Science Siftings

New Zealand Tablet, 10 June 1915, Page 49

Science Siftings

By Volt.'

'-■■--•: Metallurgy and Gunnery. -. The Standard remarks that one of the strangest mistakes that has been made by Englishmen in modern times has been the idea that big guns were made out of iron. A lesser mistake was that steel was only a compound of iron with a certain quantity of carbon in it. At the present time there are never less than five and often more than ten elemental metals in an ingot of what is still called steel. We know nothing of the composition of the alloy that has been built into the splendid 15in guns of the Queen Elizabeth that are engaged in the bombardment of the forts of the Dardanelles. The exact compositions of the metal the gun is made of might be easily ascertained by a careful analysis, but it would be no good at all to the engineer who wanted to make the gun. Every separate part of even the smallest gun is made differently, and many alloys are worked into its mechanism. Lighthouses for Aviators. In Germany there are specially-built land lighthouses, whose purpose is to guide aircraft. Each is fitted with a powerful searchlight which, at intervals of a minute, throws out a flash of 27,000,000 candle-power.-These beacons send a powerful ray of light vertically up info the clouds, so that it can be seen by aviators at great altitudes. Such guides are mounted on prominent spots. Each lighthouse has a certain distinctive flash, so that its geographical position can be ascertained by aviators passing overhead. The German land- lighthouses are also fitted with wireless apparatus, which at frequent intervals sends out weather reports which are caught on the aerials of passing aircraft. * In this way aviators for many miles around can be warned against approaching wind or rain storms, for almost every German military aeroplane carries wireless equipment,, which enables its pilot to keep in communication with the earth beneath. Early Submarines. I heard someone say the other day that the French invented the submarine, but this is not true (says a writer in the Universe), It is quite true that over a century ago the French Government spent a lot of money in perfecting the invention of an American, and that a series of submarine tests were made at Brest and Rouen, and that at Brest a submarine boat succeeded in remaining about four hours under' water, during which period the vessel fired a torpedo which sank an old hulk lying in the harbor. But the torpedo had to be attached to the bottom of the boat which was blown up. The first inventor of the submarine was a Dutchman named Drebel, and this boat was tried in the Thames by James the First. This hoary ancestor of the modern engine of destruction is mentioned in Boyle's New Experiments (Oxford, 1660 J, and a full description is given of it. Obviously, it aroused the greatest attention, and after Drebel had astonished the world with his under-the-sea boat an English bishop, named Wilkins, who was noted more for his mechanical, rather than theological, aspirations, gave the submarine idea a strong impulse by writing a full chapter on its possibilities in his book, Mathematical Majick. He called it an Ark for submarine navigation.' The story of the submarine was carried on from chapter to chapter till the year 1886, when the 'grandfather' of the present submarine was born in Stockholm. Driven by steam, it was the invention of one Nordenfelt, and ran 16 miles at a speed of 5 knots. Although it came up to expectations, yet, somehow, the critical eye of the experts looked upon it as useless, nor were .they appeased even when the Turkish Government ordered two boats. The original boat lay at Copenhagen, and she was finally broken up. Then France took the matter up seriously in 1897, when she bought the plans of the Peral and constructed four-boats of this type, or something very similar. She did two trials of about 120 miles underwater at a speed of about seven knots, and discharged a torpedo at 400 metres. - \: t . %. ■-■■' •■-,■- :.;■":.' .:.,;