Scientific and Useful.

Lake Wakatip Mail, Issue 1517, 29 January 1886, Page 4

Scientific and Useful.

THI VITAL or THE VtTTCBI. An American paper says that the metal of the future is aluminum, and that in a few years it will displace iron and steel and revolutionize the induatrial arte. It says the world contains ten times as much of it aa of iron—r very clay bed being an aluminum mine. It ii three times stronger than Beaaemer steel, will not corroda. is very ductile, is a third lighter thin cast-iron, and the raw materials for making it are not worth S2O a ton. ARCTIC IHBEr. Lieut. Oreely, lecturing recently before an agricultural society in Massachu'etts, said that during his Arctic journevs he had die- | rorere I flicks of aheep with large heads, horns like oxen, and tails resembling those of horses. Their fleece ia of the finest and thickest wool, almost eurpasaing that of the merino, lie suggestel that as in New England sheep j were freqnen'ly lost during severe winters, it i would be worth while to make an experiment in a'-c'imatising the Polar aheep. rrRIFTINO AIR BY WASHING. M. Windhausen has designed an apparatus for the purifying of air from duat, germs, and other impurities, which i* well spoken of by French technical writers. The principle of the appliance ia to impart a rotatory movement to the air to be purified ; the air being ;at the same time surrounded by a surface of water in movement. The idea is that in this w»y the solid impuritiea whioh may happen to be in the air will be thrown, by centrifugal force, against the water surface; and .they will consequently be taken up and caaried away by it. BLKPI!fG lISHES. An experiment has recently been tried at the Inventiona Exhibition Aquarium by Mr W. August Carter, with a view to discover how far fish are prone to sleep. After a close examination, he found that amongst freshwater fishes the roach, dace, gudgeon, carp, tench, minnow, and cat-fish sleep periodically in common wih terrestrial animals. The same instincts were found to actuate marine fish, of which the following were observed to j be equally influenced by somnolence —viz., the wrasse, confer eel, dory, dog fish, wrasse bass, j and all species of flat fish. Mr Carter states that, so far as he can discover, the goldfish, pike, and aDgler fish never sleep, but rest periodically. Desire foi sleep amongst fish varies according to meteorological onditions. Fish do not necessarily select night-time for repose. A 6CKXEK FOREST. It is said by fishermen who ply their avo- I cation otr Kenosha that a f orest of considerable dimensons exists in the bottom of Lake Michigan, about five miles distant from the city. B>me years ago it was the custom with the fishermen of the place to cast their nets nearer shore, but aa the fish gradually became less plentiful the fishermen mo\.' further! out, until they encountered the forest of trees mentioned, and it effectually stopped them from using their no's there. Repeated ex- I perimen's fixed the further boundary line of the timber something near twenty miles from shore, to which distance they now go to cist their nets. It is stated that trees hive been known to wash ashore that have evidence of having remuined under water for centuries. They were in a perfect state of preservation at first, but rery soon decayed after exposure to the atmosphere. The wood, too, was of a kind entirely unknown in the country or anywhere on the lake. DISPIBSIOX or SEEDS. Some very advauced plants go so far as actually to disseminate thair own seeds, or even to bury them bodily under ground. There is a common little English weed, the wall cress, abundant everywhere on banks and in dry places, whose pods, especially when touched or shaken, roll up elastically, and | scatter the tiny, bullet-like seeds to a distance ! of some six or seven feet by their powerful j impulse. The capsules of the balsam similarly eject the seeds for a considerable length, 1 and everyone must have noticed the crack*! ling of the gorse-poda on bright autumn days, i by which mean* the small beans within are ' thrown out forcibly with no little violence I among the surrounding thickets. The squirting cucumber of Southern Europe, if lightlv touched when quite ripe, breaks off at the stalk with a slight bang, and scatters its seeds and their surrounding pulp not infrequently in the face and eyes of the too-intrusive visitor, j More remarkable still is the plan adopted by ! the subterranean clover, in which the un- j developed fljwers in the centre of each head act as a sjrt of insinuating cork-screw, and, screwing downwards, bury the pods of the fertile blossoms at last far beneath the surface of the close cropped turf. In the faailiar pea-nut of American youth the same cunning device is ca ritd to a still further pitch of perfection with Yankee ingenuity ; for the socalled nuts are really subterranean pods, produced by aelf-fertilization upon simple budlike underground flowers, and therefore, as it were, ante-natally buried. In these laat cases the object is, no doubt, rather to escape the notice uf enemies than to ensure dissemination in the ordinary sense, for mere purposes of ro'ation or dispersal.—Grant Allan, in Kno>rl'dge.

DECAY O* THE " MBDLEi."

Cleopatra's Needle, the Egyptian obelisk at Central Park, New York, is found to be rapidlv crumbling (away under the influence of our Anwrican climate. For 4000 years the needle suffered comparatively little change in the dry warm air of Etfypt, but though it has been in America only five years there are already unmistakeuble sign# of i's serious decay. Fragmerits of rtone are found scattered at the base of the needle, and flakes an inch or more in length can readily be picked cff with the fingers On the eastern side of the monolith there is a tissuro three feet in length and sufficiently wide to admit the insertion of a knife blade for a distance of two or three inches. A finer crevice extends to a much greater depth. The vein containing the fissure can be traced to the south and west sides. Should this large fragment split off, the obelisk would undoubtedly fall. These indications lure led the Park Board to consider means for its artificial preservation. Professor Doremus strongly recommends the use of paraffin, which is not affected by the atmosphere and has the advantage of being impervious to moisture. The stone would be warmed at its surfacd in order that it should absorb the melted paraffin more readily. This treatment would make the stone somewhat darker, but brighter and nearer the colour of the original syenite. It is .thought that it would prevent further decay. The corresponding needle, erected on the Thames Embankment, Lond >n, has undergone a similar deterioration and artificial protection was fouud necessary. In this case a liquid was used composed of a solution of dammar resin in a volatile hydrocarbon, with a small quantity of wax and a still smaller quantity of corrosive sublimate added. Prof. Brookes the great English chemist, is, however, quoted as preferring paraffin to dammar retin.— BcintjflQ Ammetn.