PRACTICAL PAPERS—SUGAR-BEET AND BEET SUGAR. 241 
Concentration .—The purified, filtered, and decolorized juice 
is concentrated by the action of heat, which causes it to lose its 
excess of water, and brings it gradually to the density necesr 
sary for crystallization. This operation is divided into two 
parts : concentration, properly so called, and cooking or bak¬ 
ing. It is well known that the boiling point of a liquid in a 
vacnum is at very much lower temperature than it is when ex¬ 
posed to atmospheric pressure. Upon this principle the appli¬ 
cation of the vacuum concentrating and cooking the juice 
rests. 
The introduction of vacuum boilers is almost the only im¬ 
provement, in reality, which has been made in the manufacture 
of sugar for thirty years, for the elements of all the other im¬ 
provements which have been made were contained in the old 
processes. With the apparatus now used, it is impossible to 
caramelize the sirup, and the cooking or baking may be pushed 
to crystallization—an operation which is called baking in 
grains, and which is described at length in the accompanying 
report; finally, the heat is not sufficient to cause the saccha- 
rate alkalies, which have been left in the juice, to produce any 
reaction of importance. The machines for concentration 
which have produced the best results are manufactured by 
M. Cail & Co., and are known as machines of triple effect. 
Crystallization .—This is usually done in vats. The sirup is 
exposed to a temperature of from thirty to thirty-five degrees' 
centigrade, which is maintained as uniform as possible till the 
crystallization is complete. 
The turbine, by means of which the sirup is separated from 
the crysallized sugar, is a great improvement over the ordinary 
and older methods. By the use of this machine the purifica¬ 
tion of the crystals of the sugar is reduced to an almost instan¬ 
taneous mechanical operation. 
The other operations and processes connected with the man¬ 
ufacture of sugar, some of which are recent and some of older 
date, will be described at length in the accompanying report. 
At the present time the machinery for a complete and well- 
arranged sugar factory consists of washing machines, rasps, 
Ag. Tr.— 16 . 
