250 THE CHEMISTRY OF CREATION. 



regards " dry fog," principally in the enormous 

 extent of its distribution a circumstance of 

 which history is unable to. offer a parallel 

 example. Dry fogs of a local, or more limited 

 extent, had been before known. Jussieu 

 relates, that " the influenza of the spring of 

 1733 appeared in France immediately after 

 offensive fogs, more dense than the darkness 

 of Egypt!" In the autumn of 1775, in France 

 influenza appeared with violence, and was 

 ushered in by thick noisome fogs, having been 

 preceded by diseases among the lower animals. 

 About the 7th of October, 1775, Scotland 

 appears to have been visited by the same fog, 

 for we learn that in certain districts a continual 

 dark fog, possessing a particularly smoky smell, 

 made its appearance, and lasted for five weeks. 

 During its continuance the sun could not be 

 seen to shine. During the year that the potato 

 disease was most extensive in its ravages, it 

 was noticed in some parts of the country, that 

 clouds of " dry fog " preceded its appearance in 

 some fields. 



It has been remarked by some, who have 

 sought for the causes of these singular occur- 

 rences, that they often occur together with 

 volcanic disturbances. In 1782, besides the 

 tremendous eruption already mentioned, there 

 occurred several earthquakes in Calabria, and 



