Equinoctial Regions of America, vol 2 | Page 8

these countries to fix columns of granite in the basin itself, in order to observe from year to year the mean height of the waters. The Marquis del Toro has undertaken to put this design into execution, employing the fine granite of the Sierra de Mariara, and establishing limnometers, on a bottom of gneiss rock, so common in the lake of Valencia.
It is impossible to anticipate the limits, more or less narrow, to which this basin of water will one day be confined, when an equilibrium between the streams flowing in and the produce of evaporation and filtration, shall be completely established. The idea very generally spread, that the lake will soon entirely disappear, seems to me chimerical. If in consequence of great earthquakes, or other causes equally mysterious, ten very humid years should succeed to long droughts; if the mountains should again become clothed with forests, and great trees overshadow the shore and the plains of Aragua, we should more probably see the volume of the waters augment, and menace that beautiful cultivation which now trenches on the basin of the lake.
While some of the cultivators of the valleys of Aragua fear the total disappearance of the lake, and others its return to the banks it has deserted, we hear the question gravely discussed at Caracas, whether it would not be advisable, in order to give greater extent to agriculture, to conduct the waters of the lake into the Llanos, by digging a canal towards the Rio Pao. The possibility* of this enterprise cannot be denied, particularly by having recourse to tunnels, or subterranean canals. (The dividing ridge, namely, that which divides the waters between the valleys of Aragua and the Llanos, lowers so much towards the west of Guigue, as we have already observed, that there are ravines which conduct the waters of the Cano de Cambury, the Rio Valencia, and the Guataparo, in the time of floods, to the Rio Pao; but it would be easier to open a navigable canal from the lake of Valencia to the Orinoco, by the Pao, the Portuguesa, and the Apure, than to dig a draining canal level with the bottom of the lake. This bottom, according to the sounding, and my barometric measurements, is 40 toises less than 222, or 182 above the surface of the ocean. On the road from Guigue to the Llanos, by the table-land of La Villa de Cura, I found, to the south of the dividing ridge, and on its southern declivity, no point of level corresponding to the 182 toises, except near San Juan. The absolute height of this village is 194 toises. But, I repeat that, farther towards the west, in the country between the Cano de Cambury and the sources of the Rio Pao, which I was not able to visit, the point of level of the bottom of the lake is much further north.) The progressive retreat of the waters has given birth to the beautiful and luxuriant plains of Maracay, Cura, Mocundo, Guigue, and Santa Cruz del Escoval, planted with tobacco, sugar-canes, coffee, indigo, and cacao; but how can it be doubted for a moment that the lake alone spreads fertility over this country? If deprived of the enormous mass of vapour which the surface of the waters sends forth daily into the atmosphere, the valleys of Aragua would become as dry and barren as the surrounding mountains.
The mean depth of the lake is from twelve to fifteen fathoms; the deepest parts are not, as is generally admitted, eighty, but thirty-five or forty deep. Such is the result of soundings made with the greatest care by Don Antonio Manzano. When we reflect on the vast depths of all the lakes of Switzerland, which, notwithstanding their position in high valleys, almost reach the level of the Mediterranean, it appears surprising that greater cavities are not found at the bottom of the lake of Valencia, which is also an Alpine lake. The deepest places are between the rocky island of Burro and the point of Cana Fistula, and opposite the high mountains of Mariara. But in general the southern part of the lake is deeper than the northern: nor must we forget that, if all the shores be now low, the southern part of the basin is the nearest to a chain of mountains with abrupt declivities; and we know that even the sea is generally deepest where the coast is elevated, rocky, or perpendicular.
The temperature of the lake at the surface during my abode in the valleys of Aragua, in the month of February, was constantly from 23 to 23.7 degrees, consequently a little below the mean temperature of the air. This may be from the effect of evaporation, which carries off caloric from the air and the water; or because