189S] SOME NEW BOOKS 137 



■who desires to comprehend something of the work now being done on 

 variation, on selection, on specific differentiae, and so forth, or who may 

 even be bold enough to attempt some of these mathematical methods 

 himself, Mr Lupton's book will come as a godsend. The chapters on 

 [deas, i>n Reasoning, on Fallacies, on Laws of Nature, mi Cause and 

 Effect, and mi Observations and Experiments, with their references to 

 larger works, may be read with profit by many who think they were 

 taught all about such things at school. But it is when we get to the 

 explanation of such things as Units and Dimensions, Averages, 1 differ- 

 ences, Mensuration, the Use of Tables, Errors, Means, the Law of Error, 

 and Graphical Methods, that the special value of Mr Lupton's book 

 becomes apparent. There are many who will be glad to learn the 

 difference between an Average and a Mean, and more particularly to 

 know which of the various Means is the one now selected by mathe- 

 maticians as the Mean, while the difference between the Mean and the 

 Mode is another subject upon which light is needed by a good many 

 who are not so well acquainted with Prof. Karl Pearson's writings as 

 they ought to be. 



Nevertheless, valuable though Mr Lupton's book is, we should 

 greatly like to see a manual on the same lines, but more especially 

 adapted for the biologist. Nearly all Mr Lupton's are taken, as is 

 natural, from physics or chemistry; Prof. "Weldon and his crabs are not 

 so much as alluded to. But the construction of graphical curves to 

 represent biological observations presents difficulties and complications 

 of its own. The useful application of logarithmically ruled section- 

 paper was recently suggested by Mr D. J. Scourfield ; while readers 

 who are interested in the determination of species will find an inter- 

 esting application of mathematical methods suggested by Prof. C. B. 

 Davenport in Science for May 20. We merely mention these papers 

 as examples of the kind of thing that might well be incorporated in a 

 text-book of biological mathematics, and we can but regret that so use- 

 ful a person as Mr Lupton has been lost to our own branch of science. 



Historical Specimens of Fossil Cephalopoda 



List of the Types and Figured Specimens of Fossil Cephalopoda in the 

 British Museum (Natural History). By G. C. Crick. 8vo, boards, pp. vi + 104. 

 London. 1S98. Price, 2s. 6d. 



To the serious worker who is called upon to identify organisms nothing 

 is more helpful, and in critical cases essential, than a comparison with 

 the specimen <>n which the original description was based; and to 

 such persons there is no mure welcome aid than a directory of these 

 so-called type-specimens. As regards the British fossils, a Committee 

 of the British Association has long been collecting information with a 

 view to such a list, and owing to its exertions several museums (among 

 others, those of Cambridge, Manchester, and York) have printed and 

 published lists of their type fossils. 



The present catalogue enumerates somewhere about 1000 speci- 

 mens (a striking illustration of the wealth of the British Museum) 

 with full references to the places where they have been described and 

 figured, as well as to their locality and stratigraphical horizon. 



They are arranged alphabetically according to the generic names 



