« ZurückWeiter »
it has spun may be close twisted, just as in a pully, on which the clockmakers put their lines to fasten the weight on, wilich in the beginning is wide and large, but the longer it grows the narrower it is.
The fig. ABCDEF represents a small part of the leg of a spider; BCD show the two extreme claws, armed with teeth like saws; E the third that has no teeth; which claw I suppose he uses on several accounts; this is certain, that when the spider does not wind himself by his thread upwards, but runs along E his web, then he takes hold of the spun thread with this third claw. The above-mentioned spider is provided with eight long and two short legs; which last stand out on each side of the head, having such claws, as are before mentioned. Further, I discovered eight distinct eyes, two of which are on the top of the head, in order to see what passes above him. Below those were two other eyes, to look straight forwards. On each side of the head were two more, close to each other; the two foremost eyes to see, I suppose, what passed collaterally before him, the two hindmost to see the same backwards.
The engraving shows
the fore part of the body M
separated from the memI brane or pellicle it lay in;
PQ the eyes that look N
upwards; KL those that P
look straightforwards ; vhod,
IM those that look side ways forward; HN those sideways backward. Now as the spider's eyes are immoveable, having no muscles belonging to them,
it is easy to conceive how necessary eight eyes are, in order to look round about, the more easily to catch his prey.
I found that the spider has two instruments or cases for his sting, in the fore-part of his head, which, when he does not use, he places in great order under his eyes, and between his two short legs. These stings are crooked like a claw, and very much resemble the stings of scorpions, or Indian
millepedes. The stings of a spider have towards the end, and on each side, a little hole, from whence, according to all appearance, when he strikes his enemy, he ejects a liquid matter, which we call poison.
When I put two or three of the largest sort of spiders together in the glass, I observed that when they met, they never parted without an engagement, in which one has been sometimes wounded in such a manner, that his body was wet with the blood spilt in the battle, and that he died soon after. I always observed that the lesser fled from the greater; and when it happened that two of an equal size met together, neither retired, but held one another so fast by their stings, that one would remain dead without once stirring, and as wet with the blood it had lost, as if it had lain some time in the water. I had one spider that was wounded by his antagonist in the thickest part of his leg, from whence issued one drop of blood as large as a sand grain; not being able to use this wounded leg in running away from his enemy, he raised it up on end, and presently after the whole limb fell off from his body; and I have observed, that when they are wounded in the breast, or upper part of their bodies, they always die.
When I formerly opened or dissected a spider, in order to discover that viscous matter, which I took to be the beginning of their web, and not finding it, I was amazed, being unable to conceive how such a strong thread could in so short a time proceed out of such a moist body, strong enough to bear the weight not of one only, but even six spiders; and when I endeavoured to find out the manner how they make their webs, one and the same thread seemed to me sometimes to consist of a single thread, and sometimes of four or five; but I could never see how the threads issued from the spider's body. Since then, I took a spider, and laid it on its back, so that it could not stir, and with a very fine pair of pincers drew out a thread, which I could perceive sticking out of one of the working instruments; in doing which I saw abundance of very fine threads coming out of the body at the same time; which, as soon as they were one or two hair's breadth distant from the body, were joined together, and so made thick threads.
Now, as we may perceive that a spider's web, which to our naked eye seems but single, yet consists of many other threads, and thus acquires a greater strength; we may from hence certainly conclude, that no flexible bodies (excepting metals, whose parts are strongly cemented by the force of fire,) can attain to any degree of strength, unless they consist of long united parts; and the more these are twisted together, or cemented with any viscous matter, the stronger they are ; which is very obvious in flax, or silken thread,
To endeavour to discover the internal machinery of these curious threads, I proceeded to the dissection of the body of one of the largest spiders I could get, and very curiously investigated each part of it; and, at last, to my great amazement, I discovered the vast number of instruments from whence each single thread proceeded; indeed the number was so great, that I judged them to be at least 400: yet they did not lie close by one another, but were divided into eight distinct parts or instruments; so that if the spider set all these eight instruments to work at once, there would proceed from the same eight particular threads, which were again subdivided into a great number of smaller; but one of the great threads would be thicker than the other, because one part of the body would produce twice as many threads as the other just by it.
