PROFESSOR IN BERLIN 335 



Since the loss of mechanical energy by friction produces 

 heat, while gain of mechanical energy produces loss of heat, and 

 since further the sum of energy lost and gained is proportional 

 to the sum of the heat gained or lost, heat must be regarded 

 as a form of energy, and it follows that every particle of a warm 

 body must always be moving in a constantly varying direction, 

 so rapidly that it undergoes little or no alteration of place in 

 the body. But if so, a part of the energy of a warm body 

 must be in the form of kinetic energy, and since every mode of 

 energy can be transformed into heat, it follows that the energy 

 can be measured in the form of heat. But from the law of the 

 conservation of energy it is impossible to determine whether 

 work can be unconditionally transformed into heat energy, and 

 the latter, conversely, into work, and the same for all the other 

 natural forces. Helmholtz accordingly turned in the first place 

 to the determination of these important theoretical and practical 

 relations. He endeavoured to ascertain how large a portion of 

 the heat developed in a galvanic cell by chemical processes 

 reappears as current energy, and arranges the forms of energy 

 in different grades, according as they are more or less com- 

 pletely capable of conversion into mechanical work. 



In the fundamental papers on 'The Thermodynamics of 

 Chemical Processes ' (communicated to the Berlin Academy on 

 February 2 and July 27, 1882), he develops in mathematical 

 form the relations between the laws of heat, of electricity, and 

 of chemical phenomena, from which an identity of chemical 

 valencies and electrical potentials of the atoms appears probable, 

 so that the electrochemical processes would seem to be an 

 ordered motion of the atoms and molecules, directed along the 

 co-ordinates of space, while heat is a similar process, but un- 

 ordered. 



The question as to the connexion between the electromotive 

 force of batteries with unpolarizable electrodes, and the chemical 

 changes which take place in them, led Helmholtz to the more 

 general question as to what portion of the energy present in 

 a body can be converted into other forms of work, and carried 

 him on to his work on the thermo-dynamics of chemical 

 processes, which again were only the prelude to his great 

 researches on monocyclic systems. Owing to the introduction 

 of potential energy, which Helmholtz had designated earlier as 



