EXTRACTING COLOURING FROM DYE-WOODS. 191 
you with all I know. You are at liberty to publish or make 
what use you think proper of this communication. 
I may add, that this substance will be introduced into the 
next edition of the "Prussian Pharmacopoeia." — London 
Lancet. 
ART. XXXVI I.— NEW APPARATUS FOR EXTRACTING THE 
COLOURING FROM DYE WOODS. 
By M. Iwan Schlumberger. 
At a meeting of your committee of chemistry I communi- 
cated the advantages which I had found in the apparatus of 
Mr. Meissonnier, for extracting the colouring matter of log- 
wood. Some members appearing to doubt the real merit of 
this apparatus, from not having produced results analogous 
to mine, on trying it, I made some fresh experiments, which 
I explained to your committee of chemistry, accompanied 
by calculations which any other person might make. 
It is of some of these experiments I am now about to 
speak. 
In order to make decoctions of logwood, the usual method 
is, to put a quantity of shavings of that wood into a boiler 
in immediate contact with the fire, together with a quantity 
of water, sufficient to cover the wood completely, so that 
after boiling for some hours the wood may be quite covered. 
The operation is renewed twice with the same liquor, and 
after three successful boilings, the decoctions are mixed to- 
gether and evaporated to the degree required. 
This operation is attended with several disadvantages. 
Shavings only can be employed, for if the logwood be re- 
