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ENA 
E N A 
EMPLEURUM, a genus of the monoe- 
eia tetrandria class and order. The male 
calyx is four-cleft ; corolla none; fern, calyx, 
four-cleft inferior ; corolla none; stigma cy- 
1 iiidric ; caps, opening at the side ; seed one, 
arilled. There is one species, a shrub of the 
Cape. 
EMPYEMA, in medicine, a disorder 
in which purulent matter is contained in the 
thorax or breast, after an inflammation and 
suppuration of the lungs and pleura, which, 
if it is not timely discharged, not only ob- 
structs respiration, but also returning into 
the blood occasions a continual hectic, with a 
consumption of the whole body, and other 
bad symptoms. See Medicine. 
empyreuma, among chemists and 
physicians, the fiery taste or offensive smell 
which brandies, and some other bodies pre- 
pared by fire, are impregnated with. 
EMI) LG ENT or Renal Arteries, 
those which supply the kidneys with blood; 
being sometimes single, sometimes double on 
each side. 
EMULSION, in pharmacy, a soft liquid 
substance, of a colour and consistence re- 
sembling m:lk. See Pharmacy. 
EMUNCTORY, in anatomy, a general 
term for all those parts which serve to carry 
olt the excrementitious parts of the blood and 
other humours of the body. Such more es- 
pecially are the kidneys, bladder, Ac. 
ENALLAGE, in grammar, is when one 
word is substituted for another of the same 
part of speech ; a substantive for an adjective, 
as exercitus victor for victoriosus, seel us for 
scelestus; a primitive for a derivative, as Dar- 
dana arma for Dardania, laticem lyajum for 
lyaeeium ; an active ior a passive, as nox hu- 
mida coelo praecipitat, for praecipitatur, &c. 
Enallage, in rhetoric, is a figure by 
which the discourse is changed and reversed 
contrary to all the rules of the language; but 
this is not done altogether at pleasure, or 
without reason. 
ENALURON, according to Guillim, is a 
bordure charged with birds; though others 
will have it to signify, in orle, or form of a 
bordure. 
ENAMEL, a kind of coloured glass, used 
in enamelling and painting in enamel. Ena- 
mels have for their basis a pure crystal-glass 
or frit, ground up with a fine calx of lead and 
tin prepared for the purpose, with the addi- 
tion usually of white salt of tartar. These 
ingredients baked together are the matter of 
all enamels, which are made by adding co- 
lours of different kinds in powder to this mat- 
ter, and melting or incorporating them toge- 
ther in a furnace. 
For white enamel, Neri De Arte Vitriar. 
directs only manganese to be added to the 
matter which constitutes the basis; for azure, 
zaffer mixed with calx of brass ; for green, 
calx of brass with scales of iron, or with cro- 
cus martis ; for black, zaffer with manganese, 
or with crocus martis ; or manganese with tar- 
tar; for red, manganese or calx of copper and 
red tartar ; for purple, manganese with calx of 
brass; for yellow, tartar and manganese ; and 
for violet-coloured enamel, manganese with 
thrice-calcined brass. 
In making these enamels, the following 
general cautions are necessary to be observ- 
ed. 1. That the pots must be glazed with 
white glass, and must be such as will bear 
the fire. 2. That the matter of enamels 
must be very nicely mixed with the colours. 
3. When the enamel is good, and the colour 
well incorporated, it must be taken from the 
fire with a pair of tongs. 4. The general 
way of making the coloured enamels is this; 
powder, sift, and grind all the colours very 
nicely, and first mix them with one another, 
and then with the common matter of ena- 
mels ; then set them in pots in a furnace, and 
when they are well mixed and incorporated, 
cast them into water, and when dry, set them 
in a furnace again to melt, and when melted 
take a proof of it. If too deep-coloured, add 
more ot the common matter of enamels, and 
it too pale, add more of the colours. 
Enamels are used either in counterfeiting 
or imitating precious stones, in painting in 
enamel, or by enamellers, jewellers, and gold- 
smiths, in gold, silver, and other metals. 
The first two kinds are usually prepared by 
the workmen themselves, who are employed 
m these arts. That used by jewellers, &c. 
is brought to us chiefly from Venice or Hol- 
land, in little cakes of different sizes, com- 
monly about four inches diameter, having 
the mark of the maker struck upon them 
with a puncheon. 
ENAMELLING, the art of laving en- 
amel upon metals, as gold, silver, copper, 
&c. and of melting it at the fire, or of mak- 
ing divers curious works in it at a lamp. It 
signifies also to paint in enamel. 
