Revietvs — Henry R. ITiiipe — Evolution in the Past. 269 



The probability therefore is that the figure for the viscosity of 

 glacier ice taken by Kelvin was somewhat too low ; but, as the volume 

 of ice passed is proportional to the cube of the thickness of the glacier, 

 even if Kelvin used 6 X 10'^ for the viscosity, the thickness of the 

 glaciers as calculated by him would only be too small in the proportion 

 of 1 to y 21 or about 1 to 2-76. 



I am indebted to Mr. P. H. Parr for some suggestions with regard 

 to calculations of Main's experimental results. 



120x10^2 

 100 X 10'2 

 80 X 1012 

 60 X 10^2 

 40 X 10^" 

 20 X 1012 



Tempbkatube C. 





2° 



4° 



6° 



IR.IHl'VIEI^VvT'S. 



I. — EvoLTJiTON IN THE Past. By Henet K. Knipe, F.L.S. 4to, 

 10 by 7-| inches ; pp. xvi, 242, with 56 full-page plates and 4 text- 

 figures. London: Herbert & Daniel, 1912. Price 12s. 6d. net. 



rriHE above is the title of a new work published this year by the 

 X author of Nehula to Man, which appeared in 1905. Like its 

 companion this volume is very fully illustrated by fifty-six full-page 

 plates in black and white, fifty being the work of Miss Alice E. 

 Woodward and six by Mr. Ernest Bucknall ; but, unlike its predecessor, 

 the present work is written in prose. 



There is a small, but increasing, section of the reading public to 

 whom the purely popular or the purely technical treatment of 

 a subject alike give little satisfaction. And on some subjects, among 

 which palaeontology might perhaps be included, literature can hardly 

 be found outside these two extremes ; therefore a debt of gratitude is 

 certainly owed to Mr. Knipe for so ably supplying a distinctly felt want. 



Furthermore, to many people dry bones, even when exhumed after 



