Volume 17 (1868) (428 pages)

The Mining and Scientific Press. Mechanical, Melting and Casting Wrought Iron. An experiment was tried some years ago, at the Mersey Stecl Works, in England, of fusiag wrought iron, with the view of casting iato snch shapes as cranks, eross-heads, aad other formsdiflicult to forge, but which were required by engineers. Tho oxperiuient succeeded admirably, so far as to obtain most excellent castings; but it was found that such deterioration took place in the structure of theiron, when passing from a fiuid to a solid state, as to render cast wrought iron but little snperior to ordinary east iron. These experiments were undertaken while Mr. Bessemer was engaged in his early oxperiments, and it was especially noticed that the fracture of the cast wrought iron prosouted a very similar appearance to the Bessemer steel] ingots when broken. It was found that crystallization took place iu the same mannorduring the cooling of wrought iron, as ordinarily takes place with othor substances when passing from a fluid toa solid state. The heat required for melting wrouglit iron is vastly greater than that required for melting east iron; aud is obtained only with greatdifliculty, even in the best constructed furnaces, Scrap iron of the best qnality was nsed for these castings. Although tho experiments resulted in au utter failure, so far as the main object of their undertaking was concerned, they neyertheless led to tho development of a fact of much in portance in connection with heavy forging operations. The idea was cnrreut at this time, that large masses of wrought iron, from long continued heating, have a tendency to erystallize, and lose the fihrous quality peculiar . to that kind of iron—an idea under which Mr. Nasmyth’s experiments for construct ing forged cannon of large size, had just before been abandoned. It was supposed that the great length of time employed in heating such large masses, and subsequently in forging and shaping them, gradually produced the change from a fihrousto crystalline texture. The experience gained in making wrought iron castings, during the experiments at the Mersey Stecl Works, developed the frue cause of the crystallization of such iron, wheu brought about hy furuace operations ; and the subsequent successful production of forged masses, much greater in size than those operated ou by Mr. Nasmyth, have practically demonstrated tho incorrectness of the former theory. Tho real cause of the change in the texture of the iron is due to overheating. In heating such large masses, the fires are urged too rapidly, so that the outside first, and subsequently the whole mass of the forging, is reduced to a pasty or semi-fluid condition. When such a degree of heat is attained, the fihrous structure is inevitahly destroyed, and, in the process of cooling the mass, crystallization inevitably takes place. The iron, under such circumstances, is sometimes said to be “‘hurned.” The degree of heat which will produce this change is much greater than that required for forging. True, wrought iron, when subjected for a long time to constant alternations of heat and cold, will lose its fibrous structure, much as it does when suhjected, for a lengthy period, to constant vibration—for heat is nothing but another mode of setting the particles of iron in motion—but a gsimple continued condition of heat, however great, short of complete or partial fusion, will never produce any material change in the structure of wrought iron. Inon ror Guinpino Purrosrs.—Grindiug with a cast iron wheel at high velocity is a process successfully conducted at many shops, and which has heen found to be both economical and efficient. 83 Tenacity oF Meraus axp ALLoys.—The following experiments have been made to test the tenacity of metals and alloys, with the annexed results. The tension was ohtained by tho uso of a winch, and measured by a spring balance. ‘The wires used were donble, gauge No. 23: Breaking strain for dow)! wires, ander 7 Ih Iron. . Tin-lend Tila copper all Copper-tin alloy (12 Gold copper aifoy. Silver-platiuunt alloy MCC sever eurctscace cereus Testixo Streams Bormers,—Prof. 8S. W. Robinson, of tho University of Michigan, proposes to the engineer who wishes to dotermine the pressure to which his boiler ean bo worked with safety, the following very simple process: Lettho boiler be filled entircly full of cold water, even to tho throttle and safety valves, and all closed tight to prevent any escape. Now, by lightfing a fire under the boiler, tho water will be gradually expanded, and producea pressure suflicient even to rupture tho iron before the temporaturo of the wator arrives at the boiling point. While the pressure is increasing, let tho steam gauge or pressure indicator be watched; and when the test pressure, which may be twice or more times as great as the working pressuro, is reached, a portion of the water may bo allowed to escape, and the pressuro reduced. The pressure results from the fact that water expands more by heat than iron, at a corresponding temperature. The process given above is atteuded with as much safety as tbe use of the hydrostatie press, unless the water be heated over 212° Fah,, which would not be required unless the hoiler leaks. Below this temperature no disastrous cousequences wonld follow, even if the boiler should be torn asuuder, inasmuch as explosions result from the sudden expansiou of gases or vapors. Sctentifie Miscellany. CuAaMPaGse, ETC., From PerRoLevs.