176 PREPARATION OF FARINA AND SUGAR. [Til. 



nufacturer might at first test his liquors and sugars with all 

 possible care, to insure the removal of every trace of lead, but 

 can he be sure that the same nicety will be observed when he 

 transfers this operation to workmen ? If a chemist were em- 

 ployed, might not his tests sometimes deceive him ? Now, it 

 may be shown that a very minute dose of lead, frequently 

 repeated, will produce deleterious effects on the system ; and 

 yet such traces are apt to elude the vigilance of even an ex- 

 perienced chemist, when he is called upon to repeat his tests 

 day after day. In the patent referred to (Lond. Journ. Sept. 

 1850), the collection of sulphite of lead as a pigment is too 

 trivial to notice further. 



Acetate of alumina may be safely used in defecating sac- 

 charine solutions (see Oxland's patent, Lond. Journ. Sept. 

 1850), but whether efficient or not, is to be tried. It is probable 

 that it will answer a good purpose in part, from the ac- 

 knowledged effect of aluminous solutions. In the above 

 patent, the remainder of alumina is thrown down by a solution 

 of tannin. The two substances are stated to be used either 

 before or after neutralization by lime in the case of cane juice 

 or beet-root juice. The acetate of alumina is easily made by 

 precipitating sulphate of alumina by alkali, washing thoroughly 

 and dissolving the moist precipitate in vinegar. It is stated 

 that, on trial, 4i]b of alumina were sufficient for one ton of 

 sugar. 



Another patented process (Rep. Pat. Inv. July, 1850) for 

 clarifying cane juice and sugar solutions, is the use of sul- 

 phate of alumina with chalk and silex. The process seems to 

 be not well digested, and there is a liability of leaving some 

 soluble sulphate in solution, which tends to injure sugar upon 

 evaporation. 



Extraction of Sugar. — Melsen's novel process (Gard. Chron. 

 1849) for extracting sugar from cane juice, consists in the use 

 of sulphurous acid combined with lime, forming a bisalt. Its 

 presence arrests the action of the air, and thus prevents the 

 development of any ferment. In accomplishing so much, it 

 obviates all the difficulties heretofore experienced, in the 



