1821.] Scientific Intelligence. 317 



Sulphuric acid 19"1 



Cinchonin 63 5 



82-6 



100 subsulphate of cinchonin, first crystallization : 



Sulphuric acid 113 



Cinchonin 79'0 



90-3 



100 subsulphate of cinchonin, third crystallization : 



Sulphuric acid 10'0 



Cinchonin 80 9 



90-9 

 (Annales de Chimie etde Physique, torn. xvii. p. 320.) 



IV. Purification of inferior Brazil floods. 



Dr. Dingier observes, that the true Brazil wood being extremely 

 scarce and dear, it may be interesting to state a method of substituting 

 inferior kinds for it ; those enumerated are Bois de Bimas, Sainte- 

 Marthe, d'Aniola, de Nicaragua, de Siam ou de Sapan, &c. These 

 woods contain fawn-coloured matter, which deteriorates the lustre of 

 the red ; this inconvenience is remedied by the following process : The 

 rasped woods are to be boiled in water until all their colouring matter 

 is dissolved. The decoction procured is to be evaporated until it equal 

 to about 12 or 15 times the weight of the wood employed. In about 

 12 or 18 hours after the evaporated liquor is cold, skim milk, equal in 

 weight to half the quantity of wood used, is to be added to it. When 

 the mixture has been well stirred, it is to be boiled for a few minutes, 

 and then strained through a fine piece of flannel. It will be then seen 

 that the fawn colour will attach itself to the cheesy matter of the milk, 

 and it is afterwards precipitated, without occasioning the slightest loss 

 of the red colour. 



In order to employ the liquor thus obtained in dyeing, it is to be 

 merely mixed with a proper quantity of pure water ; but if it is to be 

 used for printing calicoes, it must be further evaporated ; so that one 

 part of wood shall yield only five or six parts of decoction. To this is 

 to be added some starch, or other substance, to thicken it properly, 

 and a sufficient quantity of solution of tin, or some other base, to 

 brighten its colours. When printed, the colour is nearly or quite 

 equal to that of the true Brazil wood. 



The quantity of skim milk employed must always be in proportion 

 to the quantity of colour contained in the wood made use of; one-third, 

 or a fourth, of their weight will be sufficient for young woods, as they 

 are poor in colour. The evaporation must also be regulated by the 

 same principle, when intended for printing. — (Annales de Chimie etde 

 Physique.) 



