motive power has not ceased to the apparatus attached to the

seeds when this has twisted itself

into this balloon shape; the slightest hygrometric change produces motion, either backwards or forwards, in the awn; and the constant tendency of this motion is to screw the seed into the ground. Such is the shape and great sensibility of the awns, that they may be readily applied to form most delicate differential hygrometers, for which purpose I have used them.

The arrangement of the seeds of the Pelargonium peltàtum is almost identical with the above, but less marked.

The extreme beauty of the contrivance, thus attempted to be described, can hardly be appreciated without examination of the

plant itself; for which object, as well as for its appearance as a border plant [and the high musky odour of its herbage], it is worthy of cultivation.

It seems to me that no part of the organisation of plants is so well worthy of attentive examination as the contrivances for effecting the dispersion of the seeds: these in all cases show the benevolent provisions of the Creator, that vegetable food may be spread abroad, and increase, and that the earth may be full. Each solitary contrivance of dispersion strikes the mind as above human invention, and as defying human imitation; but when we wander from one to another, and see their almost infinite variety, admiration of individual contrivance is lost in the plenitude, the apparent wantonness of immeasurable design, every where different, and every where perfect.

Capel Street, Dublin.

ART. VII. Particulars on Appearances of Instances of Aurora Borealis at High Wycombe, Bucks, on Nov. 18-19. 1835, Jan. 7. 1831, Sept. 9. 1835, and Sept. 13. 1835. By JAMES G. TATEM, Esq.

THE aurora borealis which was observed last night, November 18-19. 1835, was too splendid, and too extensively seen,

not to claim the attention of the correspondents of your Magazine. Allow me, therefore, to state the appearances at this place, in the hope that others, better qualified than myself, may add to the report of their observations their thoughts on the origin or cause of this beautiful and interesting kind of phenomenon.

At 9 P.M. the aurora was first seen by me, although some indications had been noticed more than an hour before. At this time the whole sky, from the N.E. point of the horizon to the s.w., was highly illuminated: at the base was a brilliant elliptic arch of bright yellow; above which, at some distance, was a second luminous arch, surrounded, at the apex and for some distance on each side, with points, those nearest the centre forming isosceles triangles: the space below the first arch was of a ferruginous purple colour, while that which separated the two arches assumed a brighter blue tint, approaching nearer to the general colour of the sky at night. From these arches frequently emanated long streams of light, some of a bright red, and others of a greyish blue, colour, which extended considerably to the southward of the zenith; at times the whole body of light was much increased, as if a discharge had taken place, when streams like to those before-mentioned were ejected, and coruscations, having the appearance of tidal waves flowing on a level shore, were noticed. These flickered in an extraordinary manner, and their undulations were extremely rapid as they passed off into the distance. By 10 P.M. the rays and coruscations had ceased, and the lower arch of silvery light alone remained; but about 11 o'clock the grey rays were again ejected, but did not continue for any length of time; from this hour, until 5 o'clock the following morning, the north-western quarter of the heavens was illuminated by a silvery light, like that of the rising moon, rendering distant objects distinctly visible. What most excited my surprise is, that, at the time the aurora was brightest, a few streams of red light seemed to cross those issuing from the arches almost at right angles. A fresh breeze blew from the westward during the time; the barometer rose a little, and the thermometer, which stood at 41° 50' at 10 P.M., fell to 35° 25′ in the night; some rain fell on the night of the 19th. The accompanying sketch shows the appearance about half-past 9 o'clock (fig. 12.)

The appearance of aurora borealis above noticed was by much the most splendid one that has been seen at Wycombe during my residence at it (nearly thirteen years). The other instances in which they have been deserving of particular attention occurred on January 7. 1831, and on September 9.

and 13. 1835: the following is a copy of my notes on these, made at the time:

January 7. 1831.-The most splendid aurora borealis that has been seen in these parts for the last thirty years, was observed this evening. About 7 o'clock, the whole atmosphere from the E.N.E. to the N. was brilliantly illuminated by a deep yellow light; from the first-mentioned point several curved

and divergent rays issued; at intervals streams of a greyishblue light shot up with great velocity, and, passing the zenith, vanished in a few seconds; these appearances continued for nearly an hour, when the radii assumed a deep red tint, and the whole light spread further to the westward; at one time two red rays took the shape of a very pointed arch, like that of a lancet window; with little variation as to form and brightness, the rays continued, until past 9 o'clock, still extending more to the westward, and reaching from the E.N.E. to the

W.S.W. After this hour the aurora gradually became fainter, but had not entirely disappeared until after midnight.

