74 SUGAR 



by making new crystals but by building up the crystals 

 already existing in the mass. This has been called 

 " crystallization in motion." The same process may 

 be applied to the so-called first-product, which has been 

 boiled not only from pure juice but also, at the end of 

 the boiling, with an admixture of second syrup. This 

 addition makes the masse-cuite, at the end of the opera- 

 tion, more viscous than it otherwise would be ; but the 

 process of subsequent stirring helps the viscous syrup 

 to deposit more sugar on the grains, and the result is 

 a good imitation of a genuine first product. 



The scientific explanation of this method of adding 

 a less pure syrup to the pan nearly full of a first product 

 masse-cuite is worth a moment's attention. As long 

 as the boiling, and, therefore, evaporation, of the 

 crystallized mass in the pan continues, the " mother 

 liquor " in which it moves should continue to deposit 

 fresh sugar on the crystals. But the time comes when 

 the mass is so dense that it is impossible to continue 

 the crystallization, That is the time to introduce some 

 second syrup, that is, the "mother liquor" from the 

 previous masse-cuite, which has been thrown off in the 

 centrifugal machine. This at once makes the dense 

 mass of sugar in the pan more fluid, and enables the 

 deposition of sugar on the crystals to begin again. This 

 further crystallization comes not only from " the mother 

 liquor " in the pan but also from that brought in from 

 the centrifugal machines. The subsequent stirring in 

 the apparatus for promoting crystallization-in-motion 

 adds still more sugar to the grains of crystal, and thus 

 the second syrup is induced to yield a considerable 

 quantity of its sugar in the form of good first product. 

 It looks as if this could only be carried on up to a certain 

 point ; but that difficulty can be got over by doing 

 it in two stages. A small quantity of juice is boiled 



