te steam of the engine; then be limed and scummed if necessary,
and concentrated to fifteen or sixteen of the prese sirop; then
purified by filtration through animal charcoal, if white sugar was
wanted, or by rest for other qualities; and finally concentrated in
vacuum pans of great power, such pans as Mr. Thomas A. Morgan, of
Louisiana, now uses, and which, I am informed, are only made in
America.

The superiority of the vacuum pan is not universally admitted, and we
are told that in France it is superseded by open pans, similar to
those called in America "Mape's Evaporators." However this may be, I
cannot help believing that the vacuum pan has many decided advantages
over all others. One is manifest; the sugar may be grained in the pan,
and the granulation is completely under the control of the operator.
He may accelerate or retard it at pleasure; he may carry it so far
that sugar will not run from the pan, and will have to be taken out of
it; he may so conduct the operation as to increase, almost at will,
the size and hardness of the crystals. This last is an indispensable
requisite if the practice of draining sugar in pneumatic pans should
be adopted.

The atmospheric pressure is made too powerful for sugars boiled in any
other manner; it breaks and destroys the crystals, and in a very few
days sets the sugar to fermenting.

The pneumatic draining of sugar has many things to recommend it--the
usual loss by drainage is avoided, sugar is got ready for market day
by day, as it is made, and it may be bleached by pouring white syrup
over it and forcing it through the mass. It is said that the process
is attended with considerable loss in weight, but as all that drains
from the pan may be boiled over once or twice, it is not easy to
conceive how the loss can occur.

Cane juice contains many ingredients besides sugar, the principal of
which are albumen, gluten, gum, starch, resin, wax, coloring matter,
and certain salts, all of which, either collectively or individually,
have the power of preventing granulation, as may be proved by their
addition to a syrup of pure sugar, which will then defy all attempts
to make it crystallise. If, therefore, we want to make good sugar, we
must endeavour to free our cane juice as much as possible from those
substances.

Now, cane juice is no more the sap of the cane, than apple juice is
that of the apple tree; it is the natural product of the cane, and, in
all probability, would co