i ft ANALYSIS OF LITHOMARGE. 



to the precipitate, to afccrtain the true weight 

 of it *. 



To examine the other half of the folution, the 

 phlogifticated alkali was employed ; and from 

 it was obtained 12 Ib. of blue icdimcnt, con- 

 taining 2 of iron in its metallic Hate, and 2.7 

 of the calx of that metal. In a hundred weight 

 therefore, there is 5.4 Ib. of ferruginous matter, 

 befidcs that portion to which the liliccous earth 

 owes its colour. 



The liquor being puffed through a filtre, con- 

 tained argillaceous earth, magneiia, and chalk, 

 all combined with the vitriolic acid; but we 

 were now inquiring after the firil only. To the 

 folution, then, reduced to the bulk of fix cubic 

 inches, and heated to 90 degrees of the Swedilli 

 thermometer, was added gradually as much ae- 

 rated magnefia as would be fuilicient to dcilroy 

 entirely the excels of acid, fo that the paper 

 flained with the turnfolc gav^ no lign of any 

 remaining unfaturatcd. In order that the quan- 

 tity of nujgnt fia JLould not exceed the proper li- 

 mits, every bit thrown in was fullered to diilulvc 

 bcfore more was added. The futuration being 

 then compleated, the liquor was boiled for half 



an 



* Calcareous earth is precipitated by the faccharatcd fxcil 

 vcg. alkiili. As laccharatcd ma^nefia remains tlillulvtii it; an 

 excefb of acid with pure argillaceous earth; it ib therefore to be 

 m.'ulc perfectly dry by rutlAtiig ; and in 01 Jcr t- Jcilrov the 

 *cM cf fj^ur, mull Lc bur:il in A ilron^ lire. 



