EXTRACTION OF SUGAR. 393 



so far as the value of the refuse for feeding purposes is con- 

 cerned. A comparison of the composition of the juices 

 obtained by means of a powerful hydraulic press and by 

 Roberts's maceration (or the dialytic mode), may aid in 

 understanding this question, of which I shall have to treat 

 somewhat more in detail hereafter : — 



I. 



Beet-juice procured by the aid of a hydraulic press con- 

 tains : — 



Per cent. 



Sugar 12.410 



Potassa and soda compounds . 

 Lime and magnesia 

 Nitrogenous substance 



Non-nitrogenous organic substances 



0.458 

 0.187 

 1.418 

 1.048 



II. 



Beet-juice procured by Roberts's diffusion apparatus with 

 an addition of fifteen per cent of water, contains : — 



, Per cent. 



Sugar 11.580 



Potassa and soda compounds 0.441 



Lime and magnesia 1.191 



Nitrogenous substance ...... 0.791 



Non-nitrogenous organic substances . . . 0.983 



YIELD OF SUGAR. 



According to the mode of operation pursued, more or less 

 sugar will be left with the cellular refuse mass. The residue 

 of the hydraulic press contains from three and three-fifths 

 to four and four-fifths per cent of sugar, or seventy-six hun- 

 dredths per cent of the amount in the original sugar-beet; 

 while Roberts's mode leaves but one-tenth to two-tenths per 

 cent of sugar. Between these figures lie the quantities of 

 sugar left by the application of other modes of operation. 

 "With the removal of the juice begins, consequently, the loss 

 of sugar, which amounts, during the whole operation for its 

 final separation, to about three and a half per cent under a 

 good management of existing methods. To set down losses 

 which occur in a branch of manufacture where peculiar skill 

 so decidedly bears upon the final results, is no doubt quite 

 arbitrary; but it is of interest to notice where they usually 



