We will start outwards from the Sun, and glance on our way at the
worlds involved in the Solar System. Let us first understand what are
the dimensions of our central Luminary. The distance of the Moon from
the Earth is 240,000 miles, but the dimensions of the Sun are so great
that, were the centre of the Sun placed where the centre of the Earth
is, the surface of the Sun would not only extend as far as the Moon,
but as far again on the other side, and that would give the radius
only of the enormous circumference of the Sun; another way to
understand its size is, to remember that, light travelling 186,000
miles per second, would actually take five seconds to go across its
disc. Let us now start outward from this vast mass. The first world we
meet is the little planet Mercury, only 3000 miles in diameter,
revolving round the Sun at a distance of 36 million miles. We next
come upon Venus, at a distance of 67 million miles. She is only 400
miles smaller in diameter than our Earth, and, with the dense
atmosphere with which she is surrounded, animal and vegetable life
similar to that on our Earth would be possible. Continuing our course,
we arrive at our Earth, situated 93 million miles away from the Sun.
Still speeding on, a further 50 million miles brings us to Mars, with
a diameter of nearly 5000 miles, and accompanied by two miniature
moons. The sight of this planet in a good instrument is most
interesting. Ocean beds and continents are visible, and the telescope
shows large tracts of snow, though not necessarily formed from water
(perhaps carbonic dioxide), surrounding its polar regions, which
increase considerably during the winter, and decrease during the
summer seasons on that planet; but there are no canals! The fact that
our largest and best telescopes failed to show these imaginary canals,
was an insurmountable barrier to the advocates of these markings, but
the "Canalites" made their contention ridiculous when they actually
suggested that the reason for this failure to perceive them was that
our telescopes were too large to see such small markings! How such a
statement could have been made is incomprehensible on any supposition,
as everybody knows that the whole use of size, or what is called
aperture, in a telescope, is to help us to see more clearly small and
faint markings.

The distances we now have to travel become so great that I shall not
attempt to give them; you can, however, form an idea of the tremend