On the Cyelones of Tasmania, ce. 899 
the 31st July to the 8rd August the mercury is low, and 
oscillates within moderate limits, and the wind is variable 
and moderate (4, 5, 2). On the 4th August the South 
Western quadrant approaches, and continues its passage 
until the 7th, the wind being steady at K. and then at S.E. 
On the 8rd there is a calm, and on the Helios days the 
force of the 8.E. wind is 3, 4, and 5. 
At Sydney, on the 80th, the changes of wind were 
N.W., W.N.W., W., W. by S., and W.S.W., indicating the 
transit to the eastward of the extreme northern margin. 
That the track of the centre lay between the parallels of 
Van Diemen’s Land and the Auckland Islands is shown by 
the order of veering of the wind at each of these places. 
Consequently, a shorter chord of the Cyclone passed over 
Melbourne and Sydney than over Hobart Town. This ac- 
counts for the great breadth of the barometric depression 
at Hobart Town, indicating that the mercury began to fall 
sooner there, and was longer in rising, than at the more 
northern stations. The eastward progress of the Cyclone 
is likewise demonstrated by the comparison of the several 
barometric curves, (fig. [X.)*; for the minimum depression, 
which occurs almost simultaneously at Melbourne and Hobart 
Town, happens early next day at Sydney, (4° to the East- 
ward) and at least two days later at the Auckland Islands, 
(18° to the eastward.) Since the Northern Margin ex- 
tended to Sydney, and the Southern to the Auckland Islands, 
the diameter of the whole Cyclone was not less than 1000 
miles. 
Assuming the centre to have passed the Duke of Tan. 
caster in 120° EB. early on the 28th, the meridian of Van 
Diemen’s Land early on the 80th, and that of the Auckland 
* See “ Australian Cyclonology.” 
