92 SUPPLEMENT. 
These operations require the greatest exactness, for 
If we do not boil enough, the sugar contained in the solution will 
not crystallize when cold; or, 
If we boil too much, the molasses will become so thick when it cools, 
as to impair the crystallizing of the sugar, and cannot be separated 
from it. 
But how shall we know when to stop the boiling ? 
By the heat of the boiling liquid, as marked by the thermometer. 
Pure water boils at 212 degrees of Fahrenheit’s thermometer. You 
cannot make it hotter without changing it to steam. 
The Sorgho juice, being a solution of about fourteen per cent. of 
sugar and molasses, &c., in water, becomes three degrees hotter before 
boiling, and boils at 215° Fahrenheit. As the water evaporates, a 
greater heat is required to keep the concentrated juice at a boil; in 
other words, the juice grows hotter and hotter. When it reaches the 
heat marked on the thermometer 238° Fahrenheit, there is just enough 
water left to enable the sugar to separate from the molasses when cold. 
6. We now pour the concentrated juice into a mould, a keg, a bar- 
rel, or other deep vessel, with a plug in the bottom, and allow it to cool. 
- 7. When quite cold (say in twenty-four hours), we remove the plug. 
The liquid portion, being molasses with a little sugar and water, 
gradually drains out, leaving the sugar dry in from four to ten days. 
It is also important to remember 
That the juice begins to ferment almost as soon as it leaves the 
cane, and therefore, should be neutralized, clarified, and boiled without 
gelay. A very few hours’ delay will spoil it. 
A long continued exposure to heat gradually converts crystallizable 
sugar into uncrystallizable molasses, therefore, the evaporation should 
be as rapid as possible. 
A concentrated solution of sugar and molasses is very liable to burn, 
and should, therefore, be carefully watched, and exposed to a more and 
more moderate fire as the evaporation advances. 
The use of a saccharometer is to indicate the relative weight or 
density of a liquid as compared with water. This density depends 
upon the amount of sugar, or other heavy substances held in solution. 
