Origin of Eight-Year Generating Cycle 85 



tance of this great increase in the utihzable meteoro- 

 logical observations is shown in what is, I think, the 

 most pregnant conclusion of Professor Bigelow's Report. 

 I shall quote that conclusion at length and invite par- 

 ticular attention to a few sentences which I have put 

 in italics. The table referred to in the quotation is one 

 in which the final mean pressures for the whole of the 

 United States and for the several constituent large 

 sections are presented. In detail, the barometric pres- 

 sure series upon which the generalization was based 

 were obtained from the following sections: North 

 Atlantic, South Atlantic, Lake Region, Pacific, West 

 Gulf, North Plateau, South Plateau, and from the 

 records of these regions all combined into a general 

 mean. The pregnant quotation is now given: 



" We are at once struck by the remarkable fact, 

 which constitutes an important discovery in baro- 

 metric science, that the secular variations of the ba- 

 rometer from year to year are by no means acci- 

 dental but a phenomenon of definite proportions. 

 In looking over the tables it is seen that for certain 

 years the barometric reading is persistently lower 

 than the average of the series, and for certain other 

 years it remains higher than the average. This fact 

 is indicated, generally, by each station in the group, 

 most conspicuously for the year 1878. The residuals 

 of that year are persistently minus, about -0.050 inch 

 for each station in every group for the entire United 

 States; for the year 1883 they are as persistently 

 plus, about +0.020 inch. This constitutes a range 

 of 0.070 inch, and when we consider that the annual 



