144 



NATURE 



[October 25, 191^ 



the factor correlating it with cancer. It must be 

 admitted that the array of facts and figures pro- 

 duced by Mr. Green entirely favours his main 

 proposition, and it is difficult to arrive at any 

 other conclusion. 



With considerable ingenuity Mr. Green applies 

 his hypothesis to explain the incidence of cancer 

 in certain occupations and in certain localities, and 

 attempts to formulate an explanaton as to how 

 sulphur compounds may give rise to cancer. Here 

 he is on much less sure ground, and this part of 

 the subject may well be left for the present. The 

 book is illustrated with maps and diagrams, and 

 is very readable and interesting. 



R. T. Hewlett. 



A German-English Dictionary for Chemists. By 

 Dr. A. M. Patterson. Pp. xvi+316. (New 

 York : John Wiley and Sons, Inc. ; London : 

 Chapman and Hall, Ltd., 1917.) Price 95. 6d. 

 net. 



Dr. Patterson has filled what has long been an 

 irritating lacuna in the average chemist's library. 

 Certain scientific and technical terms are by no 

 means easy to translate from the German, and 

 recourse to the dictionary usually available is 

 generally hopeless. The book under review 

 should therefore be eagerly welcomed by the 

 steadily increasing number of ybung chemists in 

 England and America and by those who, even if 

 they have already a good working knowledge of 

 the language, are occasionally at fault. Not only 

 is it a good general dictionary of the German lan- 

 guage, but it contains also a very complete col- 

 lection of chemical terms belonging both to the 

 pure science and to technology. 



The book is prefaced by a useful introduction 

 explaining, for example, the new official German 

 spelling, and giving a short but valuable account 

 of the special points of German chemical nomen- 

 clature and how they should be rendered into 

 English according to the rules of the London and 

 American Chemical Societies. It does not seem at 

 all unnecessary, also, that the author should point 

 out the danger of confusing chemical endings and 

 case-endings ; thus the student is often apt to 

 translate "ketone" by "ketone" instead of 

 "ketones. " 



Past participles, preterites, and present third 

 singulars of simple verbs are a very convenient 

 inclusion. 



The book is clearly printed, the German being 

 in roman type. 



Mathematical Papers for Admission into the 

 Royal Military Academy and the Royal Military 

 College, Fehriiary-July, 1917. Edited by R. M. 

 Milne. Pp. 32. (London: Macmillan and Co., 

 Ltd., 1917.) Price 15. 3d. net. 

 Mathematical masters who prepare Army candi- 

 dates for their entrance examinations will be glad 

 to be able to procure this year's questions in this 

 handy form, before they are incorporated later 

 in Mr. Milne's large volume of examination papers. 

 NO. 2504, VOL. 100] 



LETTERS TO THE EDITOR. 

 [The Editor does not hold himself responsible for 

 opinions expressed by his correspondents. Neither 

 can he undertake to return, or to correspond with 

 the writers of, rejected manuscripts intended for 

 this or any other part of Nature. No notice is 

 taken of anonymous communications.] 



Transparency of the Atmosphere for Ultra-violet 

 Radiation. 



It is well known that the solar spectrum, even when 

 observed from a mountain-top, so that there are fewer 

 than four miles of "homogeneous atmosphere" over- 

 head, does not extend so far as A 2900, however long 

 an exposure is given. It has further been long sus- 

 pected that absorption by ozone is the cause, as origin- 

 ally suggested by Hartley. Perhaps it may be claimed 

 that the recent work of Prof. A. Fowler and myself 

 (Proc. Roy. Soc, A, vol. xciii., p. 577, 1917) leaves 

 little or no room for doubt that this is the true ex- 

 planation. 



As a sequel to the work just mentioned, I have 

 photographed the spectrum of a mercury-vapour lamp 

 four miles distant, and found that it extends as fai' 

 as the line A 2536, and perhaps farther. This line lies 

 near the maximum intensity of the ozone absorption 

 band, and therefore ozone can have nothing to do with 

 the limit of the spectrum in this case. To reconcile 

 the two results, it is necessary to assume that there 

 is much less ozone near the earth's surface than at 

 high levels, a conclusion in agreement with the pub- 

 lished chemical determinations of atmospheric ozone 

 by Hayhurst and Pring. 



The distant mercury lamp spectrum showed a con- 

 siderable falling off of intensity in the region of short 

 wave-lengths, long exposures being required to bring 

 out A 2536, which is one of the brightest lines when 

 atmospheric absorption does not intervene. Such a 

 result is to be expected according to known data on 

 atmospheric scattering of light, apart from the action 

 of ozone. 



In this connection I may mention that I have suc- 

 ceeded in observing the scattering of light by pure dust- 

 free air in a laboratory experiment with artificial illu- 

 mination. Details of these investigations will be pub- 

 lished later. R.J- Strutt. 



Imperial College of Science, October 22. 



The Cure of the isle of Wight Disease in the Honey 

 Bee. 



The publication of Mr. S. H. Smith's advertisement 

 on p. 324 of the British Bee Journal for October 11, 

 in which he mentions "proflavine" and " acri- 

 flavine" as being efficacious in the treatment of Isle 

 of Wight disease, impels me to publish the following 

 account, which I original!}' intended to keep back until 

 further experiments had confirmed and extended the 

 results. 



On April 14 last I attended the annual meeting 

 of the Leicestershire Beekeepers' Association, to offer 

 my services in a full investigation of the Isle of Wight 

 disease, which I proposed should be undertaken with 

 the co-operation of the members. The meeting showed 

 the greatest appreciation of my offer, and those pre- 

 sent undertook to supply me with all the information 

 and help they could. 



Efforts were first directed to securing specimens of 

 diseased bees for investigation, but, owing to the fact 

 that I was unable to hear of any members who then 

 possessed affected stocks, I did not come into contact 

 with an actual case until July, 1917. In the meantime 

 I had been discussing the general properties of the 

 disinfectant flavine, which has been s'uccessfullv used 



