Volume 24 (1872) (424 pages)

January 20, 1872. ] SCIENTIFIC PRESS: 35 IM ECHANICAL ‘PRoGRess Machine Puddling a Success. No improvement in modern days has been more earnestly desired by the iron trade thau a successful, practical machine puddler. The attainment of such an invention can not be considered of any lvss value thau the Bessemer process of making stecl. Varions devices have been tried with greater or less snecess, the most promising of which have been based upon the principle of employing a rotary chamber iu which to perform the work. Sueh devices have been tried both in this couutry and iu Europe, and have besn found perfectly practical with ths single cxception of the difficulty attending the procurement of a durable lining for the chamber. During the past year, snecess in this important particular has been claimed hy a Mr. Danks, of Cincinnati, who las devised a lining which issaid to fully meet all reasonable requiremeuts. Mr. after putting suelis furnace into succcssful operation in Cincinnati, went to England, of which country ho is a native, and explained his process in an elaborate papsr, read before the Iron and Steel Institute. His deportment was such as to securo the confidence of that association to such an extent that it appointed a committee of experts to return with bim and thoroughly examine into ths merits of the alleged invention. This commission left England early in October last, taking with them abont 40 tons of different kinds of English pig-irons, (such as they had unsuccessfully experimsnted with,) to be operated on as a crucial test. This commission has telegraphed to England, as stated in onr issue of last week, that they had fonnd the invention a complste success, a resnlt which will at once insure its general adoption in Eugland and on the Continent. The Dank's Furnace, Aside from its obvious general mechanical arrangement and construction,consists of rotating upon a horizontal axle ono end ofa chamberwhich communicates with afnrnace in which the flamsis urged hy fan-blasts, and the other with a flue; this latter heing closed by a detachahle head while the apparatus is in use. Tho rotation of the chamber, duly charged with molten pig, of courss insures the requisite movement of the metal, and consequently the results commonly obtained hy the action of the puddlsr’s tool. At the proper stage of the process, tbe head of the chamber is taksn . off, the flue moved asido out of the way, and a large fork suspended from a eraneis thrnstin. A few turns of the chamber then causes the ball to adhero to the fork, and the latter hsing withdrawn conveys tbe ball to the squeezing machinery. The method of lining this chamber is described as follows: “The foundatiou for the lining consists of a mixture of pulverized iron ore and pure lime, worked with water into the consistency of a thick paste. Upon the complstion of the initial lining, a quantiof pnlverized iron ore, about one-tifth of the total amount required to lino the apparatus, ia tbrown in, tbe furuancs is heated and mado to revolve slowly until the iron is fonnd to be completely melted, when the apparatns is stopped. That part of tbe molten iron which has not been consumed by glaziug the initial lining surface runs to the lowest level of the furnaco, and there forms a pool, into which thsre are puta number of small and largo lumps of irou ore ofsuch dimensionsas will bs reqnired toallow the said lumps to project over the surface of the liquid ore by from two to six inches, This part of the lining is allowed to set, when afresh quautity of pulverized ore is thrown in. The furnace is again mado to rotate slightly until the newly added ore is liqneticd, whsn the apparatus is again stopped, and the pool fillsd with lumps as hefore. The operation is continued iuthis way until the whole of the vessel is properly liued. From 2 to 2% tons of iron ore are required to line a 700 Ibs. furnace. The London Mining Journal in alluding tothe reported success of this invention, says: ‘‘Tho news appears too good to he true. The problem will, howover, soon have its solution. We shall then know if in the United States there is at work a rotary puddling furnace which, although not very diffsrsnt from that with which Mr. Menelaus has been experimenting, yet has distinguished itself with important difference of having heen a succsss, while the British machine cannot be so regarded.” Our cotemporary has ere this found the “news” beth “good” and ‘‘truc,” and ths meeting of the Iron and Stecl Association before whom Mr. Danks read his paper, already referred to, will become, as the Journal said it would, if the expectations thus raised were realized, ‘‘more msmorable in the history of ths iron trade than that meeting in Cheltenham, at which Mr. Bessemer read to the British Association his famous paper, will prove to the steel trade.” It thus appears that this American invention is destinsd to take its place foremost among the improvemeuts adopted by the greatest iron-making country in the world. The real value of ths priuciple