I once took a very small frog, the length of whose body was about an inch and a half, and put him into a glass tube, together with a large spider, in order to see how they would behave ; when I observed, that the spider passed by the frog without touching him, but yet he had drawn out his stings, as if he intended to have fallen directly upon the frog. Afterwards I caused the frog to run against the spider, who thereupon struck it in the back with its stings, and wounded the frog in two several places, in such a manner, that in one place he left a red speck, and in the other a blue one. Hereupon I brought them together again; when the spider struck his stings into the fore-leg of the frog, who upon that strug. gled so hard that the spider was forced to leave him; and I observed that some few of the blood vessels in the frog's legs were wounded. Once again I forced the frog to jostle the spider, who upon that struck both his stings into the frog's nose, after which they both stood still about half a minute: then opening the glass I took the spider out, while the frog sat still about an hour, then stretched out his hinder legs, and died.
I took a spider's eggs, and putting them into a glass tube, carried them about me, to see if they would hatch. They were laid by the largest spider that I had seen the last summer, and it was one of the last I could meet with in the gardens. On the 17th of the same month, in the morning, viewing them again, I saw 25 young spiders that were come
out of so many eggs, and about 25 more whose bodies were but - half out of the egg-shell, and some of them had their shells hanging upon their tail ; and in the evening, about six o'clock, I reckoned 150 young ones. The next day I viewed them again, and then I concluded that no more spiders would come out of the eggs, and that several which I saw lying about the glass were barren, and that in others the young spiders were dead; the number of which I judged to be about 50; and about 10 or 12 eggs were blackish. When the glass tube, where the young spiders were, had been out of my pocket but 15 minutes, in very cold weather, I could hardly discover any life or motion in some of them; but so soon as the glass tube had been a little warmed again, they were brisk and lively, and most of them got together in a company, as we see in swarms of bees, and so hung about the web, where the eggs had been lodged before.
January 21st, I could perceive the eight eyes in every spider, which before were not so visible; but now being of a brown or darkish colour, they were easily distinguishable from the fore-part of their body, which was white, as the hinder part was yellowish.
January 22d, I observed that the legs of many of the spiders, which before had been clear and transparent, now assumed a dark colour, and afterwards began to be covered with hair; whereas I could perceive none a little before.
On the 23d, their legs grew darker, as also the hinder part of their bodies, whence their web proceeds, and that also began to be covered with hairs; I observed, also, that they had cast their very thin skins, and began to be much nimbler in their motions.
The 25th, I saw them spin a thread, and manage it with their hinder-feet as well as the old ones; I observed, also, that they had eaten up the barren eggs, and the others wherein I supposed the young ones to be dead, which where about 50 in number: for a few days after there remained nothing but the bare shells.
I have compared the threads of a full-grown spider with one of the hairs of my beard; the thickest part of which was placed before the microscope; and according to the nicest observation, I judged that above 100 of those threads laid together did not equal the diameter of one hair ; now sup posing this hair to be round, then 100 of the fine threads of a spider's web are not thicker than one single hair.
Now if we add to this, as it is most certainly true, that 400 young spiders, when they first begin to spin, are not, one with another, larger than one full-grown spider, and that each of those young ones is provided with all the working instruments of the old one, it would follow that the smallest thread of such a young spider is 400 times smaller than that of a large me, and if so, then 4,000,000 threads of a young spider are not so large as a hair ; but then again, if we consider of how many parts one of those smallest threads consist, we stand astonished at the thought.
January 30th, most of them were employed in weaving their web, so that the glass swarmed with them. February 8th, I could perceive that many of the spiders had eaten each other up; and at the very time I looked on them, there were four upon one, whom they had almost devoured; and here and there I saw pieces of legs ; and now the shells of the barren eggs were eaten up so clear, that I could see nothing of them remaining.
February 10th, my spiders were reduced to half their number, and those that remained were eating the thickest of their companions' legs. Thus they diminished daily, so that on the last of the said month I could see but 30 of them alive, among which a few were 20 times as large as some that remained. March 5th, I could see but three or four alive, and about the web I observed a black matter, about which the spiders had swarmed very much, and I found that it was nothing else but a heap of legs of those young spiders, whose bodies had been devoured.
On the whole, in this animal, which to some people is so odious, I have discovered as much perfection and hidden beauties as in any other ; for when I took the fleshy muscles out of their legs, and viewed them through the microscope, I was astonished at their transparency, and they seemed to be one body; but when I came to separate them, I found that they were composed of very long particles, each consisting of so many folds or wrinkles, that the muscle might be dilated or contracted, as occasion should require.
Concerning Trees found under Ground in Hatfield Chase.
By the Rev. Mr. ABRAHAM DE LA PRYME. - [1701.] The famous levels of Hatfield Chase, in Yorkshire, were the largest chase of red deer that King Charles the First had in all England: containing in all above 180,000 acres of land, about half of which was yearly drowned by vast quantities of water. This being sold to one Sir Cornelius Vermuiden, a Dutchman, he at length effectually dischased, drained, and