beaume's hydrometers. 
5 
the above sp. gr., each degree can be obtained by dividing the 
space, and their value determined by the equation j^-> enabling 
any one to prove the correctness of a hydrometer, and furnishing 
tables that cannot differ or contain any source of error. 
The pese esprit has suffered even greater changes. It is much 
to be regretted that the same modulus cannot be used for both in- 
struments, but it would produce so great a change if attempted, 
that the confusion arising from it would more than counterbalance 
its advantages. Beaume's 10 per cent, salt solution was used by 
him for the zero, (sp. gr. 1.0735,) and water for the tenth de- 
gree (sp.gr. 1.000,) of the scale. The formula = H, 
gives 146 as the modulus for his hydrometer. The table formed 
from this (the true Beaume's pese esprit,) differs entirely from the 
one now in use ; a comparison of several scales further on will 
show the change. 
The scale most frequently met with approaches the one formed 
from the modulus 140, and is the one given in Wood & Bache's 
Dispensatory, and from being so generally in use, is often con- 
sidered the standard; its modulus, however, is irregular and 
therefore erroneous. A curious fact connected with this scale, 
and which has probably led to its adoption, is the close cor- 
respondence with its values and those of Carrier's scale, 
as obtained by making 22° of Cartier's equal 22° of Beaume's 
original 146 modulus scale, and subdividing every 15^ Beaume 
into 16, (Cartier's plan.) Many of the higher numbers of the 
scale correspond exactly with the modern scale, (modulus 140) 
and all of them are within half a degree of being identical. It is, 
therefore, useless to publish tables for reducing Cartier to Beaume, 
the so-called Beaume's scale being in reality as near the original 
Cartier scale, as the different instruments made by Cartier himself 
were to each other. It is surprising that the above coincidence 
has escaped notice so long. Liebig and Poggendorf 's " Hand- 
woorterbuch der Chemie," contains tables placed near each other 
which almost coincide, and yet no notice is taken of it and the 
rule given to reduce the scales, when the reduction would only re- 
move them two or three degrees apart. 
To recapitulate, the position of the pese esprit at present is 
as follows. Beaume constructed a scale upon the modulus 146. 
1* 
