Volume 20 (1870) (454 pages)

SCIENTIFIG “PRESS. [January 1, 1870. CONURURICALIONS. Dressing of Ores—A Freiberg Process. [Written for the Scientific Press.] The subject of dressing ores has received too little attention iu our country. Miners geuerally have worked only for the day, not intending to spend many years in tho business, aud trying to get out as much precious motal as possible iu a shori time, even ata great waste. This way of working answers perhaps for the early days of mining; hut a more ecarefnl and precise method must finally be adopted; and the sooner this is done, the hetter for the country. Many mines which cannot now bo worked at a profit might still he very lucrative if they had been properly worked at first. For mining improvements we naturally look to older couutries, where mining has long been a business. All our most valuahle hints have thus far come from other lands. The American really originates hut few theories or principles; hut he has a wonderful power of adaptiug, and making practical, old ideas, which, perhaps, have never before been successfully carried out. It is with the idea of saying something, from which useful hints may be extracted, that it is proposed to give one or two examples of the way ores are treated in Frei. berg. Of course no whole process can he bodily imported from a country where labor is as cheap as it isin Germany. Still it is thought that many of your readers who canuot goto Hurope will be glad to hear through yonr columns of what is really being done in tho old world, there being no English work extant which gives the details of the processes used. . Kiistel’s hook comes the uearest to this.—Ep. . The Chur Prinz Mine, Near Freiberg, will be taken as a good example—this mine bolonging to the government, and being worked for the purpose of promoting mining iuterests in general, rather than of hringing in a special revenue. Itis situated about five miles from Freiherg, close to the Mulde river; and in its general characteristics is nearer, perhaps, to the mines of Austin than to any others on the coast, The ore is principally argentiferous galena (with some gray copper ore containing silver), which occurs with iron pyrites, quartz, fluorspar and heavy spar. The country rock is gneiss, It is to be understood that the ore would be cousidered worthless here, not heing rich enough to be worked; but it must not be forgotten that the price of labor, on the other hand, is also very low. Scparation in the Mine. In the mine the ore is separated into three classes, and these are hoisted out sepatately. They are: Class A, “‘ separation ore;” class B, stamp mill ore; class C, harren rock, Af preseut, only the first elass will be spoken of, as class B undergoes a distinct treatment, aud the following remarks apply to this class (A) only. Reduction to a Proper Size and Sorting. The ore is first crushed in an ore-breakor modeled after Blake’s patent. The jaws of the machine play to and fro 213 times per minute, and are about 1'4 inches apart. The oro is thus brokeu up into pieces which range up to 1% eubic inches in size. These pieces aro brokeu up fiuer, to % cubic inches, in a second ore-crusher which plays 256 times per minute, and whose jaws are 34 inch apart. Itis thought that by crushing first more coarsely and then more finely, considerable is gained in an economical point of view. The crushed ore now falls into a set of four sieves, or swinging riddles, and is sorted into five classes. The sieves have a length of 834, 8, 64 and 4% feet, aud meshes 5-16, 3-16, 2-16 and 1-16 inches wide respectively. The swing is six inches, The finest dust is washed in a hand buddle, whichis 12 feet long, 30 iuches wide, and 22 inches deep; the rest go to the jigging machines, except that which will not pass through the coarsest sicve. This is carried by an elevator—consisting of huckets attached to an endless hand—to a rolling mill. This consists of two cast iron rollers, 9 inches wide aud 14 inches high, which require about two horse-power to drive them at tlic rate of 39 revolutious por minute. The ore falls through into a cylindrical trommel or drum, which revolves 18 times per minute and sorts into 5 different classes, the sieves having meshes respectively +4, 3-16, 44 and 1-16 inch wide. The finest product is washed in the hand buddle; the others are jigged. These special details are given hecause a proper sizing of the grains is all important for the foliowing processes, and too much stress cannot be laid on this point. Conld the grains be ohtained of exactly the same size, an almost perfect soparation would follow. It is not to be expected that we can work so thoroughly iu this country, where labor isso high; but still many will see how these and other processes may be shortened and eheapened to suit our circumstances, and yet do valuable work. Up to this point almost no manual labor is required, except in overseeing the working of the machines, Several workmen areemployed at the mine spoken of, but their numbers could easily be reduced to two or three. The Jigging Machines. The ore has now been sorted into four elasses, according to the size of the grains. These are carried to four different sets of jigging machines. The sieves of the first four machines have 16 meshes per sqnare inch; the second, 25 meshes; the third, 36 meshes; the fourth, 64 meshes. The stroke is ahout seven inches. All 16 machines use eight cuhie feet of water per minute. But only balf are at work at one time, as while one is working, the other is being cleaned out hy the hoy who has charge of a set of two, It takes three and a half to four minutes to treat each charge. In this country we would hardly be contented with thege machines. The jigging gives as products: Ist. Barren ore. 2d. Small graius, in which are still particles of ore mixed with rock, and which must be stamped finer with other stamp mill ore (to he described hereafter). 