COLOFBING MATTEES IN WINE. 227 



them, capable of combining with colouring matter. 

 Moreover, the colours of wines depend not only on the 

 existing apothema of tannic acid, but more especially 

 upon the greater or less solubility of the red colour- 

 ing matter, therefore upon the greater or less alcoholic 

 contents of the wine in combination with larger or 

 smaller contents of free acids, or cream of tartar. I 

 have confined myself to the properties of the colour- 

 ing matter of wine as it appears when dissolved in 

 tartaric acid and alcohol, in order to explain more 

 particularly its relations with wine. 



Colouring matter, when extracted from Burgundy, 

 Bordeaux, and Port wine, exhibits precisely the same 

 properties. The amount found in various kinds of 

 wine varies greatly. A few bottles of ordinary 

 Bordeaux furnish enough to allow its reaction to be 

 studied, though if prepared in the manner indicated 

 above, loss is sustained both when the liquid is filtered 

 from the precipitate by sugar of lead, and when the 

 sulphide of lead obtained from the precipitate of 

 sugar of lead is washed with water ; the loss being in 

 this case occasioned by tartaric acid, which has become 

 free. 



I have convinced myself that no other red colour- 

 ing matter can be found in these two liquids than 

 what can be extracted from sulphide of lead by means 

 of alcohol and acetic acid. 



I must remark in concluding, that the colouring 

 matter if prepared in this manner may easily have 



