May 9, 1907 J 



NA TURE 



suggestions which are incompatible with the moral 

 sense of tlie subject are in most cases at once re- 

 jected. Nevertheless, it must be admilted that if it 

 is possible bv means of hypnosis to suggest crime 

 to a person whose moral sense is defective, then this 

 is a factor which might become of vast importance 

 if hypnotic suggestion ever became a remedy of 

 general use. 



The author gives an interesting chapter on 

 "suggestive therapeutics," and in it he shows the 

 pov\er of suggestion of one mind upon another, and 

 even in the same person the influence of the con- 

 scious mind upon the subconscious. He believes 

 that Christian science is largely a system of auto- 

 suggestion. 



Dr. Ash strongly urges that there should be intro- 

 duced into the medical curriculum a compulsory course 

 of psvchologv and lectures on the principles of " sug- 

 gestive therapeutics." \\"e cordially agree with the 

 former recommendation, for it is lamentable to find 

 the ignorance that still exists regarding the normal 

 mind, and some knowledge of this subject is a 

 matter of growing importance, both from the 

 evolutionary and dissolutionary standpoints. 



For those who wish to learn some of the practical 

 points regarding hypnosis and suggestion. Dr. Ash's 

 book will be found most helpful, for although 

 it is small it contains much information. 



Domaiiie de Terviieren — Arboretum — Types dc Forets 

 des Regions tempdrees represeiitds dans leur Com- 

 position caractiristique. By Ch. Bommer. Pp. 

 211. (Brussels : Imprimerie F. and L. Terneu, 

 1905-) 

 The site of the above arboretum was generously 

 given by the King of the Belgians to the people. At 

 the time of the gift His Majesty expressed the opinion 

 that it was very useful, not to say indispensable, to 

 create or to preserve open spaces with natural decor- 

 ation near large towns, both from an jesthetic and 

 hygienic point of view. M. Ch. Bommer was 

 entrusted with the task of laying out the arboretum, 

 and this he has evidently done in a scientific and 

 practical manner. The various plots or groups have 

 been formed to illustrate the principal types of vegeta- 

 tion in the temperate zone of the old and new 

 worlds. Even the bushes and herbaceous plants 

 characteristic of these zones have been added to com- 

 plete the picture, thus very clearly illustrating the 

 characteristics of the various species and their geo- 

 graphical distribution. The arboretum also forms an 

 excellent centre for testing the acclimatisation of 

 exotic trees. We have also in the above book a de- 

 tailed account of the individual species which includes 

 synonyms, size, habit, general characteristics, and 

 uses of wood, &c. Numerous photographic plates are 

 included illustrating various groups and points of 

 general interest. Plans of the arboretum and maps 

 showing the geographical distribution of the species 

 are given at the end of this very useful and interest- 

 ing book. 



Elementary Science for Pupil Teachers. Physics 

 .Section by \V. T. Clough. Chemistry Section by 

 A. E. Dunstan. Pp. vi-l-183. (London: Methuen 

 and Co., 1907.) Price 2S. 

 Pupil teachers who have opportunities of doing 

 practical work will, if they perform the experiments 

 in this book and follow the guidance it gives, obtain 

 sound preliminary ideas of physics and chemistry. 

 The physics section comprises the measurement of 

 lengths, areas, volumes, and masses, simple hydro- 

 statics, and an introduction to the studv of heat. 



The chemistry section covers the subjects arising 

 from a careful study of air, water, and other common 

 substances. The volume is on the whole attractive, 

 but the smaller of the two types is likely to try the 

 eyes of readers. 



A First Geometry. By \V. M. Baker and A. A. 



Bourne. Pp. viii-f- 128-I- vi. (London: George Bell 



and Sons, 1907.) Price is. 6rf. 

 With the exception of a dozen theorems at the end, 

 this book is a simple course of experimental geo- 

 metry designed to familiarise young pupils with 

 fundamental geometrical conceptions by setting them 

 to draw with matliematical instruments and to con- 

 struct simple models for measuring angles and con- 

 structing plans. The lessons are interesting, and 

 ai ranged in a manner that shows the authors to be 

 well acquainted with the needs and capabilities of 

 beginners. 



LETTERS TO THE EDITOR. 



[The Editor docs not hold liinisclf responsible for opinions 

 expressed by his correspondents. Neither can he undertake 

 to return, or to correspond witli the writers of, rejected 

 manuscripts intended for this or any other part of Nature. 

 No notice is taken of anonymous communicatious.'\ 



Radium and Geology. 



Prof. Joly's interesting discovery (Nature, May 2, 

 p. 8) that typical rocks in the .Simplon Tunnel contain 

 quantities of radium considerably in excess of the average 

 of igneous rocks raises a question. From Mr. Strutt's 

 investigations it appears that the average content of 

 igneous rocks would be sufficient to account for the 

 ordinary temperature gradient in the earth's crust were it 

 due to radium. It seems, therefore, that, if the tempera- 

 ture was so caused, the gradient in the Si-mplon Tunnel 

 ought to have been higher than the average, viz. 1° F. for 

 between 50 feet and 60 feet. But, in fact, as beneath other 

 mountains, it was considerably lower. In Nature, October 

 27, 1904, it is stated that the temperature of the rocks in 

 tlie advanced gallery was 108° F. where the cover was 

 7005 feet. This gives 1° F. for q2 feet. In the St. Gothard 

 Tunnel it was 1° F. for 102 feet, and In the Mt. Cenis 

 Tunnel 1° F. for 100 feet. That the gradient in the 

 Simplon Tunnel, though low, was somewhat higher than 

 In the other two was probably caused by the spring 

 23° hotter than the rock, which brought up heat from 

 a lower level. I think I have shown In my " Physics of 

 the Earth's Crust," chapter xv!., that these low gradients 

 can but very slightly bo attributed to the convexity of 

 the surface. 



Is not, therefore, the result of Prof. Joly's examination 

 of the Simplon rocks rather unfavourable than otherwise 

 to the hypothesis that the heat of the earth's crust Is due 

 to radium? O. Fisher. 



Graveley, Huntingdon, May 4. 



Ethnological Notes on the Aboriginal Tribes of New 

 South Wales and Victoria. 



A REVIEW of the above work appeared in Nature of 

 May 31, 1906 (vol. Ixxiv., p. 100), to which I wish to 

 reply briefly. The review opens by saying that my works 

 " have either been Ignored or dismissed in a footnote by 

 experts such as Dr. Howitt and Prof. Spencer." Whilst 

 the reviewer was quite aware of the obscure " footnote," 

 he was quite silent regarding my reply to It, dated 

 June 27, 1905.' The opinions of the two men named dc^ 

 not perturb me, but when such an injurious statement 

 appears in the " thunderer " of scientific journalism, T 

 crave fair play and the right of reply. 



1 The Queensland Geographical Journal, vol. xx., fp. 73-75. 



NO. T958, VOL. 76] 



