348 

 THE ANALYSIS. 



100 grains of the pulverized substance was heated with 200 grains of caustic 

 pot-ash, in a silver crucible. The mass was then dissolved by 12 ounces of 

 distilled water, and filtered. 



B 



To the solution A, nitric acid was added, as long as a pecipitate formed. 

 It was then further diluted, boiled, and filtered. The precipitate obtained 

 dried at 212, weighed 126 grains Cheated to redness, 110 grains. 



As the precipitate B might contain a small portion of the pot-ash, it was 

 boiled with 200 grains of marine acid, diluted, and filtered; when heated to 

 redness, weighed 94 grains. 



The filtre of the process A contained no extraneous matter. The solution 

 of nitrate of pot-ash B, being completely neutralized, was crystallized ; and 

 from the mother liquor a precipitate of silex was obtained : weighed 1.5 grain. 



E. 



The solution of muriatic acid c was neutralized by carbonate of pot-ash, 

 and boiled, and proved free from precipitation. 



100 parts of opal wood contain 



Grains. 



Silex ... c 94 



D 1.5 



Loss . 4.5 



100 



. Anxious to have the presence of carbon, in the opaline wood, still 

 more plainly manifested, I again troubled Mr. Pepys; the result of 

 whose obliging and ingenious labours I shall give you, in his own, 

 words; only omitting his well-adapted contrivance, for conducting 

 bis experiment with security and effect. 



