I conceived that the diameter of the congeries, measured in the direction of my path, which seemed to be nearly in the diameter of their orbit, was about 180,000 miles, and probably the perpendicular depth was about the same.
I may mention here, though somewhat out of place, to avoid interrupting the narrative of my descent upon Mars, the only interesting incident that occurred during the latter days of my journey—the gradual passage of the Earth off the face of the Sun. For some little time after this the Earth was entirely invisible; but later, looking through the telescope adjusted to the lens on that side, I discerned two very minute and bright crescents, which, from their direction and position, were certainly those of the Earth and Moon, indeed could hardly be anything else.
Towards the thirtieth day of my voyage I was disturbed by the conflicting indications obtained from different instruments and separate observations. The general result came to this, that the discometer, where it should have indicated a distance of 333, actually gave 347. But if my speed had increased, or I had overestimated the loss by changes of direction, Mars should have been larger in equal proportion. This, however, was not the case. Supposing my reckoning to be right, and I had no reason to think it otherwise, except the indication of the discometer, the Sun's disc ought to have diminished in the proportion of 95 to 125, whereas the diminution was in the proportion of 92 to 122. So far as the barycrite could be trusted, its very minute indications confirmed those of the discometer; and the only conclusion I could draw, after much thought and
