Volume 34 (1877) (434 pages)

MINING AND SCIENTIFIC PRESS. April 14, 1877.] . 6, : i i, hii [ECHANICAL ‘PROGRESS. i we) The Strength of Riveted Joints. Wt has been suspected for a long time by percy. have investi; 1 the strength of rivl juints that the ordinarily received data reing thereto cannot be relied upon implicitly, . that for : reason, not te 4 one or understood, such joints would often break at gtraine than calculation would indiAy their ultimate strength. ‘Tho basis, BAY Bpdteon! Gazette, on which the data din auch calculations rested was the exSof Fairbairn, which were in some reta very unsatisfactory. ‘These showed that Patrength of u single riveted joint wax equal to about 6 of the solid plate, and a doubleivoted joint from 70) te 72. Nevertheless joints failed at times wheu Fairbairn’s deduce. tions showed they ought nut to fail, and boilers from time immemorial have blown up which ‘apparently had no sufficient logical or matliemiatical reason to justify their conduct. Such au explosion tovk place in Blackburn in Engie 1874, and excited a keen interest and led to hot disputes amony engineers afterwards. In order to sat some of ‘these disputed points at rest, Mr. R. K. Longridge, engineer to the a Boiler Insurance Company, institnted a ries of experiments on the strength of riveted joints, which have been carried out by the celebrated Mr. 1). Kirkaldy, whose investigations of theatrength of materials have now become so noted, and the results and accuracy of whose investigations will not be questioned. _ The details of these experiments have not yet been fully made public, but in his last report to the Steam Boiler Insurance Company, Mr. ‘Langridge gives some of the results of these experiments, These, ina vondensed form, apparently, are published in a recent number of the Engineer (Feb, 23d, 1877). The conelusions deduced therefrom may be briefly stated to be, that boiler seams are not nearly as strong as Mr. Fairbairn thought and many of us believed they wery. In 28 experiments with singleriveted lap joints, the average of the strength of the riveted seams, compared with that of the plate, was only 42.2’, the lowest being 38.9%, and the highest 50.67). The average of 20 experiments with donble-riveted lap joints was (0.2 of the solid plate, the highest being 66.1, and the lowest 53.27;. The average of 16 experiments with single-riveted butt joints was 57.5,/, the highest 66.1): and the lowest 51.5 /. With double-riveted butt joints the averaye of 20 experiments way 66:7, the highest 67.2°7 and the lowest 61.6.4. Experiments were also made with ‘diagonal joints,” that is, joints which instead of being at right angles with the sides of the test piece were placed inclined at an angle of 45°. A single-riveted lap joint of this kind gave a atrenyth of 60.1'. of the solid plate, and a double-riveted lap joint of this kind a strength of 69.2. The strongest of all the rivets was one which is described as a *‘double-riveted butt joint, breaking joint ¥ holeor TH in.” Wrhiat is mvant thereby is not apparent, but this joint gave a strength of 74.7. of the solid plate. The plates varied in thickness from onefourth to one-half inches, and the rivets from one-half inch to 15-16 inches in diameter. One noteworthy fact was developed hy the experiments. Some of the plates in which the rivet holes were punched were annealed and others unannealed when tested. Whether the annealing was done after or before the rivet holes were punched is not stated, but the great increase in strength is very apparent all through. Thus in the first experiment given the strength of the seam of the plates which were not aunealed was 38.9/, of the solid plate, whereas those which were annealed gave a percentage of 45.7 of the solid plate. In these two caves the plates were broken, but, what is very singular, in those experiments in which the rivets were sheared, the resistance of the latter seemed to be increased by annealing the plates, which is owing, probably, to the fact that the increased duutility due to the process of annealing permitted the rivets to ‘‘come to a bearing” more perfectly than was possible when the plates were leas ductile. None of the plates in which the holes were drilled were annealed, so that it is impossible to say whether their strength would have bean increased by the same process. But whether the plates were annealed or not, in no case was the strength of a single-nveted joint as high as that given by Fairbairn, that is, 56/ of the solid plate, Loss iv Meran Workrnc.—Last summer we had some articles on the loss of precious metals by vaporization. The same loss is guarded against by Eastern manufacturing establishments. We read in the Hartford Times that on the recent closing up of the Smith & Rogers silver plating concern in New Haven, on its removal to Meriden, the floor of the plating-room was taken up, burned, and the ashes analyzed, with the result of procuring pure silver to the amount of $981. This result is not so strange as appears at first sight. The precious metals are capable of extreme volatilization under heat, becoming mere vapors, which may be condensed, resulting in the production of the metal in a pure form. But even without heat the particles of gold‘and silver are made so exceedingly fine in the processes of the manufacture of aud mlyer yooday whether solid or plated, ge sodeticts for a the material abraded or thrown off in the various manipulations are entirely effectual. Even in the Gover as~~ AcientiFic p ROGRESS. 