1817.] On Chinese Mercurial Preparations. 351 
It was in soft, silky scales. ‘l'asteless; and insoluble in water. 
Before the blow-pipe it evaporates rapidly in a white smoke. 
When digested in sulphuric acid, no smell of acetic acid is 
given out. I was induced to try this experiment, because the sub- 
stance very much resembled acetate of mercury in its appearance. 
I digested 3 gr. of it ina solution of 3 gr. of bicarbonate of pot- 
ash in distilled water. The scales soon disappeared, and a greyish- 
white powder remained undissolved. The solution was poured off, 
and the residue edulcorated with distilled water. Diluted nitric acid 
was poured on the residue. A slight effervescence took place, a 
portion was dissolved, and a portion remained, having exactly the 
scaly appearance, colour, and lustre, of the original salt. By re- 
peating this process three times, | decomposed and dissolved the 
whole matter, except about , gr., which I neglected. After the 
last digestion in bicarbonate of potash, the residue was black, Thus 
I combined the acid of the salt with potash, and the base with 
nitric acid. 
The nitric acid solution was not affected by infusion of nutgalls ; 
but it was precipitated white by prussiate of potash and by sal-am- 
moniac. ‘These properties, together with the volatility of the ori- 
ginal salt, show clearly that the base of the salt.is mercury; and as 
it is left black by the bicarbonate, we may conclude, I conceive, 
that the mercury is in the state of protoxide. 
The bicarbonate of potash solution (containing the acid) was satu- 
rated with acetic acid, evaporated to dryness, and the residue dis- 
solved in distilled water. With this solution, I tried the following 
experiments :— 
Nitrate of lime .......... Occasioned no change. 
Muriate of barytes........ A white precipitate, not redissolved by 
nitric acid, but nearly so. 
Nitrate of strontian ...... A white precipitate. 
Sulphate of magnesia...... O. 
Nitrate of lead .......... A white precipitate, redissolved by 
nitric acid. 
Nitrate of silver.......... A white precipitate. 
Nitrate of mercury ...... A white precipitate. 
Proto-sulphate of iron .... O. 
Persulphate of iron ..... . @. 
Sulphate of copper ...... O. 
It is clear, from the inefficacy of nitrate of lime, that the acid is 
not the oxalic. ‘To determine whether it might be the tartaric or 
citric, 1 made the folowing comparative trials :— 
Effect of Re-agents on Tartrate of Potash, 
Nitrate of lime .......... A dense flocky-white precipitate. 
Muriate of barytes........ Ditto. 
Nitrate of strontian ...... Ditto, 
Sulphate of magnesia .,., O. 
