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come to an end, and men could hope that it would last at least through another era. Those who could not attend the public ceremonies watched kneeling on the roofs of their houses. The secular festival was suppressed by the Spaniards, the last human victim having been sacrificed on the pyramid of Tlaloc in 1507.—Translated for the Popular Science Monthly from a review, by M. L. Barré, in the Revue Scientifique.

By A. H. ALMY.

IN the May number of this magazine a sketch was presented of the rise and progress of the beet-sugar industry. In this article it is proposed to outline the method of growing the plant, and the processes employed in extracting the sugar. The sugar-beet, like other plants, contains a definite number of chemical elements which are indispensable to its growth, and which must be present in suitable proportions in order to insure its highest development. Yet it is not long since the proportions of these constituents were looked upon as merely incidental, and without any direct bearing on the processes of growth. Plants are nourished by air, water, and the substances contained in the soil; but they differ in the kinds and quantities of nourishment required. Some need to have their roots constantly in water, others are best suited to dry soils, and others again prosper only on the best and most richly manured land. There are some elements common to all plants, and some peculiar to each kind. Like animals, plants are endowed with taste or choice regarding their food—they do not absorb indiscriminately nor in the same proportions all the substances presented to them. From this it follows that the fertilization of the soil should be adapted to the character of the plant that is to be cultivated. Wheat, rye, barley, and other cereals push up long stalks having few and slender leaves, which absorb little nourishment from the air. These plants consequently take most of their food through the roots, and are, therefore, great exhausters of the soil. Plants, on the contrary, having large, fleshy, green leaves, like the beet, take greater quantities of carbonic acid and water from the air, and hence withdraw less material from the ground. In the process of growth plants exhaust that portion of the soil which comes in contact with their roots; hence, after the surface layers have been drawn upon by short, creeping roots like those of the cereals, a long tap-root, like that of the beet, may be able to extract an abundance of nourishment from the deeper