Volume 35 (1877) (426 pages)

September 8, 1877.] MINING AND SCIENTIFIC PRESS. 147 GP tad fe? MecHANicaL ‘PROGRESS. A Screw Ventilator. Whether eld Archimedes theught his screw could be employed to lift bad air nut of ‘‘ public bnildings, dwellings and cow-heuses,” may be a question, but thus it has been applied. We read of an English inveution in which a acrew, made to revolve within a eylindrical casing, will cause a current upwards or dowawards aecording tn the direction given to the thread or blade. 11 this case the dirvction is, of course, upwards; and the serew is arranged on a spindle, The spindlo is prolonged upwants, and to its top is attached a dished hood provided with vanca, which are acted upoa by the wiud, thus causin tho spindlo to revolve. Between the hoo an: the screw are other perpeudicular vaues, arrauged round a eircumnferenco akout equal te the screw casing. These vanes vontribute to the motive power; also sllow of the eseape hotweeu them vf the vitiated air withdrawn hy the screw. They are disposed so as to overlap each ether, while at the same timo allowing a space between, in sucha way as to exclude hail, rain, snow or dust, while they also provent any down draught. Tho centers of the spindles aro conical and of steel hardeued bya secret process, revolying in steps nf tho szme substance; they run iu oil enps, the reservo rs of which contain euough nil fete for eight tu teu years. ludeed, we are informed that sane ventilators nu this principlo have been run without attention for l4 years. The eonseqience of the friction being tbus reduced toa minimum is that the ventilators will revnlve witb the least breath of wind, and meteorological reeords inform us that the wiid is never absolutoly (still; so that, with these appl ances, we may rely upon a constant changing of the stmosphcro iu the room to which they are applied. There is an arrangenent for driving the screw hy power whun very active ventilation s required, ospovially for expolling accumulaticns or large quantities of hot air and snlphurous gases; dirt, dust and waste flyings; and injurious effluvia from gasing and other workrooms, AYsTRALIA AND Amenica.—A correspondent, writing to The London Times from Sydney, says: ‘Onr appearance at Pbiladeiphia has drawn the attention of Ameriean manufacturers to us in a most marked and unexpected degree. A country that, like New South Wales, is rolling in wealth, mnst be a country that is able to buy, and a country that is able to buy is exactly the country tbat American manufacturers have heen anxiously looking out for. Our representatives at Philadelphia bave come back strongly impressed witb the fact that tbere are many things the Americans can supply us with advantage. Our government has an offer from Messrs. Baldwin & Uo. to furnish a locomotive engine for about £1,000 less than the cost of an Englisb engine, and to leave the paymont open until the ee bas been thoroughly proved and approved. A Pullman’s sleeping car and an ordinary passenger car have already been ordered, and American wheels, axles, rails, and hrakes are strongly pressed on our acceptance. As our government engineers are all of the English school, American novelties will havea bard hattle to fight to win official acceptance, but the demand for economy in railway construction and worsing is so great that people and Parliament will press on the Minister for Public Works a fair trial for any American novelties that may seem to be suited to our wants. Tbe Englisb manufacturers, therefore, who have hitherto supplied us, must look to their laurels.” Bronze For VALVES anp Cocks.—The question of the bestalloy for steam-engine valves and cocks has been discussed before the Vienna Association of Mechanical Engineers. The following were submited as the mest durable alloys: I. Copper, $4; tin, 2.9; zinc, 8.3; lead, 4.3; iron, 0.4. II. Copper, 83; tin, 17. 111. Copper, 80; tin, 18;zinc, 2. If after casting, and while still red hot, cold water is poured over the bronze, it becomes harder and finer in grain, and tougher, as tbe tin, instead of separating out, as happens when the bronze cools slowly, remains mixed, and the alloy retains its comactness. The toughness and quality of the rouze are stated to be very considerably increased by tbis method of treatment, to which the alloy No. II. is more especially susceptible. Prizes FoR ALLoys.—The Council of the Prussian Association for the Promotion of Industry announce that they will award the following prizes this year and next: For the best series of alloys of iron and manganese, £100; for a process for separating cyanide and ferocyanide of potassium from sulpho-cyanide of ammonium by means of potassium compounds, £50; for a process for utilizing antbracite oils in the preparatiou of auiline and alizarin, £75. CuraninG Iron Wire.—Betz, of St. Ingbert, has constructed an apparatus for freeing iron wire by mechanical means from forge scale. The process consists in drawing wire over rollers, which remové the scale from it on each of its sides by mere pressure, the last step in the process being to pass it through a hox containing sand and calf-hair, whence it is wound on bobbins. The wire is said not to sufler in qnality by the manipulation it undorgoes, Ow Fites.