Chapter IV: Front Matter (4)

In compliance with the request of several philosophers of Paris, who were anxious that the same observations should be repeated at the greatest height that could be reached, Gay Lussac alone made a second ascent, on the morning of September 15, 1804, from the garden of the Repository of Models, and rose, by a gradual ascent, to a great elevation. He continued to take observations at short intervals of the state of the barometer, the thermometer, and the hygrometer, of which he has given a tabular view, but he unfortunately neglected to mark the time at which they were made--a point of material importance, for the results would of course be modified by the progress of the day; and it would have added to their value, had these observations been compared with similar ones made at the same time at the observatory. During the ascent of the balloon, the hygrometer was variable, but obviously marked an increase of dryness; the thermometer indicated a decrease in the heat of the atmosphere, but the decrease is not uniform, the ratio being higher in the elevated regions than in the lower, which are heated from the earth; and it was found, by not fewer than fifteen trials at different altitudes, that the oscillations of a finely-suspended needle varied very little from its oscillations on the surface of the earth. At the height of 21,460 feet. Lussac admitted the air into one of his exhausted flasks, and at the height of 21,790 feet, he filled the other. He continued to rise, till he was 22,912 feet above Paris, or 23,040 feet--that is upward of four miles and a quarter--above the level of the sea, the utmost limit of his ascent, an elevation not much below the summit of Nevado de Sorato, the highest mountain of America, and the loftiest peak of the Himalaya in Asia, the highest mountains in the world, and far above that to which any mortal had ever soared before. One can not but admire the intrepid coolness with which Lussac performed his experiments at this enormous elevation, conducting his operations with the same composure and precision as if he had been seated in his own parlor in Paris. Though warmly clad, he now began to suffer from the excessive cold, his pulse was quickened, he was oppressed by difficulty in breathing, and his throat became parched, from inhaling the dry, attenuated air--for the air was now more than twice as thin as ordinary, the barometer having sunk to 12.95 inches--so that he could hardly swallow a morsel of bread. He alighted safely, at a quarter before four o'clock afternoon, near the hamlet of St. Gourgan, about sixteen miles from Rouen. On reaching Paris, he hastened to the laboratory of the Polytechnic School, to analyze the air he had brought down in his flasks from the higher regions; and, by a very delicate analysis, it was found to contain exactly the same proportions as the air on the surface of the earth, every 1000 parts holding 215 of oxygen, confirming the identity of the atmosphere in all situations. The ascents of these two philosophers are memorable, as the first which were made for purely scientific purposes.

[From the Dublin University Magazine.]

MAURICE TIERNAY, THE SOLDIER OF FORTUNE

_(Continued from Vol. I. Page 797.)_