SCIENCE NOTES.

Digger (Invercargill RSA), Issue 27, 17 September 1920, Page 15

SCIENCE NOTES.

A NEW STORAGE BATTERY. A new type of storage battery is described in a rencent issue of "Science Abstracts." This new battery appears to be a modification of the nickel-iron alkaline cell as made by j ungne.r, the chief characteristic being the method of making up the plates from briquettes of active material ,which are autoxnaticaKy fed in between two perforatcd nickel-steel strips. These strips enciosing the active material are manufactured in lengths folded together and fitte,] into a steel frame. The cornplete electrode is theii put- through a rolling process to ensure perfect contaet between. the active material and the strips. Only a brief indicatibn is given of the methods followed. A BY-PRODUCT FOR ENAMELS. Some phosphate rocks carry an amount of fluorine sufficient to lead one chemical engineer to consider methods for its recovery and utilisation, Following a series of experiirrents the teohnique oi recbvering this fluorine from the acid phosphate plants was devised and sodiuin silicofluoride produced. The grade is very sat. isfactory and the product has the ad'vantage of being reasorfably constant in quality. This material bids fair to be sub. stituted for cryolite, an essential ingredient in the type of enamels used on cast and sheet metahvarc. Most of the cryolite is imported from Greenland, so that the reeovered by-product has a considerable advantage in cost of transportatiori and handling: SHERARDISING. Sherardising is not. merely the applicatiOn of a zinc coating on iron or steel, as is the case with electro-plating and galvanising. The . coating. produced by sherardising is an alloy with tfie underlying rnetal tipon which the outer layer of zinc is aftcrwards dcposited. The zinc therefore. enters into every crevice and cavity, making the process quite defferent from any other method of nc coating. Tho coatirg is not as hard as- it is in the cass of galvanising, for which reason it is considered 'more desirable for special uses, as. v.n.ere piec-es must withstand severe strainmg and behding and still retain their rust-resisting qualities. It- is impossible to give sherardised metal a hnish comparable to nickel plating or silver plating by boffing on a fine polislnng wheel ^and finishing on a cloth wheel. FOOD SOURCi-.S Statistics were given before the American Philosophical Society with refdrence to the various sources of the chemical eompounds which make np the .cssentiais in our diet. Mere than £0 per cent. of the protein is contained in animal foods other than fisb; 35 per cent.. including 28 per cent. from wheat, corrie, from grains ; 26 per cent. from meat-s", 20 per cent. irom dairy products, and about 7 per cent. from poultry and eggs, Of the fat eajten, 51 per cent. is derived from meats, including 40 per cent, derived from pork and its products, 27 per cent. from dairy products. 12 per cent. from oils and nuts. Our earbohydrates are principally from grains which supply 56 per cent., 26 per^cent. is from sugar, and the reniainder is to be found in frurts and vegetables and dairy products.

' SOUND AND NAVIGATION. There has probably been more leamecl about sound and' its transmisslon during the pastr foor ^ears than during all the rest of time. Listening dcvTces installed outside the shrp's skin, or within ship's taiiks, not only distinguish different sound sources at considerable ranges when the sliip is under way, but the direction can be obtained within an accuracy of two or three degrees. . For example, the multiple-unit microphones with elect:. ? compen,sator placed on the Von Steuben enabled that vesse!, when runnii^i at full sp.eed, to heav the . aibmarine lell on Nantuckefc lightship, at a distance greater thia 35 mries, It rnay be safely stated that a distinctive sound souree, as a submarine cscillator, can be hearcl at all iimes, and during ail kinds of weather in deep water, at a distanc.e of 20 mil.es or more. In addition to obtaining bearings ,of - distant sound sources. theso devic-es may be utilised to -determme fairly accuratcl-y the depth of water.