Benjamin Franklin. 239 



the day lengthens, the cold strengthens ; ' the causes of 

 refrigeration continuing to operate, while the sun returns 

 too slowly, and his force continues too weak to counteract 

 them. 



' During several of the summer months of the year 1783, 

 when the effect of the sun's rays to heat the earth in these 

 northern regions should have been greatest, there existed 

 a constant fog over all Europe and great part of North 

 America. This fog was of a permanent nature; it was 

 dry, and the rays of the sun seemed to have little effect 

 towards dissipating it, as they easily do a moist fog, 

 arising from water. They were indeed rendered so faint 

 in passing through it, that when collected in the focus of a 

 burning glass, they would scarce kindle brown paper. Of 

 course, their summer effect in heating the earth was ex- 

 ceedingly diminished. 



* Hence the surface was early frozen. 



* Hence the first snows remained on it unmelted, and 

 received continual additions. 



* Hence the air was more chilled, and the winds more 

 severely cold. 



' Hence perhaps the winter of 1783-4 was more severe 

 than any that had happened for many years. 



' The cause of this universal fog is not yet ascertained. 

 Whether it was adventitious to this earth, and merely a 

 smoke proceeding from the consumption by fire of some 

 of those great burning balls or globes which we happen to 

 meet with in our rapid course round the sun, and which 

 are sometimes seen to kindle and be destroyed in passing 

 our atmosphere, and whose smoke might be attracted and 

 retained by our earth : or whether it was the vast quantity 

 of smoke, long continuing to issue during the summer 



