"A portion of the spirit extending over about 10-1/2 deg. (and standing tween 33 deg. and 43-1/2 deg.) was separated from the rest, but there appeared to be no data for determining when the separation had taken place. As it appeared desirable to unite the two portions of spirit before again setting the index to record the cold of another winter, we endeavoured to effect this by heating the bulb, but unfortunately, just as we were expecting to see them coalesce, the bulb burst, and I have now to express my great regret that my clumsiness or ignorance of the proper mode of setting the instrument in order should have interfered with the continuance of observations of so much interest. The remains of the instrument, together with a note of the accident, I have left in the charge of Wellig, the landlord of the hotel on the AEggischhorn. "We reached the summit about 10.40 A.M. and remained there till noon; the reading of a pocket thermometer in the shade was 41 deg. F. "Should there be any further details connected with our ascent on which you would like to have information, I shall be happy to supply them to the best of my recollection. Meanwhile, with a farther apology for my clumsiness, I beg to subscribe myself yours respectfully, "H." "Professor Tyndall." (17.) [Sidenote: A ROTATING ICEBERG. 1858.] On the 6th of August there was a long fight between mist and sunshine, each triumphing by turns, till at length the orb gained the victory and cleansed the mountains from every trace of fog. We descended to the Maerjelen See, and, wishing to try the floating power of its icebergs, at a place where masses sufficiently large approached near to the shore, I put aside a portion of my clothes, and retaining my boots stepped upon the floating ice. It bore me for a time, and I hoped eventually to be able to paddle myself over the water. On swerving a little, however, from the position in which I first stood, the mass turned over and let me into the lake. I tried a second one, which served me in the same manner; the water was too cold to continue the attempt, and there was also some risk of being unpleasantly ground between the opposing surfaces of the masses of ice. A very large iceberg which had been detached some short time previously from the glacier lay floating at some distance from us. Suddenly a sound like that of a waterfall drew our attention towards it. We saw it roll over with the utmost deliberation, while the water which it carried along with it rushed in cataracts down its sides. Its previous surface was white, its present one was of a lovely blue, the submerged crystal having now come to the air. The summerset of this iceberg produced a commotion all over the lake; the floating masses at its edge clashed together, and a mellow glucking sound, due to the lapping of the undulations against the frozen masses, continued long afterwards.