NA TURE 



[November i8, 1909 



■pair laterally during the prophase of meiosis, and he 

 discounts the speculations which have been based on 

 mitochondrial and such-like cytoplasmic structures. 

 As regards the interpretation of the nuclear trans- 

 formations which occur during meiosis, Prof. Stras- 

 burger admits that he is influenced by theoretical 

 considerations in arriving at his final conclusions. 

 The views he advocates are not shared by all 

 investigators, although at the present time they are 

 rather widely supported. But the available evidence 

 is hardly sufficient as yet to allow of the matter 

 being brought to a decisive issue, and, indeed, the 

 very same preparations have been differently inter- 

 preted by the e.\ponents of the divergent views. It is 

 a pity, perhaps, that this should be so, but it is clearly 

 not an unhealthy condition of affairs when the final 

 conclusion on a question of fact is confessedly 

 influenced by other than objective evidence. 



The reader will find many other topics treated in 

 this volume by a master hand. Evidence is given to 

 sliow that the hybrid Fragaria virginiana x F. 

 ■clatior, which in the F, generation so exactly re- 

 sembles the latter (male) parent that its hybrid nature 

 has been doubted, does really arise in this way, but 

 ^hat the Elatior parent is completely dominant. 

 Alternation of generations is touched upon, and the 

 'bo;>k ends with a suggestive speculation as to how 

 the details of nuclear structure, and in particular the 

 ■meiotic divisions, have come to exhibit so close a 

 resemblance in the higher plants and animals respec- 

 tively. It is pointed out that so remarkable a fact 

 'cannot be otherwise than pregnant with real signifi- 

 'cance, especially when we reflect that we seek in vain 

 ■amongst the more primitive animals and plants for the 

 \miforniity which on a priori grounds we might, 

 perhaps, have anticipated would be found. 



It is impossible, in bringing this notice to a close, 

 to refrain from expressing appreciation for the manner 

 in which Prof. Strasburger has handled the more con- 

 troversial matter in his book. The invariable courtesy 

 with which he treats the opinions of those who happen 

 to differ from himself might well be copied bv some 

 •who still appear to imagine that scientific discussion 

 should be conducted on the lines of modern politics. 

 "Not the least of the qualities which have endeared 

 Prof. Strasburger to a wide circle of friends, in addi- 

 tion to that scrupulous fairness and consideration 

 ■^vhich he always shows to others, is the open-minded- 

 ■ness with which he is always ready to accept the result 

 of new discoveries, even when, as he himself says, 

 they may involve the sacrifice of long-cherished views. 



J. B. Farmer. 



METALLIC ALLOYS. 

 Lecons siir Ics AUiages metalliques. Bv Prof. J. 

 Cavalier. Pp. xix + 466. Illustrated. (Paris: 

 \uibert et Nony, 1909.) 



DURING the last twenty years a systematic study 

 has been undertaken of the properties of alloys, 

 their chemical nature and constitution, and the re- 

 lations between that constitution and their useful pro- 

 perties. The work has been made possible bv the 

 invention of trustworthy pyrometers, by the applica- 

 KO. 20Q0, \OL. 82] 



tion of microscopic examination to opaque substances, 

 and by advances in the knowledge of chemical 

 equilibrium. The investigations have in many cases 

 been carried out with an industrial aim, but by throw- 

 ing light on the chemistry of solid bodies they have 

 contributed largely to the development of pure science. 

 It is true that the whole subject is still to some extent 

 in a state of flux, and much remains to be done in 

 order to explain apparent contradictions, and to remove 

 the uncertainty and provisional nature of some of the 

 conclusions. Nevertheless, it is time to make the 

 fundamental principles of the science of alloys part of 

 the course of training of students of general chemistry. 

 Prof. Cavalier's book shows a pronounced superiority 

 for this purpose over previous attempts, and is one of 

 the manuals which teachers of chemistry may usefully 

 place in the hands of their students. It is based on 

 a series of lectures delivered by the author at the 

 University of Rennes, and is characterised by clearness 

 of thought and of language, logical arrangement, and 

 perfection of balance. 



The first part of the book contains a brief general 

 description of the methods of preparation and study of 

 alloys. Ordinary chemical analysis is not dealt with, 

 but proximate analysis, and the still more important 

 methods of microscopic metallography and thermal 

 study are discussed, and the physical and mechanical 

 properties are also considered. The treatment is 

 elementary, and is hardly full enough to help those 

 engaged in research, but it is sufficient for students 

 to obtain some knowledge of the methods of deter- 

 mining the constitution of alloys. No attempt is made 

 to set up a complete classification of alloys based on 

 their constitution, but perhaps this need not be re- 

 gretted when the artificial aspect of some of the 

 previous attempts at classification is remembered. 



The second part of the book contains the special 

 study of certain alloys, and is intended to show by 

 concrete examples how the general methods have been 

 applied in practice, and what results have been ob- 

 tained. There is no attempt to make this part com- 

 plete by describing all alloys, the author referring the 

 reader to Guillct's book, "Les Alliages metalliques," 

 published in 1906, for details of those alloys which 

 he has omitted to mention. However, Prof. Cavalier 

 has chosen his examples from alloys presenting some 

 industrial interest, and has passed in review most of 

 the important groups. He has contented himself 

 with a single example of each case met with in a 

 systematic study, arranging his material as far as 

 possible in the order of increasing complexity. Thus 

 the simple case of alloys of gold and silver is taken 

 first. The more complicated diagrams of equilibrium 

 assigned to lead, tin and antimony are next dealt w^ith, 

 and these are followed by the brasses and bronzes, in 

 which so many solid solutions occur. The relation 

 between constitution and useful properties find a 

 striking e.xample in the antifriction alloys, and the 

 iron-carbon alloys, of which the practical importance is 

 fundamental, present difficulties in their study owing 

 to the existence of a labile system, and are taken last. 



In the section devoted to special steels the method 

 of describing only a few typical alloys is discarded, and 

 a catalogue of the steels is given with their com- 



