A R A 
kind of poifon ; but Dr. Mead, in his “ EiTay on Poifons,” 
di(Tents wholly from this opinion, having neve; - been able, 
on repeated examinations, to difeover any inch opening, 
not even in the claws of the larged foreign fpider; w hich 
being above fifty times larger than any of the European 
fpiders, would more ealily have afforded a view of this 
opening, if nature had allotted any to this part of the ani¬ 
mal. Befides, repeated obfervations alfo convinced him 
that nothing dropped out of the claws, which went always 
dry while the fpider bit any thing, but that a fhort white 
probofeis was at the fame inftant thruft out of the mouth, 
which inllilled a liquor into the wound. And the fame 
author obferves, that the quantity of liquor emitted by 
our common fpiders when they kill their prey, is vifibly 
fo great, and the w ounding weapons fo minute, that they 
could contain but a very inconfiderable portion thereof, 
if it were to be difeharged that way. Baker's Micro [cope, 
p. 196. Spiders frequently call: their (kins, which may be 
found in the webs, perfe&ly dry and tranfparent; and 
from fuch fkins the forceps, or claw's, for they are always 
filed with the (kins, may eafier be feparated, and examined 
with much greater exadtnefs than in the common fpider 
while living. 
Spiders have five tubercles, or nipples, at the extremity 
of the belly, whole apertures they can enlarge or contrail 
at pleafure. It is through thefe apertures that they fpin 
a gluey fubdance with w hich their bellies are full. They 
fix the end of their threads by applying thefe nipples to 
any fubdance, and the thread lengthens in proportion as 
the animal recedes^.from it. They can dop the illuing of 
the threads by contracting the nipples, and re-afeend by 
means of the claws on their feet, much in the fame manner 
as fome menw'arp up a rope. When the common houfe- 
fpider begins her web, die generally choofes a place where 
there is a cavity, fuch as the corner of a room, that (lie 
may have a free paffage on each fide, to make her efcape 
in cafe of danger. Then die fixes one end of her thread 
to the wall, and paffes 011, dragging the thread along with 
her, till die arrives at the other fide, and tiiere fixes the 
other end of it. Thus die paffies and repaffes, till die has 
made as many parallel threads as die thinks necelfary for 
her purpofe. After this, die begins again, and erodes thefe 
by other parallel threads, which may be named the woof. 
Thefe are the toils or fnares which die prepares for en¬ 
tangling dies, and other fmall infe&s, which happen to 
alight upon it. But, befides this large web, (lie generally 
weaves a fmall cell for herfelf, where (he lies concealed 
watching for her prey. Betwixt this cell and the large 
web die has a bridge of threads, which, by communicating 
with the threads of the large one, both give her early in¬ 
telligence when any thing touches the web, and enables 
her to pafs quickly in order to lay hold of it. There are 
many other methods of weaving, peculiar to different fpe- 
cies of fpiders ; but, as they are all intended for the fame 
purpofe, it is needlefs to give particular deferiptions of 
them. The matter of which the fpider’s threads are form¬ 
ed, is a vifeid juice, elaborated in the body of the animal, 
and emitted from papillae fituated at the extremity of the 
belly ; which papillae are furniflied with numerous aper¬ 
tures that do the bufinefs of wire-drawers, as it were, in 
forming the threads. Of thefe apertures M. Reaumur 
obferves, there are enough in the compafs of the dualled 
pin’s head to yield a prodigious quantity of diftinCt threads. 
