Volume 17 (1868) (428 pages)

The Mining and scientific Press. Mechantcal, The Steam Engine to be Superseded. In the last edition of Mr. Bonrno's “Treatiso on the Steam Engine,” that eminent engineer expressed the conviction that **the steain engino would pass away hefore many years,”’ and somo other and more economical motor cone into use, in its . stead. Referenco was made to this fact in onr issne of Jnno 18th, 1868. ‘The cngineering world was somewbat startled by this annonneenient; not because its cnunciation was new; bnt heeanse of the high authority which then made tbe utterance. More recently, and withiu a fow weeks, Mr. Bourne has given to the world the first issne of another work, which is to be completed in twenty-four numbers, and wherein the anthor proposes to placo his readers in possession of all the important facts with regard to the progress of the steam ongine from the days of Watt to tho present time, to review the expedients which bave heen proposed as substitutes for the steam engine, and to analyze their respective degrees of merit and promise. The work will also contain practical and illnstrativo drawings anid descriptions of the best forms of air, gas and magnetic engines whieh have already been devised, with suitable commentaries and critical investigations thereof, with the object of deterring from tho adoption of the bad and doubtful, and leading toward the best types now availahle. In alluding to this enunciation, and to the first numher of Mr. Bourne's new work, which had then jnst appeared, the Engineer of Juno 12th, says: We have long hecn acqnainted with many of the views with which the present work will no donbt startle the engineering world, and evidences of this knowledge will bave been ohserved by the attentive reader of our pages to he occasionally cropping out, though we refrain from laying any connected statement of it hefore the pnblie. And if the engineers now awako to the perception of the great fact that the steam engine is slipping from their grasp—tbat it is a moribund expedient, now ahout to be superseded by other motors moro simple and less expensive—it will not he without an effort that they will have heen roused from their ancient somnolency, nor will it he without much intermediate scepticism that they will finally arrive at this salntary conviction: It is prohably to the anticipation of this phase of unbelief that we must attribute the references which Mr. Bourne bas giveu to his past counsels and predictions—under the idea no doubt that his authority would he thereby sniliciently fortified to lend fo necessary weight to his present expositions to ensure their fair and intelligent appreciatiou. Most persons who should venture to appear hefore theengineering public with the announcement that the steam engine was about to be done away with would be in danger of heing set down as ignorant enthusiasts, to whom no heed need be given; but such a conelnsion can bardly be arrived at when the intimation is made by a person already widely known for his intimate acqnaintance with the subject, and when, furthor, it is remembered that he is the author of most of the improvements which have heen introduced into the steam engine since Watt's time, although the real origin of these improvements lias not hitherto heen revealed, ss * ae _ The reflection presses itself upon us, as it will, no douht, do upon our readers, that such a work comin'g from snch a quarter indicatea the impending supersession of the steam engine as a prime mover, and muat be regarded os the beginning of the end. A revolution so enormous has not occurred in our day; and the puhlie curiosity will be intensely excited to learn what superior agent is likely to take the place of the ancient servant now ahout to disappear. An English engineer, now in New York, writes to tho London Exgineer as follows; “The cast iroh here astonishes me. I saw in Brooklyn Navy Yard a cast iron naval gun which had heen hit by a Southern shot about four feet from the muzzle, and the shot had left its mark, impressing the rifliug qnite clearly. There was nota crack upon the surface of the gun, hut the dint was driven right through the thickness of the gun and reproduced in the chase, so that a ae fitting shot could not he fired from it. Ueavy Macuine Toors.