— The fact is well kuown that Berthelot, long since, has succeeded iu forming alcohol from tho nnion of olifiant gas with water. Later experiments with the marsh gas sorics of hydrocarbons havo also resulted iu tho production of an alcoholic beverage. it should bo known that all productions of this character, from inorganio substances, although identical in composition with thoso derived from organisms, novertheless possess certain properties quite unlike the latter—and properties, too, which totally unfit them for being taken into the stomach. In these days of adulterations, however, it may be useless fo warn those who may requiro alcohol for medicinal purposes against the use of any decoctions containing spirit not made from sugar, grain, or the grape, from the fact that the real safeguard against this class of adulterations lies in the circumstance that no chemist has yet succeeded in producing from hydrocarbons, aleohol at as low cost as it can be made from Indian corn; and further, in the probability that the large area of land now being devoted to vineyards will result in the production of mild wines much cheaper than “doctored” dilutions of eorn whisky, constituting the imitation. Foruation or DEnprrres,—At a recont mecting of the Royal Geological Society of Ireland, Dr. Emerson Reynolds read a paper ‘Ou tho Formation of Dendrites;” an abstract of which we find published in the Loudon Chemical News. He had some years since noticed that when solutions of salts, ete., were placed npon a plate of elean glass, and the glass placed between/the poles of a Rubmkorff’s coil, the salts gradually work Tuer Loss or Power by THE Cranx.—The erank is simply a mechanical medium of transmitting motion, or rather of transmitting tho direction of powor. No loss of} the power has ever beeu discovered by the . uso of this means, and no real advantage) gained by the substitution of other means. of changing rotary into rectilinear motion, or vice versa. Practically, the speeulative objections agaiust the crank with the experiments based on them have never produced auy device superior. The continued hattle carried on against the crank, as a means to the end in view, has always ended in the disconititure of the aggressor; the hest method would seem to he to produce a new device and prove its superiority to the crank. The discovery will be welcomed by every earnest and honest mechanic. Corrrr anD Iron may be smelted together in almost all proportious, but it appears to he douhtful whether any homogeneous alloys can be produced. A small} quantity of iron, added to hronze or brass, . causes a considerable increase in tenacity. Malleable iron or steel, containing copver to the extent of 1.45 or 0.5 per cent. shows symptoms of red shortness, which become decided with a larger quantity. Ratuway Resistance.—The resistauce of a railway truck is ahout 7 Ibs. per ton of gross load on a level ; on an incline of Lin 20 the resistance per ton will be 7 Ibs. and one-twenticth of the load ; on an incline of Lin 30 it will he 7 lhs. and one-thirtieth of} the load, and soon. At a fair walking pace a horse can maintain a steady pull of 180 lbs. to 200 Ihs, on his traces. Jor a short distance he can pnll much more than 200 lbs. Worxine Incurmep Pianzs,—Within the last few years rolled hoop iron has heen substituted for wire ropes on some of the inclined railroad planes, in the Atlantic States, and have been found to work well. They appear to possess quite as much durahility as the ropes, while the first cost is much less. Serer Iron Canreys. — Minneapolis, Minn., has produced a sheet iron chimney over the surface of the glass in henutiful moss-like forms, which in many cases were characteristic of the componud contained in solution—the state of dilution at the same time having cousiderahle influence. The author proposed to call them ‘electric cohesiou figures.” To produce them we will say thut a drop of a solution of cyanide of potassium is pnt in the center of a plate of glass, which is then placed npon a sheet. of tin-foil. One pole of the coil is then brought into contact with the foil (it is immaterial which), and the other pole is placed in the center of the drop, immediately on passing the current tho solution begins to creep over the surface of the glass in mosslike convolutious. The dendritic markings on minerals, the author helieved, were formed