Science Siftings

New Zealand Tablet, 15 June 1916, Page 45

Science Siftings

By ‘Volt.’

In Place of Cotton-Wool. It is only recently has been drawn in the United Kingdom to the, remarkably absorbent and cleansing qualities of sphagnum moss when used as a dressing for wounds in place of the familiar cottonwool. The great strain that has been put on the surgical dressings generally employ, has compelled surgeons to look about for a substitute, with the result that sphagnum moss is being more and more called upon for the purpose. The new n. oiks are to be opened in the Scottish capital, where the mo.-s will be treated and made ready for use. The moss is uot being prepared as a commercial undertaking, but merely to afford assistance in a good cause. How the Victoria Cross is Made. Hitherto the most coveted British war decoration, the Y.C., the intrinsic value of which is but a few coppers, has been made from bronze from Russian guns. Russian metal, however, being now withheld, the medal is being made from Chinese gun metal. The first process of manufacture consists of obtaining a rough cast die by melting the metal at a temperature of 200 deg. Pah. and pouring it into a mould. The cast is then trimmed and chased, at which stage it has to be inspected by the War Office and passed. Then the Cross is sent back to the makers, who wait for the name of the recipient, the bar and the ribbon being added—blue for the Navy and red for the Army. Why They Walk in Circles. ‘ If you were lost in a desert or in a forest and tried to find your way out,’ says a well-known scientist, ‘ you would be almost sure to walk in a circle. ’ This well-known fact is due to a slight inequality in the length of the legs. Careful measurements of a series of skeletons- have shown that only 10 per cent, had the lower limbs equal in length, 35 per cent, had the right limb longer than the left, while in 55 per cent, the left limb was the longer. The result of one limb being longer than the other will naturally be that a person will unconsciously take a longer step with the longer limb, and consequently will trend to the right or left, according as the left or right leg is the longer. The left leg being more frequently the longer, the inclination should take place more frequently to the right than to the left, and this conclusion is quite borne out by observations made on a number of persons when walking blindfolded. The inequality in the length of limb, is not confined to any sex or race, but seems to be universal in all respects. 4* Torpedo Secrets, At the torpedo’s head is an explosive chamber, which holds damp^gun-cotton. This is fired by means of a rod which, on contact with the walls of a ship, is driven in upon a detonator. This fires a primer, which in turn explodes the gun-cotton. The next chamber stores compressed air to the pressure of 20001 b to the square inch. This is practically the boiler-room of the torpedo, for it supplies the motive power to the fourcylinder engine which drives it through the water on its errand of destruction. Next comes the wonderfftl gyroscopic control of the air-motor by which the rudders are adjusted. This is where the intricate mechanism of the torpedo is so clearly demonstrated. Should it rise or dip in the water, this gyroscope actuates a mptor which in turn operates rods related with the rudders, and at once readjusts any deflections from the course originally set. The motor mentioned is but a few inches in length, yet the power it exerts by means of compressed air is such that the pressure of Joz operated by the steering-gear produces a pull of 1601 b on the rudders. This terrible fish’s tail holds wheel gearing for the driving of two propellers and the manipulation of the rudders. The propellers revolve in opposite directions, thereby preventing the torpedo describing a circle. :