482 CONCH 
Of the Ha- performing tins work with nicety : very often (hells are 
SheUs° P &c cut . dow . n t0 ° ^ ar b y jh. and wholly fpoiled and to 
'■ ..L~f ’ '■ avoid this, a coarfe vein mull be often left (landing in 
fome place, and taken down afterwards with the file, 
when the cutting it down at the wheel would have 
# filed the adjacent parts. 
After the (hell is thus cut down to a proper degree, 
it is to be polilhed with fine emery, tripoli, or rotten 
/lone, with a wooden wheel turned by the fame machine 
as a leaden one, or by the common method of working 
with the hand with the fame ingredients. When a 
(hell is full of tubercles or protuberances which mud 
be preferved, it is then impoflible to ufe the wheel : 
and if the common way of dipping into aquafortis be 
attempted, the tubercles being harder than the reft of 
the (hell, will be corroded before the reft is fufficiently 
foaled, and the (hell will be fpoiled. In this cafe, in- 
duftry and patience are the only means of effe&ing a 
polifti. A camels-hair pencil muft be dipped in aqua- 
fortis 5 and with this the intermediate parts of the (hell 
muft be wetted, leaving the protuberances dry : this is 
to be often repeated ; and after a few moments the (hell 
is always to be plunged into water to flop the erofion 
of the acid, which would otherwife eat too deep, and 
deftroy the beauty of the (hell. When this has fuffici- 
ently taken off the foulnefs of the (hell, it is to be po- 
liffied with emery of the fined kind, or with tripoli, by 
means of a fmall (lick j or the common poliffiing-ftone 
iiled by the goldfmiths may be ufed. 
_ This is a very tedious and troublefome thing, efpe- 
cially when the echinated oyllers and murices, and 
fome other fuch (hells, are to be wrought : and what is 
word of all is, that when all this labour has been em- 
ployed, the bufinefs is not well done ; for there (till 
remain feveral places which could not be reached by 
any inftrument, fo that the (hell muft neceffarily be 
rubbed over with gum-water or the white of an egg 
afterwards, in order to bring out the colours and give 
a glofs ; in fome cafes it is even neceffary to give a 
£ coat of varniffi. 
Some ihells Thefe are the means ufed by artifts to brighten the 
are dif- colours and add to the beauty of (hells > and the 
gU pv by clian § es P roc ’ luced b y polifhing in this manner are fo 
4°b as"” § rea *"’ can fcarcely be known afterwards 
to be the iame it was •, and hence we hear of new (hells 
in the cabinets of colleflors, which have no real exif- 
tence as feparate fpecies, but are (hells well known, 
difguifed by polifhing. To caution the reader againft 
errors of this kind, it may be proper to add the moft re- 
markable fpecies thus ufually altered, 
the onyx- . The onyx-ffiell or volute, called the purple or violet- 
ftell. tip, which in its natural date is of a limple pale brown, 
when it is wrought (lightly, or poliffied with juft the 
fuperfices taken off, is of a fine bright yellow $ and 
when it is eaten away deeper, it appears of a fine milk- 
white, with the lower part bluifli : it is in this (late 
that it is called the onyx-Jhell ; and it is preferved in 
many cabinets in its rough (late, and in its yellow ap- 
548 pearance, as different fpecies of (hells. 
Violet The violet Jbeil , fo common among the curious, is 
Ihells. a fpecies of porcelain, or common cowry, which does 
not appear in that elegance till it has been poliffi- 
ed ; and the common fea-car (hows itfelf in two or 
three different forms, as it is more or lefs deeply 
wrought. In its rough date it is dufey and coarfe, of 
0 1,- O' GY. Chap. VI. 
a pale brown on the outfide, and pearly within ; when Of the Ha- 
it is eaten down a little way below the furface, it (hows Station of 
variegations of black and green 5 and when ftill farther Shel] s,&c. 
eroded, it appears of a fine pearly hue within and l, “V— 
without. 
The nautilus, when it is polilhed down, appears all Nautilus, 
over of a fine pearly colour ; but when it is eaten 
away but to a fmall depth, it appears of a fine yellowiffi 
colour with duiky hairs. The burgau, when entirely 
cleaved of its coat, is of the moft beautiful pearl co- 
lour : but when (lightly eroded, it appears of a va- 
riegated mixture of green and red ; whence it has 
been called the parroquet Jljell. The common helmet- 
ffiell, when wrought, is of the colour of the fineft 
agate ; and the muffels, in general, though very plain 
(hells in their common appearance, become very beau- 
tiful when poliffied, and (how large veins of the moft 
elegant colours. The Perfian (hell, in its natural ftate, 
is all over white, and covered with tubercles j but when 
it has been ground dow'n on a wheel, and polilhed, it 
appears of a gray colour, with fpots and veins of a 
very bright and highly poliffied white. The limpets, in 
general, become very different when poliffied, moft; of 
them (bowing very elegant colours ; among thefe the 
tortoife-ffiell limpet is the principal ; it does not appear 
at all of that colour or tranfparence till it has been 
wrought. 
That elegant fpecies of (hell called the jonquil-cla- j on q U S j° 
ma, wjiich has deceived fo many judges of thefe things chama. 
into an opinion of its being a new fpecies, is only a 
white chama with a reticulated furface 5 but when this 
is poliffied, it lofes at once its reticular work and its 
6olour, and becomes perfectly fmooth, and of a fine 
bright yellow. The violet-coloured chama of New 
England, when worked down and poliffied, is of a fine 
milk-white, with a great number of blue veins, difpo- 
fed like the variegations in agates. 
The ajjes-ear Jhell , when poliffied after working it Theses- 
down with the file, becomes extremely gloffy, and ob- ear Ihell. 
tains a fine rofe-colour all about the mouth. Thefe are 
fome of the moft frequent among an endlefs variety of 
changes wrought on (hells by poliffiing ; and we find 
there are many of the very greateft beauties of this part 
of the creation which muft have been loft but for this 
method of fearching deep in the fubftance of the (hell 
for them. 
The Dutch are very fond of (hells, and are veryj) utc ^ * _ 
nice in their manner of working them ; they are under thod of po- 
no reftraint, however, in their works ; but ufe the moft lifting 
violent methods, fo as often to deftroy all the beauty 
the (hell. They file them down on all (ides, and often 
take them to the wheel, when it muft deftroy the very 
charafters of the fpecies. Nor do they (top here : 
but determined to have beauty at any rate, they are 
for improving upon nature, and frequently add fome 
lines and colours with a pencil, afterwards covering 
them with a fine coat of varniffi, fo that they feem the 
natural lineations of the (hell : the Dutch cabinets are 
by thefe means made very beautiful, but they are by 
no means to be regarded as inftru&ors in natural hif- 
tory. There are fome artificers of this nation who have 
a way of covering (hells all over with a different tinge 
from that which nature gives them ■, and the curious 
are often enticed by thefe tricks to purchafe them for 
new fpecies. 
There 
