Science Siftings

New Zealand Tablet, 3 June 1915, Page 49

Science Siftings

By 'Volt.'

The Biggest Gun. The biggest gun in the world—unless the German army has larger ones not known to other nations—shipped from the Watervliet arsenal, New York, recently, where it had been sent to be rebored, to the arsenal at Watertown, Massachusetts, to be remounted for coast defence service" at the Pacific Ocean end of the Panama Canal. The gun is the big 16in. rifle built at Watervliet in 1896 and" placed in service at Sandy Hook. It was 49ft 4in in length, and weighs 284,500 lb. The diameter at" its breech is sft, and at the muzzle 2ft siin. It fires a projectile weighing 14001 b a distance of twenty miles, and it costs Uncle Sam in the neighborhood of .£2OO every time the big piece of ordnance is fired. It requires 6001 bof gunpowder every time" it is discharged. The Sun and Earth. The abnormally inclement spring weather experienced in Europe gives practical importance to the statement by the Vail Mall Gazette that during the last days of March great things were happening on the side of the sun hidden from our view, the occurrence of which was made known by the appearance at the sun's eastern limb of one of the most imposing.,collection of sunspots seen for many years. The leaders of this group reached the centre of the sun during the Easter week, and from this vantage ground (so argue those who trace to them our weather troubles) sunspots are potential to bring their biggest meteorological guns, so to speak, to bear on our unfortunate planet. A theory of sunspots, enunciated last year by Professor 11. TI. Turner, ascribes them to the Leonid meteors and the rings of Saturn. A thorough grasp of this theory needs an expert mathematical mind : but, simply put, the idea is that now and again the meteors, rushing through space, bump into Saturn's rings, and fragments from the satellites, of which the rings are composed, are, as a result, hurled with tremendous violence into the glowing atmosphere of the sun. The cavities-thus produced in the photosphere are the sunspots we see. The Vision of Submarines. The Standard says that the ' sight' of the submarine has been greatly improved, and the modern periscope is fitted with a compass by means of which it is possible for a helmsman to steer to fractions of a degree instead of, as hitherto, to quarter-points only. By this the accuracy with which a torpedo can be fired is greatly enhanced, and in the newest boats it is possible to obtain the bearings of an enemy ship from a distance of some miles away and set a course which, without it being necessary to use the periscope again, will bring the boat to a point from which a torpedo may be fired with an absolute certainty of its mark. The earlier forms of periscopes were frail and leaky, and a-constant source of trouble. The new types are not only robust, but the glasses have no tendency to become cloudy, and, no matter in what position the object viewed may be, the image thrown is always erect, and not at times inverted, as in the older instruments. The bearing of the object viewed is indicated by a movable pointer on a fixed dial. The new pattern of periscope is also arranged that if desired a magnifier can be brought into -operation whereby a vessel invisible to the naked eye can be seen and its exact position calculated with mathematical precision. Once this has been worked out, the submarine, as has already been mentioned, can be submerged and her periscope drawn in and an underwater course pursued until the exact position at which the torpedo should be fired is arrived at. It may be added that in all modern vessels. the firing can be done ' from the periscope ' — i.e., the officer who is watching the periscope and telltale when they are in use can himself fire the torpedoes without leaving his post, -