1D ri gay offices the soot deposited in the ys from the melting of the crude metal is valuable; and bu most manufnctories of articles of guld and silver the preprictors do not allow the workmen to retau their work clothes when worn out but pay for them a price generally sullicient te rocure new garments —an old tattered vest beonging to a bench workman being The Popular Estimate of Chemical Science. If we turn to chemistry, we shall see that while its importance is almost universally recognized, while the number of those who devote +h, valued by his employers, even when worn to Fags, at $20. More Asovr THR Keretey.—The Weatern Manufacturer says: An exchange informs us that the Keeley motor still lives. The old ditliculty of tinding something strony enough to hold the woulda Bo wee developed from a few drops of cold water, seems still to be the moat serious thing in the way of Mr. Keeley’s success. He is now having made, at Chester, Pa., two immense hollow globes of steel, the Iarger of whieh weighs 58,000 pounds, is 36 inches in inside, making the metal inside of the globe nine inches thick, solid steel. This is intended to withstand a pressure of 25,000 pounds to the square inch, The other ball or globe is about half the size of tho la one and will withstand a pressure of half as much. A sphere of this description, manufactured at the same place a few months since, and which was warranted to stand a pressure of 60,000 pounds, burst when 50,000 pounds pressure was put upon it. We shall look with no small degree of interest for the account of the bursting of this immense sphere, for we have no idea that it will stand the test of the wonderful strain to which it is to be subjected. What this sanguine gentleman is going to do with his invention when it is perfected remains to be seen; but it is to be hoped that he will blow nobody up fatally. Antieuity oF Jron.—The oldest pieces of iron (wrought iron} now known are probably the sickle-blade found by Belzoni under the base of a sphinx in Karnac, near Thebes; the blade found by Colonel Vyse, imbedded in the masonry of the (ireat Pyramid; the portion of a cross-cut saw exhumed at Nimrud by Mr. Layarl—all of which are now in the British museum, A wrought bar of Damascus steel was presented by King Porus to Alexander the Great; aud the razor-steel of China for many centuries has surpassed! all European steel in temper and durability of clge. The Hindoos appear to have made wrought? iron directly from the ore, without passing it through the furnace, from time immemorial, and elaborately wrought masses of iron are still found in India which date from the early centuries of the Christian era, PreskRVATION oF BeLrinc.—In order that belting of cotton or linen should have both power, they should be thoroughly soaked in linseed oil varnish. If the belting be new, the varnish may be supplied with a brush, until no more will be taken up, whereupon.it.may.immediately be used without any preparatory drying. After having heen in use for some weeks, a sccond application of the varnish should be put on. Cotton or linen belting thus prepared will neither contract nor stretch, and will always be pliable and unaffected by change of temperature. The adhesion of the belt to the pulley is likewise increased by the varnish, while steam and acid fumes have no effect upon the belting at all. —Maxchinen-Constructeur. Sream ror LumBertnc.—The superiority of steam for general transportation purposes is continually asserting itself. An extensive ]umbering firm, owning a tract of land in Michi some seven miles from their mill, on the Muskegon river, have recently built a railway for the purpose of hauling logs, and find great economy over the use of teams, The iron used is a T rail 25 pounds to the yard, and the engine and cars are light, the latter weighing + 1,700 pounds. About 215,000 feet of logs can be hauled in 12 hours; with four train men— about ten times a8 much.as the same number of men and teams could carry. A New Apprication or PuorocrapHy.—An English exchange states that the Landore Steel Company use photography to’ illustrate the character of the metal manufactured hy them. A plate of wrought iron is placed on a hollow anvil and a small gun-cotton cartridge is expleded on its upper surface, the result being an indentation atl fissures all over the surface. A plate of steel is treated in a similar manner, and when photographs are taken of the two plates the quality of the two metals can be estimated by purchasers in all parts of the world as easily as if they-had witnessed the experiments. Warsine Ratbway CaRRIAGES FROM THE Locvomorive.—We read that all classes of carriages on the Alsace-Lorraine lines are now warmed, the supply of heat being from the boiler of the locomotive. Metallic standpipes are placed in each earriage beneath the seats, connecting with a main running the length of the carriage. Each of these is connected with the next by india-rubber tubing, the whole forming a continuous supply, which the passen-: ers can regulate for themselves, by moving a ever placed on a sector bearing the words cold, warm, hot. diameter on the outside, and 18 inches on the . 