206 



KNOWLEDGE. 



[September, 1901. 



lines of work t<j other experimenters. For instance, the resistance 

 t(j the suction of water in pipes, and the study of 

 Huid motion by means of coloured bands, formed the subjects 

 of detailed papers by him in 1883 and 1893 respectively ; and 

 it is worth while to read thesei papers in connection with later 

 ones by other authors on related subjects. Another instance 

 is the long report on experiments made to determine the action 

 of waves and currents on the beds and foreshores of estuaries by 

 means of working models. As an example of a scientific in- 

 vestigation, carried on with all the refinements of modern 

 methods, we may mention the determination of the mechanical 

 equivalent of heat, described in the Bakerian lecture of the 

 Royal .Society in 1897. These are only rough indications of 

 the" contents of the volume, but as " good wine needs no bush," 

 so Prof. Reynolds's work does not require advertisement in the 

 scientific world. It will live to please and inspire generations 

 of students of science. 



" The CROcoDrLi.iNs, Liz.\rds, and Snakes oe Nobth 

 America." By Prof. E. D. Cope. Pp. 1294. Plates 36. 

 (Washington; U.S. N^ational Museum. 1900.)- This ijosthumous 

 «ork of Prof. Cope forms practically the whole of the Report 

 of the U.S. National Museum for 1898, and is an important 

 monograph on the scaled reptiles of North America. The geo- 

 graphical scope is the Nearctic geological realm, and the work 

 constitutes the first general account of the North American Sauria 

 or Lacertilia since that of Holbrook in 1845, and the only one 

 on the Ophidia since the book of Baird and Girard, published 

 111 1853. With the exception of a few pages the present memoir 

 IS naturally taken up with the lizards and snakes of these groups, 

 which are" with sufficient justification arranged in one order 

 — ^Squamata. Taking the lizards as a centre, it is suggested 

 that tbree series can be distinguished proceeding from the 

 midtiplicity of forms exhibited by them — namely, one towards 

 the serpents by the subterranean lizard, Aniphisbaena, found 

 in the warmer parts of South America., one to the partially 

 degraded type of the Geckos, and lastly through the highest 

 series to Chamseleons. This relationship, however, is open to 

 objections, and is not likely to be approved by all herpetologists. 

 The order Lorieata, including alligators and crocodiles, appeared 

 in Triassic time, and has continued up to the present day. 

 The genus Alligator is. however, of much more modern origin 

 than Crocodilus, no undoubted extinct .species having been dis 

 c-overed. The Alliflafor mississippiensis i.s the only species found 

 in North America, one of the two other species of the genus 

 occurring in China, while the habitat of the third is unknown. It 

 appears that the alligators of North America cannot long escape 

 extermination, and that the price of hides has gone up on 

 account of the scarcity of the reptiles. The only crocodile 

 described is Crocodilus am erica nus, though, unlike alligators, 

 crocodiles are found in Africa, Southern Asia, and North 

 Australia. The crocodile also dift'ers from the alligator in its 

 preference for salt water, and in being more vicious. 



" The Use of Words in Reasoning." By Alfred Sidgwick. 

 (A. & C. Black.) 7s. 6d. net. — A little logic is a dangerous 

 thing, especially if it is the scholastic form of logic which is 

 obscured with formalities. Opposition to this formal logic is one 

 characteristic of Mr. Sidgwick's book ; and there is no doubt 

 that his objections require consideration from the schoolmen. 

 Logic as oft«n studied for examinational purposes is itself illogical ; 

 for it involves the acceptance of definitions and doctrines which 

 do not admit of rigid proof. This, however, is a failuig of 

 text-books of other subjects. What Mr. Sidgwick urges is 

 that logic resembles the natural sciences in being i.irogressive 

 a,nd full of problems only partly solved ; and tliat the student 

 should recognise this in taking up the subject. In otlier words, 

 the student of logic should from the commencement ho encouraged 

 to view the subject in an inquiring frame of mind, even as he 

 would such .subjects as [ihysics and chemistry in schools, where 

 the "heuristic" method was followed. We" are, of course, in 

 .sympathy with Mr. Sidgwick's aims, but iit the same time we 

 must remark that, like other logician.s, he seems (o labour much 

 tfiat it obvious to the ordinary person. 



"Twentieth Century Inventions: A Forec.^.st." By 

 George Sutherland, m.a. (Longmans.) 4s. 6d. net.— Man, it is 

 often said, is distinguished from all other mammalian verte- 

 brates by his power of looking before and after. Nothing 

 is more fascinating than to compare the present conditions of 

 life with those of former times, and it is natural lliat after 

 such retrospective glances the min.l should proceed uncon- 

 .sciously to state a simple proportion— if during the last hundred 

 years the world has seen sucli and such advances, what m.ay 

 be expected, taking the same rate of )jrogressi<m for granted, 

 during the twentieth century? And what are tlie signs of the 

 coming of these improvements destined to revolutionise human 

 relations? Such is, expressed in its sini]>1est teiins. the problem 

 which Mr. Sutherland sets himsilf to .solvi'. liut. unfortunatelv 



for the correctness of their results, there is a disturbing factor 

 in the computation, which these prophets are apt to ignore. 