—A writer for the Pelytechnic Reriew notes the following pnints: lo using a new file, tho pressure omployed at tirst should bu eemparatively light, until the very sharp edges of the teeth have been removed; after which, struuger pressure and deeper cut may be made withnut injury to tho teeth. But if the teeth have, hard usage put upou them while their edges are keen and penetrating, they are likely to take hold more strougly and hecome breken off at the root. A few careless strukea may damage a new file sn as to take away half the “life” of tho firat entting. The skins of castings are not only ‘‘chilled,” and hence harder than tho interior, but aro often glazed with a Vitreous surface, in which, also, gritty particles are imbedited. No new file should be nsed on such surfaces, ner on welds whero borax or vitreous fluxes have becn used, uor on oxidized surfaces; but a worn file shouRl be nsed to attack such work, which will scarecly harm it. For filing steol, grades coarser thau sccond ent arc apt to be too ‘hoggish;” steol cannot be Uived off like brass or iron, and tho same cut nf tile should not he usod on steel and on iron, auy inore than on hrass and iron, nr horn and iron. In huying tiles, see that sull weight is given, especially whore recutting is to bu done, While a lout file will hardly stand one recutting, one that is full weight will bear re. cutting two or three times, American Toous.—In his review of the late World’s Fair at Philadelphia, Francis A. Walker says: ‘' In cdge tools the supremacy of the United States is so complete, that, as is well known, foreigu producers have heen largely driven to imitate the geueral stylo of our goods, and even at copy trademarks. ‘In the mannfacture of steel,” says Prof. Reuleanx, ‘‘the United States takes unquestiouably the first place to the Exhibition; in singlo brancbes of this manufacture their priority is even absolute. The axes, hatchets, files, the tools for forestry, plantations and gardening, and the like, are preseuted in such variety and beauty as compels ns to stand and gazo with wonderment. The saws, beth plain and circular, with all the fine, yea, refined singularities possible in this department, together with steel tools for the masou, the molder, the statuary and the machinist, are of the first order in merit. I will also add, that the larger sawing machines, the cross-saws, the block-saws, and the like, have reached a hight of developmeut from which we are still far distant.” AGRICULTURAL IMPLEMENTS iN Russi1a.— The United States Consul at Odessa recently wroto to the State Department at Washington that “implements of agriculture might come in great quantities to this country if our manufacturers would make an effort iu that direction, and adapt their imnlements for the use of the peasantry of this country. The principal thing to be done is to make them exceedingly firm and strong. American reapers and mowers are now the favorites above all others, and bave a large sale, In other machiuery .the English manufacturers have the field, and I have seen no article of their machinery that excels the American, unless expensiveness may be deemed an excellence. Iam persuaded that there is a fine field here for the American threshing machine.” A Noiss Extincursaer.—Everybody tbat travels has experienced the annoyance of having his ears deafened on board a steamboat by the roar of escaping steam. Sometimes accidents have oceurred during the racket of ‘‘hlowing off” simply hecause the captain cannot make his orders heard, and everytbing has to be done in dumb show while tbe disturbance lasts. Happily, says the American Manufacturer, an invention called the spiral exhaust nozzle is destined to choke off the noise. It operates by hreaking the waves of sonnd, the Se steam being surrounded with a wire helix, an obliged to pass between the wires. These nozzles are in use on steamera running between Philadelphia and Eugland. Pxreumatic Hoist.—M. Blanchet, the manager of the Kpinav collieries (Saone-et-Loire), has sunk a shaft 656 yards deep and placed in it a tube formed of iron plates, in which travels a tightly packed piston capable of carrymg on its upper surface a load of 10 tons. When loaded, a vacuum is made above it, and it is driven up, bringing the drawing cage with it. The fuel tips os removed and replaced by empty ones, and atmospheric pressure is applied to effect the descent of the piston. The latter is kept in place by vertical guides, Train TELEGRAPH.—A patent electric system, says the Railread Gazette, has lately been intradnced on the trains of the Philadelphia, Wilmington and Baltimore railroad. ‘This system supersedes the present hell and cord arrangement to communicate with the engineer, and also gives a continuous automatic alarm on the locomotive whenever any portiou of tbe train becomes accidentally detached. The arrangement is also applied to freight trains. Nove, Pirate Work.—On the 30th of June an exhihition of novelties in connection with the metal trades, more especially plate working, was opened in the Schutzenham at Leipzig. Amongst objects exhibited were a fountain throwing a jet three feet high by meaus of solidly made clockwork; decorated tinplate for various purposes, capahle of resisting stron heats; wire-inserters, ete. Improved tools ani implements of various sorts were also exhibited. 