Nature's Teachings: Human Invention Anticipated by Nature. J. G. WoodЧитать онлайн книгу.
enemy should not penetrate. One mode of defence consists of a large net made of steel hanging loosely across it. The meshes are about ten inches square, so that the defenders can fire from their loopholes through the meshes, while the assailants, even if they knew of its position, would find that nothing smaller than a field-gun would have any effect on this formidable net.
The natural analogy of the fixed net is evidently the web of the common Garden Spider, or Cross Spider (Epeira diadema), whose beautiful nets we all must have admired, especially when we are wise enough to get up sufficiently early in the morning to see the webs with the dewdrops glittering on them.
Last year there was a wonderful sight. Within a mile of my house there is a long iron fence, which in one night had been covered with the webs of the garden spider. The following morning, though bright, was chilly, so that the dewdrops were untouched. I happened to pass by the fence soon after sunrise, and was greatly struck with the astonishing effects which could be produced with such simple materials as water and web. The dewdrops were set at regular intervals upon the web, so as to produce a definite and beautiful pattern, the whole line of fence looking as if it had been woven in fine lace.
Then, as the fence runs north and south, and the path is on the westward of it, every passenger saw the rays of the rising sun dart through these tiny globules, and convert every one of them into a jewel of ever-changing colours. It seemed a pity that such beauty could but last for an hour or so, or that these exquisite webs should only be used for catching flies.
Next comes the Casting-net in its various forms. This net is mostly circular, and is loaded round the edge with small leaden plummets. It is evident that, if such a net could be laid quite flat upon the water, it would assume a dome-like shape, in consequence of the circumference being heavier than the centre, and would sink to the bottom, enclosing anything which came within its scope.
The difficulty is to place the net in such a manner, and this is accomplished by throwing it in a very peculiar way. The net is gathered in folds upon the shoulder, which it partially envelops. By a sudden jerk the thrower causes it to fly open with a sort of spinning movement, and when well cast it will fall on the water perfectly flat.
After allowing it to sink to the bottom, the fisherman draws it very gently by a cord attached to its middle. As he raises it the weights of the leaded circumference are drawn nearer and nearer together by their own weight, and finally form it into a bag, within which are all the living creatures which it has enclosed.
Though the Casting-net has never been used in warfare, it was one of the favourite implements in gladiatorial combats among the Romans. Two men were opposed to each other; one, called the Retiarius or Netsman, being quite naked, except sometimes a slight covering round the waist, and armed with nothing but a Casting-net and a slight trident, which could not inflict a deadly wound. The other, called the Secutor or Follower, from his mode of fighting, was armed with a visored helmet, a broad metal belt, and armour for the legs and arms. He also carried a shield large enough to protect the upper part of the body, and a sword. It will be seen, therefore, how great was the power of the Casting-net, when it enabled its naked bearer to face such odds of offensive and defensive armour.
When the two met in combat, the Retiarius tried to fling his net over his adversary, and if he succeeded, the fate of the latter was sealed. Entangled in the loose meshes, he could scarcely move his limbs, while the sharp prongs of the long-shafted trident came darting in at every exposed point, and exhausting the man with pain and loss of blood. The trident was in itself so feeble a weapon, that if the Secutor were vanquished and condemned to death by the spectators, his antagonist could not kill him, but had to call another Secutor to act as executioner with his sword.
Should he fail in his cast, the Retiarius drew back his net by the central cord, and took to flight, followed by the Secutor, who tried to wound him before he could re-fold his net upon his shoulder, ready for another cast. It is worthy of notice that in these singular combats the netsman seems generally to have been the victor. A Retiarius with his net is shown in the illustration.
I may mention that our ordinary bird-catchers’ nets, and even the entomologist’s insect-net, are only modifications of the Casting-net.
Now for Nature’s Casting-nets, two examples of which are figured, though there are many more. These two have been selected because they are familiar to all naturalists.
The first is the Argus Star-fish, Basket-urchin, or Sea-basket. The innumerable rays and their subdivisions, amounting to some eighty thousand in number, act as the meshes of the net. All the rays are flexible and under control. When the creature wishes to catch any animal for prey, it throws its tentacles over it, just like the meshes of a net. It then draws the tips of the rays together, just as is done by the circumference of the casting-net, and so encloses its prey effectually.
The next specimen is the net-like apparatus of the common Acorn Barnacles, with which our marine rocks are nearly covered. These curious beings belong to the Crustacea, and the apparatus which is figured on page 89, and popularly called the “fan,” is, in fact, a combination of the legs and their appendages of bristles, &c. When the creature is living and covered with water, the fan is thrust out of the top of the shell, expanded as far as possible, swept through the water, closed, and then drawn back again. With these natural casting-nets the Barnacles feed themselves, for, being fixed to the rock, they could not in any other way supply themselves with food. There are many similar examples in Nature, but these will suffice.
The Rod and Line.
That both terrestrial and aquatic nets should have their parallels in Nature is clear enough to all who have ever seen a spider’s web, or watched the “fan” of the barnacle. But that the rod and baited line, as well as the net, should have existed in Nature long before man came on earth, is not so well known. Yet, as we shall presently see, not only is the bait represented in Nature, but even our inventions for “playing” a powerful fish are actually surpassed.
We will begin with the Bait.
In nearly all traps a bait of some kind is required, in order to attract the prey, and when we come from land to attract the dwellers in water to our hooks, it is needful that bait of some kind should be used, were it only to deceive the eye, though not the nostrils or palate, of the fish.
A notable example of the deception is given in the common artificial baits of the present day, which are made to imitate almost any British insect which a fish might be disposed to eat.
Perhaps the best instance of this deception is that which is practised by sundry Polynesian tribes. They have seen that the Coryphene or Dorado, and other similar fish, are in the habit of preying upon the flying-fish, and springing at them when they are tolerably high in the air. So these ingenious semi-savages dress up a hook made of bone, ormer-shell, and other materials, making the body of it into a rudely designed form of a fish. A hole is bored transversely through it at the shoulders, and a bunch of stiff fibres is inserted to represent the wings. Another bunch does duty for the tail.
The imitation bait being thus complete, it is hung to a long and slender bamboo rod, which projects well beyond the stern of a canoe, and is so arranged that the hook is about two feet or so from the surface. The Coryphene, seeing this object skimming along, takes it for a flying-fish, leaps at it, and is caught by the hook. There are in several collections specimens of these ingenious hooks, and I possess one which is made on similar principles, but intended for use in the water, and not in the air. It is, in fact, a “spoon-bait.”
One point of ingenuity must be mentioned, as it really belongs to the principle of the bait. These same savages, having noticed that