234 | New Salts crystallized without Water. 
NEW SALTS CRYSTALLIZED WITHOUT WATER. BY THE SAME. 
It was formerly believed that the water of crystallization was 
essential to the crystalline form of salts ; and it was even thought 
that all salts were provided with it: now, however, it is known 
that those salts which in their ordinary crystallization take the 
most of that water, can be crystallized independently of it, and 
crystallized even better. 
If we dissolve by fire in its water of crystallization some Glau- 
ber salt, and add as much of the same salt effloresced as the so- 
lution will take, crystals will make their appearance of a form 
different from that of the Glauber salt, and that even when the 
solution is still at a temperature of 45° Reaumur. These cry- 
stals consist of the Glauber salt totally deprived of water, of 
which that species of salt contains about one half of its weight. 
Let a little water then be added, and the whole allowed to cool, 
when a salt will be crystallized which is a combination in deter- 
minate proportions of salt without water and ordinary salt. 
Following the same operation with salt of soda,the refrigeration 
will produce in the mixture some large crystals, which will neither 
effloresce in the air nor imbibe any water, and which consist of - 
subcarbonate of soda wholly free from this liquid, being formed 
of 294 parts of soda and 21 parts of carbonic acid; and having 
thus, in the same weight, more than double the real matter, 
for the crystallized soda ordinarily incloses a third more than the 
equal of its weight of water. The soda from the coasts of Africa, 
which are washed by seas holding this alkali in solution, seems to 
be in the same situation, since it does not effloresce, a change 
which never fails to take place if it contains water. It is accordingly 
attended with a profit of more than one half to purchase this 
salt in preference to the other, when it can be had at the same 
price. The speculation might even be tried of crystallizing it 
after having dissolved it in water. It will take for 514 of this 
substance 664 of the liquid, and will augment in that proportion 
its weight. 
Many other salts crystallize without water ; and among others, 
marine salt, saltpetre, and sulphate of potash. Water cannot 
therefore be considered as essential to this operation, nor ought 
it to be termed water of crystallization, It is a new body com- 
posed of water and salt which is formed, and which ought to re- 
ceive a particular name. The name of hydrate which has been 
given to these compounds, and which has been extended to com- 
binations of water with the alkalies, the insoluble oxides and acids, 
is improper, inasmuch as it presupposes that in these different _ 
combinations the water always saturates as an acid, while in 
those with the acids it evidently saturates as an oxide. In every 
case 
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