 In passing from the known to the unknown in a diagnosis of 

 the future it is beyond human power to allow for the un- 

 expected, yet the unforeseen discovery has taken the mo,st 

 important part in nineteenth century advances. The most far- 

 seeing man of science, with an unequalled endowment in the 

 way of scientific imagination, trying in 1801 to probe the 

 mysterie.s of the future could not have foreseen, for instance, 

 even " through a glass darkly," the development of spectrum 

 analysis in astronomy. So that the prophet is doomed to iiartial 

 failure. There is, however, much usefid work left for him, 

 and this possible task of indicating the probable direction of 

 the earlier improvements of the twentieth century has been 

 attempted with much skill and considerable success by Mr. 

 Sutherland. From the point of view of an ordinary cultured 

 reader, with no knowledge of a technical kind, the author has 

 indulged, perhaps, too much in detail, especially in the first 

 two or three chapters, in which the sources and storage of 

 natural and artificial power are examined. In some other sections, 

 on the other hand, data are provided sufficient for the justifi- 

 cation of several delightful glimpses of, to name an example or 

 two, life at sea and the home circle in fifty years' time. His 

 intimate knowledge of the inventions and discoveries of the 

 last century has enabled the author to produce an entertaining 

 book which should soon have a large number of interested readers. 

 " The Microscope and its Revel.\tions." Eighth Edition. 

 (Carpenter.) Edited by the Rev. W. H. Dallinger, D.sc, D.C.L., 

 LL.D., E.R.s., etc. "817 illustrations in the text, 23 plates, 

 1136 pages. 8vo, cloth, 28s. ; half calf, 32s. (J. & A. 

 Churchill.) — The appearance of a new edition of this standard 

 work on the microscope and its many branches is particularly 

 welcome, for it enables a comprehensive survey to be made of 

 the progress that has been effected during the last few years in 

 both optical and mechanical departments, and indicates the 

 pressure that modern research has brought to bear on manu- 

 facturers, causing them to do their utmost to satisfy the needs 

 of workers. In a former .edition of this work — the seventh — 

 the editor, the Rev. W. H. Dallinger, condemned in no uncertain 

 language, the microscope known as the Continental Model ; and 

 laid down broad but sensible lines for the building of the stand 

 that was to meet the demands of the various workers of the 

 future. It was in that edition also that a strong plea was urged 

 on behalf of the condensers having large aplanatic apertures and 

 for increased accuracy in manipulation generally. A reference 

 to the new edition of the Work shows how accurate were the 

 author's opiinions and recommendations, and they were un- 

 doubtedly no inconsiderable factor in the general improvement 

 that has" since taken place in the design, and accuracy of action, 

 of the best microscopes of to-day. This is revealed in the pages 

 of the new volume, for many of the microscopes therein figured 

 and described as types have been designed since the last edition 

 was publi.shed, and owe their origin in some measure to the 

 strong expressicuis of opinion then made. The present volume 

 gives a clear exposition of knowledge and theory regarding the 

 microscope ; and although much of the text is to be found in 

 the former edition, there are many new and re-written portions 

 which add to the value and lucidity of the book. The reviews 

 of the products of the various opticians are generous and fair, 

 and will bo found useful to those who need advice in the choice 

 of apparatus. It is a matter for regret that the publishers have 

 not seen their way to issue the book in two volumes — one devoted 

 to the microscope and its optical fittings, and the other to the 

 various branches of research with which it is associated. Many 

 workers woidd require only the first part, while the second 

 would appeal to general readers as niucli as to microscopists. 

 In its present form it is rather a bulky book, especially for 

 those who arc resident abroad or travel with their microscopes. 

 A little error concerning cover glasses has been perpetuated in 

 the new volume, page 439. Not only are the thicknesses given 

 for the three grades of cover glasses less than can be regularly 

 obtained, but the thinnest covers are universally known as No. 1, 

 the medium ;u> No. 2, and the thick as No. 3, whereiis the 

 reverse order is there given. Also the price of a s in. .82 N.A. 

 objective on page 574 given as £5 should be 50s. The book is 

 well printed, the illustrations carefully prepared and well dis- 

 played, and the book is one that will be found invaluable as a 

 text book to all microscopists. 



"Disease in Plants." By H. Marshall Ward, .sen., f.r.s., 

 etc. (Macmillan.) 7s. 6d. — Prof. Marshall Ward has given us 

 a useful and practical study of the general life of plants, and 

 the causes and effects of the various forms of disease to which 

 they are subject. The book is written essentially with the 

 view of helping the cultivator — whether forester, vine-grower, 

 or grower of roofs or cereals — to understand the general facts 

 of plant-life, the relation of plants to their environment, a.nd 

 the nature and symptoms of the various maladies to which they 



