Scientific Ascents. Ascent of M. Sacharof.
We come now to an account of the use to which the balloons has been applied for the advancement of science. The ascents that have been made are by Sacharof, Biot, and Gay-Lussac in 1804, by Bixio and Barral in 1850, by Mr. Welsh in 1852, by Mr. Glaisher in 1862-66, and MM. Flammarion and De Fonvielle in 1867-68. We shall give a brief account of these ascents, because, as has been remarked, with a few exception, they form the only useful purpose to which the balloon has been applied. The general description of the phenomena, &c., met with in a high ascent, and the general results found, are referred to in the account of Mr. Glaisher's experiments, as not only are his accounts more detailed, but the number of ascents made by him is much in excess of that of all the others put together.
The Academy of Sciences at St Petersburg, entertaining the opinion that the experiments made on mountain-sides by De Luc, De Saussure, Humboldt, and others must give results different from those made in free air at the same heights, resolved in 1803 that a balloon ascent should be made for the purpose of making scientific researches. Accordingly, on January 30, 1804, M. Sacharof, a member of the academy, ascended, with M. Robertson as aeronaut, in a balloon belonging to the latter, which was inflated with hydrogen gas. The ascent was made at a quarter past seven, and the descent effected at a quarter to eleven. No great height was reached, as the barometer never sank below 23 in., corresponding to les than 1 1/2 mile. The experiments were not very systematically made, and the chief results were the filling and bringing down several flasks of air collected at different elevations, and the supposed observation that the magnetic dip was altered. A telescope was fixed in the bottom of the car pointing vertically downwards, so that the travelers might be able to ascertain exactly the spot over which they were floating at any moment. M. Sacharof found that, on shouting downwards through his speaking --trumpet, the echo from the earth was quite distinct, and at his height was audible after an interval of about ten seconds. M. Sacharof's account is given in the Philosophical Magazine (Tilloch's), vol. xxi. pp. 193-200 (1805).
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