il6 Opinion on Hydrometers, by Dr. Hare- 
has been enjoined upon our revenue officers. But, 
the hydrometer of Dicas. It consists of a bulb, with a slen- 
der stem, which have a certain ratio, in bulk, to each other. 
The stem being, throughout, homologous in form, and of 
equal dimensions, and being graduated longitudinally into 
equal parts. The aggregate is of such a specific gravity, as 
that, when placed in alcohol of the specific gravity of 800, 
nearly the whole of the bulb will be submerged, and all the 
graduated part of the stem; so that the surface of the liquid 
will be at 0. If placed im spirit a little weaker, a portion of — 
the uation of the stem will be above the surface of the 
liquid. The degree which coincides with this surface, being 
hoted, opposite to the same number, on a scale accompany- 
ing the instrument, will be found the strength of the spirit, or 
the per centage of water more or less than would make it 
© proof spirit which is of the gravity of about .9218, 
and consists of nearly equal parts of water and alcohol of the 
Specific gravity of 825.* : 
When the spirit is so much weaker, as to carry the whole 
of the graduated part of the stem above the liquid surface, 2 
weight is added, which causes the stem to be more or less 
: weight used in this case is marked 10> 
and to this number is to be added that observed on the stem, 
as before. On the scale, opposite the sum thus ascertained, 
will be found, the per centage above or below pr 
_ There are thirty-six weights, so proportioned, that, suppos- 
ing the instrument, in the first instance, placed. in alcohol, 
* According to Dr. Ure, the gravity of proof spirit, according to Dicas, is 
i. nial Ges Sdleanerree bY me, with one eonstructed 
a 
