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. 253 mixed together, called tosca ; and the heavy swell that sets round the point causing almost a roller, brings a vessel up to her anchor and throws her back again with a sudden jerk, each of which makes her drag, or endangers snapping the cable. Vessels having to anchor here ought not to shut the southern point the Morro in with the next point to the northward : by keeping this mark open they will be in eight or nine fathoms, and not have so much swell as there is further in. The landing is very bad ; canoes built purposely and dexterously managed are the usual means of com- munication : no doubt there are times when a ship's boat may land without danger, but very seldom probably without the crew being thoroughly drenched. From ChoriUos the coast runs in a steady sweep with cliffs of less height, tiU it reaches the Point of CaUao, which is a shingle spit, stretching out toward the Island of San Lorenzo, and with it forms the extensive and commodious Bay of CaUao. The Island of San Lorenzo, which is 1050 feet at its highest part, is four miles and a half long, in a N.W. and S.E. direction, and one mile broad. OiF its S.E. end lies a small but bold-looking island, called Fronton, and to the S.W. are the Palominas rocks : its northern end, or Cape San Lorenzo, is clear, and round it is the usual passage to the anchorage at Callao. In rounding this Cape do not close the land nearer than half a mile, for within that distance there are Hght baffling airs caused by the eddy wind round the island by getting among which you would be more delayed than if you gave the island a good berth, and should have to make an additional tack to fetch the anchorage. This is the usual route ; but there is another which, with common precaution, may be used to great advantage, by vessels coming from the southward. This is the Boqueron, formed by the Island of San Lorenzo and CaUao Point. After making San Lorenzo and Fronton, steer so as to keep the south extreme of the latter about a point open on the bow port ; and keep on this course until Callao Castle is seen, which has two marteUo towers on it, and is situated on the inner part of the shingle spit, that forms the point : then steer for it till Horadada Island (with a hole through it) comes on with the middle of the southern sandy bay of the Morro Solar, and with the inner declivity of the hill on Solar Point bearing S. 66° E. : with these marks on, and steering N. 66° W., for the furthest point of