ο»Ώ SCIENCE NOTES AND NEWS.1 .-|1919-06-05|The Brecon County Times Neath Gazette and General Advertiser for the Counties of Brecon Carmarthen Radnor Monmouth Glamorgan Cardigan Montgomery Hereford - Welsh Newspapers Online
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SCIENCE NOTES AND NEWS.1 .-

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SCIENCE NOTES AND NEWS. 1 POISON GASES IN SUNKEN VESSELS. In addition to the introduction of poison-gas as a weapon into modern war- fare, Germany is indirectly responsible, writes Herbert Stringer in the Star, for the discovery of several gases hitherto un- known to science-gases far more subtle and deadly in their effects than even the most recent compounds of the" stink" specialists. This discovery was quite accidental. The holds of sunken vessels are the "laboratories" in which these "super- gases are spontaneously generated. The entry of sea water into the damaged com- partments of ships laden with grain, ootton, linseed, soya bean. or similar car- goes, ets. up intricate chemical reactions in combination with the metallic surfaces I sur es exposed, and the result is the production I in due time of certain elusive gaseous com- pounds which have not yet been classified by chemists. I Naval men engaged upon salvage work I at sea have many strange yarns to tell ot the swift death that lurks in odd corners of the holds of newly-raised vessels. The mysterious gases are usually odourless and invisible, and they will penetrate the very best gas mask. Some are lighter than air, some heavier, and they hang about at very sharply-defined levels. Sometimes a layer of deadly gas will be found floating a few feet from the floor of a hold, while the upper and lower airs remain perfectly harmless. The usual expedients—lighted candles, white mice, &c.—which are commonly em- ployed for testing suspected wells and caves or disused mines, are of little avail in detecting the presence of these new gases. The more insidious vapours steal out of the cargo while work is suspended during the night, and in the morning the holds may be veritable death-traps. At times, too, the shifting of parts of the cargo may release a rush of imprisoned gases, which will often remain undetected until a life has been lost. The most wonderful feature connected with these gases is that, although nobody yet knows exactly what they are, chemists have discovered an antidote which, when sprayed into an affected area, absolutely neutralises and renders harmless even the most deadly of them. The composition of this liquid is at present a profound secret. It has already given most surprising re- sults when applied to bad drains, and also in the treatment of septic wounds and gangrene. ELECTRIC METERS FOR STREET CARS. The Electric Railway Journal gives some instances of the utility of meters on street cars with a view to checking waste of energy. Some comparative tests, made with the same equipment on level linea and gradients, show that as much as 26 per cent. saving in energy could be made in this way. Originally 2'093 kilowatt- hours per car-mile was obtained in a test in which the dials of all meters were kept covered, so that the driver could not ob- tain any information as to the current he was taking. Subsequently, after a period of training in which instruction was given on the handling of cars, by observations of meter readings an energy saving of 0 253 kilowatt-hour per car-mile (about 12 per cent.) was obtained-in spite of the fact that climatic conditions were less favourable than in the first trials. On very severe hilly routes it was eventually found that the energy consumption coula be re- duced from 3 41 kilowatt hours to 2'52 kilowatt hours per car-mile—a saving of 26-1 per cent.—mainly due to better hand- ling of controllers arid brake equipment. I SOMETHING ABOUT SELENIUM. A very dull sort of element is selenium; but it has a part imany of the most won- derful discoveries of the day, writes Atom in Everyman. By means of it Admiral Beatty was able to talk from his ship with the Admiralty in Whitehall. By means of it the police in Edinburgh, say, could send by telegraph the photograph of a criminal to Scotland Yard or New York. And totally blind people have been enabled to distinguish light through the use of selenium. The element was discovered just over a century ago, and was called selenium (from the Greek word meaning moon), because it resembled tellurium (which means earth). It is found in a few minerals, sometimes with sulphur and sometimes in the native state. Usually it is obtained from the flues of sulphuric acid works in which pyrites containing selenium has been burned or it can be extracted from the mineral zorgite. Sometimes it exists as a viscous liquid, sometimes it is in the red crystalline form, and there is, thirdly, the crystalline grey form. Selenium dissolves in concentrated sul- phuric acid, and it is slightly soluble in carbon bisulphide (anyone who has worked with rubber knows this evil-smell- ing liquid !) from whch the red variety can be crystallised out. It combines with numerous elements and with all the metals, except gold; but neither itself nor its com- pounds play much part in the world except for one peculiar property. It is non- roetallic, but it conducts electricity, and its conductivity and resistance vaTy under the influence of light. It is this latter property which haa given selenium a foremost place in several of the most wonderful inventions of our time. Of course, it is not wonderful that the electrical conductivity of a substance should vary under the influence of light, which is itself an electro-magnetic pheno- menon; and the property has since been found in other substances. But selenium was the first to exhibit such reactions. A certain caprice seemed to be evident in the reaction to the stimulus of light when the matter was first investigated. A- selenium cell is most sensitive, under a very bright light, to the red rays; whereas, in a weaker light, the most sensitive joint is in the green rays. It is this that ex- plains the evidence of some observers that selenium was most sensitive to red light, while others reported that it was most sen- eitive to yellow. It is the brightness of the light which moves the point of maximum sensitiveness along the spectrum. This variation is not so strange as it seems, since the action of the eye is very similar. In very weak light, red seems to produce hardly any effect upon the eye, whereas the greens pnd blues show *p strongly. THE CRYSTAL STRUCTURE OF ICE. The X-ray study of the crystal structure of ice by a prominent scientist was ren- dered difficult by the fact that the rays tend to melt and to sublimate the ioe. In & first attempt to turn the difficulty the whle system was encased aafl oeoled bv ice ana sait; later a small ammonia machine was used which stopped the melt- ing but not the sublimation of the ice; finally the crystals were encased in gela- tine capsules in waich they could be pre- ) served for days. From a layer of ice two millimeters in thickness, produced by pouring water into a pan, individual crystals could hardly be extracted; finally ice was frozen out of a weak salt solution which yielded crystals with distinct cleav- age planec,. Tne crystals were found to be hexagonal, and could be referred to four inter-penetrating triangular space lattices, and to two axes meeting at an angle of 120deg., and a third axis vertical to the) i former. I

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