294 Mr Bryson on a Kew Method of 



of considerable expense in fitting up the self-acting machinery 

 for lighting and extinguishing the gas, and, second, to the in- 

 distinctness of the figures at night. To obviate these, I pro- 

 pose the following plan, which appears to offer several advan- 



tages. 



Fig. 1. 



The method now in use is illustrated by fig. 1. The wheels 

 marked 42 and 48 are the usual motion-wheels used in every 

 clock for the purpose of connecting the hands. An additional 

 pinion of twelve is put on the wheel of 42 to turn the wheel 

 96. This wheel has thirteen pins, one hour's motion apart, 

 which raise the lever /, and allow it to fall when the pins have 

 passed. During the time the lever is up (as shewn by the 

 dotted lines), its opposite end m, by means of the connecting 

 rod w, keeps the lever o of the gas-cock p down, and thus 

 nearly closes it, allowing the passage of just enough of gas to 

 keep the burners at a blue flame. 



When the weight I drops, the handle o is raised, and opens 

 the stop-cock p to its full extent, and the dial is thus illumi- 

 nated. 



Fig. 2 is the method proposed as simpler, and acting with 

 much less friction on the clock. r r are the two motion- 

 wheels ; h is the hour- wheel of 48 teeth, driving the large 

 wheel WW of 96, round the circumference of which are 

 placed a series of holes, screwed to fit two pins with milled 

 heads, one of which is represented at D. II are two le- 

 vers, both attached to the stop-cock C ; L L are portions 

 of the two leading pipes which communicate with the burners. 

 pppp are the 4 pillars on which the plate is supported for 

 the pivots of the motion-wheels r r working in. A B is a 

 strong wooden frame to which all the apparatus is attached. 



