294 AFPliXDIX. 



ing her power, and the wave is travelling toward the west, another 

 wave is approaching from the Pacific — a wave which has been retarded 

 in its passage— and its crest passes through the Indian archipelago, 

 while the water would otherwise be falling at the western part of 

 Torres Strait. At the same time, a derivative* wave moving north- 

 ward along the west Australian coast, combines vdth the Pacific wave 

 to raise a high tide about the north-west coast of Australia, where, 

 if it were not for these auxiharies, there would be low water at that 

 time. Six hours afterguards, one body has ebbed toward the 

 Pacific — the other southward, toward the then comparatively low 

 ocean, south of Australia, and what — if Torres Straits were blocked 

 up ; and the water prevented from falling away toward the south — 

 would be a high tide, is, in fact, low water. The tides in the two 

 northern bays are derivatives, and move northward. 



High water taking place at one time — within an hour — all along 

 the east coast of Africa, shows that the rise of sea, or tide-wave, 

 there moves westward or eastward, and the times of high water at 

 the islands are farther confirmations ; for the wave is at Chagos and 

 at the Mauritius three or four hours before it is high water on the 

 African coast. The KeeUng time shows that there the water rises 

 longer, in consequence of that part of the ocean being affected by 

 the advancing swell of the Pacific. 



The only remaining particular case which I now recollect is that 

 of the south coast of Australia — from King George Sound to Spencer 

 Gulf — a large space of sea, in which there is very little rise of tide — 

 and even that little very irregular. 



As the high water moves westward from the meridians of that 

 great bay, a tide moves southward from the Indian archipelago, 

 where it is high water just as it should be low in the bay men- 

 tioned : hence there is a filling, or flowing, from one wave, while an- 

 other is retreating. In this wide expanse, affected by derivative tides 

 from three adjoining oceans, we cannot but expect irregularities ; either 

 very high tides, caused by combination — or httle or no tide, in conse- 

 quence of mutual destruction — one tide ebbing from, whUe another is 

 flowing toward the same place. 



Throughout these remarks I have intentionally omitted to say 

 much of the sun's action, because, though very inferior, it is simi- 



• Derived from a great southern wave passing westward. 



