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. 285 In 30° S. at Coquimbo, it is high water at '2h. and at Norfolk Island it is high at about 9h. The intermediate space of ocean is nearly eight hours wide.* In 20° S., at Iquique, it is high water at Ih. 30m., and at New Caledonia, in the same parallel, it is high water at Sh. lom. The space between is about eight hours wide : the least diiference 4.15. Near 10°, or 12°, at Callao, it is high water at about ten ; but as on this parallel a multitude of islands spread across half tlie Pacific, no comparison of times can be trusted. On the equator — at the Galapagos Islands — it is high water at 8h. 20m. ; and at New Ireland it is high water at 3h. 00m. — a dif- ference of seven hours nearly. The ocean is here eight hours ^\^[de ; but at New Ireland there is only- one tide m tM'ent}'-four hours — an anomaly to be considered presently. The parallel of 10° N. is similar to that of the equator — however, we may as well examine it. At the little Isle of Cocos, and at Nicoya, on the main, it is high water at aljout 81i. ; and at the Philippine Islands, in the same latitude, at 4h. ; the difference, eight hours, ia not far from the meridian distance, which is about ten hours ; but the Phihppines also feel the effects of catises which influence the tides at New Ireland, and, generally, those of the Indian Archipelago. In 20° N. at San Bias, it is high water at 3h ; and at Loo-choo, the nearest know^l point of comparison at the other sic? o fthe ocean, at lOh. The difference, 7 hours, is about an hour less than the meridian distance. In 30° N. on the Coast of Cahfornia, it is high water at 4h., and at Nangasaky, in Japan, in lat. 32° 44', at 11.12. The difference, 7.12, is nearly half an hour less than the meridian distance. In 40° N. it is high water at about 8h. on the American coast, but for the opposite shore I have no data. In 50° N. it is high water on Vancouver Island at 9h., and at the south extreme of Kam- schatka it is said to be high water at about 6h. ; the difference, 9 or 3 hours, is anomalous — made so probably by a derivative tide. Havmg examined the Pacific, let us proceed in a similar manner with the Atlantic, and the Indian Ocean : In 40° S. off Blanco Bay, the time of high water is 9h. ; the same as at the Falklands. At Amsterdam Island, one authority says 6h., another I2h, for the * A derivative tide (p. 28'J) may act here.