uuder a similar condition. He exhibited a heautiful manganous dendrite taken out of the muscum. It was a’slab of concoidal limestone, and in Dr. Reynold’s opinion illustrated his electrical explanation conclusively. There was originally a flaw in the limestone which was exactly at right angles with the plane of cleavage. Through these flaws, as was evident hy the marks, the manganous solution had percolated, and had perhaps ultimately been the means of making the stone part in two, not, however, iu the direction of the flaws, hut in the plane of cleavage. The dendrites which were formed upon the surface, in this case were produced from the well known fact, that the two surfaces, at the instant of their separation, are in opposite electrical conditions, This phenomena may he illustrated to a certain extent, hy insertiug a drop of the fluid into the interstices of a the plate, the dendritic forms are shown. To fix them, the author dusts some finely dried pigment over the surface of the still moist plate, and then fixes this by some transparent varnish. Tue Scrence or Frorr Syrurs.—There is a fact of considerable importance which should he considered by persons engaged in preparing prescrves: Cane sugar, by long hoiling, is turned into grape sugar, and thus loses one-third of its sweetucss. Grape sugar is less soluble than cane sugar, and when fruit juice has been sweetened and boiled for a long time, the grape sugar separates in the form of white crystals, and the juice is found to be deficient in sweetness. which is made of three sheet iron cylinders, the space between the outer and second one being filled with ashes, thus securiug safety from fire. It is lightcr and safer than brick. being bnilt at Ballston, N. Y. hoiled hy itself until brought to the proper consistence, and after it has become lukewarm, add the required quantity of white or loaf sugar. It will dissolve quite readily, and two important ohjects will be attained: First, a saving of sugar; second, from any of the effects of fermentation. plate of mica, and then, on suddenly parting. to obviate this, let the fruit juice he! Coton or Sux-Spors,—Before the Man“. chester Philosophical Society, at a meeting held April 14th, 1868, Mr. S, Broughtou said that, on recently observing with high powers a gronp of fine spots on the snu, one of which was of considerable magnitnde, it occurred to him to remoye the dark glass, and by keeping tho eyo much beyond the foens of the heating rays, and at such a distance that the spot ulmost filled the apparent field of the eye-piece, to see if any phonomona, could bo observed different from those seen tarough the dark glass. Tho spot was at oneo scen to bo of a dark red ; but thinking this porhaps might bo from the strong eontrast of color, he attached a disk of plaster of paris to the teloscope, and projected tho image of the spot on it. On looking at this with a eommou pocket magnificr, the image was ohserved to bo a dark blood red, althongh the observatory was not darkened, and the disk merely shielded from the direct rays by an intervoning obaque suhstance. If these observations are confirmed, it will oorroborate the opinion long held that the spots are not black, but appear so by contrast, and, as it would seem, from the intervention of the colored glass. Sizp or THE Srars.—How large are the stars, and are thoy alike, or do thoy differ in size? Itused to be conjectured that they are of somewhat similar magnitude, presumably about as great asoursun, and that the differenees of apparent size are due to differences of distance; but when astronomers came to discover that some of the smaller stars are’nearest to our system, this idea fell to the ground. A German computer has now, however, ealculated the actual dimensions of one particular star, and finds that its mass is rather more than three times that of thesun. The star in question is of less than the fourth maguitude—a eomparatively small one. What, then, must be the size of those of the Sirius and Aldeharan class? The reason of its selection for this determination was, that it is one of the components of what is ealled a biuary system—two stars revolving about each other, like sun and planet—and the motion of the memhers of such a system afford data for the computation. The star’s distance from us is a million and a quarter times that of the earth from the sun, so that light takes twenty years to travel hither from it. Aorion or Water on Leap.—Prof. Bottger, inquiring into the cause of the action of distilled water on lead, has found it to be due to the presence of carhonate of ammonia, and not, as is usually ascribed, to the air dissolved in the water. After haying heen boiled fora time, distilled water will not attack the lead until after 2 considerable exposure, when a reahsorption of ammonia and carhonic acid from the air where they are always present, may he supposed to have taken place. Bottyer has further found that the alloying of the lead with a small amount of tin protects the former from being acted upon, and this fact suggests the advantage of purposely introducing a little tininto the metal from which lead piping is to he manufactured. Sincuuar Faor.