3 CIENTIFIC ‘PRocress. Moons for Mars. An astronomical discovery, whieh is ranked among the greatest of this century, has beon made at the observatory at Washington, hy means of the ucw instrument which is called the “great telescope.” Accounts which came to hand enable us to compile the following niteresting narrative ; About 11 oclock, on Thursday night, August 16th, Professor Hall noticed a very small star following Mars a few seconds, and mado an estimate of its distauce frem tho planet. Two hours later he looked agaiu, and was surrised to find that the star scemed to be follow. lug the planet. As the distance had not increased, while the planet was moving away at the rate of 15 seconds an hour, he therefore made a careful series of measures, which showed that the satellito was 80 seconds froin tbe lauet. An honr Inter it was still there, but Mr. Hall made no further observation, hardly crediting the great discovery he had made. On Friday morning he showed his observa. tions to Professor Newcomb, who was so confident that the ohject must bo a satcllite, that ho calculated roughly the time of its revolution, which he fied at oue day, eight hours, or a little less, This sbowed that the ebject would pass behind the pee some time during the following night, aud that if not seen in early evening, it would reappear before daylight in the morning. In the evening it was invisible, but reappeared, true to the predictien, about eue o'clock in the morning with a companion satellite. Professor Hall bad now so little doubt of the reality of the object, that he made the discovery known to Admiral Rogers, the superintendent. It was still thought best to wait for another look before formally announcing the discovery, especially as Professor Newcomh’s calculation showed tbat it would be on the opposite side of the planet ou Saturday evening. Hardly was the telescone turned on Mars, when tho satellite Was seeu, and its position determined by several of the astronomers. Scientific autborities in Washington regard this as ranking among tbe greatest telescopic discoveries of the century; the only two which exceed it being that of the asteroid group in 1801, and of the planet Neptune in 1846. Professor Hall, the fortunate discoverer of the satellite, has been attached to the ohservatory since 1862. When Professor Newcomhe resigned the charye of the great telescope, in 1875, he succeeded to it. e is an able and learned mathematician, and au unostentatious and conscientious observer, Professor Hall, who has kept contiuuous watch at the instrument for a week, furnishes the following statement : “The first satellite of Mars was discovered at the naval observatory, in Wasbington, on tho night of August 16tb. It was first seen ‘at 42 minutes past 1] o’clock. It has been nbserved on tbe nights of the 16th, 17th and 18th of August, The time of the revolution of this satellite about Mars is about 30 bours. Its greatest apparent distance from tbe center of Mars is 80 seconds of are. I think I saw another satellite on Saturday morning aboutfour o'clock, but of the existence of this second satellite Iam not absolutely certain. I believe, bowever, that there are two, and J expect to be able to determine this to-night, as I eommence observations again about midnight. The satellite, in its appearance, is a faint object of about the size of a star of the 13th or 14th magnitude, and it was possible to discover it only by putting Mars, whicb is now exceedingly bright, ont of the field of tbe telescope, so as to get rid of the brilliant light of that planet.” The distance of the first satellite from the planet is between 14,000 and 15,000 miles, which is less than that of any other known satellite from its primary, and only about onesixteeuth the distance of the moon from tbe earth. The inner one, as to the existence of which tbe astronomers are not yet absolutely certain, is still closer. The diameter of the new satellite is very sinall, probably not more than 50 or 100 miles. The following dispatch announces officially the discovery of the new satellites : Wastinatox, August 19th.—Two satellites of Mars have been discovered by Hall, at Washington. First, clongation west, August 18th, 11 hours, Washington tinie: distance 80 seconds; period, 30 hours. Distance of second, 50 seconds. Jusern HENRY. Misstne Istanns.—Tho news of tbe vanishing of the Barker islands and their inbabitants from tbe northwestern coast of Australia, says fren, will puzzle those geologists who assume that hecause a place lies ont of a known line of volcanic action, it must therefore be safe. Whatever may be supposed to he tbe case now, Western Australia betrays many traces of former volcanic action, and the disappearance of the Barker islands can hardly he regarded as a greater marvel than that of Stromboli, It is an unfortunate accideut for Captain Fisher— the Tasmanian capitalist, who purchased from the West Australian government the right to remove guano from the islands in question. In April Jast, he dispatched three vessels with laborers and appliances for shipping the guanw; but, after cruising ahont for some time in latitude 14° S, longitude 125° E., they could not make out the islands, which ought to have been there. How aud when the islands disappeared is at present unknown, and it is not very prohable that any evidence will be