The total extent of the cavern is unknown; though the guides assert that it ends in the gallery of the organ-pipes, there are indications that the statement is false. These indications are: the air, which, even at such profound depths, is perfectly respirable; the lack of exploration; the superstitious fears of the guides to go further; and, some traditions, which declare that new galleries exist and have been explored by persons, who report a rushing torrent producing a terrible noise, for which reason no one cares to penetrate further. But, although the extent of the cavern is unknown and the gallery of the organ-pipes may not be the last, we ought not to believe the reports, which give the cavern immense extension. For example, some say that the galleries and ramifications extend to the mountains of Tasco, and there is one tradition, which affirms that the cavern prolongs itself, through the interior of the mountains which limit the Valley of Mexico on the south, until it unites with the cavern of Teutli, near Milpa Alta. This tradition, although improbable, is curious; it states that some families hid their treasure in the cave which occurs in the mountain of Teutli; this has a very narrow entrance at first, but after some twelve or fifteen metres broadens, forming a most beautiful cavern; this cavern has a series of chambers, of greater or lesser size, which finally communicate with the cave of Cacahuamilpa, more than one hundred kilometres distant. The tradition cited adds that but few persons have dared to penetrate the cave of Teutli, and on but one occasion, a herd of sheep having entered it, some peons followed to collect and bring them out--a thing they could not do because the animals penetrated far into the cave; those who went in pursuit of them returned after two days of journeying through these rough passages. In conclusion, it only remains to state, that the existence of the cavern of Cacahuamilpa remained unknown to everyone, until the year 1833. Before that year, not even the Indians had entered it, because they believed that the stalagmite in the form of a goat was a bad spirit, that guarded the mysteries, which the cavern enclosed; but a criminal who took refuge in it and was there during the period of his pursuit, after which he returned to his home, astonished the inhabitants of Tetecala by his fantastic reports; they made the first exploration and announced their expedition, describing the wonderful cavern. Since then, until now, expeditions have not lacked; unhappily, none of them has been scientific. ANTONIO GARCÍA CUBAS. [Illustration]