal tar, of which it constitutes about 30 ^ cent, and boils between 300^ to 470° Fahr. Its antiseptic quality re- sides in the creosote it contains. One of the compon- ents of the latter, carbolic acid, (phenic acid, phenol) Q12 Q2^ ^Yie most powerful antiseptic known, is able at once to arrest the decay of every kind of organic matter. Professor Letheby estimates this acid at one half to six per cent, of the oil. Bethell's process sub- jects the timber and dead oil, enclosed in large iron tanks, to a pressure varying from one hundred to two hundred pounds per square inch, about twelve hours : from eight to twelve pounds of oil are thus injected into each cubic foot of wood. Lumber thus prepared is not attected by exposure to air and water, and re- quires no painting. Four pence the cubic foot is estimated as the probable expense of this process. Though we have not to guard against decay, when timber is constantly wet in salt water, the Toredo- navalis^ a mollusk of the family Tuhicolaria (Lam.) soon reduces to ruin any unprotected submarine con- struction of common woods. Kone of our native timbers are exempt from these inroads. The toledo never perforates below the surface of the sea-bottom, and probably does this little injury below low-water mark ; its food is the borings of the wood. Poisoning the timber does not protect from the toledo, the con- 148 SILIFICATION OF WOOD. stant motion of sea-water soon diluting and washing away the small quantity of soluble poison with which the wood has been injeted. Thorough creosoting the wood, with ten pounds of dead oil per cubic foot, is a complete protection against the toledo. Drying Timber by Steam. Mr. Yiolitter has lately presented to the Academy of Sciences in Paris, a very able communication on the desiccation or drying of different kinds of wood by steam. He states that steam raised to 482°, Fah- renheit, is capable of taking up a considerable quan- tity of water ; and acting upon this knowledge, he submitted difierent kinds of oak, elm, pine, and wal- nut, about eight inches long and half an inch square, to a current of steam at seven and a half pounds pres- sure to the square inch, but which was afterwards raised to 482^. The wood was exposed thus for two hours. It was weighed before it was exposed to the steam, and afterward put into close-stoppered bottles until cool, when the samples were again weighed, and showed a considerable loss of weight, the loss of which increased with the increase of the temperature of the steam. For elm and oak the decrease in weight was one-half, ash and walnut two-fifths, and pine one-third. The woods underwent a change of color as the heat was rising from 395*^ to 442'^ ; the walnut became very dark, showing a kind of tar formed in SILIFICATION OF WOOD. 149 the wood- by the process, which was found to have a preserving effect on the wood. It was found that wood thus heated became stronger, having an increase in the power of resisting fracture. The maximum heat for producing the best fracture- resisting power for elm was between 302 and 34Y^, and between 257 and 303 degrees for the oak, walnut, and pine. The oak was increased in strength five- ninths, wahiut one-half, two-fifths for pine, and more than one-fifth for elm. These are but preliminary experiments, which may lead to very important re- sults, and are, therefore, interesting to architects especially. By this process the fibres of the wood are drawn closer together, and maple and pine treated in the steam, at a temperature of 487°, were rendered far more valuable for musical instruments than by any other process heretofore known. This is valuable information to all musical instrument makers. Who knows but this is a discovery of the Venetian fiddle-makers' great secret. Wooden Roof Shingles. One of the most valuable applications of the soluble glass may be recommended for shingles and wooden roofs of farmhouses in the country and near railroads, where the sparks of the locomotives have frequently caused deflagrations and destruction of property. The operation is quite simple and the expense but 150 SILIFICATION OF WOOD. trifling ; the process has already been described, but it may be still more simplified in the following man- ner : 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 aweak solution of liquid silica, standing about 25° B, in which they are left for 24 hours, when they are taken out and exposed to the air. Before they are quite dry, a weak solu- tion of chloride of calcium 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 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 inflamation. The Preservation of Wood by Immp:esion. The processes for the preservation of wood may be divided into three groups, namely : processes by immersion ; 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- SILIFICATION OF WOOD. 151 pregnate wood with alum, sulphate of iron, and various other substances, in solutions of which he im- mersed it for several day. In 1Y56, Haller recom- mended vegetable oil for the same purpose. In 176 7, Jackson indicated the use of a solution of sea sale, 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. Not long since, experiments were made in France and Ger- many with a large number of railroad ties, by keep- ing them several hours in a solution containing 1.5 per cent, of sulphate of copper, at a temperature of 160*^ Fahr. This preparation is, however, altogether insufficient for the preservation of fir or pine wood, and in general for light woods which contain a large amount of nitrogenous substances ; but it seems to increase considerably the durability of oak. The wood is thus surrounded 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 impregnated at all by the anticseptic liquid ; they preserve their germs of putrefaction, which develop the easier the more the injected surface is removed, whether by friction 152 SILIFICATION OF WOOD. blows, or the driving in of nails. The decay com- mences then at the denuded points, and propogates itself tow^ard the central parts. Baron Champtj also indicated a method for pre- serving wood, by dipping it when green into suet of 200" Fahr, The water and the gases which are in- closed in the vegetable tissue escape, and by the con- densation which follows upon cooling, a vacuum is produced, into which, by the pressure of the atmo- sphere, the suet is made to penetrate. Mr. Pay en made use of this experience, substituting for the suet, rosin, heated to 300" Fahr., and in this manner in- troduced into a small poplar tree three-fifths of its weight of rosin. Decay of W ood 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 ex- clusively caused by the action of air and water. On exposing 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 disen- gaged. It is now conceded that it is the hydrogen of the fibre which is oxidized 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 8ILIFICATI0N OF WOOD. 153 the carbon of tlie wood by direct oxidation ; and it would seem, from the experiment mentioned, that the first and only 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 degrees. 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 woody 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 afterward dried until the original weight is restored, it is rendered therby 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 closely resembles both in properties and composition, t 154 SILIFICATION OF WOOD. the vegetable albumen is exceedingly liable to decom- position. In this state, it acts like a ferment, induc- ing the decay of other bodies, according to the phy- sical law propounded in another application by Lap- lace and Berthollet, namely, that a molecule set in motion by any power can impart its own motion to another 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 solu- tion of caustic alkali — this soda, or potassa — which has no action on the woody fibre, but only dissolves SILIFICATION OF WOOD. 155 the albumen. Hence, the quantity of the latter may be estimated by washing, drying, and weighing the wood after the experiment has been made. Methods of Preserving. Wood. If the primary cause of the decay of woody libre be its contact with putrefying albumen, a means of preserving is naturally suggested in the removal of the albumen ; or else in so combining it with other substances that it forms a compound which is insol- uble in water, and not susceptible to spontaneous decomposition. It would seem that the solubility of the albumen in cold and tepid water would afford a simple means of withdrawing this clement of decom- position, and thus of preserving timber ; but this pro- cess, though effectual, is by far too slow to be practi- cable. The most ancient method of guarding wood against decay consists in the application of an external coat- ing of oils and resins or a hot solution of silicate of soda, according to the author of this treatise in connection with that of chloride of calcium and carbolic acid. If tlio wood is dry, and otherwise in a sound state, and also not exposed to abra- sion, a perfect protection may be afforded in this way. A more elFectual mode of preserving it, how^- ever, consists in its immersion in a hot solution of the respective preservative. This may either serve 156 SILinCATION OF WOOD. simply for filling the pores, or for forming a com- pound with the albuminous matters, which has the property of not being decomposed. Both ends may be arrived at by one and the same substance. Impregnation of Wood by Pressure. This method was not practiced to any great extent previous to the close of the last century. In the in- quiry into the means which have been taken to pre- serve the British navy, particularly from dry rot, a volume has been produced, which affords a splendid account of all that had been done up to that time in the direction of wood preservation. The author gives a full account of the action of about forty sub- stances, among which may be mentioned, solutions of sulphate of copper, sulphate of iron, alum, borax, lime, corrosive sublimate, and other forms of mercury, preparations of zinc and iron, sea-salt, creosote, lin- seed-oil, coal and wood tar, and wax. As it is how- ever, not the intention of these articles 'to do dwell upon things of the past, but upon things of the pre- sent, the writer may pass to the description of some modern processes. 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 opera- SIIJFICATION OF M^OOD. 157 tiori is 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 con- denser. This operation is repeated, until the pres- sure 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 between 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. For the relative claims of wood and rfietal as ma- terials for rails^ many facts ought to be considered ; wood is exempt from the inconveniences, dangers and expenses incidental to contraction and expansion 7 158 SILIFICATION OF WOOD. under variations of atmospheric temperature. Metal at an extreme low point fractures, and most lamen- table casualties result ; while under the fervid heat of 90 to 170^, the expansion of iron is so great as to displace the work on which the rails repose, and thus render the whole fabric unsteady and unsafe. From the Report on Wooden Railways the follow- ing extract is made : — " The length of the experi- mental line laid down near Yauxhall bridge was 174 yards, with gradients of 1 in 95, 1 in 22, and 1 in 9, and a curve of 720 feet radius. The speed attain- able on so short a line was of course limited ; but the power given to the engineer by the bite of the wheel on the wood (for the line was laid with wooden rails) enabled him to drive at the rate of twenty-four miles an hour, and to stop the carriage in a distance of twenty-four yards. In the presence of several engi- neers the carriage, laden with passengers, ascended an incline of 1 in 9, the rails being in a very bad state at the time from damp weather. " Since the introduction of wood paving, it may be calculated that a saving of one-half has been effected in the wear and tear of carriages, horses, and harness in those districts where it has been adopted ; a saving equally great can be made in the construction of railroads by the substitution of wood for iron rails. The rails may be made of beech or other hard Eng- lish timber, six or eight inches square, let into wooden SILIFICATION OF WOOD. 159 sleepers, and secured by wooden wedges, forming one great frame, or wooden grating of longitudinal and cross sleepers. " An engine weighing ten tons running on wood will have more tractive power than one weighing eighteen tons running on iron ; and as the concussion and abrasion on wood is so trifling, carriages built to weigh one and a half tons will be as strong as those having to run on iron weighing three tons. An im- portant question connected with this subject is the durability of the material of which the rails are com- posed. The engine employed for the experiment weighed about six tons ; it passed over the rails dur- ing the two months it ran 8,000 times in every variety of weather, which is equal to nearly seven years traffic of twelve engines per day. The rails consisted of Scotch flr, about nine feet long and six inches square ; and yet, upon examining them after the severe test to which they had been subjected, they exhibited no appearance of wear from the friction of the wheels on the upper surface, as the saw marks were not effaced. " The capability of wood to sustain the strain to which it must necessarily be exposed, especially when moving over it at higli velocities, has been satisfac- torily proved by the experience of the Great Western and other railways, wliere continuous longitudinal sleepers of wood have been employed, and experience 160 SILIFICATION OF WOOD. 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 proof that wooden rails cut from beech will bear the wear and tear of trains passing over it, it is well known that beech cogs have proven to last eighteen to twejity years when working in gear with an iron wheel. The rails on the Yauxhall line were pre- pared 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 trafiic of twelve engines per day for seven years, without any visible wear, it would be difficult to say how long the rails cut from beech, sustaining eighty-two tons pressure, would last. Some of the impediments with which railroads 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 capi- tal, in making the required excavations and embank- ments, or by the oftentimes ruinous system of tun- nelling, and after all, inclines of greater or less gra- dients are unavoidable, and prevent the line working economically. Curves on iron railroads are highly SILIFICATION OF WOOD. 161 prejudicial, especially if the radius be small, as the wear and tear becomes proportionably increased. " Now, by the introduction of the proposed plan, the evils arising from the obstacles alluded to would be very materially diminished ; for, in the first place, tbe surface resistance obtained by the elastic char- acter of wooden rails, enables a train to be propelled up inclines with much greater facility and ease than on rails constructed of iron. The adyantages of wooden railways thus constructed, in point of economy, comfort, durability, and as feeders to the great and central lines already formed, must be ap- parent to every one who has given the subject any consideration. " The result of a series of experiments, made to ascertain the proportionate power of the bite of wood over iron, has fully borne out the assertion of the patentee, that the bite of the driving-wheel on wood is nearly double that on iron. On the surface of an iron wheel four feet in diameter, a lever eight feet long was placed, with a weight of seven pounds at- tached to the leyer, three feet from the centre of the axis of the wheel ; tlie surface of the lever being iron at the tangent of the wheel, it required a weight of twenty-eight pounds attached to the crank to make it revolve. On substituting a wood surface for the iron one; it required a weight of forty-two pounds. Another experiment confirmed the result with the 162 SILIFICATION OF WOOD. iron surface ; a weight of twenty-eight pounds at- tached to the spoke of the wheel, at a distance of six and three-quarter inches from the centre, made it re- volve ; whilst with a wooden surface, it required the Barae weight to be attached to the spoke at a distance- of eleven and a half inches from its centre, thus clearly demonstrating the power obtained by the bite of the wood is nearly double the bite of iron. " Mr. J. M. Mason, (of Trent notoriety) when in England, devoted some attention to Prosser's system of wooden rails, with a view to their use in the South- ern States during the war, and in a letter to Mr. C. J. Bloomiield, he writes, ' I was most strongly im- pressed with i\iQ\r feasibility and durahility .'' " Timber Rot 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, it has been shown that for every two equivalents of hydrogen oxidized 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. Otliers admit that microscopical parasities of vege- table nature play an important part in the decay of wood ; but consider the presence of albuminious matter in the sap as necessary, which, according to 6ILIFICATI0N OF WOOD. 163 them, must also be first in a state of decomposition before it allows the growth of those organisms. Jn order to throw light upon this most important sub- ject, we propose first to tabulate a number of well- observed facts. Sound timber, when immersed in water, without access of air, will withstand decay for almost an unlimited 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 marches are rarely found decomposed. This is stated to be the case with the utensils dis- covered in the lake dwellings of Switzerland, Bavaria, and Lombardy, which must be at least ten thousand years old. Ilartig also describes 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 rv^spect 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 suffi- cient length of time. In England it is customary to lay the 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. 164 SILIFICATION OF WOOD. This tends to demonstrate the fact that the sub- stance which induces decay must be foreign to the timber itself. This substance is the juice that is chiefly contained in the vascular tissue, which forms a link between the bark and the wood. The compo- sition of this sap varies according to circumstances, as the variety of the tree, climate, season, ground, etc. The following are analyses of the sap : CD l.l . In 100 Parts. Elm ique ■oil ap of Vai p- 03 • m 5^ 3T06(a) 16.14 4.37(&) 13.34 6.31 20.93 30.57 '7*02 3.56 Organic Substance (not determined),. o.io Potassa with Organic Acid,. , 0.87 * 0.10 Extractive Matter and Salts, 33!70 98 '.93 62.66(c) 100.00 100.00" 100.00 (a) Gluten and Albumen, according to Solly, {b) Dextrin and Salt, (c) Water and Butyric Acid. Remarks. — The Cow Tree {Qalactodendron) is a native of the Cordilleras of Venzuela ; it furnishes, by incision, an enormous quantity of a white, thick liquid, which has the taste and some of the qualities of 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.) SILIFICATION OF AVOOD. 165 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 con- sidered as such, is exceedingly small, and with re- spect to the other trees, these analysis 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 liable to spontaneous decomposi- tion, or afi'ording the vegetation of fungi and lichens ! How unfounded is the assertion of Mr. Joseph B. Lyman, who, in an article on the preservation of tim- ber, states that "wood is mainly made up of woody fibre and a substance full of nitrogen " ! {vide Work- ing Farmer, November 1st, 1868.) 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 by similar causes which brought on the disease of the vine, potato, mulberry trees, and 166 8ILIFICATI0N OF WOOD. other cultivated plants, which make the years 1845, '48, '53, '57, and others forever painful to the memory. 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 witli 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 after- ward dried wood commences to rot, it is a sign that moisture has again penetrated ; for it is scarcely to be admitted that in all these cases the sap had been en- tirely removed. Timber decomposes the easier the more sap it contains, and if green trees are hewn when the vessels are overflowing with juice, one may look with certainty for diminished durability of the timber. Timber is not always the more durable the more dense it is, but rather when the even fineness of the grain continues to the pith of the stem. The Roman historian, Pliny, considers the resini- ferous woods as the most durable. Indeed, nature shows that this is frequently the case. The resinifer- ous red and white pines of Oregon and California are SILIFICATION OF WOOD. 167 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- situations, 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 alti- tude of one hundred and eighty feet, with a diameter of six feet or more, is said to retain its properties as long as the very best description of oak. ■ The fact that dried timber is, for nearly every pur- pose, far superior to green, has led to its being dried in the opeji air, or in confined rooms by means of heated air, or mixtures of air and steam. The first method is termed seasoning. Newly felled wood, in order that it may season properly, should be pro- tected from rain, sun, and strong winds. It should be piled up so that a circulation of air can take place from beneath. The shed in which the timber is dried should be paved and provided with sewers. Moreover, the re- lative position of the pieces of timber should be changed from time to time during the seasoning process. The necessary time for seasoning varies from two to four years. The proportion in which the woody fibre and water are to each other is very different.' It 168 SILIFICATION OF WOOD. varies according to the degree of dryness and the nature of the wood itself. According to Schiibler and Neufter, we have for newly felled woods the fol- lowing table : WOOD. WATER. Hornbeam. 18.6 per cent. Willow 26.0 Sycamore 27.0 " Ash 28.7 Birch 30.8 Oak 34.7 PedichOak 35.4 White Fir 37.1 Pine 39.7 Red Beech 39.7 Alder 41.6 Asp 43.7 Elm 44.5 Red Fir 45.2 Lime Tree 47.1 Italian Poplar 48.2 Larch 48.6 White Poplar 50.6 Black Poplar 51.8 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 holols ftom 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.Y5, The weight of one cubic foot of newly cut SILIFICATION OF WOOD. 169 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 Rum ford, 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 becomes very hygroscopic, losing or absorbing water according to the state of the atmosphere. Indeed, it appears that this property is never entirely removed. According to the author of an article on " Wood " in Appleton^s Dictionary of Mechanics^ some bog oak, supposed to have been buried on the island of Sheppy not less than a thousand years, was dried for a good many months, and then used for the manufacture of furniture. When divided into the small pieces re- quired for the work, it was still found to shrink. With regard to the shrinkage after one year's season- ing, it ranges from five to twenty per cent., and after a seasoning of four years from thirteen to thirty -two ^er cent. W. W. Bates, of Chicago, 111., contributes the fol- lowing data upon the shrinkage of green North Caro- lina live oak, cut at different seasons of the year, in the Report of the Commissioner of Agriculture for 170 SILIFICATION OF WOOD. the year 1866. The shrinkage after one year's sea- soning was as follows : Loss of weight in summer-cut logs, in bark. . .5 per cent. IjOSS of weight in winter-cut logs, in bark. . . .6 " Difference in favor of summer-cut logs. . . 1 per cent. Loss of weight in summer-cut squared timber. 5 per cent. Loss of weight in winter-cut squared timber . 5 " Difference 0 per cent. The shrinkage after four year's seasoning gave : Loss of weight in summer-cut logs, in bark. . .23 per cent. Loss of weight in winter-cut logs, in bark. . . .27 " Difference in favor of summer-cut logs. ... 4 per cent. Loss of weight in summer-cut squared timber. 23 per cent. Loss of weight in winter-cut squared timber. .22 " Difference in favor of winter cut timber. . . 1 per cent. 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 longi- tudinal 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 SILIFIOATION OF WOOD. 171 valuable for nearly all the purposes for which it is used, but particularly for the hubs, spokes, and panels of carriages, etc. — Dr. Ott^ in Eng. <& Min. Joicrnal. PRESERVING WOOD. ROBBINs's PROCESS. 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- ways cost twenty-five 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 railroad 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 atmo- spheric precipitates, rain, dew, and snow, which have percolated from higher levels. Kainless regions are always deficient in woodland, and there are innumer- able instances where vast and fertile tracks of land 172 SILIFICATION OF WOOD. have been changed into barren and unhealthy desserts, simply because they have been stripped of their forests. Therefore, in lengthening the duration of wooden structures, we, at the same time, prevent the destruction of our forests, thus leaving to the coming generations the same resources which we have in- herited from our forefathers. We now propose to examine the process of Mr. Louis S. Robbins, which was patented in 1865, and purchased a year later by the "J^ational Patent Wood-Preserving Company" of New- York. It goes also under the name of the " oleagin- ous vapor process," and has been described in the daily and weekly press, under the title, " Discovery of one of the Lost Arts of the Egyptians." The process may be briefly described as follows : The wood to be treated is placed in an iron chamber, which is con- nected 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 com- pletely protected against the moisture of the atmo- sphere, but also that it is rendered "nearly as inde- structible as granite." In order to comprehend this process, it is necessary that we should examine the nature of the products which are given off in heating coal-tar, and the changes which they produce on SILIFicATION OF WOOD, 173 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° Falir., 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 w^liich 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 olf a little earlier, but the giving off of naphthalized oils continues up to 550^^ Fahr., wlien a resinous, yellowish product ap- pears, which can be easily kneaded between the fin- gers. The remainder is the black, j)itchy 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- SILIFICATION OF WOOD. 