July io, 1919] 



NATURE 



m 



In a paper publisht'd in the June issue of the 

 Journal of the Franklin Institute Gen. Squier describes 

 experiments made on the use of trees as antennae in 

 1 adio-telegraphy and radio-telt phony. He discovered 

 in 1904 that certain trees, especially eucalyptus trees, 

 could be usefully employed as antenna;. Owing to 

 the dryness of the season and the nature of the soil 

 at his camp in California, the regular .\rmy "buzzer" 

 telegraph and telephone sets were inoperative. When, 

 iiowever, they were connected to a nail driven into 

 the trunk or roots of a tree they worked satisfactorilv. 

 During the war experiments were made on the 

 efficiency of growing trees as antennae. With modern 

 sensitive amplifiers it was discovered that it was 

 ])ossible to receive signals from the principal European 

 stations by simply laying a small wire netting on 

 the ground beneath a tree and connecting it by an in- 

 sulated wire to a nail driven in near the top of the 

 tree. Instead of the wire netting, a few insulated 

 wires buried a few inches in the ground were found 

 to answer perfectly. Interesting tables are given 

 showing the resistance and capacitv of the conductor 

 for various heights of the nail, and also by indirect 

 methods^the open-circuit voltage inductxl in the con- 

 ductor. 



The Proceedings of the Physical .Society for June 15 

 contains as an appendi.K, which has been issued 

 separately, a report of the discussion on metrology 

 in the industries which took place at the meeting of 

 the society at the end of March. The discussion was 

 opened by .Sir Richard Glazebrook, and many manu- 

 facturers and others who had been concerned in the 

 use of gauges in testing the accuracy of munition 

 u ork turned out during the war took part in it. One 

 of the most important facts brought out in the dis- 

 cussion was that many works which, by the use 

 of gauges, were enabled to turn out work of a 

 much higher order of accuracy than they had ever 

 'nought possible were now reverting to the old rule- 

 l-thumb methods. .Since quantity production and 

 ntcrchangeabilitv Jire likely to prove essential features 

 if the work of the future, it was suggested that this 

 I'version should be so far as possible prevented by 

 he issue of gauges in which the difference of size 

 f the "go" and "not go" was considerably greater 

 iian in thos(^ used in first-class work. By this means 

 the valuable principle of working to gauge could be 

 retained -even for the rougher work, and any future 

 increase of accuracv which might be necessary would 

 involve nothing more than a change of the gauges 

 in use. 



The interesting new method of X-ray analysis 

 initiated by Debve and .Scherrer has been employed by 

 .A. J. Byl and N. H. Kolkmeyer to investigate the 

 structure of ordinary white tin and the second variety 

 of this metal known as grey tin, and an account of 

 'heir work is published in the Proceedings of the 

 \cademy of Sciences of .\msterdam (vol. xxi., 1918). 

 1 he method is eminently suitable for metals not avail- 

 able as single crystals, and for micro-crystalline sub- 

 stances in general. An X-ray tube with copper anti- 

 cathode was used, the rays leaving the tube by an 

 aluminium window. They nassed thence through a 

 narrow aperture in a thick leaden screen into a 

 cylindrical camera. The tin lay in the axis of the 

 cylinder in the form of a narrow bar, in one case of 

 white hammered tin. and in the other of compressed 

 j^rey tin. .\ photographic film, on which the inter- 

 ference lines were found after development to have 

 been produced, was stretched against the wall of the 

 camera. The interference lines resulting with grey 

 tin showed at once that this variety of tin is also 

 crystalline, and that the crystals belong to the cubic 

 N'.). 2593, VOL. 103] 



system. There appear to be eight atoms of tin to an 

 elementary cube, which corresponds with the same 

 structure as that of the diamond, and also with that of 

 silicon. The tin in this form is obviously tetravalent. 

 Ordinary white tin. according to Miller's measure- 

 ments with electrolytic crystals, is tetragonal, and this 

 fact is confirmed by the' interference lines found in 

 the experiments with the bar of this variety of tin. 

 There appear to be three atoms to the elementary cell 

 of the space-lattice, an atom lying at each corner of 

 the tetragonal cell and one in the centre of each of 

 the four prism faces of the cell, but none in the 

 centres of the two basal-plane faces. This structure 

 corresponds with atoms exhibiting prominently two 

 valencies only. It would thus appear that grev tin 

 possesses a structure corresponding with the exercise of 

 the full tetradic valency of tin in the stannic salts, 

 and ordinary white tin a structure corresponding with 

 the exercise of its dvadic valencv in the stannous 

 salts. 



The first number of a new chemical journal, the 

 Chemical Age, was issued on Saturday, June 21. The 

 journal is to appear weekly, and to be devoted to 

 industrial and engineering " chemistry. It is now 

 nearly five years since the Chemical World, a 

 journal with corresponding intentions in regard to 

 chemistry and chemical engineering, ceast^d to exist 

 after the production of three volumes. Many people 

 regretted its demise, for it was full of interesting 

 matter and well got up, but the cause of its early 

 failure was probably the fact that there was only a 

 monthly issue, and something was wanted to keep 

 pace with the current of events, rapid even before the 

 war. This is more than ever true at the present 

 time, when it may be said that the British manu- 

 facturer and the British public are at last waking uj) 

 j to the necessity of associating science with industry. 

 j The new journal has a larger page than the Chemical 

 World or any of the other technical chemical journals, 

 I and is brought out at the moderate price of 2i.v. per 

 I annum, or 6d. a week. The first issue contains a 

 I number of interesting expressions of opinion from 

 I public men, including Mr. H. .\. L. Fisher, Lord 

 I .Sydenham, and well-known experts, including Sir 

 j Edward Thorpe, ("ol. Brotherton, Mr. James Swin- 

 burne, and others, in regard to the future of British 

 I chemical industry. On this subject there can be little 

 I difference of opinion, if only the same energy and 

 j skill already displayed continue to be ernployed 

 I and foreign competitors are excluded, at least for a 

 time. The issues of the Chemical Age which have 

 j appeared so far contain matter of importance to every 

 I practical man connected with chemical industry, and 

 ] we wish the new venture full success. 

 I 



j .Some analy.ses and tests of rigidly connected re- 



I in forced concrete frames are given in the I'niversity 



j of Illinois Bulletin (vol. xvi.. No. 8). The author, 



I Mr. Mikishi .\be, derives formulae for a number of 



j such frames by the method of least work. Test 



I frames were then designed according to the formulae, 



I and the experimental results were compared with 



those obtained by calculation. It was found that the 



elastic action of the frame and the manner of stress 



I distribution agre<^ fairly well with the analyses; that 



' the locations of the points of inflection agree closely 



with the calculated positions; and that in carefully 



designed frames there need be no anxiety as to the 



rigidity of the joints, since effective continuity of 



members was found in the tests. 'I'here is a number 



of other deductions from the results which will be 



. of service in design, and it would appear that the 



I formula? derived bv analysis mav be applied to a 



j variety of forpis of frames and ar( ^f wide applic- 



