This little town of Pachuca has long been a place of some importance in the world, as regards mining-operations. The Aztecs worked silver-mines here, as well as at Tasco, long before the Spaniards came, and they knew how to smelt the ore. It is true that, if no better process than smelting were known now, most of the mines would scarcely be worth working; but still, to know how to extract silver at all was a great step; and indeed at that time, and for long after the Conquest, there was no better method known in Europe. It was in this very place that a Spaniard, Medina by name, discovered the process of amalgamation with mercury, in the year 1557, some forty years after the invasion. We went to see the place where he first worked his new process, and found it still used as a “hacienda de beneficio” (establishment for extracting silver from the ore.) So few discoveries in the arts have come out of Mexico, or indeed out of any Spanish colony, that we must make the most of this really very important method, which is more extensively used than any other, both in North and South America. As for the rest of the world, it produces, comparatively, so little silver, that it is scarcely worth taking into account. We had forgotten, when we went to bed, that we were nearly seven hundred feet higher than Mexico; but had the fact brought to our remembrance by waking in the middle of the night, feeling very cold, and finding our thermometer marking 40 degrees Fahr.; whereupon we covered ourselves with cloaks, and the cloaks with the strips of carpet at our bedsides, and went to sleep again. We had hired, of the French landlord, two horses and a mozo to guide us, and sorry hacks they were when we saw them in the morning. It was delightful to get a little circulation into our veins by going at the best gallop our horses would agree to; for we were fresh from hot countries, and not at all prepared for having our hands and feet numbed with cold, and being as hoarse as ravens—for the sore throat which is the nuisance of the district, and is very severe upon new comers, had not spared us. Evaporation is so rapid at this high altitude that if you wet the back of your hand it dries almost instantly, leaving a smart sensation of cold. One may easily suppose, that when people have been accustomed to live under the ordinary pressure of the air, their throats and lungs do not like being dried up at this rate; besides their having, on account of the rarity of the air, to work harder in breathing, in order to get in the necessary quantity of oxygen. Coughs seem very common here, especially among the children, though people look strong and healthy, but in the absence of proper statistics one cannot undertake to say whether the district is a healthy one or not.