On the Power of Fluids to conduct Heat. 978 
those degrees, the expansion has an increasing 
ratio, and at 32° it amounts to 4th of an inch, 
or about zisth part of the whole expansion’ from 
42° to 212° or boiling heat.—During the in- 
vestigation of this subject, my attention was ar= 
rested by the circumstance, that the expansion of 
water was the same for any number of degrees 
from the point of greatest condensation, no mat- 
ter whether above or below it: thus, I found 
that 32, which are 1004 below the point of 
greatest density, agreed exactly with 530, which 
are 10° above the said point; and so did all the 
intermediate degrees on both sides, Conse- 
quently when the water thermometer stood af 
53°, it was impossible to say, without a know- 
ledge of other circumstances, whether its tem- 
perature was really 53°, or 32°. Recollecting some 
experiments of Dr, Blagden in the Philosophical 
Transactions, from which it appears that water was 
cooled down to 21° or 22° without freezing, I 
was Curious to see how far this law of expansion 
would continue below the freezing point, pre- 
viously to the congelation of the water, and 
therefore ventured to put the water thermometer 
into a mixture of snow and salt, about 25° below 
the freezing point, expecting the bulb to be burst 
when the sudden congelation took place. After 
taking it out of a mixture of snow and water, 
where it stood at 32° (that is 53° per scale) I 
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