—The Engineer notices a singular fact in relation to the behavior of the steam engine employed to drive one of Mr. Wilde’s electro-magnetie engines. It appears that whenever pieces of iron rods or wires are placed in the circuit to he heated, the engine slackens speed when the metal hegius to redden, the resistance to the action of the engine perceptibly inereases in proportion as the heat of the metal increases, aud it is only hy the constant care of the engineer that a uniform rate of motion can he secured. Tar Lava or Vesuvius. —M. Silvestri observed the eruption of Vesuvtus in December last at maximum activity, and analyzed many of its volcanic products. The lava is dark gray, and sometimes greenish or reddish on the surface, has a crystalline structure, and exerts an energetic action on the magnetic needle. He classifies the lava in three kinds, varying in density from 2.46 to 2.81. One compact variety contained about two per cent. of water. Three distinct sublimates were found composed mainly of chloride of potassium and sodium and traces of copper. The greenish-brown suhlimate coutained 9.85 pex cent. of copper. New Crmican Discovertes.—Dr. Hoffmann has announced the discovery of a new acid, which hears the same relatiou to napthaliue that acetic acid bears fo marsh-gas, A short time since the same eminent chemist communicated to the Royal Society the A ONE-HORSE powcr paper steamboat is. the actual preservation of the fruit free! discovery of ‘“‘the mustard oil of the ethyl series,”

The Mining and Scientific Press. Mechanical, Melting and Casting Wrought Iron. An experiment was tried some years ago, at the Mersey Stecl Works, in England, of fusiag wrought iron, with the view of casting iato snch shapes as cranks, eross-heads, aad other formsdiflicult to forge, but which were required by engineers. Tho oxperiuient succeeded admirably, so far as to obtain most excellent castings; but it was found that such deterioration took place in the structure of theiron, when passing from a fiuid to a solid state, as to render cast wrought iron but little snperior to ordinary east iron. These experiments were undertaken while Mr. Bessemer was engaged in his early oxperiments, and it was especially noticed that the fracture of the cast wrought iron prosouted a very similar appearance to the Bessemer steel] ingots when broken. It was found that crystallization took place iu the same mannorduring the cooling of wrought iron, as ordinarily takes place with othor substances when passing from a fluid toa solid state. The heat required for melting wrouglit iron is vastly greater than that required for melting east iron; aud is obtained only with greatdifliculty, even in the best constructed furnaces, Scrap iron of the best qnality was nsed for these castings. Although tho experiments resulted in au utter failure, so far as the main object of their undertaking was concerned, they neyertheless led to tho development of a fact of much in portance in connection with heavy forging operations. The idea was cnrreut at this time, that large masses of wrought iron, from long continued heating, have a tendency to erystallize, and lose the fihrous quality peculiar . to that kind of iron—an idea under which Mr. Nasmyth’s experiments for construct ing forged cannon of large size, had just before been abandoned. It was supposed that the great length of time employed in heating such large masses, and subsequently in forging and shaping them, gradually produced the change from a fihrousto crystalline texture. The experience gained in making wrought iron castings, during the experiments at the Mersey Stecl Works, developed the frue cause of the crystallization of such iron, wheu brought about hy furuace operations ; and the subsequent successful production of forged masses, much greater in size than those operated ou by Mr. Nasmyth, have practically demonstrated tho incorrectness of the former theory. Tho real cause of the change in the texture of the iron is due to overheating. In heating such large masses, the fires are urged too rapidly, so that the outside first, and subsequently the whole mass of the forging, is reduced to a pasty or semi-fluid condition. When such a degree of heat is attained, the fihrous structure is inevitahly destroyed, and, in the process of cooling the mass, crystallization inevitably takes place. The iron, under such circumstances, is sometimes said to be “‘hurned.” The degree of heat which will produce this change is much greater than that required for forging. True, wrought iron, when subjected for a long time to constant alternations of heat and cold, will lose its fibrous structure, much as it does when suhjected, for a lengthy period, to constant vibration—for heat is nothing but another mode of setting the particles of iron in motion—but a gsimple continued condition of heat, however great, short of complete or partial fusion, will never produce any material change in the structure of wrought iron. Inon ror Guinpino Purrosrs.