[ 46 ] 



ficiency of thefe caufcs ; and laftly, I fliall explain that which to 

 me feems more adequate to the effedJ. 



FIRST OBSERVATION. 



The more confiderable elevations and deprefTons of the $ in 

 the barometer happen at a very fhort interval of time in places 

 very remote from each other. This correfpondence was obferved 

 by Mr. Derham in 1699 between the heights of the ? at Upmin- 

 fter in Eflex and Townley in Lancafhire ; and afterwards by 

 Mr. .Maraldi, between the variations at Paris and Genoa*, at the 

 diftance of nearly four degrees of latitude. Mr. Derham alfo 

 obferved nearly the fame agreement between barometers at Berlin, 

 lat. 53°, and Pithasa, lat. 65°!; as did Afclepi between thofe at 

 Rome, lat. 42°, and at Padua, lat. 45° J. But I have remarked 

 that where there is a confiderable difference of longitude, the 

 like agreement is not found. Thus Mr. Hadley found that at 

 London and Padua the variations are frequently in oppofitc 

 diredions § ; and fo they commonly are at Ponoi, lat. 670, 

 long. 47° E. and Peterfhurgh, lat. 60° long 30° E. ; and the dif- 

 cordance is ftill greater between the variations at Peterfbnrgh and 

 thofe at Jakutllii, lat. 62°, long. 129° E. || ; Maraldi obferved alfo 

 that different winds prevailed at Paris and Genoa during the corref- 



* Mem. Par. 1 709. 

 t VIII. Phil. Tranf. Abr. 

 t La Cotte Mctereol. p. 181. 

 - j VIII. Phil. Tranf. Abr. p. 587. 

 II XIV. N. A a. Petrop. 



ponding 



