Narrative of the surveying voyages of his majesty's ships Adventure and Beagle (vol.2): between the years 1826 and 1836 : describing their examination of the southern shores of South America, and the Beagles's circumnavigation of the globe

1833. MOUNTAIN TOPS — BONES. 277 since occurred to me, that the phosphoric light spoken of by Bougainville in the following passage may be of a nature simi- lar to that which I saw, and that those momentary flashes might have been caused by the occasional fall of stones among ravines, near the summits of hills. " Des voyages entrepris jusqu' au sommet des montagnes (pour chercher des calcaires), n'en (de pierre) ont fait voir que d'une nature de quartz et de gres non friable, produisant des etincelles, et meme une lumiere phosphorique, accompagnee d'une odeur sulphureuse." — (Bougainville, Voyage autour du Monde, 1766-69, tome I., p. 100). The shattered state of most summits of mountains in these regions* has often struck me, many of them being mere heaps of rocks and stones, over which it is extremely difficult to climb. Mount Skyring may be cited as one remarkable instance ; there, the stones gave out a very sulphureous smell when struck together, and were strongly magnetic.-f- Light- ning, electricity, and magnetism being intimately related, one is led to think that, if the above conjecture is incorrect, there may be some connexion between these sudden glimpses of faint light and the transmission of the electric fluid. This much I am certain of, that they were not lights made by man, and that they were different from the will-o'-the-wisp, or ignis fatuus. My own employment obliged me to remain near the ship, but some of the officers made excursions into the interior, and to them and Mr. Brisbane I am indebted for most of the fol- lowing notices of these islands. Some very large bones were seen a long way from the sea- shore, and some hundred feet above the level of high water, near St. Salvador Bay. How they got there had often puz- zled Mr. Vernet, and Brisbane also, who had examined them with attention ; Brisbane told me they were whale's bones.]: The rocky summits of all the hills are amazingly broken up, * Falklands and Tierra del Fuego. f Vol.1., p. 382. % Bougainville says, " D'autres ossemens enormes, places bien avant dans les terres, et que la fureur des flots n'a jamais ete capable de porter si loin, prouventque la mer a baisse, ou que les terres se sont elevees." Vol. I., pp. 112-113.