Dr. Blagden’s Report 
3 There would be two methods of computing the fpecific gra- 
vity at the different temperatures, from thefe numbers; one, 
by taking the weight of the water, at the particular tempera- 
ture in queftion, for the ftandard; and the other by fixing on 
one certain temperature of the water, for mftance 6o°, to et e 
ftandard, with its bulffat which that of the fpmt at all dif- 
ferent degrees fhall be compared. I have preferred the latter 
method, though not the moll ufual, becaufe it (hews, more 
readily and fimply, the progreffion obferved in the changes of 
fpecific gravity, according to the heat and ftrengt 1 o vt 
mixture. This method, however, rendered it neceffary o 
make an allowance for the contraaion and expanfion of the 
bottle ufed for weighing the liquors, according to t ie ev iat J° n 
of their temperature from 6o°, either below, or a ove. o 
obtain this corredion, the expanfion of hollow gla s was ta en 
from General Roy’s experiments in the LXXVth volume o 
the Philofophical Tranfadions, as ,00005x7 of an inch upon 
a foot for every degree of heat, whence its effed, m enlarging 
the capacity of a fphere, was computed, and the refu .ting cor- 
redion added to the weight of the liquors in heats below 60 , 
and fubtraded from it in heats above. On the fame accoun a 
third column is given, in the preceding table, to rew t e pe 
cific gravity of water at the different temperatures, its weight 
at 6o° being taken as the ftandard. , 
Another corredion alfo became neceffary, on account o 
part of the ftem of the .thermometer which was not immeried 
in the liquor. This inftrument, made by Ramsden, had its 
ball ,22 of an inch in diameter, and its ftem 13 inc es in 
length. From the ball to the commencement of the fcale 13. 
inches of the ftem were bare, and then the fcale began, w^cn 
