50 NOMOS. 



cup into the cup c, without combining with the acid. 

 But this is not the explanation, and that it is not 

 we may see by modifying the experiment. The three 

 cups are still placed side by side, and connected by 

 similar pieces of lamp- cotton; only now these pieces 

 are soaked in solution of chloride of barium instead 

 of sulphate of potass. The central cup is still filled 

 with sulphuric acid ; but the cups A and C are filled 

 with the same solution as that with which the con- 

 necting pieces are soaked chloride of barium. On 

 passing the current in the same direction through the 

 cups connected and charged in this manner, the 

 solution in the cups A and c is decomposed, and the 

 alkaline earth, baryta, endeavours to find its way 

 through the central cup into the cup c, as did the 

 alkali in the last experiment. It endeavours to do 

 this, but it does not get beyond the central cup. It 

 does not get beyond the central cup, because the 

 alkaline earth, baryta, forms an insoluble precipitate 

 with the sulphuric acid contained in this cup. Instead 

 of there being no apparent change, as in the other 

 experiment, the sulphuric acid in the central cup 

 becomes milky with this precipitate as the current 

 passes. This fact, then, shows very clearly that 

 there was no suspension of chemical affinities in the 

 former experiment; and it affords the strongest 

 possible presumption that the soda passed through 

 the acid in the central cup, not in violation of chemi- 

 cal laws, but in obedience to these laws; that is, 

 by first combining with, and then leaving the acid, 

 in direct obedience to the overruling chemical affini- 

 ties of the current itself. 



