629 



My first crude graphite battery of twelve pairs of plates was set 

 up on April 5th, 1849, for working the telegraph from my residence 

 at Tonbridge to the Telegraph Office about a mile distant. It was 

 charged with sand saturated with diluted acid ; and had not been dis- 

 mounted in March 1851, when I changed my abode. During the 

 interval, the sand was from time to time moistened with acid water or 

 water only. The plates in this case had been roughly chipped out and 

 rubbed on stone into something like shape. In the mean time I 

 had some sets of plates cut at the Locomotive "Works, Ashford, and 

 was thus enabled to obtain further results. I forwarded a graphite 

 battery to the Great Exhibition in 1851, for which a prize medal 

 was awarded. The introduction of graphite into anything like 

 general use was for a long period no easy matter, on account of the 

 difficulty of finding any one who would undertake to cut it into 

 plates, its hardness destroying the tools ; and the then limited de- 

 mand did not encourage any one to construct special machinery for 

 the purpose. My wants at length reached the ear of Mr. J. Robin- 

 son of Everton, Liverpool, who took the matter thoroughly in hand, 

 and has succeeded perfectly in cutting plates into any form and to 

 comparatively any size, at a very moderate cost, for which I am much 

 indebted to him. I have before me plates 12 inches X 10 inches, 

 of smooth texture and uniform thickness, and have seen some of 

 double that size. 



The plates in common use for bell signals are 7\ inches x 3 inches 

 and |- inch thick, of which about 2000 are in daily use on the South 

 Eastern Railway, and the greater portion of these are now platinized. 

 The plates are delivered to me in their crude state, that is to say, 

 they are merely cut into form. Immediately on arrival they are 

 placed in a stone pan, and covered with a mixture of 1 sulphuric 

 acid + 4 water, in which they are allowed to remain for three or 

 four days or more. They are taken out as required, and are washed 

 under a tap of running water ; this operation dissolves out any foreign 

 matter that might be pernicious in a voltaic combination wherein 

 sulphuric acid was employed ; they are then partially dried. A hole 

 for a rivet is next drilled in the middle, near the top of each plate 

 a belt of varnish one inch wide is applied to the top on both sides of 

 each plate a blank one inch square, having the rivet hole for its 

 centre, being left unvarnished on each side electrotype copper is 



2 u 2 



