OCR Text |
Show 268 'l'IERUA DEL FUEGO. June, 1834 · smallest change of level, as channels connecting the Strait of Magellan, in the one case with the open sea, and in the other with Otway Water. The climate of the southern part of South America presents many phenomena of the highest interest. It has long been observed that there exists some essential difference between it, and that of the countries in the northern hemisphere. I have already remarked on the surprising contrast between the rank vegetation of the broken west coast, consequent on the humid climate, as compared with the dry and sterile plains of Patagonia. The clouded and boisterous state of the atmosphere is necessarily accompanied by a decrease in extreme temperature; hence we find that fruits which ripen well, and are very abundant, such as the grape and fig, in lat. 41° on the east coast, succeed very poorly in a lower latitude on the opposite side of the continent.* The result is more strongly marked, if we take Europe as the standard of comparison. In Chiloe, lat. 42°, corresponding to the northern parts of Spain, peaches require the greatest care, and seldom produce fruit; but strawberries and apples succeed to admiration. At Valdivia, lat. 40°, or that of Madrid, standard peaches bear abundantly; grapes and figs ripen, but are far from common; olives seldom even partially ripen, and oranges not at all; yet in Europe this is the parallel most productive of these fruits. . Even at Concepcion, lat. 36°, oranges are not abundant, though the other named fruits succeed perfectly. At the Falklands, in the same latitude as the south of England, wheat very seldom comes to maturity ; but we ought to feel little surprise at this, when we hear that in Chiloe (lat. 42°) the inhabitants are frequently compelled to cut their corn before it is ready, and bring it into their houses to dry. With respect to the climate of Tierra del Fuego during • As there are no settlements on the Patagonian coast, there are few means of comparison. Cherry-trees left by the Spaniards at Port Desire, lat. 48°, still bear fruit, whereas, in Chiloe, on the west coast, 360 miles further north, I believe they do not succeed. June, 1834. CLIMATE. 269 the colder parts of the year, Captain King has published some most interesting tables in the Geographical Journal.* The Beagle during this voyage, was employed in the extreme southern parts of the country, from December 18th to February 20th. From the appearance of the vegetation during the first part, and from the weather we experienced at the Falkland Islands, subsequent to the last date, I feel little doubt that these sixty-five days included the-.best part of the summer. Perhaps if another fortnight had been added, the mean would have been a little higher. The first eighteen of these days were spent partly at sea, near Cape Horn, and we were drifted for a short time by bad weather to nearly ninety miles to the southward. The mean temperature, from observations made every two hours by the officers on board the Beagle, was 45°. During the succeeding thirty-seven dayst the Beagle was at anchor in different harbours a few leagues north of Cape Horn, and then the mean from observations at 6 A.M., noon, and 6 P.M., was 50°. The mean, therefore, between these two periods, which include the hottest part of the year, is only 47°. 5. The latter of the two periods was unusually warm, but the former much the contrary, and the station where the observations were made was a little further to the southward. The whole of these observations apply to the extreme islands : Captain King's were made in a central position 1° 45' further northward. If from the above considerations we add two degrees and a half to the mean obtained this voyage, the result (50°) will probably give the temperature of the hottest part of the year in central Tierra del Fuego. Captain King gives as the mean temperature of June 32°.97, of July 33°.03, of the first twelve days in August 33°.25; • Journal of the Royal Geographical Society for the years 1830, 1831. t The mean of the maxima of these thirty-seven days was only 55° . 5, and of the minima 45°. 3,-the mean range thus being 10°. 2. For the whole sixty-five days, the mean of the maxima was ouly 51°. 7, which certainly:is a very wretched summer, and shows how little bright sunshine there can be. |