14 



PROCEEDINGS OF THE AMERICAN ACADEMY 



II. 



THUNDER-STORMS IN NEW ENGLAND IN THE 

 SUMMER OF 1885. 



By William Morris Davis. 



Presented June 16, 1886. 



Page 



Collection of Material 14 



Reduction of Observations 16 



Daily Maximum Temperatures .... 16 

 General Account of Storms through the 



Summer 17-38 



Thunder-storms of July 9th and 21st . 38-54 



Page 



Review 64-58 



Distribution of Storms through the Day . 55 

 Control of Thunder-storms by the larger 



Cyclonic Circulation 56 



Direction of Motion of Thunder-storms . 57 



The observation of thunder-storms was taken as a special subject 

 of investigation by tlie New England Meteorological Society during 

 the summer of 1885. The considerable expense of the work was les- 

 sened by effective assistance from the Chief Signal Officer, U. S. Army, 

 and the remainder was borne by a grant from the Bache fund of the 

 National Academy. By taking advantage of all available opportuni- 

 tieis, offers of aid were received from about five hundred volunteers in 

 various parts of New England, and about three hundi'ed of these main- 

 tained their interest in the work through the summer, and sent in their 

 records with considerable regularity. The Society is greatly indebted 

 to these observers for their persevering assistance. As success in the 

 work depended entirely on the enlistment of a well-distributed body of 

 observers, effort was made to secure an equal representation of different 

 districts, but not with as much success as it is to be hoped will attend 

 a second season's campaign. Several districts, such as northeastern 

 Connecticut and southeastern Massachusetts, were almost without ob- 

 servers ; while only central and eastern Massachusetts were pretty well 

 covered with stations. The results here stated are therefore in many 

 ways to be regarded as preliminary to those that a more complete in- 

 vestigation may yield in the current year. 



The correspondence with volunteer observers during the summer 

 months, the care of the records as received, and the preliminary tabu- 

 lation and charting of the observations, have been in the hands of Mr. 

 0. N. Oswell, of the U. S. Signal Service, whose careful work has 



