f at different Degrees of Heat. 2 7 r 
fame piece of iron be weighed in water of the temperature of 
75 0 , it will lofe but 1 3,31 3 grains; for the Ioffes of weight 
will be as the weights of equal volumes of water at thole tem- 
peratures, which, as we have feen, are as 253,18 to 252,8 ; there- 
fore, its fpecific gravity in water of the temperature of 62® 
will be 7,49; and in water of the temperature of 75 0 . 7,511 
hut we may correct this by the above analogy, for 
253,8 . 252,18 :: 7,51 i , 7,49. 
By this means we obtain the advantage of discovering the 
true weight of a cubic foot of any fubftance whole Specific gra- 
vity is known, which it is now plain cannot be known when 
bodies are hydroftatically weighed at any temperature a few 
degrees above or below 62°, without Such redu&ion, or Sub- 
tracting the quantities in the fourth column. 
This method is equally applicable, and with equal nec effity, 
to other means of finding Specific gravities, as areometers, the 
comparifon of the weights of equal meafures of liquids, the 
different Ioffes of weight of the Same Solid, when weighed in 
different liquids, &c. In all which cafes the weight of water 
at 62°, or the lofs of weight of a Solid in water at 62°, (hould. 
be found by the above analogy. 
Dr. Hales and Some others have effimated the weight of a 
cubic inch of water at 254 grains,, which is an evident miftake, 
as it is true in no degree of temperature, and produces an error 
of more than three ounces in the cubic foot. 
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