454 The Rev. J. W. MacGauley on some remarlmhle Results 



and discs were intended merely as a convenient means of coil- 

 ing the wire and submitting bars of iron or of steel to the ac- 

 tion of the helix. The corresponding extremities of the coils 

 were soldered to two thick pieces of copper wire, which were 

 made to dip respectively into two cups of mercury, forming a 

 connexion between the poles and a calorimotor 1 foot square, 

 double cell, charged with 400 drachuis of water and 12 of 

 muriatic acid. Wires lead from the same cups of mercury to 

 vessels containing a solution of common salt, into which the 

 hands are dipped for the purpose of obtaining a shock when 

 battery connexion is broken. Though the wire, for conve- 

 nience, is coiled upon brass, it is immaterial how it is ar- 

 ranged. I have thrown it into a heap, and believe the effect 

 was equally powerful. 



The spark and shock must be produced qfte?- battery com- 

 munication is broken, because while it exists, every electrical 

 effect must be prevented by the helix, as it affords a good con- 

 ducting communication between the copper and zinc of the 

 battery. Inclosing a bar of soft iron in the helix diminishes 

 the effect. 



2nd. The size of the battery, only within certain limits, af- 

 fects the spark and shock. In constructing a galvanic helix, 

 or a system of such helices, it is evident that the length of 

 the wire must be limited, on account of its imperfect con- 

 ducting power. We must therefore, to produce a consider- 

 able effect, multiply the helices : on the other hand, if the bat- 

 tery be very small, a minute subdivision of its electricity among 

 so many wires may render the portions in each insufficient for 

 any considerable disturbance of electrical equilibrium. The 

 number of the coils and their lengths must therefore be regu- 

 lated by the size of the battery and the conducting power of the 

 wire. 



3rd. Those properties of the electro-galvanic helix are 

 strongly confirmatory of the theory I venturetl to advance be- 

 fore the British Association on the nature of magnetism : 

 "That its existence does not depend on the continuance of 

 electrical currents; that continued electrical currents are not 

 the consequence of magnetization ; and that magnetism is mere 

 electrical excitement." For if electrical currents were essen- 

 tially connected with magnetism, and if we can obtain a shock 

 and spark — the acknowledged indications of a current by a 

 simple helix — how much more should we obtain these indica- 

 tions when both causes are simultaneously in action, either of 

 which, of itself, were sufficient for their production ! Yet the 

 existence of magnetism within the helix proportionably injures 

 its effect. Magnetism is merely induced electricity, for it is 



