The canal which unites the lakes of Texcoco and Xochimilco in the days of Spring is to be seen covered with canoes loaded with flowers and vegetables bound for the city markets; and everyone, who has participated in the Lenten festivities of the Viga, will ever remember, with delight, the animation that constantly reigns in that place, where the common people finds its greatest joy. It may be said that there is the place of the festival of Spring and flowers. * * * * * Summer, in the Valley, as the other seasons of the year, has its especial attractiveness. The atmospheric strata being unequally expanded by the fierce heat from the earth’s surface, the order or arrangement of the layers in contact with the soil is, so to say, inverted. It is well known that the lower layers of air have the greater density, from the fact that the upper layers weigh down upon them; from the earth’s surface upward there is a gradual decrease in density until the last, the lightest and most subtle, which is called ether. This general law being interfered with by the expansion of the lower layers, refraction of the light rays,--or the deviation which they suffer in passing from one medium into another of differing density--takes place in a manner contrary to that when the atmospheric layers are normally superposed, and the mirage[1] is produced, an optical illusion, which causes us to see objects, below the horizon or in the air, inverted. In the dry and level stretches in the north of the Valley, one frequently sees the thick vapor stretch itself out over the surface of the ground, and upon it, inverted, are portrayed the mountains with all their irregularities and details, as if reproduced in a limpid mirror of waters. The mirage is yet more interesting, more wonderful, in the Lake of Texcoco, though the phenomenon is there less frequent. On clear days, from the shore, one sees the full extent of the lake and the tranquillity of its water. Miserable, frail canoes, the form of which has not varied since the days of the conquest, are seen crossing the lake, loaded with grains and vegetables for the Mexican markets. The unsteady and narrow _chalupas_ of the fishermen and flower-dealers rapidly cleave the watery surface and only the creaking of the oars, or the notes of the monotonous songs of the boatmen break the silence of the solitude. When the temperature of the water of the lake is less than that of the air with which it is in contact, those little crafts suddenly disappear from the surface of the water and are seen, inverted, floating in the air, coursing to the stroke of the oars, through a shifting sea of clouds. JOAQUÍN GARCÍA ICAZBALCETA. [Illustration]