These bridges, in fact, are the origin of our chain or suspension bridges, but the elastic and light nature of the rushes makes the motion of the bridge very unpleasant. Indeed when I had one day gone about half way across one of them, my head began to swim, and I was obliged to sit down to recover myself; for I really thought I should never reach the opposite side. I sat there for some time, swinging in a most perilous yet ridiculous situation I assure you. I wished much to see the interior of one of the mines, but they were too far off. The quicksilver mines of Huancavelica is particularly curious, having a complete town and its cathedral deep in the bowels of the earth. I shall not attempt to tell you half the dangers, difficulties, and troubles I have met with. I made the sun my guide by day, and the stars by night. I roosted in trees, like the birds, and ate fruit and herbs like the beast. I explored mountain torrents, which no human beings, probably, had never seen before; found diamonds in their beds, which had been dried up; collected gold from the mud of the rivers, and a great many curiosities, which I was obliged to throw away, for want of convenience to carry them. I met with tribes of Indians who had never heard of the name of England, or seen an Englishman. FOOTNOTES: [1] This part of the story may seem a little unnatural, but many travellers make similar statements. VISIT TO A CAVERN. Visit to a Cavern—The Guacharos—Night sounds—Return—An alarm—My escape—Thanks for deliverance. One evening, during my journey, having refreshed myself with some of the fruit that grew near me—for I always found food enough in South America, even in the forests—I took a fancy to explore a cavern that I saw in the rock, near which a cascade tumbled. Resolving to be well prepared for any enemy I might meet with, I took my gun with me. I ought to tell you, by the way, that after I lost my mule, I was obliged for some time to content myself with a horse. I left him grazing at the foot of a bark tree. You have heard of the Peruvian bark, which is used so much in medicine, I dare say. I tied my horse, then, to a tree, which produces this sort of bark. Well, all things prepared, I set out on my expedition. As I drew near the lofty cavern, I was astonished at the deafening noise of innumerable wings, and looking up in the uncertain twilight, I saw hundreds—I think I might say thousands—of birds flying about, preparing to leave their home, in search of food. They were the _guacharos_. I had read of them in Humboldt’s narrative, but to use the sailor phrase, I had never before ‘run foul’ of any of them. They are night birds, that somewhat resemble our owls, but instead of roosting on trees, these creatures build in caverns. A sight of them is well worth the trouble and danger of exploring one of these dark and gloomy mansions. Their noise is prodigious!