is shown not only in the doing away of ths severe manual labor in ths puddling operatiou, but also in theproductiouof larger ballsat a single heat than could be done by the old msthod; in an iucreased economy of fuel, and a greater yield of iron from a given grade and quautity of ore. In the furnaess at Cincinuati, puddled balls ranging from 650 to 1,000 pounds are convenisntly made, and no special difficulty appears to have been met with in forming iuto a siugle ball the product of a heat of 1,400 pounds. Theironischarged iuto tho furnace eithsr in a solid or molten coudition. Whsn charged in the shape of pig-iren, the melting down oceupies from 30 to 35 minutes, during which a partial rotation is given to the furnace from time to time in order to expose equally all sides of the charge to the flame. When the whole of this is thoroughly melted, the furnace is made to rotateonly onceortwicepsr minute during the five or tsu minutes, in order to obtain the most perfect action of the cinder upon the molten iron. But this article has already hecome quite too long to admit of any further details of the process at this time. Ponverzzep Furr—A Serriove DrawBAOK.—An ‘‘eminent engineer,” who has had some expsrience in the use of pulverized fuel, says that although perfectly successful at first, it grew gra@ually unsatisfactory from the glazing produced upon the flues, grates, etc.; the percentage of silex, etc., wbich in ordinary stoking and burning is carried off as slag and refuse, heing carried against the throat, etc., hrings on a vitreous diptheria which is fatal to tho flues. It is intimated in reply that in the use of this kind of fnel, much will of course depend upon tbe character of the material. If the refuse is easily vitrified, then the result described may possibly occur; but, if the refuse is not easily vitrified, it will he carried out of the chimney in the form of dust. Pulverized fuel has heen successfully used by several establishments for a year or more, and is no doubt the most economical way in which coal can be used, when the ohjection above referred to does not interpose. By reference to anotber column it will he sesn tbat the principle is ahout to be introduced into one of the principal machine shops in this city. InPROvVED CoNSTRUCTION OF SHEET-IRON Sraces.—Shest-iron stacks, especially for heating and puddling furnaces, are now being made in ssparate rings, instead of one whole Isngth as formerly. Eacb ring has a hand of flat har-iron—horseshoe har —ahout two inches from the lower edge, firmly riveted, and by which each is supported as it fitsinto and rests on the edge of the one next below. By making the stack in this way in short ssctions, it can be more conveniently erected, and also can be repaired by renewing any worn-out part or burnt section at less cost and much Isss lahor than when otherwise constructed. SPrep oF OcEsn STEAMERs.—The steamship Oceanic, of the new “ White Star” line, during a late trip from New York to Liverpool, ran 384 knotsin a single day, which is spoken of hy soms of the newspapers as heing the greatest distance ever made in twenty-four hours. This, says the American Artizan, seems to be a mistake, for we find hy referenco to our records of the passages of steamers, that the City of Baltimore, of the ‘‘Inman” line, ran 385 miles in twenty-four hours, in the year 1866. Tron SHie-BUILDING IN THE UNITED Srates.—No iron sbips were built in the United Statss in 1867. In 1868 six small vessels wsre constructed, having an aggrsgato of 2,800 tons; in 1869 ten were built, of an aggregato of 4,58£ tons; in 1870 fifteen, with an aggregate hurthen of 8,281 tons; and in 1871, up to ths middle of No vemhsr, twenty were constructed, measuring an aggregate of 15,479 tons. Of the twenty iron vessels built during the year ending January 31, 1871, nineteen were steamers, §cientiric Proaress. The Force of Life. Thers have been writers who aflirmed that the pyramids of Egypt were the produetions of Nature. We now regard them as the work of men’s lands, aided hy machinery of which uo record remains. Tho blocks iu this case were moved bya power external to themselves, and the tinal form of the pyramid expressed the thought of the human builder. Let us pass from this illnstration of building powsr to another of a differsnt kind. When a solution of commen salt is slowly evaporated ths water disappears, but the salt remains behind. At csrtaiu stages of concentration particles, or melscules, as they are called, begin to deposit themsefves as minutesolids, so minute, indesd, as to dsfy all microscopie power. As evaporation continues, solidifications goss on and we finally obtain a mass of sult of adefinte form. What is this form? It sometimes seems as a inimicry of the architecture ef Egypt. We havs little pyramids, tsrrace abovs terace forming a seriss of stepe resembling thoss of ths pyramids. Ths human mind is as little disposed to look at these littls salt crystals without further question as to look at the pyramids of Egypt without inquiring whence they