56 THEORY OF LIGHT. 



metallic or otherwise, that the positive is determined to the posi- 

 tive electrode, or anode, while the hydrogen is invariably evolved 

 at the negative electrode or cathode, as primary results; that 

 when secondary results occur, and that nitrogen is found to ap- 

 pear at either of the electrodes, in conjunction with oxygen at 

 the one, or with alkalies at the other, it appears to be go- 

 verned by attractive influences to which it submits. But in the 

 case of ammonia (rendered a better conductor by the addition of 

 sulphate of ammonia), while hydrogen is evolved at the negative 

 electrode, nitrogen is determined at the positive electrode ; and 

 further, that in all cases of decomposition hydrogen is evolved 

 definitely from the negative electrode, and evidenced either in 

 its discharge in a pure state, or contributing to the reforma- 

 tion of metals determined to the same electrode, and is to be 

 found in their composition when their oxides have been sub- 

 mitted to experiment by electro-chemical action. 



The red ray (or oxygen) is therefore determined to one elec- 

 trode, while the blue ray (hydrogen) is evolved from the other, 

 and the yellow ray (nitrogen), whose proper electrode is the 

 same as the blue (hydrogen) ray, is, on occasions, for instance, 

 where a chloride of calcium or soda is under investigation, the 

 chlorine flies to tine positive, and the base to the negative elec- 

 trode. 



Chlorine is, from its appearance, color, and properties, a com- 

 pound of nitrogen in maximum, hydrogen in minor proportions, 

 and (perhaps) oxygen in minimum, and the basis of all the 

 alkalies is nitrogen, and they are consequently determined to 

 the negative electrode ; while the metals, holding in their reduced 

 state hydrogen in excess, proceed to the same electrode, and 

 oxygen separated from oxides, acids, and water, or aqueous or 

 acid solutions, go to the positive electrode. And where any 

 deviation occurs, as in secondary results, it will be found that 

 any partial quantities of hydrogen and nitrogen found to issue 

 from the positive pole, must be in a compound state, or in con- 

 junction with oxygen or compounds containing it. 



