lives of his companions, who stand in need of all the
available weight and help that the car contains up to the moment Of
coming to final rest.

We have already touched on the early notions as to the means of steering
a balloon. Oars had been tested without satisfactory result, and the
conception of a rotary screw found favour among theorists at this time,
the principle being actually tried with success in working models,
which, by mechanical means, could be made to flit about in the still
air of the lecture room; but the only feasible method advocated was that
already alluded to, which depended on the undesirable action of a trail
rope dragging over the ground or through water. The idea was, of course,
perfectly practical, and was simply analogous to the method adopted
by sailors, who, when floating with the stream but without wind, are
desirous of gaining "steerage way." While simply drifting with the
flood, they are unable to guide their vessel in any way, and this, in
practice, is commonly effected by simply propelling the vessel faster
than the stream, in which case the rudder at once becomes available. But
the same result is equally well obtained by slowing the vessel, and this
is easily accomplished by a cable, with a small anchor or other weight
attached, dragging below the vessel. This cable is essentially the same
as the guide-rope of the older aeronauts.

It is when we come to consider the impressions and sensations described
by sky voyagers of bygone times that we find them curiously at variance
with our own. As an instance, we may state that the earth, as seen from
a highflying balloon, used to be almost always described as appearing
concave, or like a huge basin, and ingenious attempts were made to prove
mathematically that this must be so. The laws of refraction are brought
in to prove the fact; or, again, the case is stated thus: Supposing the
extreme horizon to be seen when the balloon is little more than a mile
high, the range of view on all sides will then be, roughly, some eighty
miles. If, then, a line were drawn from the aerial observer to this
remote distance, that line would be almost horizontal; so nearly so that
he cannot persuade himself that his horizon is otherwise than still on
a level with his eye; yet the earth below him lies, as it seems, at the
bottom of a huge gulf. Thus the whole visible earth appears as a vast
bowl or basin. This is extremely ingenious reasoning, and not to be
disre