added to that uow before the public. Venus’ Slippers. Mr. F. Buckland, in Land and Water, says: “These slippers are far more beautiful than anything ever yet turued ont in the worksbop of a London or Parisian ladies’ bootmaker. They are found floating far out at sea in the Mediterranean, on tle Freneh eoast. Each slipper is about an inch aud a half in length, and half an inch in the widest part. They are of a lovely glass-like consistence, and ina ccrtain Hight resplendent like jelly-fish. They are the shape of a handsome shoe; the edge of the shoe projects in a very ornamental dentated margiu, and the toc part is highly nrnamental, as if witb embroidery insertiou. Mr, M. Latham says: ‘It is a kind of jelly-tisb ; I have had considerable difficulty iu finding ont its real nature. At last I ascertaiued that it is nne of the pteropoda, or wing-footed molluscs.’ The Rev. J. Wned writes: ‘These are so-called from tbe fin-like lohes that project from the sides, and are evidently analogons to the similar organs in some nf the sea snails, These appendages are used almost like wings, the creature flapping its way vigorously through tho water, just as a hutterfly urges its devious course through tbe air, They aro found in the hotter seas, swimming boldly in vast multitudes amid the wide waters, and one species (Clie bereatis) bas long been celebrated as furnishing the huge Greenland whale witb the greater part of its subsistence. Tbe scientilic name of it is cymbulia, so enlled on aceount of its being so like a boat.’ We read : ‘Cuvier describes the cymbulia as baving a cartilaginous or gelatinous envelepe in the form of a boat or slipper, beset witb points in longitudinal rows; and the animal as possessing two great wings, whicb are at once branchiw and fins, and between them on tbe open side, a third smaller lobe, which is three-pointed. The mouth, provided witb two small tentacula, is placed between the wings towards the shut side of the cell, and above are two small eyes. The transparency of the texture permits the internal organs to be distinguished with great facility. The sbell is cartilaginous, translucent, oblong in the form of a slipper, and ontirely covered witb a delicate and scarcely visible membraue.’ “These slippers of tbe Marine Venus are so beautiful in form and structure that I propose, if possible, to have a model of them cut in crystal. In the form of ear-rings they would make very pretty ornaments, as showing chaussure of Cinderella of the ocean.” Astronomical Work in Washington. The editor of the American Manufacturer bas made ‘‘an excursion” to Wasbington and took these notes: ‘‘We visited the Naval Observatory, and saw there several objects of interest. Among them was tbe equatorial telescope, said to be the largest in the world. Itis 32 feet 8 inches in length, with an object glass of 26 inches in diameter, clear aperture It was made by Alvin Clark, of Cambridge, Mass., in 1873, ‘We saw there also the standard astronomical clock whicb keeps tbe time for the Observatory, and#from which Wasbington mean time is telegrapbed every day to all parts of the country. To keep tbis clock from sudden ebanges of temperature it is inclosed by a thick wall nf masonry, and to keep tbe wall free from moisture a coal fire is coustantly kept burning in tbe room. “The records of tbe transit of Venus are being worked up hy the offieers in charge of tbe Observatory. Few have any idea of tbo immense amount of lahor expended in this direction. It includes microscopic measurement of a large number of pbotographs of tbe transit, which have to be made witb expensive and complicated apparatus especially designed for the purpose. Most of this apparatus is entirely novel, and is the invention of Prof. William Harkness, wbo was one of the chief officers of the transit expedition. Tbe cbronometers used by vessels of the navy are all tested and their rate of error recorded at this Observatory. We saw a large number of these instruments, which were made by tbe principal manufacturers of tbis country and Europe, and were told those made hy a certain firm in New York are superior in every respect to tbose of foreign manufacture.” Nornensksoip’s Next Expenrnmon. — For Professor Nordenskjold’s expedition, whicb is to set out from Gothenburg, in Sweden, in June, 1878, a vessel has already been chartered for 150,000 Swedish crowns (about $25,000.) King Oscar has contributed 50,000 crowns from bis personal revenue, but tbe burden of the expense will be borne by the friend and patron of Nordenskjold, a merchant of Gothenburg named Dickson. The ronte of the expedition will be from its starting point to the North Cape, thence eastwardly througb the Polar Sea to and through Behring’s Strait; thence along the eastern and soutbern coasts of Asia, tbrougb the Red Sea, the Suez Canal, and the Mediterranean Sea to the Atlantic Ocean, and return home in the autumn of 1879. This looks like a voyage of general discovery, and if tbe North Pole should be struck, all the better. He can hang the Swedisb flag upon it. Spectrum or Exectric Ladut,—M,. P. Desains finds that the spectra of electric light are very similar to those of the solar rays. They are less extensive, particularly on the side of the violet; but the curves of intensity exbibit but slight differences in the region of greatest heat.

