SCIENTIFIC MISCELLANY.

Temuka Leader, Issue 2046, 15 May 1890, Page 4

SCIENTIFIC MISCELLANY.

Height oe the Aueoba.. —Interesting particulars concerning recent attempts to measure the height of the aurora have been given to the Boyal Danish Academy by M. Adam Paulsen. At Godthaab, with two theodolites four miles apart, the height of different aurorae was found to range from one-third of a mile to 40 miles ; near Cape Farewell, with a base-line of about three-quarters of a mile, the calculations ranged from one to 10 miles; and at Spitzbergen, with a base of about one-third of a mile, the results were from one-third of a mile to 18 miles. In earlier observations Elogel estimated the height of several aurorae at :from 90. to 310 miles; Eeimann found a height for > one aurora of at least 500 miles, and; JSTordenskjold placed the mean height of aurorae at about 125 miles, while Lemstrom observed aurorae as low as 1000 feet, and Hildebrandson saw them below the clouds. M. Paulsen infers that the aurora only appears at; considerable height in the temperate; zone, while in the auroral zone proper the phenomenon is generally produced in the lower atmosphere.

Electricity Direct Eeom Work. —The accomplishment of a hitherto apparently impossible feat—that of transforming mechanical work directly into electricity—is claimed by Professor Braun, of Tubingen. He winds nickel wire into spirals, and as each spiral is elongated or compressed a current of considerable strength is generated. This is increased by putting a number ©f spirals in circuit. Such positive results have been obtained that the experimenter is hopeful of constructing a useful generator on this principle.

Phosphorescent Infection.—The curious discovery has. been : made that the phosphorescence frequently exhibited by the Crustacea is infectious. A French naturalist, M. Giard, lately traced the phosphorescent light in Talitms, and other crustacaa, to bacteria in the muscles, which showed signs of disease On inoculating healthy individuals the same luminous appearance was produced. The disease runs a regular course, and the Crustacea died in three or four days, the phosphorescence lasting a little after death.

Theory of Hypnotism.—Dr Pinel, of Paris, has found that hypnotic patients obey the phonograph as readily as the living speaker. He, therefore, discards the theory of animal magnetism, and believes that the real cause of the phenomena manifested in the few "sensitives" is a disordered mental state. INDISTBUCTIBI/E LITEKA-TUBE. Fire-proof and time proof books, with leaves and covers of sheets of asbestos, and printing in gold or sliver letters, have been suggested.

Scientific Eaeming-.—The first Agricultural Experiment Station, according to Professor W. O. Atwater, of the United States Department of Agriculture, was established at a little German village near Leipsic, in 1851. In 1856 there were five, in IS6I fifteen, in 1866 thirty and to-day there are more than one hundred experimental stations and kindred stations in the countries of Europe. The first Agricultural Experiment Station in America waß established in Middleton, Ct., in 1875. There were four in operation in 18S0, and in 1887 some seventeen in fourteen States. In the latter year Congress made the enterprise national by an appropriation of 15,000d01. per annum to each of the States and Territories having Agricultural Colleges or Departments of Colleges. This bas ted to increased activity, and there are now forty-six, or, counting branches, fifty-seven Agricultural Experiment Stations in the United States. To support these forty-six stations the National and Stale Ap* propriations for the present year amount to 720,000d01., and over 370 men are employed. Electeic Powee.—The utilisation and distribution of electric power are stated by Mr E. L. Pope to have reached by far the greatest development in Switzerland and the United States. In the; former country electricity is transmitted to considerable distances for large motors. At Soldthurn a mauufaetory of, machine screws is driven by an electric motor ofsohcrse power, which derives its energy from a turbine wheel more than five miles away on a mountain stream. At Derendingen a delaine mill of 36,000 spindles is driven by a pair of electric motors of 280 horse power, operated by a turbine wheel twelve miles distant. ;At Imcerne 120 horse power is similarly carried half a mile, and 250 horsepower a quarter of a mile. In the United States no electric motor of more than 60 horse power is known to Mr Pope, but there are as many as 6000 small motors in use, a favorite size being 10-horse power. It is predicted that in cities electric motors will soon practically supplant the steam engines ot less than 50 horse power. A RemABKABLE TeADE. The abundance of remains of the mammoth is almost incredible. Middendorf reckoned that at least 100 pairs ot tusks had been put upon the market yearly during the last two centuries, and from personal observation Nordenskjold is inclined to" regard the estimate as too small. It thus appears ihat in the recent modern trade the tusks of more than 20,000 of these animals of past ages have i been collected.

A Militaet Novelty.—A vegetable cartridge shell, which is entirely consumed in firing, has been brought out in Prance. The cartridge has scarcely half the weight of one with a metal shell, the cost is considerably less, and the inconvenience of removing the shell after each shot is avoided