Let me give an illustration with the view of explaining more fully
the nature of the relation which the earth bears to the other globes
which abound through space, and you must allow me to draw a little
upon my imagination. I shall suppose that Her Majesty’s mails 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 called among
other intelligent beings elsewhere who can see it. I can only adopt
the title of “Earth,” and therefore I add this line. Now our address
is so complete that from anywhere in the solar system--from Mercury,
from Jupiter, or Neptune--there ought to be no mistake about the letter
finding its way to Mr. John Smith. But from his correspondent in the
Great Bear this address would be still incomplete; they cannot see our
earth from there, and even the sun himself only looks like a small
star--like one, in fact, of thousands of stars elsewhere. However, each
star can be distinguished, and our sun may, for instance, be recognized
from the Great Bear by some designation. We shall add the line “Near
the Sun,” and then I think that from this constellation, or from any
of the other stars around us, the address of Mr. John Smith may be
regarded as complete. But Mr. Smith’s correspondence may be still
wider. He may have an agent living in the cluster of Perseus or on some
other objects still fainter and more distant; then “Near the Sun” is
utterly inadequate as a concluding line to the address, for the sun,
if it can be seen at all from thence, will be only of the significance
of an excessively minute star, no more to be designated by a special
name than are each of the several leaves on the trees of a forest. What
this distant correspondent will be acquainted with is not the earth or
the sun, but only the cluster of stars among which the sun is but a
unit. Again we use our own name to denote the cluster, and we call it
the “Milky Way.” When we add this line, we have made the address of Mr.
John Smith as complete as circumstances will permit. I think a letter
posted to him anywhere ought to reach its destination. To perfect it,
however, we will finish up with one line more--“_The Universe_.”