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

CHAPTER XVIII. Leave Chiloe — Valdivia — Earthquake — Aborigines — Traditions — Words — Convicts— Tolten — Boroa — Imperial — Mocha — Shocks of Earthquake — Anchor oif Talcahuano — Ruins — Account of a great Earthquake which destroyed the city of Concepcion : and was felt from Chil6e to Copiapo ; from Juan Fernandas to Mendoza. At daylight on the 5th of February the Beagle sailed from Chiloe, and passed along the coast of southern Chile, towards the port of Valdivia. This is a bold and high tract of land, without a danger for shipping to avoid ; but, at the same time, without a safe anchorage between the ports above-mentioned. Soundings extend some miles into the offing, though the water is deep. At two miles westward of this shore we usually found about forty fathoms water ; at three miles about sixty, and at five miles from seventy to eighty or ninety fathoms, with a soft, sandy, or muddy bottom. Whenever, as in this case, we were obliged to carry on the survey without landing, our observations for latitude — often those for time also — were made at the opposite points of the horizon, as well as in the usual manner, when land did not intervene, and the mean results taken as the most correct. In this way, it is probable that errors occasioned by refraction were in a considerable degree avoided.* The day before arriving at Valdivia we had a strong nor- therly wind, with cold, rainy weather, though the glasses were high. Such an anomaly I have elsewhere noticed, especially in Tierra del Fuego ; but any attempt to explain it must be deferred. Another singularity was the temperature of the * We had three sextants, made for me by Worthington, which had additional horizon glasses, enabling them to measure any angle less than 160°. The contrivance was my own, and found to answer. It is des- cribed in the Appendix.