—Modern improvements largely require the prodnction of execedingly heavy work, combined with aecuracy of detail and finish. This demand calls, in turn, for machine tools of eomparative magnitudo and weight. Among the principal tools used in tho machino maunfacturing works of Wm. Sellers & Co., of Philadelphia, is a plauer, the capacity of which is, length 45 feet, width 10 feet, hisht 8 feet. ‘The same establishment has a radial drill with a 10-foot projecting swingarm, and a boring drill of 8-foot swing. These works have recently constructed a 24-foot vertical boring and tnrning machino for tho Charlestown Navy Yard, whose total weight is over 72 tons. This machino was inlly deserihed in our eolnmns of March 21st. A second tool of the samo dimensions, and to be constructed aftcr the same patterns, has been ordercd for tho Washington Navy Yard. New Mops or Orenatine Sue Vauves, Isaac Church, Jr., of Norwalk, Conn., has jnst patented au iniproyvemont in oporating tho slide valves of steam enginesand pwnps applicable more specially to direct douhleacting steam pumps, and it will snflice here to regard the same in sneb connection. The improvement is based upon that principlo of action, which has hefore been applied in various forms, in which the valve controlling tho action of the piston is shot or worked alternately in opposite directions by steam admitted throngh the agency of secondary valves that are opened and closed by the motion of the piston. But this invention differs from previous devices of the character referred to, in cansing the main valve to be thrown or shot by steam admitted through puppet valves so arranged as that the engine piston operates in a direct manner upon their stems to lift, and it may also to drop them, and wherehy not only are all outside connections for operating the valves dispensed with, but o most simple and efficient interior valve-operating action or arrangement secured. Harr Currine sy Macuinery.—Hair cutting by machinery is now an accomplished fact, so far as horsesand oxen are concerned, and it seems by no means impossible in the of the human head. M. Nabat has invented a mechanical razor, which, in principle, is something like a lawn-mower. A_ helix, with steel blades tangent toa comb, is made to rotate hy means of a flexihlo chain worked by a lever. One man works the lever, while the “operator” promenades the comb over the body of the animal, regulating the length of hair to be left. hy the inclination of thecomh. It is said that horses and other heasts enjoy being clipped by machinery. It, however, remains to be seen whether humanity will.—Mechanics’ Maga-. Zine, Mr. J. I’. Bennet annonnees that he can remove sulphur and phosphorus from pigiron, during its treatment in the Bessemer process, hy introdncing into the converting vessel carhonie acid gas, either before or with the air blast. He asserts that sulphurons and phosphoric acid are formed at the expense of the carhonic acid gas, the carbon of which is liberated. The gasis produced by acting on hrimstoue by hydrochloric acid, or by burning carbonaccous matter and storing in a gasometer. Suprrroriry oF Amentcan Cast Srerp. Experiments recently mado at the Navy Department, Washington, with cast stecl resulted in favor of an American hrand— that of tho Black Diamond Company, Pittsburg, Pa.—which atond the extraordinary test of 242,100 pounds tensile strength to the sqnare inch, being the highest on record, and showing a superiority over English mannfacturo. Mn. Farrparen in 1840, predicted that, in the course of four or five years, iron would entircly supersede wood in shipbuilding ; and he subsequently gave his opinion that the whole navy of Great Britain must be remodeled and rebuilt of iron—in frumework no less than in armor. Tue iron bridge on the line of the Catasauqua and Foglesville Railroad is the lougest iron structure of the kind in the United States, the extreme length being 1,165 feet, and hight 90 feet. BeroneE 1829 it required about five pounds of coal to carry ono a milo. In that year Geo. Stephenson reduced it to 2.41 pounds of coke. It can now be brought to less than a qnarter of a pennd per tou per mile, Scientific Miscellany. The Source of Light in Flame. It has nntil recently been tanght tbat the light of tlames is altogether due to tho ignited particles of solid matter liberated in tho hurning gases. Recent experimeuts, bowever, havo proved that this is not true in all cases. In buraing hydrocarbons— whether a candle or hydrocarhon oils—the oxygen of the atmosphere first unites with the hydrogen, hy reason of its greater affinity for that gas than for carhon. If there is not an excess of oxygen present, the particles of carbon will be set free and pass off as smoke, or be deposited in tbe form of lamphlack. Tho uniou of the oxygen aud hydrogen is made without any material production of light or flame. The flame and light is duo to the burniug particles of solid carbon which vibrate, momentarily, with the evolution of waves of light, and are then consumed or converted into a invisiblo gas. If wehold 2 pieco of white crockery in a hydrocarbon flame, it is immediately blackened hy 2 deposit of carhon, which is cooled by the