The telegraph manual: a complete history and description of the semaphoric, electric and magnetic telegraphs of Europe, Asia, Africa, and America, ancient and modern.

188 HISTORY OF THE ENGLISH TELEGRAPH.
rapidity of a succession of signals, greater accuracy of mechanism would be required. If the signals could be given by divisions of the mechanical motion similar to the divisions made by
the escapement of a clock, the necessity of accurate timing
would be altogether avoided, for it would then be only necessary that every intervention of the attractive force of the magnet, should occasion or allow a motion of the armature or
Fig. 11. pallet of each escapement,
without its being necessary. (\,that a motion of the pallet....>I I ~,0 i should occupy, in each in> strument, precisely the same
of" A z \ period of time.
Fig. 11 is an extension of
the telegraph, based upon
1! the plan of the musical
lo6 t' snuff-box. The engraving
^(1111111 I is an outline view of the
mechanism. The parts in
fig. 11 are indicated by dif_ v____ ferent letters from those used
in figs. 9 and 10. In the for15m ~ mer A A are the cylinders
or barrels containing the
I f; \ / keys; M is the alarum bell;
tt ss|*,/ go T L the magnets; B,, D,
a A, ^',1 and E, are the ends of vari\.'[L- ~ 1. ( \ \ |ous cylinders.,Yi u', - A; I do not deem it necesd<-^ ^ J l sary to give a detailed de-:> ]<5< 1js scription of the mechanical arrangement of the
apparatus, believing that
4 f).'8 s~sufficient has been shown
I^'^~~'t to enable the reader to un-- ^'';.cderstand the general plan.
7, %y\ ] It is the first mechanical
) 9' telegraph invented by Mr.
\,'0,/ (Cooke, in March, 1836.
THE ESCAPEMENT APPARATUS.
In July, 1836, Mr. Cooke produced his experimental escapement instrument, represented by figures 12 and 13, based
upon the principle of the vibrating pendulum, alternately retained by one of two magnets, on the same conducting wire,