Графични страници
PDF файл

Possessed of materials so numerous and important, it must have required a powerful effort to resist the temptation of forming a system. Saussure, however, had this firmness of resolution; and we shall make it the last and the principal trait in his eulogy. His mind was of too elevated a character not to take a prospective grasp, in some measure, of the whole field of the science, and not to perceive to what extent it was imperfect, notwithstanding all the facts with which he had enriched it; and it was, therefore, by pointing out what still remained to be investigated that he terminated his labours. So noble an example has not deterred his successors from drawing up, as formerly, the most romantic systems; but this is only an additional reason for paying our tribute to a mind so rare.

Saussure still seemed young enough to collect a portion of the observations which were awanting to the science ; but a disease, the germ of which had perhaps originated in the fatigues of his journeys, began, a little after his fiftieth year, to undermine his constitution. It was increased by some embarrassments of fortune, occasioned by the French revolution. Three successive attacks of paralysis reduced him to great weakness, and, on the 22d January 1799, after four years of sufferings, he died, aged only 59 years.

Equally beloved and honoured as Bonnet by his fellow citi zens and by strangers, Saussure had the additional happiness of living again in a son, whom he saw distinguishing himself in science, and whose beautiful discoveries have merited for him a reputation not less honourable than that of his father; and in a daughter, whose rare virtues and superior mind have rendered her an ornament to her sex.

A Description of some appearances of remarkable Rainbows.

By the Reverend WILLIAM SCORESBY, F. R. S. Lond. and Edin. M. W. S., &c. Communicated by the Author. (With

a Plate.)* APPEARANCES of natural phenomena, of rare occurrence, are always worthy of being recorded, both as being interesting to the

* Read before the Wernerian Natural History Society 10th February 1827.

observer of nature, and as tending to the development of those beautiful principles with which the Almighty has so universally endued the vast range, and every atom of that yast range of the material creation. And they are further interesting, because, when understood, they generally resolve themselves into the effects of some laws, principles, or combinations already known, and afford additional instances of their amazing variety of operations, and of their universality of application. In this view, therefore, even modifications of the more ordinary phenomena, or extreme cases as to beauty, extent, or peculiarity of such, are not undeserving of attention, either to the naturalist or the philosopher.

Hence I am induced to offer to the Wernerian Society an account of two appearances of rainbows—though a phenomenon of such ordinary occurrence; because, in one of these cases, there was exhibited perhaps the extreme of beauty of which this brilliant arch is susceptible ; and, in the other case, there was a multiplication of the segments beyond any other example of a rainbow I ever before witnessed.

The first example that I shall mention, so nearly resembled a remarkable rainbow described in a late number of the Edinburgh Philosophical Journal (a rainbow that appeared at Lengsfeldt, on the 18th of May last), that I fear the following description will seem to be little else than a repetition of what is already before the public. At all events, presuming on the interest which observers of nature always feel in such appearances as are at all of an extraordinary character, I shall not withhold the notes which I made on the occasion.

This magnificent phenomenon was seen at Bridlington Quay at 5 P. M. of the 12th of August 1826, during a brilliant sunshine, and a heavy partial shower that passed across from north to south, to the eastward of the town. Both the primary and secondary bows were complete arches, descending to the ground on the left, and to the surface of the sea on the right hand. The colours were of extraordinary brilliancy throughout. Within the arch of the primary bow, were no less than three if not four supernumerary bows in close and regular order, but

pro gressively diminishing in intensity, so that the last was scarcely discernible. The primary bow was of course a series consisting

[merged small][merged small][merged small][graphic][ocr errors][merged small][merged small][merged small][merged small][merged small]

of the ordinary succession of colours, reckoned from the outside, being red, orange, yellow, green, blue, indigo, and violet. Immediately in contact with the interior violet, succeeded the

supernumerary stripes of different colours, consisting, most obviously, of green and purple or violet, in regular succession. The other colours of the spectrum were not observed. The whole phenomenon conveyed the idea of a splendid canopy of equal vertical arches, which seen from beneath, seemed to diminish in distinctness from the effect of the receding distance.

Another phenomenon of the same class, with a peculiarity which appeared to me to be of a very uncommon kind, may be of more importance to be described.

This consisted of two beautiful segments of primary and secondary rainbows, (called by the sailors “ weather-galls,” when, as in this case, they consist only of the portions next the horizon) with some supernumerary bows within the arch of the former ; and likewise, which is the extraordinary part, another spectrum rising almost vertically from the base of each of the common arcs, at its apparent termination in the horizon of the sea, so as to form two figures nearly resembling the Greek y.

The segments a and b, Fig. 1. Pl. IV. represent the portions of the primary and secondary bows, and e the supernumerary bows, whilst c and d represent the two vertical spectra. Perhaps I err in defining them vertical spectra, because the apparent form was a portion of a circle, curved in the same direction (namely, towards the left) as the irides; but not having used any means to ascertain the exact form, I cannot speak with certainty, either as to the curvature, or to the direction in which it deviated, if it deviated at all, from the perpendicular. In other respects, there is no uncertainty, not even as regards the apparent form, a sketch of the appearance being carefully made at the time.

The colours of the primary vertical spectrum (c) were in the same order, and almost of similar brilliancy, as the rainbow with which it was connected ; and the colour of the secondary vertical spectrum (d), as well as its width and general appearance, also corresponded with the colours and magnitude of its own bow.

This phenomenon was seen on the 3d of September 1821, at

« ПредишнаНапред »