contact, and arrested in its progress of consumption. If we bold a piece of the same crockery in an oxyhydrogen flame it will not be blackened, for the reason that there is no carbon present. . When an electric light is projected upon a screen, it is distinctly noticeable that the brightness of the light is produced by the two ignited solid carbon points, while the space between them is almost dark—the little light that is visible is due to tbe passing oyer of fine particles of thecarhon from the positive to the negative pole, But’ all flames are not thus due to the ignition of particles of solid carbon or other solid matter. It has recently been shown that compression has much to do with the production of flame. Oxygen and hydrogen contain no solid matter, and hence it has been supposed that the flame prodnced hy their combustion could not be made to give out light. Recent experiments, however, haveshown that when these snbstances are ignited by an electric spark, ina very strong glass vessel, they give out a most intense light. This light is due to the compression produced by the expansion of the gases at the moment of ignition. The brightness of the electric spark may be largely increased by compression of the atmosphere throngh‘which it is passed. If we attach a glass tube to a force pump, and produce the clectric spark within it, while the density of the airis being constantly increased hy the action of the ‘pump, the luminosity of the spark will increase with the increasing density of the atmosphere in the tuhe, and fall off with the decrease of its density. Various other experiments of a similar nature have recently becn made to prove that the rule which influences the production of light inflames, without the presence of solid particles, is,—that the denser the products of comhustion, the greater is the light produced. Mrrtrorie Stonus have fallen in unusual quantities during the last six months. Birmingham,,in England, has recently been visited hy a shower of these celestial missiles, which fell in the streets of that city in great quantities during a very heavy rain storm. They were about the eighth of au inch in length, and greatly resembled the meteoric particles that fell in similar abundance on the 12th of June, 1853, Prof. Loomis says 8,000,000 stars shoot through the earth’s atmosphere evory tweuty-four honrs, some of them very small, weighing 480 to the ounce. GasEs From Voucanors.—In a report from the French Academy of Sciences, in 1858, is expressed an opinion that the gaseous emanations from a voleano, carefully . analyzed and compared, will throw light on the chemical process which gave them hirth; and enable ohservers in tho vicinity of a volcano, and through them the surroundiug population, to foresce the course which a coming eruption is likely to run, and of course serve as a useful warning. * 67 Tne Gotn-Bearino Rocks, —Sir Roderick Murchison, in the now edition of his “ Siluria,” has modified the views first pnt forth by him as to the distribution of gold in the earth’s crust. His most recent conclusions are: 1. That looking to the world at large, the auriferons veiustones in the lower silu“ie rocks contain the greatest quantity of gold. 2. That where certain igneous cruptions penetrated the sccondary deposits, the latter have been rendered anriferons for a limited distance only beyond tho jnuction of the two rocks, 3. That tho gencral axiom beforo insisted upon remains, that all secondary and tertiary deposits (except tle aurifcrons detritns in the latter) not so spocially affected never contains gold. 4, That as no unaltored, pnrely aqneous sediment ever contaius gold, tho argument in favor of the igneous origin of the metal is prodigiously strengtbened ; or iu other words, that tho granites and diorites have been the chief gold producers, and that the auriferous quartz-hands in the palseozoie rocks are also the result of heat and chemical agency. ProspHorescent Pooroorarus.—The Berlin Archiv for April gives the following method for making photographs which are invisible in the light, but are luminous in the dark: Sulphate of baryta (heavy spar) is finely pulverized, mixed with gum tragacanth and heated in a closed erncihle. Instead of heavy apar, a carbonate of haryta, strontia, or lime, with half its weight of sulphur, may be used. The pnlverized prodnet shonld he kept in a closed bottle. A sheet of alhumenized paper is moistened with wet blotting paper; when sticky the powdered substance is distrihuted equally over it hy a tuft of cotton and then dried in the dark. It is printed under a glass positive. Only a few seconds are required when baryta is used; with magnesia a little longer time is needed. In the dark, the light portions show the peculiar phosphorescent