"The moon's actual distance earth first thing attended to Now, the mean or average interval centres two planets is 59 9643 earth's equatorial radii, or only about 237,000 miles the mean or average interval But it borne in mind form moon's orbit being an ellipse of eccentricity amounting to no 0 05484 major semi-axis ellipse itself, earth's centre being situated in its focus, if , in any manner, contrive to meet the moon, as it were, in its perigee, the above mentioned distance materially diminished But, nothing at present possibility, very certain that, at all events, 237,000 miles to deduct the radius earth, say 4,000, radius moon, say 1080, in all 5,080, leaving an actual interval traversed, under average circumstances, of 231,920 miles Now this, I reflected, was no very extraordinary distance Travelling on land repeatedly accomplished rate of thirty miles per hour, and indeed much greater speed anticipated But even velocity, it would take me no more than 322 days to reach the surface moon There were, however, many particulars inducing me that my average rate of travelling might possibly exceed that of thirty miles per hour, and, considerations fail deep impression upon my mind, mention them more fully hereafter

"The next point regarded was matter of far greater importance From indications afforded barometer, that, in ascensions surface earth , height of 1,000 feet, left below us about one-thirtieth entire mass of atmospheric air, that at 10,600 ascended through nearly one-third; at 18,000, not far elevation of Cotopaxi, surmounted one-half the material, or, at all events, one-half the ponderable, body of air incumbent upon our globe also calculated that at an altitude not exceeding the hundredth part earth's diameter -- , not exceeding eighty miles -- the rarefaction so excessive that animal life could in no manner be sustained, and, moreover, most delicate means we possess of ascertaining the presence atmosphere inadequate to assure us existence But fail to perceive latter calculations are founded altogether experimental knowledge properties of air, mechanical laws regulating its dilation and compression, in what called, comparatively speaking, the immediate vicinity earth itself; and, same time, taken for granted that animal life is and essentially incapable of modification at any given unattainable distance surface Now, all such reasoning and from such data must, , be simply analogical The greatest height ever reached by man of 25,000 feet, attained aeronautic expedition of Messieurs Gay-Lussac and Biot moderate altitude, even when compared eighty miles ; and help thinking subject admitted room for doubt and great latitude for speculation

"But, in point of fact, an ascension being made to any given altitude, the ponderable quantity of air surmounted in any farther ascension is by no means in proportion additional height ascended (as plainly seen from stated before), but in ratio constantly decreasing therefore evident that, ascend as high as , , literally speaking, arrive at limit beyond which no atmosphere found It must exist, I argued; although it may exist in state of infinite rarefaction

" other hand, aware that arguments wanting the existence of real and definite limit atmosphere, beyond which absolutely no air whatsoever But circumstance been left out of view who contend for such limit seemed , although no positive refutation creed, still point worthy very serious investigation On comparing the intervals successive arrivals of Encke's comet at its perihelion, after giving credit, most exact manner, for all the disturbances due attractions planets, it appears periods are gradually diminishing; , the major axis comet's ellipse is growing shorter, in slow but perfectly regular decrease Now, precisely what the case, suppose resistance experienced comet from an extremely rare ethereal medium pervading the regions orbit is evident that such medium must, in retarding the comet's velocity, increase its centripetal, by weakening its centrifugal force In other words, the sun's attraction constantly attaining greater power, comet drawn nearer at every revolution Indeed, no other way of accounting variation But again The real diameter same comet's nebulosity is observed to contract rapidly as it approaches the sun, and dilate with equal rapidity in its departure towards its aphelion Was I not justifiable in supposing with M Valz, apparent condensation of volume has its origin compression same ethereal medium spoken of before, and only denser in proportion to its solar vicinity ? The lenticular-shaped phenomenon, also called the zodiacal light, was matter worthy of attention This radiance, so apparent tropics, and which mistaken for any meteoric lustre, extends horizon obliquely upward, and follows generally the direction sun's equator It appeared evidently nature of rare atmosphere extending sun outward, beyond the orbit of Venus , and I believed indefinitely farther {*2} Indeed, this medium suppose confined path comet's ellipse, or immediate neighborhood sun easy, contrary, to imagine it pervading the entire regions planetary system, condensed into what we call atmosphere planets themselves, and perhaps at modified by considerations, so , purely geological

Having adopted this view subject, I had little further hesitation Granting that on my passage meet with atmosphere essentially the same as surface earth, I conceived that, very ingenious apparatus of M Grimm, readily be enabled to condense it in sufficient quantity purposes of respiration remove the chief obstacle in journey moon I had indeed spent some money and great labor in adapting the apparatus object intended, and confidently looked forward to its successful application, if manage to complete the voyage within any reasonable period This brings me back rate at which it possible to travel

" true that balloons, first stage ascensions earth, are known to rise with velocity comparatively moderate Now, the power of elevation lies altogether superior lightness gas balloon compared atmospheric air; and, at first sight, it appear probable that, balloon acquires altitude, and consequently arrives successively in atmospheric strata of densities rapidly diminishing -- , it appear at all reasonable that, its progress upwards, the original velocity accelerated other hand, not aware that, in any recorded ascension, diminution was apparent absolute rate of ascent; although such the case, if on account of nothing else, on account escape of gas through balloons ill-constructed, and varnished with no better material ordinary varnish It seemed, therefore, effect escape was only sufficient to counterbalance the effect of some accelerating power I now considered that, provided in my passage the medium I had imagined, and provided should prove actually and essentially what we denominate atmospheric air, it could make comparatively little difference at what extreme state of rarefaction discover it -- , in regard to my power of ascending -- gas balloon only be itself subject to rarefaction partially similar (in proportion occurrence , suffer an escape of as requisite explosion), but, being what , would, at all events, continue specifically lighter than any compound whatever of mere nitrogen and oxygen meantime, the force of gravitation constantly diminishing, in proportion squares distances, and thus, with velocity prodigiously accelerating, arrive in those distant regions where the force earth's attraction superseded moon In accordance ideas, think it worth while to encumber myself with more provisions than sufficient for period of forty days