4; strength and tlexibility, together with adhesive: Ives to its study is increasing every year, while immense sums of moncy are yearly spent for the building and support of palatial Jaboratories, while the press, recognizing the popular appreciation of the science, furnishes, in ity own peculiar way, brief records of its advance—atill we can point to very little connected with chemistry which, for its elevating influence upon maukind, can be compared with the great physieal truths abeve referred te. That which is caught at and served up for the public is taken from the lower portions of the science, while the higher portions pass on, scarcely if ever coming in conta with the populace. The pubic knows when a new dye is discovered, it knows when the poison has becn found in some strange stomach, it knows when a new milk for babes has been concocted, it knows when precious metals have been detected in the depths of the earth, it knows all these things because it is promptly informed in regard to them, and it is right and good that the information should be given and that these things should be known. Itis plain, however, that a thousand dyes might be discovered, that a thousand murderers might be brought to justice through the aid of the chemist, that varieties innumerable of milk for babes might be concocted, or that mines upon mines of gold might be unearthed without the slightest ennobling or elevating influence being exerted upon the mass of mankind. All these things would be valuable, undoubtedly, but their value would be of a very material kind. It is certain that this material value is that which is most easily recognized, which appeals most directly to the public, and hence plainly, in the public mind, the importance of chemistry is measured by the standards of this value. The reputations of chemists, too, depend upon the greater or less extent to which iy devote themselves to practical questions. He who is frequently on the stand to testify in regard to cases of pvisoning, he who succeeds in presenting to the world some new compound which can be used practically, he who detects impurities in our food or tells us of poisons where their presence must be of importance to us— this man is, to the public, the chemist. Ask 99 men out of 100 what a chemist is, and they will give a definition of one who practices the art of chemigtry, rather than one who is devoted to the science of chemistry.—Prof. Remsen, in Popular Science Monthly. Country Laboratory Apparatus. Some of the grandest discoveries in chemistry and other sciences were made with the rudest home-made apparatus, Although the sciences have now reached such a state of elaboration that few facts perhaps lie near the surface, still there may be much advantage in setting at work a large class of earnest students who are unable to possess themselves of all the vontrivances of a well-appointed laboratory, Asa hint in this direction we take the following from the Chemical News, written by K. T. Hardman, a practi-. eal chemist: The following short escriptiog of an extremely effective, cheap and cleanly substitute for crucible jackets, etc., may be useful, especially to those who, like myself, have occasion to shift their quarters often, and are obliged to work with a necessarily limited laboratory accommodation. The ordinary crucible jacket being made of sheet iron has in reality but one use—to protect the flame from currents of air. The small concentration of heat which it affords may be regarded as nearly nil, since from the nature ef the material and its thinness, radiation takes place very freely. ‘ Another drawback it has is that it soon hecomes rusty or coated with scale. It is not only dirty to handle, therefore, but also presents the inconvenience of dropping some of its scale into the crucible if not carefully manipulated. Then it is an awkward thing to pack, taking u a good deal of space, rusting everything it comes in contact with, and behaving generally in a disagreeable manner; while, as it is not to be obtained in country towns, it may not be left behind. Now an ordinary earthenware flower-pot answers the purpose in every respect. It is the proper shape, and being of a non-conducting material, it in a great measure prevents loss of heat from the burner. It is extremely cleanly to use, and last, but not least, it can be procured in every town or village at the small cost of one halfpenny or so; and there is no necessity to cumber oneself with it when moving. The bottom of the flower-pot has a circular hole. This serves for the introduction of the Bunsen burner. As the supply of air would be insufficient otherwise it will be necessary to enlarge the opening. This can be easily done with a knife and I find it best to cut the aperture nearly in the form of a cross, and not too large. One or two trials will give the happy medium. A current of air is then obtained which not only steadies the flame, but acts in some degree as a blast. The flower-pot may be supported in the ring of a retort stand in the usual way. The chimney is a second flower-pot inverted. To support