ENAMELLING. 
about one-tenth of an inch. He afterwards 
takes up the enamel with an iron spatula as 
equally as possible. As the enamel here 
spoken off is transparent, it is usual to orna- 
ment the gold with rose work, or other 
kinds of work, calculated to produce a 
good dFect through the enamel. 
The thickness of this first layer depends 
entirely upon its colour : delicate colours in 
general require that it should have no great 
thickness. 
The moist enamel being thus placed, is 
dried by applying a very clean half-worn 
linen cloth to it, which must be very care- 
fully done to avoid removing the enamel by 
the action of wiping. 
In this state the piece is ready for the 
fire. If it be enamelled on both sides, it is 
placed upon a tile, or' iron plate, hollowed 
out in such a manner that the uncovered 
edges of the piece alone are in contact 
with the support. But if it be enamelled 
on one side only, it is simply laid upon the 
plate, or upon a tile. Two things, however, 
require to be attended to. 1. If the work 
be very small, or not capable of being ena- 
melled on the opposite side, the iron plate 
must be perfectly flat, in order that the work 
may not bend when softened by heat. 2 . If 
the work be of considerable size, it is al- 
ways counter-enamelled, if possible ; that is 
to say, an enamel is applied on the back 
surface, in order to counteract the effect 
which the other coating of glass might pro- 
duce on the soft metal when it came to con- 
tract by cooling. 
The enameller’s furnace is square, and 
built of bricks bedded in an earth proper for 
the purpose. It may be considered as con- 
sisting of two parts, the lower part which 
receives a muffle resting on the floor of the 
furnace, and open on both sides. 
The upper part of the furnace consists of 
a fire place, rather larger and longer than 
the dimensions of the muffle. The fire 
place contains the muffle, and must sur- 
round it on all sides, except at the bottom. 
The charcoal is put in at a door above the 
muffle, which is closed as soon as the fire is 
lighted. A chimney proceeds from the 
summit of the furnace with a moderate 
aperture, which may be closed at the 
pleasure of the artist, by applying a cast iron 
plate to it. This furnace differs from that 
of the assayer, in the circumstance that it is 
supplied with air through the muffle itself : 
for if the draught were beneath the muffle, 
the heat would be too strong, and could not 
be stopped when requisite. 
As soon as the fire is lighted, and the 
muffle has acquired the requisite degree of 
ignition, the charcoal is disposed towards 
the lower part of the muffle in such a man- 
ner as that it shall not fall upon the work, 
which is then conveyed into the muffle 
with the greatest care upon the plate of 
iron or earthern-ware, which is taken out by 
long spring pincers. The work is placed as 
near as possible at the farther extremity of 
the muffle ; and as soon as the artist per- 
ceives a commencement of fusion, he turns 
it round with great delicacy, in order that 
the fusion may be very uniform. And as 
soon as he perceives that the fusion has en- 
tirely taken place, he instantly removes it 
out of the furnace : for the fusion of gold 
happens so very near to that of the enamel, 
that the neglect of a few seconds might be 
attended with considerable loss. 
When the work is cooled, a second coat 
of enamel is applied in the same manner as 
the first, if necessary. This and the same 
cautious management of the fire are to be 
repeated for every additional coat of ena- 
mel the nature of the work may demand. 
As soon as the number of coatings are 
sufficient, it becomes necessary to give an 
even surface to the enamel, which though 
polished by the fire, is nevertheless irregu- 
lar. This is done with a "fine grained Lan- 
cashire file, and water. As the file wears 
smooth, sand is used. Much precaution 
and address are required in this part of the 
work, not only because it is easy to make 
the enamel separate in splinters from the 
metal, but likewise because the colour 
would not be uniform if it were to be 
ground thinner at one part than at another. 
The deep scratches of the file are in the 
next place taken out by rubbing the sur- 
face with a piece of deal wood and fine 
sand and water. A polish is then given 
by a second ignition. This polish, however, 
is frequently insufficient, and not as per- 
fectly uniform as the delicacy of the work 
may require. 
The substance used by the enamellers as 
a polishing material is known by the name 
of rotten-stone, which is prepared by 
pounding, washing, decanting off the turbid 
w'ater, suffering the fine suspended parti- 
cles to subside from this water, and lastly 
levigating it upon a glass plate. 
The work is then cemented to a square 
piece of wood, with a mixture of resin and 
brickdust, and by this means fixed in a 
vice. 
The first operation of polishing is made 
