chisels upon the very stone it had evidently been once used to cut, and found that its edge was turned directly; and therefore he wonders that such a tool could have been used for the purpose, of course supposing that the tool as he found it was just as the mason left it. This, however, is not quite certain. If we bury a brass tool in a damp place for a few weeks, it will be found to have undergone a curious molecular change, and to have become quite soft and weak, or, as the workmen call it, dead. We ought to be quite sure whether lying for centimes under ground may not have made some similar change in bronze.
I have seen many prickly pears in different places, but never such specimens as those that were growing among the stones in this old quarry. They had gnarled and knotted trunks of hard wood, and were as big as pollard-oaks; their age must have been immense; but, unfortunately, one could not measure it, or it would have been a good criterion of the age of the quarry, which had not only been excavated but abandoned before their time. In one of the caves was a human skeleton, blanched white and clean, and near it some one has stuck a cross, made of two bits of stick, in the crevices of a heap of stones.
Returning to the entrance of the quarry, well loaded with stone hammers and knives, we sat down to breakfast, in a cave, where our man had established himself with the horses. An attempt on my part to cut German sausage with an obsidian knife proved a decided failure.
We had already been struck by the appearance of the two pyramids of Teotihuacán, when we passed by Otumba on our way to Mexico. The hills which skirt the plain are so near them as to diminish their apparent size; but even at a distance they are conspicuous objects. Now, when we came close to them, and began by climbing to their summits, and walking round their terraces, to measure ourselves against them, we began gradually to realize their vast bulk; and this feeling continually grew upon us.