Volume 13 (1866) (424 pages)

The Hining and Scientific Press, 227 Alechanical. DANFORTH's STEAM GENERATOR. We have heard but little, of late, from this new principle of generating steam. ‘The American Artisan of August 29th, enya that one of these generators hos been working for over 0 yeur ot the works of (’. W. Neefus, 231 West street, New York. It oppears to he worked at a lower pressore thon wo hod supposed this euginc wos intended for—100 to 107 ibs. with tho temperature of the steam ot about 460°, or 133° saperheated. The performance, nccording to ono day’s operation, is reported os follows: ‘ lodiceted horsc-power, 8.5. Wuter, per hour, 180.8 tbs. Coal, per 12 hours, 600 Ihs—40 tbs. per hour. Water, per hour, per indicnted borse power, 21.3 ths. Conl, per boar indicated horse-power, 5.88 ths.” Farther observotions are to be mode, which we shall report o3 soon ns received. No especin! efforts have yet heen made to econowize fuel hy consuming emoke, gases, ete. The work is merely experimental, and the experiment has eo far been confined to simply showing that stcom can he sofely ond economically generated on this principle. Wheu that is fully done—and perfect confidence in the result is thus far munifested—economy in the use of juel so employed will he looked efter, with a proper class of cxperimente directed particularly to thot object. The experiments of Perkins, McCurdy and othere, forty years ogo, aod others still, in this country ot a later period, have already indicated thut a considerble advantage may ho goined from the odoption uf this mode of gencrating steam. ‘The question appears to he simply one of details, the €onclusion to which must he arrived at hy a lengthy and careful conrse of experiments. These experiments are now in progress, and, we presome, io efficient nod competent hands. We shall contiune to watch their development with interest, and report thereou whenever anything worthy of note transpires. Utirazixno Exnaust Stram.—Mons. P. Vabe has got up an engine with two pistons on one rod, on the principle of the ‘“ Wolfe” engine. Steam is distributed hy one volve. He claims that the exhaust steam in the large cylinder, whose area is double that of the small one, is as effective as it hag heen in the small onc when it was first nsed; that is, the effect ol the steam is douhled. ‘There are many expertents on this kind of engine, indicating thot the high pressure and low pressure engincs, with the aid of surface condensation, are likely to work together. This idea is, of course, founded upon the correctness of the theory of those who advocnte the plan of working eteam expansively. The American Artisan, in alIndiug to the ahove, saya: “We confess our faith in the utility of expansion, and helieve that when locomotive-boilers and engines are put on hoard ship, and exhaust into low pressure hoilers, there will he a great saving of fuel. Extraorpinary Rusvnts or SysteMaTizeD Lazox axyp Improve Macainery.—By the systematic arrangements of lnhor, and the great improvements in machiuery, recently introduced into the workshops of England, very superior “ Barlow ’' knives are now turned out ata cost of ahout five cents each ; while a very common knife is produced for about one and a half ccnts—less than two cénts for the hlade, hondle and manufacturer’s profit! Making full allowance for the sad commentary which this fact presents with regard to the miserably low equivalent which Englieh operatives receive for their lahor, it, nevertheless, affords a most striking evidence of the vast henefits derivable . from modern machinery, and the admirahle systematization of lahor which ie now introduced into all large mannfacturing estahlish. ments. Rust on Inon—Paint.—Every particle of Tost on irou may he removed hy first softening it with petroleum and then rubhiug well with Coarse sand-paper. ‘lo paint iron, take lymphlack sufficient for two coats, and mix Pith /equal quantities of Japan varnish and hoiled Noseed oil. © Coat Currixo By Macutxery.