304 Sir Benjamin Thompson’s Experiments , &c. 
Taking now the conducting power of mercury = 1000, the 
conducting powers of the other mediums, as determined by 
thefe experiments, will be as follows, viz. 
Mercury « , 1000 
Moift air * » 330 
Water, . . 313 
Common air, denfity=i 80-/^. 
Rarefied air, denfity=:| . 8o x y 5 - 
Rarefied air, denfity = .J T 78 
The Torricellian vacuum 55 
And in thefe proportions are the quantities of heat which 
thefe different mediums are capable of tranfmitting in any 
given time ; and confequently thefe numbers exprefs the rela- 
tive fenjible temperatures of the mediums, as well as their con- 
ducing powers. How far thefe decifions will hold good under 
a variation of circumftances experiment only can determine. 
This is certainly a fubjeCt of inveftigation not lefs curious in 
itfelf than it is interefting to mankind ; and I wifh that what I 
have done may induce others to turn their attention to this 
long negleCed field of experimental inquiry. For my own 
part, I am determined not to quit it. 
In the future profecution of thefe inquiries, I do not mean 
to confine myfelf folely to the determining of the conducting 
powers of fluids; on the contrary, folids, arid particularly 
fuch bodies as are made ufe of for cloathing, will be principal 
fubjeCs of my future experiments. I have indeed already 
begun thefe refearches, and have made fome progrefs in them ; 
but I forbear to anticipate a matter which I propofe for the 
fubjeC of a future communication. 
