as accidental rather than according to the usual order of things; but there are several insects whose regular time of appearance is fixed by nature in the first months of the year, probably for the purpose of supplying a scanty meal to such of the soft-billed birds as are permanent residents, the berries on which they have in part subsisted being now useless or exhausted. Amongst these we may reckon the small egger-moth (Eriogaster lanestris), which is disclosed towards the end of February, having lain from the preceding July in a pupa case similar to plaster of Paris in consistence and appearance. The moth itself is but of middle size, and is pretty closely covered, particularly on the body, with hair. Its inconspicuous chocolate-brown colour might furnish the advocates for concealment in respect of colour with a very good illustration. The little gnat (Trichocera hiemalis, MEIGEN), which may be seen in troops during winter weaving eccentric dances in the air even when the ground is covered with snow, flies for shelter, as I have frequently found, to the hollow stems of umbelliferous plants and similar places near its usual haunts. A much smaller and more delicate fly, which has not a little puzzled systematic naturalists to class (Aleyrodes Chelidonii, LATREILLE), preserves itself from the cold in a similar manner. This species is so small, that it would not cover the area of a pin's head, and its snow white wings, as well as its elegant form, might entitle it to the appellation of the mite-butterfly; yet so well does this tiny creature know how to avoid cold, that, after the severe winter of 1829-30, I found three of them sporting about in March in Shooter's-hill Wood, as lively as if no frost had occurred. During the previous frost in that season, I opened two nests of the yellow ant (Formica flava), in which the inhabitants were by no means torpid or inactive, although not so lively as in summer; but these nests had been carefully constructed in a peculiarly warm situation, being both in the trunks of old willows, rendered quite spongy by dry-rot, and facing the southwest, where they had the benefit of every glimpse of sunshine. Ants, indeed, exhibit the most extraordinary tact in attending to variations of temperature, so much so, that they might, in a glazed formicary, constructed upon Huber's plan, be made to MAY, 1831. VOL. I. 2 M serve the purpose of a thermometer. Sir Edward King, an excellent naturalist, who lived in the time of King Charles II., seems to have been the first to discover this peculiarity :— 'I have observed,' says he, in summer, that in the morning they bring up those of their young, called ants-eggs (cocoons), towards the top of the bank, so that you may, from ten o'clock till five or six in the afternoon, find them near the top, for the most part on the south side. But towards seven or eight at night, if it be cool, or likely to rain, you may dig a foot deep before you can find them*. Ants, during winter, unquestionably manifest more intelligence, instinct, or whatever it may be termed, than bees; for the hive-bee will rashly venture abroad on the occurrence of a mild day, or even of a few hours' warm sunshine, when the ground is covered with snow; but I have never observed ants, either in the colonies naturally established, nor in the artificial formicaries that I have kept, tempted to venture abroad before the return of spring. The result is, that the bees (foolish in this instance, though wise in so many others) frequently perish from their rashness; while the ants are snug in their cells. This is the more surprising, that in the instance of swarming bees appear to be uniformly regulated by the temperature of the weather, and will not leave the original colony when the air is below a certain degree. While I was concluding this paragraph, I was, by accident, furnished with an example of the contrivances in question in a well known insect—the flea (Pulex irritans), which chanced to leap upon my paper, and, as I took care not to disturb it, I observed it attempting to dig a burrow with its beak. To this task, I have no doubt, it was sufficiently equal; but after working into the paper, so as to make a perceptible hole, it abandoned the spot, as if it did not like the material. After skipping about for some time, it settled on the green cloth cover of my desk, where it again made an attempt to burrow; and I remarked that, in this case, contrary to its mode of working on the paper, it threw itself on its back, pushing the wool upwards with its feet, and downwards with its shoulders, Phil. Trans. No. xxiii. P. 425-7. till it wedged itself into the nap quite out of sight, intending of course to lie snug and warm till hunger should prompt it upon a foraging excursion. I am well aware that observations like this have drawn forth the ridicule of witlings, who have represented naturalists as little better than children or idiots; but, if the Great Creator did not think it beneath him to adapt, with wonderful skill, the structure of a flea to its mode of life, it can never be a trifling study to observe and admire such instances of his providential wisdom. Many other illustrations of the attention of animals to secure warmth crowd upon my recollection; but, as this paper may already be deemed too tedious, I shall, for the present, forbear go into further detail. to Lee, Kent, March 7th, 1831. ON THE AURORA