My sleep was of necessity more or less broken. I wished to have eight hours of rest, since, though seven of continuous sleep might well have sufficed me, even if my brain had been less quiet and unexcited during the rest of the twenty-four, it was impossible for me to enjoy that term of unbroken slumber. I therefore decided to divide my sleep into two portions of rather more than four hours each, to be taken as a rule after noon and after midnight; or rather, since noon and midnight had no meaning for me, from 12h. to 16h. and from 24h. to 4.h. But of course sleep and everything else, except the necessary management of the machine, must give way to the chances of observation; it would be better to remain awake for forty-eight hours at a stretch than to miss any important phenomenon the period of whose occurrence could be even remotely calculated.
At 8h., I employed for the first time the apparatus which I may call my window telescope, to observe, from a position free from the difficulties inflicted on terrestrial astronomers by the atmosphere, all the celestial objects within my survey. As I had anticipated, the absence of atmospheric disturbance and diffusion of light was of extreme advantage. In the first place, I ascertained by the barycrite and the discometer my distance from the Earth, which appeared to be about 120 terrestrial radii. The light of the halo was of course very much narrower than when I first observed it, and its scintillations or coruscations no longer distinctly visible. The Moon presented an exquisitely fine thread of light, but no new object of interest on the very small portion of her daylight hemisphere turned towards me. Mars was somewhat difficult to observe, being too near what may be called my zenith. But the markings were far more distinct than they appear, with greater magnifying powers than I employed, upon the Earth. In truth, I should say that the various disadvantages due to the atmosphere deprive the astronomer of at least one-half of the available light-collecting power of his telescope, and consequently of the defining power of the eye-piece; that with a 200 glass he sees