horizon is the circumference of our globe. Beyond the
star-stratum, what? Mere boundless space. Mind says certainly not.
What then? At present we cannot conceive a universe without a
central solar orb for it to gather about and swing around. But that
is only because hitherto our positive, physical knowledge has gone
no farther. It can as yet only travel as far as this, as analogous
beams of light. Light comes from the uttermost bounds of our star
system--to that rim we can extend a positive thought. Beyond, and
around it, whether it is solid, or fluid, or ether, or whether, as
is most probable, there exist things absolutely different to any
that have come under eyesight yet is not known. May there not be
light we cannot see? Gravitation is an unseen light; so too
magnetism; electricity or its effect is sometimes visible, sometimes
not. Besides these there may be more delicate forces not
instrumentally demonstrable. A force, or a wave, or a motion--an
unseen light--may at this moment be flowing in upon us from that
unknown space without and beyond the stellar system. It may contain
messages from thence as this pale visitant does from the sun. It may
outstrip light in speed as light outstrips an arrow. The more
delicate, the more ethereal, then the fuller and more varied the
knowledge it holds. There may be other things beside matter and
motion, or force. All natural things known to us as yet may be
referred to those two conditions: One, Force; Two, Matter. A third,
a fourth, a fifth--no one can say how many conditions--may exist in
the ultra-stellar space, beyond the most distant stars. Such a
condition may even be about us now unsuspected. Something which is
neither force nor matter is difficult to conceive; the mind cannot
give it tangible shape even as a thought. Yet I think it more than
doubtful if the entire universe, visible and invisible, is composed
of these two. To me it seems almost demonstrable by rational
induction that the entire universe must consist of more than two
conditions. The grey dawn every morning warns me not to be certain
that all is known. Analysis by the prism alone has quite doubled the
knowledge that was previously available. In the light itself there
may still exist as much more to be learnt, and then there may be
other forces and other conditions to be first found out and next to
tell their story. As at present known the whole system is so easy
and simple, one body revolving round another,