370 



RECENT PROGRESS IN PHYsICS. 



n, on the inner sides of which there are mortises for the reception of 

 the rubber ; along the middle of the face of w there runs a strip of tin 

 foil which receives the electricity from the spring of the rubber, and 

 leads it to the negative conductor o. 



The rubber itself is shown in fig. 8, the oiled silk attached to it 

 being omitted. ^ is a wooden slide which goes into the mortise of the 

 support n. q is a projection which prevents the rubber from slipping 

 out. Upon the slide p the amalgamated leather r is fastened. When 

 the rubber is slid into its place, the metallic spring s, screwed by its 

 narrow end to p, is compressed, and thus forces the rubber against 

 the glass plate. 

 Fiff. 6. 



Fiff. 8. 



In the middle of the projection q, a strip of tin foil is seen ; this 

 leads from the amalgamated side of the leather to the spring s, from 

 which the electricity is conveyed to the conductors o in the_ manner 

 above described. 



