ON THE PREPARATION OF KERMES MINERAL. 237 
of carbonate of potash to each of the four series of opera- 
tions every five or six days, as the proportion of alkah 
diminishes, else the beauty of the product is impaired. 
*'The deposits from the difFerentlpots having been received 
every day into the same vessel, are thrown on to a cloth 
covered with filtering paper. When the liquid ceases to 
drop, the precipitate is washed with cold boiled water till 
free from adhering alkali, and afterwards enveloped in 
brown paper and dried at a temperature of 60° or 65° Fahr. 
It is very important that the temperature be very moderate 
and always equal, because experience has proved that 
without this precaution, the product is less beautiful. 
When sufficiently dried, ihe kermes is triturated in 
a marble mortar, passed through a silk seive, and pre- 
served in earthen pots or glass bottles, protected from the 
light. 
" We have repeated the process of M. Liance with the 
minutest exactness ; we have also thought proper to assist 
at an operation conducted by himself in the midst of his 
laboratory, and aided by its utensils, because we know that 
with all operators there are certain slights-of-hand in the 
success of the operation. 
In one or the other case by ourselves, or by M. Liance, 
we have obtained products that have appeared to us to 
unite all tha desirable qualities. Thus^the kermes yielded 
by this process is light, presents the beautiful colour that 
gives it name, and has the velvety aspect which is one of 
the essential requisites." 
The reporter further states that he has not investigated 
the part that is acted by the preparation of potassa, nor has 
he given a chemical comparison of the composition of 
Liance's kermes with that of Cluzel, as to their richness in 
oxide of antimony. He recommends that their relative 
therapeutic virtues should be tried by parallelj sets of ex- 
periments. 
Cluzel's process requires that one part of finelv powdered 
21* 
