The Arkansaw traveler., 1884-07-19
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 SCIENTIFIC MISCELLANY.

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 In India cats are sometimes affaclei by cholera, according to a French as thority, and may communicate the di, ease to man.
 Al recent scientific meeting in Lon don 1t was stated that arsenic, in quar. titles large enough to poison beasss, hs known to find its way through the groun1 into wells fifty feet distant.
 According to Dr. A. Besshaus, th. nettle was former extensively employee in Germany for woven fabrics and its us is being revived. The common stingis, nestle may be made into good yarn, bu ! the Chinese net.le gives the best resuls
 Mons. Haley, a naval lieutenant, sta, toned al Madagascar, states that the sol of that island contains much iron, and that in approaching it the compass under. goes considerable and totally abnorma variations. It is therefore suggested tha: Madagascar may be an enormou. mag. net
 A remarkable phenomenon was vii. messed at Nykoping, in Sweden, just af,er midnight on May i4,h. Streams oiligh, were seen to pass suddenly across tn. northern sky from wes, to east. The first appearance lasted about a minute. and was foll owed by a second one oi much shorter duration. The weather was dull and rainy.
 A committee appointed to investigate the discharge of sewage into the Thames river has reported that liquid entering a, Barking is transported many miles up river in the face of the powerful descend. ing stream of land-water. No one had supposed before that sewage could pol lute the water far above the point of its discharge into rapid river.
 Several officers of the Russian navy have devised scheme for reaching the north pole on sledges from the New Sibe- ria islands, the distance being goo nauti- cal miles. The sledge parties would pro- ceed slowly northward, leaving stores of provisions along the route, to ensure the expedition's safe return. The scheme is to be submitted 10 the learned societies of Russia.
 Two French chemists have investigated the question of the temperature at which various explosive mixtures of gas and air become ignited. They found that mix ture of seventy parts of air and thirty parts of hydrogen gas ignited at tem- perature between ioe6 and 1928 degrees Fahrenheit while the ignition point of mixture of coal gas with an air in similar proportions varied from TO, to I2I, de- grees.
 The Law of Survival.-Grant Allen thinks it improbable that as is often sup posed, the extinction of species has been caused by violent destruction by preying creatures, except in those cases where man has been the destroyer. He believes, instead, that most extinct animal and plant forms have really been extermi- mated by the severe competition of other closely-allied forms adapted to fill exactly the same place in nature. As an instance, he mentions the black rat of England, which was once most numerous, but which seems to have been completely starved out of existence by the superior energy of the brown rat in seeking the same sources of food.
 The Lands of the Meter.-A table pre- pared by the librarian of the Paris Geo. graphical society shows that the metric system of weights and measures is now legally obligatory in the Argentine Re public, Austria-Hungary, Belgium, Bo- livia Brazil, Chili, Columbia, Denmark, Equador, France and colonies, Germany, Greece, Italy, Mexico, Netherlands, Nor way, Paraguay, Peru. Portugal, Roumania, Spain, Sweden, and Switzerland, with a total population of ,4I.973oII. is op- honal in Canada, Great Britain, Ireland, United States, and Persia, with popula- tion of o7 ,o5o,S2s. Without having legal value. ii is often used in Egypt, India. Russia, Turkey, Uruguay, and venezuela, having a population of 333.166, ,3S6.
 A Vegetable Wonder banyan tree is forest in itself giving shelter and shade to whole villages of huts. Its vide spreading branches are supported by many separate stems or trunks, formed by descending aerial roots which on reaching the ground become fixed as props to the great leafy roof above. Natives of parts of India regard the tree