164- Dr. Faraday's Experimental Researches in Electricity. 



meanings are perhaps right, they are only hypothetical, and 

 may be wrong ; and then, through a very imperceptible, but 

 still very dangerous, because continual, influence, they do 

 great injury to science, by contracting and limiting the ha- 

 bitual views of those engaged in pursuing it. I propose to 

 distinguish these bodies by calling those anions* which go to 

 the anode of the decomposing body; and those passing to the 

 cathode, cations-f; and when I have occasion to speak of these 

 together, I shall call them ions. Thus, the chloride of lead 

 is an electrolyte, and when electrolyzed evolves the two ions, 

 chlorine and lead, the former being an anion, and the latter 

 a cation. 



666. These terms being once well defined, will, I hope, in 

 their use enable me to avoid much periphrasis and ambiguity 

 of expression. I do not mean to press them into service more 

 frequently than will be required, for I am fully aware that 

 names are one thing and science another J. 



667. It will be well understood that I am giving no opinion 

 respecting the nature of the electric current now, beyond 

 what I have done on a former occasion (283. § 517.) ; and that 

 though I speak of the current as proceeding from the parts 

 which are positive to those which are negative (663.), it is 

 merely in accordance with the conventional, though in some 

 degree tacit, agreement entered into by scientific men, that 

 they may have a constant, certain, and definite means of re- 

 ferring to the direction of the forces of that current. 



f iv. On some general Conditions of Electro-chemical De- 

 composition. 



669. From the period when electro-chemical decomposition 

 was first effected to the present time, it has been a remark, 

 that those elements which, in the ordinary phenomena of 

 chemical affinity, were the most directly opposed to each other, 

 and combined with the greatest attractive force, were those 

 which were the most readily evolved at the opposite extre- 

 mities of the decomposing bodies (549.). 



670. If this result was evident when water was supposed to 

 be essential to, and was present, in almost every case of such 

 decomposition (472.), it is far more evident now that it has 

 been shown and proved that water is not necessarily con- 



♦ uvtov that which goes up. (Neuter participle.) 



+ KocTtov that which goes down. 



\ Since this paper was read, I have changed some of the terms which 

 were first proposed, that I might employ only such as were at the same 

 time simple in their nature, clear in their reference, and free from hy- 

 pothesis. 



§ See Lond. and Edinb. Phil. Mag. vol. iii. p. 1GG. — Edit. 



