352 Professor Daniell on the 



electrode of copper, or of zinc, as in the ordinary cells of the 

 battery. 



Further experiments showed that whenever dilute sul- 

 phuric acid is used, there is a transfer of acid towards the 

 zincode, and the determination of the proportions in which 

 such a transfer occurs led to some curious results, to which 

 we must presently revert. 



In order, however, to remove the ambiguity which might 

 thus possibly be conceived to arise from the employment of 

 dilute sulphuric acid as the measure of the electrolytic force, 

 the following arrangement was substituted for the ordinary 

 voltameter: a green glass tube (into the bottom of which, as 

 platinode, was welded a weighed platinum wire) was filled with 

 chloride of lead, maintained in a state of fusion by a spirit- 

 lamp ; the corresponding zincode was formed of plumbago. 

 At the termination of the experiment the tube was broken, 

 the wire and adhering button of lead weighed ; and the result 

 showed that " the same current which is just sufficient to re- 

 solve an equivalent of chloride of lead, which is a simple elec- 

 trolyte unaffected by any associated composition, into its equi- 

 valent ions, produces the apparent phenomena of the resolu- 

 tion of water into its elements ; and at the same time of an 

 equivalent of sulphate of soda into its proximate principles." 



Aqueous solutions of the chlorides were next tried, as the 

 simple constitution of this class of salts promised to throw light 

 upon the nature of the electrolysis of secondary compounds. 



A weighed plate of pure tin was made the zincode of the 

 double cell, which was charged with a strong solution of 

 chloride of sodium, and a tube of fused chloride of lead, as before, 

 included in the circuit ; not a bubble of gas appeared on the 

 tin electrode, and no smell of chlorine was perceptible, but 

 hydrogen in equivalent proportion to the quantity of tin dis- 

 solved was given off at the platinode, and the cell contained 

 an equivalent proportion of free soda. One equivalent of 

 lead was reduced in the voltameter tube. 



Muriate of ammonia treated in the same way gave precisely 

 similar results, proving it to be " an electrolyte, whose simple 

 anion was chlorine, and compound cathion nitrogen with 4 

 equivalents of hydrogen. Its electrolytic symbol, therefore, 

 instead of being 



(CI + H) + (N + 3 H), is CI + (N + 4 H)." 

 Strikingly confirming the hypothesis of Berzelius of the base 

 (N + 4 H) called ammonium. 



In discussing the results of all these experiments, we must 

 bear in mind the fundamental principle, " that the force which 

 we have measured by its definite action at any one point of a 



