December 2, 1915] 



NATURE 



;67 



ihc manufacture of modern explosives. The 



icatment, therefore, is only of the slightest, and 



isequently the work is of little practical value 



the technologist, except as regards its biblio- 



iphy and patent-lists. At the same time, it is 



interest to the general reader or the student 



who wishes to gain an acquaintance with the 



characteristic features of some of the latest 



triumphs of applied chemistry, such as the utilisa- 



lion of atmospheric nitrogen and the synthesis 



<ir ammonia and nitric acid — new industries which 



<iie said to have rendered Germany independent 



of external supplies of nitrates as raw materials 



lor the manufacture of explosives, and which, 



whatever be their present position, are ultimately 



<lcstined to effect a revolution in chemical in- 



<lustry. 



The work, therefore, from its very incomplete- 

 ness, is necessarily only of passing interest, but 

 :i-- an essay pour servir it may be commended 

 10 those who, for any reason, are satisfied with 

 ;i superficial knowledge of the vast and enormously 

 important subject of which it treats. T. 



ALLIGATORS. 

 The Alligator and its Allies. By Dr. A. M. 

 Reese. Pp. xi + 358. (New York and London : 

 (r. P. Putnam's Sons, 1915.) Price 105. 6J, net. 



PROF. REESE, of West Virginia University, 

 is best known as an embryologist, and the 

 author of a memoir on the development of Alli- 

 i^ator mississippiensis, published a few years ago 

 in the Smithsonian Miscellaneous Collections, a 

 reprint of which, with slight additions, forms 

 about one-fourth of this book. When hunting for 

 embryological material in the swamps of Florida 

 the author has had many opportunities of study- 

 ing the habits of the alligator, and his interesting 

 observations are embodied in the chapter entitled 

 "Biology of the Crocodilia." The chapters on 

 the skeleton and on the nervous system are'partly, 

 those on the digestive, urogenital, respiratory, 

 and vascular systems mainly, by the author. The 

 (Inscription of the muscular system is a transla- 

 lion from the account in Bronn's "Thierreich," 

 which is here and there quoted as the work of 

 Hronn himself, the fact being apparently over- 

 looked that Prof. H. G. Bronn, the founder of 

 the well-known zoological encyclopaedia, "Die 

 Klassen und Ordnungen des Thierreichs," was a 

 palaeontologist who never busied himself with 

 reptHes, and died fully ten years before the rep- 

 tilian section was taken in hand by Prof. C. K. 

 Hoffmann, whose name is not even quoted in the 

 very carelessly compiled bibliography at the end 

 of the book under review. 

 NO. 2405, VOL. 96] 



A treatise of this kind must naturally be to a 

 certain extent a compilation, but it is regrettable 

 that /more care should not have been exercised 

 in selecting matter, and that the author should 

 not nave drawn directly from the best sources 

 instead of taking so much at second hand. As 

 an example, we would point out that the map of 

 the present distribution of crocodilia, copied from 

 the "Cambridge Natural History" is inaccurate 

 in one respect of first importance from the Ameri- 

 can point of view, viz., in the omission of croco- 

 diles from Florida, where they are well known 

 to exist in addition to alligators, as the author 

 himself admits on the very same page. Further, 

 tne book might have been made far more useful 

 to the wide circle for which it appears to be in- 

 tended by comments on the bearing of the facts 

 recorded on various zoological problems, such as 

 phylogeny, ethology, zoogeography, etc. ^^'hy, 

 for instance, is the question " ancestry " skipped 

 over in a few meaningless words, when quota- 

 tions from Huxley's classical memoir, only men- 

 tioned in the bibliography, and from the numerous 

 recent publications on Triassic reptiles, could 

 have been interwoven to make an interesting and 

 instructive chapter? The fact that the egg of the 

 alligator is laid containing an embryo, often of 

 considerable size, surely might have been the 

 opportunity for a brief allusion to the question of 

 viviparous and ovoviviparous reptiles and to the 

 intermediate degrees known to connect the latter 

 with the normal state in various lizards and 

 snakes. 



There was no necessity, in a book like this, 

 to enter into details on the various species of 

 crocodilians, but, as the subject has been in- 

 cluded, there is no excuse for leaving out four of 

 the most interesting types, viz., the Malay False- 

 gharial, Tomistoma schlegelii, the gharial-like 

 crocodiles, Crocodilus cataphractus and john- 

 stonii, and the alligator-like Osteolaemus tetraspis. 



G. A. B. 



PLANE SURVEYING. 



Surveying and Field Work: A Practical Text- 

 Book on Surveying, Levelling, and Setting- 

 out. By J. Williamson. Pp. xxii + 363. 

 (London: Constable and Co., Ltd., 1915.) 

 Price 75.* 6d. net. 



IN a very practical work the author gives a 

 comprehensive account of the methods em- 

 ployed in the measurement of the earth's surface 

 when comparatively small areas are concerned, 

 so that the portion dealt with may be considered 

 as being a horizontal plane. 



Chain-surveying is fully described, and is con- 

 veniently used to introduce the beginner to the 