—Grindiug with a cast iron wheel at high velocity is a process successfully conducted at many shops, and which has heen found to be both economical and efficient. 83 Tenacity oF Meraus axp ALLoys.—The following experiments have been made to test the tenacity of metals and alloys, with the annexed results. The tension was ohtained by tho uso of a winch, and measured by a spring balance. ‘The wires used were donble, gauge No. 23: Breaking strain for dow)! wires, ander 7 Ih Iron. . Tin-lend Tila copper all Copper-tin alloy (12 Gold copper aifoy. Silver-platiuunt alloy MCC sever eurctscace cereus Testixo Streams Bormers,—Prof. 8S. W. Robinson, of tho University of Michigan, proposes to the engineer who wishes to dotermine the pressure to which his boiler ean bo worked with safety, the following very simple process: Lettho boiler be filled entircly full of cold water, even to tho throttle and safety valves, and all closed tight to prevent any escape. Now, by lightfing a fire under the boiler, tho water will be gradually expanded, and producea pressure suflicient even to rupture tho iron before the temporaturo of the wator arrives at the boiling point. While the pressure is increasing, let tho steam gauge or pressure indicator be watched; and when the test pressure, which may be twice or more times as great as the working pressuro, is reached, a portion of the water may bo allowed to escape, and the pressuro reduced. The pressure results from the fact that water expands more by heat than iron, at a corresponding temperature. The process given above is atteuded with as much safety as tbe use of the hydrostatie press, unless the water be heated over 212° Fah,, which would not be required unless the hoiler leaks. Below this temperature no disastrous cousequences wonld follow, even if the boiler should be torn asuuder, inasmuch as explosions result from the sudden expansiou of gases or vapors. Sctentifie Miscellany. CuAaMPaGse, ETC., From PerRoLevs.— The fact is well kuown that Berthelot, long since, has succeeded iu forming alcohol from tho nnion of olifiant gas with water. Later experiments with the marsh gas sorics of hydrocarbons havo also resulted iu tho production of an alcoholic beverage. it should bo known that all productions of this character, from inorganio substances, although identical in composition with thoso derived from organisms, novertheless possess certain properties quite unlike the latter—and properties, too, which totally unfit them for being taken into the stomach. In these days of adulterations, however, it may be useless fo warn those who may requiro alcohol for medicinal purposes against the use of any decoctions containing spirit not made from sugar, grain, or the grape, from the fact that the real safeguard against this class of adulterations lies in the circumstance that no chemist has yet succeeded in producing from hydrocarbons, aleohol at as low cost as it can be made from Indian corn; and further, in the probability that the large area of land now being devoted to vineyards will result in the production of mild wines much cheaper than “doctored” dilutions of eorn whisky, constituting the imitation. Foruation or DEnprrres,—At a recont mecting of the Royal Geological Society of Ireland, Dr. Emerson Reynolds read a paper ‘Ou tho Formation of Dendrites;” an abstract of which we find published in the Loudon Chemical News. He had some years since noticed that when solutions of salts, ete., were placed npon a plate of elean glass, and the glass placed between/the poles of a Rubmkorff’s coil, the salts gradually work Tuer Loss or Power by THE Cranx.—The erank is simply a mechanical medium of transmitting motion, or rather of transmitting tho direction of powor. No loss of} the power has ever beeu discovered by the . uso of this means, and no real advantage) gained by the substitution of other means. of changing rotary into rectilinear motion, or vice versa. Practically, the speeulative objections agaiust the crank with the experiments based on them have never produced auy device superior. The continued hattle carried on against the crank, as a means to the end in view, has always ended in the disconititure of the aggressor; the hest method would seem to he to produce a new device and prove its superiority to the crank. The discovery will be welcomed by every earnest and honest mechanic. Corrrr anD Iron may be smelted together in almost all proportious, but it appears to he douhtful whether any homogeneous alloys can be produced. A small} quantity of iron, added to hronze or brass, . causes a considerable increase in tenacity.

