Page 272 - My FlipBook

270 THE OPERATION OF FILLING CAVITIES.

If mats are required, the foil may be folded twiee or three times and
then folded lengthwise upon itself until mats of any thickness are pro-
duced, as shown in Fig. 223.
When non-cohesive cylinders are desired, it is better for the operator
to make them rather than depend upon the ready-made ones as prepared
by the manufacturer, since these are usually loosely rolled and more or
less cohesive. The tape is quickly made into the cylinder by rolling it
Fig. 222. Fig. 223.

iapcK of giili-i lull. Mats of gold foil.
upon a five-sided broach to the desired size. The depth of the cavity
is a guide to the width of the tape, and the width of the tape determines
the length of the cylinder. These should be somewhat longer than the
depth of the cavity. The manner of introducing and condensing will
be described later when special cases are under consideration.
The roll, or " rope " as it was formerly called, is made in the following
way A leaf or half leaf or a third of a leaf of foil is rolled between the
:
Fifi. 224.

JJevice fur rolling gold foil.
thumb and finger until a roll of moderate density is obtained. As foil
is contaminated by contact with the moisture and surface impurities of
the hands, it is better to avoid such contact as much as possible. This
can be completely attained by rolling it upon the little device shown in
Fig. 224. Any operator can make one of these by taking two pieces of
thin board, such for instance as the lid of a cigar box, and fastening
to the two pieces with glue a piece of white kid about eight inches in