As to the steel-cut appearance of the lines, Dr. Brinton says: "The
lines on the Lenape Stone are obviously cut with a steel instrument,
making clean incisions, deepest in the centre and tapering to points,
quite different from the scratch of a flint point"; and Dr. M. E.
Wadsworth thinks that "the depth and regularity of the carvings
indicate that they were made with some dulled steel tool like an
awl." On the other hand Mr. J. E. Iddings does not know whether it is
possible thus to distinguish the work of steel and flint instruments,
and a series of experiments with the microscope and steel and flint
points has induced the writer to believe that lines cut on a similar
stone by "a dulled steel instrument" and a flint arrow-point cannot be
distinguished after both have been washed and scrubbed.
The appearance of such lines would of course depend much upon the
sharpness of the flint or steel point, the kind of stone used, and
whether the lines were cut by one or by a series of strokes. The single
scratch of a scissors point on a shale tablet of similar hardness
makes an incision in shape like the letter V; that of either an awl or
flint arrow-head one like the letter U; while any line made by either
instrument and consisting of a series of strokes will have its bottom
furrowed by parallel grooves, as in the case of the large lines on the
Lenape Stone.
The fresh flint-cut grooves, however, when separately examined with the
microscope, exhibit many faint scratches running along the furrow, not
so conspicuous in the steel incisions, yet a few applications of soap,
water, and a scrubbing-brush efface these scratches in both cases,
and render the surface of the grooves indistinguishably alike and in
appearance similar to the now polished incisions upon the Lenape Stone.
In other respects the scratch of the arrow-head can be made of equal
depth, clearness, and regularity, the flint point, if held carefully,
not appearing to tear the edges of the incision more than the awl.
Moreover, we can cause the flint-cut line to "taper to a point" or not,
as we choose.