Royal Institution. S79 



fly off or pass through non-conducting media: thus the electri- 

 city of the common electrical machine is possessed of great in- 

 tensify, hecause it passes in long sparks through air ; hut its 

 quantity is inconsiderable, for the whole is at once withdrawn 

 from the conductor, 



Mr. Brande next proceeded to the discoveries of Galvani and 

 Volta: the former had ascertained that, on bringing zinc and 

 silver in contact with the nervous and muscular parts of recently 

 killed animals, violent spasmodic affections ensued ; and he 

 formed an unsatisfactory hypothesis to account for the effect : 

 but the subject soon fell into the more able hands of Volta, find 

 became proiluctive of infinitely important conseijuences, not 

 merely as influencing the theory of electrical action, but as ex- 

 tending the boundaries of that department of science, and ulti- 

 mately of chemical philosophy- 



Volta referred the effects upon the frog, to the excitation of 

 electricity by the contact of the metals, and devised the method 

 of accumulating the electricity thus excited, by the alternate ar- 

 rangements of two different metals and moistened paper. The 

 Professor having pointed out the improvements which had suc- 

 cessively taken place in the Voltaic apparatus, stated that its ac- 

 tion appeared to depend upon the disturbance of the electrical 

 equilibrium bv the two metals, rendering one positive and the 

 other negative ; and upon its increase by induction throughout 

 the series. 



The electrical phaenomena of the Voltaic pile were fiirther il- 

 lustrated by the construction and effects of the electric column of 

 Mr. de Luc, in which an active electrical arrangement is pro- 

 duced by alternations of dry paper, zinc, and silver. The con- 

 sideration of the general powers and chemical effects of the Vo'- 

 taic instrument Mr. Brande deferred to a future lecture, when he 

 siiould employ the large apparatus, consisting of 2000 series, 

 constructed in the Royal Institution under the direction of Sir 

 M. Davy. 



The lecture concluded with some general observations upwi 

 the advances which had been made in the theory of electrical 

 action ; a branch of science, in which, notwithstanduig the ta- 

 lents and al)ilities displayed in its prosecution, there remained 

 many recesses unexplored, and many fountains unexhausted. 



Having ii) his former lecture described tlie structure and ope- 

 ration of the Voltaic instrument, Mr. Brande proceeded in his 

 I4th lecture on Saturday, May 27th, to consider the methods 

 of increasing the quantity and intensity of its electricity. He 

 spoke first of chemical action, and exhibited several experi- 

 ments, in which the power of ignition in the battery was in- 

 creased proportionally to the action of the intervening fluid upon 



the 



