ing. After
it has been fanned (see p. xxi) until it has thickened sufficiently not
to stick to the finger when touched, but before it is quite dry, it can
be worked upon with the point. If not dry enough, which will manifest
itself readily as soon as you have drawn the first line, fan again. If
it were allowed to dry absolutely, it would chip off under the needle.
There is a liquid ground, made by Mr. Louis Delnoce of the American Bank
Note Company, New York, which--so Mr. Jas. D. Smillie informs me--is
used for retouches by the engravers of the company, is applied with the
brush, is a very quick dryer, tough, and resists acid perfectly. Mr.
Delnoce sells it in ounce bottles at seventy-five cents each.

[5] (p. 12.) The roller for revarnishing, spoken of by M. Lalanne, and
also recommended by Mr. Hamerton, cannot be bought in this country.
Nor--with all due deference to the great experience of M. Lalanne--is
such a large and expensive roller necessary. The rollers used by our
most experienced etchers--Mr. Jas. D. Smillie, for instance--are little
cylinders of India-rubber, about one inch in diameter and one and
one-half inches long. They cost from 50 cents to $2 each. _But these
rollers cannot be used with etching-paste._ The oil of lavender in the
paste attacks the rubber and destroys it. As to the manner of using the
India-rubber roller see Note 12.

[6] (p. 20.) The use of bordering wax is not advisable. But as some
etchers still employ it, I add a recipe for making it, which was kindly
communicated to me by Mr. Peter Moran of Philadelphia:--

3 lbs. Burgundy pitch.
1 lb. yellow beeswax.
1 gill sweet oil.

Melt together and then form into strips.

[7] (p. 21.) Etching is the most individual of the reproductive arts (or
rather of the _multiplying_ arts, the German _vervielfaeltigende
Kuenste_), even in its technical processes. Therefore nearly every etcher
has his own ways of doing, and few agree on all points. Many etchers do
not think it necessary to weaken the acid as described in the text. But
be sure to let it _cool_ after it has been mixed with water, before you
immerse your plate!

[8] (p. 22.) It would take altogether too long to wait for the _perfect_
drying of the asphaltum varnish, nor is it necessary. Fan it, as
described in Note 4, and as soon as it ceases to stick you can again
immerse your plate.

[9] (p. 25.) I have never been able to notice this turning dark of the
lines, although I ha