188 DR. FARADAY’S EXPERIMENTAL RESEARCHES IN ELECTRICITY. (SERIES XXIII.) 
Plan of the Apparatus employed in Dr. Faraday’s Researches, Series XXIII. p. 172. 
a, h, c frame board ; d, d, d wooden lever, of which e is the axis, / the crank-wheel, and g the 
great wheel with its handle A; i the bar connecting the crank- wheel and lever; k a cylinder or core 
of metal to be submitted to experiment ; I the rod connecting it with the lever ; m the helix of the 
electro-magnet ; n the iron core, and o the exciting battery ; p the experimental helix ; q the galvano- 
meter, 20 feet from the electro-magnet ; ?■ the commutator ; w, vj connecting wires ; s, s springs of 
brass or copper ; t a copper rod connecting the two arms of the lever, to give strength. The plan is 
to a scale of one-fifteenth : the part at the electro-magnet and experimental helix is in section ; the 
further description is in paragraphs 2643, 2644, 2645 and 2648 of the Experimental Researches. 
