OBSERVATIONS ON MURIATIC ACID. 233 



foluble in alcohol ; but I could not afcertain the proportion of 

 its principles, becaufe I did not obtain it fufficiently free from 

 the fimple muriate. 



Ninth Species. Huperoxisenized Muriate of Silica. Hyp. ox. mut, 



1 Jl * filica docs no^ 



I am inclined to think this fait does not really e xifr. A cur-exift. 



rent of oxigenized muriatic acid, fent through fome filica 

 which had been precipitated from an acid by ammonia, and 

 collected moift from the filter, did not feem to diffolve any 

 portion of it. In all barites and ftrontia, prepared according 

 to Mr. Vauquelin's method, a portion of filica from the cruci- 

 bles is attacked, and taken up, by whatever acid thofe earths 

 may afterwards be diffolved in : and, in all potafh of com- 

 merce, there is fome filica; but I have never perceived that 

 any portion of this earth had been diffolved by this acid. 



The very fmall portion of earth which, in attempts to form General obfenr. 

 Jhe different fpecies of this genus of falts, is taken up by acids, h ox. mur 

 and the ftili fmaller portion of the fait fo formed, which is 

 jeally in the ftate of hyperoxigenized muriate, render the ope- 

 ration fo tedious, that I have confined myfelf to form what 

 was neceflary to determine their analyfis, in fuch a manner as 

 1 believe to be nearly accurate. It cannot, therefore, be ex- 

 pected that I make myfelf refponfible, without a right of ap- 

 peal to further experiments, for the accuracy with which the 

 cryftalline forms, and other phyfical properties, may have 

 been ftated. It is impoffible to obtain fatisfactory cryfials 

 from a very fmall portion of fait; and I have attached myfelf 

 more particularly to chemical than to phyfical characters, as 

 being a much more important and certain mode of determi- 

 nation. For the fame reafon, I have not examined the com- 

 bination of the new and rarer earths with this acid. But I do 

 not doubt, that whatever chemift undertakes a further invefti- 

 gation of thefe extraordinary bodies, will be amply repaid for 

 his labour. 



I have mentioned, in a former part of this Paper, that all A11 muriates 

 muriates loft a portion of their acid at a red heat. I expofed by ignition. 

 one hundred parts of muriate of potafh, in a crucible, to a 

 red heat, for fome minutes, and found that they loft five. I 

 diffolved them in water, and they manifefted alkaline proper- 

 ties. Treated by nitrate of filver, they gave a precipitate, 

 which mewed one per cent, lefs of muriatic acid, than 100 



parts 



