SCIENCE NOTES.

Digger (Invercargill RSA), Issue 33, 29 October 1920, Page 13

SCIENCE NOTES.

NON-LEAKING STORAGE BATTERY. A. new storage '-battery said to be absolutely non-leaking has been produced. It has a special valve to Let off the explosive -gas, so arranged that no abid can get out. The plates are separated by strips of wood which not only prevent short-eir-cuiting inside the cell, but retain the acid when t.he storage battery is upside down, giving an electricai efficiency of 75 per cent- in this position. This battery is a German invention. A SAWDUST STOVE. The coal shortage which many of the Earopeair countries face has not failed to spur in ventors in the direction of new fuels and stoves. Cne of the most recent attempt-s to solye the heating question consists of a special stov© whieh bur.ns sawdust. The stove consists of a i cylindrical casing provided with suitabLe holes for draught purposes, and suitable holes for draught purposes, and a e.ontainer which is packed with sawdust. Once ignited, the tightl.v-packed sawdust is said to burn slowly and evenly, giving considerable Aieat. A single charge of sawdust burns twelve hours. The action it is said, is very much the same as coal as far as smooth burning and the intensity of heat are concerned. RAILROAD ELECTRIFICAT 10N. Coal as a power producer will be replaced so far as possible by the use of peat and the. electrifieation of railroads in the vicinity of the large German cities, Great hopes are Eeing placed on the new Theissen 10,000-horse-power vertical gas turbine, two of which have been ordered i'or use on the German raihvays. It is hoped that they will be able to replace the coal-burning locomotives. In regard to the electrifieation of the German railways near large cities it is plan ned to instaii large central power slations, which will be equipped with peat-burning f-urnaces. The* peat bogs in the vicinity of Osnabruck wili furnish this fuel. 3Ma. chinery for the working of this peat has been installed, and experiments are being made bv the German Government witn machin, ery lor pressing the peat, so that it may ha transported economically. COALS FOR BY-RRODUCT COKING. While the chemist can make an accurate analysis oi coal, it is not generally under. stood that such analysis cannot give results in terms of by-products from gas or coking operations. The chemist determines the elements which, under suitable conditions, combine to form ammonia, benzine, toluene, tar, etc., but he does not separate the coal into these suhstanGes. The amount of these by-products which will be produced depends upon- many ccnditions, and indeed more upon lle operation of the plant than wpon the character of the coal. It is necessary to coke -.001 under commercial conditions and even a small-scale plant can do no more than indicate the possibilities so far as our pr« sent knowledge is concerned. In all this work the laboratory and semi-commeroial-scale plant is a very valuable guide, but the limitations must be recognised. TESTING THE ATMOSPHERE. An . instrnment for revealing the quan tity of solid matter and the gaseous impurities in the atmosphere has baen de-

vised. For instanee, if there is an excess of smoke, or other extraneous material hovering over yovu* city this apparat.is would doubtles'g answer the question, ' Is this super-abundance of smoke, say from a foundry, bu'rdened with impurities which are detrimental to the inhabitants of vbe city?" The device is in practical use in Salt Lake City, Utah_ The instrument is able to detect and measure sulphur c'ioxide, and is capable of revealing the presence of one-tenth p.art in one miltton. The weather barometer, a part of the equipment, contains a filtering thimole material. The air is measured by meter, which ekes out the goot and other * "id matter, and then passes through small bottles, Containers of which absorb the nitrous oxide, ammonia, chlorine, and other gaseous impurities. Another ovli-e determines the amount of carbon dioxide. A motor-driven vacuum pump forces the air through the apparatus. The job is complete— the percentage of >gaseou8 impurities in the atmosphere is revealed.