1861.] 231 



their former position, and thus a temporary suspension of the vibra- 

 tions (20) was obtained, no shocks were experienced at the secondary 

 terminals until the vibrations spontaneously recommenced they 

 were then felt distinctly ; nor were any shocks felt whilst a platinum 

 cathode of equal surface (one square inch) to the one of mercury 

 was employed as a substitute for the ring, although an equal quantity 

 of electricity appeared to be circulating ; nor were any shocks expe- 

 rienced with two Smee's elements whilst the pool of mercury formed 

 the cathode, because no vibrations of the mercury then occurred ; 

 but on increasing the number of elements to four (immersed the same 

 depths) vibrations commenced, and induction currents occurred and 

 continued, not only whilst the phonetic crispations existed, but also 

 whilst only the circular furrows (32), which emit no perceptible sound, 

 were visible. The absence of induced currents with a battery nearly 

 but not quite strong enough to produce vibrations of the mercury, 

 did not arise from a stoppage of the battery current ; for by placing 

 a voltameter in the circuit, conduction was found freely, whilst no 

 movements of the mercury could be seen. The strength of the in- 

 duced currents increased with the loudness of the sounds. It ap- 

 pears, therefore, that the intermittency was not produced by simple 

 electrolysis of the solution, but by the vibrations, and was not limited 

 to such vibrations as produced audible sounds. 



Influence of Coils of Wire in the Circuit. 



34. Experiment 1 . A coil of copper wire containing 1 54 feet of size 

 " No. 26" was included in the circuit with eight Smee's elements (4) 

 immersed 8^- inches, and a phonetic vessel : without the coil the 

 vibrations were very fine, and the sound acute and loud ; but with 

 the coil they were coarse, and the sound base and feeble. Experi- 

 ment 2. A coil containing 2/2 feet of "No. 19" copper wire in- 

 cluded in the circuit produced similar effects. And, Experiment 3. 

 A ring of soft iron weighing 27 ^ pounds, outer diameter 1 2 inches, 

 inner diameter 8 inches, formed of cylindrical metal 2 inches thick, 

 had wound upon it in the manner of an electro-magnet 152^- feet of 

 four parallel and separately-insulated copper wires, size "No. 17." 

 Six pairs of plates, immersed 8-J- inches, were connected in circuit, first 

 with one length, and then with two, three, and four continuous lengths 

 of the wire ; every additional length of the wire made the vibrations 