came. How, then, are those salt pyramids built up? Guided by aualogy, we may supposs that swarming among the constituent molecules of the salt there is an invisihle population, guided and coerced by some invisible master, and placing the atomic blocks in their positions. This, however, is not tho scientitic idea, nor do I think your good sense will accept it asalikely one. The scieutific idea is that the molocules act upon each other without the intervention of slave labor; that they attract and repel each other at definite points, and in certain differeut directions, and that the pyramidal form is the result of this play of attraction and repnision. While then the blocks of Egypt were laid down hy a powsr external to themselves, these molecular blocks of salt are self posited, being fixed in their places hy the forces with which they act upon eacb other. I tako common salt as an illustration, because it ie so familiar but almost any other suhstance would answer equally well. In fact, throughout organic Nature, we have this structural energy ready to come into play. It ispresent everywhere. The ice of our winters and of onr polar regions is its hand-work, and so equally are the quartz, feldspar and of mica of our rocks. This tendency of matter to organize itself, to grow into shape, to assume dsfinite forms in obedience to the definite action of force, is all-pervading. It isin the ground on which you tread, in the water you drink, in tbe air you hreath. Incipient life, infact, manifests itself throughout the whole of what we call inorganic Natnre. ‘ The forms of minerals resulting from this play of forces are various and exhibit different degress of complexity. Men of science avail tbemselves of all possible means of exploring this molscular architecture. For this purpose they employ as agents of exploration, Jigbt, heat, maguetism, electricityandsound. Polarized light is especially useful and powerfulhsre. A beam of such light, when sent into the molecules of a crystal, is acted on hy them and from this action we iufer with more or lsss clearness the manner in which the molscules are arrangod. The diffsrence, for example hetween the inner structure of a plate of rock-salt anda plate of erystallized sugar isthus strikingly revealed. And now let us pass from what we. are accustomed to regard as a dead minsral, to a living grain of corn. When it is examined hy polarized light, chromatic phenomena similar to those noticed in erystals are ohserved. And why? Because the architecture of the grain resembles in some degree the architecture of the crystal. Inthe corn the molecules are alsa sst in definite positions, from which thsy act upon the light. But what has huilt together the molecules of the corn! I have already said, regarding crystalliue architscture, that you may, if you pleass, consider the atoms and molecules to hs placed in position hy a power external to themselves. The same hypothesis is open toyou now. But,if in the case of crystals you have rejected this notion of an external arebitect, [think you are bound to reject it now, and to conclude that the molscules of corn are self-posited by the forces by which they act upon cach other. It would be peor philosophy to invoke an external agent in the one cass, and reject it in ths other. But, I must go still further, and affirm that in the eye of scisnes the animal body is just as much the product of molecular fores as the stalk and ear of corn, or as ths erystal of salt or sngar. Many of its parts are obviously mechanical. Take the hnman heart, for example, with its exquisite system of valves, or take the eye or haud. Animal leat, moreover, isthe same in kind as ths heat of a firs, being produced by ths sams chemical process, Animal motion, too, is dirsctly derived from ths feed of tho auimal. As regards matter, the animal body creates nothing; as regards fores, it creates nothing. Which of you by taking thought ean add ons cubit to his staturs? All that las been said regarding ths plant may bs re-stated with regard to the animal. Every particle that entsrs into the composition of a musels, a nerve, or a boue, has been placed in its position by a molscular force ; and unless the existence of law in thess matters bs denied, and the element of caprice be introducsd, we must concluds that, given the relation of any moleculs of ths bedy to its environment, its position in the body might hs prsdicted. Our difficulty is not with the quality of the preblem, but with its complexity ; and this difficulty might be mst by the simple expansion of the faculties which man now possesses. Given this expansion, and given the necessary molecular data, the chick might he deduced as rigorously and as logically from the egg as the existence of Neptune was deduced fromjthe disturhances of Uranus, or as conical refraction was deduced from the undulatory theory of light.