veriest slave of custom, and that many points in the routine of his existence are deemed essentially important, which are only so at all by his having rendered them habitual.  It was very certain that I could not do without sleep; but I might easily bring myself to feel no inconvenience from being awakened at intervals of an hour during the whole period of my repose.  It would require but five minutes at most to regenerate the atmosphere in the fullest manner, and the only real difficulty was to contrive a method of arousing myself at the proper moment for so doing.  But this was a question which, I am willing to confess, occasioned me no little trouble in its solution.  To be sure, I had heard of the student who, to prevent his falling asleep over his books, held in one hand a ball of copper, the din of whose descent into a basin of the same metal on the floor beside his chair, served effectually to startle him up, if, at any moment, he should be overcome with drowsiness.  My own case, however, was very different indeed, and left me no room for any similar idea; for I did not wish to keep awake, but to be aroused from slumber at regular intervals of time.  I at length hit upon the following expedient, which, simple as it may seem, was hailed by me, at the moment of discovery, as an invention fully equal to that of the telescope, the steam-engine, or the art of printing itself.

“It is necessary to premise, that the balloon, at the elevation now attained, continued its course upward with an even and undeviating ascent, and the car consequently followed with a steadiness so perfect that it would have been impossible to detect in it the slightest vacillation whatever.  This circumstance favored me greatly in the project I now determined to adopt.  My supply of water had been put on board in kegs containing five gallons each, and ranged very securely around the interior of the car.  I unfastened one of these, and taking two ropes tied them tightly across the rim of the wicker-work from one side to the other; placing them about a foot apart and parallel so as to form a kind of shelf, upon which I placed the keg, and steadied it in a horizontal position.  About eight inches immediately below these ropes, and four feet from the bottom of the car I fastened another shelf —­ but made of thin plank, being the only similar piece of wood I had.  Upon this latter shelf, and exactly beneath one of the rims of the keg, a small earthern pitcher was deposited.  I now bored a hole in the end of the keg over the pitcher, and fitted in a plug of soft wood, cut in a tapering or conical shape.  This plug I pushed in or pulled out, as might happen, until, after a few experiments, it arrived at that exact degree of tightness, at which the water, oozing from the hole, and falling into the pitcher below, would fill the latter to the brim in the period of sixty minutes.  This, of course, was a matter briefly and easily ascertained, by noticing the proportion of the pitcher filled in any given time.  Having