it the handiest way will be to make three S hooks of stout wire, and having passed the narrow end of th through the ring, fix the rim within the hooks caught on the ring. It will be found convenient to devote a small retort stand permanently to the purpose. This will be very handy, as the upper part can be raised to any desired hight, ——the heat and draft; or can be shifted from sic to side, whenever it is desirable to inspect the —— of the operation going on. aa The — acts admirably as a small furnace for crucible operationa, such as the fusion of silicates with carbonate of soda—as in the analysis of rocks; while for rimple ignition of precipitates it renders the flame of a common glass spirit lamp most effective. The size of the flower-pot required will, of course, depend on that of the crucible and of the burner used. I tind the smallest size, three and one-half inches high and about eight inches in diameter at top (internal) most generally useful. The support for the crucible may be either a triangle of wire covered with pipe shank, the end of the wire being bent dfn and formed into hooks so as to hang on the edge of the flower-pot, or three pipe-covered wires sua. pended in the position of the ribs of a crucible jacket. The former is necessary for small crucibles, is . The flower-pot also makes an excellent lampscreen, for steadying and concentrating the flame under evaporating basins, etc.; of course a sufficient interval must be kept between the pot and the basin else the light will be extinguished. A small flower-pot with wire gauze tied over the top is a very effective low temperature lam when the gas is lighted below the gauze. the gas is lighted above the gauze we have a capital argand lamy giving a large, clear blue flame. In the latter case a common burner can be used, a consideration when Bunsen’s are all temporarily occupied or not available. After atime the pots become cracked from the heat, but as they are easily replaced this does not matter, and even when cracked they will often hold out for a considerable time. Fireclay flower-pots made rather thick would, however, afford a really good and cheap portable furnace, It has just occurred to me that by placin the flower-pot inside another just large enou, to encase it, loss of heat by radiation would ie effectually checked. é Solid Water. Prof. Guthrie, F.R.S., gave a lecture recently at the Royal Institution on ‘Solid Water.” Tron says: He began with the remark that those things which are im their nature most abundant, are, in fact, the most exceptional. After a few other illustrations, he pointed out that water, which is so very common, is unusual, and shows egregiousness in its properties, Cast radiant heat on it, it arrests that heat; apply heat and it not only conducts it, but is preeminent among compound elements as a copductor. Drops of water are the largest of drops of any fluids, and hold together ye est, i reflects light least. Water may be solid from the abstraction of heat, and in association with other hodies it may become solid, In the latter case it is only conventionally called solid, and it might he better to call it fixed. It was especially the ‘‘fixing” of water in compounds of water and salts that formed the subject of the lecture. About two years ago Prof, Guthrie proposed the term cryohydrates for the hydrates ef those crystalline bodies which can exist solid only at a temperature below the freezing point of water. The study of the eryohydrates opens up a wide field of research of which we are but yet on the threshold, A number of experiments were shown and tables of results so far obtained in working with different compounds were exhibited. The actual production of the crychydrates of bichromate of potash and sulphate of copper was shown on a small scale between sheets of glass in front.of a lantern, the gradual growth being watched on the screen on which the images were projected. We can hardly yet tell to what practical uses these studies may lead, but this is already seen, that while the eryohydrate of common salts used as a freezing mixture maintains a temperature of 22° C., there are other cryohydrates that maintain a lower temperature. Speaking of the palwocrystic sea, Prof. Guthrie said he ventured to predict the proportions of the salts there will Bs found different from what they are in other oceans. One fact not accounted for before that these studies have explained is that at 37° C. a mixture of four molecules of water and one of alcohol become solid, but that a mixture either stronger or weaker will not solidify. This explains why the rum of some whaling ships will freeze, and of others it will not. It depends on its strength. In conclusion, Prof. Guthrie spoke of the importance of a careful study of the effects caused by slight differences even in common objects. A Surkine Istanp.—The island of Heligoland, situated in the German ocean, and belonging to Great Britain, is reported to be gradually disappearing. It is now less than a mile in superficial extent; but in 1649 it was four miles in cireumference; in 1300 it measured 45 miles, and in 800, 120 miles. The encroachment of the sea is effected almost entirely from the north-east, owing to the currenta and the direction of the prevailing winds.

