servations of the tides are necessary, and as these had not been obtained, and our limited stay, as well as the full employment for all our observers, which the necessary experiments with the magnetometers provided, did not admit of our doing it, I can only hope that some individual with like zeal for science with Mr. Lempriere, and with time at his disposal, may yet accomplish this desideratum. I may here observe, that it is not essential that the mark be made exactly at the mean level of the ocean, indeed it is more desirable that it should be rather above the reach of the highest tide: it is, however, important that it be made on some part of a solid cliff, not liable to rapid disintegration, and the exact distance above the mean level (which may also be marked more slightly) recorded on a plate of copper, well protected from the weather, by placing a flat stone with cement between, upon the plane surface or platform which should constitute the mark from which the level of mean tide should be measured.[1]
The most desirable position for such another mark would be near the north-west extremity of the island, and in the vicinity of Cape Grim, near which the Van Diemen's Land Company has a small establishment.
The fixing of solid and well secured marks for the purpose of showing the mean level of the ocean at a given epoch, was suggested by Baron von Humboldt, in a letter to Lord Minto, subsequent to the sailing- ↑ See Cosmos, p. 288. and note, p. 95.
