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accessible to analysis, are those denoted by the surface winds in their annual and periodical returns, their similar climatic influences, the directions they usually take, and the constant course they follow, in displacing each other, &c. Thus, the examination of the meteorological registers kept at Port Macquarie, Port Jackson, Port Philip, and Port Arthur, show uniformly, at each of those stations, —
1. That the winds, in veering, follow constantly one course, viz., from the right to the left of the meridian facing the equator.
2. That the return of a N. W. hot wind is regular every summer season.
3. That, as regards the influence of winds on the thermometrical condition of the ambient air, those between N. and N. W. are invariably connected with the maximum of temperature ; while, on the contrary, the S. and S. W. are associated with the minimum.
4. That as regards their hygrometrical state, the N. and N. W. winds are the driest, and the S. S. E. and S. W. are the least dry.
5. That the winds which blow from the S. E. and S. W. quarter are associated with the maximum of atmospheric pressure, and those between N. E. and N. W. with the minimum, with the exception of the hot wind (N. W.), which causes the barometer to rise.
6. That as regards rain, its maximum at Port Philip, and the northern and southern parts of Van Diemen's Land, is seemingly dependent upon the agency of the N. E. and N. W. quarter; while the maximum of Port Macquarie and Port Jackson is accompanied invariably by winds from the S. E. and S. W.
Thus confirming the law which Prof. Dove had established, in his Meteorologishe Untersuchungen, not only as regards the inverted rotation of winds in the two hemispheres, but also their inverted effect on the barometer, thermometer, hygrometer, and pluviometer.
Again, each of these registers discovers a series of similar annual phenomena, but of so strictly local recurrence, that it becomes at once evident that, to the general laws which govern the atmospheric circulation, some other modifying laws, of a purely local nature, must be admitted.
Of these phenomena, the most prominent are the prevailing winds at each station, as exemplified in the following table, in which the total number of all the winds during a season is represented by 100.
Table II Of the prevailing Winds in New South Wales
and Van Diemen's Land.
At Port Arthur, then, the N. W. wind, as the table shows, prevailed during three succeeding winters; while, during the same winters, the S. W. prevailed at Port Jackson.
Again, during the three succeeding summers, a southerly wind prevailed at Port Philip; while, at Port Jackson, during the same seasons, the prevailing wind was northerly.
Farther, it appears, that of the four principal quarters of the compass, the northerly and southerly quarters furnish the greatest number of winds at each station, and that their numerical relations vary with seasons, and with each locality, thus: —
In Winter. — Van Diemen's Land, in each 100 winds, receives from the S. W. + S. + S. E. quarters 17 winds, and from the N. W. + N. -f N. E. 68 winds, making the polar to the equatorial as 1 : 4.
New South Wales, at its northerly stations, Port Macquarie and Port Jackson, has on the average, in each 100 winds, 60 proceeding from the S. W. + S. + S. E., and 21 from the N. W. + N. +N. E., making the polar to the equatorial as 3 :1. At Port Philip, however, the S. W. + S. + S. E. quarters furnish but 38 in each 100, while the N. W. + N. + N. E. give 50, making the polar to the equatorial as 1: 3.
In Summer Van Diemen's Land has, in each 100
winds, 28 which blow from the S. W. + S. + S. E. quarter, and 52 from N. W. + N. -f N. E., making the polar to the equatorial as 1:1-8. At Port Jackson and Port Macquarie, there are, in each 100 winds, 22 proceeding from S. E. -f S. 4- S. E., and 42 from N. W. + N. -j- N. E., thus rendering the proportion of the polar to the equatorial, as 1: 2. At Port Philip, the S. W. + S. + S. E. quarters give 69 winds out of 100, and the N. W. + N. + N. E. but 21, the polar to the equatorial being as 3:1.