distance of a second of a degree from each other, just as one sees the
surface of large maps traced by meridians, nearly thirty of those lines
would then have been covered in by the east and west span of the crystal
roof. Mr Dent's clock might have been set to the precise time of the
Greek Slave, and it would yet have been nearly two seconds wrong by the
time of the Liverpool Model. The pendulum swinging so steadily within
its case had a longer and more stately stride than most of its
congeners. It took a second and a half of time to complete its step from
side to side. But notwithstanding this, if a string had been suddenly
stretched across in space above the east end of the building, and left
there in free suspension, independent of all connection with the
terrestrial surface, it would have taken longer for the huge structure
to be trailed beneath it by the earth's rotation--swift as that rotation
is--than it did for the sober and leisurely mass of metal to finish its
beat from side to side.

Our immediate business, however, at this present time is not with the
geographical relations of Mr Paxton's building, but rather with that
sober and leisurely-moving mass--the pendulum. Even in the seventeenth
century, old Graunt was shocked when some irreverent babbler spoke of
one of its honourable race by the rude epithet of 'a swing-swang;' and
he penned an indignant protest on the subject to the Royal Society.
Since that time the pendulum has done much more to merit the reverence
of the world. Plain and simple as its outward bearing is, it really
holds a high and dignified position in the annals of science.

Instead, however, of touching upon its pedigree and achievements, we
proceed at once to speak of certain interesting peculiarities that enter
as an element into all considerations in which it has concern. In the
first place, what is that characteristic motion which it so constantly