Rowley-rag-fWie and the Toad-ftone. 331 
until the whole was wafhed away. The warnings were then 
filtered, and the powder carefully collected and dried. The 
water employed in the wafhings did not appear to have diffolved 
any part of the ftone ; for no precipitate was formed either 
upon the addition of mild fixed alkalv, or of fiver difiblved in 
the nitrous acid. 
C. 100 parts of this powder were put into a fmall mattrafs, 
and covered with marine acid : a degree of heat , was excited, 
and a very fight effervefcence took place. Water was then 
added, and the mixture kept boiling for half an hour. The 
liquor was decanted off, and more acid added, which was boiled 
as before. This was decanted, and the reiiduum wafhed with 
water until the water came off taffelefs. Thefe waters were 
added to the liquors before decanted. The powder had now 
an afh-coloured appearance, and when dried weighed 80 
To the liquors (C) phlogifticated fixed alkaly was added, 
until no more Prufliati blue was precipitated. To eftebt this 
it took one ounce, five drams, and twelve grains of the phlo- 
gifticated alkaly. The precipitate, when wafhed and dried, 
weighed 47. 
E. The powder of 80 \ (C) mixed with twice its weight of 
foffile fixed alkaly, was put into a black lead crucible, and ex- 
pofed to a red-heat for two hours. The heat was never iuffi- 
cient to render the mals fluid, nor to make it adhere firmly to 
the crucible. The faline part waS then wafhed away by re- 
peated effufions of hot water. To the remaining powder 
marine acid was added repeatedly, and boiled as before. The 
powder was now perfectly edulcorated by hot water, and when 
dry weighed 47 f. 
The above liquors were all added to the liquor (C), and plilo- 
rifficated fixed alkaly was dropped in, until no more Prufiian 
X x 2 blue 
