The evidence of former changes in climate was thus strongly impressed on Lyell’s mind, and the astonishing truth began to be strongly impressed upon geologists by him, that not only has the area of Europe witnessed ages of tropical heat, but also ages of considerable winter’s cold, and that there has been more than one glacial period. Lyell visited Vesuvius and Etna in 1858, and how carefully he noticed every detail of the mountain structure, and how little he cared about “roughing it” may be gleaned from extracts from his diary sent to his wife:— “Etna, _Casa Inglese_, Sept. 21, 1858.—Got off with two guides and two muleteers and four mules, at half past seven, in bright sunshine, from Nicolosi, and after a beautiful sunny ride of three hours through wooded craters, protected from the heat by my umbrella, was gradually enveloped in clouds. I saw a lava stream where the oaks had been surrounded by lava, which had taken the form both of upright and prostrate trunks, surrounding them with tuff, and the wood being burned up they are now cylinders of scoriaceous lava. After a couple of hours we got above the clouds, when about eight thousand feet high, but not till my hands were numbed, for I could not believe for a long time in the necessity of my putting on a cloak. After reaching this place, I set out with Angelo for the top of Etna, leaving Guiseppe to cook. We had now and then a drifting cloud, but on the whole splendid sunshine. I saw the spot at the foot of the great line where the Catanians quarried ice from under a current of lava. My guide saw the same thing some six years ago, while the eruption of 1852 was in progress, in August and September: the sand and lava ten feet thick, and four feet of ice below, and bottom not seen. Not far above the ice I warmed my hands at a fumarole where the steam and some sulphuretted hydrogen were given off at such a heat that I was obliged to be careful how I put my fingers in. This welcome heat enabled me to write. When we reached the edge of the crater the whole of Sicily was hidden except the higher part of Etna, between us and Montagunoli. But Lipari and Stromboli stood out in the sea very conspicuously. I made a rough sketch of the two craters; the smaller one has lately, I believe, fallen, and shows a section of some of the horizontal beds of lava, with which it had been filled nearly to the top. It was a considerable exertion climbing and going half round it after a seven hours’ ride, and this makes the Casa Inglese, which is the roughest place I was ever in, seem a hospitable mansion, as it saves our returning. The wind is whistling round and somewhat through it, but Dr. Guiseppe, I hear, has made it weather tight. There is no chimney and we have charcoal burners, but if the wind always blows like this I am not, at any rate, guaranteed from asphyxia.”