3d. Galena ore, which is pure euough to be sold. This contains 75 per cent. lead and about 0.05 per cent. silver, or about $19 to the ton. To drive all the machinery described, there isa 12-horse power steam engine, with 1414-ineh eylinderand 2% feet stroke, [fO BE CONTINUED.] dar ix Gas.—Professor Silliman and Wurtz have heen investigating the effects of atmospheric air upon the illumiuating power of gas, with, according to the Chemical News, the following results: ‘‘For any quantity of air less than five per cent., mised with gas, the loss in caudle power due to the addition of each one per cent., isa little over six-tenths of a candle (0'611 exactly); above that quantity the ratio of loss falls to half candle power for each additional one per cent. up to about twelve per cent. of air; above which, up to five per cent., the loss iu illuminating power is nearly four-tenths of a candle for each one per cent. of air added to the gas. With less than one-fourth of atmospheric air, not quite fifteen per cent. of the total illuminating power romains, and with between thirty and forty per cent., it totally disappears.” Tue Cours Purtosopny.—‘‘Iu the theory of positivism there is no room for metaphysics, nothing for tho metaphysician to do. Positivism has to do not simply with the facts of scicnce, the phenomena, but it aspires to be a general philosophy which shall express in a single formnla a uuiversal truth respecting all phenomena, It says you cannot know the absolute, the infinite; bnt you ean, by searching, find out the general law. It here sets its limit to speculation, and rules out the metaphysical and the supernatural; or, if it is goiug to fartosay that, it holds a position of indifforentism toward the supernatural. It bnilds its universal philosophy, if not wholly upon the material, yet upon a necessary union of thought and matter. It admits no fact outside of experience,”— Courant, — Deep-Sea Sounding and Dredging. [Reported expressly for the Scientific Press. . The regular monthly meeting of the New York Society of Practical Engineering was held at the Cooper Institute, N. Y., on ‘Wednesday evening, December 8th, President James A. Whitney in the chair. The suhject of ‘‘Deep-Sea Sounding and Dredging” was discussed in an elaborate paper, by Prof. William Mohiuson, of Brooklyn. In his opening, the writer alluded to the vapid advancemcut of science within a few. years, and the mutual dependence of the physical sciences, Mavine geology has reeeived a new and important impulse since the laying of telegraph cables made it necessary to sound and dredge the ocean. But science has done comparatively little, as yet, by its researches in the ocean depths. As sounding and dredging, however, are an ahsolute necessity for the advancement of marine science and as a preparation for laying cables, it isof the greatest importance that the most perfect sounding devices should be invented. None heretofore used have been free from objection. The earliest sounder used was the common lead and line. It answers for shallow water, but is not reliahle beyond a depth of three or four hundred fathoms. In 1818, Sir John Ross procured shells, shrimps and other crustaceans from the hottom of Baffln’s Bay, in water more than 650 fathoms deep. In 1830, Vidal carried dredging successfully to a depth of 200 fathoms, and in 1841, Admiral Sir J. C. Ross procured a variety of invertehrate marine animals from the bottom of the Antaretie Ocean at a depth of 270 fathoms. But all the old souuders were crude, and could not be used successfully in very deep water, America has been the pioneer in deepsea sounding, and it was not until 1858 that the secrets of the deep ocean bed wererevealed. In that year, Midshipman Mitchell, on board the U. 8. hrig Dolphin, hrought up ooze composed of the remains of microscopie animals, from the bottom of the Atlantic, where the water was 1,700 fathoms, or about two miles deep. Devices for Deep Sounding. The device heretofore most extensively used in the United States, and, with some modifications, also in the British Navy, for deep sounding, is an iuvention of Lieut. Brookes, of the U. 8. Navy. It consists of arod, to the upper end of whichis attached a hoavy ball, hollowed out to receive it, the lower end of the rod being provided witha eup containing a valve. When the instrument strikes the bottom, the hall falls off, the cup fills with the ooze of the bottom, if soft, and the machine is hauled