—Condensed from a lecture by Tyndall. Iron Electrotypes. The art of elsctrotyping, says a contemporary, already applied to myriad uses, shows constant evidsnce of progress, especially in tbe successful dsposition for practical purposes of metals that havs hitherto heen considered intractahle. Nickel-plating is uow common, and, while cheaper, is for soms purposes suporior to silver; and there is some reasou to snppose that by the employment of a smail psreentage of some other metal to diminish the brittleness, the rather refractory nature of the nickel coating may be hrought more completely under the control of the hurnisher, in lieu of the polisbing whesl, than is now the case. There are many purposes, however, for whick a plating of iron would be, all things considered, bstter than any of those now familiar in elsctro-metallurgy; and to secure this has occupied tho attention of some foreign experimenters, who have, apparently, been very succossful in thsir efforts. At the late London International Exhibition (1871) were exhibited bank-note plates, medallions, and a page of printingtype, elsctrotyped in iron, by a process devised by M. Engene Klein, who is at the head of the Chemical Department in the Imperial State Paper Manufactory in St. Petersburg. The advancement of the iron electrotype to a practical success has not heen accomplished witbout the expenditure of much thought and experiment, and many difficulties haye had to be surmounted; but the scisntific interest which attachsd to the new development, and the eminently useful applications of which he saw it was susesptible, especially in the departments of engraving and printing, stimulated M. Klein to continus his experiments, against what appeared to hs almost or quite insurmountahle hindrances. His starting point was the steeling of sngraved copper-plates, which process was effected in a bath composed of chlorate of ammonia and iron, to which he added a small quantity of glycerine. On leaving the bath the iron is as hard as tempered steel and very hrittls. Reheated it loses much of its hardness, and hscomes mallsable at cherry red, when it may be cut with the graver as readily as soft steel. Of the importance of the practical application of the process there can he no douht whatever. By replacing plates of copper by those of iron, greater facilities will he afforded for producing publications, works of art, and especially hank-notes and checks. Iron electrotype plates are found to be almost indestructihle in the process of printing, while copper soon wears out— much sooner, in fact, than wood. A late issue of Engineering gives in detail the expsrimonts through which this important process has advanced toa condition of high practical value.

January 20, 1872. ] SCIENTIFIC PRESS: 35 IM ECHANICAL ‘PRoGRess Machine Puddling a Success. No improvement in modern days has been more earnestly desired by the iron trade thau a successful, practical machine puddler. The attainment of such an invention can not be considered of any lvss value thau the Bessemer process of making stecl. Varions devices have been tried with greater or less snecess, the most promising of which have been based upon the principle of employing a rotary chamber iu which to perform the work. Sueh devices have been tried both in this couutry and iu Europe, and have besn found perfectly practical with ths single cxception of the difficulty attending the procurement of a durable lining for the chamber. During the past year, snecess in this important particular has been claimed hy a Mr. Danks, of Cincinnati, who las devised a lining which issaid to fully meet all reasonable requiremeuts. Mr. after putting suelis furnace into succcssful operation in Cincinnati, went to England, of which country ho is a native, and explained his process in an elaborate papsr, read before the Iron and Steel Institute. His deportment was such as to securo the confidence of that association to such an extent that it appointed a committee of experts to return with bim and thoroughly examine into ths merits of the alleged invention. This commission left England early in October last, taking with them abont 40 tons of different kinds of English pig-irons, (such as they had unsuccessfully experimsnted with,) to be operated on as a crucial test. This commission has telegraphed to England, as stated in onr issue of last week, that they had fonnd the invention a complste success, a resnlt which will at once insure its general adoption in Eugland and on the Continent. The Dank's Furnace, Aside from its obvious general mechanical arrangement and construction,consists of rotating upon a horizontal axle ono end ofa chamberwhich communicates with afnrnace in which the flamsis urged hy fan-blasts, and the other with a flue; this latter heing closed by a detachahle head while the apparatus is in use. Tho rotation of the chamber, duly charged with molten pig, of courss insures the requisite movement of the metal, and consequently the results commonly obtained hy the action of the puddlsr’s tool. At the proper stage of the process, tbe head of the chamber is taksn . off, the flue moved asido out of the way, and a large fork suspended from a eraneis thrnstin. A few turns of the chamber then causes