BEFORE IT HAPPENED.


AT 9 A.M. on Wednesday, September 13, the correspondent of a press
agency dispatched a telegram to London with the intimation that the
great battle at Tel-el-Kebir was practically over. It may possibly
astonish not a few of our readers (says a writer in the _Echo_), to
learn that this message reached the metropolis between 7 and 8 o'clock
on the same morning; and, in fact, had an unbroken telegraphic wire
extended from Kassassin to London, Sir Garnet Wolseley's great victory
might have been known here at 6:52 A.M., or (seemingly) at a time when
the fight was raging and our success far from complete. Nay, had the
telegram been flashed straight to Washington in the United States, it
would have reached there something like 1 h. 44 m. after the local
midnight of September 12. Paradoxical as this sounds the explanation
of it is of the most simple possible character. The rate at which
electricity travels has been very variously estimated. Fizeau asserted
that its velocity in copper wire was 111,780 miles a second; Walker
that it only travels 18,400 miles through that medium during the same
interval; while the experiments made in the United States during the
determination of the longitudes of various stations there still further
reduced the rate of motion to some 16,000 miles a second. Whichever of
these values we adopt, however, we may take it for our present purpose,
that the transmission of a message by the electric telegraph is
practically instantaneous. But be it here noted, there is no such a
thing as a _hora mundi_ or common time for the whole world. What is
familiarly known as longitude is really the difference in time, east
or west, from a line passing through the north and south poles of
the earth; and the middle of the great transit circle is the Royal