wards, beyond the orbit of Venus at least, and I believed indefinitely farther.[1] Indeed, this medium I could not suppose confined to the path of the comet's ellipse, or to the immediate neighborhood of the sun. It was easy, on the contrary, to imagine it pervading the entire regions of our planetary system, condensed into what we call atmosphere at the planets themselves, and perhaps at some of them modified by considerations purely geological; that is to say, modified, or varied in its proportions (or absolute nature) by matters volatilized from the respective orbs.
Having adopted this view of the subject, I had little farther hesitation. Granting that on my passage I should meet with atmosphere essentially the same as at the surface of the earth, conceived that, by means of the very ingenious apparatus of M. Grimm, I should readily be enabled to condense it in sufficient quantity for the purposes of respiration. This would remove the chief obstacle in a journey to the moon. I had indeed spent some money and great labor in adapting the apparatus to the object intended, and confidently looked forward to its successful application, if I could manage to complete the voyage within any reasonable period.—This brings me back to the rate at which it would be possible to travel.
It is true that balloons, in the first stage of their ascensions from the earth, are known to rise with a velocity comparatively moderate. Now, the power of elevation lies altogether in the superior gravity of the atmospheric air compared with the gas in the balloon; and, at first sight, it does not appear probable that, as the balloon acquires altitude, and consequently arrives successively in atmospheric strata of densities rapidly diminishing—I say, it does not appear at all reasonable that, in this its progress upward, the original velocity should be accelerated. On the other hand, I was not aware that, in any recorded ascension, a diminution had been proved to be apparent in the absolute rate of ascent; although such should have been the case, if on account of nothing else, on account of the escape of gas through balloons ill-constructed, and varnished with no better material than the ordinary varnish. It
- ↑ The zodiacal light is probably what the ancients called Trabes. Emicant Trabes quos docos vocant.—Pliny lib. 2, p. 26.
