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congratulated the Society on the improved state of their 
finances. 
The thanks of the Society, proposed by Professor 
BasBIncTon, and seconded by Professor SELWYN, were cor- 
dially accorded to him. 
Communications made to the Society : 
(1) On Carmine and the colouring principles of Cochi- 
neal. By Mr Rours, Jesus College. 
In most treatises on Chemistry it is stated that carmine is a 
compound of a peculiar acid styled carminic acid, and animal 
matter, to which for the purpose of giving body to the pigment 
alumina or oxide of tin are occasionally added. * 
Numerous receipts for its manufacture have been published ; 
in an early edition of “ Ure’s Dictionary of the Arts” there are 
several ; and it was from one of these that I hit upon the clue to 
the correct theory and practice of carmine-making. In all these 
receipts rain or distilled water, or river water are recommended 
to be used. With rain or distilled water I invariably found 
failure to attend my experiments, and with river water also, 
unless under peculiar circumstances. These circumstances were, 
the presence of a notable quantity of lime in the water, existing 
I believe in the form of carbonate of lime dissolved in carbonic 
acid. This led me after numerous experiments to devise the 
following method of making carmine (on the small way and for 
the use of artists and amateurs, though I see no reason why it 
might not be carried out on a larger scale) which yields a pig- 
ment of exquisitely pure scarlet tint and of a richness and 
brightness beyond any to be now met with in the shops. 
The first condition to be observed, is that the cochineal should 
be of the right sort. It should be by preference a Mexican 
black, or silver grey, hard and shelly, of rather a small starved 
shrivelled grain; not pasty when ground. The colour of the 
ground cochineal ought to incline to foxy red, and not to purple. 
