Port Jackson.] 
TERRA AUSTRALIS. 
239 
Variation of the compass, observed by lieutenant I802. 
n July. 
Flinders on Garden Island in the following 
year, - - - 8* 51' east. 
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 quar- 
ter 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 0 to 6g°; 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. 
