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APPENDIX. 



from each side, that the western portion of this zone is affected. 

 Otaheite is thus at the edge, or Hmit, of four tides — one east, ano- 

 ther west, a third to the north, and a fourth to the south, and as 

 these tides are moving with different impulses, and at different 

 times, it is not at all surprising that they should almost neutralize 

 each other at Otaheite. As we go west or east of that island, we 

 find the tides augmenting gradually in height. At the Friendly 

 Islands they rise five feet, and at the Gambier Islands three feet. 



Respecting the twelve hour tide at New Ireland, and at other 

 places in the Indian archipelago — appeal to facts, so far as we can 

 trace the tides at present, tends to confirm the explanation of Sir 

 Isaac Newton, which consisted in supposing that such tides are coni- 

 pounded of two tides, which arrive by different paths, one six hours 

 later than the other. " When the moon is in the equator, the 

 morning and evening tides of each component tide are equal, and 

 the tides obhterate each other by interference, which takes place 

 about the equinoxes. At other periods the higher tides of each com- 

 ponent daily pair, are compounded into a tide which takes place at 

 the intermediate time, that is, once a day ; and this time will be 

 after noon or before, according to the time of year." — Whewell, in 

 Phil. Trans. 1833, p. 224. 



At New Ireland, the time of high water is about 3 ; but at New 

 Caledonia it is 9. Again, at the north-west coast of Australia, it is 

 12 ; and at the eastern approach to Torres Strait, 10 : at the Philip- 

 pine Islands it is 4 ; and at Loo Choo, 10. Now here are various 

 times of tide, and different impulses, crowded together into a com- 

 paratively small space, sufficient to perplex any theorist of the pre- 

 sent day. Owing to local configurations, and a variety of inci- 

 dental circumstances, we find every kind of tide in this region, in 

 a space sixty degrees square. Although tidal impulses, waves, 

 and resulting currents are checked and altered by the broken land 

 of the Indian archipelago, they cannot be suddenly destroyed, or 

 prevented from influencing each other, while communications, more 

 or less open, exist in so many directions. 



At the Sandwich Islands there is said to be very little tide. As it 

 is high water in 40° N., on the American coast, at 8 ; at which time 

 it is also high water at the Galapagos, it appears that the two 

 zones of the ocean — one about the equator, and the other near 40° N. 

 — have high water, in the meridian of the Sandwich Islands, at two 



