35° 



NA TURE 



[August 9, 1906 



acid group which are required in large amounts for 

 cell repair, and that it is only the commoner amino- 

 acids which are not required in the amount usually 

 taken, and which are consequently so rapidly dis- 

 charged from the body. 



This example of the manner in which the puzzles 

 of metabolism are grappled with will be sufficient to 

 show the character of the book, and one hopes that 

 those interested in these fundamental questions will 

 themselves study in full wliat a reviewer is only able 

 to state imperfectly in barest outline or in samples. 



W. D. H. 



OUR BOOK SHELF. 



Poverty and Hereditary Genius; a Criticism of Mr. 



Francis Gallon's Theory of Hereditary Genius. 



By F. C. Constable. Pp. xvi+149. (London: 



Arthur C. Fifield, 1905.) Price 2s. net. 

 The criticism which Mr. Constable brings forward 

 in this book is that reputation is not a test of ability, 

 and as Gallon's theory of hereditary genius is based 

 on this assumption, it has to be discarded. The statis- 

 tical evidence given in " Hereditary Genius " has to 

 be explained away, and Mr. Constable attempts to 

 do this by what he calls the " swamping eftect of 

 poverty." We quite agree with Mr. Constable that 

 it is harder for a poor man with uninfluential parents 

 10 achieve success as a judge than for a rich one with 

 influence, but this does not seem to us to justify Mr. 

 Constable in discarding the conclusions of " Heredi- 

 tary Genius," for if the social conditions of both 

 parents and ofl'spring are relatively about the same, it 

 seems as if the omission of the ability in poverty- 

 stricken parents and their children is rather like leav- 

 ing out of account the addition of numbers to both the 

 numerator and denominator of a fraction. The 

 omission may therefore not affect the result at all, 

 and whether fuller statistical evidence should modify 

 Mr. Gallon's conclusions is a matter which can only 

 be decided by statistics other than those which Mr. 

 Constable discusses. He appears, however, to have 

 overlooked altogether in his argument that other 

 statistics exist and tend to show that psychical and 

 physical characteristics are inherited in the same way, 

 a point which seems to us to upset a good deal of 

 Mr. Constable's criticism. 



Mr. Constable does not refer to Mr. Gallon's other 

 books, and apparently quotes from the 1S69 edition 

 of " Hereditary Genius." It is a pity that Mr. 

 Constable does not always succeed in expressing him- 

 self very clearly, and his habit of putting his argu- 

 ments in the form of questions becomes somewhat 

 tiresome, and makes the book seem a rather dis- 

 jointed composition. 

 Modern Cosmogonies. By Agnes M. Gierke. Pp. 



vi + 287. (London : A. and C. Black.) Price 35. 6d. 



net. 

 This popular account of the structure of the universe, 

 so far as it can be understood with the means of 

 inquiry now at the disposal of astronomers, should 

 serve a useful purpose in directing attention to the 

 position of the most difficult problem of celestial 

 science. To earlv philosophers it was sufficient to 

 regard the heavens as a solid and crystalline firmament 

 in which the stars are fixed; facts of observation were 

 not considered essential for the metaphysical found- 

 ation upon which the great minds of antiquity sought 

 to support their universe. The ingenious framework 

 of solid concentric spheres and epicyclic motions was 

 shown to be a baseless fabric by Tycho Brahe's con- 



NO. 1 919, VOL. 74] 



siderations of the orbits of comets, and was finally 

 discredited by the law of gravitation. 



What may be regarded as the modern era of scien- 

 tific cosmogony, in which serious attempts were 

 made to explain what is seen on the background of 

 space, opened about a century and a half ago with 

 Wright's " cloven disc " theory of the Milky Way 

 and Lambert's view of it as a sidereal ecliptic. These 

 considerations of the nature of the universe are related 

 to those of its origin adumbrated by Swedenborg and 

 Kant as the nebular hypothesis, and afterwards 

 worked out in mathematical detail by Laplace. 

 During the past few years several objections of a 

 mathematical and physical nature have been raised 

 to this hypothesis, which has proved to be vulnerable 

 at many points. In Miss Gierke's words, " It has, 

 indeed, become abundantly clear that the series of 

 operations described by Laplace could scarcely, under 

 the most favourable circumstances, have been accom- 

 plished, and in a thin nebulous medium would have 

 been entirely impossible. The nebular cosmogony 

 has not, then, stood ' Foursquare to all the winds 

 that blew.' Its towers and battlements have crumbled 

 before the storms of adverse criticism. It survives 

 only as a wreck, its distinctive features obliterated, 

 although with the old flag still flying on the keep." 



Tidal evolution, the meteoritic hypothesis, and other 

 views developed in recent years to satisfy the de- 

 mand for a cosmogony consistent with existing know- 

 ledge of the heavens, particularly with spectroscopic 

 observations, are described by Miss Gierke. While 

 we cannot subscribe to all her judgments and inter- 

 pretations, her work contains a large amount of 

 material, both observational and speculative, and 

 general readers will find much to interest them in it. 



R. A. G. 

 The Geor)ietry of the Screw Propeller. By W. J. 



Goudie. Pp. 47. (London and Glasgow : Blackie 



and Son, Ltd.) Price is. 6d. net. 

 This is a small book presenting " a simple exposi- 

 tion of the geometrical principles connected with the 

 screw propeller, and illustrating the various ways in 

 which these may be applied to obtain a correct de- 

 lineation of the propeller on paper, in the drawing 

 office, and in the foundry." It is intended principally 

 for the use of engineering students in technical 

 schools, but is likely to prove useful in other direc- 

 tions, since it contains a clear and admirably illus- 

 trated account of the geometry of screw propellers. 



The writer is a lecturer on meirhanical engineering 

 in Paisley Technical College, and possesses a good 

 knowledge of workshop practice in addition to 

 thorough familiarity with the geometry of his sub- 

 ject. He does not attempt any discussion of the 

 design of a screw propeller most suitable for a new 

 ship, but restricts attention to the preparation of 

 drawings, patterns, and moulds required in the 

 manufacture of propellers for which the dimensions 

 and forms have been determined. This is a wise dis- 

 cretion, for while the geometry of screw propellers 

 admits of exact treatment, the selection of the most 

 efficient propeller for an individual steamship is even 

 now a matter not admitting of exact scientific treat- 

 ment when precedent has to be departed from ; experi- 

 ments alone can be trusted. 



Mr. Goudie describes in clear and simple language 

 the methods by which helical surfaces of uniform or 

 variable pitch may be constructed, and illustrates in 

 detail the practical methods of moulding the blades 

 in the foundry. For the benefit of students who may 

 not have the opportunity of actual work in the foundry 

 the author indicates how, with the aid of a few simple 

 tools and materials, skeleton models of the various 



