June 11, 1915] 



SCIENCE 



867 



gated, since the work, whicli would have been 

 done by the women, would have amounted in 

 the case of the Great Trinchera to enough to 

 demand a population of 15,000, "where now 

 there are scarcely more than 200," in view of 

 which it seems far more likely that dry farm- 

 ing was possible, and this in turn supposes a 

 greater rainfall than occurs at present. 



But the main effort is to show that not only 

 has there been a change in rainfall during the 

 last few hundred years, but that the whole re- 

 gion studied presents evidences of successive 

 stages of culture. The evidence derived from 

 human agencies is of course the more diificult 

 to obtain and interpret, but taken together 

 with that from other sources, it gives more 

 than suggestive strength to the discussion. 

 For example, the early Spaniards found no in- 

 habitants in the Chaco Canyon, while their 

 artefacts show them to have been different from 

 the more modern Pajaritans. The extremely dry 

 character of the region indicates that it would 

 have become uninhabitable earlier than other 

 localities which have been occupied at later 

 dates. 



In this connection southern Mexico is 

 treated as a test ease and similar conclusions 

 are arrived at, while three other chapters deal 

 with Yucatan, with Guatemala and the High- 

 est Native American Civilization, and with 

 the Relation of Climatic Changes to Mayan 

 History. The rich indications, buried now in 

 well-nigh impenetrable jungle, of a highly 

 able and intelligent people, are found in a 

 region which forbids at the present any ap- 

 proach to civilization at all, in view of the 

 great heat, disease and the consequent debil- 

 itating effects. But a small decrease in rain- 

 fall would alter these conditions, so that what 

 would cause the disappearance of people in 

 temperate regions would permit their greater 

 development in the tropics, since a diminu- 

 tion of rainfall sufficient to allow the develop- 

 ment of dense forests would cause them to be 

 replaced by jungle, and the jungle, in turn, by 

 bush. A healthful atmosphere would thus dis- 

 place a noxious one, and human progress, 

 otherwise inhibited, would be stimulated. But 

 this means that while the deserts of the south- 



west are drier now than formerly, the scenes of 

 former Mayan greatness are now moister, in 

 apparent contradiction to the major thesis of 

 the volume. At this point a paper is contrib- 

 uted by Dr. Charles J. Kellmer on " The 

 Shift of the Storm Track." It is shown that 

 during an interval of 21 years the storm track 

 has shifted a small distance to the west and 

 south, and it is perhaps more than a mere 

 coincidence that the magnetic pole has also 

 shifted (according to Bauer) westward and 

 (chiefly) southward. This broaches the sub- 

 ject of the latitudinal change of climate due 

 to this cause, and if, as Huntington contends, 

 such changes have occurred in the lands of the 

 Mayas, the general contention that the pro- 

 found changes in human culture, indicated by 

 their reliquise, are due to them. In this 

 light, the Mayan history is reviewed in Chapter 

 XVIII., and a parallel is drawn between the 

 climatic changes as registered by tree growth 

 and the rise, decline, renascence and ultimate 

 reduction to a rather low grade of culture, of 

 the Mayan people, not so low, however, as that 

 of other tropical peoples. In this study, his- 

 tory and archeology are brought together, and 

 if the results are, as Huntington says, not too 

 much to be depended on, the treatment again 

 illustrates the method of coordinating evidence 

 from these and other sources in order to get a 

 broader view of the possible causes of culture 

 changes in the past. The surai total of the 

 work is to strongly indicate a general paral- 

 lelism between these changes in central Amer- 

 ica and the desert regions to the north and 

 those of central and southwestern Asia as cor- 

 related with the climatic pulsations indicated 

 in the growth records drawn from a minute's 

 study of the California trees. 



The volume is a big one, and really too big 

 and too detailed, and with evidence drawn from 

 too many kinds of sources for competent re- 

 view by a single reader. If this review fails in 

 the critical attitude, a good purpose will be 

 served if, besides indicating the scope of the 

 studies, the general attention is directed to 

 large and conscientious effort, supported by 

 great if restrained enthusiasm, to work out an 

 intricate problem which has an intimate bear- 