—A coal ent“ting machine is in operation in a coal mine neor Leeds, England, that will eut a length of forty feet per hour, and which is so simple in construction and operation, that any ordinary niiner ean work it, ond with but little of the risk to which he is ordinarily exposed. It ia said to do the work of tweuty men, at on expenditoro of thirty gallons of woter per minnte, working ut a pressure of 300 pounds per inch. Tt works on rails laid along the drift, so thot it is easily moved and operated hy one mon. The cost of coal got by hand, ot the mine, is ahout seveuteen cents per ton; the cost with this mochino is from six to ten cents. A model of this machine wos shown and explained ot a late meeting of the Institute of Civil Kogineers, whero it attracted much aottention, os reported in Chamher’s’ Journal, Why cannot cool cutting niochines he economicolly introduced inte the conl mines of the Pueifie coast, where lobor is so much higher than itis in the Kuropeoo mines ? Tue Tiast Rottixo Mitt was invented and put in operation io 1785. ‘Tho moderu method of manufacturing iron was introduced at that time; at which period the price was from $85 to $95 per ton. The great reduction in the cost of this universol commodity, aud which hos heen gradually made frow the figure nomed, to its present price, has heen in consequence of further improvements which hove been from time to time introduced into the various processes of its maoufacture. Lacqueas are used npon polished metals and wood, to impart the oppearance of gold. As they are waoted of different depthe and shades of colors, it is hest to keep a concentrated solution of each coloring ingredient ready so that it may at anytime he added to produce any desired tint. We append several receipts for making different kinds of lacquers : 1. Deep Golden-colored Lacquer.—Seed lac, three ounces; turmeric, one ounce; dragotl’s htood, a qnarter of an ounce ; alcohol, one pint. Digest for a week, frequently ebaking. Decuot and filter. 2. Gold-colored Lacquer.—Ground turmeric, one pound; gamboge, an ounce and a half; gum-sandarach, three pounds and a half; shell lac, three-quarters of a pound (oll in powder) ; rectified spirits of wiuc, two gallons. Dissolve, strain, and add one pint of turpentine varnish. 3. Red-colored Lacquer.—Spanish anatto, three pounds; drogon’s blood, one pound ; gum-sandarach, three ponnds and a,quarter; rectified spirits, two gallons; turpentine varnish, one quart. Dissolve and mix os the Inst. 4. Pale Brass-colored Lacquer—Gamhoge, cut small, one ounce; cape aloes, ditto, three ounces; pale shell lac, one pound; rectified sprits, two gallons. Dissolve aod mix as No.2. 5. Seed lac, dragon’s hlood, anatto, and gambhoge, of each a quarter of a pound ; saffrou, one ounce ; rectified spirits of wine, ten pints. Dissolved and mix as No. 2, torms'a very excellent lacquer. Lacquer ssould always stand till it is quite fine before heing used. Tne London Pneumatic Dispatch, hy which small parcels are trangported from one purt of the city to the other, hy means of the exhaustion of air from a tnhe, is familiar to our readers. It appears from a report reccotly made hy the directors of thie compony, that 120 tons of goods can he transmitted through the tuhe every hour, nt a speed of eighteen miles an hour, and that the cost is less than oné penny (two cents) per ton for cach mile. ‘They anticipate large dividends from the line when completed to points outside the city. . Tue Revontino Snip Tuxory is to he reduced to practice. It will he remembered that the invention consists of a ship so constructed as to roll over the surface of the water instead of heing forced ¢hrough it. A company hos been formed in Baltimore to test its feasibility. Bronztno.—he following is a good method of hronzing tin castings: When clean, wash thém with a mixture of one part each of sulphate of copper and sulphate of iron io twenty parts‘of water; dry and‘wash ngain with distilled vinegar eleven parts. When dry, polish with coleothar.' Coat ot isa hetter substance for preserving potassium and sodium than naphtha. In coal oil sodium keeps its luster for mouths, while in the purest uaphtha it is dimmed in a few days. Scientific Wiscetlany. THE EFFEOT OF SUNSHINE ON OOMBUSTION. It hos long heeo a popalor notion thot snnshine deadens fire. This idea hos atso been very geuerally entertained by scientific men as well. Dr. Brewer, of ‘Trinity Hull. College, Comhridge, Engluod, in his * Ilandhook of Science,” in spenking of tho effeet of sunshine opor combustion, hy the rarefaetior of the otmospliere, odds: ‘Sunshine produces also some chemical effect upon the air or fuel, detrioentol to combustion.” This paragraph hes also been retained in the Americen edition of this work, revised nod edited hy R. E. Petersou, member of the Acodemy of Naturol Sciences, Phtludelphia. ‘The first recorded experinients made henring upon this subject were conducted by Ur. McReever, in 1824. His experiments led him to the conclusion thot the popular impression woe susteined. He found that e candle would hurn awoy more rapidly in a painted lantern, thon iu one not peinted—~hoth exposed to the direct roys of the sun. Ie found that it required eleven minutes to burn io the sunshine the eame weight of candle that hurned io ten minutes in the dark lantero