68 



NATURE. 



[September ig, 1912 



however, is even wider in its scope tlian the 

 "Natural History of Creation." The opening 

 lectures are devoted to a historical account of the 

 various hypotheses which have been formulated 

 regarding man's origin and evolution, and to the 

 bearing of Darwin's work on tlie modern problems 

 of anthropology. The follow^ing chapters have even 

 a wider sweep ; they deal with life, the conditions 

 of life, as far back in the world's history as human 

 imagination can reach. Embryology, growth, 

 anatomy, and all the various kinds of knowledge 

 which have even a remote bearing on the human 

 body are woven into the subject-matter of Prof. 

 Morselli's lectures. 



The chapters dealing with extinct and past 

 forms of men are very complete. One is rather 

 surprised to observe that he accepts in good faith 

 all the discoveries of ancient man which have 

 been made in South America in recent years. The 

 concluding lecture pictures the man of the future 

 as a form of Greek god. The numerous illustra- 

 tions, although they have often little connection 

 with the part of the text in which they appear, 

 are well executed, and have been selected from 

 many standard works and original papers. 



The work is so ambitious in aim and so wide 

 in its scope that it is impossible for any single 

 man to obtain a first-hand knowledge of all its 

 parts ; few could have completed so successfully 

 the task which Prof. Morselli imposed on himself. 

 An Outline of the Russo-Japanese War, 1904, 1905. 



Rv Col. Charles Ross, D.S.O. Vol. i., Up to, 



and including, the Rattle of Liao-Yang. Pp. 



xxv + 490+ 14 maps. (London: Macmillan and 



Co., Ltd., 1912.) Price los. 6d. net. (Military 



Text-Rooks.) 

 This account of the latest of the great cam- 

 paigns of modern history takes the story up 

 to the close of the first stage of the Japanese 

 advance into Manchuria, which was marked by 

 the complete and final severance of the field army 

 under Kuropatkin from the troops interned in 

 Port Arthur. 



Naturally in so comparatively short a work it 

 has been impossible for the author to enter into 

 any discussion of tactical problems or to refer to 

 the doings of the smaller units, whether in action 

 or during the various strategical movements of 

 the campaign. He has succeeded, however, in 

 giving a very clear view of the earlier phases of 

 the war, and of the numerous influences that 

 guided the actions of the opposing commanders. 



The chapters dealing with the war itself are 

 exceedingly clearly written, and the contrast be- 

 tween the divided counsels that confused the 

 Russian strategy and the impassive unanimity 

 that ruled the movements of the Japanese is well 

 brought out. As one would expect from an author 

 bearing the name of Ross, not only are the facts 

 clearly stated but the lessons to be learnt from 

 them are philosophically discussed. The book 

 should be read by all who desire to get a clear 

 view of the campaign, unencumbered by technical 

 detail, or to realise the effect on the art of war 

 of modern scentific advances. C. H. ,M. 



NO. 2238, VOL. go] 



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.] 



Practical Mathematics. 

 It is suroly rather a pity that Prof. Perry concluded 

 his letter with such a violent attack on the "profes- 

 sional mathematician." If he had attached a little 

 less importance to Sir William White's address and a 

 little more importance to the proceedings of, and 

 reports presented to, the Educational Section of the 

 Congress, I think he would find ample justification for 

 withdrawing, or at least qualifying, his statement 

 that the teacher "never studies his pupil," or that 

 "the poor average English boy is never studied by 

 the professional mathematician." 



One of the main changes that is taking place at the 

 present time consists in the introduction of the cal- 

 culus at a much earlier stage in our mathematical 

 curricula than was ever dreamt of fifteen years ago. 

 Surely this and many other equally important changes 

 owe their inception largely to what has often been 

 described as the " Perry movement." .After all, only 

 a small percentage of the boys who study mathematics 

 at school intend to qualify for the engineering pro- 

 fession. It is in connection with the education of the 

 large body of pupils who learn mathematics as part 

 of a general education that the introduction of the 

 practical element is producing the most beneficial 

 results. G. H. Bryan. 



Weather and the Ultra-violet Radiations of the Sun. 



I WAS rather astonished by Dr. Carl Ramsauer's 

 second letter in N.nuRE of June 13, w-hich has just 

 reached me, and although "the w'eather of 191 1 " is 

 rapidly becoming ancient history, and I have much 

 reluctance in pursuing the discussion of it, it is hoped 

 that the long distance which separates me from the 

 editorial room will be sufificient apology for asking 

 your indulgence at this late day in order to register 

 a protest against the conclusions enunciated in that 

 letter. 



I regret having to acknowledge that, to me, the 

 letter appears of the nature of a lucus a noil lucendo. 

 If Dr. Ramsauer advances as a theory, well sub- 

 stantiated by experiment, that ultra-violet solar radia- 

 tion is the chief source of condensation nuclei in the 

 atmosphere, and cites in support of his theory 

 diminished ultra-violet radiation and a hot and dry 

 summer, with clear skies, in the northern hemisphere 

 during 1911; and if, upon learning that, simul- 

 taneously with the existence of drought conditions in 

 the north, there was excessive precipitation in the 

 southern hemisphere, he can conclude that his theory 

 is thereby fortified, in fact, universallv confirmed, then 

 he surely owes it to science to support this conclusion 

 by convincing evidence. This should be some- 

 thing more than a mere supposition that the 

 aqueous vapour which diffused into the hot 

 summer atmosphere of the north, not encountering 

 in the free air proper vehicles (provided by solar ultra- 

 violet waves) for returning to the earth's surface, 

 thereupon rushed to tlie southern hemisphere, where, 

 in lieu of condensation nuclei provided by solar ultra- 

 violet waves, it was pleased to avail itself of the 

 facilities afforded by the ordinary laws governing 

 gaseous bodies in order to get back to terra firma. 

 .\ccording to what Dr. Shaw has written, it is evident 

 that the laws of gases operated with full vigour in 

 the northern hemisphere durinjj the summer of igii. 



If, as Dr. Ramsauer contends, ultra-violet solar 



