scale, as the extent of surface, and consequent resistance of the air, increases in an immensely smaller proportion than the containing power, we may obtain an almost fabulous amount of ascensional force.  For instance:  a balloon of one hundred yards in diameter would suffice to raise only ten millions of pounds; but ten such balloons ranged one behind the other, or, better still, a cigar-shaped balloon, which would be equivalent to these ten balloons united in one (an arrangement which, as the law of development is similar for spheric and for cylindric bodies, would greatly diminish the resistance of the air, without occasioning any loss of containing power), would suffice to raise one hundred millions of pounds; and allowing some four or five millions of pounds for the weight of the vessel and its machinery, which, for a ship of this size—­supposing it were possible to make its various parts hold together—­should be, M. Petin computes, of twelve hundred horse-power, we should still have at command a surplus ascensional force of upwards of ninety millions of pounds; a force sufficient to sustain a body of fifty thousand men!

’In the construction of these enormous balloons, M. Petin proposes to substitute, in place of the silken bag hitherto used to contain the gas, a rigid envelope of a cylindro-conical form, composed of a series of metallic tubes, laid one above the other, and supplied with gas—­obtainable to any amount and almost instantaneously—­from the decomposition of water by a powerful electric battery; and with these resources at command, M. Petin conceives that balloons might be constructed on a scale even larger than that just given!

’In fact, this assumption of the possibility of obtaining command of an unlimited ascensional force has suggested, to certain enthusiastic partisans of M. Petin’s theory and plans, a long perspective of astounding visions, from which sober-minded Englishmen would, in all probability, turn away with derision.  These enthusiasts have evidently adopted the language of Archimedes, and are ready to exclaim:  “Give us a fulcrum, and,” with hydrogen gas as our lever, “we will move the world!”

’For ourselves, we have already stated the facts from which we derive our conviction that the conquest of the air, if achieved, is to be brought about through the agency of new and powerful mechanical combinations, rather than by means of the balloon; and though, as before remarked, the experiments of M. Petin and others may probably not be without useful results, we dismiss these brilliant phantasmagoria with the charitable reflection, that the extravagance of overweening hopefulness is, at least in an age which has witnessed the advent of steam and electricity, more natural and more pardonable than the scepticism of confirmed despondency; and that “he who shoots at the stars,” though missing his aim, will at all events shoot higher than he who aims at the mud beneath his feet.