234* OBSERVATIONS ON MURIATIC ACID. 



parts of the fame fait that hsd not been expofed to fire. A 



violent heat may be neceifary to expel the lait portion of water 



of cryftallization from certain falts, as we know particularly 



Whence the wt- i s the cafe with fulphate of lime. But, if any of the acid can 



ter ot cryftalu- , „ , _.'■•; , . . 



t ition i« inac- De opened at the lame temperature, there is no longer any 



curately deter- certainty. The quantity of water, as ftated by different che- 



jf'the acid of J ™ft s > varies much ; and, from fome experiments I have 



the fait be de- made, I do not believe it to have been accurately determined, 



terminedby The method I ufed to afcertain this, was as follows: I ex- 

 precip. with fil- 



ver before and pofed a given quantity of the fait to a violent heat, and noted 

 after ignition, it [ is j f 6 f we ight. I then precipitated, by nitrate of filver ; 

 may be known ."..", , , , . r . . . , , . , 



how much of and thus knew, how much the quantity ot muriatic acid which 



the lofs by the this fait contained, was lefs than that in a like portion which 



aeVd^anThoV' ^ad not been expofed to heat. I fubtra&ed the difference in 



much water. this quantity, from the total lofs of weight in the fait expofed 



to heat ; and the remainder I confidered as water. It was 



upon reful ts obtained in this manner, that I founded many of 



the proportions I have given in this Paper, 



Obfervations on It is itated in the tables of Bergman, corrected by Dr. 



tunfe" aitrae " Pearfon, that lime and ftrontia prefer acetous to arfenic acid. 



But arfenic acid can expel hyperoxigenized muriatic acid from 



its bafisj although the acetous cannot aft in the fame manner ; 



therefore, this order of affinities is erroneous. It was not till 



lately, that we had potaih and foda fo pure as to be relied 



upon in delicate experiments ; and it is not furprifing that we 



find miftakes with regard to their taking the acid from barites, 



itrontia, and lime. But real potafh and foda both precipitate 



even barites from hyperoxigenized muriatic acid. If ever it 



becomes eafy to obtain hyperoxigenized muriate of barites, 



we may prepare that earth from it in the humid way, and 



more near to purity, than in the method propofed by Vau- 



quelin. 



Metallic mum- METALLIC COMBINATIONS OF MURIATIC 

 ticfalts * ACID, IN ITS DIFFERENT STATES. 



The action of hyperoxigenized muriatic acid upon metals, 



is, as may well be expected, rapid, and without difengage- 



Hyp.ox. mur. mentofgas. It appears to diflblve every metal, not except- 



ariddiffolves all • y and p i at i na . If the metal be prefented to the acid 



metals: inflames °° , .,-,./- , r . r 1/ • a 



them and pro- at the moment when it is Unengaged from the lalt, intlamma- 

 duces muriates, tion enfues ; and the phenomena of light and heat vary ac- 

 cording 



