upon oxygenized and hyperoxygenized muriatic Aci d } &c . 351; 
may have been stated. It is impossible to obtain satisfactory 
crystals from a very small portion of salt; and I have at- 
tached myself more particularly to chemical than to physical 
characters, as being a much more important and certain mode 
of determination. For the same reason, I have not exa- 
mined the combination of the new and rarer earths with this 
acid. But I do not doubt, that whatever chemist undertakes a 
further investigation of these extraordinary bodies, will be amply 
repaid for his labour. 
I have mentioned, in a former part of this Paper, that all 
muriates lost a portion of their acid at a red heat. I exposed one 
hundred parts of muriate of potash, in a crucible, to a red heat, 
for some minutes, and found that they lost five. I dissolved them 
in water, and they manifested = alkaline properties. Treated by 
nitrate of silver, they gave a precipitate, which shewed one per 
cent, less of muriatic acid, than 100 parts of the same salt that 
had not been exposed to fire. A violent heat may be necessary 
to expel the last portion of water of crystallization from certain 
salts, as we know particularly is the case with sulphate of lime. 
But, if. any of the acid can be expelled at the same temperature,, 
there is no longer any certainty. The quantity of water, as stated, 
by different chemists, varies much ; and, from some experiments ; 
I have made,. I do not believe it to have been . accurately deter- 
mined. The method I used to ascertain this, was as follows: 
I exposed a given quantity of the salt to a violent heat,, and 
noted its loss of weight. I then precipitated, , by nitrate of 
silver; and thus knew, how much the quantity of muriatic 
acid which this, salt contained, was less than that in a like, 
portion which had not been exposed to heat. I subtracted the 
difference in This quantity, from the total loss of weight in the. 
