At six o'clock, I perceived a great portion of the earth's visible area to the eastward involved in thick shadow, which continued to advance with great rapidity, until, at five minutes before seven, the whole surface in view was enveloped in the darkness of night. It was not, however, until long after this time that the rays of the setting sun ceased to illumine the balloon; and this circumstance, although of course fully anticipated, did not fail to give me an infinite deal of pleasure. It was evident that, in the morning, I should behold the rising luminary many hours at least before the citizens of Rotterdam, in spite of their situation so much farther to the eastward, and thus, day after day, in proportion to the height ascended, would I enjoy the light of the sun for a longer and a longer period. I now determined to keep a journal of my passage, reckoning the days from one to twenty-four hours continuously, without taking into consideration the intervals of darkness.

At ten o'clock, feeling sleepy, I determined to lie down for the rest of the night; but here a difficulty presented itself, which, obvious as it may appear, had escaped my attention up to the very moment of which I am now speaking. If I went to sleep as I proposed, how could the atmosphere in the chamber be regenerated in the interim? To breathe it for more than an hour, at the farthest, would be a matter of impossibility, or, if even this term could be extended to an hour and a quarter, the most ruinous consequences might ensue.

The consideration of this dilemma gave me no little disquietude; and it will hardly be believed, that, after the dangers I had undergone, I should look upon this business in so serious a light, as to give up all hope of accomplishing my ultimate design, and finally make up my mind to the necessity of a descent. But this hesitation was only momentary. I reflected that man is the 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 arranged all this, the rest of the plan is obvious. My bed was so contrived upon the floor of the car, as to bring my head, in lying down, immediately below the mouth of the pitcher. It was evident, that, at the expiration of an hour, the pitcher, getting full, would be forced to run over, and to run over at the mouth, which was somewhat lower than the rim. It was also evident, that the water thus falling from a height of more than four feet, could not do otherwise than fall upon my face, and that the sure consequences would be, to waken me up instantaneously, even from the soundest slumber in the world.

It was fully eleven by the time I had completed these arrangements, and I immediately betook myself to bed, with full confidence in the efficiency of my invention. Nor in this matter was I disappointed.

Punctually every sixty minutes was I aroused by my trusty chronometer, when, having emptied the pitcher into the bung-hole of the keg, and performed the duties of the condenser, I retired again to bed. These regular interruptions to my slumber caused me even less discomfort than I had anticipated; and when I finally arose for the day, it was seven o'clock, and the sun had attained many degrees above the line of my horizon.

April 3d. I found the balloon at an immense height indeed, and the earth's apparent convexity increased in a material degree. Below me in the ocean lay a cluster of black specks, which undoubtedly were islands. Far away to the northward I perceived a thin, white, and exceedingly brilliant line, or streak, on the edge of the horizon, and I had no hesitation in supposing it to be the southern disk of the ices of the Polar Sea. My curiosity was greatly excited, for I had hopes of passing on much farther to the north, and might possibly, at some period, find myself placed directly above the Pole itself. I now lamented that my great elevation would, in this case, prevent my taking as accurate a survey as I could wish. Much, however, might be ascertained. Nothing else of an extraordinary nature occurred during the day. My apparatus all continued in good order, and the balloon still ascended without any perceptible vacillation. The cold was intense, and obliged me to wrap up closely in an overcoat. When darkness came over the earth, I betook myself to bed, although it was for many hours afterward broad daylight all around my immediate situation. The water-clock was punctual in its duty, and I slept until next morning soundly, with the exception of the periodical interruption.

April 4th. Arose in good health and spirits, and was astonished at the singular change which had taken place in the appearance of the sea. It had lost, in a great measure, the deep tint of blue it had hitherto worn, being now of a grayish-white, and of a lustre dazzling to the eye. The islands were no longer visible; whether they had passed down the horizon to the southeast, or whether my increasing elevation had left them out of sight, it is impossible to say. I was inclined, however, to the latter opinion. The rim of ice to the northward was growing more and more apparent. Cold by no means so intense. Nothing of importance occurred, and I passed the day in reading, having taken care to supply myself with books.