ct of the sky. Suddenly everything disappeared except a
brilliant rainbow at some little distance--or perhaps I should rather
have said a halo of more than ordinary rainbow brilliancy, since it
occupied, not like the rainbows seen from below, something less than
half, but nearly two-thirds of a circle. I was, of course, aware that
I was passing through a cloud, and one of very unusual thickness. In a
few seconds, however, I was looking down upon its upper surface,
reflecting from a thousand broken masses of vapour at different
levels, from cavities and hillocks of mist, the light of the sun;
white beams mixed with innumerable rays of all colours in a confusion,
of indescribable brilliancy. I presume that the total obscuration of
everything outside the cloud during my passage through it was due to
its extent and not to its density, since at that height it could not
have been otherwise than exceedingly light and diffuse. Looking upward
through the eastern window, I could now discern a number of brighter
stars, and at nearly every moment fresh ones came into view on a
constantly darkening background. Looking downward to the west, where
alone the entire landscape lay in daylight, I presently discerned the
outline of shore and sea extending over a semicircle whose radius much
exceeded five hundred miles, implying that I was about thirty-five
miles from the sea-level. Even at this height the extent of my survey
was so great in comparison to my elevation, that a line drawn from the
vessel to the horizon was, though very roughly, almost parallel to the
surface; and the horizon therefore seemed to be not very far from my
own level, while the point below me, of course, appeared at a vast
distance. The appearance of the surface, therefore, was as if the
horizon had been, say, some thirty miles higher than the centre of the
semicircle bounding my view, and the area included in my prospect had
the form of a saucer or shallow bowl. But since the diameter of the
visible surface increases only as the square root of the height, this
appearance became less and less perceptible as I rose higher. It had
taken me twenty minutes to attain the elevation of thirty-five miles;
but my speed was, of course, constantly increasing, very much as the
speed of an object falling to the Earth from a great height increases;
and before ten more minutes had elapsed, I found myself surrounded by
a blackness nearly absolute, except in the direction of the
Sun