Science Siftings

New Zealand Tablet, 27 March 1913, Page 49

Science Siftings

By 'Volt.'

Nature's Alchemy. In a recent address. Dr. W. S. Lazarus-Barlow said that the story of radium is one of nature's masterpieces of satire. The alchemists spent lifetimes in trying to change base metals into goid, when 'for untold eons nature has already been turning a relatively common metal, uranium, into radium, 170,000 times as costly as goid. The alchemists' wildest dream was more than fulfilled ; but at the same time nature was endowing radium itself with the property of ceaseless change, and, according to some, decreeing that the transmutation should proceed until the radium became converted into lead —worth a few pennies a pound. It is true that it would take an ounce of radium 2000 years to form half an ounce of lead, but this only makes the satire more striking, for we first learned of the existence of radium when of lead there was enough and to spare.' A Wholesome Food. With the increasing demand for fresh fruits at all seasons of the year has come the difficulty of supplying them in a condition in which the dangers of contamination are largely averted. Decay is one of the limiting factors in the use of fresh fruits. Among the many fruits there is one (the banana) which is equipped in its native form with a protective covering that calls for more than passing mention. The banana consists, in its green state, largely of starch and water. The essential change during the process of ripening is a conversion, of the starch into sugar. The rate of ripening is dependent on the temperature. The edible portion of each fruit is packed away in a peel which serves a more useful purpose than has hitherto been realised. Experiments on the fruit in different stages show that the inner portions of the pulp of sound bananas are practically sterile. The peel is singularly resistant to invasion by bacteria. Even when bananas were immersed in fluids containing disease germs they did not penetrate into the interior. This is an interesting example of a food delivered by nature in practically sterile packages. Light Without Heat. M. Dussaud, a French scientist, has discovered a means for the production of what he terms ' cold light,' made public some details of his discovery, which it is thought may revolutionise electric lighting. Starting on the principle that rest is as essential to matter as to animal organism, he has constructed an electric lamp in which the light is concentrated on a single point by filaments working successively; thence the light is projected through a lens magnifying a thousandfold. Thus he has succeeded in concentrating a 2000candlepower light on one point and in passing 32 volts into an eight-volt lamp, which with the ordinary light would burst. Experiments with this lamp have established that the new light is absolutely without danger, as no heat is given off, and it requires 100 times less current than the ordinary lamp. It can be worked by a tiny battery, or sufficient motive power can be obtained from a jet of water from an ordinary faucet. Invisibility of Icebergs. The invisibility of icebergs at night, is interestingly discussed in a recent bulletin of the United States Hydrographic Office. Dr. Abbott H. Thayer, the author, :. , contends that on a clear, moonless night and often on (' a moonlit night, a steamer might run very close upon an iceberg without the slightest sight of it. It is a matter of easy observation that it is the most nearly horizontal top surfaces of a berg, the snowy roof, or other white object that receive the most skylight, and in consequence most closely match it. It 1 follows that with the average silltop shape of an iceberg it will be the highest expanses that are surest to be indistinguishable. These expanses constitute the contour that the watch would espy, were the berg visible, and with these effaced, the berg is optically as if it were not.