THE PLANET-WATCHERS OF
              GREENWICH.

THERE is a morsel of Greenwich Park,
which has, for now nearly two centuries, been
held sacred from intrusion. It is the portion
inclosed by the walls of the Observatory.
Certainly a hundred thousand visitors must
ramble over the surrounding lawns, and look
with curious eye upon the towers and outer
boundaries of that little citadel of science, for
one who finds admission to the interior of the
building. Its brick towers, with flanking
turrets and picturesque roofs, perched on the
side of the gravelly hill, and sheltered round
about by groups of fine old trees, are as well
known as Greenwich Hospital itself. But what
work goes on inside its carefully preserved
boundary and under those moveable,                                                                              black-domed roofs, is a popular mystery. Many                                                                       a holiday-maker's wonder has been excited by
the fall, at one o'clock, of the huge black ball,
high up there, by the weather vane on the
topmost point of the eastern turret. He knows,
or is told if he asks a loitering pensioner, that
the descent of the ball tells the time as truly
as the sun; and that all the ships in the river
watch it to set their chronometers by, before
they sail; and that all the railway clocks, and
all the railway trains over the kingdom are
arranged punctually by its indications. But
how the heavens are watched to secure this
punctual definition of the flight of time, and
what other curious labours are going on inside
the Observatory, is a sealed book. The
public have always been, of necessity,                                                                                 excluded from the Observatory walls, for the
place is devoted to the prosecution of a
science whose operations are inconsistent
with the bustle, the interruptions, the talk,
and the anxieties of popular curiosity and
examination.

But when public information and instruction                                                                           are the objects, the doors are widely
opened, and the press and its attachés find a way
into this, as into many other sacred and                                                                               forbidden spots. Only last week one of ' our own
contributors ' was seen in a carriage on the
Greenwich railway, poring over the paper in
the last Edinburgh Review that describes our
national astronomical establishment, and was
known afterwards to have climbed the                                                                                 Observatory hill, and to have rung and gained
admission at the little black mysterious gate
in the Observatory wall. Let us see what is
told in his report of what he saw within that
sacred portal.

In the park on a fine day all seems life and
gaiety-- once within the Observatory                                                                                boundary, the first feeling is that of isolation.
There is a curious stillness about the place,
and the footsteps of the old pensioner, who
closes the gate upon a visitor, echoes again
on the pavement as he goes away to wake up
from his astronomical or meteorological trance
one of the officers of this sanctum. Soon,
under the guidance of the good genius so                                                                       invoked, the secrets of the place begin to
reveal themselves.

The part of the Observatory so conspicuous
from without is the portion least used within.
When it was designed by Christopher Wren,
the general belief was that such buildings
should be lofty, that the observer might be
raised towards the heavenly bodies whose
motions he was to watch. More modern
science has taught its disciples better; and in
Greenwich,—which is an eminently practical
Observatory,-- the working part of the building
is found crouching behind the loftier towers.
These are now occupied as subsidiary to the
modern practical building. The ground floor
is used as a residence by the chief astronomer;
above is the large hall originally built to
contain huge moveable telescopes and                                                                            quadrants-- such as are not now employed.                                                                      Now-a-days, this hall occasionally becomes a sort of                scientific counting-house— irreverent but                                                                         descriptive term-- in which, from time to time, a
band of scientific clerks are congregated to
post up the books, in which the daily business
of the planets has been jotted down by the
astronomers who watch those marvellous
bodies. Another portion is a kind of museum
of astronomical curiosities. Flamstead and
Halley, and their immediate successors, worked
in these towers, and here still rest some of
the old, rude tools with which their discoveries                                                                   were completed, and their reputation,and                                                                             the reputation of Greenwich, were established.                                                                     As time has gone on, astronomers                                                                            and opticians have invented new and more
perfect and more luxurious instruments.
Greater accuracy is thus obtainable, at a less
expenditure of human patience and labour;
and so the old tools are cast aside. One of them
belonged to Halley, and was put up by him a
hundred and thirty years ago; another is an
old brazen quadrant, with which many                                                                              valuable observations were made in by-gone                                                                   times; and another, an old iron quadrant, still                                                                      fixed in the stone pier to which it was first                                                                              attached. Some of the huge telescopes that
once found place in this old Observatory,
have been sent away. One went to the Cape
of Good Hope, and has been useful there.
Another of the unsatisfactory, and now                                                                                 un-used, instruments had a tube twenty-five
feet long, whose cool and dark interior was
so pleasant to the spiders that, do what they
would, the astronomers could not altogether
banish the persevering insects from it. Spin
they would; and, spite of dusting and cleaning,
and spider-killing, spin they did; and, at length,
the savans got more instruments and less                                                                           patience, and the spiders were left in quiet                                                                         possession. This has been pleasantly spoken                                                                        of as an instance of poetical justice. It is but fair                                                                    that spiders should, at times, have the best of
astronomers, for astronomers rob spiders for
the completion of their choicest instruments.
No fabric of human construction is fine
enough to strain across the eye-piece of an
important telescope, and opticians preserve a