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The Naturalist's Diary
For NOVEMBER 1829.
Dark-featured Autumn, and their waking might,
Rends the first pale leaves in their stormy flight:
The eyes meet sadness wheresóe'er they light;
Cast o'er the valleys; the far mountaiu's height
Honill's Forest Minstrel.
ALTHOUGH November is usually dull and cheerless, yet there are some intervals of clear and pleasant weather. The fields and inclosures are cleared of their harvest treasure, and the web of the gossamer extends in unbroken and floating pathway over stubble and lea. This gossamer appearance, upon which so many speculative opinions have been formed, is now considered to be produced by the ascent of the spider into the atmosphere. Mr. Murray, in his . Researches into Natural History,' has given particular attention to this curious subject, and the following is the result of his observations:
About the beginning of the last century, gossamer was supposed to be condensed vapour. Geoffroy gave it as his opinion, that it was a web spun by the acarus telarius, on the north side
of trees; and being from thence dispersed by the wind, covers the fields with those innumerable threads. It is now known to be produced by many different kinds of spiders, particularly the flying spiders. Mr. Murray assures us, that they have actually the power of projecting their threads to a considerable distance, and by such means transporting themselves from the ground to any elevation, or from the top of one elevation to another. But, what is still more astonishing, he conceives that these threads are electric, or so actuated by that subtle element, that buoyancy is imparted, and the baseless shrouds of the aërial traveller are, with itself, projected aloft into the highest regions of the air! There are but very few spiders which, in crawling over uneven surfaces, do not leave behind them a thread, serving as a cable, or rather a line of suspension, lest they should fall, or be blown off from any eminence; consequently, the whole surface of the ground, throughout the summer months, is covered with their network; not only with webs of the ground spider, which may be called personal property, but from innumerable threads of vagabonds. This accumulation creates no wonder, because it is certain that these threads, however delicate, are at the same time durable. But that this tissue is constantly increasing, may be seen by following the plough for a short space; for no sooner bas the team finished one land or ridge, but the fresh ground is quickly interlaced with threads, which glisten in the sunbeam. There is no accounting for this, except on the facts stated by the author, viz. that the air in fine weather is filled with
the excursive threads of the impennous aranea æronautica. The insect is often detected at the end of its thread, with its little arms extended, and balancing itself like a bird, and always proceeding before the wind. This direction of their flight always accounted for the connection between tree and tree, or hedge and hedge ; moreover, the insect, by its instinctive sagacity, in committing a coil of its thread to the wind, and taking its chance of a distant attachment, could then transport itself in safety. But the author has seen threads projected or propelled in a close room, where there could be no current of air to carry the same in any direct line; and so far the relation is most interesting.-Magazine of Natural History.
The water-ouzel, or water-crake, frequents small brooks, particularly those which intersect rocky countries. It forms its nest in the holes of banks ; and lays five eggs of a whitish colour, adorned with a fine blush of red. It feeds on small fish and insects; and though its feet are destitute of webs, and the whole form of its body denotes it to be a land
fowl, it nevertheless darts itself quite under the water in search of fish. Its nest is very curiously constructed of hay and the fibres of roots, and lined with oak-leaves.
