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. 279 been siinilarl}^ perplexed, I could have little doubt, having often talked to experienced practical men on the subject. Probably the expressions ' tide and half-tide,' ' tide and quarter-tide,' &c., con- veyed more distinct ideas to their minds, than to mine : for to me they were unsatisfactory, and although quite aware of their meaning, I never liked them. From 1833, I and my companions on board the Beagle paid more attention to the subject, and made obser- vations in the manner suggested by Mr. Whewell, as often as our other avocations allowed. It was, however, impossible to take interest in the subject, and discover difficulties, facts irreconcileable to theory, without trying to think how to account for them — unquaHfied even as I knew myself to be for such a task.* Perhaps I was encouraged to meditate by Mr. Whewell's concluding paragraph ; f and, sepa- rated from assistance, I tried to reason my way out of the dilemma, by the help of such few data as I could dwell upon vpith certaint}^ * Among the points which I could not establish in my own mind, by appeal to facts, were — " the tides of the Atlantic are, at least in their main features, of a derivative kind, and are propagated from south to north." (p. 164.) "That the tide. wave travels from the Cape of Good Hope to the bottom of the Gulf of Guinea, in something less than four hours." (p. 167.) " That the tide-wave travels along this coast (American) from north to south, employing about twelve hours in its motion from Acapulco to the Strait of Magalhaens." (p. 194.) " From the compara- tive narrowness of the passage to the north (of Australia), it is almost certain that these tides must come from the southern side of the conti- nent." (p. 200.) " The derivative tide which enters such oceans (North and South Pacific) from the south-east, is diffused over so wide a space, that its amount is also greatly reduced." (p. 217.) &c. t " I cannot conclude this memoir without again expressing my entire conviction of its very imperfect character. I should regret its publication, if I supposed it likely that any intelligent person could consider it other- wise than as an attempt to combine such information as we have, and to point out the want and the use of more. I shall neither be surprised nor mortified, if the lines which I have drawn shall turn out to be, in many in- stances, widely erroneous : I offer them only as the simplest mode which I can now discover of grouping the facts which we possess. The lines which occupy the Atlantic, and those which are near the coasts of Eu- rope, appear to have the greatest degree of probability. The tides on the coasts of New Zealand and New Holland, have also a consistency which makes them very probable. The Indian Ocean is less certain ; thougli it is not easy to see how the course of the lines can be very widely diffe- rent