14 BENJ. PIKE'S, JR. DESCRIPTIVE CATALOGUE. 



Fig. 426. 



The Magic Circle. (Fig. 426.) This consists of a coil 

 of coarse insulated copper wire, through which is placed 

 two semicircular pieces of soft iron, the faces accurately 

 fitted to each other, and when together forming a ring ; to 

 each portion there is attached a handle for holding by. On 

 connecting the ends of the coil with the poles of a galvanic 

 battery, the ring being placed within the coil, the two parts 

 are held firmly together, although there may be no contact 

 between the coil and the ring, and requiring considerable 

 force to separate those of the best make with ball and 

 socket handles, resisting the power of two men to separate. 

 Price, with ring handles, $1.00, $1.50, $1.75. 



$2.50. 

 " with ball and socket handles, $7.00. 



Iron Rod supported in the Air within a Wire Helix. 

 (Fig. 427, next page.) This apparatus consists of a helix, 

 or coil of coarse insulated copper wire, of about two or 

 three inches in length, and about the same diameter, hav- 

 ing, an aperture in the centre of the coil of about one-third 

 or one-half of an inch in diameter, the terminations of the 

 wire being arranged for connecting with the cups of a gal- 

 vanic battery. A rod of soft iron of about three times the 

 length, and somewhat smaller than the interior of the helix, 

 to allow it to pass through with perfect freedom, is placed 

 within it. If now the connexions are made with a power- 

 ful battery, the rod will be supported within the coil, resist- 

 ing considerable effort to displace it, and when forced out 

 of its position bounding back to its former place. 