expoeed to the same sunshioe. Some other experimenters, however, differed with McReever. ‘ In 1856, however, the matter wes tokon up more eloborately hy Prof. Joseph Le Conte, of Columbia, S. C. He arranged a dark room in.which he lighted two candles of identical meke. Upon the flame only, of one, hy the eid of a reflector and burning glase, he concentrated the rays of the sun; the other was suffered to huru without any contnct with the sun's rays. ‘The result showed’ that the effect of the sun’s rays, though greatly exaggerated hy concentration, did not appreciahly affect the consninption of the candle. At the late meeting of the American Scientific Association at Buffalo, Prof. Horsetord, of Cambridge, read a very interesting paper upon this subject, in which he alluded to eomg experiments and ohservations of his own, going to suhstantiate the conclusions of Professor Le Conte, that the sun’s rays do not exert any chemical effect on the procese of combustion. He explained the apparent effect of Doctor McReever’s lantern experiment hy the well known power which dark colore have of absorbing radiant heat and convertiog it into heat of conduction ; hy which the air in the painted lantern was more heated than the air in the unpainted, wherehy the tallow of the candle was warnied toward the process of liquefaction, and the heat of the flame to that extent spared for combustion. Yhe fact that fires in gratcs and stoves, which hurn hriskly in the fore part of the day, slacken during the hours of a warm summer’s noon, has long been explained as arising from the mechanical, rather than from the chemical . effects, of the sun’s rays—the rarefaction of the atmosphere, in consequence of which less oxygen is brought into contact with the comhustible hody which is heing consumed. A Ay fire always burns more freely in a cold, frosty, wioter’s day than in a warm, thawing day, for the double reasou that in the latter case there is less oxygen iua given quautity of air, and more moisture. For the same reason we find the great difference in the draught of our stoves ohserved iu this city, between still foggy days and those accompanied by the brisk, dry wiuds of our summer months. Iron founders are not unfrequently greatly troubled to make their furnaces work properly in the middey sun of a very warm day. Housewives have often found that stove ovens, which hake well in the morning and afternoon, cannot he made to perform that service at all in the hrightness of the noouday euo. A rarefied atmosphere, often rendered still more non-conductive to combustion hy an excess of moisture, is the cause of the trouble. From the above, it will he ohserved that the popular idea that sunshine exerts a chemical effect upon the process of combustion, is without foundation, in fuct ; hut that the heat of the sun does exert a mcchanical effect upon the atmosphere, which deprives combustion of such an amonntof oxygeuas to produce a very noticable detrimental interference with that process.Scientiric axp Mecuanican Resgarcn. The world once lasghed nt Oeretedt’s electrical experiments, thinkinz that his little mognets, voltnie pile, hits of copper wire, ete., eould never lend to any practicnl result; yet, from these little trinkets came the wonderworking discovery of the electric telegraph. When Prof. Black, of Mdiohurg, during his investigations into the ahstraet natare of caloric. ninde his diseovery uf letent heat, not even he, himself, thought it would ever lead to anything of special value; yet it wos that very discovery that opened the wey for Watt to moke his importont improvement in the steom engine. To sny nothing of the grent discovery of phutography, end other importaut developments which have growo ont of investigntions with regord to light; perhope the most valuable and promising of oll the scientific generolizations of the last two or three decades, ere those reloting to the Conservation of Force—to heat, light, electricity, magoctism, golvonism, etc., nod the convertibility of the one into the other. This class of investigatione is still in its infancy, and we can as yet ece hut the hright glimmerings of mognificent results which philosophers confidently nnticipote at an early future—resulte which hid fair to work not only revolutions in the great motive power—steam ; hut also in the very meane employed for producing hoth it and the light hy which we are enahled to continue our avocations after the light of dey hos declined. People sometimes think that the rapid progress in discovery and inventions of the last century, must produce a deorth in that direction during the coming century. Notso; the discoveriee up to the present time, are hut the preliminaries which are to eerve as hints to gnide the philosopher and inventor in the developments of greater wondcrs than have yet heen dreamed of hy the most profonnd of the world’s philosophere. Each new discovery helps to others. ‘Whenever a pew truth hccomes apparent, its ramifications appear inexhaustihle. As we continue to explore it, its applications multiply upon every hand, till they seem illimitable. Indeed, if the inventor or the ecientific inquirer had hut one original principle to work from, hénever could exhaust it; for it would he found interlinked with the entire Universe. Tae Conpuctive Power or Mercury For Hear.