242 



Wisconsin Academy of Sciences, Arts, and Letters. 



Fig. 3. 



quartz employed, some being right-handed and some left-handed. 

 Certain substances such as quinine, turpentine, tartaric acid, cane 



Fig. 2, shows the direction of the motion at each point around and close to 



the core, or circular axis of a vortex ring. 

 Fig. 3, shows the relation between the di- 

 rection of motion of the entire ring and 

 the direction of 

 rotation around 

 the core. It is 

 seen to be in a 

 direction "per- 

 pendicular t o 

 the plane of the 

 ring, towards 

 the side towards 

 which the ro- 

 tatory motion carries the inner parts of the ring." The direction of the motion 

 of the fluid in which the vortex ring exists, at different distances from the 

 axis of the ring, both within the ring and without it, corresponds to the direc- 

 tion of the lines of magnetic 

 force around a circular con 

 ductor in which an electrical 

 current is maintained, (like 

 the ring of a tangent galvan- 

 ometer, for example,) and the 

 velocities of the fluid in va- 

 rious parts, will be in propor- 

 tion to the intensities of the 

 magnetic forces around this 

 circular conductor, in va- 

 rious parts of the magnetic 

 field, which is due to the elec- 

 tric current passing through 

 the conductor. 



The directions of these 

 lines of magnetic force, sur- 

 rounding a circular conduct, 

 or are shown in Fig. 4, taken 

 from Prof. Clerk Maxwell's 



admirable treatise upon Elec- j^g^ 4 



tricity and Magnetism. The small circle represents i section of the circular 

 conductor conveying the electric current, while the oval lines represent the 

 lines of magnetic force surrounding it. Were the conductor merely a 

 straight wire, the lines of magnetic force would be circles surrounding it. 



