Dr. Blagden’s Report 
eoual to what would indicate, in the above-mentioned mixture, 
about one-feventh of a grain of water more than the truth, to 
100 of fpirit : a quantity much too minute for the confideration 
of Government. 
part II. 
* 
On Hydrometers. 
THE readied way of afcertaining fpecific gravities, and un- 
doubtedly the mod convenient for public bufinefs, is by hy- 
drometers ; and, I conceive, thofe of the fimpled conduc- 
tion to be bed upon the whole, efpecially if more accurate 
means are kept at hand, to be reforted to in cafe of difputes. 
An hydrometer of glafs would be the mod certain ; but whether 
it be of that fubdance, or of metal, it diould confid of a ball, 
or rather bulb, fo poifed as that a certain part diould be always 
downmod in the liquor, and having a dem rifing from it on 
the oppodte part, which would confequently keep upright in 
ufing the indrument. On the fize of this dem, the fenlibility 
of the hydrometer chiefly depends. In the old areometers the 
dem was made fo large, that the volume of water difplaced 
between its lead and greated immerfions was equal to the 
whole difference of fpecific gravity between water and alcohol, 
or perhaps more ; whence its dale of divifions mud be veiy 
fmall, and could not give the fpecific gravity with much accu- 
racy. To remedy this defed, weights were introduced, by 
means of which the dem could be made fmaller, each weight 
affording a new commencement of its fcale ; fo that the fize of 
the divifions on a given length of dem was doubled, tripled, 
\ - quadrupled^ 