up. It weighs only a hundred pounds, yet a 12horse engine is required to haul in the line ata depth of two miles. Various other devices have heeu proposed. One attempted to ascertain the depth by exploding a heavy shell at the bottom, The time of the explosion and the time of the sound reaching the surface being known, the depth could readily he caleulatéd. This method seems to have been successful in shallow, but in deep water it was an utter failuve, as uo sound could he heard, Attempts havo been made to dispense with the line—a very desirable thing to be accomplished, because of the expense attending its use. One of tho latest inveutious is on tho atmospheric pressure principle, by Dr, A. W. Hall, of New York City, and dispenses with the line. It cousists of a tuhe closed at the top and open at the bottom, into which is inserted a graduated rod, As the instrument sinks, the increasing pressure causes the water to rise inthe tnbe and dissolve a substance coating the rod for the purpose. The height to which the water rises is thus marked on the rod and the depth indicated. The apparatus is carried to the bottom bya sinker, which is antoimatically detached by striking the bottom, and the instrument then rises by a float, Instruments constructed on the principle of the screw propeller have heen tested and failed, chiefly because the registering device could not he constructed sufficiently delicate, and at the samo time strong enough, to resist the pressure and action of the water upon it. An instrument of this class, lately invented, was exhibited at the late Fair of the American Institute. The spiral hlade is hung in an open framework, provided with outwardly projecting vertical wings, to prevent the whole mschine from turning as it descends to the hottom, The blade heing in au open frame is subject to the action of side currents, and the registering device is open to the ohjections which caused the failure of other instruments of this class. The writer, while preparing this paper, inyeuted two new sounding instruments. The first consists of a tube open at hoth ends, expanding ahout the center for the receptiou of a wheel, which moves on a horizontal axis. Above the tube is situated an air chamher open at the bottom; in the upper part of this chamber is located a registering device, which is econnected with the axis of the wheel. Theinstrument is kept in a vertical position by constructing it so that the center of gravity is below the tube. An automatically detachahle sinker carries the instrument to the bottom, As it descends, tho revolutions of the wheel record the depth. When the bottom is reached, the sinker is detached and the wheel locked. The wheel, protected hy the tuhe, and moving ona horizontal axis, is free from the action of side currents, and the registering device being frce from all contact with the water, records as accurately in the compressed air asin the open air. The air chamber not only protects the registering device, but it also answers as a float to raise the instrument. The other instrument is constructed on the pressure principle, and it is claimed will record the depth, however great, to a foot. In instruments constructed on the pressure principle, there is no danger of collapse when the pressnre is equalized within and without. In connection with any of the ahove instruments, ordinary dredges may he used. As soon as the paper was concluded, the ehair called upen Dr. Hall, who came on the platform and explained a full-sized bathometer, on the atmospheric principle, as deseribed in the paper. Mr. J. Fisher descrihed a bathometer invented hy Capt. Ericsson, and exbibitad before the American Institute about the year 1839. This device registered the depth of the ocean by tho compression of « column of water and filling the space thus made vacant hy mercury from another vessel. This small quantity of mereury, wheu weighed, approximates the depth to which the appatatus had descended. Some scientists douht the comprossihility of water, alleging that the apparent compressibility results from the air contained in the water and the porousness of the vessel containing it, thongh Jacob Perkins, some forty years ago, had demonstrated that water conld bocompressed perceptibly. If water is comprtossible, 2 column a mile deep would be cousiderably heavier at the hottom than at tho top, and would require a scale to be calculated accordingly, to estimate the depth, if the machine exhibited by Dr. Hall should he used. Dy. J. V. C. Smith spoke ai length on a geological formation that had attracted his attention, containing shells imbedded in solid limestone that were once, evidently, the bottom of the ocean, His description of such formations found in the stones of the great pyramids of Egypt, called forth applanse. The meeting adjourned till the 12th of January. ae Artiricran Licut.—The German chemist, Landsberg, says that artificial light contains 90 por cent. of calorific rays, while sunlight contains ouly 50. To this differenco he ascribes the disagreeable effect of artificial light upon the eyes. By passing the light through alum or mica, the calorific rays are intercepted, and this unpleasant efiect is obviated.

