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Of Insects
by Jonathan Edwards
OF all insects, no one is
more wonderful than the spider, especially with respect to their
sagacity admirable way of working. These spiders, for the present, shall
be distinguished into those that keep in houses and those that keep in
forests, upon trees, bushes, shrubs, etc. for I take ’em to be of very
different kinds and natures (there are also other sorts, some of which
keep in rotten logs, hollow trees, swamps and grass).
Of these last, everyone knows the truth of their marching in the air
from tree to tree, and these sometimes at five or six rods distance
sometimes. Nor can anyone go out amongst the trees in a dewy morning
towards the latter end of August or the beginning of September, but that
he shall see hundreds of webs, made conspicuous by the dew that is
lodged upon them, reaching from one tree and shrub to another that
stands at a considerable distance, and they may be seen well enough by
an observing eye at noonday by their glistening against the sun. And
what is still more wonderful, I know I have several times seen, in a
very calm and serene day at that time of year, standing behind some
opaque body that shall just hide the disk of the sun and keep off his
dazzling rays from my eye, multitudes of little shining webs and
glistening strings of a great length, and at such a height as (that one
would think they were tacked to the sky by one end, were it not that
they were moving and floating. And there often appears at the end of
these webs a spider floating and sailing in the air with them, which I
have plainly discerned in those webs that were nearer to my eye. And
once [I] saw a very large spider, to my surprise, swimming in the air in
this manner, and others have assured me that they often have seen
spiders fly. The appearance is truly very pretty and pleasing, and it
was so pleasing, as well as surprising, to me, that I resolved to
endeavor to satisfy my curiosity about it, by finding out the way and of
their doing it, being also persuaded that, if I could find out how they
flew, I could easily find out how they made webs from tree to tree.
And accordingly, at a time when I was in the woods, I happened to see
one of these spiders on a bush. So I went to the bush and shook it,
hoping thereby to make him uneasy upon it and provoke him to leave it by
flying, and took good care that he should not get off from it in any
other way. So I continued constantly to shake it, which made him several
times let himself fall by his web a little. But he would presently
‘creep up again, till at last he was pleased, however, to leave that
bush and march along in the air to the next, but which way I did not
know, nor could I conceive, but resolved to watch him more narrowly next
time. So I brought [him] back to the same bush again. To be sure that
there was nothing for him to go upon the next time, I whisked about a
stick I had in my hand on all sides of the bush, that I might break any
web going from it, if there were any, and leave nothing else for him to
go on but the clear air, and then shook the bush as before. But it was
not long before he again to my surprise went to the next bush. I took
him off upon my stick and, holding of him near my eye, shook the stick
as I had done the bush, whereupon he let himself down a little, hanging
by his web, and [I] presently perceived a web out from his tail and a
good way into the air. I took hold of it with my hand and broke it off,
not knowing but that I might take it out to the stick with him from the
bush; but then I plainly perceived another such string to proceed out at
his tail.
I now conceived I had found out the whole mystery. I repeated the trial
over and over again till I was fully satisfied of his way of working,
which I don’t only conjecture, to be on this wise, viz.: They, when they
would go from tree to tree, or would sail in the air, let themselves
hang down a little way by their web: and then put out a web at their
tails, which being so exceeding rare when it first comes from the spider
as to be lighter than the air, so as of itself it will ascend in it
(which I know by experience), the moving air takes it by the end, and by
the spider’s permission, pulls it out and bears it out his tail to any
length, and if the further end of it happens to catch by a tree or
anything, why, there’s a web for him to go over upon. And the spider
immediately perceives it and feels when it touches, much after the same
manner as the soul in the brain immediately perceives when any of those
little nervous strings that proceed from it are in the least jarred by
external things. And this very way I have seen spiders go from one thing
to another, I believe fifty times at least since I first discovered it.
But if nothing is in the way of those webs to hinder their flying out at
a sufficient distance, and they don’t catch by anything, there will be
so much of it drawn out into the air, as by its ascending force there
will be enough to carry the spider with it, or which is all one, till
there is so much of this web which is rarer than the air as that the
web, taken with the spider, shall take up as much or more space than the
same quantity [of air]. Of which, if it be equal they together will be
in perfect equilibrium or poise with the air, so as that when they are
loose therein they will neither ascend or descend, but only as they are
driven by the wind. But if they together be more, will ascend therein:
like as a man at the bottom of the sea, if he has hold on a stick of
wood, or anything that is lighter or takes up more space for the
quantity of matter than the water. If it be a little piece, it may not
be enough to carry him and cause him to swim therein, but if there be
enough of it, it will carry him up to the surface of the water (if there
be so much as that the greater rarity shall more than counterbalance the
greater density of the man); and if it cloth but just counterbalance,
put the man anywhere in the water and there he’ll keep, without
ascending or descending. ’Tis just so with the spider in the air as with
the man in the water, for what is lighter than the air will swim or
ascend therein, as well as that which is lighter than the water swims in
that. And if the spider has hold on so much of a web that the greater
levity of all of it shall more than counterpoise the greater gravity of
the spider, so that the ascending force of the web shall be more than
the descending force of the spider, the web, by its ascending, will
necessarily carry the spider up unto such a height, as that the air
shall be so much thinner and lighter, as that the lightness of the web
with the spider shall no longer prevail.
