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with tripod and all complete, £25 each. After
they have been some years in service afloat,
they are sent into hospital for overhaul and
repair. This costs generally £4 or £5, and
they are then again as good as ever, and ready
to guide another ship on her way over the
mighty waters. The scientific part of the
fittings of a ship of war, though of greatest
value, are thus of lowest cost. A Standard
Compass is, indeed, a beautiful result of human
ingenuity. Generations of seamen and men
of science have discussed the best form and
materials, and the best mode of suspending
the needle, that it may most freely and truly
follow its mysterious love for the north. From
the days of the old adventurers round the
globe, to the date of the last voyages to the
Arctic regions, successive sea captains have
thought, and watched, and suggested, and the
Standard Compass of the English Navy
combines, it is believed, all that is best in all their
thinking. After the Observatory was established,
and one of its duties had been defined
to be to pursue investigations on the deviation
of the needle, it was thought desirable to have
specimens of the instruments used in the war
ships of other naval nations. With the open
liberality that unites in brotherhood the
scientific men of all countries, France and
Denmark sent specimens of what their best
men had succeeded in perfecting for the use
of their navies. These instruments are very
good, and attract deserved attention in the
observatory-collection of specimens. The
Frenchman is scientific, simple, and with an
excellent contrivance for a moveable agate
plane to avoid friction in the motion of the
needle. The Dane is a good substantial
instrument, even more excellently finished than
the compasses issued to our navy.

The English Compass is, however, believed
with good reason to be the best yet contrived.
It has grown up to its present excellence by
slow degrees. Human ingenuity has been
taxed to its utmost, and it has passed to its
present perfection through the various trials
of needles of all sorts of shapes swung in all
sorts of ways, and by springs, and floating
cards, modifying the instrument to the varying
conditions of a small boat tossing on waves,
or a line of battle ship jarring under the
recoil of a broadside. And now we find our
Compass-needle made of iron that, being got
from the Swedish mines, has travelled to
Strasbourg to be prepared for clock springs;
thence to Paris, to be still more highly
wrought by the watchmaker; and then to
London, to take its sea-going shape. Four
bars of this choice metal, or of shear-steel of
equally fine quality, are ranged edgewise
under a card, thickened and stiffened yet
kept transparent by a sheet of mica, brought
from the Russian mines; this card moves
upon a point made of a metal harder than
steel, and incapable of corrosion; and which
sometimes, under the name of Iridium, but
more correctly under that of "native alloy,"
is found by the refiners as they smelt the
platinum and silver gained from the Ural
Mountains or the mines of Spain. The
Iridium or alloy comes to the workshop
in the tiniest of glass bottlesbottles as
small round as a goose-quill, and about
an inch longin morsels not much bigger
than a pin's head, and weighing each less
than half a grain. Some of these prove
too soft, some too spongy, some too brittle,
but at last one is found hard and good, and
it is soldered upon the pivot, that, when
sharpened and polished, is to work upon a
cap, formed of a ruby, brought from the
East. A bowl of the metal suggested by
the French philosopher being prepared, from
the produce of the mines of Cornwall; and
the science of the English philosopher, and
the skill of the English workman, having
brought all these things into their proper
shape and places; we have, as the result, the
Standard Compass, whose fitness to guide her
Majesty's ship the Unutterable, we have just
seen tested by Captain Johnson at the Woolwich
Compass Observatory.

Our favourite newspaper has just stated
that that gallant ship "is now at Greenhithe
waiting to have her compasses adjusted." So,
then, the instruments so accurate at the
Observatory a few days ago, are all wrong
again on shipboard. Just so. The moment
they get to their places afloat, their fidelity
to the north wavers,—in one ship more,
in another less; but in all in a greater or
smaller degree in proportion to the quantity
of iron used in the construction of the vessel,
and the nearness of that metal to the
compasses; in proportion to the number of the
iron guns and the total weight of metal
carried; to the length of the funnel in steamships,
and to the condition of that funnel
whether upright or hauled down. All this
is both new and strange enough. We have
learnt already what loss of ships convoyed
and ships wrecked has arisen from these
deviations: deviations long neglected on
board all vessels and to this hour
unrecognised or unattended to in our mercantile
marine! Since the Royal Navy, however,
has a scientific officer, Captain Johnson,
especially employed in attending to the
important duty of adjusting the compasses: let
us go with him and his assistant, Mr. Brunton,
from the Compass Observatory to the
anchorage at Greenhithe, and see how he
will "swing" the gallant line of battle ship,
the Unutterable.

The trip occupies a very short time, for we
have steam at command. Arrived in the
Reach, we find five floating buoys anchored in
the stream, one forming a centre, and four
being disposed at equal distances about it,
just as the five pips are placed upon a card
say the five of spades. The good ship to be
operated upon is already fast by the head to
the centre buoy, and Captain Johnson having
mounted her deck, and his assistant, Mr.