134 Count Rumford’s Enquiry concerning the Nature of Heat, 
powerfully the calorific rays from the sun, which fall on its po- 
lished surface, but also, by its evaporation, generates cold. 
When the sun is gone down, the sweat disappears ; the oil at 
the surface of the skin retires inwards ; and the skin is left in a 
state very favourable to the admission of those feeble frigorific 
rays which arrive from the neighbouring objects. 
But I shall refrain from pursuing these speculations any farther 
at present. 
I shall now proceed to give an account of several experiments, 
of various kinds, which were made with a view to a farther in- 
vestigation of the radiations of cold bodies. 
Having found, by several of the foregoing experiments, that 
the radiations of cold bodies affected my thermoscope very sen- 
sibly, even when placed at a considerable distance from it, and 
in situations where currents of cold air could not be suspected 
to exist, I was desirous of finding out, whether the cooling of a 
hot body would or would not be sensibly accelerated by those 
rays. To determine that point, I made the following expe- 
riment. 
Exper. No. 29. Having provided two conical vessels, made 
of thin sheet brass, each 4 inches in diameter at the base, and 
4 inches high, ending above in a cylindrical neck, 0.88 of an 
inch in diameter, I enclosed each of them in a cylinder of thin 
pasteboard, covered with gilt paper, and then covered them up 
with rabbit-skins, which had the hair on them, in such a manner 
that no part of these vessels, except their flat bottoms, was exposed 
naked to the air. I then covered their bottoms with gold-beater’s 
skin, painted black with Indian ink, in order to render them as 
sensible as possible to calorific and frigorific rays. 
