ne their
structure, and note the temperature of the dew point particularly.

"Shortly it becomes lighter, the light gradually increasing, till it is
succeeded by a flood of light, at first striking, then dazzling, and we
pass out of the dense cloud to where the clouds open out in bold and
fantastic shapes, showing us light and shadow, and spectral scenes, with
prismatic embellishments, disporting themselves around us in wild
grandeur, till at length we break out into brilliant sunshine, and the
clouds roll away in a perfect sea of vapour, obscuring the earth
entirely; so that now in perfect silence I note the circumstances, and
make my observations for some time uninterruptedly.

"After a time Mr Coxwell directs my attention to the fact that the
balloon is full, and that the gas is coming out from the safety-valve.
I of course look, for this is an exciting moment. He then directs my
attention to the fit and proportions of the netting. I find the gas,
which was before cloudy and opaque, is now clear and transparent, so
that I can look right up the balloon and see the meshes of the net-work
showing through it, the upper valve with its springs and line reaching
to the car, and the geometrical form of the balloon itself. Nor is this
an idle examination. I have already said that, in passing through the
cloud, the netting would gather moisture, augmenting the weight of the
balloon. If this should not all have evaporated, the net-work would
have become frozen, and be a wire-rope; so that, if the diamond shape of
the netting when under tension, and the form of the crown of the
balloon, be not symmetrical, the weight might not be equally
distributed, and there would be danger of it cutting the balloon. A
sense of security therefore follows such an examination.

"A stream of gas now continually issues from the neck, which is very
capacious, being fully two square feet in area, which is always left
open. Presently I see Mr Coxwell, whose eye has been continually
watching the balloon, pass his fingers over the valve-line, as if in
readiness to pull the cord. I observe a slight gathering on his brow,
and look inquiringly at him. He says, `I have decided upon opening the
large upper valve,' and carefully explains why. `The tension,' he says,
`in the balloon is not greater than it would bear with safety in a warm
stratum of air; but now that we are three miles up with a chilled
balloon, it is better to allow some to escape