and the Mode of its Communication. *53 
which covers, and adheres to, the surface of a metal on which the 
drop reposes ; but, at lower temperatures, this does not seem to 
be the case. 
The following experiment, which I made several months ago, 
with a view to investigate the cause of the slow evaporation of 
drops of water placed on hot metals, will, I think, throw much 
light on this subject. 
Exper. No. 34. Taking a clean polished silver spoon, I 
blackened the inside of it, by holding it over the flame of a wax 
candle ; then, putting a large drop of water into it, I found, as I 
expected, that the drop took a spherical form, and rolled about 
in the spoon, without wetting its blackened surface. 
I now held the spoon over the flame of a candle, and attempted 
to make the water boil ; but I found it to be absolutely impos- 
sible. The handle of the spoon became so very hot, that I could 
not hold it in my hand without being burnt, though it was 
wrapped up in three or four thicknesses of linen ; but still the 
drop of water did not appear to be at all affected by this intense 
heat. If the bowl of the spoon were touched with the Anger, a 
hissing noise announced that it was extremely hot ; but still, 
the water remained perfectly quiet in the spoon, without being 
evaporated. 
Having in vain attempted to make this drop of water boil, and 
not being able to hold the spoon over the flame of the candle 
any longer, on account of the heat of its handle, I now poured 
the drop into the palm of my hand. I found it to be warm, but 
by no means scalding hot. 
By holding the spoon, with a pair of tongs, over the flame of 
the candle for a longer time, I found that a drop of water in 
MDCCCIV, X 