SCIENTIFIG “PRESS. [January 1, 1870. CONURURICALIONS. Dressing of Ores—A Freiberg Process. [Written for the Scientific Press.] The subject of dressing ores has received too little attention iu our country. Miners geuerally have worked only for the day, not intending to spend many years in tho business, aud trying to get out as much precious motal as possible iu a shori time, even ata great waste. This way of working answers perhaps for the early days of mining; hut a more ecarefnl and precise method must finally be adopted; and the sooner this is done, the hetter for the country. Many mines which cannot now bo worked at a profit might still he very lucrative if they had been properly worked at first. For mining improvements we naturally look to older couutries, where mining has long been a business. All our most valuahle hints have thus far come from other lands. The American really originates hut few theories or principles; hut he has a wonderful power of adaptiug, and making practical, old ideas, which, perhaps, have never before been successfully carried out. It is with the idea of saying something, from which useful hints may be extracted, that it is proposed to give one or two examples of the way ores are treated in Frei. berg. Of course no whole process can he bodily imported from a country where labor is as cheap as it isin Germany. Still it is thought that many of your readers who canuot goto Hurope will be glad to hear through yonr columns of what is really being done in tho old world, there being no English work extant which gives the details of the processes used. . Kiistel’s hook comes the uearest to this.—Ep. . The Chur Prinz Mine, Near Freiberg, will be taken as a good example—this mine bolonging to the government, and being worked for the purpose of promoting mining iuterests in general, rather than of hringing in a special revenue. Itis situated about five miles from Freiherg, close to the Mulde river; and in its general characteristics is nearer, perhaps, to the mines of Austin than to any others on the coast, The ore is principally argentiferous galena (with some gray copper ore containing silver), which occurs with iron pyrites, quartz, fluorspar and heavy spar. The country rock is gneiss, It is to be understood that the ore would be cousidered worthless here, not heing rich enough to be worked; but it must not be forgotten that the price of labor, on the other hand, is also very low. Scparation in the Mine. In the mine the ore is separated into three classes, and these are hoisted out sepatately. They are: Class A, “‘ separation ore;” class B, stamp mill ore; class C, harren rock, Af preseut, only the first elass will be spoken of, as class B undergoes a distinct treatment, aud the following remarks apply to this class (A) only. Reduction to a Proper Size and Sorting. The ore is first crushed in an ore-breakor modeled after Blake’s patent. The jaws of the machine play to and fro 213 times per minute, and are about 1'4 inches apart. The oro is thus brokeu up into pieces which range up to 1% eubic inches in size. These pieces aro brokeu up fiuer, to % cubic inches, in a second ore-crusher which plays 256 times per minute, and whose jaws are 34 inch apart. Itis thought that by crushing first more coarsely and then more finely, considerable is gained in an economical point of view. The crushed ore now falls into a set of four sieves, or swinging riddles, and is sorted into five classes. The sieves have a length of 834, 8, 64 and 4% feet, aud meshes 5-16, 3-16, 2-16 and 1-16 inches wide respectively. The swing is six inches, The finest dust is washed in a hand buddle, whichis 12 feet long, 30 iuches wide, and 22 inches deep; the rest go to the jigging machines, except that which will not pass through the coarsest sicve. This is carried by an elevator—consisting of huckets attached to an endless hand—to a rolling mill. This consists of two cast iron rollers, 9 inches wide aud 14 inches high, which require about two horse-power to drive them at tlic rate of 39 revolutious por minute. The ore falls through into a cylindrical trommel or drum, which revolves 18 times per minute and sorts into 5 different classes, the sieves having meshes respectively +4, 3-16, 44 and 1-16 inch wide. The finest product is washed in the hand buddle; the others are jigged. These special details are given hecause a proper sizing of the grains is all important for the foliowing processes, and too much stress cannot be laid on this point. Conld the grains be ohtained of exactly the same size, an almost perfect soparation would follow. It is not to be expected that we can work so thoroughly iu this country, where labor isso high; but still many will see how these and other processes may be shortened and eheapened to suit our circumstances, and yet do valuable work. Up to this point almost no manual labor is required, except in overseeing the working of the machines, Several workmen areemployed at the mine spoken of, but their numbers could easily be reduced to two or three. The Jigging Machines. The ore has now been sorted into four elasses, according to the size of the grains. These are carried to four different sets of jigging machines. The sieves of the first four machines have 16 meshes per sqnare inch; the second, 25 meshes; the third, 36 meshes; the fourth, 64 meshes. The stroke is ahout seven inches. All 16 machines use eight cuhie feet of water per minute. But only balf are at work at one time, as while one is working, the other is being cleaned out hy the hoy who has charge of a set of two, It takes three and a half to four minutes to treat each charge. In this country we would hardly be contented with thege machines. The jigging gives as products: Ist. Barren ore. 2d. Small graius, in which are still particles of ore mixed with rock, and which must be stamped finer with other stamp mill ore (to he described hereafter). 