Of course you come to Sicily.… Lockyer thinks of going on December 8th. Perhaps I may go a day earlier—with you if you can come—and spend twenty-four hours in Heidelberg.
I send box, stand, papers, and all I can find—except insolation affairs which cannot yet be got out of H⸺’s hands. He shall have no peace till they are ready, and they shall then be sent at once to you. You will be responsible for the whole apparatus being in order. Look them over carefully.… You know what is wanted.
Unfortunately H.M.S. Psyche, the vessel conveying the party from Naples, was wrecked off Aci Reale, about a couple of miles to the north of the classic Cyclops rocks, and under the shadow of Etna, by striking a submerged and uncharted rock. The ship was badly holed, and rapidly began to fill, but fortunately the weather was fine and the sea calm, and all were got safely on shore. The cliffs were scarcely 200 yards away, but the landing was difficult, the jagged reefs of lava seeming to afford no sure footing. Eventually all the instrumental equipment was also landed, in a more or less damaged condition, but much of the personal baggage was lost. A letter written by one of the members of the expedition which found its way into a Manchester newspaper thus describes the event:
We formed ourselves into a line to pass the things along the rocks to the prominence which we had mounted.… Everybody worked with a will, and laboured like galley-slaves. The ship had now settled down considerably; the water was up to her quarter, and the boats pushed off in the expectation that she would roll off the reef. By this time we had almost stripped the ship of everything easily movable, and we prepared to get it to a secure place. The nearest point habitable was Catania, seven miles to the south, and we got the boats ready to take ourselves and our things thither.… Roscoe assumed command of our expedition. Everybody seemed to look to him instinctively. I shall never forget the sight of him, standing, with his legs apart to steady himself on a narrow piece of the lava rock, with his arm stretched out, giving his orders with the authority of one who seemed born to command. As the gig was about to push off I saw him look round, and when he saw me he motioned for me to get into it.… In a few hours the remainder of the party arrived, and shortly afterwards the luggage and apparatus.
It was arranged that Roscoe, assisted by the late Sir George Darwin and Mr. Bowen of Harrow School, should make observations on the spectrum of the corona from a position on Mount Etna as high as the snow would permit. On the day before that of the eclipse the party had toiled up more than 5,000 feet of the mountain with their instruments strapped on the backs of half a dozen mules, to a deserted hut on the side of the volcano. The night was spent in a storm of rain and snow, and next morning, in a piercing wind, the instruments were put together with benumbed fingers. As the sun was gradually covered, the sky became clouded over and the upper part of Etna was completely enveloped in fog, and during the minute of totality a violent hailstorm broke over the party, rendering all observations impossible.
A number of measurements of the chemical intensity of daylight during the progress of the eclipse were, however, made by the writer at Catania, some little distance away, by the method described by Roscoe in the Bakerian Lecture for 1865. These showed that the diminution in the total chemical intensity of the sun’s light during an eclipse is directly proportional to the magnitude of the obscuration of the solar disc.[26]
This matter is referred to in the following letter.
June 11, 1871.
The results are very interesting, and you have worked them out in an admirable manner. I had no idea that so much could be made out.
I am writing at once to Airy and Lockyer to ask them whether we may not send the paper to the Royal Society (last meeting on Thursday next) so as to have it in series with our other papers.