Democratic Sentinel, Volume 11, Number 38, Rensselaer, Jasper County, 14 October 1887 — SCIENTIFIC MISCELLANE. [ARTICLE]

SCIENTIFIC MISCELLANE.

Am electric signal apparatus on a French railway causes the blowing of a steam whistle upon a locomotive ap Broaching a danger signal. The engiaeei te thus warned. This apparatus is found valuable in fogs and snow-storms, when ordinary signals often escape notice. The number of varieties of insects is vastly greater than that of all other living creatures. The oak supports 450 Species of insects, and 200 are found in the pine. Humboldt, in 1849, calculated that between 150,000 and 170,000 species were preserved in collections, but recent estimates place 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 cemeteries is reported to be indistinguishable from that of arable lauds. Concerning the moon’s effect on tides, the Astronomer Royal for Ireland recently stated that, while the day is gradually lengthening through lunar action tides, the earth reacts on the moon 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 50,000,900 of years ago—the two bodies Eust have been very close together, lien the day was but three hours long instead of twenty-four. At that diatant period, the earth rotated once every three hours, and the moon revolved with it in the same time. Bo near was the moon That, if there had been oceans in those da vs as now, the tides must have been Bio times as great as at the present time: and, rising to an immense height, would have swept over the whole of England.

Andul life in the Sahara is somewhat peculiar to the region, and, according to M. Vogt, the traveler is struck with the Absence of all bright colors in the animals of the desert. As a rule, their hue S proaches that of the ground, and the aptation is most remarkable in birds, reptiles, grasshoppers, etc. Black ana white exist in some animals—for laitance, the male ostrich—which have nothing to fear from enemies; and a dngle exception to the rule occurs iwnong insects the Coleop tera are ttearly.all black. To explain the existence in safety of these insects whose solor must make them conspicuous, M, Vogt states that they feign death on the tpproaoh of danger and in that state Blosely resemble the excrements of gazelles, goats, gnd sheep. This description, with their disagreeable odor, gives them Shffioient protection. The general color of the ground to the desert ■, of course that of sand.

At the Crystal Palace, London, a lecond international electrical exhibition IB to follow closely on the heels of the ■rat at Paris. The objects to be exhibited are chiefly compared in these tiasses : Apparatus used for the production and transmission of electricity ■nd magnets, natural and artificial ', mariners’ compasses; lightning conduo tors, and applications of electricity te telegraphy and the transmission of •ounds, to the production of heat, to lighting and the production of light, to the service of light-houses and signals, te apparatus giving warning to mines, failways and navigation, to military art to fip9 arte, to electro-chemistry ana ohemical arts, to the production and transmission of motive power, the meahanical arts, to surgery and medicine, to hoxtlogy, to astronomy, to meteorology, io geodesy, to agriculture, to apparatus for registering, and to domestie uaes. It is expected that the exhibitiua <ill prove much -ore attractive V imwdoans iLu. thas at Paris,