luminosity, the dark portions being distinguished by a want of phosphoresence. The picture will, however, slowly disappear. When required to keep, the picture is made on a film of paraffine poured on glass, and covered while still warm with the powder, and treated in the same manner as the alhumen paper, Countous APRLICATION oF Musican Notes. One of the most interesting uses to which it has been proposed to apply musical notes is that lately suggested by Mr. Airy, an English practitioner, who suggests that through their agency the strain exerted upon bridges and other girders may be very acenrately ascertained ; the notes given out by girders of the samelength and structure at any given tension heing identical, so that any difference in the notes will indicate a corresponding difference in the tension. The experiments of Mr. Airy were mado with a model of an ordinary how-string bridge; and Engineering suggests that the same process may be employed to advantage in the-construction’ of large and cowmplicated iron structures, and also for ascertaining the strains on the arched roofs of railway stations and the ties of suspension bridges. Interestinc ExPEnmvent wirn Hyproern.—M. Cailletet announces the extraordinary cireumstance that hydrogén will pass through iron evon at the common temperature on certain conditions. He caused two thin iron laminz to be welded together round the borders, so as to form a large artificial hlister. To this was welded a thin tube establishing a communication with the hollow space left between the two plates, and the whole apparatus so constructed was plunged into a bath of dilute sulphnric acid. The numerous bubbles which escaped throngh the open extremity of tlie tube being collected in a receiver, were ascertained to be hydrogeu. New Meruop or Preparing Macyusium. M. Reichert has devised a new method of preparing magnesium. He takes 1,000 grammes of the anhydrous double chloride of magnesium and potassium, pulverizes it, and mixes it with 100 grammes of finely powdered fluor spar; this mixture is fused with 100 grammes of sodium. The compound proposed for use occurs in the mineral kingdom iu tolerable abundance as carnalite, White pieces of this mineral are availablo, ond require no previous treatment; colored fragments must he dissolved in water, the impurities allowed to settle, and the lixivium evaporated.—Druggisis’ Circular

The Mining and scientific Press. Mechantcal, The Steam Engine to be Superseded. In the last edition of Mr. Bonrno's “Treatiso on the Steam Engine,” that eminent engineer expressed the conviction that **the steain engino would pass away hefore many years,”’ and somo other and more economical motor cone into use, in its . stead. Referenco was made to this fact in onr issne of Jnno 18th, 1868. ‘The cngineering world was somewbat startled by this annonneenient; not because its cnunciation was new; bnt heeanse of the high authority which then made tbe utterance. More recently, and withiu a fow weeks, Mr. Bourne has given to the world the first issne of another work, which is to be completed in twenty-four numbers, and wherein the anthor proposes to placo his readers in possession of all the important facts with regard to the progress of the steam ongine from the days of Watt to tho present time, to review the expedients which bave heen proposed as substitutes for the steam engine, and to analyze their respective degrees of merit and promise. The work will also contain practical and illnstrativo drawings anid descriptions of the best forms of air, gas and magnetic engines whieh have already been devised, with suitable commentaries and critical investigations thereof, with the object of deterring from tho adoption of the bad and doubtful, and leading toward the best types now availahle. In alluding to this enunciation, and to the first numher of Mr. Bourne's new work, which had then jnst appeared, the Engineer of Juno 12th, says: We have long hecn acqnainted with many of the views with which the present work will no donbt startle the engineering world, and evidences of this knowledge will bave been ohserved by the attentive reader of our pages to he occasionally cropping out, though we refrain from laying any connected statement of it hefore the pnblie. And if the engineers now awako to the perception of the great fact that the steam engine is slipping from their grasp—tbat it is a moribund expedient, now ahout to be superseded by other motors moro simple and less expensive—it will not he without an effort that they will have heen roused from their ancient somnolency, nor will it he without much intermediate scepticism that they will finally arrive at this salntary conviction: It is prohably to the anticipation of this phase of unbelief