Prof. Ostwald on Chemical Action at a Distance. 153 



kind for the representation of natural occurrences, and the 

 cause thereof lies in the following. 



The different forms of energy may be, as is known, always 

 resolved into two factors, one of which possesses the pro- 

 perty that, in a system with a definite kind of energy, a con- 

 dition independent of the time may obtain only when this, 

 which Helm calls the intensity factor, has the same value 

 everywhere in the system. Conversely, anything happens 

 in the system only under the condition that the values of this 

 factor at two places thereof are different. Difference of the 

 intensity-factor is therefore the cause that anything happens, 

 and every difference of this kind represents a " Tendency " 

 or a Inclination " of the system to equalize the difference. 

 Now there are possibilities, as shall in another place be more 

 fully explained, of hindering this equalization by the bringing 

 to bear of appropriate, opposing intensity-differences of another 

 form of energy ; these are exactly the cases in which the 

 above-mentioned expressions " Tendency " and " Inclination" 

 clearly present themselves, because the action is ready to 

 take place at any time when the hindrance present is re- 

 moved. In this sense, that the system of metals, electrolytes, 

 &c. at hand contains differences of intensity of chemical 

 energy, which are compensated by corresponding opposing 

 differences of electrical intensity, or of potential, and which 

 assert themselves first when, by establishment of the electric 

 conduction, the latter are made to vanish, — in this sense have 

 tendency and inclination been used in the preceding, and, after 

 this explanation, the further use of these terms may well 

 appear permissible. 



If we now turn back to the subject under consideration, we 

 see that the dissolving of metals is in all cases in so far electric, 

 as it depends upon the changing of the metals into (electri- 

 cally charged) ions. The marked activity of the metals in 

 the development of electric currents depends, on the one hand, 

 upon their capacity to undergo this change, on the other 

 upon their capacity of " metallic " conduction. Further, 

 when currents cannot be developed because the necessary 

 conductors are wanting, the quantity of energy corresponding 

 to the change may assume the form of heat ; as occurs, for 

 example, with the dissolving of metals which do not separate 

 hydrogen, such as copper, silver, bismuth, &c, in nitric acid 

 or aqua regia. In this case the question is also one of the 

 replacement, by metal ions, of the hydrogen ions present ; 

 but since the metal is not able to take the electricity neces- 

 sary for the change directly from the hydrogen, a cause must 

 be present to assist this action. Here, for example, the oxygen 