MINING AND SCIENTIFIC PRESS. April 14, 1877.] . 6, : i i, hii [ECHANICAL ‘PROGRESS. i we) The Strength of Riveted Joints. Wt has been suspected for a long time by percy. have investi; 1 the strength of rivl juints that the ordinarily received data reing thereto cannot be relied upon implicitly, . that for : reason, not te 4 one or understood, such joints would often break at gtraine than calculation would indiAy their ultimate strength. ‘Tho basis, BAY Bpdteon! Gazette, on which the data din auch calculations rested was the exSof Fairbairn, which were in some reta very unsatisfactory. ‘These showed that Patrength of u single riveted joint wax equal to about 6 of the solid plate, and a doubleivoted joint from 70) te 72. Nevertheless joints failed at times wheu Fairbairn’s deduce. tions showed they ought nut to fail, and boilers from time immemorial have blown up which ‘apparently had no sufficient logical or matliemiatical reason to justify their conduct. Such au explosion tovk place in Blackburn in Engie 1874, and excited a keen interest and led to hot disputes amony engineers afterwards. In order to sat some of ‘these disputed points at rest, Mr. R. K. Longridge, engineer to the a Boiler Insurance Company, institnted a ries of experiments on the strength of riveted joints, which have been carried out by the celebrated Mr. 1). Kirkaldy, whose investigations of theatrength of materials have now become so noted, and the results and accuracy of whose investigations will not be questioned. _ The details of these experiments have not yet been fully made public, but in his last report to the Steam Boiler Insurance Company, Mr. ‘Langridge gives some of the results of these experiments, These, ina vondensed form, apparently, are published in a recent number of the Engineer (Feb, 23d, 1877). The conelusions deduced therefrom may be briefly stated to be, that boiler seams are not nearly as strong as Mr. Fairbairn thought and many of us believed they wery. In 28 experiments with singleriveted lap joints, the average of the strength of the riveted seams, compared with that of the plate, was only 42.2’, the lowest being 38.9%, and the highest 50.67). The average of 20 experiments with donble-riveted lap joints was (0.2 of the solid plate, the highest being 66.1, and the lowest 53.27;. The average of 16 experiments with single-riveted butt joints was 57.5,/, the highest 66.1): and the lowest 51.5 /. With double-riveted butt joints the averaye of 20 experiments way 66:7, the highest 67.2°7 and the lowest 61.6.4. Experiments were also made with ‘diagonal joints,” that is, joints which instead of being at right angles with the sides of the test piece were placed inclined at an angle of 45°. A single-riveted lap joint of this kind gave a atrenyth of 60.1'. of the solid plate, and a double-riveted lap joint of this kind a strength of 69.2.. The strongest of all the rivets was one which is described as a *‘double-riveted butt joint, breaking joint ¥ holeor TH in.” Wrhiat is mvant thereby is not apparent, but this joint gave a strength of 74.7. of the solid plate. The plates varied in thickness from onefourth to one-half inches, and the rivets from one-half inch to 15-16 inches in diameter. One noteworthy fact was developed hy the experiments. Some of the plates in which the rivet holes were punched were annealed and others unannealed when tested. Whether the annealing was done after or before the rivet holes were punched is not stated, but the great increase in strength is very apparent all through. Thus in the first experiment given the strength of the seam of the plates which were not aunealed was 38.9/, of the solid plate, whereas those which were annealed gave a percentage of 45.7 of the solid plate. In these two caves the plates were broken, but, what is very singular, in those experiments in which the rivets were sheared, the resistance of the latter seemed to be increased by annealing the plates, which is owing, probably, to the fact that the increased duutility due to the process of annealing permitted the rivets to ‘‘come to a bearing” more perfectly than was possible when the plates were leas ductile. None of the plates in which the holes were drilled were annealed, so that it is impossible to say whether their strength would have bean increased by the same process. But whether the plates were annealed or not, in no case was the strength of a single-nveted joint as high as that given by Fairbairn, that is, 56/ of the solid plate, Loss iv Meran Workrnc.—Last summer we had some articles on the loss of precious metals by vaporization. The same loss is guarded against by Eastern manufacturing establishments. We read in the Hartford Times that on the recent closing up of the Smith & Rogers silver plating concern in New Haven, on its removal to Meriden, the floor of the plating-room was taken up, burned, and the ashes analyzed, with the result of procuring pure silver to the amount of $981. This result is not so strange as appears at first sight. The precious metals are capable of extreme volatilization under heat, becoming mere vapors, which may be condensed, resulting in the production of the metal in a pure form. But even without heat the particles of gold‘and silver are made so exceedingly fine in the processes of the manufacture of aud mlyer yooday whether solid or plated, ge sodeticts for a the material abraded or thrown off in the various manipulations are entirely effectual. Even in the Gover as~~ AcientiFic p ROGRESS. 