M. Reaumur has often counted feventy or eighty with a 
microfcope, but has perceived that there were infinitely 
more than he could tell. In effeft, if he fhould fay that 
each tip of a papilla furnifiied a thoufand, he is perfuaded 
he fhould fay much too little; corifequently the fpider, 
having five papillae, has hales for about five thoufand 
threads. Such is the tenuity of the threads in the larger 
fort of fpiders. But, if we examine the young produced 
by thofe, we (hall find that they no fooner quit their egg 
than they begin to fpin. Indeed their threads can fcarcely 
be perceived, but the webs may : they are frequently as 
thick and clofe as thofe of houfe-lyiders: and no wonder, 
N E A. 551 
there being often four or five hundred little fpiders con¬ 
curring to the fame work. How minute mud their holes 
be! the imagination can fcarcefy conceive that of their 
papillae! The whole fpider is perhaps lefs than a papilla 
of the parent which produced it. But there are even fome 
kinds of fpiders fo fmall at their birth, that they are not 
vifible without a microfcope. There are ufually found an 
infinity of thefe in a duller, and they only appear like a 
number of red points; and yet there are webs found under 
them, though a!molt imperceptible. What mud be the 
tenuity of one of thefe threads ? Mr. I.euwenhoek has 
computed that one hundred of the Tingle threads of a full- 
grown fpider are not equal to the diameter of the hair of 
his beard ; and confequently, if the threads and hair be 
both round, ten thoufand fuch threads are not larger than 
fuch a hair. He calculates farther, that, when young fpi¬ 
ders firlt begin to fpin, four hundred of them are not lar¬ 
ger than one which is of a full growth; allowing which, 
four millions of a young fpider’s threads are not fo large 
as the Tingle hair of a man’s beard! 
Gardcn-fpiders, particularly the (liort-legged fpecies, 
yield a kind of (ilk, which has by fome been judged little 
inferior to that of the (ilk-worm. Mr. Bon, of Languedoc, 
about eighty years ago, contrived to manufacture from it 
a pair of (ilk (lockings and mittens, of a beautiful natural 
grey colour, which were almofl as handfome and llrong as 
thofe made with common (ilk ; and lie publifhed a differ- 
tation concerning the difeovery. But M. Reaumur, being 
appointed by the Royal Academy to make a farther inquiry 
into this new filk-work, raifed feveral objections and diffi- , 
culties againfl it, which are found in the Memoirs of the 
Academy for the year 1710. The fum of what he has 
urged amounts to this: the natural fiercenefs of fpiders 
renders them unfit fo be bred and kept together : four or 
five thoufand being diflributed into ceils, fifty in fome, 
one or two hundred in others, the large ones foon killed 
and ate the lefs, fo that, in a fhort time, there were fcarcely 
left one or two in each cell; and to this inclination of mu. 
tually eating one another, M. Reaumur aferibes the fear- 
city of fpiders, confidering the vaft number of eggs they 
lay. But this is not all: he even affirms, that the lpider’s 
bag is inferior to that of the filk-worm both in luftre and 
llrength, and that it produces lefs matter to be manufac¬ 
tured. The thread of the fpider’s web, he fays, only bears 
a weight of two grains without breaking; and that of the 
bag bears thirty-fix. The latter, therefore, in all proba¬ 
bility, is eighteen times thicker than the former; yet it is 
weaker than that of the filk-worm, which bears a weight 
of two drams and a half: fo that five threads of the fpi¬ 
der’s bag mull be put together to equal one thread of the 
filk-wovm’s bag. Now it is impoffible thefe fhould be 
applied fo judly over one another as not to leave little va¬ 
cant fpaces between them, whence the light will not be 
reflected; and, of confequence, a thread thus compounded 
mud fall fhort of the luftre of a folid thread. Add to this, 
that the fpider’s thread cannot be wound off, as that of the 
filk-worm may, but mud ofneceffity be carded ; by which 
means, being torn in pieces, its evennefs, which contri¬ 
butes much to its luftre, is deftroyed. In effeCt, this want 
of luftre was taken notice of by M. de la Hire, when the 
dockings were prefented to the Academy. Again, fpiders 
furnifh much lefs filk than the worms: the larged bags 
of thefe latter weigh four grains, the fmaller three grains; 
fo that 2304 worms produce a pound of filk. The fpider- 
bags do not weigh above one grain ; yet, when cleared of 
their dud and filth, they lofe tw’o-thirds of their weight. 
The work of twelve fpiders, therefore, only equals that 
of one filk-worm ; and a pound of filk will require at lead 
27,648 fpiders. But as the bags are wholly the work of 
the females, who fpin them to depofit their eggs in, there 
mu(t be kept 55,296 fpiders to yield a pound of filk. Yet 
will this only hold of the bed fpiders; thofe large ones 
ordinarily feen in gardens, &c. fcarcely yielding a twelfth 
part of the filk of the others. Two hundred and eighty 
of thefe, he proves, would not yield more than one filk- 
worm ; 
