April 4, 1901] 



NA TURE 



537 



For a long time ornithologists have been hesitating 

 whether or no to include the tinamus of South America 

 in the same group as the ostrich-like birds ; but this 

 hesitating spirit does not commend itself to Mr. Pycraft, 

 who boldly says that the affinities between the two 

 imperatively forbid their separation. And it is this 

 innovation which leads him to reject the time-honoured 

 title, Ratitas. 



The inclusion of the tinamus in the group renders it 

 necessary to assume (even if we had not to do so on 

 other grounds) that the ancestors of the ostrich and its 

 kindred were formerly endowed with the power of flight. 

 Further, the author regards the group as a convergent 

 one, which has had a multiple origin from the common 

 avian stem before this began to split up into the more 

 specialised " Carinate " types. The cassowaries and 

 emeus are regarded as representing the most primitive 

 branch, which culminated, perhaps, in the more advanced 

 ostrich. From this it • apparently follows, although it is 

 not stated in so many words by the author, that the 

 divergence of the Ratites (to call them by their old 

 name), including the tinamus, took place while bird's 

 still retained teeth. While this may be so, it must be 

 confessed that some palseontological evidence in its favour 

 would be most welcome. 



It may be added that, according to the genealogical 

 tree given by Mr. Pycraft, the loss of the teeth in birds 

 must have taken place at a still later epoch, for we find 

 the cretaceous Ichthyornis branching off" long after the 

 divers and ducks had been differentiated. This seemingly 

 implies that the origin of the latter is to be carried back 

 to the Jurassic epoch, when, so far as we yet know, 

 Archseopteryx was the sole representative of bird life. 

 The author promises a supplementary memoir on Apteryx, 

 where he will, perhaps, explain how we are to get out of 

 this difficulty. 



A slight discrepancy between the aforesaid " tree" and 

 the text likewise stands in need of explanation. On p. 264 

 of the latter it is stated that the ostrich-like birds " are to 

 be regarded as polyphyletic — probably triphyletic," and 

 yet in the " tree " we find them arising from five distinct 

 branches. 



Space does not allow of allusion to the many interest- 

 ing observations on the osteology and pterylosis of the 

 group recorded by Mr. Pycraft, but these really form a 

 storehouse of information of the utmost value to future 

 workers. As he himself would doubtless be one of the 

 first to allow, opinions may legitimately differ in regard 

 to many of the conclusions arrived at by the author, but 

 as to the value of his investigations all opinion must be 

 in accord. R. L. 



OUR BOOK SHELF. 



Researches on the Past and Present History of the EartKs 

 Atmosphere. By Dr. T. L. Phipson. Pp. xii -H 194. 

 (London : Charles Griffin and Co., Ltd., 1901.) 

 In style and scope, Dr. Phipson's book reminds us of 

 essays submitted to the Smithsonian Institution for the 

 Hodgkins Fund Prize, and afterwards published in the 

 Smithsonian Report. A more or less popular description 

 is given of the atmosphere in its various relationships to 

 man, and in its meteorological aspects ; while in many 

 places short statements are made of observations and 



NO. 1640. VOL. 63] 



investigations carried out by the author himself. The 

 book should thus prove of interest to general readers as 

 well as to meteorologists and other students of science. 



In the early chapters, the thesis which Dr. Phipson 

 seeks to establish is " that the primitive atmosphere of 

 the earth was nitrogen, into which volcanic action poured 

 more or less carbonic acid and vapour, and that after 

 vegetable life appeared, free oxygen made its appearance 

 in the air, and has increased in quantity from those 

 primitive times to the present day." In connection with 

 the subject of the variations in the amount of carbon 

 dioxide in the air, it might have been well to refer to the 

 work of Arrhenius, Chamberlin and others on the effect 

 of variations in the proportion of the gas in air upon the 

 mean annual temperature, and past geological conditions. 



Dr. Phipson regards argon as allotropic nitrogen or a 

 carbide of nitrogen. The hydrogen gas driven off" from 

 meteorites when heated is, he holds, produced by the 

 decomposition of water vapour by the meteorite during 

 the passage through the air, or the absorption of water, 

 the oxygen of which combines with some of the con- 

 stituents of the meteorite when it is heated, thus setting 

 hydrogen free. He refers to the variation in brightness 

 of the star Algol as " still a mystery to astronomers," 

 though the spectroscopic work of Vogel has placed the 

 cause of variability almost beyond doubt. Like many 

 other writers who have not followed closely the physical 

 geography of recent years. Dr. Phipson believes in the 

 Gulf Stream myth, going so far as to commit himself to 

 the statement that "The mild climate of the British Isles 

 is very greatly due to this immense current of warm 

 water, without which we should be no better off, in this 

 respect, than people who live in the Arctic circle." To 

 understand how unfounded this statement is, we refer the 

 author to a paper in the U.S. Monthly Weather Review 

 of September 1900. 



In a short chapter on meteorites the remark is made, 

 " They are, no doubt, of the same composition as the 

 moon ; and are, I believe, minute satellites of our earth, 

 thrown off like our larger satellite was thrown off", in the 

 earliest stages of its existence." Here again we have 

 statements with little evidence to support them. Nothing 

 is known of the exact composition of the moon, so the 

 words "no doubt" in the sentence quoted are, to say the 

 least, gratuitous. 



While, therefore, we think the book contains an 

 interesting account of the earth's atmosphere, we suggest 

 that in several places statements are made as if they 

 were accepted conclusions, whereas they are often 

 opposed to the opinions of competent authorities. 



Catalogue of the Mesozoic Plants in the Department 

 of Geology, British Museum {Natural History). The 

 Jurassic Flora. I. 7 he Yorkshire Coast. By A. C. 

 Seward, F.R.S. Pp. xii + 341; plates xxi. (London: 

 British Museum (Natural History), 1900.) 

 Fossil plants from Gristhorpe Bay and neighbouring 

 parts of the Yorkshire coast are so widely distributed 

 among museum collections that Mr. Seward's descrip- 

 tive catalogue of them will be welcomed by many 

 museum curators in Britain and on the continent. But 

 the volume is more than a catalogue ; it is a history of 

 Oolitic plant-remains of Yorkshire, exemplified by the 

 fine series preserved in the British Museum. In addition 

 to the data provided by this material, the descriptions 

 are based upon specimens in many other collections 

 which have been examined and considered. As might 

 have been expected, the identification of type-specimens 

 was a difficult task, and in many cases it has been found 

 impossible to specify the type, which fact, remarks Mr. 

 Seward, " has afforded a practical demonstration of the 

 need of some system for the centralisation and cataloguing 

 of all specimens which have served for the diagnosis or 

 illustration of new species." 