that we must attribute the references which Mr. Bourne bas giveu to his past counsels and predictions—under the idea no doubt that his authority would he thereby sniliciently fortified to lend fo necessary weight to his present expositions to ensure their fair and intelligent appreciatiou. Most persons who should venture to appear hefore theengineering public with the announcement that the steam engine was about to be done away with would be in danger of heing set down as ignorant enthusiasts, to whom no heed need be given; but such a conelnsion can bardly be arrived at when the intimation is made by a person already widely known for his intimate acqnaintance with the subject, and when, furthor, it is remembered that he is the author of most of the improvements which have heen introduced into the steam engine since Watt's time, although the real origin of these improvements lias not hitherto heen revealed, ss * ae _ The reflection presses itself upon us, as it will, no douht, do upon our readers, that such a work comin'g from snch a quarter indicatea the impending supersession of the steam engine as a prime mover, and muat be regarded os the beginning of the end. A revolution so enormous has not occurred in our day; and the puhlie curiosity will be intensely excited to learn what superior agent is likely to take the place of the ancient servant now ahout to disappear. An English engineer, now in New York, writes to tho London Exgineer as follows; “The cast iroh here astonishes me. I saw in Brooklyn Navy Yard a cast iron naval gun which had heen hit by a Southern shot about four feet from the muzzle, and the shot had left its mark, impressing the rifliug qnite clearly. There was nota crack upon the surface of the gun, hut the dint was driven right through the thickness of the gun and reproduced in the chase, so that a ae fitting shot could not he fired from it. Ueavy Macuine Toors.—Modern improvements largely require the prodnction of execedingly heavy work, combined with aecuracy of detail and finish. This demand calls, in turn, for machine tools of eomparative magnitudo and weight. Among the principal tools used in tho machino maunfacturing works of Wm. Sellers & Co., of Philadelphia, is a plauer, the capacity of which is, length 45 feet, width 10 feet, hisht 8 feet. ‘The same establishment has a radial drill with a 10-foot projecting swingarm, and a boring drill of 8-foot swing. These works have recently constructed a 24-foot vertical boring and tnrning machino for tho Charlestown Navy Yard, whose total weight is over 72 tons. This machino was inlly deserihed in our eolnmns of March 21st. A second tool of the samo dimensions, and to be constructed aftcr the same patterns, has been ordercd for tho Washington Navy Yard. New Mops or Orenatine Sue Vauves, Isaac Church, Jr., of Norwalk, Conn., has jnst patented au iniproyvemont in oporating tho slide valves of steam enginesand pwnps applicable more specially to direct douhleacting steam pumps, and it will snflice here to regard the same in sneb connection. The improvement is based upon that principlo of action, which has hefore been applied in various forms, in which the valve controlling tho action of the piston is shot or worked alternately in opposite directions by steam admitted throngh the agency of secondary valves that are opened and closed by the motion of the piston. But this invention differs from previous devices of the character referred to, in cansing the main valve to be thrown or shot by steam admitted through puppet valves so arranged as that the engine piston operates in a direct manner upon their stems to lift, and it may also to drop them, and wherehy not only are all outside connections for operating the valves dispensed with, but o most simple and efficient interior valve-operating action or arrangement secured. Harr Currine sy Macuinery.—Hair cutting by machinery is now an accomplished fact, so far as horsesand oxen are concerned, and it seems by no means impossible in the of the human head. M. Nabat has invented a mechanical razor, which, in principle, is something like a lawn-mower. A_ helix, with steel blades tangent toa comb, is made to rotate hy means of a flexihlo chain worked by a lever. One man works the lever, while the “operator” promenades the comb over the body of the animal, regulating the length of hair to be left. hy the inclination of thecomh. It is said that horses and other heasts enjoy being clipped by machinery. It, however, remains to be seen whether humanity will.