116 



UNITED STATES. 



I 



shafts to be frequently opened ; but the person who 

 now rents them, experiences no difficulty on that 

 head, and ever since he engaged in them, has had 

 no occasion to open a new place for ore. It is 

 highly probable, our climate is undergoing a change 

 with regard to the quantity of rain. 



Of the evaporation and dryness of the air* 

 On the other hand, observations equally accurate - 

 and numerous testify, that the evaporation of these 

 rains proceeds much more quickly in the United 

 States than in Europe, and that consequently the air 

 there is habitually drier and less calm. Franklin 

 had already made and published this observation, so 

 contrary to the assertions of Pauw, mentioning the 

 circumstance of a mahogany box with drawers, 

 executed with the greatest care by the celebrated 

 Nairn e. The drawers of this box, which fitted ex- 1 

 actly, and even tight at London, were found to be 

 too loose at Philadelphia ; and when it was sent back 

 to London, they became as close and tight as before* . 

 Hence Franklin justly inferred, that the air at Phi- 

 ladelphia was drier than at London : but the case of 

 these two cities was not sufficient to found a general 

 rule. Mr. J. Williams has farther illustrated and 

 established it by some striking facts. 



Tlius, generally speaking, more rain falls in the 

 L^nited States in fewer days than in Europe ; and 

 there are fewer cloudy days, more fair days, and 

 more evaporation. Now the cause of these differ- 

 ent facts appears perfectly simple and unequivocal: 

 it exists in the peculiar state of the atmosphere in 



