the barometer and thermometer during my absence, while his brother observed below at Catania, and I carried up my mountain barometer and other instruments to the summit. From Nicolosi the ascent becomes rugged and laborious, first through a broad belt of fine oak forest, which encircles the mountain like a girdle about its middle, and affords some beautiful romantic scenery—when this is passed we soon reach the limits of vegetation, and a long desolate scorched slope, knee-deep in ashes, extends for about five miles to a little hut, where I passed the night (a glorious starlight one) with the barometer at 21⋅307 in.—and next morning mounted the crater by a desperate scramble up a cone of lava and ashes, about 1,000 feet high. The sunrise from this altitude, and the view of Sicily and Calabria, which is gradually disclosed, is easier conceived than described. On the highest point of the crater I was enveloped in suffocating sulphurous vapours, and was glad enough to make my observation (bar. 21⋅400) and get down. By this the altitude appears to be between 10 and 11,000 feet. I reached Catania the same night, almost dead with the morning's scramble and the dreadful descent of near thirty miles, where the mules (which can be used for a considerable part of the way) could scarce keep their feet.
Florence, Aug. 16th, 1824.—In the hurry and bustle of travelling one is obliged to write by snatches when one can. . . . . I hope to hear from you at all events when I reach England if I should not see you first, of which I begin now to have serious doubts, having been so terribly retarded in my Sicilian journey, and at Naples, on my return, by the illness of a friend.
Your affectionate nephew,
J. F. W. Herschel.
P.S.—Have you heard how M. Pfaff's translation proceeds? I wrote to him from Cattagione, in Sicily.