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 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 al- ways 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 Hutch Government Engineers. (See Dingier' s Polytechnic Journal.) They discovered that after thirteen months' exposure, piles which had been cre- osotized 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 quar- ter. The same fact was also reported by Mr. Steven- son, 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. Steven- SILIFiCATION OF WOOD. 1Y5 son 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 offensive 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 having ever been known to the world prior to its dis- covery by Mr. L. S. Kobbins. It is claimed to be as new as was the sewing-machine or the telegraph. We presume that Mr. Kobbins 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 chamber, which is connected w^ith one or m(5re 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 tliese 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 with these vapors, the surplus is drawn off, and vapors from another still, containing the heavy oils, are admitted into the chamber. 176 SILIFICATION OF WOOD. Finally 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. Hobbins, but was re- commended, in 1858, by Dr. Krieg, in connection with soluble glass, for the preservation of all w^ood- work against fire and rot. — From the Manufmturer and Builder^ Jnly^ 1869. Wooden Roof 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 have frequently caused deflagrations 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 300 to 350^ is led into them for several hours they are dried and throwm into a w^eak solution of liquid silica, standing about 25 B. 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 throwm over them or sprinkled over them with a broom, w^hen quite dry they are fit for use. Tliey SILIFICATION OF WOOD. 177 will not burn, nor be lighted by the sparks, if exposed to a direct fire, will not light in a surround- ing fire. An intense heat of long duration may char them on the surface, they are however quite safe against any inflamation. Street Pavements. As a rule, competent engineers express doubts as to the merits of the Nicolson, and of wooden pave- ments of all patterns. In the Nicolson structure the road-bed is of sliarp^ clean sand, of the pro])er 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 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 a foot or nearly in depth. This opening is tilled 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 sufficiently boiled to be tough and fibrous, but not brittle, upon 178 8ILIFICATI0N OF WOOD, which is sprinkled a layer of line gravel and common sand. The Stafford pavement differs from the ^»[icol- son in tlie 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 Nicolson. 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 latter advantage can only be estimated by per- sons who have taken occasion to note the extent to which one falls into the habit of measuring the dis- tance of a veliicle from any given crossing, by the ear ; and one of the main liabilities to accident, oc- 179 SILIFICATION OF WOOD. curring from wooden pavements, is the muffling or comparative muffling of the hoof-beat. In this re- spect, in fact, any form of concrete pavement possesses material advantages over either the stone block, which exaggerates the rumble of wheels and obscures the hoof-beat, or the wooden pavement, which re- duces both in about equal proportions. In a word, a grave objection to the Nicolson pavement is the fact that in just one respect it is a trifle too noiseless for the safety of pedestrians in crossing, especially in 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 1851-, 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 180 SILIFICATION OF WOOD. thoroughfares. Up to 1866, 96,000 square yards had been put down ; in 1867 the surface added was 54,000 in Paris proper, and 84,000 in all in the de- partment of the Seine, making a total in thirteen years of 180,000 square yards. The contract of the Cie Grenerale 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 Mac Ad am was applied to the old boule- vards, 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 side- walk as now used. The whole surface of streets and sidewalks is now constituted as follows : SQUARB METRES. Streets — paved Macadamized. . Of Asphalt . . . 4,833,643 2,146,005 165,164 Sidewalks — of granite Paved Total 7,195,303 545,939 Bituminous 14,024 1,192,414 Total 1,752,377 SILIFICATION OF WOOD. 181 Grand total 8,947,679 Equivalent in square yards to 10,701,416 The relative cost of the three as constructed is worthy of attention, and may be added, together with the annual cost of repairs, to the square yard. The generalization exhibits the following figures : COST PER SQ. YD. ANNUAL REPAIR. Asphaltic road $2 50 25 Belgian porphyry pavement. . . 3 00 to 3 67 08 i to 25 Macadamized 1 17 42 to 50 The first cost of asphalt streets is greater than that of macadamized, while the cost of repairs is considerably less; and, again, the first cost of the asphalt is less than that of the Belgian pavement, while the expense of repairing is greater. The as- phalt coating, one sixth of a foot thick, is supported upon a roadbed of concrete, composed of ninety parts gravel to forty parts of mortar, about a quarter of a foot in thickness, and rested upon the comj^acted soil bed beneath. Provided the requisites of thorough surface and imder drainage have been observed, the asphalt roofing being utterly impervious to water, the roadbed of concrete waxes harder and drier with age, and, once made, is imperishable. Repairs are easy, and consist simply in cutting away the damaged roofing of asphalt and replacing it with new. As compared with the Belgian pavement, the liability to fall of horses being driven' over tlie asphaltic road is 8 182 SILIFICATION OF WOOD. 1 in 1409 to 1 in 1308 on the former, proving the Buperiority of the asphaltic surface in this respect — that is, in surety of foothold. The concrete known as heton Coignet differs from the ordinary roadbed concrete in being an artificially formed sandstone of great durability and strength^ and of extensive application in civil engineering in all its ramifications, from the manufacture of sewers to the construction of aqueducts, from the fabrication of roadbeds to that of underground vaults of the ut- most capacity. The best heton endures a rushing strength four and three-fourth times that of the best brick, fifty per cent, greater than that of limestone, fifty per cent, greater than that of sandstone, and about forty per cent, less than that of the strongest granite, to thirty-five per cent, more than that of the inferior qualities. For common use a good heton is compounded of four parts of sand and one part of fat lime, to which, for extra strength, one half part of Portland cement may be added. It could be manu- factured here at an expense of four dollars per cubic yard, and for roadbed, a quarter foot thick, at sixty cents per square yard. The embankment on which runs the Avenue de FEmpereur, at the Trocadere, is supported by a wall of this material forty feet in height, for the distance of a quarter of a mile ; and, in general, the subject of its application is now being discussed and experimented upon by the best engineers SILTFICATION OF WOOD. 183 in France, with a view to extend to the utmost tlie constructive capacity in engineering of so inexpensive a meterial as that developed by the invention of M. Coignet ; while in the sewerage system it is rapidly superseding every thing else. In it no doubt is, at the end, to be sought the solution of the sewerage problem in this city, if the administration thereof ever falls, with the needed powers of discretion, into the hands of a competent board of engineers. What is wanted in the problem is the boldness to break loose from worn out ideas and apply the best invention of the age to the development of a better and more adequate system — a quality which lias beenstartliiigly exhibited, witli equally startling and successful results, in the administration of the Departments of the Seine and in the construction of public works in Paris for the past ten years. Most foreigners travelling in France remark the excellence of the macadamized roads, and not un- frequently suppose that there must be something peculiarly favorable in the nature of the soil or some- thing unique in the method of construction. The supposition is not true to fact, however ; the quality of the roads in France being attributable to good en- gineering and care and exactness in all the processes of construction and preservation. In fact, in the system of Tresaquet and Simplon the system intro- duced into England by MacAdam in 1816 had been 184 SILIFICATION OF WOOD. anticipated more than half a century. MacAdam copied Simplon in his road-bed, while Telford did nothing more than return to the system founded by Tresaquet in place of the still earlier road-bed of flat stones. The roads of France are simply illustrations of what may be done by good construction rather than of any superiority of facilities ; those of the city of New- York are to a great extent examples of the result of slovenly construction with sufficient facilities for the best of work. And this leads to the general principle, that of the several pavements in use any one is practically good enough for all purposes when well constructed. The defect is not in the theory of the pavement itself, but in the defective and slovenly application of it under the contract system. As in railroad-building, with the result of innumerable accidents, so in street-paving defective road-bed is the great sin of the contractor ; and, as in railroad-building, the United States cannot be compared with France or England for thoroughness and attention to the details which result in perfection, so, in the matter of pav- ement and the la3dng of it, American contractors on the average are slovenly and inefficient. Contracts for street-paving are annually awarded in this city to persons whom a competent European engineer would not trust as workers under a superintendent ; and thus, through ignorance in many cases, through greed in many cases, through both together existing in many SILIFICATION OF WOOD. 185 cases, it is seldom tbat New York can boast of a section of pavement properly put down with due attention to all details. What is The Coming Pavement, or which, of the several kinds now bidding for popular favor, is a question not easily answered. As a rule, competent engineers express doubts as to the merits of the Nicolson, and of wooden pavements of all patterns. In the Nicolson 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 super- structure are of Southern hard pine, three by four, and are set on end in rows, crosswise of the street — the blocks before setting being dii)ped to half their length in a bath of hot coal-tar. Between the rows of blocks intervene ])ickets o\» thin boards set on edge and leaving an opening between the rows of blocks, of a foot or nearly in depth. This opening is filled with clean screened gravel rammed down with a pavor's rammer, and an iron blade made for the pur- pose, and the surface is covered with hot coal-tar. The gutter exhibits its lowest point half a foot from the curb. The whole surface is covered with coal-tar sufficiently boiled to be tough and fibrous, but not brittle, upon which is sprinkled a layer of fi^ne gravel 186 SILIFICATION OF WOOD. and common sand. The Staftbrd pavement differs from the Kicolson in the laying of large blocks prepar- ed 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 Nicolson. Both obviate certain objections in surface way, which pertain to the Belgian, in the wear and tear of vehi- cles 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 supe- riority valuable as a 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 latter advantage can only be estimated by per- sons w^lio have taken occasion to note the extent to which one falls into the habit of measuring the dis- tance of a vehicle from any given crossing by the ear; and one of the main .liabilities to accident occuring from wooden pavements is the muffiing, or compara- tive muffling, of the hoof-beat. In this respect, in fact, any form of concrete pavement possesses mate- rial advantages over either the stone block, w^iicli ex- aggerates the rumble of wheels and obscures the SILIFICATION OF WOOD. 18T hoof-beat, or the wooden pavement, which reduces both in about equal proportions. In a word, a grave objection to the Nicolson pavement is the fact, that in just one respect it is a trifle too noiseless for the safety of pedestrians in crossing, especially in these days when every driver seems to be possessed with the devil to run over somebody. 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. In the great desideratum of simplicity, as well as in the ease of repair, the Staf- ford seems to possess advantages over its elder in the field ; but there is no likelihood that either will supersede the stone-block to any great extent. The coming pavement, in fact, from all indications in- cluded in the survey of the subject, is not to be found in any use of wooden blocks in any form or under any conditions. If the Belgian (stone-block) is ever superceded — and it will be within the next twenty years — that supersession will have been brought about by inven- tion, in the way of practicable concretes. The as- 188 SILIFICATION OF WOOD. phaltic road in Paris has given an impulse to investi- gation in this direction which will not stop until some practicable substitute for the stone-block (Belgian) has been developed. The age of block-stone pave- ments is in its last quarter — to borrow a metaphor from the moon. The merits of the wooden pavement are its noiseless- ness, its reduction of the mortality of horses, its reduc- tion of the wear and tear of vehicles, and its effecting a utilization of the utmost percentage of draught force, and these are all merits to an equal degree of the as- phaltic road, and may be made merits of any concrete whatsoever. The increased mortality in horses occa- sioned by the Russ and Belgian and other stone pave- ments 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 Nic- olson, 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 Nicol- son can be regarded as equal to the necessities of Broadway at all. It is seen, therefore, that while the stone block (Belgian or Russ) is open to grave objections on the one hand, the wooden pavements- (Nicolson and Staftbrd) are open to equally serious objections, on the other hand, on the score of lessened SILIFICATION OF WOOD. 189 durability. The concrete pavement — the value of which has been happily settled in Paris — elfects 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 in this direction, nothing is hazarded in predict- ing that the ideal or coming pavement will be devel- oped from the present crude concretOvS. The asphalt road, one triumph of concretion, the hetoii Cvignet^ another triumph in a direction of equal ])ractical im- portance, the attempts at concrete from inexpensive material in this country, all point to tlie hypothesis that the solution of the long-mooted pavement prob- lem is at hand, in the evolution of a concrete roadway combining the durability of the stone-block with the advantages 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 pro- portions with tar, rosin, and asphaltum. The road- 190 SILIFICATION OF WOOD. 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 sufficiently 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 commended by thoughtful engineers as a step in the right direction. The sonorousness of the hoof-beat, as enabling the pedestrian to measure the imminence of passing vehicles, is an element of concretes over wooden pavements, illustrated in an eminent degree by the asphaltic road, the value of which as a preven- tive of accidents cannot be overestimated. 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 SILIFICATIOX OF WOOD. 191 cities, the concrete must therefore be ranked as supe- rior to either of its competitors, with some most im- portant 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 sewarage system having been carried out, atten- tion may be directed to the production of an inexpen- sive concrete, analogous to the asphaltic road. Discussion on the subject as it relates to the city would be incomplete without due consideration of the Typical Historical Pavement, based upon the Roman system, and its susceptibility for improvement ; for it is a fact that a large 'class of conservative engineers still look for the advent of the ideal pave in some modification of the stone- block on the concrete road-bed. The completion, during the past week, of the relay of the Broadway pave, at an expense of nearly 8500,000, recalls the fact that no question exists as to the vulue of the sub- structure of concrete. The question is as to super- structure. Large stone blocks on a road-bed of sand form the major part of the pavement of the city — the large block pave being less expensive than the small. On Broadway the unique feature introduced consists in splitting the blocks by a lateral fissure, leaving them in point of superficial appearance parallelo- 192 SILIFICATION OF WOOD. grams a quarter of a foot in width, against a foot or thereabouts in length. This, by quadrupling the number of joints, affords a sure foothold for horses, especially as the blocks are laid traversely — the line of travel crossing the linear of the nave and surface at right angles with the length, with the effect to afford an average of four clinging points for the horseshoe in the new pave to one in the old. This decreases the liability to slip, really dividing it by four, and, with the concrete bed, fulfils the ideal of the old Roman pave. The want of elasticity is, how- ever, in nowise obviated ; the difficulty of traction ia by no means lessened, the jar and volume of sound are not in the leastwise substracted from. The sani- tary purpose is met, and percolation is prevented ; but no part of the $10,000,000 annual wxar and tear of horses and vehicles is saved; and this is a matter to be considered in the pavement of a city. The im- portant question is to settle upon the desiratum in the way of superstructure. The true method of in- vention would seem to be to make beton Coignet the basis, and to this to superadd some fourth ingredient to develop the needed elasticity, which may be effected by the addition of the liquid silicates. Tar boiled to the point of elastic solidity, or asphaltum, which can be procured at twenty dollars per ton, currency, might be added in small proportions to the heton ; and in this way, by experiment, a concrete 8ILIFICATION OF WOOD. 193 might be developed equal in all respects to the as- phaltic road, now so popular with the engineers in Paris. The hugh quarries of trap along the East River render the Russ pavement tolerably inexpen- sive ; and hence, in order practically to supercede it^ something must be produced which can be put at $2.50 or less per square yard, and as durable as the block-stone. An able and competent engineer esti- mates the loss in horses, extra wear of vehicles and extra horseshoeing in the cities of the United States, occasioned by block-stone and cobble-stone pave- ments, at — On horses $15,000,000 On vehicles 20,000,000 On horseshoing 21,000,000 Total $56,000,000 The province of invention in respect to pavements, is to save this vast amount by the substitution of a concrete upper structure as inexpensive and durable as the Belgian, and as elastic and easy as the wooden, which has failed in the respect of durability as well as over-expensiveness, and can never be generally adopted . Most roadway surfaces, it is clear, should afford, in the first place, certain and firm foothold for horses ; secondly, as little resistance to wheels as possible ; thirdly, permanence, as regards structure and firm- 194 8ILIFICATI0N OF WOOD. Tiess ; fourthly, such qualities as will ensure ease iti draining and cleaning; and fifthly, facility for re- moval and replacement. There can be no difference of opinion about these conditions. No matter how thoroughly excellent a pavement may be otherwise, if it only affords a slippery and unstable footing for horses, it is worthless, and its perfection in other points wasted. The greater the amount of strength the horse has to exert the more increased is his lia- bility to slip. This arises from the fact that his hoof always strikes the pavement toe first, the point of contact then becoming the fulcrum about which his leg moves as a lever, so that the greater the load the greater the pressure on this fulcrum, with resulting increased tendency to slip. Hence, no pavement is at all perfect which presents a smooth, hard, un- broken surface, or that has any great longitudinal or transverse slope. A pavement, to offer as little resist- ance to wheels as possible, must have great hardness, smoothness, evenness, and no elasticity. As to per- manence as regards surface and structure, any pave- ment requiring frequent renewals is an expensive one, no matter how small its original cost. True economy will allow a most liberal original outlay for a pavement which, if satisfactory in other respects, aflbrds permanence. The cost of frequent renewals and repairs is not only a large item of direct expense^ but while the pavement is settling and wearing 8ILIFICATION OF WOOD. 195 smooth the draught and the wear and tear of vehicles are increased, and the necessary blocking up of the roadway while the repairs of construction are actu- ally in progress, causes delay and time-consuming detours, unavoidably crowding the adjacent streets, while greatly inconveniencing warehouse owners by preventing the delivery and loading of goods imme- diately at the warehouses. To secure permanence we must consider locality, material, construction and surface. As to the locality, it is essential to examine the nature of its traffic and transportation, the nature of the soil on which the pavement must rest, and the climate to which it will be exposed. The nature of the traffic should be specially studied, as it would be manifestly injudicious and wasteful to place a stone block or iron pavement on the roads of pleasure grounds, or, ince versa^ to transfer a park gravel road to a crowded business street. We should note the character of the soil, whether it be properly drained by nature or artificially ; whether it is composed of homogeneous, dry and incompressible material, like sand, or is soft and spongy, as it invariably is when the street has been much used without pavement, or has been filled in with building or street rubbish. The climate of the locality must be considered, as some pavements lasting well under certain conditions of moisture and temperature become speedily perish- able when these conditions are changed. This, per- 196 SILIFICATION OF WOOD. haps, is particularly noticeable in the use of wooden or macadamized pavements. Pavement material should be thoroughly examined with regard to it& tendency to decay and disintegration, to tearing to pieces or grinding up. With regard to construction, we must separately look to the foundation and the upper part, or pavement proper. Without proper foundation or bed no pavement can attain much longevity. It must be thoroughly dry, rigid or in- compressible, and when, uniformly thick pavement blocks are used, even-surfaced. A clean pavement is not only healthy and sightly, but economical. The pavement surface should be so graded as to clean it- self to a great extent during every rain-fall. This may be most efficiently accomplished by the longitu- dinal slope of the street, very slight lateral slopes being needed. Yarious Systems Adopted for Broadway Pave- ments. A great variety of systems have been adopted for roadway pavements. The most convenient classifi- cation of them is into gravel compositions, broken stone, plank, wooden block, cobble stone or pebble stone block and iron block pavements and tramways. The first attempts at pavements generally com- mence with the use of gravel. Roads thus made possess the advantages of cheapness of material and SILIFTCATION OF WOOD. construction. In the Park, where there are probably the most perfect roads in this country, they have shown better endurance than those made on the mac- adam plan. Gravel roads, when properly constructed and maintained, are comparatively smooth and noise- less, besides aftbrding excellent foothold for horses. The great objections to them are that they cannot he kept firm enough to afford easy draugiit 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 grinding and crusliing 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 tliem from Avasliing 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 asplialt pavement of Paris, concrete, heton^ gutta percha, slag, cinder, and other pave- ments ; also, those formed according to the experi- ments of McNeil, partly of broken stone and partly of pieces of cast metal, laid on a sub-pavement of rubble stone. The asphalt pavement 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 198 SILIFICATION OF WOOD. hot rammers until it is very hard 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 exces- sively so at a freezing temperature. 