MEMOIR XIII.] EXPERIMENTS MADE IN VIRGINIA. 205 



Now can we explain these singular results, excepting 

 the last, on any other known principle than this : that 

 the side of the jar nearest the sun radiates freely the 

 heat it receives back again, while radiation is interfered 

 with at the other side ? that, in point of fact, the anterior 

 side is the colder, and the other side the hotter? 



