ountry extend not
only over this globe, but that they also communicate with other
worlds; that postal arrangements exist between Mars and the earth,
between the sun and Orion--in fact, everywhere throughout the whole
extent of the universe. We shall consider how our letters are to be
addressed. Let us take the case of Mr. John Smith, merchant, who lives
at 1001, Piccadilly; and let us suppose that Mr. John Smith's business
transactions are of such an extensive nature that they reach not only
all over this globe, but away throughout space. I shall suppose that
the firm has a correspondent residing--let us say in the constellation
of the Great Bear; and when this man of business wants to write to Mr.
Smith from these remote regions, what address must he put upon the
letter, so that the Postmaster-General of the universe shall make no
mistake about its delivery? He will write as follows:--

MR. JOHN SMITH,
1001 Piccadilly,
London,
England,
Europe,
Earth,
Near the Sun,
Milky Way,
The Universe.

Let us now see what the several lines of this address mean. Of course
we put down the name of Mr. John Smith in the first line, and then we
will add "1001 Piccadilly" for the second; but as the people in the
Great Bear are not likely to know where Piccadilly is, we shall add
"London" underneath. As even London itself cannot be well known
everywhere, it is better to write "England." This would surely find
Mr. John Smith from any post-office on this globe. From other globes,
however, the supreme importance of England may not be so immediately
recognized, and therefore it is as well to add another line, "Europe."
This ought to be sufficient, I think, for any post-office in the solar
system. Europe is big enough to be visible from Mars or Venus, and
should be known to the post-office people there, just as we know and
have names for the continents on Mars. But further away there might be
a little difficulty; from Uranus and Neptune the different regions on
our earth can never have been distinguished, and therefore we must add
another line to indicate the particular globe of the solar system
which contains Europe. Mark Twain tells us that there was always one
thing in astronomy which specially puzzled him, and that was to know
how we found out the names of the stars. We are, of course, in
hopeless ignorance of the name by which this earth is ca