198 
Dr . Thomson on some of 
its atomic weight will be 1 1 , and 1 1 grains of it will contain 
just the equivalent of 1 atom of chromic acid, and 1 atom of 
chlorine. The crystals of carbonate of soda being composed 
of i atom carbonic acid - - 2*75 
1 atom soda - - -4 
10 atoms water - 11*25 
18 
It is clear, that in order to neutralize 11 grains of the red 
liquid, we must employ 36 grains of the carbonate ; but 
11 : 36 : : 15*32 : 50*15 = quantity of carbonate of soda em- 
ployed. As this quantity just neutralized the liquid, it is 
plain that the quantity of acid in the red liquid was rightly 
estimated. 
If 11 grains of the red liquid contain 6*5 gr. chromic acid, 
15*32 gr. must contain 9*052 of that acid, which will require 
for complete precipitation 22*98 grains of nitrate of barytes. 
The liquid was freed from the trace of green oxide of 
chromium which it contained by filtration, and a solution 
of 22*98 grains of nitrate of barytes was mixed with it. After 
the chromate of barytes had subsided the liquor was colour- 
less, and was not altered by sulphate of soda. Consequently 
it contained no sensible quantity of chromic acid, or of barytes. 
It is plain that the quantity of chromic acid in the red liquid 
had been rightly determined. 
The liquid thus freed from chromic acid still retained its 
chlorine, which, if the constitution of the red liquid has been 
rightly determined, should amount to 6*268 grains, and 
would just require 29*94 grains of nitrate of silver to throw 
it down. This quantity was therefore dissolved in distilled 
water, and mixed with the liquid. After the chloride of 
