110 
ON ARTIFICIAL AVENTURINE. 
have become as clear as if it had been filtered. It contains 
the carmine in suspension. The liquor is then decanted 
into a similar pan, and placed on the fire, adding the isin- 
glass dissolved in a considerable quantity of water and 
strained. At the moment of ebullition, the carmine rises to 
the surface, and a coagulum forms as in clarification with 
white of egg. The pan is then removed from the fire, and 
the liquor stirred with a spatula. After a quarter of an 
hour the carmine will be deposited, when the liquor is to 
be decanted and the deposit drained on a strained filter, and 
dried in the manner already described. — Ibid. 
ART. XXXVI. — ON ARTIFICIAL AVENTURINE. 
By Messrs. Fremy and Clemandot. 
Although the manufacture of coloured glasses has been 
but recently introduced into France, it has recently been 
brought to such great perfection, that the gems produced by 
our manufacturers will, in many cases, bear comparison 
with those of Bohemia. 
There is nevertheless a production of this class which had 
not as yet been manufactured in France; we allude 1o the 
artificial aventurine, which has hitherto only been made 
in Venice, and the manufacture of which is kept a profound 
secret. Fine specimens of Venitian aventurine are very 
scarce, and are sold at as high a price as 200 francs the 
kilogramme. 
We were anxious to discover the mode of making this 
gem, and of giving the benefit of the discovery to our glass- 
workers. 
After numerous experiments which have been conducted 
at the glasshouse of Clichy, we have been fortunate enough 