1D ri gay offices the soot deposited in the ys from the melting of the crude metal is valuable; and bu most manufnctories of articles of guld and silver the preprictors do not allow the workmen to retau their work clothes when worn out but pay for them a price generally sullicient te rocure new garments —an old tattered vest beonging to a bench workman being The Popular Estimate of Chemical Science. If we turn to chemistry, we shall see that while its importance is almost universally recognized, while the number of those who devote +h, valued by his employers, even when worn to Fags, at $20. More Asovr THR Keretey.—The Weatern Manufacturer says: An exchange informs us that the Keeley motor still lives. The old ditliculty of tinding something strony enough to hold the woulda Bo wee developed from a few drops of cold water, seems still to be the moat serious thing in the way of Mr. Keeley’s success. He is now having made, at Chester, Pa., two immense hollow globes of steel, the Iarger of whieh weighs 58,000 pounds, is 36 inches in inside, making the metal inside of the globe nine inches thick, solid steel. This is intended to withstand a pressure of 25,000 pounds to the square inch, The other ball or globe is about half the size of tho la one and will withstand a pressure of half as much. A sphere of this description, manufactured at the same place a few months since, and which was warranted to stand a pressure of 60,000 pounds, burst when 50,000 pounds pressure was put upon it. We shall look with no small degree of interest for the account of the bursting of this immense sphere, for we have no idea that it will stand the test of the wonderful strain to which it is to be subjected. What this sanguine gentleman is going to do with his invention when it is perfected remains to be seen; but it is to be hoped that he will blow nobody up fatally. Antieuity oF Jron.—The oldest pieces of iron (wrought iron} now known are probably the sickle-blade found by Belzoni under the base of a sphinx in Karnac, near Thebes; the blade found by Colonel Vyse, imbedded in the masonry of the (ireat Pyramid; the portion of a cross-cut saw exhumed at Nimrud by Mr. Layarl—all of which are now in the British museum, A wrought bar of Damascus steel was presented by King Porus to Alexander the Great; aud the razor-steel of China for many centuries has surpassed! all European steel in temper and durability of clge. The Hindoos appear to have made wrought? iron directly from the ore, without passing it through the furnace, from time immemorial, and elaborately wrought masses of iron are still found in India which date from the early centuries of the Christian era, PreskRVATION oF BeLrinc.—In order that belting of cotton or linen should have both power, they should be thoroughly soaked in linseed oil varnish. If the belting be new, the varnish may be supplied with a brush, until no more will be taken up, whereupon.it.may.immediately be used without any preparatory drying. After having heen in use for some weeks, a sccond application of the varnish should be put on. Cotton or linen belting thus prepared will neither contract nor stretch, and will always be pliable and unaffected by change of temperature. The adhesion of the belt to the pulley is likewise increased by the varnish, while steam and acid fumes have no effect upon the belting at all. —Maxchinen-Constructeur. Sream ror LumBertnc.—The superiority of steam for general transportation purposes is continually asserting itself. An extensive ]umbering firm, owning a tract of land in Michi some seven miles from their mill, on the Muskegon river, have recently built a railway for the purpose of hauling logs, and find great economy over the use of teams, The iron used is a T rail 25 pounds to the yard, and the engine and cars are light, the latter weighing + 1,700 pounds. About 215,000 feet of logs can be hauled in 12 hours; with four train men— about ten times a8 much.as the same number of men and teams could carry. A New Apprication or PuorocrapHy.—An English exchange states that the Landore Steel Company use photography to’ illustrate the character of the metal manufactured hy them. A plate of wrought iron is placed on a hollow anvil and a small gun-cotton cartridge is expleded on its upper surface, the result being an indentation atl fissures all over the surface. A plate of steel is treated in a similar manner, and when photographs are taken of the two plates the quality of the two metals can be estimated by purchasers in all parts of the world as easily as if they-had witnessed the experiments. Warsine Ratbway CaRRIAGES FROM THE Locvomorive.—We read that all classes of carriages on the Alsace-Lorraine lines are now warmed, the supply of heat being from the boiler of the locomotive. Metallic standpipes are placed in each earriage beneath the seats, connecting with a main running the length of the carriage. Each of these is connected with the next by india-rubber tubing, the whole forming a continuous supply, which the passen-: ers can regulate for themselves, by moving a