—There are peculiar difficulties iu the way of ascertaining accurately the conducting power of mercury for heat; hat Professor. Gripon, of Lille, seems to have overcome them very successfully, and to have made a determination which may he regarded as very closely approximating to nhsolute accnracy. It shows the conductivity of mercury for heat to he 407-1,000ths of that of lead. Experiments made after Peclets’s method shows that if the conducting power of silver is 100, that of mercury is 3.54. Mercury etands, therefore> the last of the metals, and a little hefore marhle and gas coke. It should be ohserved, however, that the conducting power of this metal for heat and for electricity are very different, the former heing 3.54, the latter 1.80. Cracks in Fourmitore may he advantageously filled hy the following composition : Moisten a piece of recently burned time with enough water to make it fall into powder; mix one part of thie slaeked lime with two parts of rye flour, and a sufficient quautity of hoiled linseed oil to form it into a thick, plastic mags. 5 A sew test for acids and alkalies. called “eyanin,” has heen discovered hy a German chemist. It is an artificial blue, obtained by acting on chinoline with iodide of amyle. Its delicacy as a test for acids and hases ie quite morvelous, aod far superior to litmus. E Common phosphorous hears. for twenty or thirty eeconds without ignition, the action of a radiant heat at a focus where, in the fraction of a secoud, platinized platinum is raised to a white heat. Tr is said that sands which are nsed esa filter for the purification of water are only effective when they contain the black oxyd of iron or magnetic carhide, a

The Hining and Scientific Press, 227 Alechanical. DANFORTH's STEAM GENERATOR. We have heard but little, of late, from this new principle of generating steam. ‘The American Artisan of August 29th, enya that one of these generators hos been working for over 0 yeur ot the works of (’. W. Neefus, 231 West street, New York. It oppears to he worked at a lower pressore thon wo hod supposed this euginc wos intended for—100 to 107 ibs. with tho temperature of the steam ot about 460°, or 133° saperheated. The performance, nccording to ono day’s operation, is reported os follows: ‘ lodiceted horsc-power, 8.5. Wuter, per hour, 180.8 tbs. Coal, per 12 hours, 600 Ihs—40 tbs. per hour. Water, per hour, per indicnted borse power, 21.3 ths. Conl, per boar indicated horse-power, 5.88 ths.” Farther observotions are to be mode, which we shall report o3 soon ns received. No especin! efforts have yet heen made to econowize fuel hy consuming emoke, gases, ete. The work is merely experimental, and the experiment has eo far been confined to simply showing that stcom can he sofely ond economically generated on this principle. Wheu that is fully done—and perfect confidence in the result is thus far munifested—economy in the use of juel so employed will he looked efter, with a proper class of cxperimente directed particularly to thot object. The experiments of Perkins, McCurdy and othere, forty years ogo, aod others still, in this country ot a later period, have already indicated thut a considerble advantage may ho goined from the odoption uf this mode of gencrating steam. ‘The question appears to he simply one of details, the €onclusion to which must he arrived at hy a lengthy and careful conrse of experiments. These experiments are now in progress, and, we presome, io efficient nod competent hands. We shall contiune to watch their development with interest, and report thereou whenever anything worthy of note transpires. Utirazixno Exnaust Stram.