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. 243 as much as one knot per hour) setting to the westward, have been prevented from anchormg for several days. This, no doubt, has been partly owing to the hitherto inaccurate position assigned it, and from a proper reluctance to expose a vessel on an imperfectly known coast, to be baffled and drifted about by light and variable airs, in addition to a heavy swell continually roUing directly toward the shore. With the following directions, it is to be hoped that more confi- dence wiU be acquired, and consequently less delay occasioned in sailing to the seaport of the second city of Peru. Coming from the southward, the land abreast of Tambo should be made, and a certainty of that place ascertained, which (according to the state of the weather) may be seen from three to six leagues : the course should then be shaped toward a gap in the mountain to the westward, with a defined sharp-topped hill in the near range, a short distance from it. In this gap is the road leading to Arequipa, which winds along the foot of the before-named hill from Islay. As the coast is approached, the foot of the hills wiU be seen to be covered with white ashes (said to have been thrown from the volcano of Arequipa), not found on any other part of the coast. This peculiarity commences a httle westward of Tambo, and continues as far as Point Omilius, and when within three leagues, the Point Islay and white islets forming the bay, will be plainly observed, and should be steered for. Care must be taken in closing the point, as a rock, barely covered, lies a quarter of a mile to the southward. It is the custom to go to the w .stward of all the islands ; but, with a commanding breeze, it would unquestionably be better to run between the third outer and next island,* which enables you to choose your berth at once ; this can seldom be done by the other route, the wind heading as you enter, obliging you to anchor, and use warps. The best anchorage is just within Flat Rock Point, off the landing-place, in ten or twelve fathoms. A hawser is necessary to keep the bow to the swell, to prevent rolling heavily, even in the most sheltered part. Vessels from the eastward should close the land about Tambo, and observe the same directions. If from the eastward the parallel of seventeen degrees five minutes • His Majesty's ships Menai and Challenger passed in between these islands.