224 Royal Society : — Mr. A. E. Donkin on an Instrument 



a rectangular frame, E F Gr H, capable of sliding horizontally up and 

 down in a direction parallel to that of the plane passing through the 



spindles. This frame has a pair of rollers, E F and Gr H, at each end 

 connected by tape bands, between which the paper passes as the rol- 

 lers turn. In order to give a motion of revolution to the rollers, a 

 wheel, L, is fixed upon the axis of one of them whose teeth gear 



