Page:A Voyage to Terra Australis Volume 1.djvu/465

Port Jackson.]

No remarks were made at this time upon the tide; but it is known to be high water in Port Jackson about eight hours and a quarter after the moon's passage over and under the meridian; and the usual rise to be between four and six or seven feet. When high water takes place between three or four in the afternoon and one or two in the morning, it rises from six to eighteen inches higher than the preceding flood; and the following ebb descends a few inches lower than that which preceded the high tide.

The range of the thermometer on board the ship, was from 51° to 69°; and nearly the same on shore. The mercury in the barometer stood from 29,60 to 30,36 inches; but it was remarkable that it stood lowest in the fine weather, when the wind came from the westward off the land, and was highest in the rainy, squally weather, with the wind from the sea. According to the information communicated by colonel W. Paterson, F.R.S., commander of the troops at Port Jackson, this relation between the mercury and the weather was general here in the winter season, when the eastern winds bring rain with them; and I had frequent occasion to remark upon the South Coast, that sea winds raised the mercury in the barometer, whilst those from the land, even with fine weather, caused it to descend.