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 Lon- -don. The Russ pavement, the nearest approach to -SL perfect pavement yet constructed in this city, has, in imitation of the Horn an pavement, a heto?i founda- tion 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 ^re 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 Broad- way, this excellent pavement has most signally failed, the surface of the granite used polishing and affording dangerous foothold. 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 substi- tuted here in an imperfect manner. The blocks now used are of a coarser granite, twelve inches long, nine SILIFICATION OF WOOD. 199 inches deep, and four inches wide, the courses run- ning 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 been quite extensively adopted in this city. This pavement has the advan- tage of cheapness, and, if well laid, of economy, the necessary and actual cost being a little over one- half that of the Nicolson 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. Ikon 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 hore 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 or 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 200 SILIFICATION OF WOOD. 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 l^icolson pave- ment, and by its extreme hardness will give much less resistance to wheels. Being of uniform quality, all parto will wear equally^ and as perfect a ftice will 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 axles, and of course increases with roughness of pavement surface. Iron, furthermore, loses but little from oxidation. It can be kept as clean as the Nicolson pavement, with the advantage of non-absorption. It has one great advantage in being made so as to be easily and readily removed and repla(;ed, the blocks formed from the same pattern, being exact counterparts. The Fisk 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 SILIFICATION OF WOOD. 201 on the roadbed and heavily rolled until a depth of four inches is attained. The finer portion is then mixed with clean sharp sand, warmed, and then thor- oughly mixed with 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 or two inches is attained, after which the surface is covered with an excess of clean sharp sand and again rolled. The Nicolson Pavement. We now come to the subject of wooden pavements. The first general attempt to use wooden blocks for 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 oft' in the list of wooden pavements adopted in this city is the Nicolson 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 for 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 202 SILIFICATION OF WOOD. 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. Be- tween 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 payor's rammer 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 covered with fine gravel and com- mon sand. After the top gravel has become packed on the surface and in the grooves, the street is swept. The M'Gonegal Pavement. This pavement, claimed to be an improvement on the Nicolson, to which it is similar, consists of a foundation of two inches of heton^ 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 diame- ter, 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 SILIFICATION OF WOOD. 203 or key. The wood used for blocks and keys is pre- pared for preservation by Bobbins' process. In lay- ing, the blocks and keys are dipped in hot coal tar. The perforations in the blocks are filled with clean roofing sand. The pavement 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 lias been laid in this city, a foundation of flooring 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 Nicolson, 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 off so as to conform to the desired arch or crown of the street ; then blocks of sound pine or spruce wood three inches in thickness, and six inches iu 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 204 SILIFICATION OF WOOD. the sand or earth with rammer and swage until tlie 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 ram- mer and swage, then the gravel saturated with hot €oal tar, and the whole surface covered with hot coal tar, and lastly, the pavement covered with fine gravel or sand. The Brown and Miller Pavement. This pavement is also similar to the Nicolson, 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 Robbins' Pavement. This is another of the multifarious wooden pave- ments recently introduced in this city. It is very similar to the Nicolson, only the wood used is first prepared by Pobbins' patent wood preserving pro- cess. The Stafford Pavement is only another imitation of the great original Nicol- son. The blocks are dressed to a uniform thickness, grooved in the middle with a double dovetail, two SILICIFICATION OF WOOD. 205 and one-half bj three-fourtli inches, each side of the block bevelled 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 Univer- 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. WOODEN pavements, VeVSUS STONE AND CEMENT. The failure of the concrete in Fifth Avenue for which the citizens were mulcted in the sum of half a million of dollars, and which was taken up during the winter on account of its uselessness. The various stone pavements, which have from time to time been brought forward by the patentees and speculating companies, have all brought the unbiased and practi- cal men to the conclusion that for comfort a wooden pavement in such streets as Fifth Avenue, would prove by far preferable to any other, provided it is made durable, at the same time a proper concrete as mentioned in these pages in connection with silicates may with great propriety be employed as a base but not as a capping for either stone or wooden pave- ment ; whether this shall be a concrete or whether the base shall be of planks properly prepared and 9 206 SILICinCATION OF WOOD. Bilicitied so as to construct the blocks upon it, is a matter of great importance, and is well worth a re- flection and experiment upon a small scale, but not hazarding an outlay of perhaps a million of dollars, and the experiment to prove again a failure. The following method of application is recommen- ded by the author : The planks and wooden blocks, intended as pave- ment, the size of the planks being from 10 to 12 feet in length and 1 inch in thickness, 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 con- tained in the cells of the wood and by the boiling the coloring matter is extracted from the wood; when taken from the boilers, they are brought in drying chambers of high temperature, and then removed to vats containing 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 in vats containing hot silicate of soda, stand- ing 20 B. and left therein for 4-6 hours ; they are then removed 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 SILICIFICATION OF WOOD. 20T of silicated hydraulic lime or cement. The interstices of the ends of the blocks may likewise be made tight by applying a silica cement between each. The Mode of Application. The frequent enquiries how to apply the soluble glass, and how much is required for spreading over certain surfaces, may herewith be recommended in the following manner ; application for hardening stones as a mortar between bricks, or any cement or composi- tion for wall, cistern, cellar, or roofing. In all cases the liquid soluble glass, either the silicate of soda or potash, or both combined, are diluted with equal quantities of water so as to stand 25'^ B, If strong cements, or lutes, where various other substances along with the dry silicate and metallic oxides are to be employed, the soluble glass is not diluted but employed from 30-35*^ B, suffi- ciently to make a plastic composition ; but where it is intended for mending or filling 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. For painting or coating on stone, it is useful to apply the dilute by a syringe, and if necessary, re- peat tlie operation 2-3 times after each drying. For preserving monuments, tombstones, marble columns, 208 SILICIFICATION OF WOOD. 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 expensive), lead, zinc, or limewash, by means of a paint brush and according to the con- dition of the stone as to porosity. If the chloride of calcium, chloride of iron, or dilute hydrofluoric acid are applied upon the surface of the stone, 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 indispensible 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 where the substances are to be painted or undergo a silification, 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 cover- ing 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 quali- ties, such as for instance, the flrst coat may consist of part of silica to 2 parts of water, and another of equal quantities of water, and the last coat the dilu- tion to be 1 part of water. SILICIFICATION OF WOOD. 209 Wood and timber of every description may be treated witb the concentrated silicates. For Preservation of Walls. It is well known that brick absorbs its weight of moisture and requires much attention. The 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 the bricks upon which it is to be applied, a heavier mixture being used upon porous walls, and a lighter one on those of denser texture. After the silicate has become thoroughly ab- 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 fills 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 watertight, and, as the pores of the bricks are thoroughly filled for a consi- derable depth from the surface with the insoluble compound, which is entirely unaffected by atmos- pheric influences, no subsequent process is necessary. ^10 SILIOIFICATION OF WOOD. The Protection of Rail Eoad Sleepers, Cross Ties, Frame Houses, Telegraph Poles, Timber, Staves, Shingles, Laths, Tanks, Tubs, Casks, Barrels (Petroleum, Kaptha, Spirits Turpen- tine, Alcohol, Linseed Oil), Cisterns, and Every Description of Wood, against Fire, Dry Rot 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 matter, is effected by exposing for from four to six hours to boiling water, containing about one per cent, of soda ash in solution. They are then with- drawn 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 solution of silicate of soda standing 20® B., in which they are left for ten or twelve hours. When removed from here a weak limewash is applied with a brush or sponge, consisting of 10 lbs. slacked lime to 40 gallons of water, when likewise they are re- moved to a dry or hot air ; after that a weak wash of chloride of calcium is thrown or brushed over them when nearly dry. The process is then finished, and the articles so prepared will resist the elements aa SILICIFICATION OF WOOD. 211 above stated. They increase in weight by this pro- cess about 6 per cent. After this treatment, they assume upon the first drying a glazed appearance, and the pores are filled with insoluble silicas precipi- tated by the action of the tar liquor upon the alkali of the silicate of soda. Barrels which have been treated may be rendered perfectly impervious by fill- ing up the chimes (the inside of those barrels having been treated with the silicate of soda and chloride calcium) with a thin silicated cement applied on the interstices. No air nor any liquid will then have any eftect ; the lightest liquid may then be kept in those prepared barrels without escaping — flour, but- ter, lard, and many other perishable substances may be kept for 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 ])oles^ which are from twenty to thirty feet long, require a difter- ent treatment for their seasoning before they undergo the silification. 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 pro- cess of silicate of soda, limewash and chloride of cal- cium, as described, will render them proof against fire and dry rot. 2n CEMENTS. The following Cements, Whitewash and Concretes have all been tested, and deserve a general introduc- tion : The Silica Cement a Preservative 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 proper 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 bot- tom of the iron ships by means of a brush, and before becoming quite dry to dust over the paint more powdered manganese. The Most Adhesive Insoluble Cement. Blacklead, 6 lbs., are mixed with 3 lbs. slacked lime, 8 lbs. sulphate of raryta are mixed with 7 lbs. of linseed oil ; the whole mass is well mixed together 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 de- sired objects, uniting at the same time steam and hot water. The cheapest Lubricator for locomotives, en- CEMENTS. 213 gines and machinery is prepared from a mixture of silicate of soda liquid at 25® B.' added to fine plum- bago, talc and aspestos in equal quantities, so as to re- tain the thin plastic condition, and capable of drop- ping it on the journals in very small portions. The Cheapest Whitewash^ which is very durable for indoor and outdoor work, is prepared by the following composition : To 1 lb. slacked lime and 1 lb. sulphate baryta, add 1 pint of silicate of soda and 1 pailful of hot water ; stir the materials well toge- ther, and use it at once. If the color is intended for a yellow 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 cheayj for wooden fences along railroad 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- 214: CEMENTS. titles, made plastic with the liquid silicate, and ap- plied at the joints, and worked over with fluid chlo- ride of calcium, and when quite dry let some weak hydrofluoric acid pass over the cemented joints. This cement will be permanently impervious to water, and will not crack. The same composition is quite suitable for brewries, 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 bridge at London, and will state that the addition of silicate of soda to the concrete will undoubtedly en- sure a great saving. Tail's system has been used in the construction of a large number of houses in Paris, erected under the directions of the emperor, who takes great interest in the improvement of the working classes. This con- has also been applied in other parts of Europe, and to some extent in the United States. The work can be performed by ordinary laborers, who, after four or five days' experience, acquire all the requisite expertness. Even boys have been suc- cessfully employed in this kind of building. The only skilled workman necessary is a common carpen- ter, whose duty is to adjust the framework or appa- ratus to receive the successive courses of material, CEMENTS. 215 and place joists, doors, and window-frames properly. » The apparatus is designed to construct eighteen inches in height daily over the entire extent in hand, what is done in the evening of one day is hard next morning, and quite strong, the best proof of which is that the wall itself, as it rises in height, supports the necessary scaffolds. A double curb, entirely sur- rounding the upper part of the walls, serves to hold the plastic material in place, until it acquires suflS- cient hardness to support itself. The material consists of one part of Portland cement to eight parts of coarse gravel. The cement and gravel are first 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 to- gether. 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. Nor do heavy rains appear to injure it in the slightest degree, though they may chance to fall ere the concrete has hardened. The 216 CEMENTS. walls can be made straight and even as it is possible for walls to be, and the corners as sharp and neat as > if they had been formed of the most carefully dressed stone. Concrete makes excellent floors, and the walls and floors are quite impervious to vermin of all kinds, and also to wet. Many kinds of building bricks will absorb water ; hence, brick houses, when the walls are saturated with water, are cold. This is not the case with houses constructed of concrete, as it is non- absorbent of moisture, and such houses must be, therefore, more healthy. This novel mode of building houses has excited great interest in the neighborhood of Runnamoat, Ireland, and the proceedings have daily attracted numbers of people from all parts. While concrete may be used in constructing build- ings of every description, it is peculiarly adapted, from it cheapness, for the construction of cottages for laborers, and also for farm buildings. Its cost is not more than half that of brick-work ; almost any mate- rial can be used along with the cement, and as we have already shown, the most ordinary class of coun- try laborers are quite competent to carry out the de- tails of the system. With reference to its adaptabil- ity for large buildings, we may mention that a ware- house seventy feet long, fifty feet wide, and sixty feet high, five stories in all, has been erected on Mr. CEMENTS. 217 Tail's system for Mr. H. Goodwin, Great Guilford street, Southwark, England, and that gentleman tes- tifies in the warmest terms to its satisfactory charac- ter, and is making arrangements at the present time for the construction of another similar building. The warehouse already erected has attracted universal ad- miration from the practical and scientific gentlemen who witnessed its erection. The chief element of success, when the cement is of good quality, seems to be the thorough mixture of the dry materials, to secure uniform strength. Concrete Bridge. The tests applied to the experimental bridge of concrete, set in cement, erected over that branch of the Metropolitan District Railway which forms one of the junctions between the circular line and the West London Extension, prove conclusively the re- liable character of concrete exposed to compressive strains. The structure experimented upon spans the open cutting between Gloucester-road Station and Earle's Court Road. It is a flat arch of 75 feet span, and 7 feet 6 inches rise in the centre, where the con- crete is 3 feet 6 inches in thickness, increasing to- wards the haunches, which abut upon the concrete skewbacks. The material of which the bridge is made is formed of gravel and Portland cement, blended in the proportions of six to one, carefully 218 CEMENTS. laid in mass upon close boarding set upon the cen- ' tring, and enclosed at the sides. In testing the bridge rails were laid upon sleepers over the arch, which brought a load of two seventy-fifths of a ton per foot upon the structure. Seven trucks, weighing, toge- ther with their loads, forty-nine tons, were formed into a train, having a wheel base of fifty-seven feet ; hence the rolling load amounted to forty -nine-fifty- sevenths of a ton per foot run. The deflection pro- duced by the passage to and fro of this train four timea was noted upon a standard, cemented to the side of the arch, at a distance of one-third the span from the abutments. When one side of the bridge was loaded, the extreme rise of the branch on the opposite side was about one-sixteenth of an inch, which was pro- duced by a maximum strain of 10 tons 14 cwt. per square foot. At a subsequent trial, a mass of gravel 10 feet wide and 3 feet thick at the crown, and 6 feet deep at the haunches, was laid over the bridge, and upon this ballast was placed the permanent way* After an interval of a few days, the trucks, loaded a& before, were passed over the bridge, at first in pairs, and finally all together. In this test the strain upon the concrete was as follows : The weight of the arch, as before 7 tons 17 cwt. 170 tons of ballast 4 tons 8 cwt. Strain per square foot from dead load 12 tons 5 cwt. Strain per square foot from passing load . . 2 tons 17 cwt. Total strain per foot 15 tons 2 cwt. CEMENTS. 219 After repeated transit, the load was left upon the bridge all night, and the arch, upon examination^ showed no signs of failure or distress under the severe strains to which it had been exposed. The Soluble Glass as Manure for Grapevines* By putting the dry silicate of soda at the roots of grapevines, witl^ or without the addition of phosphate of lime, has by experiments proved of immense bene- fit to the thriving of the vines to a proper thickness, and the grapes of uncommon size. Soluble Glass a Substitute for Soap. A chemical compound is effected by the combina- tion of an alkali with silica, which possesses a greater affinity to the first than the acid of either grease or stearic and oleia acids have in coarser soap. On account of the soap which generally contains the caustic lime, that compound prepared by the admix- * ture of soluble glass possesses less caustic properties, and acts therefore less injurious on the texture of cot- ton, linen and woolen fabrics. As examples of this property may serve the treatment of lyes with wool or silk, which are actually dissolved by the same, while the soluble glass removes but externally the adhering dirt without any injurious action. The slippery and adhesive consistency of soluble glass acts likewise beneficial in the easy washings and rins- ing with water of the impurities. 220 CEMENTS. There are roany advantages in its applications on wool, silk, cotton and leather; it is stronger than common soap, requires a less quantity, and either hard, soft, cold, or lukewarm water 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 washing and fullmg 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 mili- » tary and other royal institutions and prisons, and also for the paper manufacturers, and their extensive linen establishments ; and instituted experiments as to practicability of a general economical application. In the cotton mills it has proved a saving of 50 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. CEMENTS. 221 The soap manufacturer, who formerly did use rosin for an adulteration or admixture, the cost of which was formerly but two dollars, but rose to 25 and 30 dollars per bbl. of 180 lbs., was obliged to resort to the use of soluble glass in its various forms either as liquid or jelly. Rosin is now again more employed than the sol- uble glass ; not however for the reason that it is better as a sophisticator, but because the soap maker has an idea that 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 w^ith rosin soap, and that tlie admixture of soluble glass is no adulteration, but an improvement, and that it is as economical as rosin soap. 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 mucilage, and is applied on paste board instead of emery or corundum paper, used by cabinet makers and other mechanics for polisliing. 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 ex- posed to much bending. 222 CEMENTS. The glazing or enamelling of culinary vessels, made either for iron or stone ware, the soluble glass is usefully applied in the following manner : — The silicate solution of soda and potasli is mixed with thick lime water, to 100 parts of the silicate add 1 part of lime water, made for 1 part caustic lime to 6 parts of water. The mixture is then evaporated to dryness and reduced to line powder. By dipping first tho objects to be glazed in the liquid silica, the pow- der is then sifted over them ; Avhen 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 slacked lime, which mixture is made into a thin paste with the liquid silicate, and then burnt. This glazing is very durable and resists 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 foe Yarious Cements. Porcelain, Glass and Metals are fastened together when broken, either by the liquid or gelatinous sili- cate by the following method : Heat the object to CEMENTS., 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 fit for use. Fluor- spar 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 powdered 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 paste with the liquid silica. The Athens Marble Cement is composed of carbo- nate of lime, carbonate of magnesia and silica with oxide of iron, and made into a thin liquid and ap- plied to the stone, which, on drying, is permanently fastened to the surface, and protects it from smoke^ dust, and atmospheric agents. Common arid fire brick acquire great strength if the silicate of soda has been employed in the manu- facture, and become indestructible, they are then. CEMENTS. particularly fit for baker ovens, wall and well founda- tions and furnace beds. Glazed paper for apothecarie's use, may likewise be prepared with the soluble glass. Metallio Cement is formed when a mixture of •equal parts of oxide of zinc, per oxyde of manganese and litharge, and made up with liquid silica and marble dust, and applied between the metals to be cemented. An Impermeable Cement Resisting Steam. It is prepared by mixing six parts finely powdered blacklead, 3 parts slacked 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 finly 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. Cement for any foundation wall is made by mixing 1 part of good slacked lime with 3 parts of fine sand, and f of its weight of finely powdered quick lime is added, and made into a paste with the liquid silica ; this mass becomes so hard in 4 days that a piece of sharp iron would not attack it. CEMENTS. 