Now perhaps here it will be asked how the spider knows when he has put
out web enough, and, when he does know, how does he get himself loose
from the web by which he hung to the tree. I answer: there is no
occasion for the spider’s knowing, for their manner is to let out their
web until the ascending force of their web and the force the wind has
upon it, together with the weight of the spider, shall be enough to
break the web by which the spider hangs to the tree, for the stress of
all these comes upon that, and nature has so provided, that just so much
web as is sufficient to break, that shall be sufficient [to] carry the
spider. And [this] very way I very frequently have seen spiders mount
away into the air, with a vast train of glistening web before them, from
a stick in my hand, and have also showed it to others. And without doubt
they do it with a great deal of their sort of pleasure.
There remain only two difficulties. The one is how should they first
begin to spin out this so fine and even a thread of their bodies? If
once there is a web out it is easy to conceive how if the end of it were
once out, how the air might take it and so draw it out to a greater
length. But how should they at first let out of their tails the end of a
fine string, whereas in all probability the web, while it is in the
spider, is a certain liquor with which that great bottle tail of theirs
is filled, which immediately upon its being exposed to the air turns to
a dry substance and very much rarifies and extends itself. Now if it be
a liquor, it is hardly conceivable how they should let out a fine
string, except by expelling a small drop at the end of it, but none such
can be discovered. To find out this difficulty I once got a very large
spider of the sort; for in lesser ones I could not distinctly discern
how they did that, nor can one discern their webs at all except they are
held up against the sun or some dark place. I took this spider and held
him up against an open door, which, being dark, helped me plainly to
discern, and shook him. Whereupon, he let himself down by his web — as
in Figure 1, by the web cb — and then fixed with his tail one end of the
web that he intended to let out into the air to the web by which he let
himself down, at a. Then, pulling away his tail, one end of the web was
thereby drawn out, which being at first exceeding slender, the wind
presently broke it at d, and drew it out, as in Figure 2, and it was
immediately spun out to a very great length.
The other difficulty is, how when they are once carried up into the air,
how they get down again, or whether they are necessitated to continue,
till they are beat down by some shower of rain, without any sustenance —
which [is] not probable nor agreeable to nature’s providence. I answer:
there is a way whereby they may come down again when they please by only
gathering in their webs in to them again, by which way they may come
down gradually and gently. But whether that be their way or no I can’t
say — but without scruple, that or a better, for we always find things
done by nature as well or better than [we] can imagine beforehand.
Corollary. We hence see the exuberant goodness of the Creator, who hath
not only provided for all the necessities, but also for the pleasure and
recreation of all sorts of creatures, and even the insects and those
that are most despicable.
Another thing particularly notable and worthy of being inquired into
about these webs is that they, which are so exceeding small and fine as
that they cannot be discerned except held in a particular position with
respect to the sun or against some dark place when held close to the
eye, should appear at such a prodigious height in the air when near
betwixt us and the sun, so that they must needs some often appear as big
as a cable would do, if it appeared exactly secundum rationem distantiae.
To solve, we ought to consider that these webs, as they are thus
posited, very vividly reflect the rays of the sun, so as to cause them
to be very lightsome bodies, and then see if we can’t find any parallel
phenomena in other lightsome bodies. And everybody knows that a candle
in the night appears exceedingly bigger at a distance than it ought to
do, and we may observe in the moon towards the new, when that part of it
that is not enlightened by the sun, is visible, how much the enlightened
part thereof is enlarged and extended beyond the circumference of the
other parts. And astronomers also know how exceedingly the fixed stars
are beyond their bounds to our naked eye, so that without doubt they
appear many hundreds of times bigger than they ought to do. The reason
may be that the multitude and powerfulness of the rays affects a greater
part of the retina than their share, that which they immediately strike
upon. But we find that a light that so does when it is alone, and when
no part of the retina is affected by anything else but that, so that the
least impression is felt by it, won’t do — or at least not so much — in
the midst of other perhaps greater light, so that other parts of the
retina are filled with impressions of their own. But these webs are
instances of the latter, so that this reason does not seem fully to
solve this so great a magnifying, though without a doubt that helps. But
the chief reason must be referred to that incurvation of the rays
passing by the edge of any body, which Sir Isaac Newton has proved.
