420
Class 10.—PHILOSOPHICAL, MUSICAL, IIOBOLOGICAL,North, North Central, and South Central Galleries.
rUNiTKi’
while the teeth of the other part are used for thepurpose of locking the train, in order to prevent itrunning forward from the action of the wind on theextra-sized hands which present a large surface. Acentral vertical wheel, h, of larger diameter (see fig. 2and fig. 3), which works into a pinion, c, on the arbor ofthe escape wheel, gives motion to the wheel-work in
connexion with the hands, which are at a height of 40 feeabove the pedestal in the South Gallery of the Transepton which the machinery is placed, the communicationbeing effected by a 12-inch bevelled wheel, d, which rotateson the end of *the spindle of the great wheel, and worksinto a horizontal bevelled wheel, e, with which a verticashaft, /, made of brass tubes of lj inch diameter, an
Fig. 3.
~WTig
mfM
fc'11,.,1//, 1 /]
screwed together in several lengths, revolves, and which,in connexion with wheel-work at top, gives motion to thehands.
In order that the clock-face might harmonize withthe design of the south elevation of the Transept, itwas considered that the conventional form of a circlefor the dial might be dispensed with; the figures wereaccordingly arranged in a semicircle, and placed at theintersections of the radial bars with the second semi-ring from the centre of the great fanlight.—(See fig. 4.)As is the case in ordinary dials, so in the present in-stance, XII. is at the top, I. to VI. following on the right-
hand side of the semicircle; while on the left si<I efigure VI. is repeated, and the remaining figures U PXI. inclusive follow in the usual order. In order to renthe new form of dial perfectly useful, it was necessarj ^have two minute hands, and also two hour hands;that when one of the minute hands, for instance, *® a jthe figure VI. on the right hand, the other minute t 1 ^also points to the corresponding VI. on the leftThe two minute hands together are 16 feet, and thehour hands 12 feet in length respectively. Twodials, each of five feet diameter, are fixed up inside
Shepherd's Patent Electro-Magnetic Clock