232 



J. P. Hall — Short Cycle in Weather. 



Series III : 



1886. 





Date. 



Interval 



Date. 



Interval. 



D: 



Jan, 12, 



XXXJt 



Jan. 4, 



**** 





Feb. 5, 



24 



Jan. 28, 



24 





March 1, 



24 



Feb. 25, 



28 





Mar. 27-9, 



27 



March 25-6, 



28 



E: 



Jan. 24, 



**** 



Jan. 17-21, 



■?:--:.-*-;:- 





Feb. 20, 



27 



Feb. 13-19, 



28 





March 20, 



28 



March .. 



.. 





April 16, 



27 



April 10-13, 



55 









15 



That these and kindred oscillations in New York City are, 

 in the main, representative of temperature-changes over the 

 greater part of the United States becomes evident when one 

 compares the curves for that place with those for St. Paul and 

 St. Louis. Indeed, one may go beyond the Rocky Mountains 

 for this purpose, although at first sight the result is a little un- 

 satisfactoiw. The four traces presented in Series IV (covering 

 August, 1891), are offered rather to illustrate than to demon- 

 strate the close general parallel 

 between temperature-curves 

 for stations in almost the same 

 latitude, in a chain reaching 

 nearly or quite across the con- 

 tinent. Were the testimony 

 of five years instead of a single 

 month offered the resemblance 

 would still hold good. In- 

 deed, probably no meteorolo- 

 gist would question it. It 

 should be observed, however, 

 that in point of time, there is 

 a sensible difference between 

 places widely separated in 

 longitude, in which respect 

 these curves are unlike traces 

 of magnetic storms, which ex- 

 hibit deflections all around the 

 globe at practically the same 

 instant of time. But a con- 

 spicuous rise in temperature 

 at New York is apt to be a 

 day or two behind that at St. 

 Louis, fully two days behind St. Paul, and sometimes nearly a 

 week behind Utah. The eastward progress of warm and cold 

 waves across the continent is one of the most familiar phenom- 

 ena in meteorology. There is, in Series IV, for instance, a 

 rise (A) at Salt Lake City, culminating there on Aug. 4, at St. 

 Paul on the 8th, St. Louis the 10th, and New York the 10th 



