DISCOVERY 



135 



Reviews of Books 



M.Sc. 



The Evolution of Climate. By C. E, P. Brooks, 

 F.R.Met.Soc. (Benn Bros., Ltd., 8s. dd.) 



This book gives an account of tlie principal changes 

 of climate which have occurred upon the earth, from the 

 earliest remote ages down to and including historic times. 

 It may be a shock to many to learn that there was more 

 than one Great Ice Age ; in fact, there were several. 

 " One of the oldest known sedimentary rocks is glacial 

 in origin, and indicated the presence of an ice-sheet at 

 a very early stage in the earth's history. This is a 

 ' tillite ' or boulder-clay discovered by Professor Coleman 

 at the base of the Lower Huronian (Early Proterozoic) 

 of Canada. It extends in an east and west direction 

 for I, ooo miles . . . " (p. 32). Another Ice Age occurred 

 just after the Coal Period, when the lost continent of 

 Gondwanaland connected Africa, Asia, and Australia, and 

 when the North Pole was in the Pacific Ocean. Before 

 the onset of the last Ice Age, in which we live, there was 

 a spell of " remarkably mild and equable climatic con- 

 ditions extending into comparatively high latitudes, so 

 that the west coast of Greenland, for instance, had a 

 flora of almost sub-tropical aspect ..." (p. 42). It 

 is with the last Ice Age that Mr. Brooks is chiefly con- 

 cerned. He accepts, with reservations, the orthodox 

 continental theory of several glacial phases, separated 

 by milder periods, and he attempts to give meteorological 

 precision to geological data. He says that the Chellean 

 period " probably " occurred during the second (Mindel- 

 Riss) interglacial period (p. 31), and he is careful at the 

 same time to add in a footnote a warning that this is a 

 subject of recent controversy (it is indeed ! and not 

 only in recent times). He regards the Mousterian period 

 as falling in the next (Riss-Wurm) interglacial period 

 (p. 63). He quotes evidence for a rainy period between 

 1800 B.C. and A.D. 500, reaching its maximum about 

 400 B.C. The evidence is of many kinds — historical, 

 archaeological, and botanical, the latter being the growth- 

 rings of the giant Sequoias of America, some of which 

 are 4,000 years old ! 



For the book as a whole we have nothing but praise. 

 It is a successful attempt to present in a readable form 

 both facts and opinions. It is also a definite contribu- 

 tion to the subject, for Mr. Brooks is a specialist who 

 can also co-ordinate evidence ; and he is therefore able 

 to give his own dates to the cycles of changing climate. 

 We miss the maps and some of the letterpress which 

 appeared in his original article in the Quarterly Journal 

 of the Royal Meteorological Society (vol. xlvii, 192 1, p. 173) ; 

 but no doubt conditions of space made it necessary to 

 exclude them. It will interest geologists, for there is 

 much geological — or rather pateogeographical — evidence 

 reviewed. This is necessary because Mr. Brooks believes 

 the [last] Ice Age to have been caused by " elevation 

 in h'gh latitudes, and by changes in the land and sea 

 distribution " (p. 23). If the distribution of land and 

 sea can be restored, the temperature can be ascertained. 

 Mr. Brooks shows how, and claims with justice to have 



added precision thereby to the geographical theory of 

 the Ice Age. (Clearly he would welcome that Atlas 

 of Pateogeography for which we have pleaded, perhaps 

 prematurely, but so far in vain.) It will interest meteor- 

 ologists for obvious reasons. Indeed, the peculiar value 

 of ]\Ir. Brooks's work is that he attacks old problems 

 from a new quarter ; and the history of science shows 

 that that is how they have generally been solved. At 

 the same time his knowledge of geological literature is 

 immense. Archaeologists will be interested because the 

 varying influence of climate is of fundamental importance 

 in the evolution of man. Finally, there is nothing in 

 the book that the educated " outsider " cannot under- 

 stand, provided only that he has some notions of geo- 

 logical time. 



But the book must be read critically. The author 

 sometimes states as facts what are really only someone 

 else's theories. That is partly, no doubt, due to a 

 necessarily condensed style, and it is partly the fault of 

 theorists, who do not draw a clear dividing-line between 

 their theories and their statements of generally accepted 

 facts. For instance, on p. 125 he assumes a cultural 

 break between the Maglemose and shell-mound cultures 

 of Denmark, both Early Neolithic ; but there is no evi- 

 dence for this, and Danish archjeologists believe that 

 the one evolved from the other. The facts are quite 

 irrelevant to Mr. Brooks's main thesis, and had better 

 have been omitted, but they illustrate the dangers that 

 beset the path of him who travels widely over the field of 

 knowledge. The obvious safeguaid is, of cour.se, not to 

 stay at home, but to carry a revolver. The highway- 

 men of science must be made in this drastic way to 

 produce their evidence or pay the penalty. In archaeo- 

 logical circles, as in war, it is a safe rule to shoot first 

 and to take no one's word for anything. It is unfortunate 

 that this should be so, but facts are stubborn and are 

 ignored at risk. 



We are very sceptical about Mr. Brooks's attribution 

 of the Chellean to the Mindel-Riss. As regards the 

 Mousterian, recent discoveries in Switzerland seem to 

 prove that M. Boule's correlation is correct and that 

 of Penk incorrect. (A summary of the latest evi- 

 dence is given in the current number of the Wiener 

 Prdhistorische Zeitschrift.) Pumpelly's absolute chron- 

 ology for Anau has been severely criticised and he 

 greatly antedates his cultures. Minor grammatical errors 

 occur on pp. 26 (line 2) and 145 (line 4), and a misprint 

 on tlie second line from the bottom of p. 73. The 

 arrangement and bibliographies are excellent, and we 

 hope the book will be widely read both by specialists 

 and the general public. 



O. G. S. C. 



Remembering and Forgetting. By T. H. Pear, M.A., 

 B.Sc. (Methuen & Co., 7s. bd.) 



The earlier psychologists, in their investigation of 

 memory, endeavoured to treat it as an isolated faculty of 

 the mind, deliberately excluding all meaning from the 



