"88 CHEMICAL JN ALTS IS 



fiance *. He has not mentioned the circumftance in any of his 

 works; but Dr Black has been accuftomed, as he informed me 

 himfelf, to take notice of it in his ledlures on chemiftry, for 

 many years. It is my intention to analyze fome fpecies of zeo- 

 lite ; and if the refults feem of any importance, they fhall be 

 laid before the Society. 



Amon g the experiments on the bafalt of StafFa, already de- 

 fcribed, it has been obferved, that, when the powder was boil- 

 ed in water, a flight precipitate was produced in the water by 

 nitrate of filver, thus indicating fome traces of muriatic acid. 

 As it appeared of importance to determine how much of this 

 acid the bafalt contained, I fubjeded fome of it to examination 

 for that purpofe. 



Experiments to a/certain the ^mntity of Muriatic Acid in the Ba- 



fait ofStaffa. 



One hundred grains of the ftone, in fine powder, were mix- 

 ed in a fmall retort with fome nitric acid ; and a receiver being 

 adapted, the mixture was boiled gently, till the greater part of 

 the acid had diftilled over. The liquor in the receiver being 

 examined with nitrate of barytes, remained unaflfedled ; but 

 gave a flight cloud with nitrate of filver, which Ihewed that ic 

 contained fome muriatic acid. 



The mafs in the retort being diluted with water, the whole 

 was filtered ; and this filtered liquor produced no cloud with 

 nitrate of barytes, but gave, like the former, a flight precipitate 

 with nitrate of filver. 



In 



* In the 26th volume of the Annalts de Chimie, p. 119. M. Scherer, in a letter 

 to Van Mons, fays, that he was informed by Dr Black, that Dr Hdtton had, 

 long ago, found potajh in zeolite. In this ftatement M. Scherer is incorreft) be- 

 caufe it was foda, as above mentioned, which Dr Hutton obtained from that fubftance-. 



