all round
this line just as an indication, merely as a starting point from
which to work more deeply all over, until I arrive at a point when
the calipers, No. 34, test the thicknesses roughly--which is by the
way. For I have first to cut three cross channels, at the upper,
middle, and lower nodal points, fig. 11, at such a depth that I
caliper good three-sixteenths of an inch at the centre of middle
groove, one-eighth of an inch upper and lower, falling away very
little to all edges for the present. And I draw a distinct pencil
mark through each groove, so that I must be a poor workman indeed if
I go through the wood through these bars, as I have known some
novices to do, or cannot gauge pretty well all over by their aid
before using the calipers.

[Illustration: PLATE XI.]

But you who, when beginning to cut out back or belly, having no sort
of experience whatever, must use every care possible, and keep
calipers No. 3 (double) going constantly, as, with their aid, you
will at once see by the outside half the thickness registered at the
inner; then you can pare away with gouges, small and large, and with
spoke shaves, Nos. 48 and 53, until you get a fairly sloping and
somewhat level surface from bare three-sixteenths of an inch in
centre to full three-thirty-seconds of an inch all round by the
edges, as shown by calipers.

And thus I come to the first rough thicknesses of the back; and I
damp the surface all over as I did the outside, and dry it
carefully; for you will understand the necessity for this
carefulness, there being some fear of slight warping from the true
flatness now the wood is thin all over, if quick, artificial heat be
adopted to draw the moisture.

Whilst this natural process is going on, you must take the large
calipers and open them at three-sixteenths of an inch. Then hold the
plate in the extended left hand by middle bout, inside upwards,
calipers and a long lead pencil _together_ in the other; and,
beginning at the centre of the plate, draw the calipers carefully
from this starting-point all over the rough surface, gauging with
your eye for the present any irregularities of said surface; for I
want you to mark every part where the points stick, first within a
radius of three inches, gradually extending your field of
operations, slightly tightening the calipers as you get farther away
from your centre, until the edges are finally reached, when you use
the double calipers, No. 3, to ascerta