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.