ever placed on a sector bearing the words cold, warm, hot. diameter on the outside, and 18 inches on the . 4; strength and tlexibility, together with adhesive: Ives to its study is increasing every year, while immense sums of moncy are yearly spent for the building and support of palatial Jaboratories, while the press, recognizing the popular appreciation of the science, furnishes, in ity own peculiar way, brief records of its advance—atill we can point to very little connected with chemistry which, for its elevating influence upon maukind, can be compared with the great physieal truths abeve referred te. That which is caught at and served up for the public is taken from the lower portions of the science, while the higher portions pass on, scarcely if ever coming in conta with the populace. The pubic knows when a new dye is discovered, it knows when the poison has becn found in some strange stomach, it knows when a new milk for babes has been concocted, it knows when precious metals have been detected in the depths of the earth, it knows all these things because it is promptly informed in regard to them, and it is right and good that the information should be given and that these things should be known. Itis plain, however, that a thousand dyes might be discovered, that a thousand murderers might be brought to justice through the aid of the chemist, that varieties innumerable of milk for babes might be concocted, or that mines upon mines of gold might be unearthed without the slightest ennobling or elevating influence being exerted upon the mass of mankind. All these things would be valuable, undoubtedly, but their value would be of a very material kind. It is certain that this material value is that which is most easily recognized, which appeals most directly to the public, and hence plainly, in the public mind, the importance of chemistry is measured by the standards of this value. The reputations of chemists, too, depend upon the greater or less extent to which iy devote themselves to practical questions. He who is frequently on the stand to testify in regard to cases of pvisoning, he who succeeds in presenting to the world some new compound which can be used practically, he who detects impurities in our food or tells us of poisons where their presence must be of importance to us— this man is, to the public, the chemist. Ask 99 men out of 100 what a chemist is, and they will give a definition of one who practices the art of chemigtry, rather than one who is devoted to the science of chemistry.—Prof. Remsen, in Popular Science Monthly. Country Laboratory Apparatus. Some of the grandest discoveries in chemistry and other sciences were made with the rudest home-made apparatus, Although the sciences have now reached such a state of elaboration that few facts perhaps lie near the surface, still there may be much advantage in setting at work a large class of earnest students who are unable to possess themselves of all the vontrivances of a well-appointed laboratory, Asa hint in this direction we take the following from the Chemical News, written by K. T. Hardman, a practi-. eal chemist: The following short escriptiog of an extremely effective, cheap and cleanly substitute for crucible jackets, etc., may be useful, especially to those who, like myself, have occasion to shift their quarters often, and are obliged to work with a necessarily limited laboratory accommodation. The ordinary crucible jacket being made of sheet iron has in reality but one use—to protect the flame from currents of air. The small concentration of heat which it affords may be regarded as nearly nil, since from the nature ef the material and its thinness, radiation takes place very freely. ‘ Another drawback it has is that it soon hecomes rusty or coated with scale. It is not only dirty to handle, therefore, but also presents the inconvenience of dropping some of its scale into the crucible if not carefully manipulated. Then it is an awkward thing to pack, taking u a good deal of space, rusting everything it comes in contact with, and behaving generally in a disagreeable manner; while, as it is not to be obtained in country towns, it may not be left behind. Now an ordinary earthenware flower-pot answers the purpose in every respect. It is the proper shape, and being of a non-conducting material, it in a great measure prevents loss of heat from the burner. It is extremely cleanly to use, and last, but not least, it can be procured in every town or village at the small cost of one halfpenny or so; and there is no necessity to cumber oneself with it when moving. The bottom of the flower-pot has a circular hole. This serves for the introduction of the Bunsen burner. As the supply of air would be insufficient otherwise it will be necessary to enlarge the opening. This can be easily done with a knife and I find it best to cut the aperture nearly in the form of a cross, and not too large. One or two trials will give the happy medium. A current of air is then obtained which not only steadies the flame, but acts in some degree as a blast. The flower-pot may be supported in the ring of a retort stand in the usual way. The chimney is a second flower-pot inverted. To support it the