178 ESSAY 



with publishing his discovery, but his friend 

 Dufay concluded from it, that dew is an electric 

 phenomenon, since it leaves untouched the 

 bodies, which conduct electricity, while it ap- 

 pears upon those, which cannot transmit that 

 influence. If dew, however, were to form on 

 the latter only, its quantity would never be suf- 

 ficiently great, to admit its being distinctly seen -, 

 for the non-conductors, as soon as they became 

 in the least moist, would be changed into con- 

 ductors. Charcoal, too, it is now known, though 

 the best solid conductor of electricity after the 

 metals, attracts dew very powerfully ; and, in 

 the last place, contrary to the assertion of Du- 

 fay, dew frequently forms upon metals them- 

 selves. 



Other authors have ascribed the production 

 of dew to electricity, for reasons different from 

 that of Dufay. But there are several considera- 

 tions, which seem to me to prove, that no such 

 opinion can be just. 1. When dew is produced 

 in a clear atmosphere, the portion of air, by 

 which it is deposited, must necessarily be un- 

 able, at that moment, to retain, in a state of pel- 

 lucid vapour, all the moisture, which it had 

 immediately before held in that form. But I 

 know of no experiment, which shows, that air, 

 by becoming positively electrical, which is said 

 to be its condition on the evenings, during which 



