bring more fuel into a given space,
thus making it capable of giving out an intenser heat; at the same time
increasing its hardness and toughness, and rendering it easier and more
economical of transportation. 2. _Drying_ by artificial heat or reducing
the amount of water from 20 or 25 _per cent._ to half that quantity or
less. This exalts the heating power in no inconsiderable degree. 3.
_Charring._ Peat-charcoal is as much better than peat, for use where
intense heat is required, as wood charcoal is better than wood. 4.
_Purifying from useless matters._ Separation of earthy admixtures which
are incombustible and hinder draught.

A.--_Condensation by Pressure._

_Pressing Wet Peat._--The condensation of peat was first attempted by
subjecting the fresh, wet material, to severe pressure. As long ago as
the year 1821, Pernitzsch, in Saxony, prepared peat by this method, and
shortly afterwards Lord Willoughby d'Eresby, in Scotland, and others,
adopted the same principle. Simple pressure will, indeed, bring fresh
peat at once into much smaller bulk; but, if the peat be fibrous and
light, and for this reason require condensation, it is also elastic,
and, when the pressure is relieved, it acquires again much of its
original volume.

Furthermore, although pressure will squeeze out much water from a
saturated well-ripened peat, the complete drying of the pressed blocks
usually requires as much or more time than that of the unpressed
material, on account of the closeness of texture of the surface produced
by the pressure.

The advantages of subjecting fresh peat to pressure in the ordinary
presses, it is found, are more than offset by the expense of the
operation, and it is therefore unnecessary to give the subject further
attention.

Fresh peat appears however to have been advantageously pressed by other
mechanical means. Two methods require notice.

_Mannhardt's Method_, invented about the year 1858, has been practically
applied on the large scale at _Schleissheim_, Bavaria. Mannhardt's
machine consists of two colossal iron rolls, each of 15 feet diameter,
and 6-1/2 feet length, geared into each other so as to revolve
horizontally in opposite directions and with equal velocity. These rolls
are hollow, their circumference consists of stout iron plate perforated
with numerous small holes, and is supported by iron bars which connect
the ends of the roll, having intervals between them of about one inch.
Each roll is covere