September 8, 1877.] MINING AND SCIENTIFIC PRESS. 147 GP tad fe? MecHANicaL ‘PROGRESS. A Screw Ventilator. Whether eld Archimedes theught his screw could be employed to lift bad air nut of ‘‘ public bnildings, dwellings and cow-heuses,” may be a question, but thus it has been applied. We read of an English inveution in which a acrew, made to revolve within a eylindrical casing, will cause a current upwards or dowawards aecording tn the direction given to the thread or blade. 11 this case the dirvction is, of course, upwards; and the serew is arranged on a spindle, The spindlo is prolonged upwants, and to its top is attached a dished hood provided with vanca, which are acted upoa by the wiud, thus causin tho spindlo to revolve. Between the hoo an: the screw are other perpeudicular vaues, arrauged round a eircumnferenco akout equal te the screw casing. These vanes vontribute to the motive power; also sllow of the eseape hotweeu them vf the vitiated air withdrawn hy the screw. They are disposed so as to overlap each ether, while at the same timo allowing a space between, in sucha way as to exclude hail, rain, snow or dust, while they also provent any down draught. Tho centers of the spindles aro conical and of steel hardeued bya secret process, revolying in steps nf tho szme substance; they run iu oil enps, the reservo rs of which contain euough nil fete for eight tu teu years. ludeed, we are informed that sane ventilators nu this principlo have been run without attention for l4 years. The eonseqience of the friction being tbus reduced toa minimum is that the ventilators will revnlve witb the least breath of wind, and meteorological reeords inform us that the wiid is never absolutoly (still; so that, with these appl ances, we may rely upon a constant changing of the stmosphcro iu the room to which they are applied. There is an arrangenent for driving the screw hy power whun very active ventilation s required, ospovially for expolling accumulaticns or large quantities of hot air and snlphurous gases; dirt, dust and waste flyings; and injurious effluvia from gasing and other workrooms, AYsTRALIA AND Amenica.—A correspondent, writing to The London Times from Sydney, says: ‘Onr appearance at Pbiladeiphia has drawn the attention of Ameriean manufacturers to us in a most marked and unexpected degree. A country that, like New South Wales, is rolling in wealth, mnst be a country that is able to buy, and a country that is able to buy is exactly the country tbat American manufacturers have heen anxiously looking out for. Our representatives at Philadelphia bave come back strongly impressed witb the fact that tbere are many things the Americans can supply us with advantage. Our government has an offer from Messrs. Baldwin & Uo. to furnish a locomotive engine for about £1,000 less than the cost of an Englisb engine, and to leave the paymont open until the ee bas been thoroughly proved and approved. A Pullman’s sleeping car and an ordinary passenger car have already been ordered, and American wheels, axles, rails, and hrakes are strongly pressed on our acceptance. As our government engineers are all of the English school, American novelties will havea bard hattle to fight to win official acceptance, but the demand for economy in railway construction and worsing is so great that people and Parliament will press on the Minister for Public Works a fair trial for any American novelties that may seem to be suited to our wants. Tbe Englisb manufacturers, therefore, who have hitherto supplied us, must look to their laurels.” Bronze For VALVES anp Cocks.—The question of the bestalloy for steam-engine valves and cocks has been discussed before the Vienna Association of Mechanical Engineers. The following were submited as the mest durable alloys: I. Copper, $4; tin, 2.9; zinc, 8.3; lead, 4.3; iron, 0.4. II. Copper, 83; tin, 17. 111. Copper, 80; tin, 18;zinc, 2. If after casting, and while still red hot, cold water is poured over the bronze, it becomes harder and finer in grain, and tougher, as tbe tin, instead of separating out, as happens when the bronze cools slowly, remains mixed, and the alloy retains its comactness. The toughness and quality of the rouze are stated to be very considerably increased by tbis method of treatment, to which the alloy No. II. is more especially susceptible. Prizes FoR ALLoys.—The Council of the Prussian Association for the Promotion of Industry announce that they will award the following prizes this year and next: For the best series of alloys of iron and manganese, £100; for a process for separating cyanide and ferocyanide of potassium from sulpho-cyanide of ammonium by means of potassium compounds, £50; for a process for utilizing antbracite oils in the preparatiou of auiline and alizarin, £75. CuraninG Iron Wire.—Betz, of St. Ingbert, has constructed an apparatus for freeing iron wire by mechanical means from forge scale. The process consists in drawing wire over rollers, which remové the scale from it on each of its sides by mere pressure, the last step in the process being to pass it through a hox containing sand and calf-hair, whence it is wound on bobbins. The wire is said not to sufler in qnality by the manipulation it undorgoes, Ow Fites.