1817.) On Chinese Mercurial Preparations. 347 
operator inverted a glazed earthenware bowl over them, of such 
diameter as to leave about an inch of the edges of the pan over its 
rims. He heaped salt round the sides and over the bottom of the 
bowl, upon which he placed a brick. When nitrous acid vapours 
began to rise through the salt, he appeared at first desirous to stop 
their egress by adding fresh salt, after which he paid no further at- 
tention to them. By additions of thoroughly ignited pisces of char- 
coal he kept up a considerable degree of heat under the tatch for 
apwards of two hours ; when, having filled his furnace with pieces 
of charcoal, he said it might be allowed to burn out, and the vesse!s 
to cool. Next morning, when the brick and salt were removed, the 
nitric oxide was found closely adherent to and crusting the inside of 
the bowl. When all was scraped off and collected, it weighed 
1440 grains. 
The object of the following process appeared to be to obtain a 
sulphuric oxide of quicksilver ; but, as the specimen will show, it 
was but imperfectly fulfilled, owing to the mixture of the oxide 
which it contains. The ingredients for this preparation were— 
Sulphate of alumina .........+..-- eee soa.) OU re 
Sulphate of iron...... oy SHEA Stes abil or Pty va ¥ 2 
Sulphuret of quicksilver ........ aT ¢ 8, basta sheets ee, eRe 
Witrate of potash .........-.2--e+.0- bonis: 2400 
The yellow sulphuret before mentioned ........ 310 
SROMIAIVET | pink sfoginsiscigm a= gin naaelt wean 7 piers 930 
The nitrate of potash which he used upon this occasion was re- 
markably well purified. He fused the ingredients in the same kind 
of vessel described as having been used in the last process thoroughly 
heated beforehand, by having stood on the fire ; and having added 
the quicksilver, he inverted the glazed bowl over the contents of the 
pan, and covered it round the sides and over the top with an earthy 
powder of ared colour, which he brought with him, and which he 
informed me was the powder of foliated gypsum, and, by having 
been often employed in the same process, derived its red colour 
from the fumes which had passed through it. Over the top he 
placed a brick. A strong fire was kept up under the pan during two 
or three hours, after which it was allowed to burn out. The appa- 
ratus was removed next morning, when the bottom of the bow] was 
found crusted with a red oxide; the other part, the rims and surface 
of the matter adherent to the pan, with a yellow one, which he 
scraped off, and which weighed 680 gr. He did not consider the 
process as having been successful, from the admixture of red oxide 
with the yellow one, which it was his object to obtain solely, and 
was desirous to repeat the process; but as he proposed no variation 
- the circumstances or conduct of it, I did not trouble him to 
0 80, 