Malleable iron or steel, containing copver to the extent of 1.45 or 0.5 per cent. shows symptoms of red shortness, which become decided with a larger quantity. Ratuway Resistance.—The resistauce of a railway truck is ahout 7 Ibs. per ton of gross load on a level ; on an incline of Lin 20 the resistance per ton will be 7 Ibs. and one-twenticth of the load ; on an incline of Lin 30 it will he 7 lhs. and one-thirtieth of} the load, and soon. At a fair walking pace a horse can maintain a steady pull of 180 lbs. to 200 Ihs, on his traces. Jor a short distance he can pnll much more than 200 lbs. Worxine Incurmep Pianzs,—Within the last few years rolled hoop iron has heen substituted for wire ropes on some of the inclined railroad planes, in the Atlantic States, and have been found to work well. They appear to possess quite as much durahility as the ropes, while the first cost is much less. Serer Iron Canreys. — Minneapolis, Minn., has produced a sheet iron chimney over the surface of the glass in henutiful moss-like forms, which in many cases were characteristic of the componud contained in solution—the state of dilution at the same time having cousiderahle influence. The author proposed to call them ‘electric cohesiou figures.” To produce them we will say thut a drop of a solution of cyanide of potassium is pnt in the center of a plate of glass, which is then placed npon a sheet. of tin-foil. One pole of the coil is then brought into contact with the foil (it is immaterial which), and the other pole is placed in the center of the drop, immediately on passing the current tho solution begins to creep over the surface of the glass in mosslike convolutious. The dendritic markings on minerals, the author helieved, were formed uuder a similar condition. He exhibited a heautiful manganous dendrite taken out of the muscum. It was a’slab of concoidal limestone, and in Dr. Reynold’s opinion illustrated his electrical explanation conclusively. There was originally a flaw in the limestone which was exactly at right angles with the plane of cleavage. Through these flaws, as was evident hy the marks, the manganous solution had percolated, and had perhaps ultimately been the means of making the stone part in two, not, however, iu the direction of the flaws, hut in the plane of cleavage. The dendrites which were formed upon the surface, in this case were produced from the well known fact, that the two surfaces, at the instant of their separation, are in opposite electrical conditions, This phenomena may he illustrated to a certain extent, hy insertiug a drop of the fluid into the interstices of a the plate, the dendritic forms are shown. To fix them, the author dusts some finely dried pigment over the surface of the still moist plate, and then fixes this by some transparent varnish. Tue Scrence or Frorr Syrurs.—There is a fact of considerable importance which should he considered by persons engaged in preparing prescrves: Cane sugar, by long hoiling, is turned into grape sugar, and thus loses one-third of its sweetucss. Grape sugar is less soluble than cane sugar, and when fruit juice has been sweetened and boiled for a long time, the grape sugar separates in the form of white crystals, and the juice is found to be deficient in sweetness. which is made of three sheet iron cylinders, the space between the outer and second one being filled with ashes, thus securiug safety from fire. It is lightcr and safer than brick. being bnilt at Ballston, N. Y. hoiled hy itself until brought to the proper consistence, and after it has become lukewarm, add the required quantity of white or loaf sugar. It will dissolve quite readily, and two important ohjects will be attained: First, a saving of sugar; second, from any of the effects of fermentation. plate of mica, and then, on suddenly parting. to obviate this, let the fruit juice he! Coton or Sux-Spors,—Before the Man“. chester Philosophical Society, at a meeting held April 14th, 1868, Mr. S, Broughtou said that, on recently observing with high powers a gronp of fine spots on the snu, one of which was of considerable magnitnde, it occurred to him to remoye the dark glass, and by keeping tho eyo much beyond the foens of the heating rays, and