—A writer for the Pelytechnic Reriew notes the following pnints: lo using a new file, tho pressure omployed at tirst should bu eemparatively light, until the very sharp edges of the teeth have been removed; after which, struuger pressure and deeper cut may be made withnut injury to tho teeth. But if the teeth have, hard usage put upou them while their edges are keen and penetrating, they are likely to take hold more strougly and hecome breken off at the root. A few careless strukea may damage a new file sn as to take away half the “life” of tho firat entting. The skins of castings are not only ‘‘chilled,” and hence harder than tho interior, but aro often glazed with a Vitreous surface, in which, also, gritty particles are imbedited. No new file should be nsed on such surfaces, ner on welds whero borax or vitreous fluxes have becn used, uor on oxidized surfaces; but a worn file shouRl be nsed to attack such work, which will scarecly harm it. For filing steol, grades coarser thau sccond ent arc apt to be too ‘hoggish;” steol cannot be Uived off like brass or iron, and tho same cut nf tile should not he usod on steel and on iron, auy inore than on hrass and iron, nr horn and iron. In huying tiles, see that sull weight is given, especially whore recutting is to bu done, While a lout file will hardly stand one recutting, one that is full weight will bear re. cutting two or three times, American Toous.—In his review of the late World’s Fair at Philadelphia, Francis A. Walker says: ‘' In cdge tools the supremacy of the United States is so complete, that, as is well known, foreigu producers have heen largely driven to imitate the geueral stylo of our goods, and even at copy trademarks. ‘In the mannfacture of steel,” says Prof. Reuleanx, ‘‘the United States takes unquestiouably the first place to the Exhibition; in singlo brancbes of this manufacture their priority is even absolute. The axes, hatchets, files, the tools for forestry, plantations and gardening, and the like, are preseuted in such variety and beauty as compels ns to stand and gazo with wonderment. The saws, beth plain and circular, with all the fine, yea, refined singularities possible in this department, together with steel tools for the masou, the molder, the statuary and the machinist, are of the first order in merit. I will also add, that the larger sawing machines, the cross-saws, the block-saws, and the like, have reached a hight of developmeut from which we are still far distant.” AGRICULTURAL IMPLEMENTS iN Russi1a.— The United States Consul at Odessa recently wroto to the State Department at Washington that “implements of agriculture might come in great quantities to this country if our manufacturers would make an effort iu that direction, and adapt their imnlements for the use of the peasantry of this country. The principal thing to be done is to make them exceedingly firm and strong. American reapers and mowers are now the favorites above all others, and bave a large sale, In other machiuery .the English manufacturers have the field, and I have seen no article of their machinery that excels the American, unless expensiveness may be deemed an excellence. Iam persuaded that there is a fine field here for the American threshing machine.” A Noiss Extincursaer.—Everybody tbat travels has experienced the annoyance of having his ears deafened on board a steamboat by the roar of escaping steam. Sometimes accidents have oceurred during the racket of ‘‘hlowing off” simply hecause the captain cannot make his orders heard, and everytbing has to be done in dumb show while tbe disturbance lasts. Happily, says the American Manufacturer, an invention called the spiral exhaust nozzle is destined to choke off the noise. It operates by hreaking the waves of sonnd, the Se steam being surrounded with a wire helix, an obliged to pass between the wires. These nozzles are in use on steamera running between Philadelphia and Eugland. Pxreumatic Hoist.—M. Blanchet, the manager of the Kpinav collieries (Saone-et-Loire), has sunk a shaft 656 yards deep and placed in it a tube formed of iron plates, in which travels a tightly packed piston capable of carrymg on its upper surface a load of 10 tons. When loaded, a vacuum is made above it, and it is driven up, bringing the drawing cage with it. The fuel tips os removed and replaced by empty ones, and atmospheric pressure is applied to effect the descent of the piston. The latter is kept in place by vertical guides, Train TELEGRAPH.—A patent electric system, says the Railread Gazette, has lately been intradnced on the trains of the Philadelphia, Wilmington and Baltimore railroad. ‘This system supersedes the present hell and cord arrangement to communicate with the engineer, and also gives a continuous automatic alarm on the locomotive whenever any portiou of tbe train becomes accidentally detached. The arrangement is also applied to freight trains. Nove, Pirate Work.—On the 30th of June an exhihition of novelties in connection with the metal trades, more especially plate working, was opened in the Schutzenham at Leipzig. Amongst objects exhibited were a fountain throwing a jet three feet high by meaus of solidly made clockwork; decorated tinplate for various purposes, capahle of resisting stron heats; wire-inserters, ete. Improved tools ani implements of various sorts were also exhibited. 3 CIENTIFIC ‘PRocress. Moons for Mars. An astronomical discovery, whieh is ranked among the greatest of this century, has beon made at the observatory at Washington, hy

