.
Another of the unsatisfactory, and now unused 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 eyepiece of an
important telescope, and opticians preserve a particular race of
spiders, that their webs may be taken for that purpose. The spider lines
are strained across the best instruments at Greenwich and elsewhere; and
when the spinners of these beautifully fine threads disturbed the
accuracy of the tube in the western wing of the old Observatory, it was
said to be but fair retaliation for the robberies the industrious
insects had endured.

A narrow stair leads from the unused rooms of the old Observatory to its
leaded roof, whence a magnificent view is obtained; the park, the
hospital, the town of Greenwich, and the windings of the Thames, and,
gazing further, London itself comes grandly into the prospect. The most
inveterate astronomer could scarcely fail to turn for a moment from the
wonders of the heavens to admire these glories of the earth. From the
leads, two turrets are reached, where the first constantly active
operations in this portion of the building, are in progress.

At the present time, indeed, these turrets are the most useful portions
of the old building. In one is placed the well-known contrivance for
registering, hour after hour, and day after day, the force and direction
of the wind. To keep such a watch by human vigilance, and to make such a
register by human labor, would be a tedious, expensive, and irksome
task; and human ingenuity taxed itself to make a machine for perfecting
such work. The wind turns a weather-cock, and, by aid of cog-wheels the
motion is transferred to a lead pencil fixed over a sheet of paper, and
thus the wind is made to write down the direction which itself is
blowing. Not far distant is a piece of metal, the flat side of which