_G_. (_Checking an impulse to smile and shaking his head_), "Oh, no!
Never."

_I_. "Yet science is working miracles, or what would have been
accounted miracles in ancient times."

_G_. "No doubt, and hence people are apt to suppose that science can do
everything; but after all Nature has set bounds to her achievements."

_I_. "Still, we don't know what we can and what we cannot do until we
try."

_G_. "Not always; but in this case I think we know. The celestial bodies
are evidently isolated in space, and the tenants of one cannot pass to
another. We are confined to our own planet."

_I_. "A similar objection might have been urged against the plan of
Columbus."

_G_. "That was different. Columbus only sailed through unknown seas to a
distant continent. We are free to explore every nook and cranny of the
earth, but how shall we cross the immense void which parts us from
another world, except on the wings of the imagination?"

_I_. "Great discoveries and inventions are born of dreams. There are
minds which can foresee what lies before us, and the march of science
brings it within our reach. All or nearly all our great scientific
victories have been foretold, and they have generally been achieved by
more than one person when the time came. The telescope was a dream for
ages, so was the telephone, steam and electric locomotion, aerial