216 The East Anglian Earthquake.
and B are cemented down to the timber balk, T T, which is
about one foot square, and passes at each end into the wall
of the Observatory, where it is firmly bricked in. The pier, C,
rests upon, but is not fixed to, a similar balk, T' T', which runs
as shown in the plan. Through the kindness of Mr. Prince
we are enabled to give a figure of the instrument (fig. 18).
The three piers, A, B, and C, pass through holes cut
through the boarding of the floor, of such a size as to allow
the piers to be free from contact with the floor at any point.
The height from the surface of the ground to the top of the
stone slabs, A, B, is 34 feet, and the height of the piers above
Ordnance datum is 822 feet, the Observatory being situated
Fig. 17.—Plan of Crowborough Observatory.
on a hill 788 feet above Ordnance datum. The triangular
base of the telescope rests on the piers upon three points; at
A there is a conical metallic "leg" on the under side, and
forming part of the base, this cone resting with its apex
downwards in a depression in the stone slab; at B and C the
base is supported by levelling-screws. At 0 the triangular
base is provided with screws capable of moving the instrument
in azimuth.
For twelve years this telescope had stood in this position
without getting out of adjustment, and had occasionally been
used after the earthquake for ordinary observations, without