the ball to adhero to the fork, and the latter hsing withdrawn conveys tbe ball to the squeezing machinery. The method of lining this chamber is described as follows: “The foundatiou for the lining consists of a mixture of pulverized iron ore and pure lime, worked with water into the consistency of a thick paste. Upon the complstion of the initial lining, a quantiof pnlverized iron ore, about one-tifth of the total amount required to lino the apparatus, ia tbrown in, tbe furuancs is heated and mado to revolve slowly until the iron is fonnd to be completely melted, when the apparatns is stopped. That part of tbe molten iron which has not been consumed by glaziug the initial lining surface runs to the lowest level of the furnaco, and there forms a pool, into which thsre are puta number of small and largo lumps of irou ore ofsuch dimensionsas will bs reqnired toallow the said lumps to project over the surface of the liquid ore by from two to six inches, This part of the lining is allowed to set, when afresh quautity of pulverized ore is thrown in. The furnace is again mado to rotate slightly until the newly added ore is liqneticd, whsn the apparatus is again stopped, and the pool fillsd with lumps as hefore. The operation is continued iuthis way until the whole of the vessel is properly liued. From 2 to 2% tons of iron ore are required to line a 700 Ibs. furnace. The London Mining Journal in alluding tothe reported success of this invention, says: ‘‘Tho news appears too good to he true. The problem will, howover, soon have its solution. We shall then know if in the United States there is at work a rotary puddling furnace which, although not very diffsrsnt from that with which Mr. Menelaus has been experimenting, yet has distinguished itself with important difference of having heen a succsss, while the British machine cannot be so regarded.” Our cotemporary has ere this found the “news” beth “good” and ‘‘truc,” and ths meeting of the Iron and Stecl Association before whom Mr. Danks read his paper, already referred to, will become, as the Journal said it would, if the expectations thus raised were realized, ‘‘more msmorable in the history of ths iron trade than that meeting in Cheltenham, at which Mr. Bessemer read to the British Association his famous paper, will prove to the steel trade.” It thus appears that this American invention is destinsd to take its place foremost among the improvemeuts adopted by the greatest iron-making country in the world. The real value of ths priuciple is shown not only in the doing away of ths severe manual labor in ths puddling operatiou, but also in theproductiouof larger ballsat a single heat than could be done by the old msthod; in an iucreased economy of fuel, and a greater yield of iron from a given grade and quautity of ore. In the furnaess at Cincinuati, puddled balls ranging from 650 to 1,000 pounds are convenisntly made, and no special difficulty appears to have been met with in forming iuto a siugle ball the product of a heat of 1,400 pounds. Theironischarged iuto tho furnace eithsr in a solid or molten coudition. Whsn charged in the shape of pig-iren, the melting down oceupies from 30 to 35 minutes, during which a partial rotation is given to the furnace from time to time in order to expose equally all sides of the charge to the flame. When the whole of this is thoroughly melted, the furnace is made to rotateonly onceortwicepsr minute during the five or tsu minutes, in order to obtain the most perfect action of the cinder upon the molten iron. But this article has already hecome quite too long to admit of any further details of the process at this time. Ponverzzep Furr—A Serriove DrawBAOK.—An ‘‘eminent engineer,” who has had some expsrience in the use of pulverized fuel, says that although perfectly successful at first, it grew gra@ually unsatisfactory from the glazing produced upon the flues, grates, etc.; the percentage of silex, etc., wbich in ordinary stoking and burning is carried off as slag and refuse, heing carried against the throat, etc., hrings on a vitreous diptheria which is fatal to tho flues. It is intimated in reply that in the use of this kind of fnel, much will of course depend upon tbe character of the material. If the refuse is easily vitrified, then the result described may possibly occur; but, if the refuse is not easily vitrified, it will he carried out of the chimney in the form of dust. Pulverized fuel has heen successfully used by several establishments for a year or more, and is no doubt the most economical way in which coal can be used, when the ohjection above referred to does not interpose. By reference to anotber column it will he sesn tbat the principle is ahout to be introduced into one of the principal machine shops in this city. InPROvVED CoNSTRUCTION OF SHEET-IRON Sraces.