The telegraph manual: a complete history and description of the semaphoric, electric and magnetic telegraphs of Europe, Asia, Africa, and America, ancient and modern.

INJECTION OF POLES WITH SULPHATE OF COPPER. 691
Fig. 1.
ing according to the number of posts to be prepared at one
time, as seen in fig. 1.
Against the two sides of this scaffold, the poles a a are
leaned at such an inclination, that their upper part may be
within easy reach on scaffold floor c. The small or upper end
of the pole rests in a little ditch of the earth, d d, sloped to fit
the angle of the pole. This ditch may be a trough made of
plank or iron. This trough empties the liquid coming through
the posts into casks.
On the side, and above the scaffold, is a framework with a
pulley and a bucket, by means of which is drawn up the solution from a reservoir, b, situated on the earth.
The posts are drawn up with their bark on. The summit of
the tree, or the top end of the pole, is placed at the ground,
and the large end on the scaffold, so as to give the movement
of the liquid the natural course with the sap. A thin slice is
~sawed off the butt or foot end of the pole, to give a free egress
for the liquid. The butt end is given the form of a frustum of
a cone, to which is fitted a lead receiver made of two firustums of
cones united. The axis of the upper cone is always vertical.
These caps or receivers made of lead, about four fifths of an inch
thick, must fit perfectly tight to the pole, so that the liquid can
not leak out and waste; and in order to accomplish this, the
butt end of the post is surrounded with soft clay before the
liquid is put in the receivers. This capping of the post is generally done before they are raised upon the scaffold. As soon
as the posts are placed as indicated in the figure, the injection
commences.
The lead caps are filled with a solution of the sulphate of
copper taken from the reservoir.
This liquid must contain one pound of the sulphate to one
hundred pounds of water. In order to make the solution easily,,