284 VEGETABLE SUBSTANCES. 



nature and properties being exactly the same. Good 

 tartar is thick, brittle, brilliant, and contains but little 

 earthy matter. It is used in dyeing, hat-making, 

 gilding, and other arts. 



Argol is distinguished in commerce as coming 

 from Bologna, Florence, Naples, and Sicily, and 

 from the Cape of Good Hope. After the German, 

 that coming from Bologna is the best, its price 

 averaging from 66s. to 70s. per cwt. ; while that of 

 Sicily, which is the lowest priced, obtains not more 

 than 40s. per cwt. It is admitted at the trifling 

 duty of 2s. per cwt., and from British possessions 

 at only half that sum. 



The average annual quantity imported during the 

 five preceding years was 2,980 casks and cases, each 

 cask weighing ten cwt, and each case from two to 

 three cwt. 



Tartar contains much extraneous matter, which is 

 useless, or perhaps detrimental in the several uses to 

 which it is applied. It is, therefore, for some pro- 

 cesses in the arts employed in a purified state, and is 

 then called cream of tartar. The following is the me- 

 thod of obtaining the cream as pursued at Montpelier. 

 A saturated solution of tartar is made in boiling 

 water; as this water gradually cools, some of the salt 

 separates and forms into crystals. These crystals are 

 then re-dissolved in another vessel, with the addition 

 of a white argillaceous earth in the proportion of five 

 or six pounds to each hundred pounds of the crys- 

 tallized salt; the aqueous solution is then subjected 

 to ebullition. After this boiling a very white salt is 

 obtained by evaporation, and it is this salt that is 

 3tnown in commerce as cream of tartar. 



According to M. Desmaretz, at Venice white of 

 eggs and ashes are used instead of the earth; but. 

 it is said that this addition of ashes introduces 1 

 a foreign salt which affects the purity of the product. 



