SCIENCE NOTES.

Otago Witness, Issue 2003, 14 July 1892, Page 44

SCIENCE NOTES.

— The system of great gun construction, known as the Brown 6egmental tube wirewound metbod, which it is claimed, is destined to revolutionise the fabrication of heavy ordnance, has undergone :i completely successful trial, uuder Government auspice.-, at. the works of the Pennslyvania Diamond Drill Manufacturing Company at Budsboro, Pa. Tbe Brown qua is to be constmotcd of a iube of 'accurately adjusted segments of fctecl, extending from breech to ruuzz'e, vrapp'-d with many layers c-f steel wiie, applied under heavy pressure, and lin^d witii an inner tube to carry tbe rifling and endure •wear and tear of repeated firing. A complete gun lias not yet been finished, bat a gainpls cylinder, representing tho ponder chamber of a sin gun was subjected to the trial yesterday. The external diameter was a trifle under*l6in and its length about 2fc. Tbiee and a quarter pounds of powder

gave the enormous pressure of 52,8501b to the square inch. The highest pressure used in modern guos does net exceed 35,0001b. — Manufacturers' Gazette. — A French scientist has invented a new kind of porcelain, the primary constituent in which is asbestos, ground to an impalpable powder, and made into a paste with water. This paste is moulded into any form desired, and then dried in a stove. Id is then baked in what is technically termed a " Beggar " (a case of fire-clay) for 16 or 17 hours, the temperature at the end of which period is about 12000deg. A porcelain is thus obtained more translucent, it is affirmed, than ordinary porcelain. It can be used for the perfect filtration of liquids— acids for example — and it is also claimed that it prevec ts the passage of micro organisms. Thus a liquid containing 12000 microbes per cubic centimetre was absolutely sterilised by filtering it through this medium.

— The Plattnotype Company of London have recently brought out a lamp, the invention of Mr E. J. Humphrey, which promises to be of great value to photographers, and may posEibly find employment for signalling and other purposes where brilliant illumiuation for short peiiods is required. The lamp consists of a hollow metallic vessel, which is charged wiih a spoonful of magnesium dust. Ordinary household gas is carried into the lamp by an attached rubber Lube, while ano:her tube feed.* it with oxygen The tubes within the apparatus art so arranged that tho hydiogea burns within two walls of oxygf n, and tbe force of the former pas is Fuflicient to c:irry into the compound ilamo the metallic dust. The result is a light which is dazz'ing in its intensity, and which is so chemically active that it can not only he used for photographic portraiture but can be used advantageously for printing pur-

poses. By a slight modification, a large quantity of the magnesium dusfc can be forced suddenly into the flame, so as to afford a 'flash' lighb suitable for instantaneous work at night. The lamp is portable, and can be ased wherever gas is at hand.

— In the grcunds of the World's Fair at Chicago there has been running for some time experimentally a tram car which is fireless, steamless, and noiseless, which its promoters hope will supersede the use of horse?, cables, and electricity for street tramway purposes. It is fitted with a motor which owes its power to the expansion of ammonia from the liquid to the gaseous state. The pressure obtainable is nearly 1501b on the square inch, and the ammonia, after having done its work, can be again condensed to its original state at the generating work?, and can be used over again. With one charge of ammonia the car will run 18 miles ; and the operation of removing the spent gas, which is absorbed in a water tank, and recharging occqpies only two minutes. The working expenses are wonderfully low, and it is believed that the system has a wide future before it.

— A German aeronaut, Herr Heiorich Lattermann, says Iron, has devised two aerial machines which are attracting much notice on the Continent. The first is a new kind of parachute, which, it is stated, is but half the size of any hitherto used, and can be rolled up like a cloak. When the hazardous leap is made, the parachute instantly unfolds and expands. This form of parachute is considered to be of great importance in view of its lightness, permitting several of the apparatus to be carried and used in case of emergency by as many persons It is added that the parachute can he employed in any weather without danger of entanglement in the network of the balloon. A further advantage is claimed in that the rapidity with which the parachute opens renders it possible to the aeronaut to descend almost on the spot whence he embarked, as precipitation from the balloon may take place from a comparatively insignificant height, before the balloon has begun to make much lateral headway. The second invent ion is a gigantic parachute balloon, the characteristic feature of which is the capabi'ity of a balloon of a capacity of about 1200 cubic meters being converted into a parachute. The balloon is of spherical shape, and is so constructed that the under portion may, at any decided moment, be caused to collapse within itself. Tbe balloon then assumes, it is said, the form of a huge parachute of more than 40 meters circumference. The integument of the balloon is, as a precaution, prepared with asbestos and other fireproof materials. Heated air for filling the bag is to be supplied by a furnace of Hatteman's own make. The first ascent with these new apparatus will shortly be made in Berlin. In August the inventor purposes proceeding to Chicago, with the object of making arrangements for a series of aerostatic exhibitions during the forthcoming exhibition in that city.

— Tbe substitution of glass by a new chemically prepared substance, the details of which have lately been published, appears to have taken a definite form, and is expected to take its place among the practical industries. It is produced by dissolving from four to eight parts of collodion wool in about 100 parts, by weight, of ether, or alcohol, or acetic ether, and with this are intimately combined from 2 to 4 per cent, of castor oil, or other oil that is non-resinous, and 4 to 10 per cent, of Canada balsam or some other soft resin balsam. This compound, when poured upon a glass plate and subjected to the drying action of a current of air of about 50deg Cent., solidifies in a comparatively short time into a transparent , glass-like sheet or plate, the thickness of which may be regulated as required The sheet or plate obtained in this manner is found to possess substantially the same properties as glass, it being capable of resisting the action of salts aid alkali, and of diluted acids, beiug also transparent like glass, and is without any odour. On the other band, the peculiar advantage is claimed for this new article of being pliable or flexible, and infrangible to a very considerable degree, and an additional quality in its favour is that its inflammibility is much less than the ordinary collodion substitutes.