254 AGRICULTURAL INDICATORS. 



relatively small number of these to be verified is due chiefly to changes of 

 intensity or of pathway in the cyclonic area. In addition, there are more 

 obscure local differences in evidence in almost every storm by which the 

 amount of rain may vary greatly at two neighboring points. As KuUmer and 

 Huntington have pointed out (1914), the shifting of the storm-belt seems to 

 afford a causal explanation of cUmatic differences at the sun-spot maximum 



' and minimum, as well as of variations from one locality or region to another. 

 Thus, while drought periods are general for the West at the double sun-spot 

 cycle, as in 1870-72, 1893-95, and 191&-18, not all regions showed 3 years of 

 drought, and during any one year a few regions recorded a rainfall approach- 

 ing normal. Naturally, the drought was most intense and prolonged in the 

 areas of normally scanty rainfall, and it decreased more or less regularly in the 

 direction of regions of medium precipitation. During such periods, it is even 

 possible that high mountain regions may receive an excessive amount of 

 rain. This seems to result from the principle of compensation, in accordance 

 with which deficit and excess are regularly linked together in time or in space. 

 For the present, this is regarded as the most plausible explanation of variations 

 and inconsistencies in the behavior of the climatic cycle, but it is probable 

 that further knowledge will show that these are connected with the differentia- 

 tion of contiguous climates. Hence, while the method of cycles can not as- 

 sume to forecast the number of inches of rain for any locality during a certain 

 year, it can predict the recurrence of drought periods and of succeeding wetter 

 years for the West in general. The drought period will concern three regions 

 out of four during most of its duration, and it will affect practically every 



' locality at some time during its phase. 



Utilization of cycles. A study of settlement in the West since 1865 reveals 

 the fact that it corresponds more or less closely to the climatic cycle. The 

 exceptions are afforded by the rapid inrush after the homestead act, the Kin- 

 kaid act, etc., or after the opening of new regions. The general movement of 

 settlers has advanced and receded in almost perfect agreement with the wet 

 pha-ses and drought periods of the climatic cycle (cf. Bruckner, Huntington 

 1914: 89). A few years of unusual rainfall have afforded unscrupulous real- 

 estate dealers and immigration commissioners an opportunity to dispose of 

 even the most worthless land. The ensuing drought period then led to crop 

 failure and the wholesale abandonment of the region, to be followed by 

 another influx of settlers during the next wet phase. In more than one region 

 of the West this process has been repeated three or four times, and its dis- 

 , astrous operation will continue until the States and the National Government 

 , recognize the necessity of prop)er land classification and of adequate regulation 

 of settlement. 



The knowledge that drought periods will recur is indispensable to any 

 accurate and successful classification of land and to the economic manage- 

 ment of dry-farm, grazing range, or forest. These results, which are of the 

 first importance for the West, do not depend necessarily upon the accuracy of 

 predictions based upon the sun-spot cycle. They are clearly indicated by the 

 actual experience of the last 60 years, which not only confirms the recurrence 

 of drought periods, but also suggests the interval. However, it is clear that 

 it would be of the greatest value to be able to forecast the date, duration, and 

 intensity of each drought period with some accuracy, as well as to anticipate 



