SCIENCE NOTES.

Digger (Invercargill RSA), Issue 19, 23 July 1920, Page 14

SCIENCE NOTES.

FIREPROOF PAINT. There has recently been placed on the market a form of paint, two coats of which applied to woodwork, render it, for all practical purposes, non-infiammable. It can be had ix-ady for use in a variety of colours, and admits of the application of varnish or enamcl as a final coat without; lessening in any way its iireresisting qualities. The favourabie impression made by experinients is confirmed by the offer of at least one English insurance company to make a suhstantial reduction in its fire insurance premium-s where wooden buildings are protected by this paint. A PHOTOGRAPHIC INVENTION. A new invention, greatly accelcrating speed at which cinematograph fiims may be taken, has- been demonstrated. By means of special electrical Tapparatus producing 50,000 sparks per second, it is possible to .obtain 50,000 different posittons of a projectile jn the course of its passage Through the air. Experts stated hitherto, 2000 photcgraphs per second had been the record. Tb.e new discovery means a revolution in e-xperimental science and in medicine,, especially in raaiography. It will be possible to sltidy circulation of blood, the play of muscles, and everything movin.g in the body with much greater exactitude. THE WIRELESS UMBREELA. Aho the r stepping-stone along the steady march of wireless prcgress was disclosed at a meeting of the Wireless Society of London, when Captain DonistBbrpe ex-hibitc-d a new pocfeet-book wireless receiver. By using this new ' receiver, it will soon be practicable to walk about in the street, and pick up wireless message- as we go along. To all .appearances. thi > poeket-book resembles. an ordinary note-book, except that it is rather larger ant heavier. If we clip a wire from a small aerial on to one metal corner, and ancther from a convenient waterpipe on to the other, and push the plug of a pair of telephones into the hinge of the boek, we have a wireless receiver complete, which will give us a message from | frien-ds across the ocean. The wmdings of the receiver are concealed in the eovers of the hook. To use our umbrella as the aerial and our boots as the earth connection is but one more step forward, so if we carry one of these books with us we need not fear if our watch stops ; w« shall put up our umbrella, open the book, and pick up the time from the Eiffel Tower. THE NOISELESS TYPEWRITER. Few sounds are mere nerve-racking than the clatter of typewriters, and it is not surprising, therefore, that many efforts have been made to eliminate this drawback. As a result, a machine- has been evolved known as the "Noiseless Typewriter." This appliance is almost silent, only a faint clicking noise being audible. What makes the ordinary typewriter so noisy is the constant succession of hammer-blows given by the type upon th,e platen roller. When a key is pressed down the type and the sliding frame carrying it shoot out with constantly increasing speed until pulled- up with a snap on the paper. In the noiseless typewriter tbis rate of motion is reversed, the sliding frame travelling fast to begin with, and more and more slowly during the remainder of the stroke, until it has almost stopped by the time the surface oi the paper is reached. Just at this point, a tiny weight, which, brought into action automatically, has been gather-in-g momentum during the stroke, comes into play, and presses the type forward. The effect of its working is to produce a strong pressure and to ensure perfect registration on either one or more copies.