SCIENCE NOTES.

Otago Witness, Issue 3029, 3 April 1912, Page 76

SCIENCE NOTES.

—Belt Slipping. — When a belt has become oil soaked and I will not stay on the machine, a good 'method of cleaning it is as follows:—Coil " the belt loosely in a tub of sufficient size, i and cover with whiting. Be sure that the whiting gets in between the coils of the belt, and it will be only a short time before the whiting will absorb the oil from the leather. It will then only, need to be wiped clean to be ready for further ; service. —Latest Submarine. — The latest experiment in establishing J communication by means of wireless tele- ! graphv between submarines and the body of the fleet to which they arc attached ! have proved so successful that the new submarine which is shortly to be delivered to the Admiralty will be equipped with a. complete installation embodying all the ; most recent improvements. The vessel 1 wi*l not onlv be provided with a wireless i installation, but with two guns discharging ' a shell of a remarkably penetrative charac- ! tor. No other naval Power possesses a vessel of such a novel and formidable type. —Hard Bread and the Teeth. — Investigations on the children in the town of Kotzling, in Bavaria, showed that of those who eat hard bread the percentage i with bad teeth was 6.9; of those who eat both hard and soft bread, 8.2; of those eating only soft bread, 10.5. In the town of Ihringen (Baden), the percentages before j and after the introduction of soft bread ■ were as follows:—In 1894, when only hard j bread was eaten. 12.4 per cent.; in 1897, just after soft bread had been introduced, , 12.9 per cent.; and in 1901, when most of the bread consumed was soft, 20.9 per cent. : —Science Sittings. —Discovery of the Speed of Light.— One of the greatest discoveries of science is due to observation of the eclipses of Jupiter's moons. It was found that when the earth was in the part of its orbit nearest to Jupiter, these eclipses occurred 16 minutes earlier than when it was in the farthermost part; whereas by all rule 3 of astronomy they should have occurred at the same minute each time. It was dej duced from this that light was not instantaneous, and consequently took 16 minutes ! to traverse the diameter of the earth's ' orbit, a distance pi about 200 million miles, \ thus giving to light a velocity of 186,000 miles a second, which was accurately shown later by other experiments. —A Substitute for Steel.— An American named El wood Haynes has discovered a new alloy which is likely to i work a great change in some parts of the industrial world. By means of this alloy manufacturers will be able to make cutlery i without the use of iron or steel—a that has hitherto been impossible of accomplishment. Haynes is, by profession, an automobile manufacturer, who make.* a hobby of chemistry. His discovery is a combination of cobalt and chromium. It is unoxidisable, and retains its lustre under all atmospheric conditions. It will take an edge which will compare favourably with the brst steel, to which it is claimed to bo superior in many respects. The alloy will take a hard polish, and is very pleasing in appearance. Pocket knives and razors have been made from it, and used with remarkable success. Iron has been turned on a lathe with it,» whilst the fruit knives made from it have been found not to tarnish from contact with fruit juice.

—Shaft "Water as Motive Power. — ! There are many mines with wet shafts, at the foot of which the falling water has to be collected and pumped to the surface. That this power can be profitably utilised is shown by the experience of the English Bowhil! Coal Company, who have applied it to ventilate the workings of the lowest seam in one of their nits. To collect the water falling down the downcast shaft, the fcubin •« was cut and a ring was fitted around the shaft. This ring collects the water and guides it into a tank placed in a lodgment made to receive it. The ring and tank are 295 ft above the bottom of "the shaft, so tha.t a working-head of about 295 ft is obtained. A pipe from the tank conveys the water to a Felton wheel of 4ft 6in" diameter. This wheel drives a 60in diameter, double-inlet, sirocco fan. capable of dealing with 60,000 to 90,000 cubic feet cf air per minute at 1 to i in water gauge. Should it be necessury at any time to stop the fan, a by-pass va'.ye is provided to allow the water to be discharged directly into the sump from which the main pump's draw their supply.—-Mining and Engineering World, i —Printing Without Ink. — It is possible that before long newspapers will bo printed without the use of printI ing ink. Even the coloured supplements i are to be printed without ink. A German publication, "Die Welt der Technik," del voted to scientific matters and inventions, credits the discovery of the inkless printing process to an "English inventor. In i the course of some electrical experiments, it I says, he accidentally pressed a coin, which ! had fallen on to the table, and was rolling I off, against a. metallic plate covered with i a piece of paper, and at the same time against an insulated electric line. To his amazement he saw a sepia print of the coin .impressed upon the paper. This happened about 12 years ago. Since then the inventor has followed up this observa- ! tion, and has now developed a process for j printing without printing ink. He uses ! dry paper impregnated with certain chemi--1 c:ils, whose nature is not disclosed. In the j process of printing the paper travels over ! a metal plate, and the type is applied on ! the opposite side, a current of electricity ; passing through the paper. According to ; the particular rneta.l used for the substra- | turn, and according to the mode of irnpregi nation of the paper, a great variety of dif- : ferent colours can be produced, so that i multicolour printing becomes an easy matj ter. Origin of the Thermos Flask. — Engineering, in the course of an article I on "Heat Problems,'' points out that Sir James Dewar was the inventor of the thermos flask. In a recent lecture Sir i James said: —"In low temperature experiI ments very goorl insulation was essential, I arid ho was glad to note that excellent. ! vacuum flasks were now purchasable at 4s ' each ; those lie hid tested, and found quite ' good. 'Yfc« first of these vacuum flasks | bad bei'n exhilHted oa the table of that j institution just 19 yeaj-a ago. Since that I date they had extended »nto every laboraI tory, ai;d almost into every household. At ! the" outset they were very expensive, and

he was disappointed that the manufacture had not been localised in Britain. This arose because he had been unable to find there any glass-worker who would undertake to make them, and his orders, therefore, had to be transferred to another country, where the manufacture was afterwards developed commercially. In his first experiments to diminish heat loss ho had relied upon the use of a high vacuum and highly-polished reflecting surfaces. It had since been found that by filling the vacuum space with powdered charcoal or powdered silica the rate of heat loss was only onethird of what, it was in the case of some vacuum flasks, but the results thus obtainable were not better than could be secured with flasks having reflecting surfaces of silver. Hence so long as glass was used for the flask there was no improvement to bo effected by filling the vacuum space with powders. If, however, satisfactory flasks could, be made out of fused silica, the use of powders might prove advantageous, r.ince with silica very high temperatures could be withstood, and for such silvered I surfaces would be unsuitable. Such flasks might prove of great use, especially as the surfaces could bo coated with nickel, but he fait some doubt, which he learnt was shared by Sir William Crookes. as to whether silica flasks could be made free from fissures. If they could, however, redhot bodies could be isolated in them as easily as liquid air in glass flasks.