means of the ucw instrument which is called the “great telescope.” Accounts which came to hand enable us to compile the following niteresting narrative ; About 11 oclock, on Thursday night, August 16th, Professor Hall noticed a very small star following Mars a few seconds, and mado an estimate of its distauce frem tho planet. Two hours later he looked agaiu, and was surrised to find that the star scemed to be follow. lug the planet. As the distance had not increased, while the planet was moving away at the rate of 15 seconds an hour, he therefore made a careful series of measures, which showed that the satellito was 80 seconds froin tbe lauet. An honr Inter it was still there, but Mr. Hall made no further observation, hardly crediting the great discovery he had made. On Friday morning he showed his observa. tions to Professor Newcomb, who was so confident that the ohject must bo a satcllite, that ho calculated roughly the time of its revolution, which he fied at oue day, eight hours, or a little less, This sbowed that the ebject would pass behind the pee some time during the following night, aud that if not seen in early evening, it would reappear before daylight in the morning. In the evening it was invisible, but reappeared, true to the predictien, about eue o'clock in the morning with a companion satellite. Professor Hall bad now so little doubt of the reality of the object, that he made the discovery known to Admiral Rogers, the superintendent. It was still thought best to wait for another look before formally announcing the discovery, especially as Professor Newcomh’s calculation showed tbat it would be on the opposite side of the planet ou Saturday evening. Hardly was the telescone turned on Mars, when tho satellite Was seeu, and its position determined by several of the astronomers. Scientific autborities in Washington regard this as ranking among tbe greatest telescopic discoveries of the century; the only two which exceed it being that of the asteroid group in 1801, and of the planet Neptune in 1846. Professor Hall, the fortunate discoverer of the satellite, has been attached to the ohservatory since 1862. When Professor Newcomhe resigned the charye of the great telescope, in 1875, he succeeded to it. e is an able and learned mathematician, and au unostentatious and conscientious observer, Professor Hall, who has kept contiuuous watch at the instrument for a week, furnishes the following statement : “The first satellite of Mars was discovered at the naval observatory, in Wasbington, on tho night of August 16tb. It was first seen ‘at 42 minutes past 1] o’clock. It has been nbserved on tbe nights of the 16th, 17th and 18th of August, The time of the revolution of this satellite about Mars is about 30 bours. Its greatest apparent distance from tbe center of Mars is 80 seconds of are. I think I saw another satellite on Saturday morning aboutfour o'clock, but of the existence of this second satellite Iam not absolutely certain. I believe, bowever, that there are two, and J expect to be able to determine this to-night, as I eommence observations again about midnight. The satellite, in its appearance, is a faint object of about the size of a star of the 13th or 14th magnitude, and it was possible to discover it only by putting Mars, whicb is now exceedingly bright, ont of the field of tbe telescope, so as to get rid of the brilliant light of that planet.” The distance of the first satellite from the planet is between 14,000 and 15,000 miles, which is less than that of any other known satellite from its primary, and only about onesixteeuth the distance of the moon from tbe earth. The inner one, as to the existence of which tbe astronomers are not yet absolutely certain, is still closer. The diameter of the new satellite is very sinall, probably not more than 50 or 100 miles. The following dispatch announces officially the discovery of the new satellites : Wastinatox, August 19th.—Two satellites of Mars have been discovered by Hall, at Washington. First, clongation west, August 18th, 11 hours, Washington tinie: distance 80 seconds; period, 30 hours. Distance of second, 50 seconds. Jusern HENRY. Misstne Istanns.—Tho news of tbe vanishing of the Barker islands and their inbabitants from tbe northwestern coast of Australia, says fren, will puzzle those geologists who assume that hecause a place lies ont of a known line of volcanic action, it must therefore be safe. Whatever may be supposed to he tbe case now, Western Australia betrays many traces of former volcanic action, and the disappearance of the Barker islands can hardly he regarded as a greater marvel than that of Stromboli, It is an unfortunate accideut for Captain Fisher— the Tasmanian capitalist, who purchased from the West Australian government the right to remove guano from the islands in question. In April Jast, he dispatched three vessels with laborers and appliances for shipping the guanw; but, after cruising ahont for some time in latitude 14° S, longitude 125° E., they could not make out the islands, which ought to have been there. How aud when the islands disappeared is at present unknown, and it is not very prohable that any evidence will be added to that