Re: Why is the letter 'S' used for entropy?

Entropy, the thermodynamic state function that drives reactions to equilibrium, was defined by Rudolf Clausius in the early 1860's. He was also responsible for chosing the letter S to represent entropy in thermodynamic equations. The consensus, as I have found, in the thermodynamic community is that Clausius' choice of S was purely arbitrary. This leads me to suspect that S was chosen because it lies between Q (Heat) and T (Temperature) - the variables which define entropy - and R (the ideal gas constant) was already taken. That way the equation for entropy and its components would have (nearly) consecutive letters:

       dQ
dS =  ---
       T

This is still a guess, since Clausius died without explaining his choice, but it fits better than most other explanations I have heard.