into corresponding 'Expression of Specific Gravity . 8 ? 
ter, and the height to which it floated was marked on the 
stem as 15° of the scale. The interval between these 
two points of immersion being therefore considered as 
15 degrees, the scale was extended to any required num- 
ber, merely by marking off with compasses an equal 
length of the stem, and the whole was farther subdivided 
in the same w ay. Beaume considered therefore that eve- 
ry degree of the instrument indicated a density of liquid 
equal to that of a solution of common salt, in which the 
number of parts of salt in 100 parts, by weight, of the 
solution, was equal to the same number on the scale at 
w hich the instrument floated. But as the diameter of the 
stem is seldom equal throughout, he proposes to remedy 
the incorrectness produced by this circumstance, where 
greater accuracy is required, by immersing the instru- 
ment successively in solutions containing 5, 10, 15, &e» 
per cent, of salt, and marking these points as 5, 10, 
15, &c. on the scale, or, to be still more accurate, all the 
individual degrees may be found by actual experiment. 
In fact, even where the stem of the instrument is per- 
fectly cylindrical, this would be the only way to ensure 
perfect accuracy, as a division of equal distances on the 
scale would not precisely correspond with an equal in- 
crease of percentage of salt in the solution. 
The scale of this instrument does not properly extend 
higher than about 30®, as this is the point of saturation 
of water with salt, but it may be lengthened at pleasure 
by marking off equal distances on the scale. 
The following table of correspondence between Beau- 
me ? s areometer for salts and the actual expression of spe 
cific gravity has been calculated by Mr. Nicholson, for 
every third degree (Phil. Journ. 4to. vol. i. p. 38.) from 
the datum of Morveau that the 66th degree corresponds 
with 1.848 sp. gr. We have added to it the specific 
gravities of most of the corresponding solutions of com 