One thing more I shall take notice of, before I dismiss this subject,
concerning the end of nature in giving spiders this way of flying, which
though we have found in the corollary to be their pleasure and
recreation, yet we think a greater end is at last their destruction. And
what makes us think so is because that is necessarily and naturally
brought to pass by it, and we shall find nothing so brought to pass by
nature but what is the end of those means by which is brought to pass;
and we shall further evince it by and by, by strewing the great
usefulness of it. But we must show how their destruction is brought to
pass by it.
I say then, that by this means almost all the spiders upon the land must
necessarily be swept first and last into the sea. For we have observed
already that they never fly except in fair weather. We may now observe
that it is never fair weather, neither in this country nor any other,
except when the wind blows from the midland parts, and so towards the
sea. So, here in New England, I have observed that they never fly except
when the wind is westerly, and I never saw them fly but when they were
hastening directly towards the sea. And [the] time of the flying being
so long, even from the middle of August to the middle of October —
though their chief time here in New England is in the time as was said
before, to wit, the latter end of August and the beginning of September
— and they keep flying all that while towards the sea, [they] must needs
almost all of them get there before they have done. And the same indeed
holds true of all other sorts of flying insects, for at that time of
year the ground, trees and houses, the places of their residence in
summer, being pretty chill, they leave ’em whenever the sun shines
pretty warm, and mount up into the air and expand their wings to the
sun. And so, flying for nothing but their ease and comfort, they suffer
themselves to go that way that they find they can go with greatest ease,
and so wheresoever the wind pleases. And besides, it being warmth they
fly for, and it being warmer flying with the wind than against it or
sideways to it — for thereby the wind has less power upon them — and as
was said of spiders, they never flying but when the winds that blow from
the midland parts towards the sea bring fair weather, they must
necessarily, flying so long a time, all the while towards the sea, get
there at last. And I very well remember, that at the same time when I
have been viewing the spiders with their webs in the air, I also saw
vast multitudes of flies, many of ’em at a great height, all flying the
same way with the spiders and webs, directly seaward. And I have many
times, at that time of year, looking westward, seen myriads of them
towards sun setting, flying continually towards the sea. This, I
believe, almost everybody, if not all, of my own country will call to
mind that they have also seen. And as to other sorts of flying insects,
such as butterflies, millers, moths, etc., I remember that, when I was a
boy, I have at the same time of year lien on the ground upon my back and
beheld abundance of them, all flying southeast, which I then thought
were going to a warm country. So that, without any doubt, almost all
manner of aerial insects, and also spiders which live upon them and are
made up of them, are at the end of the year swept and wafted into the
sea and buried in the ocean, and leave nothing behind them but their
eggs for a new stock the next year.
Corollary 1. Hence also we may behold and admire at the wisdom of the
Creator, and be convinced that is exercised about such little things, in
this wonderful contrivance of annually carrying off and burying the
corrupting nauseousness of our air, of which flying insects are little
collections, in the bottom of the ocean where it will do no harm, and
especially the strange way of bringing this about in spiders (which are
collections of these collections, their food being flying insects) which
want wings whereby it might be done. And what great inconveniences
should we labor under if there were no such way. For spiders and flies
are so exceeding multiplying creatures that if they only slept or lay
benumbed in [winter] and were raised again in the spring, which is
commonly supposed, it would not be many years before we should be as
much plagued with their vast numbers as Egypt was. And if they died for
good and all in winter they, by the renewed heat of the sun, would
presently again be dissipated into those nauseous vapors which they are
made up of, and so would be of no use or benefit in that [in] which now
they are so very serviceable.
Corol. 2. Admire also the Creator in so nicely and mathematically
adjusting their multiplying nature, that notwithstanding their
destruction by this means and the multitudes that are eaten by birds,
that they do not decrease and so, little by little, come to nothing; and
in so adjusting their destruction to their multiplication that they do
neither increase, but taking one year with another, there is always just
an equal number of them.
Another reason why they will not fly at any other time but when a dry
wind blows, is because a moist wind moistens the web and makes it
heavier than the air. And if they had the sense to stops themselves, we
should have hundreds of times more spiders and flies by the seashore
than anywhere else.
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