225 The Gypsum and Clay Cement. This cement is very hard, and is prepared by sui intimate mixture with liquid silica, after the gypsum has been calcined, and it is preferred to lime cement for the reason that by the action of lire, it becomes reconverted into lime, which, when the waters from fire engines is brought to bear upon it, expands much and forces out the walls to the destruction of the walls. Hard Adhesive Cement. It consists in mixing 5 parts powdered clay, 2 parts iron fillings, and 1 part of black oxide of manganese, and i part borax made into paste with liquid silica, when dry is very hard, and withstands water. Also a mixture of manganese and zinc wJdte with plaster of paris forms a very hard cement, and has great adhesive capacity. Drain and Gasjpipes 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 lbs. to the square inch, while iron pipes burst under a pressure of 400 lbs. to the square inch. S26 CEMENTS. Cement for Closing Cracks in Stoves, &c. A useful cement for closing up cracks in stove plates, stove doors, etc., is according to a notice of the Scien- tific American, March 12th, 1870, prepared by mix- ing finely 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 fire then becomes the more does the cement melt with its metallic ingredients, and the more completely will the crack become closed. Cement foe a Cistern, Take 10 parts of Plaster of Paris. " 2 Glauber Salts. " 4 " Clay. " 4 Slacked Lime. Made in a plastic cement with the liquid silicate of soda, and before it hardens, add liquid chloride of calcium. I^or sweetem7ig 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 opera- tion onc3 a month. The hest iron cement is composed of calcined plas- ter and iron filings, from each 10 parts, 4 parts oxide manganese, 2 parts slacked lime, made plastic with the liquid silicate of soda. CEMENTS. 227 The most refractory cement is formed from silica, asbestos, plumbago, and soapstone. These materials mixed in certain proportions and made plastic by the liquid silica, form a most valuable cement for locomotive journals and other lubricating purposes, for lining of steam boilers as well as coating, for fi- ling up airholes in iron castings. By the addition of peroxide of manganese, it may be much improved, and serve as a permanent paint, which is fire and waterproof. Besides the cements, such as the Portland, Eoman, Keene's, Parion and Martin's, and those obtained from the Puzzuolanas and Trass, as obtained near Naples, and from the extinct volcanic districts, such as Viva- rais in Central France, at Brihl, near Andernach on the Rhine, and also near Edinburgh in Scotland, and the Rosendale, all of which when mixed with coal cinders, slags and scoria and wood ashes, con- tain more or less soluble alkali, and have a con- siderable effect in hastening the absorption of the moisture, and facilitating the setting of the lime and sand. There are also the burnt clays or terra cotta, and are frequently used as artificial stone, but from their great and unequal contraction, and the facility with which they are acted on by frost, are rarely satisfactory, except treated with soluble glass as has been described. There are also many varieties of concrete now 228 CEMENTS. manufactured in vast blocks and a perfectly solid mass, which replace now the accumulations of rub- bish and loosely aggregated stones, once thought sufficient for filling up intervals between walls of solid masonry, especially in piers, harbors, and other important works, and to which the name concrete has been given, and means a species of rough masonry, consisting of gravel or broken stone mixed with lime, the latter being slaked and immediately put in contact with the gravel. When lime is used that has pre- viously been worked into a paste, it passes by the name of Beton, and the Beton Coignet Building has of late been introduced into this country, and to a great extent substituted for brick and stone. Beton Building. Of all the compositions which in late days have been introduced as a substitute for brick or stone- work, there is not one that presents more attractions as a material than beton. But the use of it is limited to those localities where water-lime can be had at a reasonable price. For, although that admirable cement is about the only one of its component parts that is expensive, yet the proportion used makes the beton more costly than could be wished, notwith- standing its many merits as a building material* There need not be any stone or stone chips used in the making of beton. All that is required to make CEMENTS. 229 a quick-setting and very durable material is, sand three parts ; water-lime, one part ; broken brick, six parts. The water-lime and sand should be well mixed together, dry. Then have as much water thrown on as will make*a moderately stiff mass, when it is to be instantly transferred to the moulds, which are already in their positions on the walls, and the centre to be packed with the broken brick, which, being very porous, will receive the moist cement readily on its broken faces, and help to set tlie whole. The mode of proceeding to construct the courses is by means of moulds easily adjusted and taken apart. They are to be calculated so as to inclose a block of beton of the required thickness of the wall, and of, say, half again that thickness in length. Their height may be ten inches. Thus, if the wall be twelve inches, the block will be the same, and also eighteen inches long by ten inches high. We will proceed to describe the operation of build- ing as carried out in the construction of a beton house at Black Eock, near Buffalo, New York, some years ago. The lines being laid out, the basement was ex- cavated to a depth of six feet, and the trenches for the foundation walls dug out one foot and a half be- low the bottom of the basement. These trenches were two feet and a half wide, that is, three inches on each side wider than the basement wall above them. The basement was, therefore, dug just three 10 230 CEMENTS. inches wider than the plan, all around, and this was done to leave room for the placing of the moulding- boxes with their rods. The bottom of the trenches was made level, and these were Ulled with concrete composed of gravel, six parts ; sand, four parts ; and quick-lime, one !ind a lic^lf part, with sufficient quan- tity of silicate of soda, so as to make the composition plastic. When this mass was well mixed and turned over three or four times, it was thrown into the tren- ches in layers or courses of, say, four inches in depth. Each course was spread over the whole of the founda- tion trenches, until they were all, including those of the foundations of cross-walls, filled. When the sur- face of the basement or cellar bottom was reached, then the whole area was gone over with a coat of gravel ; and over this was poured a creamy mixture of water-lime and sharp river sand, in equal propor- tions, imtil the whole was flush. This was done on Saturday, and on the following Monday the floor was hard enough to walk upon. The basement walls were now commenced in the manner here described. The lines of the walls were carefully laid out, and .angle-moulds placed at each corner, with straight moulds set at equal distances all along. ^ >^ < CEMENTS. 231 A corner mould and three or four straight moulds are sufficient to work with : but the greater the num- ber of moulds the more expeditiously the operation of building goes on. When all was ready, the corner moulds were filled first, and then the other moulds regularly in turn. When all were filled, the moulds were taken apart and set up at other points along the walls ; but sufficient time was given for the beton to become hard enough to admit of being uncovered. The walls being thus gone around, the next operation was to inclose the spaces between the beton blocks, and this was done by using the sides of the moulds, without the ends, and holding them in place by the following means : Two pair of pieces of scantling, say two by three inches each, and two feet long, were set upright at each end of the side-boards, and bear- ing them against the beton blocks. At the middle of their length they were held by the rods and screws used in the moulds ; and their upper ends being kept apart by sticks of the necessary length, the boards were thus clutched and kept in place. These in- closed spaces were now up flush, in the same manner as the moulds, and, by packing and tamping, the con- nections were made so complete as to render the whole a uniform mass. As each course was in this manner completed, the moulds were laid for a new one, taking care to break joint, although no joint waa visible, yet this precaution was taken to avoid any: 232 CEMENTS. continuous joint or point of imperfect connection. Where doors or windows occurred, the moulds were placed correspondingly, on either side of such open- ing ; for it may be observed that there is no neces- sity for the fixing in of the frames until the work is all sufficiently set. However, it is necessary to insert in these moulds, at doors and windows, at the ends which will form the jambs of such, pieces of scant- ling, called stops, say, four inches thick, and in width, sufficient to permit the future frame to rest five or six inches back from the outer face of the wall. Of course, the frame can be set up and these jambs worked up to it, but it is more troublesome and will scarcely make as good a job. The window-sills and caps were provided for in like manner ; and there was. a splay left in the window jambs, by meaus of angu- lar pieces being added to the above-mentioned stops, which gave the required mold to the beton. When the level of the ceiling was attained, the fiooring joists were all set up in their places, and temporary bridgings of plank fixed between every pair, so as to hold the beton, which was thus continued up, making a compact bed for the joists, and effectually prevent- ing the lodgment of vermin. The short boards or pieces here used may be removed when the work i& set, as they will be wanted again on the next floor. In the building we describe they w^ere left in, but it is not at all necessary. CEMENTS. 233 The joists being all flushed up with beton, the floor boards were nailed down and the beton again flushed up to the surface of the floor. The moulds were now placed for the walls of the principal story, which being six inches less than those of the basement, the ends of the moulds were made in accordance with the new thickness, namely twelve inches, and the work went on as before, with the exception of the corners of the main walls, which were rounded by means of blocks of the necessary shape being set in the angle. This rounding off of the walls on the outer corners gives a very neat appearance, without adding to the cost. On the contrary, it economizes the material ; for the thickness at these corners, instead of being greater on the diagonal, is exactly the same as that of the straight walls throughout. In the manipulation of the beton for the walls of the superstructure, it was deemed advisable to pack the front of each mould with a purer or finer coat of cement than that used at the heart, or even at the back, so as to give one uniform face to the outside. This face was carefully troweled into the bed made for it in the mould by working back the coarser beton in which the broken brick was packed. In the top of the first tier of blocks forming the course, an angle mould was laid along and pressed into the fine beton forming the outside face. And on the bottom of the next tier of moulds a cor- responding angle-mould was laid and the beton cast 234 CEMENTS. £rmly around it. And thus every course was treated' The consequence was that the > cincture left on the removal of these moulds produced an effect on the exterior, remarkably like coursed masonry, the course lines being of the > shape, and about two inches wide and one inch and a half deep. Any other sec- tion of cincture can be moulded in to suit another de- sign of building. After each course was uncovered, these sunken mouldings were finished smooth by working a whole mould of the > shape along them, backward and forward. Perpendicular moulds of like shape might have been made to mark out each block, and no doubt would have much improved the appearance of the building. The sunken horizontal courses were carried all around the house and pro- duced a good effect. The next floor was flushed up at the joists precisely in the same manner as the first, or principal floor. The windows and doors were all set in and worked up to. But this, as was before ob- served, is not the better way. The sills and lintels were of oak, but the latter did not show on the out- side. It would be much better to have stone sills and lintels. The partition walls were six inches thick, and were cast in unbroken courses, with the exception of openings for doors. The door-cases were set in and worked up to. Blocks were nailed to the floor at the walls and partitions to receive the base-boards of the apartments, and these blocks were CEMENTS. 235 covered up in the beton. In like manner, there were blocks inserted for nailing finisliings of windows and doors to, and for holding the horizontal slats from which to hang pictures. The roof was a gabled one, of a fourth pitch ; but a Mansard would at this day- be a great improvement. The walls were skim- coated on the inside of the house, and the best rooms were hard finished. Nothing can be easier for the plasterer to make a truly workmanlike job with, for his material is sure to adhere to it. There is little more to add, save tbat the chimnej-flues were all cast round by means of stove-pipes used as moulds, and left in. This is not a good plan, as the stove-pipe will corrode after a time, and it is very difficult, if not impossible, to remove it. It would be better to use a movable cylinder mould with a handle, and have the flue finished smooth in beton. The chimney shafts can be very ornamentally finished with terra cotta caps. To those who can procure water-lime at anything like a reasonable i)rice, we would strongly recommend beton as a particularly applicable mate- rial. It is warm in winter, cool in summer, and at all times dry and healthful. In mixing common lime with it — of course for economy's sake alone — it will be well to bear in mind that, while quicklime swells in slacking, say one-fourth, water-lime, on the contrary, shrinks about a fifth. By experiment on th: limes to be used, exactness can be obtained. And 236 ESSAYS RELATING TO THIS TREATISE. by thus calculating, the two may be, so to speak, dovetailed into each other. — Manufacturer and Builder. Essays Relating to this Treatise. The following essays on the origin as well as functions of car- bonic acid, limestones, alkalies, silica, etc., follow herewith in order to explain, in the first place, what a powerful influence car- bonic acid exercises in the application of soluble or water glass for all purposes of domestic economy, how carbonic acid acts in the sedimentary rocks, and whether derived directly from the atmosphere or from subterranean decomposition, produce the disintegration of carbonate of lime from siliceous substances. The sources of limestones from the ocean bed and coral reefs, and the subsequent formation of various limestone rocks, and application of the same for our purposes ; the origin of the alkalies as are employed in the manufacture of soluble glass. The silica in all its applications for domestic purposes, explain- ing the immense variety of forms as found in nature, and uses in the manufacture for soluble and every other species of glass, and forms an interesting guide for the production of plain and colored glass, and the green sand formation of New Jersey. I. Essay on Carbonic Acid. — By Dr. Lewis Feuchtwanger. " Carbonic acid, the pabulum of the organic and inorganic world." According to the ancient philosophers, the sim- ple bodies or elementary principles from which all the varieties of matter are composed, were but ESSAY ON CARBONIC ACID. 237 four, namely : fire, air, water and earth. This notion, after having for ages formed a part of the creed of the learned, has been completely ex- plained by the light of modern science, though it is not yet extinct among the vulgar. The alchemical writers of the middle ages added to these principles some others, as salt, sulphur and mercury, to which terms, however, they attached ideas very different from those that belong to them at present, and into the nature of which it is not necessary to inquire. Some of the alleged elements of the olden chemists are now known only to exist in imagination, and others are ascertained to be by no means simple sub- stances. Thus air is found to consist of two difierent elastic fluids or gaseous bodies, which may be separa- ted by various processes, and exhibited apart from each other. Water, also, has been ascertained to be a compound, which may be analyzed or decomposed so as to produce two distinct kinds of gases, which may be separately collected, and when again mixed together in proportions, they may be made to form water by their union. Other bodies formerly esteemed simple have yielded to the analytical processes of modern chemistry ; but there is a certain number of substances which, either in the state in which they are presented to us by nature, or as they are procured in various operations by art, have resisted all attempts at further decompo* 538 ESSAY ON CARBONIC ACID, fiition, and which, therefore, as before stated, inuBt be regarded as simple substances. Their number is not very great, amounting to about sixty-three, and it is not unlikely that the future researches of chem- ists may demonstrate some of these bodies to be com- pounds, as we have the latest example in the discov- ery of Graham, who converted the hydrogen from its gaseous form into a metal hydrogenium. At the same time it is probable that additions may be made to the class of elementary substances in consequence of future discoveries, several of those now admitted into this class having become known to us but very recently. Some of those elementary bodies are widely and abundantly disposed throughout the three kingdoms of nature, either alone or in a state of composition, while those appear to be of very rare occurrence, or at least, they have hitherto been met with only in small quantities and in a few situations. The whole of the elementary substances may be arranged in two divisions : the first comprehending those which are not of a metallic nature, and those which are regard- ed as metals, although many exhibit properties differ- ing considerably from those, which are well defined as such, like gold, silver, mercury, iron, lead, &c. The accompanying table shows all the elements. The non-metals are in large capitals, and the metals in small type : ESSAY OX CARBONIC ACID. 239 Hydrogenium Mercury Magnesium Manganese Molybdenum. ., Nickel Niobium NiTROdEN Osmium OXYGEK Palladium Phosphorus Pelopinm Platinum Potassium Ehodium Rubidium Ruthenium. ... Bblenium , Silver Silicon Sodium Strontium SXTLPHUR , Discoverer. Woebler, Germany Basil Valentine Paracelsus knew it in XVI. cen- tury; George Brandt, Sweden. .. SirH. Davy, England Agricola Sir H. Davy, England Ballard, France Stromeyer Bunseu Sir II. Davy Lavoisier established the diamond as carbon ^ Hisingcr, Sweden Scheele, Sweden Vauquclin. Franco Brandt, Sweden Known by the ancients Mosandcr Sheele investigated and discovered, but never separated it Oxide, by Vauquclin, 1797; metal by Wo'liier Known by the ancients As gas, by Cavendish, England Graham Reich found in zinc ore Courtoise, France Tenant Known from early time Mosander Known by the ancients Oxide, by Arfvedson, Sweden, 1818; metal by Brai d Known to the ancients Bussy, France Gahn , Sweden Sheele, Sweden Bergman, Sweden Hatchett Dr. Rutherford, Scotland Tenant Dr. Priestly, England Dr. Wollaston, England Brandt, Hamburg H. Rose Charles Wood. Jamaica Sir H. Davy, England Dr. Wollaston, England Bnnsen Clauss Berzelius, Sweden Known to the ancients Berzelius, Sweden Sir H. Davy Sir H. Davy Natural product Date. o n oc At. Wt. o cu OQ 1828 Al 27.4 2.6 1450 8b 1^2 6.7 1783 As 75 3.7 1808 Ba lo < 1530 Bi 210 9.7 1807 B jj 1.47 1826 Br 80 5.54 1817 Cd 112 8.6 1861 Cs 13;3 1808 Ca 40 1.58 1775 C 12 3.5 1804 Ce 92 1774 CI 35.5 .2454 1797 Cr 52.2 1733 Co 58.7 7 7 Cu 63.5 8.9 1843 D 95 E 112.6 F 19 1.060 1828 Gl 9.8 Au 197 12. 176G H 1 .69 1869 H 1.708 1861 In 35.91 ISOl I 127 4.95 1803 Ir 198 Fe 50 7.79 1839 La 92 Pb 207 11.4 1820 Li 7 .59 Hp 200 13.5 1829 •v.g 24 1.74 1774 Mn 55 7. 17S2 Mo 96 8.6 1775 Ni 5S.7 8.2 Nb 94 1772 N 14 .972 1803 Os 199.2 21. 1774 0 IG 1803 Pa li'6.6 11.3 1669 p 31 2.0 1S46 1741 Pt 197.5 21. 1S07 K 39.1 865 1804 Rh 104.4 11. 1861 Kb 85.4 Ku 104.4 1818 Se 79.5 4.3 Ag 108 10.4 1824 ?i 28 2.49 1807 Na 23 .15 isos Sr 87.5 2.53 S 32 2.0 240 ESSAY ON CARBONIC ACID. Name. Discoverer. Tantalium I (Columbium) j i Tellurium Thallium I Thorium' Tin j Tintanium Tungsten Uranium Vanadium Yttrium | Zinc I Zirconium Ilatchet and Eckoberge, 1801; duced by Berzelins Klaproth, Berlin Crookes and Lane Berzelius, Sweden Known by the ancients. Vauquelin M. M. D''E]huyard, Spain Klaproth, Berlin Sefstrom, Berzelius, and Del Eio Gadolin, Sweden Henkel Berzelius, Sweden '. Date. s ti O cc < 1824 Ta 1S2 1797 Te 12S 6.2 1861 Tl 203 Til Sn 118 7.29 1796 Ti 50 4.3 1781 W 184 17.5 1789 U 120 1830 V 51.8 1794 Y 18.6 1721 Zn 65.2 6.9 1824 Zr 89.6 4.3 OarhoUj one of these elementary bodies, is the most remarkable substance in nature, and enters largely into the composition of most substances be- longing to the animal and vegetable kingdom, and forms also the basis of many of the combustible mine- rals, as bitumen, coal, plumbago, amber. In the form of charcoal, procured by charring or distilling without the access of air, wood, animal, and some other substances, carbon is obtained in a separate state or merely intermixed with small portions of earths or salts. The charcoal used in the various arts and manufactures is commonly prepared on an extensive scale by the imperfect combustion of wood, built up in large piles and covered with turf, or by the distillation of wood in cast-iron cylinders. Lamp- black is also chiefly composed of charcoal, consisting of soot collected from the combustion of the refuse resin obtained in making turpentine. Ivory black is ESSAY ON CARBONIC ACID. 241 another carbonaceous substance, which results from the burning of bones in close vessels. Coke is chiefly composed of charcoal, arising from the distillation of coal, as in the coal gas manufactories. Pure carbon is, however, represented in the diamond. Chemical investigation has proved that the diamond, when ex- posed to a very high temperature, and especially if confined in oxygen gas, will burn like charcoal and exhibiting the same product. This splendid gem, in its natural state, is composed of octahedral crystals, and Sir Isaac Newton ascertained from observing, that it was possessed of high refractive powers and •an inflamable substance. It is brittle, but appears to be harder than any other substance. Hence the powder of the diamond is used for cutting and polish- ing the hardest gems, and the diamond itself, as the most ornamental article of jewelry. How diamond was formed is a matter of enquiry. It certainly ■could not have been produced at a high temperature, because when strongly heated, apart of the air or oxygen, the diamond swells up, and is converted into a black mass resembling coke. Carbon, as commonly procured by distilling wood, is a good conductor of electricity, though a bad con- ductor of heat. It remains unchanged by air or water at common temperature, but when highly heated readily burns in oxygeu,gas or common air. It has the property of destroying the smell and 242 ESSAY ON CAEBONIC ACID. taste of many animal and vegetable substances, and it powerfully resists putrefaction ; so that tainted meat, if covered with new burnt charcoal for a few hours, becomes perfectly sweet. The colors of vege- table substances are also effected by charcoal ; hence it is sometimes added to port wine for the purpose of giving it a tawny hue. Yinegar boiled with it be- comes colorless, and it is largely used in refining sugar, particularly the animal charcoal. Freshly prepared charcoal largely absorbs various gases. This property, however, depends on the texture of the charcoal, and the difierent kinds absorb, in vari- ous proportions, aqueous vapors contained in the air. Carbon unites with oxygen to form three or more compounds, an oxide and various acids. The car- bonic oxide is a gaseous body, and was discovered by Dr. Priestley, and this is produced from the decom- position of the compounds containing carbonic acid, as by the heating in an iron retort a mixture of chalk and charcoal, or of equal weights of chalk and iron or iron filings. The gas resulting from either of these operations may be collected in a jar inverted and filled with water, and then purified by agitating it with lime water. It is destitute of color and taste and has a disagreeable smell, and is highly injurious to animals, producing giddiness and fainting if re- spired when mixed ^^ith atmospheric airs. We have many instances where many families were found suf- ESSAY ON CAEBONIC ACID. 245 focated in the morning, the cause being that they had a coal fire burning, in close apartments, before retir- ing to bed. Carhonio acid, or called fixed air. — It is obtained when the carbonic oxide is mixed with half its vol- ume of oxygen, and exposed in a detonating tube to the electric spark, when an explosion takes place, and carbonic acid is formed equal in bulk to the car- bonic oxide. It is a compound gas, and is formed both by art and nature in a variety of processes. An abundant production of this gas takes place in the combustion of animal and vegetable substances in general ; but the most interesting example of the for- mation of carbonic acid occurs when the diamond is- intensely heated in common air or oxygen gas. This extremely dense and apparently permanent substance under these circumstances becomes wholly converted into carbonic acid, a result which plainly demon- strates it to consist of carbon alone. Carbonic acid^ when wanted for the purpose of experiment, may^ however, be most readily obtained by decomposing the combinations of this acid with alkalies or earths. Thus chalk or marble, when dropped in small frag- ments into dilute