—Mons. P. Vabe has got up an engine with two pistons on one rod, on the principle of the ‘“ Wolfe” engine. Steam is distributed hy one volve. He claims that the exhaust steam in the large cylinder, whose area is double that of the small one, is as effective as it hag heen in the small onc when it was first nsed; that is, the effect ol the steam is douhled. ‘There are many expertents on this kind of engine, indicating thot the high pressure and low pressure engincs, with the aid of surface condensation, are likely to work together. This idea is, of course, founded upon the correctness of the theory of those who advocnte the plan of working eteam expansively. The American Artisan, in alIndiug to the ahove, saya: “We confess our faith in the utility of expansion, and helieve that when locomotive-boilers and engines are put on hoard ship, and exhaust into low pressure hoilers, there will he a great saving of fuel. Extraorpinary Rusvnts or SysteMaTizeD Lazox axyp Improve Macainery.—By the systematic arrangements of lnhor, and the great improvements in machiuery, recently introduced into the workshops of England, very superior “ Barlow ’' knives are now turned out ata cost of ahout five cents each ; while a very common knife is produced for about one and a half ccnts—less than two cénts for the hlade, hondle and manufacturer’s profit! Making full allowance for the sad commentary which this fact presents with regard to the miserably low equivalent which Englieh operatives receive for their lahor, it, nevertheless, affords a most striking evidence of the vast henefits derivable . from modern machinery, and the admirahle systematization of lahor which ie now introduced into all large mannfacturing estahlish. ments. Rust on Inon—Paint.—Every particle of Tost on irou may he removed hy first softening it with petroleum and then rubhiug well with Coarse sand-paper. ‘lo paint iron, take lymphlack sufficient for two coats, and mix Pith /equal quantities of Japan varnish and hoiled Noseed oil. © Coat Currixo By Macutxery.—A coal ent“ting machine is in operation in a coal mine neor Leeds, England, that will eut a length of forty feet per hour, and which is so simple in construction and operation, that any ordinary niiner ean work it, ond with but little of the risk to which he is ordinarily exposed. It ia said to do the work of tweuty men, at on expenditoro of thirty gallons of woter per minnte, working ut a pressure of 300 pounds per inch. Tt works on rails laid along the drift, so thot it is easily moved and operated hy one mon. The cost of coal got by hand, ot the mine, is ahout seveuteen cents per ton; the cost with this mochino is from six to ten cents. A model of this machine wos shown and explained ot a late meeting of the Institute of Civil Kogineers, whero it attracted much aottention, os reported in Chamher’s’ Journal, Why cannot cool cutting niochines he economicolly introduced inte the conl mines of the Pueifie coast, where lobor is so much higher than itis in the Kuropeoo mines ? Tue Tiast Rottixo Mitt was invented and put in operation io 1785. ‘Tho moderu method of manufacturing iron was introduced at that time; at which period the price was from $85 to $95 per ton. The great reduction in the cost of this universol commodity, aud which hos heen gradually made frow the figure nomed, to its present price, has heen in consequence of further improvements which hove been from time to time introduced into the various processes of its maoufacture. Lacqueas are used npon polished metals and wood, to impart the oppearance of gold. As they are waoted of different depthe and shades of colors, it is hest to keep a concentrated solution of each coloring ingredient ready so that it may at anytime he added to produce any desired tint. We append several receipts for making different kinds of lacquers : 1. Deep Golden-colored Lacquer.—Seed lac, three ounces; turmeric, one ounce; dragotl’s htood, a qnarter of an ounce ; alcohol, one pint. Digest for a week, frequently ebaking. Decuot and filter. 2. Gold-colored Lacquer.—Ground turmeric, one pound; gamboge, an ounce and a half; gum-sandarach, three pounds and a half; shell lac, three-quarters of a pound (oll in powder) ; rectified spirits of wiuc, two gallons. Dissolve, strain, and add one pint of turpentine varnish. 3. Red-colored Lacquer.—Spanish anatto, three pounds; drogon’s blood, one pound ; gum-sandarach, three ponnds and a,quarter; rectified spirits, two gallons; turpentine varnish, one quart. Dissolve and mix os the Inst. 4. Pale Brass-colored Lacquer—Gamhoge, cut small, one ounce; cape aloes, ditto, three ounces; pale shell lac, one pound; rectified sprits, two gallons. Dissolve aod mix as No.2. 