Free Across the Zodiac by Percy Greg

considerations that the course I henceforward steered was
determined. By a very simple calculation, based on the familiar
principle of the parallelogram of forces, I gave to the apergic
current a force and direction equivalent to a daily motion of about
750,000 miles in the orbital, and rather more than a million in the
radial line. I need hardly observe that it would not be to the apergic
current alone, but to a combination of that current with the orbital
impulse received at first from the Earth, that my progress and course
would be due. The latter was the stronger influence; the former only
was under my control, but it would suffice to determine, as I might
from time to time desire, the resultant of the combination. The only
obvious risk of failure lay in the chance that, my calculations
failing or being upset, I might reach the desired point too soon or
too late. In either case, I should be dangerously far from Mars,
beyond his orbit or within it, at the time when I should come into a
line with him and the Sun; or, again, putting the same mischance in
another form, behind him or before him when I attained his orbit. But
I trusted to daily observation of his position, and verification of my
"dead reckoning" thereby, to find out any such danger in time to avert
it.
    The displacement of the Earth on the Sun's face proved it to be
necessary that the apergic current should be directed against the
latter in order to govern my course as I desired, and to recover the
ground I had lost in respect to the orbital motion. I hoped for a
moment that this change in the action of the force would settle a
problem we had never been able to determine. Our experiments proved
that apergy acts in a straight line when once collected in and
directed along a conductor, and does not radiate, like other forces,
from a centre in all directions. It is of course this radiation—
diffusing the effect of light, heat, or gravity over the surface of a
sphere, which surface is proportionate to the square of the
radius—that causes these forces to operate with an energy inversely
proportionate, not to the distance, but to its square. We had no
reason to think that apergy, exempt as it is from this law, would be
at all diminished by distance; and this view the rate of acceleration
as I rose from the Earth had confirmed, and my entire experience has
satisfied me that it is correct. None of our experiments, however, had
indicated, or could well indicate, at what rate this force can travel
through space; nor had I yet obtained any light upon this point. From
the very first the current had been continuous, the only interruption
taking place when I was not five hundred miles from the Earth's
surface. Over so small a distance as that, the force would move so
instantaneously that no trace of the interruption would be perceptible
in the motion of the Astronaut. Even now the total interruption of the
action of apergy for a considerable time would not affect the rate at
which I was already moving. It was possible, however, that if the
current had been hitherto wholly intercepted by the Earth, it might
take so long a time in reaching the Sun that the interval between the
movement of the helm and the response of the Astronaut's course
thereto might afford some indication of the time occupied by the
current in traversing the 96-1/2 millions of miles which parted me
from the Sun. My hope, however, was wholly disappointed. I could
neither be sure that the action was instantaneous, nor that it was
otherwise.
    At the close of the third day I had gained, as was indicated by the
instruments, something more than two millions of miles in a direct
line from the Sun; and for the future I might, and did, reckon on a
steady progress of about one and a quarter million miles daily under
the apergic force alone—a gain in a line directly outward from the
Sun of about one million. Henceforward I shall not record my
observations, except where they implied an unexpected or