CLIMATE, he. 



n 



tiut as the cold does not really finish before April, 

 fo-osts never fail to come on with north-east and north* 

 tvest winds, reproducing the alterations I have al^ 

 ready mentioned. 



Similar variations take place in Summer, and 

 piercing cold succeeds almost every night the violent 

 heats of the day. It is even observed, that the higher 

 the mercury rises in the afternoon, the more it falls 

 in the m.orning at day-break, for these are the two 

 extremes of heat and cold. After a day in which 

 the mercury has stood at 86 and even 90 degrees, it 

 sometimes falls, in the course of a single night, to 

 j55 or even 60 degrees. The mercury from 80 gene- 

 rally falls to 68 degrees ; while it descends when at 

 60 only to 56 degrees. These falls of the quicksil- 

 ver occur particularly after storms of rain and thun- 

 der ; in the Summer of 1775, on such an occasion, 

 it fell 20 degrees, in the space of an hoar and a half. 

 In general, t4iere are few evenings on which a fire 

 would not be agreeable, except during the months of 

 July and August. These variations are not so strik- 

 ing in upper Pennsylvania, toward the sources of the 

 Susquehannah, and on the plains of the Alleghanies; 

 there the cold, in Winter, is more settled, the heat, 

 m Summer, is less intense, and, no doubt, the qua- 

 lity of the air renders it more supportable than in our 

 lower country, where the atmosphere is moist and 

 dense. 



What Dr. Rush here says of Pennsylvania, which 

 is equally applicable to the southern part of New- 

 York, to New Jersey, and to Maryland, is app'icable 

 with very little differenGe, to the coast of Virginia^ 

 and the Carolinas. 



