6 ; 2 
streak or blemish in the grain. All these at- 
tentions are absolutely necessary to produce 
a tolerably regular grain ; and, after every 
tiling that can be done by the most experi- 
enced artists, still there is much uncertainty 
in the process. They are sometimes obliged 
to lay on the grain's several times, before they 
procure one sufficiently regular. The same 
proportions of materials do not always pro- 
duce the same effect, as it depends in some 
degree on their qualities ; and it is even 
materially altered by the weather. These 
difficulties are not to be surmounted but by 
a great deal of experience ; and those who 
are daily in the habit of practising the art, 
are frequently liable .to .the most unaccount- 
able accidents. Indeed it is much to be lament- 
ed, that so elegant and useful a process should 
be so extremely delicate and uncertain. 
It being necessary to hold the plate in a 
slanting direction, in order to drain off the 
superfluous fluid, there will naturally be a 
greater body of the liquid at the bottom than 
at the top of the plate. On this account, a 
grain laid in this way is always coarser at the 
side of the plate that was held lowermost. 
The most usual way is, to keep the coarsest 
side for the fore-ground, that being generally 
the part which has the deepest shadows. In 
large landscapes, sometimes various parts are 
laid with diiierent grains, according to the 
nature of the subject. 
The liner the grain is, the more nearly 
■does the impression resemble Indian ink, and 
the fitter it is for imitating drawings: hut 
very fine grains have several disadvantages ; 
for they are apt to come off before the aqua 
: fortis has lain on long- enough to produce the 
desired depth ; and as the plate is not cor- 
roded so deep, it sooner wears out in print- 
ing ; whereas coarser grains are tinner, the 
acid goes deeper, and the plate will throw off 
a great manv more impressions. The reason 
of all this is evident, when it is considered, 
that in the line grains the particles are small 
and near each other, and consequently the. 
aqua fortis, which acts laterally as well as 
downwards, soon undermines the particles, 
and causes them to come off. If left too 
long on the plate, the acid would eat away 
the grain entirely. 
On these accounts, therefore, the mode- 
rately coarse grains are more sought after, 
.and answer better the purpose of the pub- 
lisher, than the tine grains which were for- 
merly in use. 
Although there are considerable difficulties 
in laying properly the aquatint grain, yet 
the corroding of the copper, or biting in, so as 
to produce exactly the tint required, is still 
more precarious and uncertain. All engra- 
vers allow that no positive rules can be laid 
down, by which the success of this -process 
can he secured; nothing but a great deal of 
experience and attentive observation can 
enable the artist to do it with any degree of 
certainty. 
There are some hints, however, which may 
be of considerable importance to the person 
who wishes to attain the practice of this art. 
It is evident, that the longer the acid remains 
on the copper, the deeper it bites, and 
consequently the darker will be the shade in 
the impression. It may be of some use, 
therefore, to have several bits of copper laid 
with aquatint grounds, of the same kind to 
be used in the plate, and to let the aqua 
ENGRAVING. 
fortis remain for different lengths of time on 
each ; and then to examine the tints pro- 
duced in one, two, three, four minutes, or 
longer. Observations of this kind, frequently 
repeated, and with different degrees ot strength 
of the acid, will at length assist the judgment, 
in guessing at the tint which is produced in 
the plate. A magnifier is also useful to ex- 
amine the grain, and to. observe the depth to 
which it is bitten. It must be observed, that 
no proof of the plate can be obtained till the 
whole process is finished, it any part ap- 
pears to have been bitten too dark, it must be 
burnished down with a steel burnisher ; but 
this requires great delicacy and good ma- 
nagement not to make the shade streaky; 
and as the beauty and durability of the grain 
are always somewhat injured by it, it should 
be avoided as much as possble. 
Those parts which are not dark enough, 
must have a fresh grain laid over them, and 
be stopped round with varnish, and subjected 
again to the aqua fortis. This is called re- 
biting, and requires peculiar care and atten- 
tion. The plate must be very well cleaned 
out with turpentine before the grain is laid 
on, which should be pretty coarse, otherwise 
it will not lie upon the heights only, as is 
necessary in order to produce the same 
grain, if the new grain is different from 
the former, it will not be so clear nor so 
linn, but rotten. 
We have now given a general account of 
the process of engraving in aqua tinta, and we 
believe that no material circumstance has 
been omitted that can be communicated 
without seeing the operation : but after all it 
must be confessed, that no printed directions 
whatever can enable a person to practise it 
perfectly. Its success depends upon so many 
niceties, and attention to circumstances ap- 
parently trifling, that the person who attempts 
it must not be surprised if he does not suc- 
ceed at first. It is a species of engraving 
simple and expeditious, it every thing goes 
on well ; but it is very precarious, and the 
errors which arc made are rectified with great 
difficulty. 