—Mechanics’ Maga-. Zine, Mr. J. I’. Bennet annonnees that he can remove sulphur and phosphorus from pigiron, during its treatment in the Bessemer process, hy introdncing into the converting vessel carhonie acid gas, either before or with the air blast. He asserts that sulphurons and phosphoric acid are formed at the expense of the carhonic acid gas, the carbon of which is liberated. The gasis produced by acting on hrimstoue by hydrochloric acid, or by burning carbonaccous matter and storing in a gasometer. Suprrroriry oF Amentcan Cast Srerp. Experiments recently mado at the Navy Department, Washington, with cast stecl resulted in favor of an American hrand— that of tho Black Diamond Company, Pittsburg, Pa.—which atond the extraordinary test of 242,100 pounds tensile strength to the sqnare inch, being the highest on record, and showing a superiority over English mannfacturo. Mn. Farrparen in 1840, predicted that, in the course of four or five years, iron would entircly supersede wood in shipbuilding ; and he subsequently gave his opinion that the whole navy of Great Britain must be remodeled and rebuilt of iron—in frumework no less than in armor. Tue iron bridge on the line of the Catasauqua and Foglesville Railroad is the lougest iron structure of the kind in the United States, the extreme length being 1,165 feet, and hight 90 feet. BeroneE 1829 it required about five pounds of coal to carry ono a milo. In that year Geo. Stephenson reduced it to 2.41 pounds of coke. It can now be brought to less than a qnarter of a pennd per tou per mile, Scientific Miscellany. The Source of Light in Flame.

It has nntil recently been tanght tbat the light of tlames is altogether due to tho ignited particles of solid matter liberated in tho hurning gases. Recent experimeuts, bowever, havo proved that this is not true in all cases. In buraing hydrocarbons— whether a candle or hydrocarhon oils—the oxygen of the atmosphere first unites with the hydrogen, hy reason of its greater affinity for that gas than for carhon. If there is not an excess of oxygen present, the particles of carbon will be set free and pass off as smoke, or be deposited in tbe form of lamphlack. Tho uniou of the oxygen aud hydrogen is made without any material production of light or flame. The flame and light is duo to the burniug particles of solid carbon which vibrate, momentarily, with the evolution of waves of light, and are then consumed or converted into a invisiblo gas. If wehold 2 pieco of white crockery in a hydrocarbon flame, it is immediately blackened hy 2 deposit of carhon, which is cooled by the contact, and arrested in its progress of consumption. If we bold a piece of the same crockery in an oxyhydrogen flame it will not be blackened, for the reason that there is no carbon present. . When an electric light is projected upon a screen, it is distinctly noticeable that the brightness of the light is produced by the two ignited solid carbon points, while the space between them is almost dark—the little light that is visible is due to tbe passing oyer of fine particles of thecarhon from the positive to the negative pole, But’ all flames are not thus due to the ignition of particles of solid carbon or other solid matter. It has recently been shown that compression has much to do with the production of flame. Oxygen and hydrogen contain no solid matter, and hence it has been supposed that the flame prodnced hy their combustion could not be made to give out light. Recent experiments, however, haveshown that when these snbstances are ignited by an electric spark, ina very strong glass vessel, they give out a most intense light. This light is due to the compression produced by the expansion of the gases at the moment of ignition. The brightness of the electric spark may be largely increased by compression of the atmosphere throngh‘which it is passed. If we attach a glass tube to a force pump, and produce the clectric spark within it, while the density of the airis being constantly increased hy the action of the ‘pump, the luminosity of the spark will increase with the increasing density of the atmosphere in the tuhe, and fall off with the decrease of its density. Various other experiments of a similar nature have recently becn made to prove that the rule which influences the production of light inflames, without the presence of solid particles, is,—that the denser the products of comhustion, the greater is the light produced. Mrrtrorie Stonus have fallen in unusual quantities during the last six months. Birmingham,,in England, has recently been visited hy a shower of these celestial missiles, which fell in the streets of that city in great quantities during a very heavy rain storm. They were about the eighth of au inch in length, and greatly resembled the meteoric particles that fell in similar abundance on the 12th of June, 1853, Prof. Loomis says 8,000,000 stars shoot through the earth’s atmosphere evory tweuty-four honrs, some of them very small, weighing 480 to the ounce. GasEs From Voucanors.