Page:Memoir of a tour to northern Mexico.djvu/55

Rh class blongs the Rio del Norte, running from northwest to southeast through the State, and its two tributaries, the Rio Conchos and Pecos. The water-courses that run into the Pacific all have their origin in the Sierra Madre, and are the following: the San Miguel, Refugio, Moris, Papigochic, and Gila. Of the latter, the Gila, the State of Chihuahua claims only the sources flowing from the Sierra de Mogoyon, until they unite with the Rio de San Francisco, a distance of 27 leagues. The third class of rivers discharge themselves into those peculiar lakes without outlet, which I have mentioned already in passing lake Encinillas, above Chihuahua. The following rivers empty into such lakes: the Rio de Casas Grandes into lake Guzman; the San Buenaventura into lake Santa Maria: and the Carmen into lake Patos. It appears as if those lakes are principally produced by the physical properties of the ground, to wit: a wide, very level plain and great porosity of the soil. Some of the lakes are supposed to have been formerly connected.

Common and mineral springs are very frequent in the State; the latter are mostly sulphurous, but are seldom used for medical purposes.

The climate generally is temperate. The influence of the more southern latitude of the State is counterbalanced by its high elevation above the sea. In the mountainous parts of the Sierra Madre, there is of course a greater variety in the seasons: hot summers, rainy seasons, and severe winters, often follow each other. But on the plains of the plateau, between 4,000 and 5,000 feet above the sea, there prevails a delightful, constant climate, with moderate temperature in summer and winter, with a clear sky and dry atmosphere, interrupted only by the rainy season, which generally lasts through July and August. The thermometer in the city of Chihuahua, I am told, seldom rises higher in the summer than about 95 degrees Fah., and of the moderate cold in the winter I can speak from experience. Some breezes prevail throughout the year. The barometer exhibits in the city of Chihuahua most regular daily oscillations, but very slight variations throughout the year. In the many observations which I have made there in the rainy season, in the winter and spring, there is a difference only between the highest and lowest stand of the mercurial column (reduced to 32° Fah.) of 0.580 inch.

The great dryness of the atmosphere produces, of course a very free development of electricity. By rubbing the hair of cats and dogs in the dark, I could elicit here a greater mass of electricity than I had ever seen produced in this way. Some persons, entitled to confidence, informed me that by changing their woollen under-dress in the night, they had at first been repeatedly frightened by seeing themselves suddenly enveloped in a mass of electrical fire. The remarkable flames that appeared after a thunder-storm in the mountains south of el Paso, already mentioned by me, were no doubt connected with electricity. I recollect also, from an account published in relation to the battle of Buena Vista, that during a sultry evening electrical flames were seen on the points of bayonets among the sentinels stationed in the mountains. Experiments made on the high table land of Mexico with a fine electrometer, would no doubt give interesting results. As to