3d. Galena ore, which is pure euough to be sold. This contains 75 per cent. lead and about 0.05 per cent. silver, or about $19 to the ton. To drive all the machinery described, there isa 12-horse power steam engine, with 1414-ineh eylinderand 2% feet stroke, [fO BE CONTINUED.] dar ix Gas.—Professor Silliman and Wurtz have heen investigating the effects of atmospheric air upon the illumiuating power of gas, with, according to the Chemical News, the following results: ‘‘For any quantity of air less than five per cent., mised with gas, the loss in caudle power due to the addition of each one per cent., isa little over six-tenths of a candle (0'611 exactly); above that quantity the ratio of loss falls to half candle power for each additional one per cent. up to about twelve per cent. of air; above which, up to five per cent., the loss iu illuminating power is nearly four-tenths of a candle for each one per cent. of air added to the gas. With less than one-fourth of atmospheric air, not quite fifteen per cent. of the total illuminating power romains, and with between thirty and forty per cent., it totally disappears.” Tue Cours Purtosopny.—‘‘Iu the theory of positivism there is no room for metaphysics, nothing for tho metaphysician to do. Positivism has to do not simply with the facts of scicnce, the phenomena, but it aspires to be a general philosophy which shall express in a single formnla a uuiversal truth respecting all phenomena, It says you cannot know the absolute, the infinite; bnt you ean, by searching, find out the general law. It here sets its limit to speculation, and rules out the metaphysical and the supernatural; or, if it is goiug to fartosay that, it holds a position of indifforentism toward the supernatural. It bnilds its universal philosophy, if not

wholly upon the material, yet upon a necessary union of thought and matter. It admits no fact outside of experience,”— Courant, — Deep-Sea Sounding and Dredging. [Reported expressly for the Scientific Press. . The regular monthly meeting of the New York Society of Practical Engineering was held at the Cooper Institute, N. Y., on ‘Wednesday evening, December 8th, President James A. Whitney in the chair. The suhject of ‘‘Deep-Sea Sounding and Dredging” was discussed in an elaborate paper, by Prof. William Mohiuson, of Brooklyn. In his opening, the writer alluded to the vapid advancemcut of science within a few. years, and the mutual dependence of the physical sciences, Mavine geology has reeeived a new and important impulse since the laying of telegraph cables made it necessary to sound and dredge the ocean. But science has done comparatively little, as yet, by its researches in the ocean depths. As sounding and dredging, however, are an ahsolute necessity for the advancement of marine science and as a preparation for laying cables, it isof the greatest importance that the most perfect sounding devices should be invented. None heretofore used have been free from objection. The earliest sounder used was the common lead and line. It answers for shallow water, but is not reliahle beyond a depth of three or four hundred fathoms. In 1818, Sir John Ross procured shells, shrimps and other crustaceans from the hottom of Baffln’s Bay, in water more than 650 fathoms deep. In 1830, Vidal carried dredging successfully to a depth of 200 fathoms, and in 1841, Admiral Sir J. C. Ross procured a variety of invertehrate marine animals from the bottom of the Antaretie Ocean at a depth of 270 fathoms. But all the old souuders were crude, and could not be used successfully in very deep water, America has been the pioneer in deepsea sounding, and it was not until 1858 that the secrets of the deep ocean bed wererevealed. In that year, Midshipman Mitchell, on board the U. 8. hrig Dolphin, hrought up ooze composed of the remains of microscopie animals, from the bottom of the Atlantic, where the water was 1,700 fathoms, or about two miles deep. Devices for Deep Sounding. The device heretofore most extensively used in the United States, and, with some modifications, also in the British Navy, for deep sounding, is an iuvention of Lieut. Brookes, of the U. 8. Navy. It consists of arod, to the upper end of whichis attached a hoavy ball, hollowed out to receive it, the lower end of the rod being provided witha eup containing a valve. When the instrument strikes the bottom, the hall falls off, the cup fills with the ooze of the bottom, if soft, and the machine is hauled up. It weighs