he is detailed, as a vacancy occurs, for actual service.

Having thus discovered how our friend the sergeant came into his
post, we looked about to see what he had to do there. The
brilliantly-colored flags overhead drew the eye first. These flags
serve the purpose of an international language on the high seas, where
no other language is practicable. Twenty thousand distinct messages
can be sent by them. Rogers's system has been, adopted by the United
States Navy, the Lighthouse Board, the United States Coast Survey and
the principal lines of steamers. Each flag represents a number, and
four flags can be hoisted at once on the staff. With the flags there
is given a book containing the meaning of each number. Thus, a wrecked
ship cries silently to the shore, "Send a lifeboat" by flags 3, 8, 9,
or says that she is sinking by 6, 3, 2; or a vessel under full sail
hails another by 8, 6, 0, or bids her "_bon voyage_" with 8, 9, 7.
Owing to the difficulty of distinguishing colors in cloudy days or
when the flags will not fly, other systems of signaling are used: that
of cones similar to umbrellas being considered in the English service
one of the most efficient, a different arrangement of cones on the
staff representing the nine numerals. Men may convert themselves into
cones in an emergency by raising or letting fall their arms, and two
men thus give any signal necessary. As the flags, however, belong
more especially to Sergeant G---- 's duty on the field of battle or to
exceptional cases of storm and danger, we pass them by to examine into
his daily round of duty. Outside, a queer little house of lattice-work
perched on a headland shelters the thermometers and barometers: on
a still higher point directly over the foaming breakers is the
anemometer, the little instrument which measures the swiftness of the
fiercest cyclone as easily as the lightest spring breeze. It consists
of four brass cups shaped to catch the wind, and attached to the ends
of two horizontal iron rods, which cross each other and are supported
in the middle by a long pole on which they turn freely. The cups
revolve with just one-third of the wind's velocity, and make five
hundred revolutions whilst a mile of wind passes over them. A register
of these revolutions is made by machinery similar to a gas-meter.
The popular idea, by the way, of the speed of the wind runs very far
beyond the truth: we are apt to say of a racer that he goes like the
wind, when the