In this month, or in October, according to the time when the cold autumnal rains commence, the larger eels migrate towards the sea. Sir Humphrey Davy, in his Salmonia, says
This is certain, that there are two migrations of eels—one up and one dowa rivers, one from and the other to the sea; tbe first in spring and summer, the second in autumn or early winter: the first of very small eels, which are sometimes not more than two or two and a half inches long; the second of large eels, which sometimes are three or four feet long, and which weigh from ten to fifteen, or even twenty pounds. There is great reason to suppose that all eels found in fresh water are the results of the first migration; they appear in millions in April and May, and sometimes cortinue to rise as late even as July and the beginning of August This was the case in Ireland in 1823. It bad been a cold, backward summer; and wben I was at Ballyshannon, about the end of July, the mouth of the river, which had been in flood all this month, under the fall, was blackened by millions of little eels, about as long as the finger, which were constantly urging their way up the moist rocks by the side of the fall. Thousands died, but their bodies remaining moist, served as the ladder for others to make their way; and I saw some ascending even perpendi. cular stones, making their road through wet moss, or adhering to some eels that had died in the attempt. Such is the energy of these little animals, that they continue to find their way, in im
mense numbers, to Loch Erne. The same thing bappens at the fall of the Bann, and Loch Neagh is thus peopled by them; even the mighty Fall of Schaffhausen does not prevent them from making their way to the Lake of Constance, where I have seen many very large eels. There are eels in the Lake of Neufchatel, which communicates by a stream with the Rbine; but there are none in the Lake of Geneva, because the Rhone makes a subterraneous fall below Geneva; and tbougb small eets can pass by moss or mount rocks, they cannot penetrate limestone rocks, or move against a rapid, descending corrent of water, passing, as it were, through a pipe. Again: no eels mount the Danube from the Black Sea; and there are none found in the great extent of lakes, swamps, and rivers communicating with the Danube, though some of these lakes and morasses are wonderfully fitted for them, and though they are found abondantly in the same countries, in lakes and rivers connected with the ocean and the Mediterranean. Yet, when brought into confined water in the Danube, they fatten and thrive there. As to the instinct which leads young eels to seek fresh water, it is difficult to reason; probably they prefer warmth, and, swimming at the surface in the early summer, find the lighter water warmer, and likewise containing more insects, and so pursue the courses of fresh water, as the waters from the land, at this season, become warmer than those from the sea. Mr. J, Couch, in the Linnean Transactions, says the little eels, according to his observation, are produced within reach of the tide, and climb round falls to reach fresh water from the sea. I have sometimes seen them, in spring, swimming in immense shoals in the Atlantic, in Mount Bay, making their way to the mouths of small brooks and rivers. When the cold water from the automnal flood begins to swell the rivers, this fish tries to return to the sea; but numbers of the smaller ones hide themselves during the winter in the mud, and many of them form, as it were, masses together. Various authors have recorded the migration of eels in a singular way; such as Dr. Plot, who, in his History of Staffordshire, says they pass in the night across meadows from one pond to another; and Mr. Arderon, in the Philosophical Transactions, gives a distinct account of small eels rising up the flood-gates and posts of the water-works of the city of Norwich; and they made their way to the water above, though the boards were smooth planed, and five or six feet perpendicular. He says, when they first rose out of the water upon the dry board, they rested a little-which seemed to be till their slime was thrown out, and sufficiently glutinous and tben tbey rose up the perpendicular ascent with the same facility as if they had been moving on a plane surface. There can be no doubt that they are assisted by their small scales, wbich, placed like those of serpents, must facilitate their progressive motion : these scales have been microscopically observed by Lewenhoeck.
Eels migrate from the salt water of different sizes, never when they are above a foot long, and the great mass of them are only from two and a half to four inches. They feed, grow, and fatten in fresh water. In small rivers they seldom become very large; but in large deep lakes they become as thick as a man's arm, or even leg; and all those of a considerable size attempt to retarn to the sea in October or November, probably when they experience the cold of the first autumnal rains. Those that are not of the largest size pass the winter in the deepest parts of the mud of rivers and lakes, and do not seem to eat much, and remain almost torpid. Their increase is not certainly known in any given time, but must depend upon the quantity of their food: it is probable they do not become of the largest size from the smallest, in one or even two seasons; but this, as well as many other particulars, can only be ascertained by new observations and experiments. Bloch states, that they grow slowly, and mentions that some had been kept in the same pond for fifteen years. As very large eels, after having migrated, never return to the river again, they must (for it cannot be supposed that they all die immediately in the sea) remain in salt water; and there is great probability that they are then confounded with the conger, which is found from a few ounces to one hundred pounds in weight.
The bright-eyed Perch, with fins of Tyrian dye. The Perch, when upwards of a pound weight, is a fine looking fish, and its flesh is reckoned firm and nutritious, being excelled by none of the fresh-water tribe. Perch delight to lie about bridges and millpools, in and near locks; about shipping, barge and floats of timber in navigable rivers and canalss; and at the entrance, and in wet docks; also in deep