186 



FRESNEL. 



FLASHING I.IGIIT BY REFLECTOI 



left. The cord D, descending from the pulley, passes over 

 another pulley not seen, and has a weight like a clock- 

 weight attached to it. The clock-work by which the de- 

 scent of the weight is regulated and the force communica- 

 ted to the system of reflectors is inclosed in the box E. 

 The little truck wheels on which the system revolves are 

 seen beneath, on the platform formed upon the top of the 

 stand, where they roll in a groove formed for the purpose. 

 The machinery is arranged so that the lamps revolve 



