secret charm, I grant you, in all these, and an undefinable sensation of pleasurable feelings in our minds respecting them, which I believe to be instinctive, is excited by their view; but still they are like the pictures in the gallery, they please the eye, we like them, and there, generally, the matter ends. But let me recommend to you to enquire, to put questions, to find out sources of information respecting them. Along with the portrait, get a knowledge of their character and history. Make use of some system of classification, and learn to refer any animal, plant, or mineral you meet with, to its class, order, genus, and species. You will find good instructions on this head in the first volume of Withering's Arrangement of British Plants, so far as relates to botany; but analogous methods are used in the other kingdoms of nature. When the scientific name has been gained, you have a key to the whole history of the species, so far as is known. The synonymes, or references in the system you make use of, will refer you to the authors who have written upon or figured the species you are investigating; and thus you may become intimate with the animals, plants, and minerals you meet with, if you choose to take the trouble, or rather I would say the pleasure, of doing so.

I mean not to insinuate, however, that a systematic knowledge of things is absolutely necessary to enable us to enjoy the productions of nature in a very high degree. On the contrary, I hesitate not to assert that any man, though he be but slightly or not at all versed in science or scientific names and distinctions, may, if he choose, never be at a loss for subjects of exalted and delightful reflection. Let him but look around him, and think of the objects he beholds, and in his thoughts never lose sight of the great and inspiring truth that they are the works of the Deity. If a man in this tone of mind explore the banks of a lake or river, has he not in himself a store of solid occupation much superior to that of throwing an artificial fly or torturing a worm upon a hook? If he sketch the scenery before him, or examine an insect, or dissect a flower, not as things that have come there he knows not why nor wherefore, but as examples of the exquisite workmanship of God, -as objects which were worthy of the attention of him, else he would not have made them, and therefore must be worthy of the admiration of us, who have the inestimable privilege of seeing him in his works; that man, I insist, has in himself sources of pleasure infinitely superior to

what are commonly called rural sports. In the latter, too, I must observe that the objects are very limited; while the stores of amusement and of true information to be found in the pursuit of natural history are inexhaustible, never ending, and at the same time ever new.

43

LETTER IV.

BEFORE proceeding farther on our excursion, let me detain you a little by observing that persons used to angling are well acquainted with one sort of bait which the trout is particularly fond of, and which I suppose you have yourself often remarked, I mean the caddis, or cadew worm, called also the straw-worm, or cad-bait, or caseworm. It is common in streamlets and ditches of clear water; but before calling your attention more particularly to it, I may remind you of the metamorphosis of insects by saying a few words on the common butterfly (Papilio brassica). This species deposits her eggs towards the end of May, and invariably on the cabbage. Now this is worthy your attention ;-were the eggs laid on a lettuce, or a rose bush, or a celery plant, or a leek, or any of the other vegetables in the garden, they would not succeed, because it has been ordered that the young which escape from them can only live on the cabbage. The parent butterfly, as if aware of this, never makes

species of plant; but still there is something more required than this. Suppose she placed them on the upper or exposed surface of the leaf, what would be the consequence? They might be shrivelled up by the heat of the sun, or injured by the rain; but what is much more certain, the young, when hatched, would be exposed to the view of the small birds which prey greedily upon them, and hence they would mostly fall victims, and that at a period when from their small size their acquisition could be comparatively of trifling service to the bird. The parent butterfly always attaches them to the under, never to the upper surface of the leaf. It is also said, that if she find the cabbage preoccupied by the progeny of another butterfly, she will reject it, and seek out one as yet untouched, else the two broods might not have sufficient protection and food.

Nor is the mode of attachment of the egg to the leaf a random operation, but the very reverse. The young, when hatched, are to come out of one end, and the eggs, as is the case with those of many other insects, are placed vertically on one end, and disposed side by side, "so as,' Mr. Kirby observes, "comparing small things with great, to resemble a close column of soldiers." In a few days the young creep out of