April 2':,, 1889] 



NA TURE 



603 



scribed. The southward direction of peninsulas is 



attributed to folding of the earth's crust, and to depres- 

 sion of the ocean floor, which has caused the water to 

 predominate towards the south, so that they are always 

 in relation to areas of depression. It will thus be seen 

 that, in simplicity of conception, largeness and continuity 

 of the ideas dealt with, amplitude and detail of the 

 knowledge and inductions brought together and corre- 

 lated, this work promises to be one of the most valuable 

 contributions to the history of the earth which we possess. 

 From the time when Godwin-Austen planned his work 

 on the ancient physical history of Europe which geology 

 supplies, data have been accumulating with a rapidity 

 which has made the task almost hopeless, of writing a 

 history of the earth's surface which should be at once 

 exact in details and large in ideas. But Prof Suess does 

 not so much trench on geological history, which can only 

 be told intelligibly when supported by masses of tech- 

 nical facts ; for hi5 aim is to impart vitality to learning 

 and teaching of those phenomena with which the geo- 

 grapher is concerned. It may be too much to say that 

 he attempts to do for the surface of the earth what Dar- 

 win did for the distribution and classification of life, 

 because so much had been previously contributed with 

 which his own work is in perfect harmony ; but we may 

 say that henceforth no geographical teacher can neglect 

 to place before his pupils the methods and results which 

 the author's work brings to his hand. And we may an- 

 ticipate that much as Lyell's treatise, the " Principles of 

 Geology," has laid the firm foundations of geological 

 thought and of scientific observation in geographical 

 science, so this treatise appears likely to mark a similar 

 epoch in the history of geography, becoming a guide to 

 its principles for students and readers. 



It is significant that it is the outcome of long expe- 

 rience, first as Professor of Palaeontology, then as Pro- 

 fessor of Geology, on the part of one who has given many 

 of the best years of his life to the endeavour to make 

 practical application of geological knowledge in improv- 

 ing water-supply and navigation of the earth's surface 

 which surrounds Vienna. The same thoroughness and 

 devotedness with which these earliest of his public works 

 were done are seen in this latest contribution to education ; 

 and we cannot but see that geography, as Prof. Suess 

 teaches it, is a science based upon the sciences which he 

 has himself professed, though expanding in its ultimate 

 developments to include that knowledge which the 

 naturalist and the observer of Nature record. Every 

 chapter is followed by a long bibliography, in which the 

 reader finds the more important original sources of in- 

 formation with which the writer has refreshed his 

 memory ; and the beautiful drawings and engravings 

 scattered through the volumes will be not less welcome 

 to the earnest student as presenting typical examples of 

 the geological foundations of geographical truths seen on 

 the earth's surface. H. G. Seeley. 



NATURAL INHERITANCE. 

 Natural Inheritance. By Francis Gallon, F.R.S. 

 (London : Macmillan and Co., 1889) 



IT is related that, when some boastful patriot was once 

 describing the trees in his country as so high that a 

 n:an could hardly see their tops, a stranger retorted ; 



" That is nothing to the trees in my country, which are 

 so high that two men are required to see the top of them ; 

 one man looks as far as he can, and the other begins 

 where the first stops." A similar division of labour 

 would be required in order to survey adequately the 

 imposing scientific edifice which Mr. Galton has con- 

 structed ; based as it is on a foundation of geometrical 

 reasoning, and culminating in the clouds of biological 

 hypothesis. The parts which are nearest to terra finna 

 are most within our ken. The mathematical foundation 

 and the structure which rests immediately thereupon 

 appear to us solid and elegant. The author has re- 

 stated the law of error in a form adapted to sociological 

 investigations. He says truly and happily : — 



" This part of the inquiry may be said to run along a 

 road on a high level, that affords wide views in unexpected 

 directions, and from which easy descents may be made 

 to totally different goals to those we have now to reach." 



Mr. Galton reads a useful lesson to statistical prac- 

 titioners, when he complains that they limit their in- 

 quiries to averages, without taking account of those 

 deviations from the average which are the subject of 

 the theory of errors. 



" Their souls seem as dull to the charm of variety as 

 that of the native of one of our flat English counties, 

 whose retrospect of Switzerland was that, if its mountains 

 could be thrown into its lakes, two nuis.-inces would be 

 got rid of at once." 



Mr. Galton is not dead to the charms of "normal 

 variability." Statistical theory illustrated by him becomes 

 in a high degree fascinating : 



" Not harsh and crabbed as dull fools suppose." 



He may well say : 



" Some people hate the very name of statistics, but I 

 find them full of beauty and interest." 



Some of his riders on the law of error may be interest- 

 ing even to physicists. The following problem is not so 

 familiar to astronomers, but that Mr. Gallon's solution 

 of it may deserve attention. Given three or four obser- 

 vations relative to an unknown quantity ; and again 

 another small group of observations made on some other 

 quantity by the same instrument or method of observa- 

 tion ; and so on, each of the different little groups not 

 in general comprising the same number of observations : 

 find from the residuals, or apparent errors, presented by 

 the respective groups, the true " probable error" incident to 

 the method of observation. Mr. Galton gives four solu- 

 tions of this problem, of which two involve data which 

 are special to his subject ; two may be described as 

 general. Neither of the latter coincides with the theo- 

 retically best possible method ; but the consilience of 

 their results with each other and with the other two 

 methods is interesting. 



We have worded the problems in terms of errors. 

 The form in which it presents itself to Mr. Galton re- 

 lates rather to the deviations of individuals from their 

 common type. He is determining the " probable error" 

 or dispersion of the heights of brothers compared with 

 their mean. It proves to be much less than the cor- 

 responding constant for the adult population generally. 

 The question arises in the course of an inquiry whether 

 the mean height of brothers and sisters deviates from 

 the general average of adults less than the height of their 

 parents. There is a little difii:ulty in stating the question 