5. Seed lac, dragon’s hlood, anatto, and gambhoge, of each a quarter of a pound ; saffrou, one ounce ; rectified spirits of wine, ten pints. Dissolved and mix as No. 2, torms'a very excellent lacquer. Lacquer ssould always stand till it is quite fine before heing used. Tne London Pneumatic Dispatch, hy which small parcels are trangported from one purt of the city to the other, hy means of the exhaustion of air from a tnhe, is familiar to our readers. It appears from a report reccotly made hy the directors of thie compony, that 120 tons of goods can he transmitted through the tuhe every hour, nt a speed of eighteen miles an hour, and that the cost is less than oné penny (two cents) per ton for cach mile. ‘They anticipate large dividends from the line when completed to points outside the city. . Tue Revontino Snip Tuxory is to he reduced to practice. It will he remembered that the invention consists of a ship so constructed as to roll over the surface of the water instead of heing forced ¢hrough it. A company hos been formed in Baltimore to test its feasibility. Bronztno.—he following is a good method of hronzing tin castings: When clean, wash thém with a mixture of one part each of sulphate of copper and sulphate of iron io twenty parts‘of water; dry and‘wash ngain with distilled vinegar eleven parts. When dry, polish with coleothar.' Coat ot isa hetter substance for preserving potassium and sodium than naphtha. In coal

oil sodium keeps its luster for mouths, while in the purest uaphtha it is dimmed in a few days. Scientific Wiscetlany. THE EFFEOT OF SUNSHINE ON OOMBUSTION. It hos long heeo a popalor notion thot snnshine deadens fire. This idea hos atso been very geuerally entertained by scientific men as well. Dr. Brewer, of ‘Trinity Hull. College, Comhridge, Engluod, in his * Ilandhook of Science,” in spenking of tho effeet of sunshine opor combustion, hy the rarefaetior of the otmospliere, odds: ‘Sunshine produces also some chemical effect upon the air or fuel, detrioentol to combustion.” This paragraph hes also been retained in the Americen edition of this work, revised nod edited hy R. E. Petersou, member of the Acodemy of Naturol Sciences, Phtludelphia. ‘The first recorded experinients made henring upon this subject were conducted by Ur. McReever, in 1824. His experiments led him to the conclusion thot the popular impression woe susteined. He found that e candle would hurn awoy more rapidly in a painted lantern, thon iu one not peinted—~hoth exposed to the direct roys of the sun. Ie found that it required eleven minutes to burn io the sunshine the eame weight of candle that hurned io ten minutes in the dark lantero expoeed to the same sunshioe. Some other experimenters, however, differed with McReever. ‘ In 1856, however, the matter wes tokon up more eloborately hy Prof. Joseph Le Conte, of Columbia, S. C. He arranged a dark room in.which he lighted two candles of identical meke. Upon the flame only, of one, hy the eid of a reflector and burning glase, he concentrated the rays of the sun; the other was suffered to huru without any contnct with the sun's rays. ‘The result showed’ that the effect of the sun’s rays, though greatly exaggerated hy concentration, did not appreciahly affect the consninption of the candle. At the late meeting of the American Scientific Association at Buffalo, Prof. Horsetord, of Cambridge, read a very interesting paper upon this subject, in which he alluded to eomg experiments and ohservations of his own, going to suhstantiate the conclusions of Professor Le Conte, that the sun’s rays do not exert any chemical effect on the procese of combustion. He explained the apparent effect of Doctor McReever’s lantern experiment hy the well known power which dark colore have of absorbing radiant heat and convertiog it into heat of conduction ; hy which the air in the painted lantern was more heated than the air in the unpainted, wherehy the tallow of the candle was warnied toward the process of liquefaction, and the heat of the flame to that extent spared for combustion. Yhe fact that fires in gratcs and stoves, which hurn hriskly in the fore part of the day, slacken during the hours of a warm summer’s noon, has long been explained as arising from the mechanical, rather than from the chemical . effects, of the sun’s rays—the rarefaction of the atmosphere, in consequence of which less oxygen is brought into contact with the comhustible hody which is heing consumed. A Ay fire always burns more freely in a cold, frosty, wioter’s day than in a warm, thawing day, for the double reasou that in the latter case there is less oxygen iua given quautity of air, and more moisture. For the same reason we find the great difference in the draught of our stoves ohserved iu this city, between still foggy days and those accompanied by the brisk, dry wiuds of our summer months. Iron founders are not unfrequently greatly troubled to make their furnaces work properly in the middey sun of a very warm day. Housewives have often found