340 



PROCEEDINGS OF THE AMERICAN ACADEMY 



July 9. 



Methods of Observation elsewhere. — We may now consider the 

 demands made upon observers by various services where the syste- 

 matic study of thunder-storms has been undertaken : at the same time, 

 a few notes are added on the general standing of the work in several 

 countries.* 



France. System founded by Leverrier in 1865; reductions in 

 charge of Fron, and now published in the Annales du Bai-eau central 

 meteorolugique. As an incentive to observation, a large number of 

 maps illustrating the paths of certain storms were distributed to the 

 observers during the first season's work. I do not know how far this 

 practice has been continued. There have been over one thousand 

 observers in recent years. 



Observations : time of first, loudest, and last thunder ; direction of 

 storm's appearance and disappearance ; velocity and direction of clouds ; 

 force and direction of wind ; intensity of lightning, thunder, rain, hail ; 

 direction of distant lightning ; general notes on the appearance of the 

 storm, and on its injurious effects. 



Intensity is expressed on a scale of six ; direction is observed to 

 octants. The records are made on a quarto page, and are sent free, 

 folded but not sealed, through the mail, to the departmental prefects, 

 by whom they are discussed before finally going to Paris. 



* I am indebted to Mr. A. Lawrence Kotch for opportunity of examining his 

 collection of " forms " for observation, from wliicli many of tliese notes are 

 taken. 



