r 127 ] 
round hole at. top, and then covered with an aludel 
and luted ; this ferves to colledl the flowers and the 
fublimate which rifes. The fire is to be made under 
and all round the crucible. 1 1 tb. Troy of Aurum 
mofaicum may be made here at a time ; and when the 
operation is over, the bottom or round piece of burnt 
clay will eafily come out with the Aurum mofai- 
cum. A large crucible may be made ufe of, if a 
larger quantity be required to be made at once. The 
operation cannot fail of fuccefs, provided the fire be 
made of a fufficient ftrength, and of an equal degree 
from the bottom to the top of the crucible, which 
is eafily done in a good furnace. The operation is fini- 
fhed in eight hours, iinlefs the volatile liver is wanted. 
White arfenic, digelled with a folution of tin in 
the acid of fait, becomes foon black ; it does hereby 
regain its phlogiflon, and is reduced to the {fate of 
regulus of arfenic, and will by this means readily 
combine with copper, and other metallick fubfiances; 
which it would not do, without the help of phlogif- 
tic fubfiances. This is the moft eafy and ready way 
of reducing arfenic to its metallick form : the arfenic 
may be deprived of the folution of tin, which ad- 
heres to it by wathing it with water. It is to be 
dried flowly, for otherwife it is apt to catch fire. 
A Method of dying Wool and Silk, of a yellow colour, 
with Indigo and alfo with federal other blue and ' 
red colouring Subfances. 
THE Saxon blues have been known for feme 
dinej and are made by difiblving indigo in oil of. 
1. vitriol,, 