that stove ovens, which hake well in the morning and afternoon, cannot he made to perform that service at all in the hrightness of the noouday euo. A rarefied atmosphere, often rendered still more non-conductive to combustion hy an excess of moisture, is the cause of the trouble. From the above, it will he ohserved that the popular idea that sunshine exerts a chemical effect upon the process of combustion, is without foundation, in fuct ; hut that the heat of the sun does exert a mcchanical effect upon the atmosphere, which deprives combustion of such an amonntof oxygeuas to produce a very noticable detrimental interference with that process.Scientiric axp Mecuanican Resgarcn. The world once lasghed nt Oeretedt’s electrical experiments, thinkinz that his little mognets, voltnie pile, hits of copper wire, ete., eould never lend to any practicnl result; yet, from these little trinkets came the wonderworking discovery of the electric telegraph. When Prof. Black, of Mdiohurg, during his investigations into the ahstraet natare of caloric. ninde his diseovery uf letent heat, not even he, himself, thought it would ever lead to anything of special value; yet it wos that very discovery that opened the wey for Watt to moke his importont improvement in the steom engine. To sny nothing of the grent discovery of phutography, end other importaut developments which have growo ont of investigntions with regord to light; perhope the most valuable and promising of oll the scientific generolizations of the last two or three decades, ere those reloting to the Conservation of Force—to heat, light, electricity, magoctism, golvonism, etc., nod the convertibility of the one into the other. This class of investigatione is still in its infancy, and we can as yet ece hut the hright glimmerings of mognificent results which philosophers confidently nnticipote at an early future—resulte which hid fair to work not only revolutions in the great motive power—steam ; hut also in the very meane employed for producing hoth it and the light hy which we are enahled to continue our avocations after the light of dey hos declined. People sometimes think that the rapid progress in discovery and inventions of the last century, must produce a deorth in that direction during the coming century. Notso; the discoveriee up to the present time, are hut the preliminaries which are to eerve as hints to gnide the philosopher and inventor in the developments of greater wondcrs than have yet heen dreamed of hy the most profonnd of the world’s philosophere. Each new discovery helps to others. ‘Whenever a pew truth hccomes apparent, its ramifications appear inexhaustihle. As we continue to explore it, its applications multiply upon every hand, till they seem illimitable. Indeed, if the inventor or the ecientific inquirer had hut one original principle to work from, hénever could exhaust it; for it would he found interlinked with the entire Universe. Tae Conpuctive Power or Mercury For Hear.—There are peculiar difficulties iu the way of ascertaining accurately the conducting power of mercury for heat; hat Professor. Gripon, of Lille, seems to have overcome them very successfully, and to have made a determination which may he regarded as very closely approximating to nhsolute accnracy. It shows the conductivity of mercury for heat to he 407-1,000ths of that of lead. Experiments made after Peclets’s method shows that if the conducting power of silver is 100, that of mercury is 3.54. Mercury etands, therefore> the last of the metals, and a little hefore marhle and gas coke. It should be ohserved, however, that the conducting power of this metal for heat and for electricity are very different, the former heing 3.54, the latter 1.80. Cracks in Fourmitore may he advantageously filled hy the following composition : Moisten a piece of recently burned time with enough water to make it fall into powder; mix one part of thie slaeked lime with two parts of rye flour, and a sufficient quautity of hoiled linseed oil to form it into a thick, plastic mags. 5 A sew test for acids and alkalies. called “eyanin,” has heen discovered hy a German chemist. It is an artificial blue, obtained by acting on chinoline with iodide of amyle. Its delicacy as a test for acids and hases ie quite morvelous, aod far superior to litmus. E Common phosphorous hears. for twenty or thirty eeconds without ignition, the action of a radiant heat at a focus where, in the fraction of a secoud, platinized platinum is raised to a white heat. Tr is said that sands which are nsed esa filter for the purification of water are only effective when they contain the black oxyd of iron or magnetic carhide, a