PEA 
miner who accompanied him, insisted that 
tins water ebbed and flowed with the sea ; 
but the captain disproved this assertion, by 
remaining in the place from three hours flood 
to two hours ebb, during which time there 
was no alteration in the height of the water. 
As they walked by the side of this water, 
they observed a hollow in the rock some feet 
above them. The miner went into this 
place, which was the mouth of another ca- 
vern; and walked for about 70 paces in it, 
till he just lost sight of the captain. Ha then 
called to him, that he had found a rich mine, 
but immediately after came running out, and 
crying that he .had seen an evil spirit ; nor 
could any persuasions induce him to re- 
turn. The floor of these caverns is a kind of 
white stone enamelled with lead ore, and the 
roofs are encrusted with shining spar. On 
his return from this subterraneous journey, 
captain Sturmv was seized with a violent 
head-ache, which, after continuing four days, 
terminated in a fever, of which he died in a 
short time. 
Several years ago this cavern was visited 
by the late Mr. James Ferguson, who tells 
us, 'that it consists -of two hollows one over 
another ; but that the mouth of the lower- 
most is now stopped up by planks of timber 
laid across it, on which is a heap of stones 
thrown in at the upper mouth, with a design 
to fill up the cavern entirely ; which, how- 
ever, will probably be never accomplished, 
on account of its vast size. 
PEAR, in botany. See Pyrus. 
PE ARC II, in ichthyology. See Perca. 
PEARL, in natural history, a hard, white, 
shining body, usually roundish, found in va- 
rious kinds of testaceous lishes. 
Pearls, though esteemed of the number of 
gems by our jewellers, and highly valued, 
net only at this time, but in all ages, proceed 
only from a distemper in the creature that 
produces them, analogous to the bezoars aiid 
other stony concretions in several animals of 
oilier kinds. 
The fish in which the largest and finest 
pearls are usually produced, is the East In- 
dian pearl-oyster, as it is commonly called. 
Besides this shell there are many others that 
are found to produce pearls ; as the common 
I * oyster, the muscle, and several others, the 
pearls of which are often very good ; but 
those of tbe true Indian berberi, or pearl-oy- 
ster, are in general superior to ail. r I he 
small or seed-pearls, also called ounce-pearls, 
from their being sold by the ounce and not 
by tale, are vastly the most numerous and 
common ; but, as in diamonds, among the 
multitudes of small ones, there are smaller 
numbers and larger found, so in pearls there 
are larger and larger kinds ; but as they in- 
crease in size, tiiey are proportionably less 
frequent ; and this is one reason ol their great 
price. We have Scotch pearls frequently as 
large as a little tare, some as big as a large 
pea, and some few of the size ot a horse- 
bean ; but tiiese are usually of a bad shape, 
and of little value in proportion to their 
weight. Philip 11. of Spain had a pearl per- 
fect in its shape and colour, and of the size ot 
a pigeon’s egg. The finest, and what is called 
the true shape of the pearl, is a perfect round ; 
but if pearls of a considerable size are of the 
shape of a pear, as is not unfrequently the 
case, they are not less valued, as they serve 
T E A 
for ear-rings and other ornaments. Their 
colour ought to be a pure white ; and that 
not a dead and lifeless, but a clear and bril- 
liant one : they must be perfectly free from 
any foulness, spot, or stain; and their sur- 
faces mud be naturally smooth and glossy; 
for they bring their natural polish with them, 
which art is not able to improve. 
All pearls are formed ol the matter of the 
shell, and consist of a number ot coats spread 
with perfect regularity one over another, in 
the manner of the several coats ot an onion, 
or like the several strata ot the stones found 
in the bladders or stomachs of animals, only 
much thinner. 
The manner of fishing for pearls in the 
East Indies is this: There are two seasons for 
pearl-fishing ; the first is in March and April, 
and the last in August and September; and 
the more rain there falls in the year, the 
more plentiful are these fisheries. At the 
beginning of the season there are sometimes 
250 barks on the banks: the larger barks 
have two divers, and the smaller one. As 
soon as barks arrive at the place where the 
fish lie, and have cast anchor, each diver 
binds a stone, six inches thick and a foot 
long, under his body, which serves him as a 
ballast, prevents his being driven away by 
the motion of the water, and enables him to 
walk more steadily under the waves. They 
also tie another very heavy stone to one foot, 
by which they are very speedily sent to the 
bottom of the sea : and as the oysters are 
usually firmly fastened to the rocks, they arm 
their hands with leather mittens, to prevent 
their being wounded in pulling them vio- 
lently off; but this task some perform with 
an iron rake. In the last place, each diver 
carries down with him a large net, in the 
manner of a sack, tied to his neck by a long 
cord, the other end of which is fastened to 
the side of the bark. This net is to hold the 
oysters gathered from the rock ; and the cord 
is” to pull up the diver when his bag is full, or 
when he wants air. In this equipage he some- 
times precipitates himself sixty feet under 
water; and as he has no time to lose, he no 
sooner arrives at the bottom, than he begins 
to run from side to side, tearing up all the 
oysters he meets with, and cramming them 
into his budget. 
