President.

JOSEPH BROOKS YATES, ESQ., F.S.A., M.R.G.S., M.P.S.

Vice-Presidents.

JOSEPH DICKINSON, M.A., M.D., M.R.I.A., F.L.S., F.B.S.E. ROBERT M'AN. REW, F.L.S. WILLIAM H. DUNCAN, M.D.

The PRESIDENT briefly explained the Proceedings of the Committee appointed to investigate the Pendulum experiment,* when

It was moved by Mr. J. P. G. SMITH, and seconded by JOSEPH DICKENSON, M.D.

"That the thanks of the Literary and Philosophical Society are eminently due, and be conveyed, to JOHN THOMAS TOWSON, Esq., for the kindness with which he explained the theory of the Azimuthal Motion of the Pendulum, to the persons who visited the Sailors' Home during the performance of the experiment, for which purpose he gave up, gratuitously, a large portion of his valuable time."-Carried unanimously.

Moved by Mr. HEATH, seconded by the Rev. H. H. HIGGINS—

66

That the thanks of the Society be given to DAVID PURDIE THOMSON, M.D., for his valuable services as Secretary during the past year, and especially for the able manner in which he has edited the Transactions of the Society for the two last sessions."-Carried unanimously.

*Vol. 6, page 238.

ROYAL INSTITUTION.-November 3, 1851.

J. B. YATES, Esq., F.S.A., &c., PRESIDENT, in the chair.

Mr. EDWARD HEBSON was elected an Ordinary Member.

The President read the following Letter from GEORGE WILLIAMS, Esq.,

ON THE TOTAL SOLAR ECLIPSE OF JULY 28, 1851. On the 19th of July, 1851, I sailed from Hull in the company of Mr. Lassell and Mr. Stanistreet, and touching at Christiania, we arrived at Gothenborg, in Sweden, on the 24th, from whence we proceeded to Trollhatten, the place from which we had decided to view the eclipse.

The time prior to the day of the eclipse was occupied in preparing our instruments; selecting a neighbouring eminence for the observations, taking altitudes for time, and inspecting the magnificent waterfall. The sky for many days had been overcast, and much rain had fallen. On the morning of the 28th (the day of the eclipse) the heavens appeared covered with one impenetrable stratum of clouds, and the wind became so high, that we at once abandoned the idea of setting up the instruments in the open air, and determined to make our observations from the windows of our rooms, which fortunately commanded a considerable extent of view, ranging from about N.E. by S. to N.

As the day advanced we watched the aspect of the sky with intense anxiety. A little before noon the clouds began to break, occasional gleams of sunshine appeared, these increased in duration, until at length the sun shone forth in full splendour. On Plate I., Fig. 1, are sketched the maculæ, a. b., then visible on the sun's disc.

The heat of the sun now became intense, the two dark glasses which I had been in the habit of using for the last five years, gave way and cracked. My friends also lost several sun glasses, we were therefore deprived of the use of these when they were most needed. The intensity of the calorific rays may possibly be due to the clear and highly transparent atmosphere of Sweden, rather than to a variation in the component parts of the spectrum, but of this I am unable to give a further opinion.

My telescope had an aperture of 2 inches, with a 42-inch focus, and

a micrometer in the eye-piece for taking rapid approximate measure

ments.

At about 2h. 45m. p.m. local mean time, the telescopes were placed in position, and at 2h. 53m. 48s. local mean time, I observed the first contact, its situation is sketched on Fig. 1. A thin film of clouds now covered the sun, but without materially interfering with distinct vision.

The moon made rapid progress over the sun's disc. Day-light began perceptibly to wane, when about 9-10ths of the sun's diameter was eclipsed, the landscape then assumed a sombre appearance, which rapidly darkened into an awfully black hue.

Under a power of 110 the mountains in the moon were visibly defined against the sun's bright disc. The position of these, as I observed them, is sketched on Fig. 2; they were situated chiefly on the southern cusp.

As totality approached, the sun's uneclipsed limb presented the appearance of a most brilliant golden thread of a segmental form, this instantaneously broke up into beads and strings of light, presenting the phenomenon known by the name of "Baily's Beads." These I observed on the southern cusp only, and in positions corresponding with those of the mountains in the moon; I have sketched them in Fig. 3. This phenomenon appears to me to be clearly accounted for by the sun's rays shining through the spaces or valleys between the mountains in the moon.

On the disappearance of the beads, the duration of which was very brief, (perhaps four or five seconds,) the corona and red prominences became visible. Fig. 4 is a representation of the sun during its total obscuration, it shews the corona and the red prominences. Of the latter, the two drawn on the following limb were the first seen, their form was conical, the bases being towards the sun, the base of each was about two-thirds of its height, they subtended an angle of about 38", making their height 17,780 miles. As the moon advanced, these soon disappeared.

On directing the telescope to the preceding limb, three more prominences came into view. The lowest of these, as shewn on the sketch, appeared like an inverted cone, the apex being towards the sun; it resembled fire violently shot forth from an orifice, diverging and decreasing in intensity as it ascended, until it was lost in the light of the corona. The appearance of the prominence next in succession was wonderful beyond description; after ascending vertically to a vast height, it bent off nearly at right angles in a southerly direction, extending itself nearly to an equal distance southwards; as the moon progressed in her orbit, it