ELECTRO-MAGNETIC INSTRUMENTS. 33 



Fig. 453. 



will, in general, apply to this ; the mahogany base is twelve 

 inches long and five inches wide, the electro-magnets sup- 

 ported at a distance of nine inches from each other, over 

 which a walking beam, with curved armatures attached to 

 the ends, is made to vibrate, giving motion to a bent lever, 

 the spindle of which is supported by two brass pillars, 

 which again gives motion to a spindle having a crank, on 

 which the fly-wheel is fixed ; the springs and break-piece 

 being arranged as in the preceding instrument. 



Price, $18.00. 



Magnetic Engine. (Fig. 454, next page.) In this ar- 

 rangement the electro-magnets are supported on a round 

 mahogany base, to which they are firmly clamped ; four 

 brass pillars support a circular brass plate through which 

 the poles of the magnets pass, and over which two arma- 

 tures connected together vibrate. Two pillars are screwed 

 to the plate, over the projecting ends of two of the lower 

 pillars which support the spindle, having the crank and fly- 

 wheel, and to which the break piece is attached ; there is a 

 short pillar at the side of the plate supporting a bent lever, 

 giving motion to the crank by the alternate action of the 

 armatures ; the silver springs pass from the base and press 

 against the breakpieces alternately, as described in Fig. 452, 



