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ON THE GRADUATING OF HYDROMETERS. 
2d. For liquids heavier than water. 
The specific gravity corresponding to 10° B., Pese acid being 
1.07407+ we have the following: as 1.07407 : 1 :: wt. of hyd., 
required wt. of hyd.=wt. of hyd. x '9310346 + ,and by subtract- 
ing this from the original wt., there remains wt. of hyd. X '0689654* 
+ , or *069 nearly, for the amount to be withdrawn, to enable the 
stem of the hydrometer to rise to the 10th degree of Beaume. The 
hydrometer in this case must be made , to sink to near the top of 
of the stem, which of course will be the zero point or 0° Beaume ; 
then by successively taking out the proper quantity of mercury, 
as shown above, (wt. of hyd. X *069) the divisions, corresponding 
to each 10° B., are noted down as the stem rises. In practice it 
will be found much more convenient to get the 70° B. first by 
taking out seven times the above quantity, and then by restoring 
successively the seventh part of the amount taken out, to mark the 
divisions as the stem sinks. The scale is then to be finished as 
usual. 
Hydrometers can be graduated in a similar manner, for show- 
ing directly the specific gravity of any liquid, by using the fol- 
lowing formula : Weight of the hydrometer when sunk to the 
proper depth, divided by the specific gravity required, the quo- 
tient will give the required weight of the hydrometer ; if this is 
less than its actual weight, the difference is to be withdrawn ; if 
greater, the difference is to be added. It will be necessary, as 
the degrees will vary unequally, to determine the divisions of the 
scale for every 5, 10 or 20 grs. (water reckoned 1000) according 
to the accuracy required. 
It will be evident that alcoholometers and others of a similar 
character, can readily be graduated by the same formula, marking 
off the specific gravities corresponding to each per cent, of alco- 
hol. As the percentage by volume and percentage by weight 
varies considerably, it should always be stated on the scale which 
of the two the instrument is intended to indicate. 
Philadelphia, N. E. corner Passyunk road and Catharine street. 
* The ratios which the excess or deficiency bears to the original weight 
of the hydrometer gives the modulus of the scale as recommended by Mr. 
Pemberton: thus for the Pese acid 1 -f- -0689654 -f =145, and for the 
Pese esprit 1 -f- 0-714285 + =140. 
