lanet may have some mountains, and on a globe the
greater part of whose shell is smooth any projections would be
conspicuous, particularly where the sunlight fell at a low angle across
them.

Another form in which the suggestion of interplanetary communication has
been urged is plainly an outgrowth of the invention and surprising
developments of wireless telegraphy. The human mind is so constituted
that whenever it obtains any new glimpse into the arcana of nature it
immediately imagines an indefinite and all but unlimited extension of
its view in that direction. So to many it has not appeared unreasonable
to assume that, since it is possible to transmit electric impulses for
considerable distances over the earth's surface by the simple
propagation of a series of waves, or undulations, without connecting
wires, it may also be possible to send such impulses through the ether
from planet to planet.

The fact that the electric undulations employed in wireless telegraphy
pass between stations connected by the crust of the earth itself, and
immersed in a common atmospheric envelope, is not deemed by the
supporters of the theory in question as a very serious objection, for,
they contend, electric waves are a phenomenon of the ether, which
extends throughout space, and, given sufficient energy, such waves could
cross the gap between world and world.

But nobody has shown how much energy would be needed for such a purpose,
and much less has anybody indicated a way in which the required energy
could be artificially developed, or cunningly filched from the stores of
nature. It is, then, purely an assumption, an interesting figment of
the mind, that certain curious disturbances in the electrical state of
the air and the earth, affecting delicate electric instruments,
possessing a marked periodicity in brief intervals of time, and not yet
otherwise accounted for, are due to the throbbing, in the all-enveloping
ether, of impulses transmitted from instruments controlled by the
_savants_ of Mars, whose insatiable thirst for knowledge, and presumably
burning desire to learn whether there is not within reach some more
fortunate world than their half-dried-up globe, has led them into a
desperate attempt to "call up" the earth on their interplanetary
telephone, with the hope that we are wise and skilful enough to
understand and answer them.

In what language they intend to converse no one has yet undertaken to
tell, but the suggestio