Democratic Sentinel, Volume 8, Number 6, Rensselaer, Jasper County, 7 March 1884 — SCIENTIFIC MUSCELLANY. [ARTICLE]

SCIENTIFIC MUSCELLANY.

Ax «leetrie iigmi apparatus on a DnmA railway aaaaea the Mowing of a •team whistle upon a locomotive approaching a danger signal. The engineer H thus warned.'' This apparatus is found valuable in fogs and snow-storms, when ordinary signals often esoape notice. The number of varieties of insects is vastly greater than that of all other living creatures. The oak supports 460 species of insects, and 800 are found in the pine. Humboldt, in 1849, calculate* : that between 150,000 and 170,000 species were preserved in collections, but recent estimates piaoe the present number at about 750,000 species. It is a very general belief that great burial places exert a noxious influence, which must render the localities very unhealthy as places of residence. This idea is shown to be a mistaken one by the results of any inquiry into the sanitary condition of the cemeteries of Paris. The composition of the air in the cemo- ■ teries is reported to be indistinguishable from that of arable lands. Concebning the moon’s effect on tides, the Astronomer Royal for Ireland receutlv stated that, while the day is gradually lengthening through lunar action tides, the earth reacts on the muon and drives it away farther and farther. Looking backward, the moon must have been nearer and nearer the earth, and at one epoch in the remote ages of the past—perhaps about 50,000,000 of years ago—the two bodies must have been very close together. Then the day was but three hours long instead of twenty-four. At that distant period, the earth rotated once every three hours, and the moon revolved with it in the same time. So near was the moon that, if there had been oceans in those lays as now, the tides must have been 216 times as great as at the present time; ind, rising to an immense height, would have swept over the whole of England. Actual life in the Sahara is somewhat oeculiar to the region, and, according to Vl. Vogt, the traveler is struck with the ibsence of all bright colors in the animals of the desert. As a rule, their hue approaches that of the ground, and the Captation is most remarkable in birds, reptiles, grasshoppers, etc. Black and white exist in some animals—for indance, the male ostrich—which have lothing to fear from enemies; and a angle exception to the rule occurs imong insects the Coleoptera are learly all biaclc. To explain the existmce in safety of these insects whoso '-olor must make them conspicuous, M. ! \fogt states that they feign death on the | ipproach of danger and ip that state* ;losely resemble the excrements of . jazelles, goats, and sheep. This de- ; ioription, with their disagreeable odor, jives them sufficient protection. The general color of the ground to the desert s, of course that of sand. At the Crystal Palace, London, a ! second international electrical exhibition s to follow closely on the heels of the irst at Paris. The objects to oe exhibted are chiefly compared l iu these lasses : Apparatus use i for the producion and transmission of electricity md magnets, natural and artificial; aariners’ compasses ; lightning ooudno ors, and applications of electricity u> elegrapliy and the transmission of rounds, to the production of heat, to lghting and the production of light, to .he service of light-houses and signals, o apparatus giving warning to mines, •ailways and navigation, to military art, o fine arts, to electro-chemistry and •hemical arts, to the production and ransmission of motive power, the mehanical arts, to surgery and mediein*-. o horology, to astronomy, to meteoro 1 - gy,‘to geodesy, to agriculture, to :u>>aratusfor registering, and to dorm m .*• ises. It is expected that th'> exh.V : dll prove mn.-h more atuu t.v. , .Americans than that at Paris. A Pennsylvania man who was clawed ■y a wildcat says that the feeling was * anything like having a dozen buzztiwa loose on him for a high old me. Upon reptiles the fluid Secreted in the iead of the toad acts as a powerful inimt. On man it produces no effect be ond a slight local irritation.