THEORY OF GALVANISM. 107 



state or modification which we style galvanic. With 

 respect to the nature of this chemical change, experi- 

 mentalists are generally agreed : as to the metals, 

 it consists in the oxidation of that metal which 

 possesses the strongest attraction for oxygen ; and 

 with respect to the fluid interposed between the 

 rnetals, it consists in its decomposition, the oxygen- 

 ous part being attracted to the most oxidable me- 

 tal, and the alkaline to that which is the least 

 oxidable. Although, as I have already had occa- 

 sion to remark, there are various galvanic combina- 

 tions into which only one metal enters, or even 

 some entirely without metals, yet, as the most 

 powerful and complete circle is that which con- 

 sists of two metals with a fluid interposed, I shall 

 confine my illustrations to this form of the ap- 

 paratus. 



We may consider it as proved by a number of Galvanic 

 experiments, which have been stated in the first onow Po- 

 part of this article, that the electricity, as it is tensit y 

 evolved by the different galvanic combinations, 

 always exists in what has been styled a state of 

 low intensity ; and that, to whatever extent we 

 increase the apparatus, and however powerfully it 

 acts, still the intensity is but little augmented. 

 Unfortunately it is still a doubtful point of theory, > 

 upon what the intensity of electricity depends, or 

 in what it precisely consists. Some writers have Remarks / 

 ascribed it to a greater or less concentration of the n c "* 

 fluid ; some to a difference in the velocity of its sit ?- 

 motion, or in the strength of its affinity for the 



