PRIMARY AND SECONDARY RESULTS OP ELECTROLYZATION. 101 



varying with the strength of the acid, the intensity of the current, and other circum- 

 stances. 



774. Acetates. — One of these has been referred to already, as affording only se- 

 condary results relative to the acetic acid (749.). With many of the metallic acetates 

 the results at both electrodes are secondary (746. 750.). 



Acetate of soda fused and anhydrous is directly decomposed, being, as I believe, a 

 true electrolyte, and evolving soda and acetic acid at the cathode and anode. These, 

 however, have no sensible duration, but are immediately resolved into other sub- 

 stances ; charcoal, sodiuretted hydrogen, &c., being set free at the former, and as far 

 as I could judge under the circumstances, acetic acid mingled with carbonic oxide, 

 carbonic acid, &c., at the latter. 



77^' Tartaric acid.—VxxvQ solution of tartaric acid is almost as bad a conductor as 

 pure water. On adding sulphuric acid to it, it conducted well, the results at the 

 positive electrode being primary or secondary in different proportions, according to 

 variations in the strength of the acid and the power of the electric current (752.). 

 Alkaline tartrates gave a large proportion of secondary results at the positive elec- 

 trode. The hydrogen at the negative electrode remained constant unless certain me- 

 tallic salts were used. 



77^' Solutions of salts containing other vegetable acids, as the benzoates ; of sugar, 

 gum, &c., dissolved in dilute sulphuric acid ; of resin, albumen, &c., dissolved in 

 alkalies, were in turn submitted to the electrolytic power of the voltaic current. In 

 all these cases, secondary results to a greater or smaller extent were produced at the 

 positive electrode. 



777' In concluding this division of these Researches, it cannot but occur to the 

 mind that the final result of the action of the electric current upon substances placed 

 between the electrodes, instead of being simple may be very complicated. There are 

 two modes by which these substances may be decomposed, either by the direct force 

 of the electric current, or by the action of bodies which that current may evolve. 

 There are also two modes by which new compounds may be formed, i. e. by combi- 

 nation of the evolving substances whilst in their nascent state (658.), directly with 

 the matter of the electrode ; or else their combination with those bodies, which being 

 contained in, or associated with, the decomposing conductor, are necessarily present at 

 the anode and cathode. The complexity is rendered still greater by the circumstance 

 that two or more of these actions may occur simultaneously, and also in variable pro- 

 portions to each other. But it may in a great measure be resolved by attention to 

 the principles already laid down (747-) • 



778. When aqueous solutions of bodies are used, secondary results are exceedingly 

 frequent. Even when the water is not present in large quantity, but is merely that of 

 combination, still secondary results often ensue : for instance, it is very possible that 

 in Sir Humphry Davy's decomposition of the hydrates of potassa and soda, a part of 

 the potassium produced was the result of a secondary action. Hence, also, a frequent 