—Shest-iron stacks, especially for heating and puddling furnaces, are now being made in ssparate rings, instead of one whole Isngth as formerly. Eacb ring has a hand of flat har-iron—horseshoe har —ahout two inches from the lower edge, firmly riveted, and by which each is supported as it fitsinto and rests on the edge of the one next below. By making the stack in this way in short ssctions, it can be more conveniently erected, and also can be repaired by renewing any worn-out part or burnt section at less cost and much Isss lahor than when otherwise constructed. SPrep oF OcEsn STEAMERs.—The steamship Oceanic, of the new “ White Star” line, during a late trip from New York to Liverpool, ran 384 knotsin a single day, which is spoken of hy soms of the newspapers as heing the greatest distance ever made in twenty-four hours. This, says the American Artizan, seems to be a mistake, for we find hy referenco to our records of the passages of steamers, that the City of Baltimore, of the ‘‘Inman” line, ran 385 miles in twenty-four hours, in the year 1866. Tron SHie-BUILDING IN THE UNITED Srates.—No iron sbips were built in the United Statss in 1867. In 1868 six small vessels wsre constructed, having an aggrsgato of 2,800 tons; in 1869 ten were built, of an aggregato of 4,58£ tons; in 1870 fifteen, with an aggregate hurthen of 8,281 tons; and in 1871, up to ths middle of No vemhsr, twenty were constructed, measuring an aggregate of 15,479 tons. Of the

twenty iron vessels built during the year ending January 31, 1871, nineteen were steamers, §cientiric Proaress. The Force of Life. Thers have been writers who aflirmed that the pyramids of Egypt were the produetions of Nature. We now regard them as the work of men’s lands, aided hy machinery of which uo record remains. Tho blocks iu this case were moved bya power external to themselves, and the tinal form of the pyramid expressed the thought of the human builder. Let us pass from this illnstration of building powsr to another of a differsnt kind. When a solution of commen salt is slowly evaporated ths water disappears, but the salt remains behind. At csrtaiu stages of concentration particles, or melscules, as they are called, begin to deposit themsefves as minutesolids, so minute, indesd, as to dsfy all microscopie power. As evaporation continues, solidifications goss on and we finally obtain a mass of sult of adefinte form. What is this form? It sometimes seems as a inimicry of the architecture ef Egypt. We havs little pyramids, tsrrace abovs terace forming a seriss of stepe resembling thoss of ths pyramids. Ths human mind is as little disposed to look at these littls salt crystals without further question as to look at the pyramids of Egypt without inquiring whence they came. How, then, are those salt pyramids built up? Guided by aualogy, we may supposs that swarming among the constituent molecules of the salt there is an invisihle population, guided and coerced by some invisible master, and placing the atomic blocks in their positions. This, however, is not tho scientitic idea, nor do I think your good sense will accept it asalikely one. The scieutific idea is that the molocules act upon each other without the intervention of slave labor; that they attract and repel each other at definite points, and in certain differeut directions, and that the pyramidal form is the result of this play of attraction and repnision. While then the blocks of Egypt were laid down hy a powsr external to themselves, these molecular blocks of salt are self posited, being fixed in their places hy the forces with which they act upon eacb other. I tako common salt as an illustration, because it ie so familiar but almost any other suhstance would answer equally well. In fact, throughout organic Nature, we have this structural energy ready to come into play. It ispresent everywhere. The ice of our winters and of onr polar regions is its hand-work, and so equally are the quartz, feldspar and of mica of our rocks. This tendency of matter to organize itself, to grow into shape, to assume dsfinite forms in obedience to the definite action of force, is all-pervading. It isin the ground on which you tread, in the water you drink, in tbe air you hreath. Incipient life, infact, manifests itself throughout the whole of what we call inorganic Natnre. ‘ The forms of minerals resulting from this play of forces are various and exhibit different degress of complexity. Men of science avail tbemselves of all possible means of exploring this molscular architecture. For this purpose they employ as agents of exploration, Jigbt, heat, maguetism, electricityandsound. Polarized light is especially useful and powerfulhsre. A beam of such light, when sent into the molecules of a crystal, is acted on hy them and from this action we iufer with more or lsss clearness the manner in which the molscules are arrangod. The diffsrence, for example hetween the inner structure of a plate of rock-salt anda plate of erystallized sugar isthus strikingly revealed. And now let us pass from what we. are accustomed to regard as a dead minsral, to a living grain of corn. When it is examined hy polarized light, chromatic phenomena similar to those noticed in erystals are ohserved. And why? Because the architecture of the grain resembles in some degree