hid or covered by thefc tinges, but combines with
them; and, for the fame reafon, if the ftones be of
any of the pure colours, the refult will be a com-
pound of fuch colour and that of the tinge.
RETCHING and ENGRAVING.
J^TCHING is a method of working on copper,
~* wherein the lines or ftrokes, inftead of being
cut with a graver, are eaten with aquafortis.
This art being executed with greater eafe and
freedom than engraving, represents curious fubjefts
better, and more agreeable to nature, as landfkapes,
ruins, and fmall, faint, or remote objefts, build-
The principal materials for this art are the plate,
hard and foft gound, (the firib for winter, and the
other for fummer) a dabber, turpentine varnifh, lamp
black, foft wax, and aquafortis.
The tools are. an oil rubber, aburnifher, a fcraper,
a hand vice, etching boards, etching needles, an oil
fcone, and a parallel ruler.
Directions for laying the ground.—Having pro-
vided yourfelf with a plate of the fize of the print,
or drawing you intend to copy, rub it well with an
oil rubber, made of fwan-fkin flannel, till all the
marks of the charcoal ufed in polifhing it, entirely
difappear ; then, wiping off the dirty oil with a linen
rag, dip your finger in fome clean oil, and touch
it over every part of the plate ; after which, with
your burniflier polifh the plate, till you can fee your
face in it ; and in cafe any fand holes, or flaws ap-