Science Siftings

New Zealand Tablet, 26 July 1906, Page 35

Science Siftings

By -Volt'

Peculiar Action of Water. Metal does not rust in Lake Titacaca, South America- A chain, an anchor, or any article of iron, if thrown in this lake and allowed to remain for weeks or months, is as blight when taken up as when it came fresh from the foundry. Combination in Metals. A combination of copper and zinc makes bell'metal, a variety of bronze of which bells are made. A combination of tin and copper nia^es bronze metal, with, a preponderance of copper. A combination of tin, antimony, copper, ami bismuth makes britannia metal. A combination of tin and copper makes cannun metal. 'A combination of copper and zinc makes Dutch gold. A combination of copper, nickel, and zinc, wilh sometimes a little iron and tin, males German siher. A combination of gold and copper makes standard gold. A combination of gold, copper, and siher makes old standard gold. A combination of tin and copper makes gun metal. A combination of copper and zinc maVcs mosaic gold. A combination of lead and a little arsenic makes sheet metal. A coniftination of silver and copper makes standard silver. A combination of tin and lead makes solder. A combination of lead and antimony makes type metal. A combination of copper and arsenic makts white copper. A combination of tin and lead makes j.ewter. Glass-making Invention. A consular report from Nuremberg, recently issued, gives details of a new in%enticn in the glass-plate industry, which, if it does all that is claimed for it, will seriously affect the blowing glass-plate industry. The new method is the invention of Mr. Fourcault, a Belgian, who has sold his patent to a European syndicate of plate-glass manufacturers for £190,400. This syndicate consists of German, French, and Belgian manufacturers, and one Bohemian factory. Up to the present in the making of window glass the molten substance has been blown into cylinders by glass-makers' pipes and subsequently flattened, while in the making of plate-iglass the viscid mass was cast fiom the pots and rolled. The new invention draws the molten substance from the pot and conducts it between rollers lying side by side. Seventeen pairs of these rollers are built up towerlike above the pot. The liquid cools on its way between the rows of rollers, and comes out from them polished on both sides, in any desired thickness (this being regulated by the relathe position of the rollers), beautifully flattened and ready for use. It is believed that this invention will bring about a revolution in the trade. How Nature Tales Co\cr. In an interesting lecture on ' How Nature Takes Cover,' in Wellington recently, Professor Kirk showed butterflies resembling green or faded leaves so perfectly, even, to- details of venation, that not only their enemies, the birds, "but even human eyes might be deceived. Even the wings had narrow pi ejections at the hip so that when they were folded and the insect perched on a twig it seemed to be attacked by a footstalk. Perfectly harmless flies in some Cases so strongly resembled bees, wasps, or other stinging creatjures that birds left them in peac,\ Caterpillars simulated buds, and even had the habit of resting standing on end at the proper angle to the branch. Ihe New Zealand ' walking stick ' was well known, the lecturer stated. lie showed a number of living examples on a native plant. As an example of the effect ii <c mimicry of these curious creatures, Professor Kirk said that, thouph he Knew that there were fifteen on the plant from which he had taken them he oould only discover three in the course of a long search. He explained the accepted theory regarding the evolution of these remarkable adaptations, that in the course of ages the elimination by natural enemies of the * unfit, particularly the conspicuous, left only those possessing exceptionally deceptive qualities to carry on. the succession, and that the type was modified accordingly. He remarked that human intelligence had been slow t 0 take the hint from animal instinct. The lion and tigec wore the livery of the jungle, but until lately men went forth to war in the brightest and most conspicuous