sulphuric or hydrochloric acids, will give out abundance of this gas, w^hich may be collected over water ; they, however, absorb a large portion of it, even at common pressures and tempera- tures. ESSAY ON CARBONIC ACID. Carbonic acid gas is destitute of color or smell, but like other acids, it has a sour taste. It is much heavier than common air, and is uninflammable, ex- tinguishing burning bodies which are plunged into it. ■Owing to its great specific gravity, it may be poured from one vessel to another, like a liquid, and will re- main for some time at the bottom of an open jar with- out mixing with the atmospheric air above it. It is poisonous to animals, and cannot be breathed with- out the utmost danger. The famous Poison Valley in the Island of Java, has been visited by travelers, who relate that they took with them two dogs and some fowls to try experiments in the poisonous val- ley. When arriving at the foot of the mountain, and when within a few yards of the valley, they experi- enced a strong, nauseous, suffocating smell. The valley is about half a mile in circumference, and a depth of 30-35 feet, flat bottom, and no vegetation, strewed with some large sized stones, and the whole covered with the skeletons of human beings, tigers, pigs, deer, peacocks, and all sorts of birds. Did not perceive any vapors or any opening in the ground, which appeared to be of a hard, sandy substance. They descended, after lighting a cigar, and assisted by a bamboo, within eighteen feet of the bottom, where they did not experience any difiiculty in breathing, nor did any oflFensive smell annoy them. They then fastened a dog to the end of a bamboo, ESSAY ON CARBONIC ACID. 245 and after the lapse of fourteen seconds he fell on his back ; did not move his limbs, but continued to breathe eighteen minutes. Another one was sent in, and he fell in ten minutes on his face, and continued to breathe for seven minutes longer. A fowl was then tried, which died in one minute and a half. On the opposite side, near a large stone, w^as the skeleton of a human being, who must have perished on his back with the right hand under his head. It is for this reason that the proportion of this gas contained in the air is so very small. Were this proportion much greater than it is, animals, as they are now constituted, could not breathe the air with- out much injury. On the other hand, that growing plants may be able to obtain a sufficient large and rapid supply of carbonic acid from a gaseous mixture which contains so little, tliey are made to hang out their many weaving leaves into the atmosphere. Over the surface of these leaves are sprinkled countless pores or mouths, which are continually employed in separating and drinking in carbonic acid gas. The millions of leaves which a single tree spreads out, and the constant renewal of the morning air in which they are suspended, enables the living plant to draw an abundant supply for all its wants from an atmos- phere already adjusted to the constitution of living animals. (A common lilac tree, with a million of leaves, has 246 ESSAY ON CARBONIC ACID. about 400,000,000 of pores or mouths at work suck- ing in carbonic acid ; and on a single oak tree as many as 7,000,000 of leaves have been counted.) This constant action of the leaves of plants is one of the natural agencies by which the proportion of carbonic acid in the lower regions of the atmosphere is rendered less than it is in the higher regions. As water readily takes up this gas, so it may be made by pressure to absorb a large quantity of it, so is the soda water of the shops, and such is also found in the bowels of the earth, as the mineral springs of all countries which contain also small quantities of saline matters. Carbonic acid has been reduced from a state of gas into that of liquid by compression, Faraday obtained it in this form, by disengaging it from carbonate of ammonia by means of sulphuric acid in a glass tube hermetically sealed, one end of which was immersed in a freezing mixture, and the pressure under which the fluid was formed was estimated to be equal to 36 atmospheres. Carbonic acid may be decomposed by the action of the metal potassium, which having a stronger attrac- tion for oxygen than the carbon has, when heated in carbonic acid, it forms with great splendor, charcoal is deposited and an oxide of potassium is formed. It may also be decomposed by hydrogen and other bodies. ESSAY ON CARBONIC ACID. 24T It is one-balf heavier than commou air. A con- stituent of our atmosphere, which is known to con- sist, in 100 gallons, of 79 gallons of nitrogen and 21 gallons of oxygen, while the carbonic acid is in very small proportion. At ordinary elevations, there are only about two gallons of carbonic acid gas in 5,000 gallons of air, or 1-2500 part of the whole. It increases, however, as- we ascend, so that at heights of 8,000 or 10^000 feet^ the proportion of carbonic acid is nearly doubled. Even this increased quantity is very small, and yet its presence is essential to the existence of vegetable life on the surface of the earth. This dependance ap- pears more striking the more precise our ideas be- come as to the absolute quantity of the carbonic acid which the entire air contains. The whole weight of the atmosphere is about fifteen pounds to the square inch, and at this the carbonic forms somewhat less than 120 grains, containing about 33 grains of car- bon. Notwithstanding plants are continually suck- ing in this gas by their leaves, and the operation goes on so rapidly, that were the entire surface of the earth dry land, and under cultivation, crops as we generally reap from it, would contract and fix the whole of the carbon in the form of vegetable matters in the short space of twenty-two years. Were this to happen, vegetation would cease. Such a catastrophe is prevented by the constant restoration of carbonic ESSAY ON CAEBONIC ACID. acid to the air through the increasing operation of preservation causes, which may be summed up under the following heads : 1. The trees of the forest yearly shed their leaves, and, in some countries, their bark. Through the in- fluence of the weather, these waste portions decay and disappear, restoring again to the atmosphere a portion of the same carbon which the living tree had previously detracted from it during the period of their growth. The yearly ripening herbage, also, and every plant that naturally withers on plain or liill, the grass of the burning prairie, and the timber of inflamed forests, with all that man consumes for fuel and burns for other uses, every form of vegetable XQatter, in short, when exposed to the action of air or fire, returns more or less quickly to the state of car- bonic acid, and disappears in the invisible atmos- phere. Thus what is yearly withdrawn from the air by living plants is so far restored again by those which naturally perish, or which are destroyed by the intervention of man. 2. But man himself and other animals assist in the same chemical conversion. They consume vegetable food with the same final result as when it perishes by natural decay or is destroyed by the agency of fire. It is conveyed into the stomach in the form in which the plant yields it. The green herb, the perfect seed, and the ripe fruit are eaten and digested. Then ESSAY ON CARBONIC ACID. 249" forthwith they are breathed out again from the lungs= and skin in the form of carbonic acid and water^ Let us follow the operation more closely. The leaf of the living plant sucks in carbonic acid from the air, and gives off the oxygen contained in this gas. It retains only the carbon. The roots drink in water from the soil, and out of this carbon and water, the plant forms starch, sugar, and: other substances. The animal introduces this starch sugar into its stomach, and draws in oxygen from the atmospliere by its lungs. With these mate- rials it undoes the previous labor of the living plant,, delivering back again from the lungs and the skin both the starch and the oxygon in the form of car- bonic acid and water. The circle begins with car- bonic acid and water, and ends with the same sub- stances, the same materials. The same carbon, for example, circulates over and over again, now float- ing in the invisible air, now forming the substance of the growing plant, now of the moving animal, and now again dissolving into the air, ready to begin anew the same endless revolution. It forms part of a vegetable to-day, it may be built into the body of a man to-morrow, and a week hence it may have passed through another plant into another animal. What is mine this week is yours the next. There is, in truth, no private property in ever-moving matters^ 3. Yet all the carbonic acid which is removed from ^50 ESSAY ON CARBONIC ACID. the air by the agency of plants is not immediately restored by the circulation above described. Two larger wheels revolve to make up the deficiency. 4. It has been shown that when plants die and decay, are burned in the air, or are eaten by animals, the carbon they contain is delivered back again to the atmosphere in the form of carbonic acid. But all the plants produced yearly over the whole earth are not so resolved into gaseous substances in any given time. In all parts of the world, and during all time, some portions of vegetable matter have escaped this total destruction, and have been buried beneath the surface of the earth to be preserved in the solid form for an indefinite period. With such comparatively indestructible forms of vegetable matters we are fami- liar, in the peat bogs of Scotland and Ireland, some- times from 50 to 100 feet deep, and in the submarine forests which are seen in so many parts of our inland shores. We are still better acquainted with them, however, in the vast deposits of coal which a kind Providence long ago brought together and covered up. What is and has been thus collected and gradu- ally buried would necessarily cause a constant dimi- nution in the small quantity of carbonic acid con- tained in the air were there no natural means in operation for making up the yearly loss. The means we are most familiar with for repairing this loss are those which man himself brings into operation. At ESSAY ON CARBONIC ACID. ^51 a certain period in his history, half-civilized man dis- covered the use of coal. At a more advanced period, he found out how to dig deep and hollow out mines in search of it ; and at a still later period, how to em- ploy it for a thousand beneticial purposes. In burn- ing coal, we cause its carbon to unite with the oxygen of the air, and to disappear in the state of carbonic acid. We restore it to the atmosphere again in the state in which it existed there, perhaps, a million of years ago, when it was sucked in by the growing plants, and, in the form of vegetable matter, afterwards buried beneath the earth's surface. In raising and consuming coal, therefore, we are, to a certain extent, undoing and counteracting the -yearly lessening of the carbon, in the air, which appears to come from the yearly covering up of a portion of vegetable mat- ter. The 200,000,000 tons of coal which are now yearly consumed throughout the globe, produce about 600,000,000 of tons of carbonic acid. How far this quantity serves to compensate for what is constantly buried up agaiu, it is impossible to estimate. It must be acknowledged, however, that the coal fires we burn are an important subsidiary agent in pro- moting the circulation of carbon on the globe. 5. Again, within the bosom of the great seas tiny insects are at work, upon which nature has imposed, in addition to the search for food and the care of 352 ESSAY ON CARBONIC ACID. their offspring, the perpetual labor of building new houses. The common shell-iish of our coasts toil con- tinually for defence as well as for shelter, rep airings enlarging and renewing their own dwelling places; and as they die, each drops its shell as a feeble con- tribution to the beds of shelly limestone, which are everywhere forming at the bottom of our deep seas. In more southern waters, again, still humbler insects- build up massive coral walls, thousands of miles in extent, which now skirting along coast lines, and now encircling solitary islands, bid defiance to the angriest storms. And then, too, as they die, genera- tion after generation, leave in rocky beds of coralline limestone an imperishable momorial of their exhaust- less labors. These rocks contain, chained down in a seemingly everlasting imprisonment, two-fifths of their weight of carbonic acid. This has been all withdrawn, either directly or indirectly, from the at- mosphere, and thus, through the rock, forming living things it contains, the sea must ever be drinking in and storing up the carbonic acid of the air. The same process has been going on almost con- tinuously since the world began. Yast coral reefa lie buried beneath our beds of coal and mountains of thick ribbed shelly limestone have been lifted from ancient seas before these other reefs were formed. The labours of marine animals, therefore, like the burying of vegetable matter must throughout all ESSAY ON CARBONIC ACID. 253 time have been causing a daily lessening of the ab- solute quantity of carbonic acid in the atmosphere, which some other natural operation has meanwhile been making compensation for this constant removal. But the earth herself breathes for this purpose. From cracks and fissures, which occur in vast nnmbers over the surface of the earth, carbonic acid issues in large quantities, sometimes alone and sometimes along with springing waters, and daily mingles itself with the ambient air. It sparkles in the springs of Carlsbad and Selzer, rushes as if from subterranean bellows on the table land of Paderborn, astonishes travellers in the Grotto del cane, interests the geologist in the caves of Pyrmont and among the old caves of the Eifel and is terrible to man and beast in the fatal " Yalley of Death", the most wonderful of the wonders of Java, and besides, it doubtless issues still more abundantly from the unknown bottom of the expand- ed waters which occupy so large a proportion of the surface of the globe. From these many sources, con- tinually flowing into the sea, carbonic acid is and has been daily supplied in place of that, which is daily withdrawn to be buried in the solid limestones of the globe. Did we know after what lapse of time the earth would again breathe out what is thus daily en- tombed, we should be able to express in words how long this slovely revolving secular wheel requires fully to perform one of its immense gyrations. 11 254: ESSAY ON CARBONIC ACID. Carbonic acid gas rises from the earth in an elastic form, or assumes many successive varieties of plant and animal forms, is finally buried in the earth again in a state of blackened fossil plants or beds of solid lime- stone. Carbonic acid, as has already been stated, is very plentifully disengaged from springs in almost all countries. (The writer drank, in California, in a fissure of the celebrated marble quarry at Suisan City, 1,000 feet above the level, ten cups of water, in which the carbonic acid gas was so abundant and free that the water was unable to take up any more.) It is, however, particularly abundant near active or extinct volcanoes. This elastic fluid has the property of decomposing many of the hardest rocks with which it comes in contact, particularly that numerous class in the composition of which felspar is an ingredient. It renders the oxide of iron soluble in water, and con- tributes to the solution of calcareous matter. In vol- canic districts these gaseous emanations are not con- fined to springs, but rise up in the state of pure gas from the soil in various places, as already observed in the Grotto del Cane, near Naples, and the prodi- gious quantities now annually disengaging from many parts of the Limagna d'Auvergne, where it appears to have been developed in equal quantity from time immemorial. As the acid is invisible, it is not ob- served except an excavation be made, wherein it im- ESSAY ON CARBONIC ACID. 255 mediately accumulates, so that it will extinguish a candle. There are some springs in this district where the water is seen bubbling and boiling up with much noise in consequence of the abundant disengagement of this gas. The whole vegetation is affected, and many trees, such as walnut, flourish more luxuriantly than they would otherwise do in the same soil and climate, the leaves no doubt absorbing the carbonic acid. It is found in springs rising through the granite near CI aremont, as well as in the tertiary lime- stone of the Limagne. Near Claremont, a rock belonging to the gneiss for- mation in which lead mines are w^orked, has been found to be quite saturated with carbonic acid gas, which is constantly disengaged. The carbonates of iron, lime and manganese are so dissolved that the rock is rendered soft and the quartz alone remains nnattacked. Not far off is the small volcanic cone of Chaluzet, which once broke up through the gneiss and sent forth a lava stream. The effect of carbonic acid as a. chemical agent, both as commonly present in atmospheric air and as more abundantly occurring in such localities as those above described, must depend on the nature of the rocks and other bodies with which it may come in contact. It may thus cause the decomposition of granite, gneiss, and other feldpathic and micaceous substances by combining with the potash, soda and 256 ESSAY ON CARBONIC ACIJ>. lithia which enter into their constitution. On the contrary, when it encounters lime or magnesia it may contribute to the production of new rocks. The disintegration of granite is a striking feature of large districts in Auvergne, especially in the neigh- borhood of Claremont. Dolomieu called this decay " la malady du granite," and the rock may with pro- priety be said to have the rot, for it crumbles to pieces in the hand. The phonomenon may, without doubt, be ascribed to the continual disengagement of carbonic acid gas from numerous fissures. The chemical action of carbonic acid, as it exists in the usual state of the atmosphere near the earth's sur- face, though much more gradual, and, therefore, less noticed than were it copiously evolved from the water or soil as in volcanic countries, is yet suffici- ently powerful to produce a manifest effect on the structure of large masses of granite and rocks of analogous composition. In the western parts of Great Britain, where primitive formations prevail^ granite masses frequently occur, which, from their peculiar forms, received the celto Cymric appellations af lagon, talmon and kistoaers, and were by the an- tiquarians long regarded as works of art of Druidical origin; bat there rocking stones, rock basins, cheese- rings, and altars are now generally admitted to be blocks of granite which have acquired their respective forms in consequence of superficial decomposition or ESSAY ON CARBONIC ACID. 25T disintegration. Devonshire is the locality for these odd figures, which, Dela Beche remarked, looked more like the remains of some huge building or hattlement than the effect of cleavage and decompo" sition, which it is. Granite is not generally regarded as a stratified rock, like gneiss and mica slate ; but it is a fact well known to the workmen who are employed in quarry- ing and cutting it, that it has what they term a grain^ or that it will split in one or more directions more easily than in others. This, doubtless, is owing to the arrangement of the mineral bodies of which it is composed, and especially the feldspar, the decompo- sition of which must essentially aid the process of disintegration, and determine in a great degree the direction in which it takes place. The protracted action of atmospheric air, and also of water, appear to act jointly as a destructive and formative or constructive power ; likewise the more rapid and violent operation of streams and torrenta assist in dissolving and wearing away solid surfaces in the situation, and depositing beds of transported matter in another ; and the detritus of rocks and of organic bodies have been removed by the agency of water from the higher parts of a country, and serving to form new tracts of land. Such catastrophas are common to most countries, and if a rock so detached or weathered be limestone, there is not unfrequently « 258 ESSAY ON CARBONIC ACID. a reconsolidation of the parts l^y means of calcareous matter deposited by the water that percolates through the fragments, and which dissolves a portion of them. At Nice, the fractured surface thus reunited is so hard, that if it occur on a line of road, it must be blasted by gunpowder for removal. The same recon- solidation gives ample example upon the limestone hills of Jamaica, and at the cliffs of Milk river at that place. The feldpar contained in granite is often easily de- composed, and when this is effected, the surface fre- quently presents a quartzose gravel. D'Aubuisson mentions that in a hollow way which had been only Bix years blasted through granite, the rock was en- tirely decomposed to the depth of three inches, and the granite country of Auvergne and Eastern Pyrenees, felspar is frequently so much decomposed that the traveller may imagine himself on large tracts of gravel. The most striking example of the detrition of solid rock by the agency of water is ex- hibited at the Falls of Niagara. The water at these falls is divided by a small island, which separates the river into two cataracts, one of which is 600 yards, and the other Y50 yards wide. The height of the fall is from 150 to 160 feet. It is estimated that 670,000 tons of water are dashed with inconceivable force against the bottom, wearing down the adjacent rocks. Since the banks of the cataract were in- ESSAY ON CARBONIC ACID. 269 habited by Europeans, they have observed that it is progressively shortening the distance of the falls from Lake Erie. When it has worn down the intervening calcareous rocks, the upper lake will 'become dry land, and form one extensive plain or valley, sur- rounded by rising ground, and watered by a river or small lake, which will occupy the lowest part. In this plain, future geologists may trace successive strata of fresh water formation covering the subjacent ancient limestone. The gradual deposition of minute earthy particles, or the more rapid subsidence of mud from sudden inundations, will form distinct beds in which will be found the remains of fresh water fish, vegetables and quadrupeds. Prof. Henry says : " The descent of the country from Lake Erie to On- tario is principally by a step, not at the falls, but at Lewistown, several miles below. In reviewing the position of the Falls, and the features of the country around, it is impossible not to be impressed with the idea that this great natural race-way has been formed by the continued action of the irresistable current of the Niagara, and that the falls, beginning at Lewis- ton, have, in the course of ages, worn back the rocky strata to their present site. The deep chasm through which the Niagara passes below the falls is nearly a mile wide, with almost perfect mutual sides. The bed of the river below the falls is strewed with huge fragments of rocks hurled down by the cataract. '260 ESSAY ON CARBONIC ACID. The retrogration of the waterfall, owing to the de- struction of the surface over which it takes its course, is said to have amounted to nearly fifty yards during the last forty years. If the excavation always pro- ceeded at the same rate, it must have required about 10,000 years for the formation of the whole ravine ; and it would take up more than 30,000 years from the present time before the channel would be worn backward to Lake Erie ; but if it retroceded 1 inch a year, which would make 8f feet a century, 380,000 years." The great gorge of the Colorado, which is 300 miles long and 3-6000 feet deep, and hundreds of feet of the depth being much of the distance through granite, has probably taken the same length of time as the Niagara retrocession, and at the close of the mesozoic period or reptilian age, which was the era of the culmination and incipient decline of two great types in the animal kingdom, the reptilian and mol- luscan, and remarkable as the era of the first mamals, birds and fishes. Before proceeding further of the functions of car- bonic acid in the inorganic world, let us make a few remarks respecting the distinctions between animals and plants, in order to show how near the organic bodies are related to the inorganic, and that carbonic acid may probably have an important agency in this all important work. Since the discovery that the ESSAY ON CARBONIC ACID. 261 spores (or seed cells) of some algae have locomotion like animalcules, and that there are unicellular loco- motive plants (the diatoms, etc.) Some have thought that the two kingdoms of life were blended together through their inferior species. But the fact is that they are diverse throughout ; the opposite but mutu- ally dependent sides or parts of one system of life. The following are some of their distinctions : 1. Plants excrete oxygen, a gas essential to animal life ; animals excrete, in respiration, carbonic acid, a gas essential to vegetable life. 2. Plants take inorganic material as food and turn it into organic ; animals take this organic material thus prepared (plants) or other organic materials made from it (animals), finding no nutriment in in- organic matter. 3. Plants passing from the unicellular state by growth lose in power, becoming usually fixed ; ani- mals, in the same change or in development from a germ, increase in power, augmenting in muscular force ; and also in the case of species above the low- est grade in nervous force, like an ant is a one ant- power, a horse a one horse-power, whence an animal is a self-propogating piece of enginery, of various power, according to the species. 