At whatever depth the divers are, the light 
is so great, that they easily see whatever 
passes in the sea ; and, to their great con- 
sternation, sometimes perceive monstrous 
fishes, from which all their address injmid- 
dying the water, &c. will not save them, but 
they unhappily become their prey : and ot 
all the dangers of the fishery this is one ot 
the greatest and most usual. r l he best divers 
will keep under water near halt an hour, and 
the rest do not stay less than a quarter. 
During this time they hold their breath, 
without the use of oils or any other liquors; 
only acquiring the habit by long practice. 
When they find themselves Straitened, they 
pull the rope to which the bag is fastened, 
and hold fast by it with both hands ; when 
those in the bark, taking the signal, heave 
them up into the air, and unload them ot 
their fish ; which is sometimes 500 oysters, 
and sometimes not above 50. Some ot the 
divers need a moment’s respite to recover 
breath ; others jump in again instantly, con- 
tinuing this violent exercise without intermis- 
sion for several hours. 
PEA 
On the shore they unload their barks, and 
lay their oysters in an infinite number of 
little pits dug in the sand tour or five leet 
square, raising heaps of sand over them to 
the height of a man ; and in this condition 
they are left till the rain, wind, and sun, have 
obliged them to open, which soon kills them : 
upon this the flesh rots and dries ; and the 
pearls, tints disengaged, fall into the pit on 
their taking out the shells. After clearing 
the pits of the grosser filth, they sift the sand 
several times, in order to find the pearl ; but, 
whatever care they take, they always lose a 
great many. After cleaning and drying the 
pearls, they are passed through a kind ot 
sieve, according to their sizes ; the smallest 
are then sold as seed pearls, and the vest put 
up to auction, and sold to the highest bidder. 
See also Mya : and for the composition of 
the pearl, see the next article. 
]\Iotlisr~oJ- Pearl, is the shell not of the 
pearl oyster, Tut of another sea-fish of the 
oyster kind. This shell on the inside is ex- 
tremely smooth, and of the whiteness and 
water of pearl itself ; and it has the same 
lustre on tbe outfide, after the first lamina* or 
scales have been cleared oft with aquafortis* 
and the lapidary’s mill. Mother-of-pearl is 
used in inlaid works, and in several toys, as 
snuff-boxes, <5cc. 
Mother-of-pearl shells, when exposed to 
a red heat, crackle, blacken, and emit a 
strong fetid odour. They exfoliate, and be- 
come grey and white; when immersed in 
acids, they effervesce. The acids take up 
only the lime, and leave a number of thin 
membranaceous substances, which still re- 
tain the form of the shell. From Mr. 
Hatchett’s experiments we learn, that these 
membranes have the properties of coagulated 
albumen. Mother-of-pearl shells then are 
composed of alternate layers ot coagulated 
albumen and carbonat of lime, beginning 
with the epidermis, and ending with the last- 
formed membrane. The animals which in- 
habit these shells increase their habitation by 
the addition of a stratum of carbonat of lime, 
secured bv a new membrane ; and as every 
additional” stratum exceeds in extent that 
which was previously formed, the shell be- 
comes stronger as it becomes larger. 
Though this in general is the structure of 
the mother-of-pearl shells, yet there is a con- 
siderable difference between the proportion 
of the component parts, and the consistency 
of the albuminous part. Some ot them, as 
the common oyster-shell, approach neatly to 
the patella:, the albuminous portion being 
small, and its consistence nearly gelatinous ; 
while others, as the haliotis it is, the tuibo 
ol ear ius, the real mother-of-pearl, and a spe- 
cies of fresh-water muscle . analysed by 
Hatchett, the membranes are distinct, thin, 
compact, and semitransparent. Mother-of- 
pearl contains 
G6 carbonat of lime 
34 membrane 
100 . 
The pearl which is formed in some of these 
shells (see the preceding article) resembles 
them exactly in its structure and composi- 
tion. It is a heautiful substa; ce of a blueish- 
white colour, iridescent, and brilliant. It is 
composed of concentric and alternate cost a 
