9 2 Count Rumford’s Enquiry concerning the Nature of Heat , 
When we consider this experiment with attention, we shall 
find reason to conclude, that if it were by facilitating the ap- 
proach and temporary contact of a succession of fresh particles 
of the cold air of the room to the surface of the glue, (which was 
now in fact become the surface of the hot body,) that the 
cooling of the instrument was accelerated, the metal being as 
completely covered, and the air, supposed to be attached and fixed 
to its surface, as completely excluded by one coating of the glue 
as it could be by two, or more, two coatings could not possibly 
accelerate the cooling of the instrument more than one ; but if, 
on the other hand, the cooling of the instrument in this experi- 
ment was accelerated, not by facilitating and accelerating the 
motions of the circumambient cold air, but by facilitating and 
increasing those radiations which are known to proceed from hot 
bodies, I conceived that two coatings of the glue might possibly 
accelerate the, cooling of the vessel more than one. In order to 
put this conjecture to the test, I made the following decisive 
experiment. 
Exper. No. 3. I now gave the instrument No. 2 a second 
coating of glue ; and, when it was thoroughly dry, I repeated 
the experiment last mentioned, with thelabove variation ; when I 
found the results to be as follows. 
Time of cooling 
the 10 degrees 
in question. 
The instrument No. 1, naked metal - - 55^ min. 
No. 2, covered with two coatings of glue 37^ min. 
Finding that two transparent coatings of glue facilitated 
the cooling of this instrument even more than one coating, I 
washed off all the glue with warm water ; then, making the in- 
strument as clean and bright as possible, I covered its sides with 
