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

APPENDIX. 185 blow nearly so strong as from north-west to north, or from south- west to south. Currents. Near the island of Mocha, and to the westward of Cape Rumena, the cun-ent usually runs to the north-west, from half-a-mile to one mile and a half, each hour. Distant in the ofRng, more than twenty or thirty miles from land, this set of current is so diminished that it is hardly sensible ; but near Mocha, and especially near the very dangerous out-lying rocks oiF the south and south-west extreme of that island, it is increased to two, and, at times, even three miles an hour. From the great river Bio Bio, and from other rivers in the vicinity, floods, escaping to seaward, often cause strong and irregular currents which set to the southward — passing the island of Santa Maria, sweeping round Point Lavapie, and Cape Rumena, and Tucapel Point — into the bay where his Majesty's ship Challenger was wTecked. These southerly currents are usually found to set strongly along- shore, but seldom reach an offing of six miles to the westn^ard of Cape Rumena. A very intelligent Hanoverian, Anthony Vogelborg, employed during several years upon these coasts, was once drifted in a small vessel, from six miles south of the Paps of Bio Bio, to the rocks oif the north end of the Island of Santa Maria, in one night, during a dead calm. After the great earthquake of the 20th of February, which affected all the coast about Concepcion, and especially the Island of Santa Maria, the currents set to the south-eastward so strongly, that a boat belonging to the above-mentioned Anthony Vogelborg (which he was steering) running near the Island of Mocha, under sail, with a fresh southerly breeze, could hardly make head against the strong stream that was passing along shore from the north-westward. It is, there- fore, to be apprehended, that the strength and direction of the cur- rents in the neighbouring ocean are unsettled and extremely uncer- tain for some time after a serious earthquake.