472 ON THE JUICE OF THE SUGAR-CANE. 
result the brown colour of the syrup, and for its ulterior consequence, 
the production of a dark, dirty, and clammy sugar. 
Without going further into such well-known details as this action of 
the lime on the juices containing a certain quantity of levulose, I may 
say that the difficulties of sugar manufacture in damp localities, and the 
inferior quality of their production until the introduction of the vacuum- 
pan system, must be chiefly, if not entirely attributed to the large pro- 
portion of liquid sugar nominally contained in the leaves grown in 
these localities, and nearly always cut in lull vegetation. When the 
juice contains only traces of this substance, which happens when the 
canes are grown in dry and airy localities, its manipulation becomes 
much more easy ; but even then the use of lime cannot be exaggerated 
without very manifestly injuring the quality of the sugar. 
The speciality of lime in the modern manufacture of sugar must 
"be limited to the purpose of neutralising gradually and moderately the 
acidity of the juice. When used in too small a quantity, this alkali 
will not oppose a sufficient obstacle to the glucose transformation of 
crystallizable sugar under the influence of that azotised matter which is 
not coagulable by heat, and the syrups will then be highly charged 
with levulose ; used in such a manner as to keep up in this liquid a 
slight alkaline reaction, cane sugar will hardly ever become interverted, 
though it will assume a shade of colour which will cause it to occupy a 
much lower rank in the sugar market. But since the most sought after 
and most remunerative qualities or shades of sugar can only be produced 
by means of a juice kept slightly acid, the attention of the manufacturer 
should be directed in such a manner as to produce these shades of 
quality with the least possible glucose transformation ; that is, for a 
given type never to exceed the degree of acidity which such type re- 
quires. 
But it is particularly after the separation of the scum that the 
greatest attention must be paid to the acidity of the juice, for the tempe- 
rature of the liquid then rises rapidly, and the intervention of crystal- 
lizable sugar then most easily takes place. This acidity increases in the 
ratio of the proportion of incoagulable albuminoid matters which thus 
become the indirect though active cause of the formation of glucose. 
(To be continued.) 