The method of painting in enamel. — This 
is performed on plates of gold or silver, or 
most commonly of copper, enamelled with 
the white enamel, which they paint with 
colours melted in the fire, where they 
take a brightness and lustre like that of 
glass. This painting is the most prized of 
all for its peculiar brightness and vivacity, 
which is very permanent, the force of its co- 
lours not being effaced or sullied with time, 
as in other painting, and continuing always 
as fresh as when it came out of the work- 
man’s hands. It is usual in miniature, it be- 
ing the more difficult the larger it is, by rea- 
son of certain accidents it is liable to in the 
operation. Fine enamelling should only be 
practised on plates of gold, the other metals 
being less pure: copper, for instance, scales 
with the application, and yields fumes; and 
silver turns the yellows white. Nor must 
the plate be made fiat; for in such case, the 
enamel cracks ; to avoid which, they usually 
forge them a little round or oval, and not too 
thick. The plate being well and evenly 
forged, they usually begin the operation by 
laying on a couch of white enamel, on both 
sides, which prevents the metal from swelling 
and blistering; and this first lay serves for 
the ground of all the other colours. The 
plate being thus prepared, they begin at first 
by drawing out exactly the subject to be 
painted with red vitriol, mixed with oil of 
spike, marking all parts of the design very 
lightly with a small pencil. After this, "the co'- 
lours (which are to be previously ground with 
water in a mortar of agate extremely fine, 
and mixed with oil of spike somewhat thick) 
are to be laid on, observing the mixtures and 
colours that agree to the different parts of the 
subject; for which it is necessary to under- 
stand painting in miniature. But here the 
workman must be very cautious of the good 
or bad qualities of the oil he employs to inix 
his colours with, for it is very subject to adul- 
terations, Great care must likewise be taken 
ENA 
that the least dust imaginable come not to 
your colours while you are either painting 
or grinding them; for the least speck, when 
it is worked up with it, and when the work 
comes to be put into the reverberatory to be 
red-hot, will leave a hole, and so deiace the 
work. When the colours are ail laid, the 
painting must be gently dried over a slow fire 
to evaporate the oil, and tne colours after- 
wards melted to incorporate them with the 
enamel, making the plate red-hot in a fire 
such as the enamellers use. Afterwards 
that part of the painting must be passed over 
again which the lire has any way effaced, 
strengthening the shades and colours, and 
committing it again to the fire, observing the 
same method as before, which is to be re- 
peated till the work is finished. 
i he white enamel ol which the glazing, 
of fine earthernware vessels consists, is made 
of 100 parts of lead melted with from 13 to- 
40 parts of tin, and the mixture is oxydized 
completely, by exposing it to heat in aij open 
vessel. One hundred parts of this oxide 
are mixed with an equal quantity of white 
sand, three parts of silica, one oi talc, and 
23 of common salt. This mixiure is melted* 
then reduced to pow r der, and formed into a 
kind of paste, which is spread over the porce- 
lain vessel before it is baked. The excel- 
lence of good enamel is, that it easily fuses 
into a kind of paste at the heat which is ne- 
cessary for baking porcelain, and spreads 
equally on the vessel, forming a smooth 
glassy surface, without losing its opacity, or 
flowing completely into a glass. Its w hite- 
ness depends on the proportion of tin, and its 
fusibility on the lead. 
Mr. Anness has just obtained a patent for 
enamels, of which the following are among his- 
principal directions. 
To prepare the fax or principal matter for 
enamelling on glass vessels. — Take one 
pound of sat urn us glorificatus (to prepare 
glorificatus thus: take litharge of white lead, 
put it in a pan, pour on distilled vinegar, 
stirring it well over a gentle fire till the vine- 
gar becomes impregnated with the salt of the 
lead ; evaporate half the vinegar, put it in a 
cool place to crystallize, and keep the crys- 
tals dry for use) ; half a pound of natural 
crystal calcined to a whiteness; one pound of 
salt of polverine, or other fit alkali ; mix them 
together, and bake in a slow heat for about 
12 hours, then melt the mass, and pulverize 
the same in an agate mortar, or any other 
proper vessel which is not capable of com- 
municating any metallic or other impurity. 
To make green. — Take one ounce of cop- 
per-dust, two ounces of sand, one ounce of 
litharge, half an ounce of nitre; or two of 
copper, one of sand, two of litharge, one 
and a half of nitre; mix them with equal 
parts of flux, or vary the proportions of them, 
as may be found necessary, according to the 
tint of colour required. 
To make black. — Take calcined iron one 
ounce, cobalt, crude or prepared, one ounce, 
or zaffer two ounces, and manganese one 
ounce ; mixed with equal parts of flux, by 
melting or grinding together. 
To make yelloiv. — Take of lead and tin 
ashes one ounce, litharge one ounce, anti- 
mony one ounce, sand one ounce, nitre four 
ounces; calcine or melt them together ; pul- 
verize ana mix them with a due proportiau 
oi flux, as the nature of the glass may re- 
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