THE 
‘QUARTERLY JOURNAL, 
April, 1824. 
Art. I. On some Phenomena relating to the Formation 
of Dew on Metallic Surfaces. By George Harvey, 
M. G..S.,.5:¢;. de. 
[Communicated by the Author.] 
It is a curious fact, mentioned by Dr. Wells, in his valuable 
Essay on Dew, that if a metallic substance be closely attached to 
‘a body of some thickness, which attracts dew powerfully, the ten- 
‘dency of the metal to promote the formation of moisture on its sur- 
face, instead of being increased from the circumstance, is dimi- 
nished, provided the metal covers the whole of the upper surface 
‘of the body to which it is attached*. This principle he illustrated 
by the following experiment: Two pieces of very light wood, each 
four inches long, a third of an inch wide, and one tenth of an inch 
thick, were joined in the form of a cross ; and to one of its sides 
the non-metallic surface of a square piece of gilt paper was at= 
tached, by means of mucilage. On exposing the metallic surface 
‘on a dewy night, by suspending it ina horizontal position, about six 
inches above the ground, he found after a few hours, that the parts 
of the metallic paper, not in contact with the wood, had minute 
drops of dew on their surfaces, while those in contact with the 
‘cross, were perfectly dry. 
In repeating this experiment, I have employed gold and silver 
* Wells on Dew, page 22, second edition, 
Vou. XVII. B 
