."). Photographs of electric discharges in a strong electro- 

 magnetic field show distinctly spiral structure. 



In Fig. 11, Let a stream of dextrons or negative charges 

 I).- flowing from B to A in the conductor BA. Let F and B 

 be the cross-sections of the upper and lower part of the spiral 

 line of fore- EF, which is swelling out around the currenl BA 

 due to an increase in its rate of flow. The cross at E indi- 

 cates that the spiral is moving into the paper away from the 

 observer, and the point at F indicates that the spiral at that 

 point is coming up out of the paper toward the observer. The 

 half of the spiral ring toward the observer is entirely cut away. 

 The arrows at and 0' indicate the direction of motion of 

 the line that constitutes the spiral. The line of force is thus 

 seen to he a spiral ring swelling out around the current. 



Figure 11. 



As this ring swells out and approaches the neighboring 

 conductor CD, the outer part of the spiral at X is moving 

 toward the right as indicated by the arrow at X. Therefore 

 when this plunges into CD. it tears loose a dextron and shoots 



i1 m the direction of CD. i. e. in the direction in which it is 

 moving. As it does so the motion of the line FF is absorbed 

 either wholly op in part. If only in part it tears loose other 

 dextrous and it tears them loose until its motion is all absorbed, 

 its motion being converted into linear motion of the dextrous 

 torn loose. As this process takes place, the upper part of l he 

 spiral at <> does not reach the line i'\). because the the spiral 

 delivers all of its motion to dextrons along the arrow at X. 

 before it can do so. 



If the currenl in |',A be falling in its rate of flow instead 

 of rising, the line FF falls in upon Ali. and if CD is between 

 FN and AD. the point <> of the spiral strikes CD first, with 



