184 



Intelligence and Miscellanies. 



naked eye, or easily rendered so by a slight degree of fric- 

 tion witli my finger ; the pressure attending which could 

 only have brought already existing uncombined particles 

 within the sphere of each otlier's attraction. When calomel 

 (protochloride of mercury) is decomposed by an alkaline so- 

 lution, if the latter be cautiously dropped upon it, a reddish 

 powder is at first apparent.* This fact and the subsequent 

 evidence of the existence of metallic mercury in the pov.der, 

 may serve to explain each other. A muriate of the alkali is 

 formed at the expense of a portion of water, and the oxygen 

 being left to the free exercise of its affinity, forms with half 

 of the metal — a binary compound — the red oxide, through 

 which the remaining proportional of mercury, in a state of 

 extreme comminution, is mixed. The powder will be found 

 capable of amalgamating gold, and the uncombined metal 

 may be rendered evident, by friction, percussion, or elevation 

 of temperature, or by pouring upon it a minimum quantity 

 of diluted acetic acid. The supernatant liquor will contain 

 peracetate. 



I do not know that more conclusive evidence of an error 

 in the atomic weight of any body could be adduced. An- 

 nexed is a table of the corrected atomic weights of a few of 

 the mercurial combinations. 



Samuel Allinson, Jun. 



Philadelphia, llmo. 11th, 1828. 



* A careful repetition of this experiment has placed its accuracy beyond a 

 doubt. On calomel, (prepared by precipitation from a solution of crystallized 

 protonitrate of mercury, with muriate of soda) which was repeatedly washed 

 with warm distilled water, with solution of muriate of ammonia and with warm 

 alcohol, I dropped a small quantity of potass water. A reddish powder was 

 very distinctly observable. When sufficient alkali was added to decompose all 

 the calomel, the powder was of a brownish black color, and when dry contain- 

 ed visible globules of metal. This shows the fallacy of one of the reputed tests 

 for the purity of calomel. 



