WAVES.


In the first days of August, two startling announcements reached us
from the United States. They were as follows:

(1.) "The commander of the Cunarder Umbria reports that at 3 o'clock
on July 27, about 1,500 miles from Sandy Hook, the vessel was struck
by a tidal wave 50 ft. high, which swept the decks, carried away a
portion of the bridge and the forward hatch, and flooded the cabins
and steerage."

(2.) "The captain of the Wilson line steamer Martello reports that at
half-past 8 on the evening of July 25, when in lat. 49° 3' N., long.
31° W., an enormous wave struck the vessel, completely submerging the
decks."

In view of these reports, and inasmuch as questions were asked on the
subject in Parliament, though it is quite possible that, as regards
the "tidal" character of the waves, there may be something of
newspaper _gobemoucherie_ in the announcements, we offer a few remarks
on _waves_ in general, which may be useful to some of our readers.

_Tidal phenomena_ present themselves under two aspects: as alternate
elevations and depressions of the sea and as recurrent inflows and
outflows of streams. Careful writers, however, use the word _tide_ in