handiest way will be to make three S hooks of stout wire, and having passed the narrow end of th through the ring, fix the rim within the hooks caught on the ring. It will be found convenient to devote a small retort stand permanently to the purpose. This will be very handy, as the upper part can be raised to any desired hight, ——the heat and draft; or can be shifted from sic to side, whenever it is desirable to inspect the —— of the operation going on. aa The — acts admirably as a small furnace for crucible operationa, such as the fusion of silicates with carbonate of soda—as in the analysis of rocks; while for rimple ignition of precipitates it renders the flame of a common glass spirit lamp most effective. The size of the flower-pot required will, of course, depend on that of the crucible and of the burner used. I tind the smallest size, three and one-half inches high and about eight inches in diameter at top (internal) most generally useful. The support for the crucible may be either a triangle of wire covered with pipe shank, the end of the wire being bent dfn and formed into hooks so as to hang on the edge of the flower-pot, or three pipe-covered wires sua. pended in the position of the ribs of a crucible jacket. The former is necessary for small crucibles, is . The flower-pot also makes an excellent lampscreen, for steadying and concentrating the flame under evaporating basins, etc.; of course a sufficient interval must be kept between the pot and the basin else the light will be extinguished. A small flower-pot with wire gauze tied over the top is a very effective low temperature lam when the gas is lighted below the gauze. the gas is lighted above the gauze we have a capital argand lamy giving a large, clear blue flame. In the latter case a common burner can be used, a consideration when Bunsen’s are all temporarily occupied or not available. After atime the pots become cracked from the heat, but as they are easily replaced this does not matter, and even when cracked they will often hold out for a considerable time. Fireclay flower-pots made rather thick would, however, afford a really good and cheap portable furnace, It has just occurred to me that by placin the flower-pot inside another just large enou, to encase it, loss of heat by radiation would ie effectually checked. é Solid Water. Prof. Guthrie, F.R.S., gave a lecture recently at the Royal Institution on ‘Solid Water.” Tron says: He began with the remark that those things which are im their nature most abundant, are, in fact, the most exceptional. After a few other illustrations, he pointed out that water, which is so very common, is unusual, and shows egregiousness in its properties, Cast radiant heat on it, it arrests that heat; apply heat and it not only conducts it, but is preeminent among compound elements as a copductor. Drops of water are the largest of drops of any fluids, and hold together ye est, i reflects light least. Water may be solid from the abstraction of heat, and in association with other hodies it may become solid, In the latter case it is only conventionally called solid, and it might he better to call it fixed. It was especially the ‘‘fixing” of water in compounds of water and salts that formed the subject of the lecture. About two years ago Prof, Guthrie proposed the term cryohydrates for the hydrates ef those crystalline bodies which can exist solid only at a temperature below the freezing point of water. The study of the eryohydrates opens up a wide field of research of which we are but yet on the threshold, A number of experiments were shown and tables of results so far obtained in working with different compounds were exhibited. The actual production of the crychydrates of bichromate of potash and sulphate of copper was shown on a small scale between sheets of glass in front.of a lantern, the gradual growth being watched on the screen on which the images were projected. We can hardly yet tell to what practical uses these studies may lead, but this is already seen, that while the eryohydrate of common salts used as a freezing mixture maintains a temperature of 22° C., there are other cryohydrates that maintain a lower temperature. Speaking of the palwocrystic sea, Prof. Guthrie said he ventured to predict the proportions of the salts there will Bs found different from what they are in other oceans. One fact not accounted for before that these studies have explained is that at 37° C. a mixture of four molecules of water and one of alcohol become solid, but that a mixture either stronger or weaker will not solidify. This explains why the rum of some whaling ships will freeze, and of others it will not. It depends on its strength. In conclusion, Prof. Guthrie spoke of the importance of a careful study of the effects caused by slight differences even in common objects. A Surkine Istanp.—The island of Heligoland, situated in the German ocean, and belonging to Great Britain, is reported to be gradually disappearing. It is now less than a mile in superficial extent; but in 1649 it was four miles in cireumference; in 1300 it measured 45 miles, and in 800, 120 miles. The encroachment of the sea is effected almost entirely from the north-east, owing to the currenta and the direction of the prevailing winds.