Equations of "rational mechanics" and general equilibrium Vilfredo Pareto, referring to the equations that determine equilibrium, wrote:


  These equations do not seem new to me, they are old friends. They are
  the equations of rational mechanics.


This quotation appears in the paper On the Economic Phenomenon: A Reply to Benedetto Croce he doesn't make clear what specific equations he's referring to. As someone with a physics background I am curious if anyone knows/could guess what he is referring to.
Pareto believed economics could be studied with the same mathematical rigor as physics, so it's quite possible he was speaking to the similarities between mathematical economics and classical mechanics (the latter of which was just coming into its own in the early 1900s).  I'm a physicist by training too, and those similarities helped me rapidly cover a great deal of ground my colleagues in economics had to learn fresh, so your intuition makes sense to me.