NO. 3 



SOLAR VARIATION AND WEATHER — ABBOT 



51 





ti:kMibB 



A^^ 



mSmii 



m^^W: 



mx^i^p- 



Fig. 42. — Periods in human pulse rate, harmonics of 273 months. 



tury. The data are arranged in cycles of 46 years. It will be mani- 

 fest that each 46-year cycle shows near its beginning a great depres- 

 sion of about 10 years length from crest to trough, and a smaller 

 depression of about the same length following 23 years later. The 

 great depressions following years 1838, 1885, and 1929 were each 

 associated with disastrous droughts in the Northwestern States and 

 adjacent regions of Canada. There is much reason to expect a 

 recurrence of such a drought beginning about 1975." 



The two principal periods of 91 and 45-1/2 years, 4 and 2 times 

 273 months, depress Lake Huron about 5 feet. They last before 

 complete restoration of level about 10 years. A drought of less 

 magnitude in the supply area of Lake Huron has the single 273- 

 month period. I predicted about 1938 its recurrence in the decade 

 of 1950-1960. It proved very severe in Southwest United States 

 and is plainly forecasted by my study of St. Louis precipitation "60- 

 year Forecast" with a forecast of its end in 1957. (See P. 4211, 



