100 On definite Proportions. 
of sulphuric acid and 50°48 of the base, it contains, when ciy- 
stallized, Sulphuric acid.... 30°965 
Protoxide of zine.. 32°585 
Water ais oaitvelacte ae aao 
The base contains 6°39, and the water 32-15 parts of oxygen ; 
but 6°39 x 5=31-95 : consequently the water contains five times 
as much oxygen as the base. 
Sulphate of the oxide of copper. Ten grammes of this salt 
in crystals lost, when dried to a powder over a spirit lamp, 36:3 
percent. in weight. The crystallized sulphate of the oxide of 
copper consists therefore of 
' Sulphuric acid .... 31-57 
Oxide of copper... 32°13 
Water ...: 2.53... 36°30 
since, according to the corrected analysis of the sulphate of baryta, 
5 grammes of the sulphate of copper consist of 2°477 gr. or 49°55 
per cent. of sulphuric acid, and 50°45 per cent. of oxide of cop- 
per, or 101-82 parts of oxide of copper for 100 of sulphuric acid. 
The oxygen of the oxide of copper, being computed at 24:5 per 
cent. amounts to 6°32, and that of the water to 32: but 
6°32 X 5 =31°6; so that the water of erystallization contains 
jive times as much oxygen as the base. 
Nitrate of the protoxide of Lismuth. Ten grammes of this 
salt, crystallized, and dried in the air after being powdered, were 
heated in a small retort to complete ignition. They afforded in 
one experiment 5°13, and in another 5-12 grammes of liquid 
nitric acid, not smoking. Consequently this salt must contain 
more water than is sufficient to exhibit the acid in its highest . 
state of concentration. According to the very accurate experi- 
ments of Mr. Lagerhjelm, the protoxide of bismuth contains 
10°13 per cent. of oxygen; 48:8 parts must therefore contain 
4-9434, and must consequently saturate S3°7 parts of nitric acid, 
{since 100 parts of nitric acid suppose 14% of oxygen im the base 
which saturates them. G.] The remaining 17°5 parts, which 
make up the 100, must have been water. But these contain 
15:4 of oxygen; and 4:9434 x 3 = 14°83. We see therefore 
that, according to this experiment, which cannot be very accurate, 
frem the readiness with which the atmospherieal moisture de- 
composes the salt, the water of crystallization must. contain /hree 
times as much oxygen as the base. 
. 
Conclusions. 
I consider these examples, for which salts of so different na- 
tures have been selected, as sufficient to demonstrate the law, 
that ‘the oxygen of the water of crystallization is always an in- 
tegral 
