DESCRIPTION of a GLORY; by JOHN HAYGARTH, M. B. F. R. S. Lond. F. R. S. and R, M. S. Edinb. and Fellow of the American Academy of Arts and Sciences. Communicated by Dr. Percival.

READ MARCH 13, 1789.

N the thirteenth of February 1780, as I was returning to Chefter, and afcending, at Rhalt, the mountain, which forms the eastern boundary of the Vale of Clwyd, I observed a rare and curious phænomenon. My ingenious friend Mr. Falconer, has given, from my description, an exact representation of it, in a drawing which accompanies this paper. (See plate IV.)

In the road above me, I was ftruck with the peculiar appearance of a very white shining cloud, that lay remarkably close to the ground. The fun was nearly fetting, but fhone extremely bright. I walked up to the cloud, and my shadow was projected into it; when, a very unexpected, and beautiful scene was presented to my view. The head of my fhadow (fee plate IV.) was furrounded, at fome diftance, by a circle of various colours, whofe centre appeared to be near the fituation of the eye, and whofe circumference

cumference extended to the fhoulders. The circle was complete, except what the fhadow of my body intercepted. It exhibited the most vivid colours, red being outermoft: as far as can be recollected, all the colours appeared in the fame order and proportion that the rain-bow prefents to our view. It refembled, very exactly, what in pictures is termed a glory, around the head of our Saviour, and of faints: not indeed that luminous radiance, which is painted clofe to the head, but an arch of concentric colours, which is placed feparate and diftinct from it. As I walked forward, this glory approached or retired, just as the inequality of the ground fhortened or lengthened my fhadow. The cloud being fometimes in a fall valley below me, fometimes on the fame level, or on higher ground, the variation of the fhadow, and glory became extremely striking and fingular.

To add to the beauty of the scene, there appeared, at a confiderable diftance, to the right and left, the arches of a white fhining bow. Thefe arches were in the form of, and broader than a rain-bow: but were not completely joined into a femicircle above, on account of the shallowness of the cloud. When my chaife came up, I could obferve no peculiar appearance round the fhadows of the poftillion, horfes, or chaife. But the poftillion was alarmed, to an uncommon degree, by this very fingular appari

tion: which indeed, might excite terror, or delight, in the beholder, according to the difpofition of mind with which it was viewed.

Several appearances have been described by philofophers, in fome refpects resembling what I faw, but not exactly the fame. The arch in fize, fituation and colour was most exactly the glory reprefented in fome pictures, and is manifeftly the archetype whence it has been copied by a painter. Indeed fuch a phænomenon is well adapted to excite religious awe and reve

rence.

When I returned into the chaife, a bright radiance appeared close to its fhadow, but no feparate coloured circle was formed.

In order to investigate the cause of these curious appearances, on optical principles, it may be useful to note fome peculiar circumftances. The cloud was fpecifically heavier than the air of that region where it was placed: for, it defcended, with confiderable velocity, down the fide of the mountain. It was very close and fhallow, being, in part, compreffed by its own weight, the air at that altitude being too rare to fufpend it.

I have seen, at other times, but not frequently, clouds of the fame appearance. On the 28th of November 1780, I faw fome clouds which exactly resembled thofe in which the glory was obferved, but had not leifure to approach them. VOL. III. Hh These