September 9. 1835.-This evening the most brilliant aurora borealis that has appeared here since January 7., 1831, was observed. The whole north-western quarter of the heavens was illuminated by a pale yellowish light, from which rays of nearly the same colour shot forth, and extended beyond the zenith these appearances continued for nearly the space of two hours.

September 13. 1835.-The aurora was again visible this evening, when the rays were of a red tint, and rose nearly to the zenith; but were not so bright, and did not continue so long, as on the 9th. The wind, on both occasions, blew fresh from the westward, and these phenomena were succeeded by rain.

It may be well to notice, that the wind blew from the westward when the aurora of January 7., 1831, was visible; that the barometer was very high, and that the thermometer fell fifteen degrees below the freezing point during the night, but afterwards gradually rose; and that rain fell on the night of January 9.

Wycombe, November 19. 1835.

ART. VIII. Particulars on Appearances of Instances of Aurora Borealis at Swanswick, near Bath, on Nov. 17-18, 18. 1835. By

THE beautiful phenomena of the aurora borealis having been displayed, with unusual splendour, on the evening of November 18., and, in various parts of the country, excited more than ordinary attention, it may be interesting to some of your readers to record the following memoranda of their appearance; and these may, by affording means of comparison with the observations of more scientific individuals in other and distant parts of the country, be useful in a meteorological view.

The aurora borealis had been marked on the night of the 17th, and early in the morning of the 18th. The prevalence, however, of an almost uniform stratum of cloud prevented, at the time of my observation, any other appearance than that of considerably diffused and reddish light along the northern horizon. About 1 A.M., this light was equal in intensity to strong moonlight in a clouded night.

On the evening of the 18th, circumstances were highly favourable for observation. Soon after sunset, considerable light was seen to be diffused along the northern horizon, assuming, about 8 P.M., the appearance of a broad and ill-defined bank

of hazy light. From a quarter before nine, till a quarter past nine P.M., the phenomena were of the most striking description. A broad, elliptical, but ill-defined, arc of light extended from about E. by N. to w. by N. The altitude of the centre of this arc of light, which, at a quarter before nine, P.M., was about 30°, became gradually less; the arc itself finally, as it were, dissolving, and leaving only a general and faint light along the horizon. Meanwhile, however, streams of light, varying in intensity and breadth, were sent up from different parts of the arc, at irregular intervals, towards, and reaching, the zenith; sometimes appearing stationary; at others, visibly moving with great velocity. But the most remarkable feature of the phenomenon was the rapidity and intensity of the coruscations, often thrown up simultaneously from almost all parts of the arc of light, and producing an effect somewhat similar to the consecutive and concentric waves on a pond after throwing in a stone: there were certain parts of the heavens in which these waves of light were usually much more brilliant than in others. These coruscations were very similar in appearance to those in the imitative-aurora electrical experiment in the exhausted flask; and they followed, often, so rapidly, and in masses of such breadth, as to have somewhat the effect of immense clouds of luminous striated smoke.

The arc of light, when first observed, about a quarter before nine P.M., passed across the stars a and 6 (the pointers) in Ursa Major. The principal stars in that constellation were visible through the luminous arc, but somewhat feebly. About the zenith, and extending eastward as far as the Pleiades, the clouds of luminous matter darted sometimes from E. by s. towards the N., and sometimes from E. to w. A considerable breadth of the heavens between the N.w. and the w. was overspread with a dull red light. About nine P.M. a bright meteor, or falling star, was observed; it appeared about the middle of the constellation Camelopardus; its direction was opposite to that of the auroral coruscations, darting towards the N.E. point of the horizon; and its train visible, probably about 10° or 15°.

The barometer, which, at the place of observation, stood, on the 13th, at 29.86, had gradually sunk, at nine A.M. on the 18th, to 29-49, but at ten P.M. had risen again to 29.52.

The minimum temperature of several preceding days had varied from 30° to 36° Fahr.; but in the night, between the 17th and 18th, had not been lower than 42°.

The wind had gradually veered from N. on the 15th, to N. by w. on the 16th, and w. by N. on the 17th, to w. on the 18th, and blew steadily, and rather briskly, during the whole