Science Siftings

New Zealand Tablet, Volume XXXIV, Issue 5, 1 February 1906, Page 29

Science Siftings

By 'Volt'

The Eyes of Animals. Many animals possess more than two eyes, which do not act together. A leech, for example, has ten eyes on the top of its head which do not work in concert, and a kind of marine worm has two eyes) on the head and a row 'down each side of the body. Some lizards have an extra eye on the top of the head which does not act with the other two. A bee or wasp has two large compound eyes which possibly help each other and are used for near vision, and also three little simple eyes on the top of the head which are employed for seeing things a long way off. Silk and Twine from Smokeless Powder. Silk and twine are now being made by the military authorities in various countries trom smokeless gunpowder. Smokeless powder is a nitro-cellulose compound, and its basis is guncotton ; it can be made glutinous, so as to be squeezed through fine holes in a metal plate, producing threads after the manner of artificial silk. These gunpowder threads are woven into silk for holding! the powder when placed in the gun, and also into ,twine for fastening the necks of the bags. When the charge is fired nothing remains of the bag. How Sea Birds Quench Their Thirst. The question is often asked, ' Where do sea birds obtain fresh water to slake their thirst ? ' but it has never been satisfactorily answered until recently. An old skipper has tola how he has seen these birdis at sea, far from any land that could furnish them with fresh water, hovering under a storm-cloud, clattering like ducks on a,- hot Hay, at a pond, and drinking in the drops of rain 'as they iell. They will smell a rain-squall when a hundred miles away, or even further, and fly towards it with almost inconceivable swiftness. Plow long sea birds can exist without water is a matter of conjecture, but probably their powers of enduring thirst are increased by habit, and possibly they go without water for many days, if not lor several weeks. The Sea-Serpent. Nature sometimes plays strange pranks. What scientist, for instance, reasoning along orthodox lines, could have dreamed of the existence of seals in Lake Baikal, in. Central Asia, a thousand miles- and more from the sea. Yet there they are (says ' T.A.T.'), proving, beyond the possibility of a doubt, that once upon a time that great fresh-water lake must have been connected with the open ocean. Similarly, the fossil remains of whales found around Lake Nyanza show that the great Central African rift extended to the salt sea after a like fashion. And in this connection it is noteworthy that only within recent years has the existence of seals in Lake Baikal been certainly proved. Their presence there, although always insisted upon by the natives, was regarded m the nature of a legend. Yet the lake is but a puddle compared with the limitless waters wherein the sea-serpent is said to disport itseli. Everyone is familiar with the arguments for the existence of this monster ; how, lor instance, the vast expanse of ocean, which coxers three- quarters of the globe, is, after all, a weil-ingh unknown waste, only crossed in comparatively few directions by established oceanlanes that can be easily avoided. And its depths are abysmal. Who shall dare say what strange beings lurk therein. Why, until the ' Challenger ' expedition, the existence of what are now known as the deep-sea fishes was quite unsuspected. ' How is it possible/ scientists argued, ' for highly organised creatures like fashes to exist amidst total darkness, in a temperature for the most part. at or below freezuigl point, 'alid isubjfect to a pressure per square inch that can be reckoned in tons ? '