BOREALIS OF THE 7th OF BY DR. MOLL, OF UTRECHT. FOR many years the beautiful phenomenon of the Aurora Borealis has been of very rare occurrence in this country; so much so, indeed, that I do not recollect having seen it more than once, and that was in 1828, and even then it was in England. During the time of the late Professor Van Swinden's residence in the University of Franeker, between 1766 and 1784, particularly in 1769, 1772, 1773, and 1777, it was very frequently witnessed by that diligent and accurate observer, and his observations are well known to the scientific world. Since that period, it scarcely ever shone in all its splendour; and now and then only its existence in more northern regions has been announced to us by some faint coruscations near the boreal part of the horizon. On the 7th of January last a beautiful exhibition of this phenomenon was witnessed here between 6 and 10 P.M., the effect of which was particularly striking. The sky was very clear and transparent; the stars were remarkably bright; Cassiopea nearly in the zenith; Orion ascending in all its glory towards the meridian; Procyon standing in the east, whilst Lyra and the Swan descended towards the horizon in the N.W. The air was very calm: after some days of thaw the weather had become frosty. The thermometer, during the time of the phenomenon, ranging between 26° and 24° Fahr. The little breeze there was blew from the S.E. From the S.W. to the N.E. a bright arch of whitish light extended itself through the firmament, its width being about 10° or 12°. This luminous arch passed through the zenith, a little to the northward of the Pleïades. Its light was of a white colour, and uniform throughout. Shortly after, a second similar arch sprang up to the north side of the first. From the S.W. to the N.E. a column of light arose in an oblique direction; a similar one formed in the zenith; these three columns joining together, and thus a double arch of unparalleled beauty illuminated the heavens, whose continual coruscations formed a most extraordinary spectacle. To the south of this arch, in that part of the sky where Orion then was, and somewhat lower than y and a of that constellation, and near the Eagle and Dolphin, the firmament was of a dark blue; and Orion, glittering on this dark ground, shone in beautiful contrast with the vivid light of the luminous arch. The appearance of this arch or luminous belt lasted only a few minutes: it began first to fade in that part of the air whence it arose in the beginning. In the N.W. the air was illuminated as if by the crepuscule of a summer's night. Being then in the country, I hastened to an open field, where the view of the horizon in the north was not impeded by buildings. There, in the north, that luminous circular arch, which is so frequently mentioned by writers on the Aurora Borealis, was splendidly visible. I would rather call it a segment of a circle, of which the horizon was the chord. The bright star a Lyra was nearly in the middle of this segment, and it extended as far northward as the tail of Ursa Major. Under this luminous arch the sky was somewhat blacker; but I did not observe under it that dark part which frequently occurs in descriptions of the Aurora Borealis. From out of this luminous arch, as if from its centre, rays of tremulous white light were incessantly springing up in all directions; of these rays have been often (not unjustly) compared to the sticks of a fan. Sometimes these rays ascended nearly as high as the zenith, then disappeared, and were succeeded by others. The space between the columns was frequently of a beautiful rosecolour. In about half an hour the flame-like rays ceased to rise from the luminous segment in the N.W.; but the segment still continued to shine with a softer light. At about nine o'clock the beautiful appearance called by authors on the Aurora, the Pavilion, was displayed. From the zenith, large and bright streams of flame-like light descended towards the S.W., N.E., N. and N.W. in splendid succession; and the view they afforded was sublime and magnificent beyond description. The N.W. part of the firmament was now covered with coruscations of glowing red light, continually varying in appearance. The brown heath on which I walked was so illuminated as to make objects appear perfectly distinct, even at some distance. During the vivid and sudden changes of these luminous flashes, a single mass of light, like a cloud, arose from the N.E. towards the zenith, passing in quick motion very near the Pleïades, and disappearing in the S.E. This orb of light, through which the stars were visible, was round and globulous in the fore-part, and terminated in a flaming, tapering tail. Its appearance was short and very striking. It was a glorious illustration of the truth of Lucan's description: Ignota viderunt obscuræ sidera noctes; Ardentemque polum flammis; cœloque volantes The phenomenon disappeared gradually; the Pavilion lasted but a short time: at about ten o'clock the luminous arch alone remained visible in the N.W.; this continued during several hours, till the wonted darkness of night was entirely restored. The next day the weather was thawing and snowy, the wind S.E. The sky, however, seemed in the night following somewhat brighter in the N.W. The following is the abstract of the barometric and thermometric observations some days before and after the Aurora Borealis. |