only a hundred pounds, yet a 12horse engine is required to haul in the line ata depth of two miles. Various other devices have heeu proposed. One attempted to ascertain the depth by exploding a heavy shell at the bottom, The time of the explosion and the time of the sound reaching the surface being known, the depth could readily he caleulatéd. This method seems to have been successful in shallow, but in deep water it was an utter failuve, as uo sound could he heard, Attempts havo been made to dispense with the line—a very desirable thing to be accomplished, because of the expense attending its use. One of tho latest inveutious is on tho atmospheric pressure principle, by Dr, A. W. Hall, of New York City, and dispenses with the line. It cousists of a tuhe closed at the top and open at the bottom, into which is inserted a graduated rod, As the instrument sinks, the increasing pressure causes the water to rise inthe tnbe and dissolve a substance coating the rod for the purpose. The height to which the water rises is thus marked on the rod and the depth indicated. The apparatus is carried to the bottom bya sinker, which is antoimatically detached by striking the bottom, and the instrument then rises by a float, Instruments constructed on the principle of the screw propeller have heen tested and failed, chiefly because the registering device could not he constructed sufficiently delicate, and at the samo time strong enough, to resist the pressure and action of the water upon it. An instrument of this class, lately invented, was exhibited at the late Fair of the American Institute. The spiral hlade is hung in an open framework, provided with outwardly projecting vertical wings, to prevent the whole mschine from turning as it descends to the hottom, The blade heing in au open frame is subject to the action of side currents, and the registering device is open to the ohjections which caused the failure of other instruments of this class. The writer, while preparing this paper, inyeuted two new sounding instruments. The first consists of a tube open at hoth ends, expanding ahout the center for the receptiou of a wheel, which moves on a horizontal axis. Above the tube is situated an air chamher open at the bottom; in the upper part of this chamber is located a registering device, which is econnected with the axis of the wheel. Theinstrument is kept in a vertical position by constructing it so that the center of gravity is below the tube. An automatically detachahle sinker carries the instrument to the bottom, As it descends, tho revolutions of the wheel record the depth. When the bottom is reached, the sinker is detached and the wheel locked. The wheel, protected hy the tuhe, and moving ona horizontal axis, is free from the action of side currents, and the registering device being frce from all contact with the water, records as accurately in the compressed air asin the open air. The air chamber not only protects the registering device, but it also answers as a float to raise the instrument. The other instrument is constructed on the pressure principle, and it is claimed will record the depth, however great, to a foot. In instruments constructed on the pressure principle, there is no danger of collapse when the pressnre is equalized within and without. In connection with any of the ahove instruments, ordinary dredges may he used. As soon as the paper was concluded, the ehair called upen Dr. Hall, who came on the platform and explained a full-sized bathometer, on the atmospheric principle, as deseribed in the paper. Mr. J. Fisher descrihed a bathometer invented hy Capt. Ericsson, and exbibitad before the American Institute about the year 1839. This device registered the depth of the ocean by tho compression of « column of water and filling the space thus made vacant hy mercury from another vessel. This small quantity of mereury, wheu weighed, approximates the depth to which the appatatus had descended. Some scientists douht the comprossihility of water, alleging that the apparent compressibility results from the air contained in the water and the porousness of the vessel containing it, thongh Jacob Perkins, some forty years ago, had demonstrated that water conld bocompressed perceptibly. If water is comprtossible, 2 column a mile deep would be cousiderably heavier at the hottom than at tho top, and would require a scale to be calculated accordingly, to estimate the depth, if the machine exhibited by Dr. Hall should he used. Dy. J. V. C. Smith spoke ai length on a geological formation that had attracted his attention, containing shells imbedded in solid limestone that were once, evidently, the bottom of the ocean, His description of such formations found in the stones of the great pyramids of Egypt, called forth applanse. The meeting adjourned till the 12th of January. ae Artiricran Licut.—The German chemist, Landsberg, says that artificial light contains 90 por cent. of calorific rays, while sunlight contains ouly 50. To this differenco he ascribes the disagreeable effect of artificial light upon the eyes. By passing the light through alum or mica, the calorific rays are intercepted, and this unpleasant efiect is obviated.