And this, I am inclined to believe, was the real condition of things in the time of Cortez. The city of Mexico alone would have exhausted the limited resources of the valley. Old Thomas Gage was as much puzzled two hundred years ago to account for this astonishing disappearance of the numerous Indian cities of this valley as we are, and also for the supposed filling up of the lakes, never appearing to suspect that the story of Cortez was a fiction. [31] There has been much speculation in regard to the origin of the saline properties of this water; but the Artesian borings going on while I was in Mexico, I think, sufficiently demonstrate that the earthy bottom of the valley, for hundreds of feet, contains an infusion of carbonate and muriate of soda. [32] The atmosphere of Mexico is so intensely dry, that the hygrometer of Deluc frequently descends to 15 deg..--HUMBOLDT'S _Essai Politique_, vol. ii. p. 110. [33] When the Artesian well, in process of construction near my residence, had reached a depth of seventy yards, the water that came up was slightly impregnated with this salt. [34] _Comercio de Mexico_, 1852. CHAPTER XVI. The Chinampas or Water Gardens.--Laws of Nature not set aside.--Mud will not float.--The present Chinampas.--They never could have been floating Gardens.--Relations of the Chinampas to the ancient State of the Lake in the Valley. All the world has heard of the floating gardens (_chinampas_) of Mexico, but all the world has not seen them. I have not seen any floating gardens, nor, on diligent inquiry, have I been able to find a man, woman, or child that ever has seen them, nor do I believe that such a thing as a floating garden ever existed at Mexico. Humboldt admits that they do exist; says that he has seen floating earthy masses of great size in the tropical rivers, and then describes the manner of the construction of the chinampas, but in such a way as to satisfy the careful reader that he does not intend to say that he saw them himself, and evidently makes his statement upon hearsay; and takes it up as an admitted fact, without having his mind called to the physical impossibilities of floating a mass of earth that was of a greater specific gravity than water. FAITH AND TESTIMONY.