and Phenomena of Magnetic Induction. 281 



Series C. 



With two equal bar-magnets, placed over each other at a few 

 inches distance, with opposite poles contiguous. 



As in all the experiments of the first series, the magnetism in- 

 duced on the different masses of iron was chiefly upon the por- 

 tions nearest to the magnets, the influence on the opposite ex- 

 tremity of each portion being merely consequential, it occurred 

 to mcj that if the substances employed in the experiments were 

 placed betwixt the two opposite poles of a pair of magnets, so 

 that the appropriate polarity might simultaneously be developed 

 at both extremities of the iron, a much more powerful action 

 might be expected. In this expectation I was not disappointed ; 

 for, adopting the arrangement represented in PL IV. Fig. 13, 1 

 found that experiment No. 4. could now be accomplished at dis- 

 tances considerably greater, and experiment No. 2. with a great- 

 er number of balls, whilst a variety of new illustrations of the 

 phenomena of magnetic induction were successively suggested, 

 as I proceeded with the amusing investigation. 



Experiment 1. — For the vertical support of Nails and Wires 

 on their points. 



Iron^wires («, 6, PI. IV. Fig. 14.), placed vertically on their 

 pointed extremity, can be supported by the large magnets at 

 the distance of two inches from the upper magnet, and the nail 

 c, weighing 326 grains, at the distance of an inch and a half 

 from it. 



Experiment 2. — Small Figures in paper, or card hoard, ver-,-. 

 tically supported. 



A pleasing variety is produced in the foregoing e^^periment, 

 by attaching the iron-wires to little figures cut out of paper 

 (PI. IV. Fig. 15.), which, standing upright betwixt the magnets, 

 and quivering on the points of the wire, are made to vibrate, or 

 whirl round, in mimic life, by approaching them with another 

 magnet, and waving it around them. These figures, three 

 inches in height, can be readily sustained at the distance of an 

 inch from the upper magnet, the magnets themselves being four 

 Inches apart. 