the architecture of the crystal. Inthe corn the molecules are alsa sst in definite positions, from which thsy act upon the light. But what has huilt together the molecules of the corn! I have already said, regarding crystalliue architscture, that you may, if you pleass, consider the atoms and molecules to hs placed in position hy a power external to themselves. The same hypothesis is open toyou now. But,if in the case of crystals you have rejected this notion of an external arebitect, [think you are bound to reject it now, and to conclude that the molscules of corn are self-posited by the forces by which they act upon cach other. It would be peor philosophy to invoke an external agent in the one cass, and reject it in ths other. But, I must go still further, and affirm that in the eye of scisnes the animal body is just as much the product of molecular fores as the stalk and ear of corn, or as ths erystal of salt or sngar. Many of its parts are obviously mechanical. Take the hnman heart, for example, with its exquisite system of valves, or take the eye or haud. Animal leat, moreover, isthe same in kind as ths heat of a firs, being produced by ths sams chemical process, Animal motion, too, is dirsctly derived from ths feed of tho auimal. As regards matter, the animal body creates nothing; as regards fores, it creates nothing. Which of you by taking thought ean add ons cubit to his staturs? All that las been said regarding ths plant may bs re-stated with regard to the animal. Every particle that entsrs into the composition of a musels, a nerve, or a boue, has been placed in its position by a molscular force ; and unless the existence of law in thess matters bs denied, and the element of caprice be introducsd, we must concluds that, given the relation of any moleculs of ths bedy to its environment, its position in the body might hs prsdicted. Our difficulty is not with the quality of the preblem, but with its complexity ; and this difficulty might be mst by the simple expansion of the faculties which man now possesses. Given this expansion, and given the necessary molecular data, the chick might he deduced as rigorously and as logically from the egg as the existence of Neptune was deduced fromjthe disturhances of Uranus, or as conical refraction was deduced from the undulatory theory of light.—Condensed from a lecture by Tyndall. Iron Electrotypes. The art of elsctrotyping, says a contemporary, already applied to myriad uses, shows constant evidsnce of progress, especially in tbe successful dsposition for practical purposes of metals that havs hitherto heen considered intractahle. Nickel-plating is uow common, and, while cheaper, is for soms purposes suporior to silver; and there is some reasou to snppose that by the employment of a smail psreentage of some other metal to diminish the brittleness, the rather refractory nature of the nickel coating may be hrought more completely under the control of the hurnisher, in lieu of the polisbing whesl, than is now the case. There are many purposes, however, for whick a plating of iron would be, all things considered, bstter than any of those now familiar in elsctro-metallurgy; and to secure this has occupied tho attention of some foreign experimenters, who have, apparently, been very succossful in thsir efforts. At the late London International Exhibition (1871) were exhibited bank-note plates, medallions, and a page of printingtype, elsctrotyped in iron, by a process devised by M. Engene Klein, who is at the head of the Chemical Department in the Imperial State Paper Manufactory in St. Petersburg. The advancement of the iron electrotype to a practical success has not heen accomplished witbout the expenditure of much thought and experiment, and many difficulties haye had to be surmounted; but the scisntific interest which attachsd to the new development, and the eminently useful applications of which he saw it was susesptible, especially in the departments of engraving and printing, stimulated M. Klein to continus his experiments, against what appeared to hs almost or quite insurmountahle hindrances. His starting point was the steeling of sngraved copper-plates, which process was effected in a bath composed of chlorate of ammonia and iron, to which he added a small quantity of glycerine. On leaving the bath the iron is as hard as tempered steel and very hrittls. Reheated it loses much of its hardness, and hscomes mallsable at cherry red, when it may be cut with the graver as readily as soft steel. Of the importance of the practical application of the process there can he no douht whatever. By replacing plates of copper by those of iron, greater facilities will he afforded for producing publications, works of art, and especially hank-notes and checks. Iron electrotype plates are found to be almost indestructihle in the process of printing, while copper soon wears out— much sooner, in fact, than wood. A late issue of Engineering gives in detail the expsrimonts through which this important process has advanced toa condition of high practical value.