*1 



LOCAL MAGNETIC STOBMS.* 

 Fbancis E. Niphek. 



The work of the Ampere nearly a century ago, taken 

 in connection with the fact that fragments of a steel 

 magnet are also magnets, was sufficient grounds for the 

 theory that the molecules of magnetic matter may con- 

 tain closed electric currents. The discovery of the elec- 

 tron gave additional weight to the older suggestion. 

 With a view of obtaining direct evidence of this condi- 

 tion within a steel magnet, the writer began a series of 

 experiments which have led to interesting results, but 

 which leave the original question unanswered. 



It appeared possible that the magnetic force of a steel 

 magnet might be varied by draining negative electrons 

 from it. This was done by connecting it with the positive 

 terminal of an influence machine. 



The magnet to be tested was 30 cm. in length and about 

 2.5 cm. in diameter. It was composed of a thin film of 

 steel 0.2 mm. in thickness. It was formed of a single 

 layer of steel wire wound longitudinally on a piece of 

 rubber hose, rendered rigid by means of a core of wood. 

 The winding was in the form given the copper windings 

 of a drum armature. The wire was held in place by silk 

 cord, and the steel wire crossing the ends of the hose 

 was removed. The wire was then magnetized. 



This wire magnet was used as a deflecting magnet, 

 being placed at right angles to a needle suspended on a 

 silk fiber. The needle was wholly enclosed in a metal 

 shield. A mirror attached to the suspension was ob- 

 served through a glass window covered with copper wire 

 gauze. A telescope and scale was used in observing de- 

 flections, one mm. having an angular value of 3'.4. The 

 deflecting effect of the wire magnet was balanced by a 



♦Presented March 3, 1913. 



(59) 



