^14 Mr. C. Tomlinson's Experiments on the Electrical Fly, 



the simultaneous action of the two opposing forces, and meeting 

 in the centre broke into a whirlpool of a sufficiently definite 

 character to produce rotations (see fig. 5). A cork thrown on 

 the surface was whirled round in circular and elliptical lines 

 from wire to wire, showing clearly that the action was one of 

 attraction and repulsion. The direction of the curve was from 

 right to left; but I found that on shifting the places of the 

 wires with respect to each other, the direction of the curve could 

 be varied from right to left or from left to right at pleasure. 

 Here, then, was an explanation of the contradictory effects 

 obtained with the fly in liquid dielectrics. The fly had no more 

 to do with the generation of the current than the cork had ; it 

 was merely swept round in the current, in whatever direction 

 that might be, according to the line of least resistance connect- 

 ing the two wires. A hole was now drilled through this shallow 

 dish for the reception of a needle-point on which the fly was 

 mounted, when it was found perfectly easy to make the fly rotate in 

 either direction by a slight adjustment of the conducting wires. 



In this experiment with the cork playing between two wires 

 on the surface of the liquid dielectric, we have only a horizontal 

 adaptation of Volta's experiment with the pith-balls between oppo- 

 sitely electrified surfaces, or the dancing figures between two 

 electrified copper discs, or Franklin's electrical pendulum. 



In this form of the experiment a number of beautiful electrical 

 effects were obtained which do not belong to my present sub- 

 ject ; but there are one or two that may be mentioned as throw- 

 ing light upon the action of points on a dielectric medium. A 

 number of particles of gold- and silver-leaf were put into tur- 

 pentine contained in the shallow dish, and on working the 

 machine they simply arranged themselves between the two 

 wires as a conducting link*; but on removing the earth-wire 

 and holding a point over the liquid, induction took place, the 

 particles became polarized, the metallic particles started asun- 

 der, and a current set in in the most beautiful and orderly 

 manner, the metallic particles flowing in several parallel lines 

 towards the prime conductor wire, striking upon it, and imme- 

 diately being repelled, they passed away on either side of it 

 round the edge of the liquid in symmetrical curves up to the 

 negative point held over the vessel, and then set in as before 

 toward the positive wire (see fig. 6). When the latter was 

 raised a little way out of the liquid, and the negative point in- 

 serted into it, a rapid series of discharges took place among the 

 particles, lighting up the vessel, and producing a beautiful effect 

 in the dark. 



* Faraday obtained a similar result with particles of silk between two 

 conducting wires in turpentine. See Experimental Researches, § 1350. 



