ution of sulphate of copper. A piece of
copper attached to the wire in connection with the copper end of the
battery must also be inserted into the copper solution facing ihe
gutta percha, but not touching it; this not only acts as a conductor
to the electricity, but also maintains the solution of copper of a
permanent strength.

In a short time the copper will be found to creep over the whole
surface of the gutta percha, and in about twenty-four hours a thick
deposit of copper will be obtained, which may then be detached from
the mould. The accuracy with which a leaf may thus be cast is truly
surprising.

2334. Leaf Printing.

After warming the leaf between the hands apply printing ink, by means
of a small leather ball containing cotton, or some soft substance, or
with the end of the finger. The leather ball (and the finger, when
used for that purpose), after the ink is applied to it, should be
pressed several times on a piece of leather, or some smooth surface,
before each application to the leaf, that the ink may be smoothly and
evenly applied. After the under surface of the leaf has been
sufficiently inked, apply it to the paper where you wish the
impression to be; and, after covering it with a slip of paper, use the
hand or roller to press upon it.

2335. Directions for Taking Leaf Impressions.

Hold oiled paper in the smoke of a lamp or of pitch, until it becomes
coated with the smoke; to this paper apply the leaf of which you wish
an impression, having previously warmed it between your hands, that it
may he pliable. Place the lower surface of the leaf upon the blackened
surface of the oil-paper, that the numerous veins, which are so
prominent on this side, may receive from the paper a portion of the
smoke. Lay a paper over the leaf, and then press it gently upon the
smoked paper with the fingers, or with a small roller covered with
woollen cloth, or some similarly soft material, so that every part of
the leaf may come in contact with the sooted oil-paper. A coating of
the smoke will adhere to the leaf. Then remove the leaf carefully, and
place the blackened surface on a sheet of white paper, or in a book
prepared for the purpose, covering the leaf with a clean slip of
paper, and pressing upon it with the fingers, or roller, as before.

Thus may be obtained the impression of a leaf, showing the perfect
outlines, together with an ac