at such a distance that the spot ulmost filled the apparent field of the eye-piece, to see if any phonomona, could bo observed different from those seen tarough the dark glass. Tho spot was at oneo scen to bo of a dark red ; but thinking this porhaps might bo from the strong eontrast of color, he attached a disk of plaster of paris to the teloscope, and projected tho image of the spot on it. On looking at this with a eommou pocket magnificr, the image was ohserved to bo a dark blood red, althongh the observatory was not darkened, and the disk merely shielded from the direct rays by an intervoning obaque suhstance. If these observations are confirmed, it will oorroborate the opinion long held that the spots are not black, but appear so by contrast, and, as it would seem, from the intervention of the colored glass. Sizp or THE Srars.—How large are the stars, and are thoy alike, or do thoy differ in size? Itused to be conjectured that they are of somewhat similar magnitude, presumably about as great asoursun, and that the differenees of apparent size are due to differences of distance; but when astronomers came to discover that some of the smaller stars are’nearest to our system, this idea fell to the ground. A German computer has now, however, ealculated the actual dimensions of one particular star, and finds that its mass is rather more than three times that of thesun. The star in question is of less than the fourth maguitude—a eomparatively small one. What, then, must be the size of those of the Sirius and Aldeharan class? The reason of its selection for this determination was, that it is one of the components of what is ealled a biuary system—two stars revolving about each other, like sun and planet—and the motion of the memhers of such a system afford data for the computation. The star’s distance from us is a million and a quarter times that of the earth from the sun, so that light takes twenty years to travel hither from it. Aorion or Water on Leap.—Prof. Bottger, inquiring into the cause of the action of distilled water on lead, has found it to be due to the presence of carhonate of ammonia, and not, as is usually ascribed, to the air dissolved in the water. After haying heen boiled fora time, distilled water will not attack the lead until after 2 considerable exposure, when a reahsorption of ammonia and carhonic acid from the air where they are always present, may he supposed to have taken place. Bottyer has further found that the alloying of the lead with a small amount of tin protects the former from being acted upon, and this fact suggests the advantage of purposely introducing a little tininto the metal from which lead piping is to he manufactured. Sincuuar Faor.—The Engineer notices a singular fact in relation to the behavior of the steam engine employed to drive one of Mr. Wilde’s electro-magnetie engines. It appears that whenever pieces of iron rods or wires are placed in the circuit to he heated, the engine slackens speed when the metal hegius to redden, the resistance to the action of the engine perceptibly inereases in proportion as the heat of the metal increases, aud it is only hy the constant care of the engineer that a uniform rate of motion can he secured. Tar Lava or Vesuvius. —M. Silvestri observed the eruption of Vesuvtus in December last at maximum activity, and analyzed many of its volcanic products. The lava is dark gray, and sometimes greenish or reddish on the surface, has a crystalline structure, and exerts an energetic action on the magnetic needle. He classifies the lava in three kinds, varying in density from 2.46 to 2.81. One compact variety contained about two per cent. of water. Three distinct sublimates were found composed mainly of chloride of potassium and sodium and traces of copper. The greenish-brown suhlimate coutained 9.85 pex cent. of copper. New Crmican Discovertes.—Dr. Hoffmann has announced the discovery of a new acid, which hears the same relatiou to napthaliue that acetic acid bears fo marsh-gas, A short time since the same eminent chemist communicated to the Royal Society the A ONE-HORSE powcr paper steamboat is. the actual preservation of the fruit free! discovery of ‘“‘the mustard oil of the ethyl series,”