The Peruvian farmers were well acquainted with the different kinds of manures, and made large use of them; a circumstance rare in the rich lands of the tropics, and probably not elsewhere practised by the rude tribes of America. They made great use of guano, the valuable deposit of sea-fowl, that has attracted so much attention, of late, from the agriculturists both of Europe and of our own country, and the stimulating and nutritious properties of which the Indians perfectly appreciated. This was found in such immense quantities on many of the little islands along the coast, as to have the appeaarnce of lofty hills, which, covered with a white saline incrustation, led the Conquerors to give them the name of the sierra nevada, or "snowy mountains." The Incas took their usual precautions for securing the benefits of this important article to the husbandman. They assigned the small islands on the coast to the use of the respective districts which lay adjacent to them. When the island was large, it was distributed among several districts, and the boundaries for each were clearly defined. All encroachment on the rights of another was severely punished. And they secured the preservation of the fowl by penalties as stern as those by which the Norman tyrants of England protected their own game. No one was allowed to set foot on the island during the season for breeding, under pain of death; and to kill the birds at any time was punished in the like manner.24 With this advancement in agricultural science, the Peruvians might be supposed to have had some knowledge of the plough, in such general use among the primitive nations of the eastern continent. But they had neither the iron ploughshare of the Old World, nor had they animals for draught, which, indeed, were nowhere found in the New. The instrument which they used was a strong, sharp-pointed stake, traversed by a horizontal piece, ten or twelve inches from the point, on which the ploughman might set his foot and force it into the ground. Six or eight strong men were attached by ropes to the stake, and dragged it forcibly along, --pulling together, and keeping time as they moved by chanting their national songs, in which they were accompanied by the women who followed in their-train, to break up the sods with their rakes. The mellow soil offered slight resistance; and the laborer., by long practice, acquired a dexterity which enabled him to turn up the ground to the requisite depth with astonishing facility. This substitute for the plough was but a clumsy contrivance; yet it is curious as the only specimen of the kind among the American aborigines, and was perhaps not much inferior to the wooden instrument introduced in its stead by the European conquerors .25