SCIENCE AND INVENTIONS.

New Zealand Herald, Volume LII, Issue 15912, 8 May 1915, Page 4 (Supplement)

SCIENCE AND INVENTIONS.

COLOUR OF MILK.

Recent experiments show that the colour of milk is chiefly duo to the presence of carotin, a colouring matter found abundantly in green plants, especially in grass. The yellow pigments of our bodies also consist of carotin, which is probably derived chiefly horn our food. THE DISCOVERER OF ALUMINIUM. Aluminium, one of the most abundant and widely distributed of all the metals, was little more than a laboratory utmostity until, in 1886. Charles Martin Hall. then a young man of 22. discovered a cheap way to reduce it. When he had made his experiments aluminium cost as much as silver. Doctor Hall died last month. tew. people ever heard of him, yet his m hievemrnt is one of the most notable in American si lentifit history.

IRON V COPPER WIRE. Lecarse large ouantities of copper are used in the manufacture of ammunition for the German hi my and because flic war has restricted the import of that metal, the German Association of Electrical Engineers has Issued an announcement recommending ihe use of iron wire instead of copper •rln'.evcr possible. The substitution tan i-aJily be carried out in direct current installation, but where alternating current is used, it introduces complications because of the skin effect and the increased impedance.

A N ISSING CONTINENT. News has come through the Bulletin oF the American Geographical Society that the Arctic expedition under Professor I). M. Mac.Milhcn has failed to Hud the land which Admiral Peaty thought he sighted in 1906. far to the north-west of Grant Land, and which has since figured on tho naps under the name of Crocker Land. 'the expedition sailed in 1913 and established its bi.se at Ktnh, on the north-west coast of Greenland. The journey to Grant Land, and thence over the ice of the Polar Ocean in the direction in which Crocker Laud was supposed to lie. was earned out in the. spring of last year. The explorers, like Admiral Peary, in 1906, saw in the distance the appearance of new land. As they advanced, however, it vanished from view, and at last they were driven to the conclusion that they had been deceived by a mirage. After advancing about 125 miles over the ice without finding or even sighting land, they turned back. The expedition will remain engaged in exp'oring and scientific wo-k ill north-west Greenland and the adjacent lauds for another year.

GERMAN BOMBS AND FRENCH BULLETS. There is no doubt that Parisians have at times been greatly alarmed about acrid raids. Recently. Prof. H. I.c Chateiicr gave an addles* on the subject. Ho mentioned that Button, in a little work full of subtlety. entitled. " 1/Arithmotique Morale." several ctfnturics ago called the attention of his healthy readers to the fact that each of them had one cliar.ee in thirty thousand of being dead before the end of the day. The 'laubes have killed about one Frenchman in three hu dred thousand in Paris, not in <jie day. be it understood, but since the beginning of the warthat is to say, at the. date of the lecture, in one hundred days. Thus they increased each Parisian's probability ol death by one-thousa'nth part of what it had been before. Wis it worth worrying over?" asked the lecturer. "Let us now sift scientifically.'' said lie, " the means adopted to combat' this danger. Rifles and mitrailleuses have been put into uctiom. Now. every bullet tired into the air falls back—the laws of gravity teach us that for certain—with a speed in the neighbourhood of two hundred meters per second: that is to say, with the speed of a revolver bullet; consequently sufliciemt to kill a man. So the number killed by French bullets must have exceeded the number slain by Germnnt- bombs. Elementary scientific reasoning would have prevented this accident."

AX AEROPLANE INVENTION. In carrying out scouting observations with military aeroplanes it. is essential that there be two men in the machine, namely, a pilot whose sole duty it is to operate and steer the craft, and an observer who can devote undivided attention to scanning the ground below him and making sketches of fortified works, the disposition of the enemy's guns, the movements of their troops, and the like. Unfortunately, the great noise made by the motor renders it impossible for the two men to carry on any conversation. Often this proves quite a drawback for a proper understanding between pilot and observer. To remedy this defect a loudspeaking telephone system is now in use between pilot and observer in some of the military aeroplanes. Kadi man is provided with a special helmet fitted with receivers over the ears and a transmitter located in convenient rango of the mouth. This has proved to be a most practical way of keening tip a conversation in spite of the deafening noise of the motor. A still further improvement has now been made If the observer is to make sketches of the ground over which he is Hying, he will be so much occupied, probably, as not to have time to jot down note's. Sometimes events may follow in such rapid sequence that he may not have time to write down all he would like to. In certain conditions .of flight, it might be difficult to use pencil and paper. In order to remove all obstacles that might hampeiythe' observer's work, a phonograph is now provided, with a speaking tube running to the observer's mouth, so that he may talk into the machine at any time during the fight and thus make a record of his observations, while at tho same time his hands are free for the uso of field glasses or the sketching pencil. At the end of the flight the phonograph delivers its message.

MARIN SKiNAf.T.INf; APPARATUS,

There is a new marine signalling apparatus which will, it is believed, diminish sea disasters. It consists of an electric oscillator which announces tho present'' of another vessel, locates icebergs, indicates sen depths, and provides for ib'' transmission of submarine telephone and telegraph messages. The device consists principally of a 24m metal diaphragm attached to a cylindrical case, within which is an electro-magnet actuating a copper sounder. The oscillators, when in permanent position, are placed inside of a ship's skin, beneath the waterline, or, both the port and starboard sides. Vibrations of the diaphragm amounting to a movement of one-thou-sandth part of an inch and repeated with great rapidity throw out sound waves under the water which may be caught by the receiving apparatus on another vessel Signals of this kind have been heard at a distance of 30 miles, while at shorter ranges numerous telegraphic conversations have been carried on successfully- In one instance the experimenters actually talked between two ships. In locating iceberg l it is the echo which gives warning ol the presence of danger. With a stop-watch it is possible to estimate quite accurately the distance of these harriers, this being accomplished in one instance, after the steam whistle on a revenue cutter had failed to obtain an echo when within 150 yds of a berg. While the foghorn has been of certain assistance to the mariner if also has been an instrument which has terrified him. It has 'old him that he was near danger, but rarely whether he was headed for it or running from it, because the air currents made it impossible to determine absolutely whether tho sound was coming from one direction or from another. The oscillator sending its vibrations through the water eliminates this. By Listening from both sides of a ship it is 1 easy to determine from what direction the strongest sound is coming, and it then is possible to turn immediately away from, for instance, the course of an an". [preaching sxeamer,