4. The vegetable kingdom is a provision for the storing away or magazining of force for the animal kingdom. This force is acquired through the sun's 262 ESSAY ON CARBONIC ACID. influence or forces acting on the plant, and so pro- moting growth. That of starch, vegetable fibre and sugar is a state of concentrated or accumulated force^ and there is also a magazining of force in a still more concentrated or condensed state. There are thus five states of stored force in nature — three in inorganic, the solid^ liquid and gaseous ; and two in organic, the vegetable and animal. The animal type diff'ers from the vegetable, (though not all animals from plants,) in this, that while the latter has the superior and inferior polarity of single growth — the stem grow- ing upward and the root downward — the former has the anterior and posterior or cephalic and aiiticephalic polarity connected with a well developed nervous system.. The radiates among animals are allied in this respect to plants, being animal representatives of the vegetable radiate type ; and this is the ground of the subdivision of the animal kingdom. The following are the two grand subdivisions in groups in nature, the first mentioned being the infe- rior, the other the superior. The latter is also the more typical group, or that in which the idea of the type is more fully represented : a. Life in general — 1, vegetable; 2, animal king- dom. h. Vegetable kingdom — 1, cryptogams or flowerless plants ; 2, phanerogams or flowering plants. c. Animal kingdom — 1, the flower-like type, in- ESSAY ON CARBONIC ACID. 263 eluding radiates; 2, the true animal type or cephalized species, that is, those having a head or anterior and posterior polarity with bilateral symmetry, including mollosks, arti- culates and vertebrates. d. Sub-kingdom of mollusks — 1, the flower-like type, including the bryozoans closely like flowers, the brachiopods generally attached by stem or pedicles, and ascidiaiis, also often attached ; 2, the true molluscan type, includ- ing acephals, cephalates and cephalopods. e. Sub-kingdom of yertebrates — 1, water verte- brates, including tishes ; 2, land vertebrates, including reptiles, birds and animals. f. Class of crustaceons — 1, entomostroceons ; 2, raalacostroceons. g. Class of reptiles — 1, amphibious; 2, true rep- tiles. A. Class of mammals — 1, marsupials or semiovipar- ans ; 2, nonmarsuphial or typical mammals. The great question of the day is, where can we draw a strait line between organic and inorganic bodies, for if we ever succeed to produce these organic matters, fat, starch, or tibrine from inor- ganic substances, the problem would be solved. From a lecture by Dr. Loew, of the College of the City of New York, referring to this great difficulty, and to the important place carbonic acid assumes in 264 ESSAY ON CARBONIC ACID. the organisms, the followmg extract must be highly interesting : " Confessing that we cannot state positively how -the first organic being was formed from inorganic matter, nevertheless we must conclude from conse- quence that it ^vas formed by natural forces. When we see that the vegetable can produce organic matter from inorganic substance ; when we see the animal being taking this organic matter of the vege- table up, and during the process of its life connecting in the very same inorganic combinations from which the vegetable builds up its body ; when we see this inlinite construction, destruction, and reconstruction, we remark, as one of the first conditions, that the vegetable world existed previous to the animal world. Hence arises the question. How was the first organ- ized vegetable world formed ? There are possibilities directly from inorganic matter or from previously formed organic matter. Above all, let me ask here attention to the difierence between the words ' or- ganic ' and ' organized.' The chief part of an organ- ism consists of carbon, hydrogen, oxygen, and nitro- gen ; water and mineral salts form the remainder. These four most important elements combine in an infinite number of proportions, and these combina- tions are of such an extremely complex order as are never to be found in the inorganic world. An or- ganic combination is the first condition for an organ- ESSAY ON CARBONIC ACID. 265 ized body, and organic combinations form the step from inorganic matter to organized beings. Two possibilities may have existed : either organic matter was formed from inorganic by natural forces, pre- vious to the formation of the first cell, or in the other case, the cell, during its formation, formed also the organic combination necessary for its life from mine- ral salts, carbonic acid, and water. In the first case, the spontaneous generation has the same plasmogony ; in the second, autogeny. Theodore Saussure was the first who stated the fact that the carbonic compounds in the vegetables derive their carbon from the car- bonic acid contained in the air, and their hydrogen from the matter. Liebig then stated that the nitro- gen of the plants comes from the ammonia contained in the soil and in the atmosphere. We see, there- fore, the body of the vegetable, no matter how com- plicated its structure and its organization may be, is built up chiefly from carbonic acid and water — three inorganic combinations of a simple constitution. By a process of reduction, complicated organic radicals are formed, combining themselves to numerous bodies. Among these are sugar, fat and albumen. As organic chemistry must be considered as an off- spring of this century, it was, of course, considering its tender age, not possible until a few decades ago to prepare an organic body synthetically from its €!lements ; therefore the hypothesis came in vogue 266 ESSAY ON CARBONIC ACID. that there exists an especial power, the vital power.. It was long considered as an impossibility to prepare artificially, from inorganic matter, such combinations as may occur in the vegetable and animal body. The death-knell of the dogma of vital force was tolled in the year 1828. In this year the German chemist^ Woehler, prepared, synthetically, the first organic combination. Woehler, in attempting to prepare eganate of ammonia, got, in evaporating a mixture of eganate of potassium and sulphate of ammonia, a body of an entirely difterent character to the salt he was seeking for. The atoms arranged themselves in another form, and this body presented itself exactly the same as that which is found in animal urine, named urea. This was the first step on a new road, and so rapid was the progress of organic chemistry, so rapidly was it advancing, that now we can count them by the hundreds. Dr. Loew then gave instan- ces of some of these combinations. Thus hydrogen and carbon, united in the voltaic curve, produce the hydrocarbon acetyline — the root of numerous organic combinations — until, with hydrogen, it produces de- fiant gas ; the cyanide of this gas, boiled with potassa^ gives succinic acid ; this treated with brimstone, and then with potassa, gives malic and tartaric acid ;. malic acid heated gives fumaric. But malic, tartaric and fumaric are organic acids occurring in a great number of vegetables ; they can thus be artificially ESSAY ON CAKBONIC ACID. 26T prepared from the elements. From acetyline ben" zol may be produced ; from benzol, benzoic acid, the root of a great number of organic combinations^ which can all be artificially prepared from benzoic acid, as oil of bitter almonds, gallic acid, hypurie acid, &G. Sulphur and carbon may be united; the bisulphide of carbon, treated with iron filings and water, gives formic acid, which occurs in the ant and in the nettle ; formic acid, treated with potassa, yields- oxalic acid, which is found in many plants. By treat- ing oxalic ether with sodium amalgam, we obtain disoxalic and malic acid and a kind of sugar, all or- ganic substances. Dr. Loew added to these instances- numerous others, in which organic substances, such as fat, sugar, and alcoliol, were formed by chemical processes from inorganic bodies. He then continued : These organic bodies which I have mentioned here form only a small part of the numerous organic com- binations which can be prepared artificially from the elements in the laboratory ; but, simultaneously, I must confess that there is much more to do than has been done. For example, gum-starch, quinine, strychnine, cannot yet be artificially prepared, but there is not the slightest doubt that chemistry will solve all these problems in coming time. Further, it must be mentioned that the ways of the chemist in the laboratories are different from the ways of nature. The chemist has strong acids at his disposi- ^68 ESSAY ON CARBONIC ACID. tion ; not so with nature, for she works only with the reducing power of the sunlight. That cannot as yet Be imitated, although we can often reach the same result in a laboratory. The history of chemistry, however, bids us to hope that this problem will yet be solved. When this great problem finds its solu- tion, we will obtain, probably some light, as to how, from carbonic acid, water and ammonia, organic matter was formed hundreds of thousands of years ago, when the first cell became endowed with life. In every case we had different conditions in those in- finitely remote ages — conditions more favorable for spontaneous generation, as there was a very warm and wet atmosphere rich in carbonic acid, with a mineral surface more liable to change, and different in appearance to what it is now-a-days. Therefore, it is probable that those first cells had quite a differ- ent charactsr, as we imagine very liable to change and to different developments. Many experiments have been made to produce, artificially, cells, infuso- ries, or fungi, and this question seems to be satisfac- torily solved." In regard to the chemical relations of our globe, Dr. T. Sterry Hunt, in his lecture on primeval chemis- try, throws much light on the functions of carbonic acid exercised upon our globe, and cannot do better than to make an extract of his remarks : After explaining the astronomical parts and solar ESSAY ON CARBONIC ACID. 269 system, he says, in reference to the history of this earth, that there were no chemists who had an eye, except the eye of its great All Seeing One, to inves- tigate the marvellous phenomena ; but the chemist of the present day has to look to the rocks, water and air, and to their origin. Our earth was once a luminous mass of vapor, passing through a stage in which it was self-luminous like the sun, until it finally became cool to such a point that it liquified and became at last solid. The next question is, did the earth become solid first at the circumference or at the center ? This is important from more than one point of view, and has been in- vestigated by astronomers, physicists, and chemists, and it seems pretty clearly proved that the earth, if not solid to the center, must have a crust several hundred miles in thickness. And it is probable that if the cooling commenced at the center, that at least the surface would be covered with a thin layer of liquid matter, which, on cooling, would give an un- even surface to the primeval globe. So far as the chemistry of our planet is concerned, we have to deal only with this outer layer, all the various elements of which must have existed either in that crust or in the atmosphere which then surrounded it. We form a good idea of this primeval crust, if we suppose the elements, rocks, air and ocean to be brought together at the intense heat wliich tlien existed. Under such 270 ESSAY ON CARBONIC ACID. conditions the lime, magnesia, alkalies — would all unite into combination with silica and alumina, while the atmosphere would contain chlorine, sulphur, carbon and hydrogen, together with oxygen and nitrogen. This would form on the one hand a slag- like siliceous mass, and on the other hand an atmosphere charged with acid vapors, yielding all the chlorine, sulphur and carbon in the form of acids, and the water in the form of steam mixed w^ith nitrogen and oxygen. The weight of the atmosphere would be immense, and under its pressure water and the less volatile acids would be liquified at the high tempera- ture, and these acid waters would collect in the de- pressions of the earth's crust, where they would immediately decompose the silicates, separating the silica and forming sulphates and chlorates of the al- kalies — lime and magnesia. This solution would form first, sea water, and the action would continue till these affinities were satisfied. Then commenced a new chemical process, the action of air and water upon the exposed portions of the earth's crust, con- verting the silica into clay, with carbonates of lime, magnesia, and soda through the action of the carbonic acid of the atmosphere. The soda carried by rains to the sea, decomposes the lime salts, forming car- bonate of lime and sea salt. The process is still going on, though more slowly, from the small amount of carbonic acid in the air, and causing the decay in the ESSAY ON CARBONIC ACID. 271 hearts of granite rocks. We have thus explained the generation of silica or quartz of elay and of lime- stones, the principle elements of sedimentary rocks. Every clod of clay represents granite rocks decom- posed, and an amount of limestone and sea salt^ formed from the waters of the ocean. In this way the air was freed from carbonic acid, and fitted for the support of animal life. Besides this, the vege- tation removed large portions of carbonic acid, re- placing it by oxygen, and the formation of limestone directly diverted still greater amounts of carbonic acid, whose presence must have rendered the early atmosphere unfit for the higher forms of life. The presence of carbonic acid in the early atmosphere serves to explain the higher temperature then prevailing, which permitted the growth of tropical plants within polar circles. Wc know that a portion of carbonic acid, such as then existed in the air, while it would not prevent the passage of the sun's rays would impede the radiation of obscure heat from the earth's surface, and thus tend to keep up a summer temperature. The effect of this carbonic acid would be like the glass of an orchard-house in preventing the escape of heat. Thus carbonic acid exerted also an important part in many other chemical processes; then active at the earth's surface. Besides deposits, formed by chemical processes, mechanical operations were forming at the earth's surface a great amount ESSAY ON CARBONIC ACID. of sandy and clayey rocks, which make up the bulk of the stratified forms. Although the interior of the earth has been regarded as solid, it is notwithstanding doubtless intensely heated, and thus is explained the increase of temperature as we go below the surface. The cooling of this center, once rapid, is now very slow indeed from the thickness of the overlying sedi- ment. The effect of this heat upon the deeply buried sediment has been to crystallize them, and convert them into metamorphic rocks. To this class belongs granite, once looked upon as a primitive rock. We have now evidence that granite is in all cases a secondary rock, derived from sediments crystallized through the agency of water and heat. In the quartz of granite are often found small cavities, partly filled with water, which are so many small thermometers showing the temperature at which the granite was crystallized. Pressure, which increases the melting point of rock when exposed to fires, greatly favors the dissolving power of heated water, so that we may suppose that the lowest* strata of sediment and often adjacent portions of the primal nucleus being per- meated with water, under great heat and pressure, became softened and yielding. From this softened zone came all eruptive rocks, and in it are to be found the causes of volcanoes whose various products are generated by the action of heat upon the varied elements of deeply buried sedementary strata. The ESSAY ON LIMESTONES. 2Y3 theory which ascribes volcanic products to the sup^ posed uncooled liquid center, fails entirely to account for the great diversity in composition of these pro- ducts, all of which, wherever found, are represented in rocks of aqueous origin. The distribution of niodern vocanoes shows them to be intimately con- nected comparatively recent accumulations ot sedimentary rocks ; entire absence of volcanic pheno- mena over the eastern part of this continent is thus explained. II. 0?i Limestones: their Origin and Functions. The early geologists were impressed with the theory of the origin of all limestones; that is, was due to organized beings or substances, and the reason advanced by them was because the quantity of lime- stone in the primary strata bore a much smaller pro- portion to the silicious and argillaceous rock in the secondary, and because testaceous animals were so rarely found in the ancient ocean, and furthermore that the quantity of calvareous earth deposited in the form of mud or stone is always increasing, and that as the secondary series far exceeds the primary in this respect, so a third series may hereafter arise from the depth of the sea, which will exceed the last in the proportion of its calcaceous strata. Some con- clusions were drawn from this assertion that lime 274 ESSAY ON LIMESTONES. may probably be an animal product combined by the powers of vitality from some simple elements, and that every particle of lime that now enters into the crust of the globe, may possibly in its turn have been •subservient to the purposes of life by entering into the composition of organized bodies. Lime is contained in the ocean and is plentifully secreted by the testacea and corals of the Pacific, and must have derived either from springs rising up in the bed of the ocean or from rivers fed by calca- reous springs or impregnated with lime, derived from -disintegrated rocks, both volcanic and hypogene and the greater proportion of limestone in the more modern formations, or compared to the most ancient may be explained, for springs in general hold no argillaceous and but a small quantity of siliceous matter in solution, but they are continually substract- ing calcareous matter from the inferior rocks. The constant transfer therefore of carbonate of lime from the lower or older portions of the earths' crust to the surface must cause at all periods and throughout an indefinite succession of geological epochs a prepon- derance of calcareous matter in the newer or con- trasted with the older formations. It has been urged that we discover in the ancient rocks the signs of an epoch, when the planet was uninhabited and when its surface was in a chaotic condition. The opinion however that the oldest of the rocks now visible may ESSAY ON LIMESTONES. 2Y5 be the last monuinents of an antecedent era in which living beings may already have peopled the land and water, has been declared to be equivalent to the assumption that there never was a beginning to the present order of things, no argument can be drawn from premises in favor of the infinity of the space that has been filled with worlds, and if the material universe has any limits, it then follows, that it must occupy a minute and infinitessimal point in infinite space. So if in tracing back the earth's history, we arrive at the monuments of events which may have happened millions of ages before our time, and if we still find no decided evidence of a commence- ment, yet the arguments from analogy in support of the probability of a beginning remains unshaken, and if the past elevation of the earth be finite, then the aggregate of geological epochs, however numer- ous, must constitute a mere movement of the past, a mere infinitesimaal portion of eternity! We know that it is not only the present condition of the globe, which has been suited to the accommo- dation of myriads of living creatures, but that many former states also have been adapted to the organiza- tion and habits of prior races of beings. The dispo- sition of the seas, continents and islands, and the climates, have varied, the species likewise have been changed ; yet they have all been so modelled on types analogous to those of existing plants and 276 ESSAY ON LIMESTONES. animals, as to indicate tlirongliout a perfect harmonj of design and unity of purpose. To assume that the evidence of the beginning or end of so vast a scheme lies within the reach of our philosophical inquiries, or even of our speculations, appears to be inconsis- tent with a just estimate of the relations which subsist between -the Unite powers of man and the attributes of an infinite and eternal being. The peculiar position of lime in the system of nature, is that of a medium between the organic and inorganic, world. Carbonate of lime is soluble in water which holds a little carbonic acid in solution, and is found in river, marine and well waters. It is made inta shells, corals, and partly into bone, by animals, and then turned over to the inorganic world to make rocks. Lime is therefore the medium by which organic beings aid in the inorganic progress of the globe ; for the greater part of limestones have been made through the agency of life, either vegetable or animal. Lime, which is the oxide of the metal cal- cium, is commonly called quicklime, forms com- pounds with silica or silicate, with carbonic acid, the carbonate or carbonate of lime, which is the material of limestones, with sulphuric acid the sulphate of lime or gypsum. Lime also unites with phosphoric acid, forming phosphate of lime, the essential material of bones, a constituent also of other animal tissues. Like the ESSAY ON LIMESTONES. 2^7 carbonate, this phosphate is afterwards contributed to the rock material of the globe, and is one sonrce of mineral phosphates. Calcium is one of the nine elements which are the prominent constituents of rocks, viz., oxygen, silicon, aluminium, magnesium, calcium, potassium, sodium, and carbon, making up 977-1000 of the whole crust. The limestones of the giluric and later ages have nearly all been made through the wear and accumulation of shells, crinoids and corals, or the calcareous relics of whatever life occupied the seas. The great limestone formations of existing coral seas are modern examples of the process. It has been the subject of curious specula- tion whence the coral polypifers and testaceous mollusca can obtain the vast quantities of carbonate of lime which they secrete to form the envelopes by which they are preserved. It has been considered more than probable that they have the extraordinary faculty of producing lime from simple elements. Some seem disposed to impute its origin in the same manner to the influence of vital energy in combining elementary bodies^ and it follows that the quantity of lime on the surface of the eartli must be progressively increasing, unless it be supposed that other natural processes are regu- larly taking place for the decomposition of calcareous earth, or rather of the metallic base calcium, 12 278 ESSAY ON LIMESTONES. Mr. Lyell, however, sees no reason for supposing ^that the lime now on the surface or in the crust of the earth may not, as the silex and aluminum, or any other mineral substance, have existed before the first organic beings were created, if it be assumed that the arrangement of the inorganic materials of our planet proceeded in the order of time, the intro- duction of the first organic inhabitants, and adds, in reference to the abundance of carbonate of lime furnished by springs which rise through granite, that if the carbonate of lime, secreted by the testaceous corals of the Pacific, be chiefiy derived from below, and if it be a very general effect of the action of subterranean heat to subtract calcareous matters froai the inferior rocks, and to cause it to ascend to the surface, no argument can be derived in favor of the unaggressive increase of limestone from the mag- nitude of coral reefs, or the greater proportion of calcareous strata in the more modern formations. A constant transfer of carbonate of lime from the inferior parts of the earth's crust to its surface, would cause throughout all future time, and for an indefinite succession of geological epochs, a preponderance of calcareous matter in the newer as contrasted ^ith the older formations. The rock, formed under the surface of the sea originated either from depositions or from chemical precipitation ; those of the former class are numerous, ESSAY ON LIMESTONES. 279 including most of the stratified rocks which inclose ssa-shells, fragments of corals, and other exuviae of bones of marine animals. Among those of the better class, some geologists have reckoned even granite, and Deluc states in that- respect that the strata of granite were evidently produced by chemi- cal decompositions from a liquid, and form the most ancient monument of the action of physical causes on our globe ; however the origin of granite as well as that of all other unstratitied rocks, has been ascribed mostly to igneous fusion and consolidation. Most of the calcareous rocks containing marine shells must have been produced under the influence of chemical affinity, and of this nature are the forma- tions which are occasionally observed to take place on the sea coasts. Collections of perfect and broken shells and corals are sometimes consolidated by the precipitation of calcareous and ferruginous matter, constituting banks or beds of considerable extent. Such masses, containing shells, occur in various parts of the shores of Great Britain. Similar conglome- rates, including both shells and corals, are not uncom- mon around some of the islands in the West Indies. At Guadaloupe human bones have been found imbedded in a rock of this kind, whence were obtained two imperfect human skeletons, one pre- served at the British Museum, and the other in the Paris Museum, and from the occurrence of these ^BO ESSAY ON LIMESTONES. bones, and otlier circumstances, may be inferred the comparatively modern origin of the rock in question. The Florida Keys abound in deposits of shells in various states of disintegration and subsequent union by cement. Among the marine formations there are few more curious or interesting than coral reefs and islands, which to a certain extent are constructed by different kinds of polypiferous zoophytes ; and they are very numerous, mostly belonging to the genera Mean- drina, Coryaphillia, and Astrea, particularly the latter. All of them are minute animals, for which the coral tubes serve as habitations. It has been supposed that the coral rocks descend in perpendicu- lar columns to the bed of the ocean, and cover millions of acres of the Pacific. So great is the extent, that the inhabitants of Disappointment Islands and those of Duff's Group pay visits to each other by passing over long lines of reefs from island to island, a distance of six hundred miles. Many islands which were visited by Capt. Kotze- bue have several groups of coral islands arranged in a circular or oval form, with openings among them which afforded access to the interior basin. These islands seemed to be only the upper portion of ridges of unequal height, on the inside of which, toward the basin or lagoon, where there is still water, the smaller and more delicate kinds of polypes carry on ESSAY ON LIMESTONES. 