348 



NATURE 



[June 22, 1916 



In an address to the American Institute of Electrical 

 Engineers, which is reproduced in the April number of 

 the Journal of the Franklin Institute, Mr. J. D. Ball, 

 of the General Electric Company, Schenectady, gave 

 a resume of the results obtained by him in his recent 

 examination of the magnetic properties of steels and 

 other materials. He finds that for pure materials the 

 reluctivity when plotted against magnetising force H 

 gives a straight line from H = io to 400, and that the 

 hysteresis loss per cycle for such materials varies as 

 the ibth power of the maximum induction. The 

 deviations from these laws which have been found 

 by other observers are due, he finds, to the use of 

 impure or mixed materials. A mixture of two mate- 

 rials which follow both laws follows neither at high 

 fields. In the case of steels the presence of scale on 

 the surface is sufficient to account for the observed 

 deviations from the two laws. The paper contains a 

 number of tables and curves showing the magnetic 

 properties of steel, cast-iron, and scale. 



Smokers have hitherto been iniplored — or compelled 

 through heavier taxation — to practise war economy by 

 avoiding, or at least restricting their use of, tobacco. 

 Now it seems that were one of the products of their 

 indulgence to be collected they would become national 

 benefactors in disguise. In an article in the Chemical 

 News for June 2 Mr. B. A. Burrell points out that 

 tobacco ash contains 20 per cent, of potash. A cigar, 

 cigarette, and pipe of tobacco of ordinary sizes, weigh- 

 ing severally 106-5, 27, and 255 grains, will give ash 

 containing respectively 6-5, 175, and i-6o grains of 

 potash. (We think that there must be some mistake 

 in Mr. Burrell's figures, since in our experience ordinary 

 cigarettes weigh eighteen to twenty to the ounce, whilst 

 it is difficult to obtain more than fourteen "pipes" 

 from an ounce of tobacco.) As regards the possibility 

 of recovering this waste potash, Mr. Burrell found 

 that from the smoke-room of a club 9I oz, of ash 

 and unburnt tobacco could be collected in eight days; 

 from the lounge of a large hotel 13 oz. in four days ; 

 from a large restaurant 2^ lb. in ten days, and from 

 a music-hall (one-tenth part of the auditorium) 4 oz. 

 after one performance. The tobacco consumed in the 

 United Kingdom for the year ending March 31, 1914, 

 would give "approximately 13,359 tons of ash, contain- 

 ing 2672 tons of potash, which, at the pre-war price 

 of kainit, would be worth nearly 51,000^. 



In a paper read before the Federated Malay States 

 Chamber of Mines in March last, Mr. J. B. Scrivener, 

 geologist, discusses the situation in the peninsula 

 created bv the increased demand for tungsten. The 

 peninsula' is one of the chief world sources of this 

 metal, which nearly always occurs in the form of 

 wolfram— a mixed Von and manganese tungstate — 

 contaminated with tin-stone. To get new supplies 

 Mr, Scrivener concludes that two courses are open. 

 The first is to encourage prospecting in new land and 

 to do ever^^thing to encourage the Chinese miners 

 going into the less known parts of the granite ranges. 

 It is anticipated that it is unlikely that large quantities 

 of pure tungsten ores will be found, but that mixed 

 wolfram and tin-stone areas will be discovered. The 

 second course is to improve the facilities for the 

 magnetic treatment of this mixture with the separa- 

 tion of the wolfram. For this at present only two 

 plants exist, and much wolfram contaminated with 

 tin ore is lying idle because of the expense of sending 



' it for treatment. Scheelite (calcium tungstate), which 

 cannot be magneticallv purified, is in a different cate- 

 gory. It is certainly to be hoped that the Government 

 will do all in its po'wer to encourage the output of a 



• metal the usefulness of which, both for war and peace 

 purposes, is increasing every year. 

 NO. 2434, VOL. 97] 



The Revue ginirale des Sciences for May 15 con- 

 tains an article by M. Zach in which he gives formulae 

 for the strength of flat rectangular plates encastr^ at 

 the edges, and subjected to uniform pressure p. 

 These formulae are based on experiments made by 

 Bach, and by the Naval Departments in Germany and 

 the United States of America. The maximum bend- 

 ing moment occurs at the middle of the long edge of 



the plate, and is ^ if the ratio of breadth a to 



length b is greater than i : 3. The bending moment 

 at the centre of the plate has a value less than half of 

 this. For other ratios of a :b, the bending moments 

 at the middle of the long edge and short edge respec- 



tively are K^^ and K„^', 

 12 12 



wli 



K. and Kb are 



factors having the following values : — 



a : 6 I : 2 's 1:2 I : 1 '8 i : i '6 i ; i "4 i : i "2 1:1 



Kji 099 o'96 o"94 o"9i 086 079 064 

 Kb 003 006 009 014 o"22 o"38 0*64 



At the corners of the plate the bending moment 

 reverses in sign. The subject is of considerable im- 

 portance in connection with the design of bulkheads, 

 and we believe that the results of other experiments 

 which have been made in this country will be avail- 

 able shortly. 



Under the title, "A Scheme for the Promotion of 

 Scientific Research," a suggestive little volume by 

 Mr. W. B. Priest was published by Messrs. Stevens 

 and Sons, Ltd., Chancery Lane, London, E.C., in 

 1908 (see Nature, January 21, 1909, vol. Ixxix., 

 p. 345). The scheme is based on the Patent Acts, 

 and, according to it, any person who had made a 

 scientific discovery of a prescribed description could 

 apply for a grant of money, the application being 

 accompanied by a specification of the discovery. The 

 formation of the Committee of the Privy Council for 

 Scientific and Industrial Research has led Mr. Priest 

 to adapt his scheme to the work of this Committee ; 

 and he has sent us a copy of a communication made 

 bv him to the Advisory Council upon the matter. One 

 of the chief difficulties which the Council has to meet 

 is that industrial firms are unwilling to make known 

 valuable results of researches in their works without 

 adequate safeguards for the protection of their in- 

 terests. Mr. Priest shows in detail how his scheme 

 mav be used for this purpose, and we have no doubt 

 it will receive careful consideration from the Advisory 

 Council. 



OUR ASTRONOMICAL COLUMN. 



The Solar Activity. — The large spot group 

 (Nature, June 8) is again visible, and can be easily 

 seen with binoculars screened with smoked glass. 



Comet 1916a (Neujmin). — A possible connection be- 

 tween this comet and Encke's comet has been traced 

 by H. Svoboda. A comparison of their orbit elements 

 indicates that Neujmin 's comet originated in the path 

 of Encke's comet, possibly by a partition of the latter. 



The Shower of Perseid Meteors.— There is 

 evidence that the Perseids begin to appear during the 

 last week in June, and that the whole duration of 

 the shower extends over ten weeks. 



This year there will be a favourable opportunity for 

 making observations, the moon being only slightly 

 in evidence between June 25 and July 7. If any 

 streaking meteors are seen during this interval directed 

 from the region of Andromeda, near the stars 37 and 