—In a report from the French Academy of Sciences, in 1858, is expressed an opinion that the gaseous emanations from a voleano, carefully . analyzed and compared, will throw light on the chemical process which gave them hirth; and enable ohservers in tho vicinity of a volcano, and through them the surroundiug population, to foresce the course which a coming eruption is likely to run, and of course serve as a useful warning. * 67 Tne Gotn-Bearino Rocks, —Sir Roderick Murchison, in the now edition of his “ Siluria,” has modified the views first pnt forth by him as to the distribution of gold in the earth’s crust. His most recent conclusions are: 1. That looking to the world at large, the auriferons veiustones in the lower silu“ie rocks contain the greatest quantity of gold. 2. That where certain igneous cruptions penetrated the sccondary deposits, the latter have been rendered anriferons for a limited distance only beyond tho jnuction of the two rocks, 3. That tho gencral axiom beforo insisted upon remains, that all secondary and tertiary deposits (except tle aurifcrons detritns in the latter) not so spocially affected never contains gold. 4, That as no unaltored, pnrely aqneous sediment ever contaius gold, tho argument in favor of the igneous origin of the metal is prodigiously strengtbened ; or iu other words, that tho granites and diorites have been the chief gold producers, and that the auriferous quartz-hands in the palseozoie rocks are also the result of heat and chemical agency. ProspHorescent Pooroorarus.—The Berlin Archiv for April gives the following method for making photographs which are invisible in the light, but are luminous in the dark: Sulphate of baryta (heavy spar) is finely pulverized, mixed with gum tragacanth and heated in a closed erncihle. Instead of heavy apar, a carbonate of haryta, strontia, or lime, with half its weight of sulphur, may be used. The pnlverized prodnet shonld he kept in a closed bottle. A sheet of alhumenized paper is moistened with wet blotting paper; when sticky the powdered substance is distrihuted equally over it hy a tuft of cotton and then dried in the dark. It is printed under a glass positive. Only a few seconds are required when baryta is used; with magnesia a little longer time is needed. In the dark, the light portions show the peculiar phosphorescent luminosity, the dark portions being distinguished by a want of phosphoresence. The picture will, however, slowly disappear. When required to keep, the picture is made on a film of paraffine poured on glass, and covered while still warm with the powder, and treated in the same manner as the alhumen paper, Countous APRLICATION oF Musican Notes. One of the most interesting uses to which it has been proposed to apply musical notes is that lately suggested by Mr. Airy, an English practitioner, who suggests that through their agency the strain exerted upon bridges and other girders may be very acenrately ascertained ; the notes given out by girders of the samelength and structure at any given tension heing identical, so that any difference in the notes will indicate a corresponding difference in the tension. The experiments of Mr. Airy were mado with a model of an ordinary how-string bridge; and Engineering suggests that the same process may be employed to advantage in the-construction’ of large and cowmplicated iron structures, and also for ascertaining the strains on the arched roofs of railway stations and the ties of suspension bridges. Interestinc ExPEnmvent wirn Hyproern.—M. Cailletet announces the extraordinary cireumstance that hydrogén will pass through iron evon at the common temperature on certain conditions. He caused two thin iron laminz to be welded together round the borders, so as to form a large artificial hlister. To this was welded a thin tube establishing a communication with the hollow space left between the two plates, and the whole apparatus so constructed was plunged into a bath of dilute sulphnric acid. The numerous bubbles which escaped throngh the open extremity of tlie tube being collected in a receiver, were ascertained to be hydrogeu. New Meruop or Preparing Macyusium. M. Reichert has devised a new method of preparing magnesium. He takes 1,000 grammes of the anhydrous double chloride of magnesium and potassium, pulverizes it, and mixes it with 100 grammes of finely powdered fluor spar; this mixture is fused with 100 grammes of sodium. The compound proposed for use occurs in the mineral kingdom iu tolerable abundance as carnalite, White pieces of this mineral are availablo, ond require no previous treatment; colored fragments must he dissolved in water, the impurities allowed to settle, and the lixivium evaporated.—Druggisis’ Circular