281 tlieir operations, while the stronger species live and work on the exterior margin of the bank, against which a great surf usually breaks. These creatures leav^e off building as soon as their structures reach such a heigiit as to be left almost dry at the lowest ebb of the tide. A mass of solid stone is seen, com- posed of shells of molluscs, and when with them broken off prickles, and fragments of coral cemented by calcareous matter. The ridge is raised by frag- ments of corals thrown up by the waves, till it becomes so high as to be covered only by high tides at certain seasons. Masses of the stone thus formed are sometimes separated and thrown upon the surface of the reefs, so as gradually to augment its elevation. Tlie rate of growth of the common branching Madre- pore is not over one and a half inches a year. Other branches are open. This would not be equivalent to more than half an inch in height of solid coral for the whole surface covered by the Madrepore ; and as they are also porous, to not cover over three-eighths of an inch of solid limestone. But a coral plantation has large bare patches without corals, and the coral sands are widely distributed by currents, part of them to depths over one hundred feet, where there are no living corals. Not more than one-sixth of the surface of a reef region is in fact covered with grow- ing species, which reduces the three-eighths to one- sixteenth. Shells and other organic relics may 282 ESSAY ON LIMESTONES. contribute one-quarter as much as corals. At the outside the average upward increase of the whole reefground per year would not exceed one-eighth of an inch, j^ow some reefs are at least two thousand feet thick, which at one-eighth of an inch a year cor- responds to 190,000 years. If the progressing subsidence essential to the increasing thickness were slower than the most rapid rate at which the upward progress might take place, the time would be propor- tionally longer. Coral formations are most abundant in the tropical Pacific, where there are two hundred and ninety coral islands, too numerous to mention. A distinction exists between coral islands and coral reefs ; the first are isolated coral formations in the open sea, and the second are banks of coral bordering other lands or islands. It has been already stated that the tropics are the hotbed for coral formations ; the limiting temperature of reef forming cdrals is ggo They do not flourish where the mean tem- perature of any month of the year is below that degree. Certain tropical coasts are exempt from coral reefs, for the following reasons : the cold extra- tropical oceanic currents, as in Western South America ; muddy or alluvial shores, or the emptying of large rivers ; for coral polyps require clear sea water and generally a solid foundation to build upon. Also the process of volcanic action destroys the life of a coast ; also the depth of water on precipitous ESSAY ON LIMESTONES. 283 shores, for the reef corals do not grow where the depth exceeds one hundred feet. Beyond that depth til ere are no growling corals, except some kinds that enter but sparingly into the structure of reefs, the largest of which are the dendrophylliae. The rock forming the coral platform and other parts of the solid reef, is a white limestone, made out of corals and shells: its ramification is like that of ordinary limestones. In some parts it contains the corals imbedded, but in others it is perfectly com- pact, without a fossil of any kind, only an occasional sliell. In no case is it chalk. The compact, non- fossiliferous kinds are found in the lagoons or shel- tered channels, the kind made of broken corals on the sea shore side, in the face of the waves ; those made of corals standing as they grow in sheltered waters, where the sea has free access. The ])rincipal kinds of coral rock consist in, 1. A fine grained, compact, and clinking lime- stone, solid and flint-like in fracture as any Silurian limestone, and with rarely a shell or fragment of coral. This is a calcium variety, and wdien coral reefs and islands have been elevated, it often makes up the mass of the rock exposed to view, it is a puzzle how to account for the absence of the fossils. 2. A compact colite consisting of rounded concre- tionary grains, and generally without any distinct fossils. 284 ESSAY ON LIMESTONES. 3. A rock equally compact and hard with No. 1, but containing imbedded fragments of corals and some shells. 4. A conglomerate of broken corals and shells, with little else, very firm and solid ; many of the corals several cubic feet in size. 5. A rock consisting of corals standing on the solid earth, the interstices filled in with coral sand, shells and fragments. In general, the rock is exceed- ingly solid, but in some instances the interstices are but loosely filled. All these corals, when alive in w^ater, are covered throughout with expanded polyps, emulating in beauty of form and colors the flowers of the land. Besides corals and shells, there are also some kinds of calcareous vegetation called nullipores, both branching and incrusting in form, which add to the accumulation. They grow well over tlie edge of the reof, in the face of the breakers, and attain consider- able thickness. The waves in their heavier movements, sweeping over the coral plantations, may be as destructive as winds over forests. They tear up the corals, and by incessant perturbation reduce the fragments to a great extent in to sand, and the debris thus made, and ever making, are scattered over the bottom or piled upon the coast by the tide, or swept over the lower parts of the reef into the lagoon. The corals keep ESSAY ON LIMESTONES. 285 growing, and this sand and the fragments go on accumulating, the consolidation of the fragmental material makes the ordinary reef rock. Thus, by the help of the waves, a solid reef structure is formed from the sparsely growing corals. Where the corals are protected from the waves, they grow up bodily to the surface, and make a weak open structure instead of the solid reef rock, or, if it bo a closely branching species, so as to be firm, it still wants the compactness of the^reef that has been formed amid the waves. According to their posi- tion, " there are fringing or barrier reefs, the first are attaclied ^directly to the shore, while the others are like artificial moles, separated from the shore by a channel of water. The thickness of a coral formation is very great, sometimes thousands of feet; the instances are quoted that no bottom was found at 6,000 fe3t ; at the Fejees, 2 to 3,000 feet. Fringe reefs form the origin for the Atolls, like the Menchikoff, as explained by Darwin, which are high islands consisting of two clusters of summits, like Mani and Oahee in the Ilawaian group. It has been st ited that one of the principal sources of the lime- stone formation is formed. Shells and corals, which form extensive beds and acquire a texture as firm as any marble, and by watching the process of accumu- lation, from the growth of corals and the wear of the waves, that the remains of these corals form a com- 286 ESSAY ON LIMESTONES. pact bed ; and we infer from tliis great phenomenon that if we meet with a limestone over this continent containing remains of corals or shells, that the ancient limestone was as much a slowly formed rock made of corals or shells as the limestone of coral seas. From Hirsch's new Journal " The Arts " the following Extract is made with reference to the reef- building coral. The variety of compact and branching corals far exceeds description : 120 species are inhabitants of the Red Sea alone, and an enormous area of the Tropical Pacific is everywhere crowded with the stupendous works of these minute agents, destined to change the present geological features of the globe, as their predecessors have done in the remote ages of its existence. Four distinctly different formations are due to the coral-building polypes in the Pacific and Indian Oceans, namely : lagoon islands or atolls, encircling reefs, barrier reefs, and coral fringes — all nearly con- fined to the torrid zone. An atoll is a ring or chaplet of coral, enclosing a lagoon or portion of the ocean in its centre. The average breadth of that part of the ring which rises above the surface of the sea is about a quarter of a mile, often less, and it is seldom more than from six to ten or twelve feet above the waves ; hence the ESSAY ON LIMESTONES. 287 lagoon islands are not visible, even at a very small distance, unless covered by the cocoanut, tbe palm, or tlie pandanus, which is frequently the case. On the outside, the ring or circlet slopes down for a distance of one or two hundred yards from its edge, so that the &ea gradually deepens to about twenty -live fathoms, beyond which the sides of the ringe plunge at once into the unfathomable depths of the ocean, with a more rapid descent than the cone of any vol- cano. Even at the small distance of some hundred yards, no bottom has been reached with a sounding- line a mile and a half long. All the coral in the exterior of the ring, to a moderate depth below the surface of the water, is alive; all above it is dead, being the detritus of the living part washed up by the surf, which is so heavy on the windward side of the tropical islands of the Pacific and Indian oceans, that it is often heard miles olF, and is frequently the first warning to seamen of their approach to an atoll. The outer margins of Maldave atolls, consisting chiefly of nullipores and porites, are beaten by a surf 90 tremendous that even ships have been thrown, by a single upheaval of the sea, high and dry on the reef. The waves give innate vigor to the polypes by bring- ing an ever-renewed supply of food to nourish them, and oxygen to support life; besides, uncommon energy is given and maintained by the heat of the 288 ESSAY ON LIMESTONES. tropical sun, which gives them power to abstract enormons quantities of solid matter from the water to build their strong homes — a power that is efficient in proportion to the energy of the breakers which furnish the supply. On the margin of the atolls, close within the line, where the coral is washed by the tide, three species of nuUipores flourish ; they are beautiful little plants, very common in the coral islands. One species grows in thin spreading sheets, like a lichen ; the second, in strong knobs as thick, as a man's finger, radiating from a common centre ; and the third species, which has the color of peach blossoms, is a recticulated mass of stiff branches, about the thickness of a crow's quill. The three species either grow mixed or separately, and although they can exist above the line of the corals, they require to be bathed the greater part of each tide ; hence a layer two or three feet thick, and about twenty yards broad, formed by the growth of the nullipores, fringes the circlet of the atolls and protects the coral below. The lagoon in the centre of these islands is supplied with water from the exterior, by openings in the lee- side of the ring, but as the water has been deprived of the greater part of its nutritious particles and inorganic matter by the corals on the outside, the harder kinds are no longer produced, and species of more delicate forms take their place. The depth of ESSAY ON LIMESTONES. 289 the lagoon v^aries from fifty to seventy fathom or lest^, the bottom being partly detritus, partly live coral. In these calm, limpid waters, the corals are of the m )st varied and delicate structures, and the most c'larming and dazzling lines. When the shades of evening come on, the lagoon shines like the milky way, with millions of brilliant sparks. The microscopic medusa and Crustacea, in- visible during the day, form the beauty of the night, and the sea-feather, vermillion in day-light, now waves with green })liosphorescent light. This gor- geous character of the sea-bed is not peculiar to the lagoons of the atolls — it prevails in shallow water throughout the whole coral-bearing regions. We have other materials of organic origin which have been formed into rocks, and which are generally divided in four groups, such as, 1. The calcareous rocks from which the limestones have been formed, namely, corals, shells, crinoids, which have a specific group of '2,428. 2. The silicious, or those which have contributed to the silica of rocks, and may have originated flints, such as, the microscopic siliceous shields of the infusoria called diatoms, which are now regarded as plants; J, the microscopic siliceous spicula of sponges. 3. The phosphatic, or those which have contributed phosphates, especially the phosphate of lime, as 290 ESSAY ON LIMESTONES. bones, excrements, and a few shells related to the lingula. Such excrements are called coprolites, as those of birds, when in large accumulations guano. 4. The carbonaceous, or. those which have afforded coal and series of plants. Among the calcareous rocks, we have also an uncrjstalline limestone and a crystalline, 1. The massive, which, as has previously been mentioned, as being formed from shells and corals, ground up by the action of the sea and afterwards consolidated; The colors are dull gray, bluish, brownish to black, its composition is usually the same as that of calcite, carbonate of lime, except that impurities, as clay or sand, are often present. They vary in texture, from an earthy looking limestone to a very compact semi crystalline one, and passes gradually into a crystalline. 2. Magnesian or Dolomitic Limestone, which con- sists of carbonate of lime and magnesia, but it is not distinguishable in color or texture from ordinary limestone. Most of our American limestones are, magnesian. 3. Hydraulic Limestone. It is an impure or earthy limestone, containing some clay, and affording quick- lime, and thence the water cement is formed. 4. Ooietic Limestone, a rock consisting of minute concretionary spherules, and looking like the petri- fied row of fish. ESSAY ON LIMESTONES. 291 5. Chalk is a white earthy limestone, which leaves a trace on a board. 6. Marl, a clay, composed of a large proportion of carbonate of lime ; and it is called shell marl if it consists largely of shells or corals. T. Shell Limestone is a rock consisting entirely of shells or corals. 8. The Birdseye Limestone is a compact limestone which has crystalline points disseminated through it. 9. The Travertin is a massive but porous lime- stone formed by depositions from springs or streams^ holding carbonate of lime in solution, or bi-carbon- ate. Such a rock abounds on the river Avino, near Tivoli, and is used there as building material. 10. Stalagmite, Stalactite, depositions from water trickling through the roofs of limestone caverns, from pendent calcareous cones and cylinders from the roofs, which are called stalactite, and incrusta- tions on the floors which are called stalagmite ; they are usually translucent. The crystalline limestone comprehends the granular limestone, such as the statuary marble, which has a granular texture from white to gray color. The calcareous deposits in the thermal springs have been mentioned, and have fur- nished food for speculation as to their origin and cause of their deposit. We find some hot springs which deposit siliceous matter, and some calcareous. The Geysers of Iceland contain siliceous earths in solution 292 ESSAY ON LIMESTONES. aud deposit them on cooling ; these deposits extend over an area of about half a mile in diameter, and from the depth of a cleft near the great Geyser, the siliceous matter appears to be more than twelve feet in thickness. The hot springs of Furnas, in the vol- <3aaic district of St. Michael, one of the Azores, large quantities of silex, enveloping grass, leaves and other vegetable bodies, some of which are still flowering, in the island are seen, frequently forming horizontal strata, siliceous stalactites two inches long, and cov- ered with small brilliant quartz crystals. The hot springs of Arkansas, in the Ozark Mountains, form a district of extinct volcanoes ; tliey have furnished the author most exquisite specimens of quartz crystals in groups for his own cabinet, and excited the admira- tion of the scientific and curious world when h? exhibited them at the London Exhibition in 1851, and the variety of forms, as well as the sizes and par- ticular appearance, cannot be excelled. The thermal springs of Primarkoon and Loor- goothe, in the East Indies, contain besides silica various salts of soda. The Travertin is by no means confined to loca- tions where limestone districts are known, but occurs indiscriminately in all rock formations. In Au- vergne in France, w4iere the primary rocks are desti- tute of limestone, springs abundantly charged with carbonate of lime rise up through the granite and ESSAY ON LIMESTONES. 293 grass. In the valley of the Elsa, which skirts the Appenines in Italy, are innunerable springs which have thrown down such calcareous precipitates that the w^hole ground in some parts of Tuscany is coated with Travertin, and sounds hollow under foot. A most striking instance of the rapid deposit of carbon- ate of lime from thermal w^aters may be observed in the hill of San Yignone, on the high road between Sienna and Home, a large mass of Travertin de- scends the hill, from the point w^hence the spring issues to the bank of the Iliver Orcia, a distance of 250 feet, forming a mass of varying thickness, but sometimes 200 feet in depth, and on the other side of the hill a similar deposit extends about half a mile, in parallel strata, one of which is fifteen feet thick and constitutes excellent building stone. The hot springs of Wachita, before mentioned, have likewise large deposits of travertin, forming escarpments along the borders of the stream, into which the hot springs descend. . Among the beds of the Potsdam period, the mag- nesian limestone strata of the Quebec group contain numerous fossils, and thus show that they are marine and that they have the origin of whatever life occu- pied the seas. The extensive magnesian limestones of the Mississippi Valley have the same composition and are similar in compactness ; the natural inference is that they were also of organic origin. But over 294 ESSAY ON LIMESTONES. extensive regions they do not contain a single fossil. Yet it is to be remembered that the sea, which grinds pebbles and sand and makes fine sandstones, may also grind shells and make an impalpable limestone. This is abundantly exemplified in coral regions, for a large part of the limestone there made of corals and shells is as compact and imfossiliferons as the magne- sian limestone in question. The only other mode of origin is by chemical depo- sition. This could not have taken place in the open seas, for, owing to the oceanic currents, the waters have a remarkable uniformity of composition, and no local deposition can take place. It requires, there- fore, an elevation above the sea and the existence of calcareous mineral springs, and springs on a wonder- fully vast scale, for a formation as extensive as the magnesian limestone of the Potsdam period. Such a condition of things is improbable. Moreover, the depositions would have a structure wholly unlike that of the magnesian limestone. Whoever has seen the travertin beds of Tivoli, which are the largest of the chemical calcareous deposits formed in the present era, will appreciate the wide distinction between the mass made up of a series of incrustations, curving with all sorts of fantastic irregularities, and the dense even-grained limestone of the calciferous epoch. The oolitic structure of part of this limestone has a paral- lel in the oolitic coral rock of Key West, which is also without imbedded corals or shells. ESSAY ON LIMESTONES. 295 It is curious to reflect that if the bottom of the equatorial seas, wliere atolls abound, were upraised aud laid dry, we should behold mountain peaks arid ridges composed fundamentally of volcanic, gra- nitic and other rocks, on which tabular masses of limestone would repose. Some of these calcareous cappings would be continuous over an area three miles, others above 300 miles in circumference, while their thickness might vary from 1,000 to 10,000 feet or more. They would consist principally of corals and shells — in some places entire, in others broken. In the lower regions of the same continent, and be- tween the high table lands or mountain ridges, there would often be no contemporary deposits, or where exceptions occurred to this rule the calcareous strata would differ in their nature as much as in the species of fossils which they enclosed from the tabular masses of coral. It has been observed that the softer corals^ when they decompose in the lagoon, are resolved into a white mud, which, when dry, is undistinguishable from common chalk' and inference may be drawn that a recent cretacrous formation may now be in progress in many parts of the Pacific and Indian oceans. It is, however, more than probable that lime^ which is generally contained in sea water and secreted so plentifully by the testacea and corals of the Pacific, may have been derived either from springs -296 ESSAY ON LIMESTONES. rising up in tlie bed of the ocean, or from rivers fed by calcareous springs, or impregnated with lime de- rived from disintegrated rocks, both volcanic and hypogene ; and if this be admitted, the greater pro- portion of limestone in the more modern formations, as compared to the most ancient, will be explained, for springs in general hold no argillaceous, and but a small quantity of siliceous matter in solution, but they are continually substracting calcareous matter from the inferior rocks. The constant transfer, therefore, of carbonate of lime from the lower or older portions of the earth's crust to the surface, must cause ^it all periods, and throughout an indefinite succession of geological epochs, a preponderance of calcareous matters in the newer, as contrasted with the older, formations. The chalk of which allusion has just been made, baving their origin likewise in the lagoons where the corals have been converted into mud, belongs to the tertiary strata called the cretaceous or chalky group and is but a limestone or carbonate of lime. Al- though usually soft, this substance passes in many localities by a gradual change into a solid stone used for building, the stratification is often obscure, except where rendered distinctly alternating layers of flint. These layers are from 2 to 4 feet di extant from each other and from 3 to 6 inches in thickness, occasionally in continuous beds, but more frequently in nodules. ESSAY ON LIMESTONES. 29r No doubt exists but what the chalk was formed in an open sea of some depth, but how so large a quantity of this peculiar white substance could have accumulat- ed over an erea many hundred miles in diameter and some of the extreme points of which are distant more than 1000 geographical miles from each other, is of the greatest interest and its derivation from the decay of corals and shells has given rise to many philo- sophical investigations. The most difficult problem is the origin of the flint in the chalk, whether it occurs in isolated nodules or continuous layers. It seems that there was originally siliceous as well as cal- careous earth in the muddy bottom of the cretaceous sea, at least when the upper chalk was deposited. Whether both these earths could have been alike supplied by the decay of organic bodies, may be a matter of speculation. The flints which is contained as nodules in the chalk are distributed in layers through it like the hornstone in the earlier limestones; they are more or less rounded and often assume fan- tastic shapes; sometimes they resemble rolled stones, but in fact all are of concretionary origin. The exterior of the nodules for a little depth is frequently white and penetrated by chalk, proving that they are not introduced boulders or stone but have origi- nated where they now lie, and we attribute the parallel disposition of the flints layers to successive deposition. The distances between the layers must have been 298 ESSAY ON LIMESTONES. regulated by tlie intervals of precipitation, each new mass forming at the bottom of the ocean a bed of pulpy fluid, which did not penetrate the preceeding bed on which it rested, because the consolidation of the last has so far advanced as to prevent snch inter- mixture; it remains, therefore, a singular phenome- non not yet satisfactorily accounted for. Perhaps, as the specific gravity of the siliceous exceeds that of the calcareous particles, the heavier flint may have sunk to the bottom of each stratum of soft mud. How far and wide this mud has been scattered by oceanic currents may be seen by the area over which the white chalk preserves a homogenous aspect, that we can hardly find an analogous deposit of recent date ; chalk is found from the north of Ireland to the Crimea, a distance of 1,140 geographical miles, and from the south of Sweden to Bordeaux, about 840 geographical miles. The chalk cliffs of the English Channel form one great continuous mass on both sides, in the neighborhood of London and Paris basin. Chalk forms one of the rocks of the cretacious period. It is not found in America, but the creta- cious limestone of this formation comprises very extensive beds, and is divided into two great epochs — 1, that of the earlier cretaceous, and 2, the epoch of the later cretaceous ; they extend from New Jersey to South Carolina, along the Gulf borders, and ESSAY ON LIMESTONES. 