1802
January.
arithmetic progression from those of the Cape of Good Hope to the new ones of King George's Sound, the mean of Earnshaw's two time keepers will then differ only 8′ 19″ to the east in forty-four days. In fixing the position of places from Cape Leeuwin to the Sound, these accelerating rates have been used; and the longitude has been further corrected by allowing an equal proportion of the error, 8′ 19″, according to the number of days after Nov. 1, when the last observations were made at the Cape of Good Hope. In the Appendix, the nature of these corrections is more particularly explained.
The height of the thermometer at the tents, as observed at noon, varied between 80° and 64°. On board the ship, it never exceeded 70½°, nor was below 60°. The range of the barometer was from 29,42 inches in a gale of wind from the westward, to 30,28 inches in a moderate breeze from south-west.
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Mean Dip of the S. end of the needle, taken on shore, . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . |
64 | 1 |
On board, upon the cabin table, . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . |
64 | 52 |
The increase being probably occasioned by the iron ballast in the bread room underneath.
The Variation given by three compasses at the observatory was 6° 22½′ west, by Walker's meridional compass 5° 25′, and by the surveying theodolite 8° 17′; but upon the eastern part of the flat granite rock, on the south side of the sound, two theodolites gave only 4° 1′ west. On board the ship, at anchor off Point Possession, the variation from the three compasses on the binnacle, when the head was south-eastward, was 9° 28′; or, corrected to the meridian, 7° 12′ west. It seems not easy to say what ought to be considered as the true variation; but the mean of the observations at the tents being 6° 42', and on board the ship 7° 19′, I conceive it will not be far wrong if taken at . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . |
7° 0′ west. |
