Cold in Animal Bodies. 
3 
haps the weather, when hazy and loaded with 
vapour, Teems to our feeling, hotter than when 
pure and rare although by the thermometer it 
is found to be equally warm in both inftances. 
This alfo was the true reafon why, in making 
thofe experiments, Dr. Fordyce always found that 
he could bear a greater degree of heat in dry, 
than in modi air. But nothing Thews more 
clearly the flownefs with which heat is imparted 
to a denfer fubftance, from one that is highly 
rarefied, than a circumftance mentioned in the 
paper in queftion : “ that even the fmall quan¬ 
tity of mercury, contained in a thermometer 
which the gentlemen carried with them into the 
room, did not arrive at the degree to which the 
air was heated, during the whole time they re¬ 
mained there.” 
II. Another caufe which, in the given fituation, 
would diminifh the effed of the heated air, is, 
’The evaporation made from the fur face of the body. 
That evaporation produces a confiderable ab- 
forption of heat is well known : and, in making 
the experiments, there is reafon to believe, that it 
took place in a confiderable degree. Dr. Fordyce, 
anxious perhaps to eftablifh his general law, 
feems unwilling to allow its influence. But when 
it is confidered, that by the operation of the heat, 
the force of the circulation was increafed, the 
pores of the (kin relaxed, and the prtflure of the 
internal air diminifhed j when we are told, that 
B 2 a turgef- 
