The following notice was prefixed by the Author to the 

 second edition, published in 1815. 



The infirm state of the Author's health having prevented 

 him, since the publication of the former edition of his 

 Essay on Dew, from making experiments in the open air 

 during the night, and his reading having in the meanwhile 

 been directed to other objects, the present edition of that 

 Essay will be found to contain almost nothing more than 



. the other. The chief difference between the two arises 

 from a change in the form of several of his expressions. 

 He has, for instance, altered the expression of ' saturation 

 with moisture' to that of ' repletion with moisture', in 

 order to avoid the appearance of maintaining, that com- 

 mon air is capable of dissolving water; a tenet uncon- 

 nected with his theory. Sometimes he has subjoined to 

 the phrase, which he now employs, on that subject, the 

 words ' in a pellucid state ;' when this addition has not 

 been made, he wishes it to be understood. 



