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 suggestion has sapiently been made that, mathematical
facts being invariable, the eternal equality of two plus two with four
might serve as a basis of understanding, and that a statement of that
truth sent by electric taps across the ocean of ether would be a
convincing assurance that the inhabitants of the planet from which the
message came at least enjoyed the advantages of a common-school
education.

But, while speculation upon this subject rests on unverified, and at
present unverifiable, assumptions, of course everybody would rejoice if
such a thing were possible, for consider what zest and charm would be
added to human life if messages, even of the simplest description, could
be sent to and received from intelligent beings inhabiting other
planets! It is because of this hold that it possesses upon the
imagination, and the pleasing pictures that it conjures up, that the
idea of interplanetary communication, once broached, has become so
popular a topic, even though everybody sees that it should not be taken
too seriously.

The subject of the atmosphere of Mars can not be dismissed without
further consideration than we have yet given it, because those who think