ESSAY VII. 



REMARKS UPON SALT OF BENZOIN. 1775. 



THE common way to obtain the salt from benzoin is by 

 sublimation. This salt is sold in the shops under the name 

 of flowers of benzoin. I proposed to determine with exact- 

 ness how much salt a given proportion of benzoin yields by 

 sublimation. For this purpose I distilled 1 Ib. of benzoin 

 in a retort, and, after having perfectly separated the 

 empyreumatic oil by lixiviation, I obtained between 9 and 

 12 drms. of flowers. This salt may be likewise obtained 

 by simply lixiviating the benzoin with water ; but the salt 

 thus obtained is less in quantity, and if the ley be made too 

 hot, the resin easily runs together, and the whole labour is 

 lost. The reason why simple lixiviation yields so little salt 

 is easily assigned. The resinous particles of the benzoin do 

 not transmit the water; the solution, therefore, takes 

 place only on the surface of the particles of the powdered 

 benzoin. 



I further boiled pounded chalk and benzoin in water, 

 and then filtered the decoction, but on its cooling obtained 

 no crystals ; but on pouring some drops of vitriolic acid into 

 this liquor, the salt of benzoin soon afterwards precipitated ; 

 for this salt, which is an acid, was united with the chalk. 

 The quantity of salt obtained, however, was not greater than 

 that obtained by lixiviation. I then fell upon the idea of 

 communicating to the water the power of acting upon the 



