June 11, 1915] 



SCIENCE 



865 



intellectual laity and within the narrower 

 circle of more critical students. A more fasci- 

 nating volume to those who endeavor to 

 glimpse the ancients as living beings overcom- 

 ing and being overcoming by their environ- 

 ments, than "Palestine and Its Transforma- 

 tion " has rarely been written, and in it 

 Professor Huntington in a measure has antici- 

 pated the feature of the present volume which 

 to the biologist especially will make the most 

 intimate appeal. As the author remarks in his 

 preface, his thesis of climatic pulsations within 

 measurably recent times may till now have 

 been open to the criticism that the facts may 

 have been arranged to fit the theory, but grant- 

 ing this to be so, we have now given us indu- 

 bitable evidence, mathematically treated, de- 

 rived from growth rates of the " big trees," so 

 that in the absence of instrumentation we are 

 supplied with a rainfall curve dating back over 

 3,000 years, which, viewed broadly, is little less 

 dependable for that lack. 



The method of attaining this end is credited 

 to Professor A. E. Douglass, who, while resi- 

 dent in Flagstaff, conceived the idea of show- 

 ing association between meteorological varia- 

 tions and astronomical phenomena during long 

 periods of time for which records are not avail- 

 able. This method is presented by him in 

 Chapter XI. of the volume. The fundamental 

 data are the measurements of the growth rings 

 in old trees obtained in numbers sufficient to 

 allow the determination of the amount of 

 error dug to various causes and their elimina- 

 tion. The errors considered by Douglass are 

 those introduced by the irregularities of growth 

 due to discontinuity of moisture supply during 

 the growing season, such errors being of rela- 

 tively greater importance in comparing growth 

 and recorded rainfall, during a comparatively 

 short period of years. The results of the in- 

 vestigation are correct within a range of 70 

 to 82 per cent., and certainly sufficiently so to 

 warrant reliance upon tree growth as an indi- 

 cator of climatic variations. Growth rates 

 for a period of 600 years were then studied, a 

 correction for age being indicated, and from 

 the result it is clearly to be inferred that cli- 

 matic pulsations have occurred during the pe- 

 riod in question. These, it is finally argued. 



are expressions of weather changes due to sun- 

 spot activity, a view supported by data from 

 German trees. 



In the following chapters Huntington ap- 

 plies the above method, introducing an addi- 

 tional correction for " longevity," the effect of 

 which is to still further rectify the curve em- 

 bodying a correction for age, and to make the 

 sinuosities of the growth curve comparable at 

 all points throughout its extent. The evidence 

 for pulsations of growth is further found in 

 trees widely scattered from Maine to Cali- 

 fornia. It is, however, to be noted that in- 

 verse growth fluctuations occur, as for example 

 when a change which produces a " drought in 

 the north may produce an excess of moisture in 

 the south." This extension of method then 

 leads the way to a dramatic climax in the fol- 

 lowing two chapters in which the special diffi- 

 culties presented by the "big trees" of Cali- 

 fornia are dealt with and the interpretation of 

 their growth curves is presented. The original 

 data are recorded in the statistical portion of 

 the volume, where 28 pages are found crowded 

 with tabulated figures at which one must look 

 in order to form some conception of the 

 enormous amount of work of a purely induc- 

 tive kind upon which the author's conclusions 

 rest. The derived curve of tree growth for 

 3,000 years and the curve for climatic change 

 in western Asia based upon historical data, on 

 page 172, must remain, whatever the minor in- 

 accuracies may turn out to be, of preponder- 

 ating interest for students of climate, and wiU 

 become an item of classical value. 



From these curves there emerges the con- 

 clusion that beyond the cycles of lesser ampli- 

 tude embraced within shorter time periods 

 (120, 21 and 11 years) others occur " of the 

 length of centuries " but without recognizable 

 periodicity, and that these pulsations, to use 

 the author's favorite term, have been synchron- 

 ous in western America and western and cen- 

 tral Asia. His methods, tested against each 

 other in this volume, point also to a condition 

 300 years ago on the whole moister than now 

 obtains. 



Inquiry into the possible causes of the dis- 

 coverable fluctuations occupies Chapter XIX., 

 in which a variety of evidence, including solar 



