August ii, 192 i] 



NATURE 



741 



suitably, an account of mammalian digestion, but 

 this should be stated ; instead, it is said to be an 

 account of the physiology of digestion in general. 

 The respiratory movements in the frog are badly 

 •explained; if they took place as described, no air 

 would ever be expelled to the exterior, and the 

 animal would ultimately burst. Also the descrip- 

 tion of the frog's truncus arteriosus is not easy 

 to follow, and there is no explanation of how its 

 tnechanism works, and no statement that the 

 arterial arches contain blood of different degrees 

 of oxygenation. The author appears to distin- 

 guish ague from malaria ("three distinct diseases, 

 malaria and two kinds of ague ") ; while only the 

 maximum recorded length {36 metres) is given for 

 Taenia saginata, which is surely liable to mislead 

 the student as to its usual dimensions. 



The last chapter, which is so important, is too 

 •compressed ; the subjects of the forty-two pages 

 include evolution ; variation, heredity, and selec- 

 tion in connection with the Darwinian theory ; 

 Mendelism ; and palaeontology as illustrated espe- 

 cially by the reptiles ; while the topics of the 

 ■evolution of sex and its meaning do not appear 

 to find a place. Some of the figures introduced 

 from Bourne's "Comparative Anatomy of 

 Animals " have suffered considerably — e.g. those 

 of the nephridium of the earthworm and of the 

 skeleton of Scyllium ; they are unworthy of a 

 place in the book. 



Errors which have been noted are as follows : 

 A trochanter is a prominence, not a depression 

 (p. 30); to say that membrane bones are "formed 

 by bone tissue being laid down in a membrane " 

 is neither adequate nor correct. Among mis- 

 prints one might note' "Calkin," "Biitchli," 

 "Weissmann," "strobilla," "alteration" (of 

 generations), " aborizations " (p. 95), "coecum" 

 and "stomodoeum" for "caecum" and "stomo- 

 daeum," and " anistropic " (p. 42). " Pre-caval " 

 contains an unnecessary hyphen, while in 

 "sub-cutaneous" and " sub-clavian " it is more 

 than unnecessary. 



The author, in his preface, acknowledges his 

 indebtedness to Profs. Dendy and Hill, especially 

 to the latter, on whose lecture-notes parts of the 

 book are more or less directly based. 



The Analysis of Steel. 



The Chemical Analysis of Steel-Works' 

 Materials. By F. Ibbotson. Pp. viii -1-296. 

 (London: Longmans, Green, and Go., 1920.) 

 215. net. 



THE "Analysis of Steel-Works' Materials" 

 of Brearley and Ibbotson has long enjoyed 

 a reputation as a sound and trustworthy manual 

 NO. 2702, VOL. 107] 



of the subject with which it deals, and its con- 

 tents are familiar to most steel analysts. The 

 revision of the work has been undertaken by one 

 of the authors only, and advantage has been 

 taken of the occasion to extend the treatment of 

 steels, alloys, slags, etc., on the analytical side, 

 and to gain space for such extensions by omitting 

 the sections of the earlier work dealing with 

 pyrometry and the use of the microscope. In 

 the interval which has elapsed since the original 

 publication many books on these two subjects 

 have made their appearance, and their develop- 

 ment has been so rapid that it has become un- 

 desirable to attempt their treatment in the course 

 of a few short chapters in a work devoted mainly 

 to a different branch of the subject. Mr. Ibbot- 

 son 's experience of the analysis of steel-works' 

 materials is exceptionally wide, and the methods 

 which he describes have been in all cases person- 

 ally tested and compared with alternative pro- 

 cesses, so that the author may be accepted as a 

 safe guide, especially in the difficult region of 

 the analysis of high-speed tool steels and 

 other complex alloys containing the rarer 

 metals. 



The separation of the rarer elements has been 

 worked out with great care for the purposes of 

 mineral analysis, and it is possible, by following 

 somewhat laborious methods, to effect a complete 

 separation of the metals contained in a mineral 

 with a high degree of accuracy, as has been shown 

 more particularly by American work on the com- 

 position of rocks. The analysis of complex steels, 

 however, calls for processes which are rapid as 

 well as accurate, since the results are usually re- 

 quired for commercial purposes within the shortest 

 possible time. The high cost of the rarer alloy 

 metals makes their exact estimation very im- 

 portant, whilst certain alloy steels are remarkably 

 sensitive to minute variations in the proportions 

 of the added elements, so that to devise methods 

 which will yield, in the hands of the works 

 chemist, results of the required accuracy in a 

 reasonably short time is a task of some difficulty. 

 The author lays great stress on accuracy, so that 

 while his methods are not invariably the most 

 rapid, they are such as can be trusted where a 

 gain in speed might possibly be accompanied by 

 a serious risk of error. 



The work differs a little in its arrangement from 

 most text-books on the subject. The opening 

 chapter deals with certain reactions of a more or 

 less general character, including the separation 

 of iron from other metals, the reduction of solu- 

 tions by nascent hydrogen by means of the Jones 

 reductor, and the precipitation of chromium, 

 molybdenum, tungsten, and vanadium by means 



