"As I desired to test Humboldt's altitude, I had taken the precaution to be as well prepared as circumstances would admit, and accordingly had carried with me the best barometer I could get, which, from previous calculations, I deemed capable of indicating a height of from 300 to 400 feet higher than that given by him. I had, also, provided myself with a spirit-lamp and thermometer, for the purpose of taking the temperature of boiling water; but, on the march, the bottle containing the alcohol was broken and the spirit entirely lost. I therefore determined to test the combustible qualities of whiskey. One of my first objects after reaching the summit was to make observations; but, on preparing the barometer, the mercury sank at once _below_ the graduation. "I estimated the distance between the lowest line of graduation and the top of the mercury at two-tenths of an inch, which gives,--with corresponding observations in the city of Orizaba at the same hour,--an elevation of 17,907 feet, and makes it the highest point on the North American Continent. I do not think I could have been far wrong in my estimate, as the means of comparison were before me; but, even supposing I was mistaken one-twentieth of an inch, we still have an elevation of 17,819 feet, 98 feet higher than Popocatepetl, which is usually considered the highest point,--5,400 metres, or, 17,721 feet, as given by Humboldt.[51] The temperature was just below freezing point. My attempt to burn whiskey failed. Since my return to the United States, I have observed that Humboldt states that Mr. Ferrar measured Orizaba, eight years before his arrival in Mexico, and gave the mountain an elevation of 5,460 metres or 17,885 feet. Humboldt's measurement, made from a plain near Jalapa, is 155 metres less, or 17,377 feet in all. It will be seen that my determination agrees very nearly with that of Mr. Ferrar. * * * * * "We remained on the summit about an hour,--planted our national banner and saluted it with three hearty cheers. The day was clear, but the atmosphere thick and smoky, so that we did not enjoy the views we had hoped for; but as we believed ourselves to have been the first who ever looked into the crater, we were amply repaid for our trouble. "The descent was by no means so difficult as the ascent; a slide on the snow or sand carried us hundreds of feet down a space which had required many weary steps to ascend. About dark we arrived at our encampment, highly delighted with our trip, though much exhausted. All who made the final attempt were more or less affected either with violent headaches, nausea, and vomiting, or bleeding at the nose. The veils which we provided for our journey did good service, but the face, and particularly the lips, of all who reached the summit, became so extremely swollen and cracked as to confine them to their rooms for several days.