62 



NATURE 



[July 15, 1909 



relationship lies rather with the Veddahs of Ceylon 

 and the other straight-haired Proto-Dravidian races 

 that still exist sparsely in India and the Malay 

 Islands. " 



He says we have a good deal of information as to 

 their burial customs, which differ totally from those 

 of the Australians, and their language " seems to 

 have differed entirely from the Australian and to show 

 remote connection with the Andamanese " (p. 31). 



His last chapter discusses the biological relations of 

 Australia and Tasmania, and the evidence for the 

 connection of Australasia with Antarctica. He is 

 convinced that the fauna and flora of Australia 

 entered it from the south and not from Asia. As he 

 truly remarks, the marsupials are inost numerous 

 and of the most primitive types in southern Australia, 

 while they are comparatively rare and most specialised 

 in northern Australia. If they had migrated from 

 Asia the opposite arrangement would have been 

 expected. 



The author still accepts Galaxias as evidence of 

 the recent connection of Australasia and South 

 America; he admits that it visits estuaries, but con- 

 siders that it can only have spread across the southern 

 Pacific along the shelf around the Antarctic land. 

 After Mr. Boulenger's letter (Nature, 1902, vol. l.xvii., 

 p. 84), with its convincing evidence that Galaxias 

 breeds in the sea, the distribution of that fish is no 

 indication of a former land connection. One slip, in 

 fact, is the statement that the tree Senecios are 

 unknown in the tropics (p. 133). They are the largest 

 trees in the alpine zone of Kenya and other east 

 African mountains. The author represents Tasmania 

 as not a biological appanage of Australia, as he holds 

 that it^ acquired its present distinctive characters 

 before its separation from the mainland. Although 

 this view is probable, the striking differences which 

 the author well describes between the faunas of the 

 two areas indicate that the separation happened long 

 enough ago for many of the Tasmanian mammals to 

 have developed into new species. The most striking 

 part of the book is Mr. .Smith's valuable contributions 

 to knowledge of the primitive Tasmanian fresh- 

 water shrimps, of which he discovered a new genus. 

 They are allied to those of the European Carbonl 

 iferous Crustacea, and are one of the groups of 

 archaic animals still living in Australasia. 



PROPERTIES OF BUILDING MATERIALS. 

 Introduction to the Chemistry and Physics of Building 

 Materials. By Alan E. Munby. Pp. XX + 34S. 

 (London : A. Constable and Co., Ltd., 1908.) Price 

 6s. net. 



T TNLIKE many books intended chiefly as short 

 ^ cuts to success in examination, this work 

 seeks to impart in a clear, concise, and accurate 

 manner the scientific principles underlying the proper 

 use of material in construction. 



Part i. contains chapters devoted to natural laws, 

 measurement, the air, heat, chemical principles, 

 water, acids and bases, coal, and a useful outline of 

 geology. In part ii. all the chief building materials 

 are dealt with in detail. The origin and occurrence 

 NO. 2072, VOL. 81] 



of each material are described, also the preparation 

 for use, varieties met with, impurities and adulterants, 

 defects, and tests for quality, including both laboratory 

 tests and simple practical tests such as may be applied 

 by the workman. In every case the author is careful 

 to point out the application of correct scientific prin- 

 ciples, and from his practical knowledge is able to 

 suggest many useful tests not generally known. 



The work is thoroughly up to date, from both a 

 scientific and a practical point of view, and the latest 

 results of investigation into such matters as the 

 setting action of cement, the rusting of iron, and the 

 micrography of metals are clearly and broadly stated 

 in their bearings upon the practical use of material. 



This book will prove of great value to students in- 

 tending to take up architecture as a profession. The 

 builder, also, and the practical man will be glad to 

 take advantage of much of the information given. In 

 fact, many teachers in the architectural and building 

 departments of technical colleges will be glad to know 

 of the book with the view of recommending it to their 

 students. 



This being the first edition, it is hardly to be 

 expected that the book is entirely free from defects. 

 The diagrammatic illustrations given seem to be the 

 least satisfactory part of the work. While the work 

 has been written so lucidly as to render numerous 

 figures unnecessary, it would seem that more than 

 nine illustrations might be legitimately employed to 

 assist the reader in grasping the subject. There is 

 room for some improvement, too, in the chapter on 

 timber, several inaccuracies having escaped correction, 

 e.g. on p. .>95, what is described as decay due to 

 worms should rather be ascribed to the larvae of 

 certain beetles, &c. Also, on p. 296, the Teredo, 

 although popularly regarded as a worm, should really 

 be classed with the mollusca. In dealing with dry rot 

 on p. 294, the temperature conditions are not referred 

 to. although these play an important part in the 

 de\elopment of the fungus. 



A few statements in other parts of the book seem 

 to call for reconsideration or correction, e.g. p. 20, 

 § 3 : — " If two vessels containing the same liquid be 

 connected, the level in each will become the same 

 whatever ' the form or distance of the connecting 

 pipe." Again, the statement, p. 277, " Shearing and 

 torsional stresses are identical, apart from the method 

 of applying the force producing them," although 

 true, needs explanation to the mind not trained in 

 mechanics. 



The explanation given on p. 323 as to the optical 

 theory of the production of a green pigment from 

 yellow and blue powders, will hardly explain fully 

 how it happens that the same blue powder, mixed 

 with a red one, will produce purple. Turning to the 

 useful table on p. 63, the tyro may be puzzled again 

 to know why, if the substance denoted by CaO^Hj is 

 termed calcium hydroxide, the substance PbO^H^ is 

 termed lead hydrate; or, if COj is called carbon 

 dioxide, why SiO^ is called silicon oxide. On p. 18 

 the author correctly says, " To move a heliostat reflect- 

 ing a beam of light requires no more effort than would 

 be necessary in the dark," but the heliostat being 



^ Italics not author's. 