299 through a large part of the Western Interior region, over the slopes of the Rocky Mountains, from Texas northward and far into the Colorado region, on the west of British America and Arctic Sea, but they are unknown on the Atlantic borders north of New York. The rocks comprise beds of sand, marl, clay, loosely aggregated shell limestone, and compact limestone, and the sandy layers are predominating, and are of va- rious colors ; white, gray, reddish and dark green, and though sometimes solid, they are often so loose that they may be rubbed to pieces in the hand, or worked out by a pick and sliovel. Layers of potters' clay occur in the series. The marl of New Jersey and elsewliere, which is a dark green sandy variety and forms very extensive beds, is called Greensand ; is a green silicate of iron and potash, with a trace of phosphate of lime, and this makes it highly valuable for fertilizing purposes. The cretaceous formation has a thickness in New Jersey of 400 to 500 feet ; in Alabama, 500 to 600 feet ; in Texas, about 800 feet ; and in the region of the upper Missouri, 2,000 to 2,500 feet. The upper or later cretaceous period, comprises the beds on the Atlantic and Gulf borders and in New Jersey, while the lower are re})resented in the West- ern Interior region, including Texas. The cretaceous beds of Europe have been divided into : 300 ESSAY ON LIMESTONES. 1. The lower cretaceous, including — England, the lower greensand, 800 to 900 feet thick, and in other regions beds of clay and limestone, sometimes chalky. 2. Tlie middle cretaceous, including in Eng- land — the clayey beds or marls called gault, 150 feet thick ; and J, the upper greensand, 100 feet thick. 3. The upper cretaceous, including in England the beds of chalk, in all about 1,200 feet. It consists of — the lower or gray chalk or chalk marl without flint ; J, the white chalk containing flint ; ; Absorbs Phos^phorus, 68; Absorbs Suli)hur, 68. Aluminates of Lime, Hydration of, 67; and Calcareous Clay, 71. Alumocalcite, 37 American Limestone Hydraulic Mortar, 87 Ametiiystine Quartz, 26 Ammonia, 173 Analcime, 39 Analysis of Portland Cement, 73; Rondout Hydraulic Lime, T5 ; of Sap, 164. Ancient Ceiiiont, 96; Law for Lime, 98; Law for Sand, 98; Mortar Hardnes.s, 95. Angular Grains for Mortar, 84 Anhydrous Silicates, 39 Animal and Vegetable Albumen, 153; Acts like a Ferment, 153. Anti-Kust Paint, 53 Apophyllitc 12S Aqu.irium Cement, 218 Argillaceous Limestone, 68; Strata, 104; Sandstone, 37. Arkansas Hot Springs, 292 Arrangement of Kocks, 305 Arsenic, White, 40 Artificial Gems, 341 ; H3'draulic Ce- ment, 94. Artificial Stone, 58; Author's, 56; Explanation of, 123 ; Ransome's, 54; Silicilication of, 128; To Ex- cel Nature, 58. Artificial Sulidiate of Barvta, 138; Its Proportion, 138. Asbestos Cement, 53 Ash and Oak, Decrease in Weight, 148 Asphalt : Compound for Wall Damp, 82; Pavement, 179; Cost of. 1^1; Utterly Impervious to Water, 181. Athens Marble Cement, 223 Atolis formed by Fringe Reefs, 285 Authors Artificial Stone, 56; Pre- paration, 142; Process, 142. Aventurine 27 Babel Quartz, 34 Banded Agate, 29 Bariila, 19 Barium, Chloride of, 138 Barrel l.ining, 52 Barvtn, 138; A Fine Paint, 87; En- amel, 138; Paint, 133. Basic Efl'ects of Carbonate of Lime, 114 Belgian Pavement 178 Berlin Museum Painted by Kaul- back, 128 Berzelin's Cement, 78; Discovery, 21 Beton Building, 228; Process of, 229 Beton Coignet Concrete, 182 ; Great Durability, 182; Its Cost, 182. Bisilicatcs, 89 Bittern of Salines, 51 Blanc Fix, 189; Its Manufacture, 139; Mixed with Starch andDex- terine, 139; Not Dilitorv upon Health, 139. Bloodstone Cement, 133 Boerhave's Account, 19 Bohemfan Glass, 13 Bone Dust 142 Bookbinders' Pa3te,a Substitute for, 221 Borax 145 Bottle Glass, 18 Boucherie's Process, 145 Bouilly's Cement, 79, 105 Bracannot's Ink, 183 Brewery Cement, ... 214 Bricks, Absorption of, 209 ; of Roman Walls, 62. 15 350 INDEX. Bridges of Concrete, 216 Broadway Pavement, 196 Brooklyn Navy Yard, 15, 141 Brown and Miller Pavement, 204; Similar to Nicolson, 204. Buhrstone, 33 Building. Marerial, 49; Timber Se- cured, 142 ; Wooden, 127. Burnett's Process, 145 Cachelong, 35 Cadmium, aulphuret, 126 ; Yellow, 138 Calcareous Clay and Aluininate of Lime, 71 ; Deposits in Thermal Springs, 291 ; Rocks Divided into Uncrystalline and Crystalline, 290 ; Ten Varieties, 290. Calcium is one of the Nine Elements and Forms 997-1000 of the Earth's Crust, 277 Calcination of Earth, 43; Flint, 38; Hornstonc, 38 ; Quartz, 33; Sand, 48 Cannel Coal Tar contains 7 per ct. PhenicAcid, 174 Cannon Balls Preserved, 16 Cap Quartz 26 Captain Kotzebue's Description of Coral Islands, 280 Carbon, 240; Character of, 249. Carbonate of Lime, Basic Elfect« of, 114; Silico, 16; Soda, 314. Carbonic Acid Essay, 236 ; Gas, 140 ; Produced in Quantity of, . . 251 Carlsbad and Selzer Springs, 253 Carnelian, 29 Cat's Eye Quartz, 27 Cause of Hardening, 115 Cause of Damp Walls, 85 Caustic Lye, 20 Cavernous Quartz, 26 Cellar Cement, 53, 76 Cement against Steam, 224; An- cient, 96; Aquarium, 213; Asbes- tos, 53; Athens Marble, 223; Berzelin's, 78; Bloodstone, 133; Bouilly's, 79, 105; Brewery, 214; Cellar, 53; Cistern, 77, 226; Clay, 225; Drain and Gas Pipe, 225; Emery, 133; Fire, 76 ; Fire Brick, 53 ; Fire Proof, 223 ; For any Sub- stance, 78; For Dry Walls and Cellars, 76; For Glass and Metals, 222 ; For Iron and Stone, 71 ; For Metals, 222; Foundation Wall, 224; Glass, 78; Gypsum, 225; Hamelin's, 78; Hamilton's, 105; Hard, 134; Hard Adhesive, 225 ; Impermeable, 224 : Iron, 77, 226 ; Keene's, 66; Kuhlman's, 78; Lute's, 77; Malt House, 214; Manganese, 183; Martins, 66; Meaning of, 73; Metallic, 224; Most Adhesive Insoluble, 212; Most Refractory, 227; Parian, 66; Peasley, 116; Plaster, 66; Portland, 65; Reese's, 78, 105; Roman, 65, 104; Roofing, 53; Solidifying Property, 102 ; Sort I's, 108 ; Steam Resisting, 77 ; Stinde's, 96; Stone. 74; Stove, 226; Strong Iron, 116; Terra Cotta, 79, 105; Various, 222 ; Water Tanks, 214 ; with Chloride Calcium, 49 ; Zinc, 224 Chabasite, 39 Chalcedony Quartz, 28 Chalk, a Substitute for Lime, 57; Flints in, 20; Flints of, 32 : Hard- ening of, 17; origin of, 296; Silici- fication. 58. Characteristic Features of Chalk, . . 323 Character of (Carbon 249 Character of Glass, 336 Character of Potassium, 310 Charcoal Application, 41 Charring. Not Consuming, 141 Cheap White Paint, 126 Cheapest Lubricator, 212; White- wash, 913; Yellow-wash, 213. Chert, 32 Chloride Calcium, 17, 48 Chloride of Barium, 138 Chloride of Lime, 140 ; of Iron, 48. Chimes of Barrels Filled, 250 Chrome Red, 138 Chrysoprasc, 29 Circular of Uses, 50 Cistern Cement, 77, 226 Cisterns, Protection of, 210 Classification of Glass, .331, 333; of Rocks of New York City, by Dr. Stevens, 303. Clay Cement, 225; Clay and Chalk, 142 Clay, Per Centageof, 102; Siliceous, 75; test, 38. Cleavage Quartz, 23 Coal Tar Recommended, 143 Coating of Stone, 207 Cobalt Blue 138 Cochineal Ink, 133 Cold Water poured over the Mass, . 42 Colored Agate, 29 ; Jelly. 43. Colors of Quartz 24 Colors Syringed on Painting, 135 Combustion, Protection against,... 140 Coming Pavement, 185 Commodore Perry, 16 Common Opal, 35; Sandstone, 37. Composition of Doebereiner, 15 Composition with Silicates, 106 Compounds of Oxygen, 38; of So- dium. 813. Compound Water Glass, 16 Concrete, 66 ; Beton Coignet, 182 ; Fiske, 200 ; for Bridges, 216 ; for Floors, 216 ; for Wall Damp, 81 ; Pavement, 179. Condensation of Silica, 119 Conglomerate Quartz, 33 Concretionary Quartz, 24 Consolidation of Shells and Corals by the Precipitation of Calcareous and Ferrugenous Matter, 279; Florida Keys an Example, 280. INDEX. 351 Constituents of Glass, 329 ; of Quartz, 22, 26. Conversion of Silicate of Lime, 134 Copperas, Solution of, 144 Copper Scales Additional, 43 Copper, Sulphate, 145 Corals Covered with Expanded Polyps, 284 : Kcseuiblinp Forms and Colors of P'iowt-rs, 284 ; Waves Destructive to, 284. Coral Formations, Thickness of, 285; Certain TroDical (Coasts Ex- empt. 282 ; Tropics the Hot Beds for, 282. Coral Islands Described by Captain Kotzebue, 280; in the Pa- cific, 282, 290. Coral Plantation with Bare Patches, 281 Coral Platform, 283 Coral Koef Building as Described by Hirsch, 286: One Hundred and Twenty Species, 286. Coral Keef, Two Thousand Feet Thick, 2*^2; Corresponds to 190,000 years, 282. Coral Reef Kock, Consolidation of Fragments Form, 285; Frins;ing or Barrier Reefs Formed, 285. Coral Kocks Cover Millions of Acres, 280; Descends in Perpendicular Columns, 280; Divided into Five Kinds, 283. Cost of Asph.alt Pavement, 181 Cost of Boton Coignet Concrete, . . 182 Crab Grass, 19 Cretaceous Belt, 105; Period, 299. Cross-Ties, 51 Protection of, 210. Crypto-Crystalline Quartz, 25 Crystal ¥(nm Quartz, 23 Crystal Glass 13 Culinarv Vessels, Euanielling of, .. 222 CvpressStem with 3.000 Kings, 163: of 3,000 years, 163. Damp Wall Application, 85 ; Causes of, 85; Clay and Whiting for, 86; Lime and Portland Cement, 86. Dead Oil, 146; Absorbs Oxygen, 146; Coagulates Albumen, 146; Complete Protection, 148; C'on- tains Carbolic Acid, 147; Protects against Damp and Wet, 146; Pro- tects from Cremacausis, 146 ; Protects from Parasites. 140; Poisonous to Animal and Vege- table Life, 146; Shuts out Air and Moisture, 146. Decrease in Weight of Ash and Oak, 148 Dentists use Silica fts Plaster Moulds 52 Dentritic Forms, 31 Dentrition at Falls of Niagara, 258 Deposits of Salt, 313 ; How Obtuined, 318; Its Usep, 313. Descrii)tion of Green Sand, 818; of Quartz, 316; of Sand, 816; of • Sand Stone, 315. Different Kinds of Polypiferous Zoophytes, 2S0 Disappointment and Duff's Groupes Visit each other, 280 Discoverj'of Berzelins, 21 Disintegration, 38; ot Granite, 256; of Stone, 55. Dissolved Quartz, 34; The Gey- sers, 34. Distillation, Process of, 173 Distincticn of Animals and Plants, 261 Division of Rocky Masses, 305 Doebereiner's Composition, 15 Dolomite and Silicate, 90; Compo- sition. 90; Forms Extraordinary Hard Stone, 71. Double Soluble Glass, 44 Drain and Gas Pipe Cement, 225 Dr. KricL' 175 Dr. Loew's Remarks, 264 Dr. Liebig's Remarks, 265 Dr. Stevens' Classification of Rocks, 308 Dr. T. Sterry Hunt's Remarks, 268 Drusy Quartz, 26 Drying of Timber, 170 ; by Steana, 148 Dry W^ all Cement, 76 Dunging Salt 15 Dust, Volcanic 99 Earth, Calcination of, 43; History of, 275; Infusorial, 20: Must have had a Beginning. 275. Easel Painting, Stereo-Chromic, .. 137 Effloresence of Alkali, 44 Egyptian Jasper, 33 Emery Cement, ... 183 Eminently livdraulic Lime, 64 Enamel, Barvta, 133; Oxide of Chrome, 133; I'ltramarine, 133. Enamelling Culin.ary Vessels, 222 Essay on Carbonic Acids, 236; on Lime Stones, 273. Evaporation to Consistency, 42 Evidence of the Beginning or End of the Globe 276 Examination after One Year's Ex- posure, 136 Experiments of Ilansome, 17; of Rumford, 169 ; with Square Blocks, 141 Explanation of the True Artificial Stone, 123 Exjjosure for Ten Days, 44 ; to Pres- sure, 20, 57. Extraction of Soluble Salts, 55 Farm Houses 149 Felspar, 37, 92; Lime, 39; Mica, 39 ; Soda, 39 ; Potash, 39. Ferruginous Quartz, 27 Fibrous Quartz, 26 Fire Brick, 223; Cement, 53. Fire Cement, 77 Fire Opal 36 Fire Proof Cement, 223; Paint, 62, Fiske Concrete . 200 Flint, 31 ; Calcinntion of, 88; Glass, 18; in Chalk, 20; ol Chalk, 32; Marble, 87. 352 INDEX. Floors of Concrete, 216 Florida Keys, 280 Florite, 36 Fluohydric Acid for Hardening, ... 40 Fluorcalcium and t>oluble Glass, . . . 132 Fluoride Calcium, a Fusible Silicate, 40 Fluosilieate of Lime, 131 Fl or spar, 40 Formation of Opal, 119; of Quartz, 119; of Saltpetre, 119. Formations, Ape of, 308; Under the Surface of the Sea, from De- positions or Chemical Precipita- tion, 278 Foundation and Upper Pan 195 Foundation Wall Cement, 244 Fracture Quartz, 24 Frame Houses, Protection of, 210 Freestone, 317 Frequent KenewalsExi)ensive, 194 Fresco Painting, 117; Its Silicifica- tion, 117; Substitute, 127. Fringing or Barrier Coral Eeefs,. . . 285 Fringe Eeefs from Atolls, 285 Frog Grass, 19 Fungi Require Oxygen for Genera- tion 166 Furnace, Rcverberatory, 41 Fusing Quartz, 22 Gas, Carbonic Acid, 140; Oxygen, 140 Gems, Artificial, 341 German Hydraulic Cement, 94 Geodes Quartz, 34 Glass, 328; Bohemian, 13; Bottle, 13; Cement, 78; Character of, 336; Classification of, 331, 333; Constituents of, 329; Crystal, 13; Double Soluble, 44; Flint, 13; Frog, 19; History of, 328; Manufacture of, 335; Metal Ce- ment, 222 ; iSlot Scratched by Steel. 44; Physical Character of, S34 ; Soluble, 13, 39, 141 ; Stross, 13 ; Varieties of, 339 ; Water, 13; Window, 13. Glauber Salts 40, 138 Globe, Solid Surface of, 21 Glue, a Substitute for, 221 Granite, ! >isintegration of. 256 Granite, Gneiss, Micaschist and Compact Limestone 304 Granite Pavements, 198; Become Polished and Slipperj', 199 Granitic Sand, 37 Granular Quartz 33 Grape Vines, Soluble Glass as Manure for 919 Gravel, 37 Great Colorado Gors'e, 2'"0 Green Sand, 105, 816; Composition, 105 Green Vitriol, impregnated with Silica, 127 Grotto del Cane, 253 Gvpsum <\'ment. 225; Silicification of, 114 ; and Lime, 115. Hameliu's Cement 78 Hamilton's Cement 105 Hard Adhesive < ement, 225 Hard Cement, 133; Mortar Formed, 137 Hatdening of Chalk, 17; of Lime Similar to Gypsum, 122 Hardening Process, 92 Hardness of Ancient Mortar, 95; of Quartz, 24. Hard Limestone, 62 Haytorite, 33 Heart Wood Resists Kot, 146 Heliotrope, 29 Herb Kali, 19 Herkimer Quartz, 24 Heulandite, 39 History of Glass, 328; of the Earth, 275 Hornstone, 32; Calcination of, 38. Horses, Loss of, 193 Hot Springs of Arkansas, 292 Houses of Parliament, 18 House Timber. 51 How to Coat Wood, 141 Ilyahte, 38 Hydrated Silico Carbonate, 114 Hydrate of Lime, Reaction of, 68 Hydration of Aluminates of Lime, G7, 68 Hydraulic Cement, Artificial, 94 ; Composition, 94; German, 94. Hydraulic Lime, 58, 64; Infei-iority, 102: Meaning of, 65; Mortar, 58, 90; Where Found, 91. Hydraulic Limestone, American Mortar 90 Hydraulic Pre' sure, 48 Hydraulicity of Magnesia, 69 Hydiocarbons Solid at 400 to 500 deg. F., 174 Hydrochlorate Amnionia, 130 Hydrofluoric Acid, 131, 208; Appli- cations, 208; Forms an Insolu- ble Compound, 131 ; Mixed with Gypsum, 132; Price of, 57. Hydrogenium, 238 Hydrophane, 35 Hydrous Silicates, 39 Imitation Sandstone, 57 Impermeable " 224 Impregnation of Wood by Pres- sure. 156 ; by Preservative Liquids, 157. Increase in Weight, 144 Indeetructible Ink, 133 Indurating Action, 54 Inferiority of Hydraulic Lime, . . 102 Infusorial Earth, 20; Instead of Sand, 43. Infusoria of Planitz, 20 Injection of Silicates 118 Ink, Braconnot's, 133; Cochineal, 133; Indestructible, 133. Insoluble Precij)itate of Silica 144 Iron Block Pavement, 199 ; Fails in New York, 199; Its Advantages, 200; Succeeds in Boston, 199, Iron Cement, 77, 22fl Iron, Chloride of, 48 INDEX. 353 Iron and Stone Cement, 77 Iron, Oxide of, 138; Pyrolignite of, 145 Iron Ship Bottoms, Preservatives of, 212 Iron Test, 38 Itacolumite, 33 Jasper, 29; Agate, 31; Porcelain, 33 ; Egyptian, 33. Jelly, Colored, 43; Liquid, 16 ; Silica, 20 Juice in Vascular Tissue, 164 Kali Herb, 19; Vitrifying, 19, Kaulbach's Soluble (Jlass, 44 Keene's Cement 66 Kelp 19 Kreosotc Carbolic Acid, 143 Krieg'& Recommendation in 1858,, 143 Knhlman 16 Kuhlmaii's Cement, 78 ; Theoretical View, 112. Kunkcl 19 Kyan's Process, 145 Laths, Protection of, 210 Launionitc, 122 Lavoisier on the Cause of Harden- ing, 98 Left- Handed Crystal Quartz, 25 Liebig, 16 ; Process of, 20, Light Oil, 173 Lime, Ancient L,iw for, 90; Animal Product, 274; Chloride of, 140; Combination with Phosphoric Acid, 276; Derived from Disin- tegrated Kocks, 274; Eminently Hydraulic, 64; Felspar, 39; Fhio- siiicated, 131 ; Hydraulic, 68,64; Made through the Agency of Life, Animal or Vegetable,'276 ; Medium of Organic Beings in the Inorganic Process, 276; Mode- ratelv Hydraulic, 64 ; Plastic, 112;"Poor, 64; Rich, 61,64; Se- creted by Testacia and Corals, 274; Speculation on the Origin of, 277; Silicate, 15, 18; Test, 38; Water, 100; Weight of, 74. Limestone, 273; Argillaceous, 68; Hard, 63; Magnesian, 18, 52; of New York Island, 301; Described by Cozzens, 302 ; Silicifica- tion of, 131. Limped Quartz, 26 Lining for Barrels, 52 Linseed Oil Barrels, Protection of, 210 Liquid Jelly, 16 Lithograj)hic Stones, 187 Locust and Cedar Resist Decom- position, 154 Long Leafed and Northern Pine,.. 167 Loss of Horses, 193 Lubrkator, Cheapest, 212 Ludus Helmontii, 75 Lustre of Quartz, 24 Lute's Cement, 77 Lydian Stone, 32 Lye, Caiistic, 20; Preparation of,.. 43 Lyeirs Arguments, 278; Subdivi- sion of Kocks, 308. Mac Adam's Pavement, 1 80 ; System in 1816, 184. Magnesia, Hydraulicity of, 69; in Mortar, 93. Magnesian Limestone, 18, 52 ; of Potsdam Period, 293, Magnesium, Oxychloride of, 51, 108 Malt House Cement, 214 Mamillary Quartz, 24 Manganese Cement, 133 ; Peroxide, 126 Marble Cracks and Crevices, 52; Flint, 87. Marly Sandstone, 37 Martin's Cement, 66 Manufacture of Glass, 335 Materials for Building, 49; Formed into Rocks, 269, McGoncgal Pavement, 202 Meaning of Hydraulic Lime, 64; of Cement, 73, Menilite, 36 Merits of Wooden Pavements, 1S8 Mesotvpe, 122 MetalCement, 222 Metalic " 224 Method of Preserving Wood, 155; By Cold and Tepid Water, 155; Withdrawing the Albu- men, 155. Method of Vicat, 103 Mica Composition, 39 ; Felspar, 39, Micaceous Sandstone, 37 Microscopical Parasites, 162 Milky Quartz, 27 Millstones, 49 Mississip])i River Sand 37 Mixture, Vicat's, 103 Mocha Stone 31 Mode of Application, 207 Moderatel}' Hydraulic Lime, 64 Monuments, 49; Restored, 123. Mortar between Bricks, 62: Hy- draulic, 38, 90 ; Magnesia in, 93; Receipts, 80: Roman, 96; Rough, 128: Silica in, 93. Moss Agate, 29 Most Adhesive Insoluble Cement, . 212 Most Refractory Cement, 227 Mucilage, A Substitute for, 22l Munich Theatre, 16, 129, 141 ; Solu- ble Glass used in, 129. Mushroom Attacks Wood, 166 Natural Silicates, 119, 122: Apophvl- lite, 122; Effloresence, 122; Lau- monite, 122; Mesotype, 122; Stilbite, 122. Nature of Lime Determined, 63 Nature of Traffic, 195 Navy Tard, Brooklyn, 15, 141 Neri's Treatise 19 New Castle Coal contains 2>^ per cent, Phenic Acid, 174 New Jersey River Sand, 3*? Niagara Falls Detrition, 258 Nicolson Pavement, 201 Nineteenth Century, 5S 354 INDEX. Nitrate Soda, 40, 121; Where De- rived, 121 ; Where Found, 121. Non-Intiammable Wood, 51 NuUipores, Calcareous Vegetation, 284 Nullipores Look Like Plants, 2S8 Oak and Ash Decrease in Weight,. 148 Objections to Stone and Wood Pavements, 188 Oertlyand Fendrich, 107; Coating, 107; Iron Stone, lUS; Kadiating Power. 110; Eemarks, 110. Oil, Brownish, 173; Light, 173. Oleaginous Va])or Process, 172 Onyx 31 Opal, 35: Agate, 36; Common, 35; Fire, 35 : Formation, 119 ; Green, 35; (h-ange, 35; Kesin,85; Solu- ble in Potash, 37; Wood, 36. Orange Opal 35 Ordnance Department, 15 Origin of Alkalies, 309; Calcareous Deposits, 291 ; Chalk, 296 ; Lime, 277 Oxide, Burnt, 138 ; Chrome, 126 ; Chrome P^namel, 133 ; iron, 138 ; Eaw, 138. Oxychloride of Magnesium, 51, 103 Oxygen Compounds, 38 ; Gas, 140. Pacific, 290 ; Coral Islands in the, 282 Paint, An ti -Rust, 53 ; Baryta, 133 ; Fire-Proof, 52. Painting, Exposed for One Year, 128: Fresco, 117; Silica, 132: Silicate, 117 ; Precaution in, 135 ; Upper Ground for, 137 ; with Brush, 208. Parian Cement, 66 Parisian Pavement, 179 Patents of Bobbins and Moll, 175 Pavement, Asphalt, 1T9 ; Broadway, 196; Brown and Miller, 204; Granite, 198 ; Granite becomes Polished and Slipperj^ 199 ; Iron Block, 199 ; Iron Blocks Fail in New York and Succeed in Bos- ton, 199 ; McGonegal. 202 ; Nicol- son, 201 ; Bobbins, 204; Seeley's (Concrete, 205: Stafford, 204; Stowe, 203; The Coming, 205; Typical Historical, 191. Payen Recommends Caustic Alkali, 154 Pearlash, Purifying of, 39 Peasley Cement, 116 Percentage of Clay, 102 Perchloric Acid, 131 Permanent White, 138 Phenic Acid, 173 ; Cannel Coal Tar Contains 7 per ct., Newcastle 2)4 per ct., Staffordshire 4>^ per ct., Average 5 per ct., 174 Phenocrystalline Quartz, 25 Phenomena of Good Lime, 63 Phosphoric Acid, 138 Physical Character of Glass, 334 Pitch of Dead Oil, 146 Planitz, Infusoria, 20 Planks and Blocks, How to Prepare, 206 Plasma, 29 Plaster Cement, 66 ; Paris, 66. Plastic Lime, 112 Pliny and Vitruvius, 97 Pliny's Ideas on Wood Decay, 166 : Statement, 19. Polarization of Quartz, 24 Poles, Telegraph, 51 Polveriue, 19 Polypifurous Zoojihytes 280 Pontine Marshes, 74 Poor Lime, . . 64 Porcelain Jasper, 33 Portland Cement, 05 : Analysis, 73 ; Where Manufactured, 104. Potash Felspar, 39 ; Silicate, 13 : Soluble Glass, 41 ; Soluble Glass Whitewash, 44 ; Water Glass, 18. Potassium, 21 ; Character of, 310 ; Compounds, 311 ; Fluoride, 21 ; Siliciuret, 21, Prase, 29 Precaution in Painting, 135 Precipitated by Alcohol, 42 Preparation of Planks and Blocks,. 206 Preparing Underground, 130 Preservation by Champty (Dipping in Suet), 152 , by De Saussure, 152, by Fagol (1T40), bv Haller (1756j, bv Jackson (1767), by Kyau (1830), by Pallas (1779), 151 ; by I'ayeu {Dipping in liosin), 152 ; by Immersion, 150 ; of Walls, 209 ; with Alum and Sulphate of Iron, 151. Preservatives of Iron Ship Bottoms, 212 Price of Hydrofluoric Acid, 57 Process 01 "Distillation, 173 Process of LiebiK, 20 ; of Violitter, 148 Prof. Henry's Statement of Niagara Falls, 259 Prosser's System, 162 Protection against Combustion, 146 : of Alcohol Barrels, Cisterns, Cross Ties, Frame Houses, Lath, Linseed Oil Barrels, Rail Road Sleepers, Staves. Shingles, Spirits Turpentine Barrels, Telegraph Poles. Timber, 210 Prismatic Face Quartz, 24 Pseudomorphous " 83 Pumice, Volcanic, 99 Pure Silica, 38 Purifying Pearlash, 39 ; Soda-ash, 39 Puzzuolana, 61 Puzzuolanic Action, 67 ; Silicates,.. 69 Pyrolignite of Iron, 145 Quantity of Carbonic Acid Pro- duced, 251 Quartz, Amethystine, 26 ; Aven- turine, 27 ; Babel, 34 ; Calcination of, 38 ; Cap, 26 ; Cat's Eye, 27 ; Cavernous. 26 ; Chalcedony, 28 ; Characteristic Features of, 323 ; Cleavage, 23; Colors, 24; Con- nectionary, 24 ; Conglomerate, INDEX. 355 33 ; Constituents of, 22, 25 : Cryp- to-Crystalline, 25 ; Crystal Form, 23; Description of, 316; Dis- solved, 34 ; Drnsy, 26 ; Ferrugin- ous, 27 ; Fibrous, 26 ; Formation, 119; Fracture, 24; from Herki- mer, 24 ; from Ulster, 24 ; Fusing-, 22 ; Geodes, 34 ; Granular, 33 ; Hardness, 24 ; Left-IIanded Crys- tals, 25 ; Limped, 25 : Lustre, 24 ; Mamillary Form, 24 ; Milky, 27 ; Phenocrystalline, 25 ; Polariza- tion, 24 ; Prismatic Faces, 24 ; Pseudomorphous, 33 ; Radiated, 26 ; Kight-Hauded Crystals, 25 ; Kose, 26 ; Sageiiite, 27 ; Sapphire, 27 ; Siderite, 27.; Size of Crys- tals, 24 ; Smoky, 27 ; Soluble in Fluohydric Acid, 25 ; Specific Gravity, 24 : Stalactitic, 24 ; Star, 26 ; Streak, 24 ; Swinuning, 36 ; Symbol, 25; Tabular, 33; Varie- ties of, 326 ; Vitreous Varieties, 25 Quartzose Sandstone, 33 Quicklime Lighter than Lime, 63 Radiated (iuaitz, 26 Rail Road Sleepers, 51 ; Protection of, 210 ; Secured, 142. Rails of Ik'achWood, 160 ; of Scotch Fir, ir.9, Raudanite, 36 Ransome's Artificial Stone, 54 Ransome's Experiment, 17 Raw Oxide 13S Reaction of Hydrate of Lime, 68 Reduction to Granular Condition,. 38 Reef Building Coral, 286; 120 Spe- cies, 286, Reese's Cement, 78, 105 Relative Claims of Wood nnd Metal as Material for Rails 157 Remarks of Dr. Liebig, 265 ; of Dr. Lowe, 264 ; of T. Sterry Hunt, . . 268 Report on Wooden Railways, 158 Resin Opal, , 35 Reverberatory Furnace, 41 Rich Lime 61. 64 Richmond, Va., Stratum, 20 Right-Handed Crystal Quartz, .... 25 River Be his, 19 River Sand from Mississippi, 37 ; from New Jersej', 87. Robbins and Moll's Patent, 175 Robbins' Patent, 172; Pavement,. 205 Rochetta, 19 Rock Crystal, 824 Rocks, Arrangement of, 305 ; Divi- sion in Ages, 305 ; Sedimentary, 304 ; Sub-Division of Geological Time, 307 ; Sub-Division of Lyell, 888 Rocky Masses Divided 305 Roman Cement, 65, 104; Where Manufactured, 104. Roman Mortar, 96 Rondout Hydraulic Lime, Analysis of, 75. Roofing Cement, 53 Rose Quartz, 26 Rosin, 145 Rough Mortar, 128 Royal Theatre, Munich 16 liumford's Experiments, 169 S.agenite Quartz, ; 27 Salt, 140 ; Dunging, 15 ; Deposits, 313; How Obtained. 313; Its Uses, 313 : Glauber, 40, 138. Salts of Strassford, 812 Saltpetre Formation, 119 ; from Mammoth Cave, 121 ; Missouri, 121 ; Tennessee, 121. Sand, 316 ; Alluvial, 37 ; Angular Grains, 37 ; Ancient Law for, 98 ; Calcination of, 48: Digested in Chlorohydric Acid, 38 : Granitic, 37; Green, 105, 817; Vol- canic, 37. Sandstone, 315 ; Argillaceous, 37 ; Common, 87; Flexible, 33, 37; Imi- tation, 57 : Murly, 37 : Micaceous, 37 ; Quartzose, 33 ; Silicification of, 124 ; Volcanic, 37, Sap, Aualvsis.of, 164 Sapi)hire ^iuartz 27 Sardonyx, 31 Sea Water, Utilization of, 312 Secret of the Venetian Fiddle Makers, 14'J Sedimentary Rocks, 804 Beeley's Pavement, 178, 205 ; Fail- ure on Fifth Avenue, 205 Separati ni Oty XV til fine. ^^ fire. " 35 14th " " acidity, allvali, silification, silicification, " 58, 13th " " linicular. u lenticular, 75, 2d " " sillification, u silicification, " 113, 6th " " do. u do. " 113, 16th " " do. do. " 114, 11th " " do. u do. " 131, 10th " " appled. u applied. " 133, 2d " " sillification. u silicification. " 140, at the head, an the whole chaptei colito. oolite. " 283, 2d line. sihivian. Silurian, " 300. is. a are, " 297. ooletic. ii oolitic. " 295. group. u gravity. " 289. 150,000,000, read 150,000, " 309 GETTY RESEARCH INSTITUTE 3 3125 01000 9195