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and ten, A.M., in winter, represents the daily
mean of each season. 2. That the minimum of temperature of summer
is equal to the mean temperature of winter. 3. That the maximum of winter corresponds to
the mean of summer.
CONCLUSION. To this rapid and imperfect sketch of the prevailing constitution of the atmosphere, as regards winds, currents, atmospheric pressure, rain, evaporation, radiation, absorption, and emission of heat, dew, moisture, and, finally, temperature, a brief recapitulation of the main evidences is added, in order that the climatic concomitants to which they refer, being placed in nearer and more prominent relation to each other, may the better illustrate, whether by comparison or otherwise, the climate to which they belong.
The Australian winds and currents, considered in relation to the main effects they produce on pressure, moisture, and temperature, have been shown to possess a striking analogy to the winds and atmospheric currents of Europe and other parts of the world; which, consequently, renders the conclusion plausible, that their constitution and agencies possess nothing peculiar or exceptive, by which these winds could be viewed as characteristic of the zone to which they belong. The hot wind, even, was found to resemble similar winds in Asia (Jakoutsk), Africa, North America (Lower California), South America (Acatama), and the Indian Archipelago, with this remarkable difference, that its short duration, not exceeding ten hours, and its rare occurrence, which takes place but twice or thrice per annum, prevent in a great measure the extent of mischief and injury to which the above-named parts of the globe are exposed. Thus, while in Asia and Africa the hot wind forms a concomitant of the climate, in New South Wales and Van Diemen's Land it must only be classed amongst the extraneous agents which casually disturb a wellordered climatic economy, as do those winds in the south of Europe known under the names of Sirocco, Mistral, &c.
As regards rain, it was proved to be more plentiful in New South Wales than in Van Diemen's Land, a startling fact, to those acquainted with the localities, but which, based on numerical elements furnished by six different stations, is undoubtly correct. Both the colonies, as compared to England, have been shown to receive a larger amount of rain than does Brussels, Berlin, Geneva, York, and, lastly, London, so celebrated for its humidity.
Further, as regards evaporation, the fact was clearly made out, that water exposed to evaporation, under similar circumstances, will lose, whether in the monthly or annual amount, nearly the same quantity in New South Wales as in Van Diemen's Land; whereby is demonstrated, that the power of the atmosphere, as regards its mechanical resistance to the diffusion of vapours, and its power of influencing the elasticity of such vapours, and consequently of promoting their diffusion, is exactly the same in the two colonies. The absolute amount even of annual evaporation of water, as shown by the register of the evaporating gauge, was found to be very near that which an evaporating dish gives in London.
The observations detailed under the head of Solar Heat, &c., led to the conclusion that the intensity and effects of solar rays are greater in New South Wales than they are in Van Diemen's Land; but that, owing to the difference in the diaphaneity of the surrounding medium, Van Diemen's Land is exposed to a greater intensity of solar rays than New South Wales.
and its por consequen
the two The next division brought to light the existence of still greater modifications of the action of solar rays in the two colonies : it went even farther-it showed, by the elements of the relative power of absorption and emission of heat which soils possess, and by the proportion which the different kinds of rocks bear to each other, that such is the influence of the geological formation of New South Wales and Van Diemen's Land upon the received amount of solar heat, that, had it not been from other concomitants of climate, the two colonies would have been unavailable to civilisation. But Providence, in its kind dispensation, has modified and adjusted, by means of vegetation and diaphaneity of the atmosphere, this effect of solar heat, and thus put a most admirable check upon the excess of caloric and refrigeration.
Again, under the head of Moisture, the soils, the vegetation, and the diaphaneity of the atmosphere have been shown to possess as great an influence upon the hygrometrical condition of the colonies as that which they so beneficially exercise on the effects of solar heat. By the examination of the numerical elements relative to dew, and tension of vapours, Van Diemen's Land was proved to possess a greater moisture than New South Wales. Both colonies nevertheless, as compared with other countries, show a lower hygrometrical mean than is usually allotted to them: thus Van Diemen's Land was shown to have very nearly the same degree of moisture as London.
As to the colonial temperature, which comprehends so many different climatic effects and agencies, the reader cannot but be struck with the range and favourable thermometrical condition in which every locality illustrated under the head of Temperature is found to be placed, when compared to other localities on the globe.
Port Macquarie, in that comparison, is seen to possess the summer of Florence, Barcelona, Rome, or Naples, the winter of Funchal or Benares, and a thermometrical fluctuation similar to that of Dublin: by its annual mean it may be classed with the climate of Tunis.
Port Jackson, again, is, by a similar comparison, found to have the summer of Avignon (France), Constantinople, Baltimore (United States), or Philadelphia, and a winter very nearly similar to that of Cairo (Egypt), or of the Cape of Good Hope. Its fluctuations correspond with those of Paris, and its annual mean temperature with Messina (Sicily) and the Cape of Good Hope.
Port Philip resembles, in its summer season, Baden, Marseilles, and Bordeaux; in its winter, Palermo or Buenos Ayres: the fluctuations of its temperature are those of Montpellier, and its annual mean is that of Naples.
Woolnorth possesses the summer of Freiberg, Bay. reuth, Berne, or Cheltenham, and a winter similar to that of Algiers or Messina: its thermometrical fluctuations are similar to those of Havanah and Cumana, and its annual mean to Madrid and Avignon.
Circular Head is found to have the summer of Kracow, Prague, Lausanne, Würtzburg, Karlsruhe, the winter of New Orleans, and the annual mean of Toulon, and St. Fé de Bagota (South America).
Launceston, in its summer, reseinbles Manheim, La Rochelle, and Toulouse, and in its winter and its annual mean, Lisbon and Perpignan.
Lastly, we see Port Arthur, the extreme southern station of Van Diemen's Land, possessing the summer of Tilsit, Dantzic, Augsburgh, and Jena, and a winter like that of Smyrna.
According, then, to the above, the thermometrical fluctuations assimilate New South Wales and Van Diemen's Land to a tropical region : the summer
season of the two colonies resembles the summer of that part of Western Europe which lies between latitude 41° 53' and 55° 57', and the winter that part of the Mediterranean which is enclosed between the coasts of Spain, Italy, France, and Algiers, extending to Tunis and Cairo; and thus is concentrated within the space of 11° of latitude the elements of seasons most requisite and essential for exalting all the energies of animal and vegetable life.
Independently, however, of comparison and analogies, the climatic condition of New South Wales and Van Diemen's Land is represented in the most favourable light by its rich flora, and by the healthy condition of its aborigines and indigenous animals. Looking, indeed, at the singular and distinctive features by which its organic life is characterised, making this continent as it were a world apart, we cannot but wonder that the same climate under which that life appears should be likewise so well adapted to the maintenance of the vegetation and the animals of other hemispheres. The effect produced by the appearance of the plantain growing in company with the vine, apple, peach, and the English oak, — which is the case at Tahlee, head station of the Australian Agricultural Company, - and these again flourishing in the close vicinity of the Eucalyptue and Mimosa, is indeed surprising; nor is it less surprising to behold the kangaroo, sheep, emu, and the horned cattle roaming together in the same forest, and seeking sustenance from the same herbage.
But what mainly illustrates the fertility and salubrity of both these countries, is the healthiness of the English settlers who have taken root in the soil. No endemic disease, and seldom any epidemic of grave character, prevails; and if individual indisposition, or even partial deterioration of the progeny, is sometimes seen, it is to be traced to the pertinacity with which