uow before the public. Venus’ Slippers. Mr. F. Buckland, in Land and Water, says: “These slippers are far more beautiful than anything ever yet turued ont in the worksbop of a London or Parisian ladies’ bootmaker. They are found floating far out at sea in the Mediterranean, on tle Freneh eoast. Each slipper is about an inch aud a half in length, and half an inch in the widest part. They are of a lovely glass-like consistence, and ina ccrtain Hight resplendent like jelly-fish. They are the shape of a handsome shoe; the edge of the shoe projects in a very ornamental dentated margiu, and the toc part is highly nrnamental, as if witb embroidery insertiou. Mr, M. Latham says: ‘It is a kind of jelly-tisb ; I have had considerable difficulty iu finding ont its real nature. At last I ascertaiued that it is nne of the pteropoda, or wing-footed molluscs.’ The Rev. J. Wned writes: ‘These are so-called from tbe fin-like lohes that project from the sides, and are evidently analogons to the similar organs in some nf the sea snails, These appendages are used almost like wings, the creature flapping its way vigorously through tho water, just as a hutterfly urges its devious course through tbe air, They aro found in the hotter seas, swimming boldly in vast multitudes amid the wide waters, and one species (Clie bereatis) bas long been celebrated as furnishing the huge Greenland whale witb the greater part of its subsistence. Tbe scientilic name of it is cymbulia, so enlled on aceount of its being so like a boat.’ We read : ‘Cuvier describes the cymbulia as baving a cartilaginous or gelatinous envelepe in the form of a boat or slipper, beset witb points in longitudinal rows; and the animal as possessing two great wings, whicb are at once branchiw and fins, and between them on tbe open side, a third smaller lobe, which is three-pointed. The mouth, provided witb two small tentacula, is placed between the wings towards the shut side of the cell, and above are two small eyes. The transparency of the texture permits the internal organs to be distinguished with great facility. The sbell is cartilaginous, translucent, oblong in the form of a slipper, and ontirely covered witb a delicate and scarcely visible membraue.’ “These slippers of tbe Marine Venus are so beautiful in form and structure that I propose, if possible, to have a model of them cut in crystal. In the form of ear-rings they would make very pretty ornaments, as showing chaussure of Cinderella of the ocean.” Astronomical Work in Washington. The editor of the American Manufacturer bas made ‘‘an excursion” to Wasbington and took these notes: ‘‘We visited the Naval Observatory, and saw there several objects of interest. Among them was tbe equatorial telescope, said to be the largest in the world. Itis 32 feet 8 inches in length, with an object glass of 26 inches in diameter, clear aperture It was made by Alvin Clark, of Cambridge, Mass., in 1873, ‘We saw there also the standard astronomical clock whicb keeps tbe time for the Observatory, and#from which Wasbington mean time is telegrapbed every day to all parts of the country. To keep tbis clock from sudden ebanges of temperature it is inclosed by a thick wall nf masonry, and to keep tbe wall free from moisture a coal fire is coustantly kept burning in tbe room. “The records of tbe transit of Venus are being worked up hy the offieers in charge of tbe Observatory. Few have any idea of tbo immense amount of lahor expended in this direction. It includes microscopic measurement of a large number of pbotographs of tbe transit, which have to be made witb expensive and complicated apparatus especially designed for the purpose. Most of this apparatus is entirely novel, and is the invention of Prof. William Harkness, wbo was one of the chief officers of the transit expedition. Tbe cbronometers used by vessels of the navy are all tested and their rate of error recorded at this Observatory. We saw a large number of these instruments, which were made by tbe principal manufacturers of tbis country and Europe, and were told those made hy a certain firm in New York are superior in every respect to tbose of foreign manufacture.” Nornensksoip’s Next Expenrnmon. — For Professor Nordenskjold’s expedition, whicb is to set out from Gothenburg, in Sweden, in June, 1878, a vessel has already been chartered for 150,000 Swedish crowns (about $25,000.) King Oscar has contributed 50,000 crowns from bis personal revenue, but tbe burden of the expense will be borne by the friend and patron of Nordenskjold, a merchant of Gothenburg named Dickson. The ronte of the expedition will be from its starting point to the North Cape, thence eastwardly througb the Polar Sea to and through Behring’s Strait; thence along the eastern and soutbern coasts of Asia, tbrougb the Red Sea, the Suez Canal, and the Mediterranean Sea to the Atlantic Ocean, and return home in the autumn of 1879. This looks like a voyage of general discovery, and if tbe North Pole should be struck, all the better. He can hang the Swedisb flag upon it. Spectrum or Exectric Ladut,—M,. P. Desains finds that the spectra of electric light are very similar to those of the solar rays. They are less extensive, particularly on the side of the violet; but the curves of intensity exbibit but slight differences in the region of greatest heat.