It seems to he adapted chiefly for imitation 
of sketches, washed drawings, and slight 
subjects; but does not appear to be at all 
calculated to produce prints from finished 
pictures, as it is not susceptible of that ac- 
curacy in the balance of tints necessary for 
this purpose. Nor does it appear to be 
suitable tor book-plates, as it does not print a 
sufficient number of impressions. It is there- 
fore not to be put in competition with the 
other modes of engraving. If confined to 
those subjects for which it is calculated, it 
must be allowed to be extremely useful, as 
it is expeditious, and may be attained with 
much less trouble than any other mode of 
engraving. But even this circumstance is a 
source of mischief, as it occasions the pro- 
duction of a multitude of prints, that have no 
other effect than that of vitiating the public 
taste. See Etching. 
Engraving on wood . — Engraving on wood 
is a process exactly the reverse to engraving- 
on copper. In the latter, the strokes to be 
printed are sunk, or cut into the copper, arid 
a rolling-press is used for printing it; but in 
engraving on wood, all the wood is cut away, 
except the lines to be printed, which are left 
standing up like types, and the mode of print- 
ing is the same as that used in letter-press. 
4 
\ 
The wood used for this purpose is box''-] 
wood, which is planed quite smooth. The 
design is then drawn upon the wood itself 
with black lead ; and all the wood is cut away 
with gravers and other proper tools, bxcept 
the lines that are drawn. Or sometimes the 
design is drawn upon paper, and pasted upon 
the wood, which is cut as belore. The art isj 
of considerable difficulty, and there are very! 
few who practise it. It is, however, useful! 
for bocks, as the printing of it is cheapen 
than that of copper-plates. It cannot bel 
applied equally well to all the purposes to ! : 
which copper-plate engraving is applicable. 1 
In engraving on precious stones, they! 
use either the diamond, or emery. The 
diamond, which is the hardest of ail stones,! 
is only cut by itself, or with its own matter J 
The first: thing to be done in this branch off 
engraving, is to cement two rough diamonds! 
to the ends of two sticks large enough to hold) 
them steady in the hand, and to rub or grinds 
them against each other till they are brought] 
to the desired form. The dust, or powder,; 
that is rubbed off, serves afterwards to polisll 
them, which is performed with a kind of mill 
that turns a wheel of soit iron. The diamonci 
is fixed in a brass dish, and thus applied tew 
the wheel, is covered with diamond-dust] 
mixed up with oil of olives; and when the] 
diamond is to be cut facet-wise, they apply] 
lirst one face, then another, to the" wheel] 
Rubies, sapphires, and topazes, are cut ami 
formed the same way on a copper wheel, ami 
polished with tripoli diluted in water. As toj 
agates, amethysts, emeralds, hyacinths, gral 
nites, rubies, and others of the softer stones] 
they are cut on a leaden wheel, moistened 
with emery and water, and polished w all 
tripoli, on a pewter wheel. Lapis-lazuli] 
opal, &c. are polished on a wooden wheel] 
To fashion and engrave vases of agate] 
crystal, lapis-lazuli, or the like, they make! 
use of a kind of lathe, like that used by 
pewterers to hold the vessels, which are to he 
wrought with proper tools: that of the eni 
graver generally holds the tools, which are 
turned b v a wheel ; and the vessel is held td 
them to be cut and engraved, either in relievq 
or otherwise ; the tools being moistened, 
from time to time, with diamond-dust and 
oil, or at least emery and water. Tq 
engrave figures or devices on any of the>] 
stones, when polished, such as medals, seals] 
&c. they use a little iron wheel, the ends o| 
whose axis are received within two pieces oj 
iron, placed upright, as in the turner’s lathe] 
and to be brought closer, or set further apart] 
at pleasure : at one end of the axis are fitted 
the proper tools, being kept tight by a screw] 
lastly, the wheel is turned by the toot, and 
the stone applied by the hand to the tool] 
and is shifted and conducted as occasio] 
requires. 
The tools are generally of iron, and soma 
times of brass: their form is various ; but i 
generally bears some resemblance to chisel] 
gouges, "&c. Some have small round head] 
like buttons; others like ferules, to take thj 
pieces out ; and others flat, &c. When tl] 
stone lias been engraved, it is polished of 
wheels of hair-brushes and tripoli. 
Engraving on steel is chiefly employ® 
in cutting seals, punches, matrices, and Jy] 
proper for striking coins, medals, and corn] 
ers. The method of engraving with the in 
struments, Ike. is the same for coins as f] 
