[Tided Phenomena of Hobson's Bay. 163 



the 3rd November. On the 10th and 11th November, 

 although powerful winds blew on the 10th from the south- 

 west, they were not sufficient to force the waters up under 

 the pressure of a barometer at from 29*90 to 30 - 00 inches, 

 even with the strong lunar influence of a new moon ; but a 

 remarkable influence of the wind acting with the barometer, 

 is shown in the fall of the ebb tide on the evening of the 

 11th, under a sudden change of wind from south by west 

 to north-west. 



The same influences as above enumerated may be per- 

 ceived in a moderate form until, on the 16th and 17th 

 November, a sudden fall of the barometer and high gales 

 from the west-north-west, veering round by west to west- 

 south-west, drive up the waters to an unusual height, 

 although the moon had fallen to her last quarter. 



The gradual rise of the barometer, from the 18th to the 

 20th, again forces down the waters, although the winds are 

 from a quarter tending to keep them high. 



On the 22nd, a moderate fall of the barometer forces up 

 the water against a northern gentle breeze, whilst towards 

 midnight a gale from the south-west is unable to keep up 

 the tides under a rising barometer. 



From the 26th to the 30th, a high barometer again shews 

 its influence in depressing the waters, in the face of con- 

 tinuous breezes or gentle winds from the south, south-west, 

 and south-east. 



From the 2nd to the 9th December, the same influences 

 are felt of a high barometer keeping down the waters in the 

 face of breezes from the west, round by south to south-east, 

 until, on the 10th, a barometric fall of ^o-lOOths lifts the 

 waters upwards of six inches. 



The maximum of effect is shown on the 14th of December 

 with the barometer at 28*90, and a gale of wind from the 

 south-west blowing with a force of ten, being equal to 251bs. 

 pressure to the superficial foot, during which time the waters 

 are driven up two and a half feet higher than the ordinary 

 range of flood tide. On the 14th and loth, the midday ebb- 

 tides remain in one case twelve inches, and in the other 

 eighteen inches, higher than the ordinary level of preceding 

 flood-tides, whilst the midnight ebb-tide of the 14th did not 

 fall below the level of ordinary flood-tides, and the midnight 

 ebb of the 15th fell only a few inches below the same level. 



The diagram for the 14th and 15th of December is 

 remarkable for showing, under the combined influence of 



m2 



