ANALYSIS OF F;LUOR>SPAft. J^y 



XL 



On Muriatic and Oximvriatic Acid, in Answer to Justus* 

 In a Letter from Mr. John Dalton. 



To Mr. NICHOLSON. 

 SIR, 



JL OLTR correspondent who signs himself Justus in your 

 last number seems to possess considerable acquaintance ^" "*"!"'^*'*^ 

 with the subjects of his animadversion ; but in regard to ticacid. 

 oximariatic and muriatic acid at page 72, his data are de- 

 fective, and the principles of his calculations are to me alto- 

 gether unintelligible. If he will explain the manner of his 

 CHlculatiou, I shall probably on some future occasion reply 

 to liis different inquiries and observations. 



I remain, yours, 



J. DALTON. 



Manchester y Jan, '2.0th, 1811. 



XIL 



An Analysis of FluorSpar, By Thomas Thomson, 

 M. D. F. R. S. E*. 



J[^ HE mineral called fluor-spar has been long known, and Fluorspar 

 valued on account of its beauty, and the ease with which it 

 can be turned on the lathe into various ornaments and use- 

 ful utensils. It occurs chiefly in veins, and very frequently 

 accompanies lead ore. Some of its properties have been 

 described more than a century ago, as, for example, its 

 phosphorescing when heated, and its corroding glass when 

 mixed with sulphuric or nitric acid. But it is not forty 

 years since its composition was discovered by Scheele, who 

 demonstrated, that it is composed of lime, and a peculiar 

 acid, called fluoric. Chemists now distinguish it by theorftuateof 

 nameof fluate of lime. ^""^• 



Hitherto, no chemical analysis of this salt has been pub- No accurate 

 Hshed, except a very incorrect one by Kirwan and Gren, ^^'^'y^*' ^* '* 

 which has been ascribed to Scheele, though I cannot find 

 it in any of his dissertations on fluor-spar. By that analysis, 

 it is made to contain 27 per cfwf of water, a proportion very 

 inconsistent with the properties of native fluate of lime, 



* From the Txansactions of ihe Wernerian Society. 



which 



