Science Siftings

New Zealand Tablet, Volume XXXVI, Issue 13, 2 April 1908, Page 35

Science Siftings

Coal Tar Colors. The recent celebration of the jubilee of the coal tax . dyes must have made the heart of the colorist recoil. Fifty years, then, have we had the most shocking colors with which ingenious man has sta ned l'inei} and goltien silk—fifty, y^ears af arrant mauve and. hard magenta,- and the color called- after another battle of the fifties, something redder than "majenta, a solfeiino, to set the teeth on edge— for though William Morris tried to suppress these hideous hues by the reintroduction of vegetable dyes, soft and lasting, and though the aesthetic fashion of the seventies and eighties overca/me the aniline colors for a time, they soon again came uppermost, and we have them now, strong and as hard as nails. The Growth of Rocks. Rocks do not grow in the sense that plants do." They may increase in size by means of accretion, and they may also undergo other changes. Old sea beds lifted up and exposed for ages become stratified beds of sandstone or limestone ; volcanic ashes - and lava strewn over hills and plains become tufa, hard enough for building stone, and the pebbly shores of rivers and ■ smaller streams may sometimes change into conglomerates. The simple mineral, however, does grow, especially when it takes upon itself the form of a crystal. A sparkling prism of quartz increases from an atom to monster crystals of varying leng-th and size by what geologists know as a ' process of addition and assimilaticm.' This process is wonderfully slow, but with a mathematical exactness that is a surprise to persons even ' well up ' in the science of geology. In one sense, stones grow ; in another, they do not. The crystal may become longer and larger, but the boulder on the roadside will not increase a hairbreadth in fengith or width in the next 10,000 years. Use for White Mice. _x White^mice have attained to the dignity of a place on one of the -flags of the Royal Navy. The flag on which they appear has been designed for use by the submarine boats. They appear in a shield above a Latin motto. The first and fourth quarters contain representations of a submarine and three torpedoes, while the second and third enclose a white mouse rampant. It s very appropriate that this timid little creature should be so honored, as on every submarine boat several are kept. They are particularly sensitive to dangerous gases and soon show by their appearance whether any petrol fumes are escaping from the tanks. The sailors keep a close watch on them 1 , and on the slightest sigoi of exhaustion a diligent search is made for the leakage, and measures • are taken to remedy the defect. White mice have also been carried by rescue parties going into mines after explosions, for as long as they keep lively it is. safe for the men to proceed. The Conquest of the Air. There can be no doubt (says the ' Freeman's Journal') that M. Henri Farman, has at long, last gone far towards the conquest of the air. He certainly outdistanced the feats of all rivals by his flight, or flycall it what you will— for the Deutsch-Archdeacon Prize of £2000. Before starting- for the test M. Farman had made practically oertain of success, for . he had accomplished a flight of over a mile. This was beyond all comparison the greatest thing in flying man had 'done as yet in the whole history of the world. In the actual test the aeroplane behaved splendidly. It proved perfectly dirigible. Going along and obeying! the helm perfectly at a height of 25 feet, It negotiated all the posts which marked off the course, and at the end of a spin of - 1630 English yards was brought easily and gracefully to Mother Earth again. The result marks an epoch in the history of invention—in the history of the human race. Man has now, as it might be put, accompanied the birds on the wing for a distance of a mile, going all the time at the rate of 25£ miles an hour. No longer is the perfect aeroplane 'a mere dre a m, a dangerous, toy. There is really no setting of limits to what man may now soon accomplish overhead. A cable message -received last week from Paris stated that Mr. Farfnan travelled a mile and a half in his aeroplane at a height of six metres (about 20ft). After making three circuits he gently descended. _