Democratic Sentinel, Volume 17, Number 7, Rensselaer, Jasper County, 3 March 1893 — POPULAR SCIENCE NOTES. [ARTICLE]

POPULAR SCIENCE NOTES.

Electricity in Agriculture.—Electricity has been successfully applied in agricultural operations at tho Polytechnic Institute of Alabama, at which pluoc a motor has been at work siuce last spring threshing oats, wheat, rye and barley, cutting ensilage, grinding corn and ginning and pressing cottou. And this, writes Franklin L. Pone, in the current number of tho Engineering' Magazine, is going on in a State where less than fifty years ago hundreds of miles ol telegraph lines were destroyed by a mob of farmers, because the wires wore supposed to have superinduced a distressing drought which occurred shortly uftei their erection. Verily, the world moves. Silk From Wood Pulp. —A revival of interest is noted in the attempts started some years ago, particularly in France, to manufacture silk from wood pulp, nnd by methods, as proposed by M. Chiml(inner, similar in principle to that employed for converting wood into paper. It is well known that, a few years ago, large works were built at Besadcon, and preparations for manufacturing silk in this way were projected and carried out on a somewhat extensive scale; the result was that, though remarkably satisfactory specimens or si|k made by the process in question were shown, it was found that the fabric so manufactured could not be woven successfully in large pieces, and that it was of so highly inflammable a nature as to be a source of great danger. To overcome these difficulties very thorough experiments have for some time past been under way, and with such results that the company having the industry in charge claim to be able to furnish a substitute for silk possessing all the essential qualities characterizing that article, and which is expeoted to be put upon the market at about one-half the cost of tho genuine article, dress pieces, ribbons, etc., being included inthepiospective goods. Sounds We May Not Hear.—Animals may bear sounds that are inaudible to us. Certainly the sounds that give the keenest pleasure to many animals—cats, for example —are seldom capable of giving pleasure to us. We know, of course, tnat sounds may be too low or too high—that is, the vibrations may be too slow or too rapid—to be audible to the human ear; but it does not follow that they are equally inaudible to differ-ently-tuned cars. The limits of audible souud are not invariable even in the human ear: women can usually hear higher sounds than men, and the two ears are not, os a rule, equally keen. A sound may be quite inaudible to one person and plainly heard by another. Prof. Lloya-Morgan mentions as an instance of this a case in which the piping of some frogs in Africa was so loud to him as almost to drown his friend’s voice, but of which his friend heard absolutely nothing! The same thing may be observed by any one possessing the little instrument known as Gallon’s whistle. The sound made by this whistle can be made more and more shrill, until as last it ceases to be heard at all by most persons. Some Can still hear it; but by raising the sound still higher even they cease to hear. The sound is still being made—that is, the whistle is causit}g the air still to vibrate, but so rapidly that our ears no longer recognize it, though the existence of these inaudible vibrations is detected by a ‘sensitive flame,” as was first shown by Prof. Barrett in 1877. —[Chamber's Journal.

It is computed that all the locomotives in the United Btates would, if ooupled together, make a train 300 miles long. The passenger cars would make another train of about the same length, and if all the cars of every variety in the country were coupled behind the enginea, the result would be a train just about 7,000 mflai long.