of Dew on Metallic Surfaces. ; 3 
During the prosecution of these experiments, J have had fre- 
quent opportunities of remarking that silver metallic paper per- 
mits dew to be deposited earlier, and in greater abundance on its 
surface, than gold. arly in the month of April, at nine p. m., 
a large pane of glass was placed on the green herbage, and on it 
the squares of gold and silver paper attached to their respective 
crosses. The clear and transparent sky, joined to the perfectly 
tranquil state of the atmosphere, indicated the possibility of a co- 
pious deposition of dew. At six the next morning the grass exhi- 
bited the appearance of a thick hoar frost, and the moisture which 
had been formed on the upper and under sides of the glass during 
the night, presented coats of transparent ice. On referring to the 
squares of metallic paper, that of gold was found removed from the 
glass on which it had been placed the preceding evening, to the 
distance of six feet; its change of situation having been probably 
produced by the force of some breeze during the night. ‘The me- 
tallic side was in contact with the grass, and on taking it up it 
presented four beautiful triangles, completely covered with innu- 
merable particles of frozen dew. Those parts of the metal which 
had their inferior surfaces in contact with the wood, exhibited the 
perfect and well defined form of the cross, represented in fig. 6, The 
appearance of the crystalline triangles, when contrasted with the 
golden surface ef the cross, was extremely beautiful ; and it was 
remarked, that as the gradually increased warmth of the morning 
dissolved the crystals of dew, the moisture was still confined to the 
same triangular surfaces: thus preserving completely the form of 
the cross. Minute crystalline atoms were also perceptible on the 
non-metallic side of the paper, and which, likewise dissolving, had 
a sensible effect on the rigidity of the paper. On examining the 
silver square which had preserved its situation on the glass, its 
metallic surface was found without the appearance of moisture, 
under any form, on its surface. 
A hasty consideration of this phenomenon might lead us to infer, 
that dew is more readily deposited on gold than on silver, con~ 
trary to what has been before remarked, as the result of extended 
