Do others not think this thread is surrealistic? Certainly so many years after Kuhn
(recall his Lavoisier and Priestly on the first discovery of oxygen) can we not agree
that, as the historian of science Ted Porter has noted, "In the history of science <a
fortiori economics> the idea of a precursor has long been regarded as a category mistake."
  
What is the need to locate "first use" a symptom of? Is this part of the older idea, from
the cold war period, that of course the Russians invented "beisbol" before any American
played the game, or that airplanes flew in Russia years before the Wright Brothers. Are we
not bored by "Borel invented game theory before von Neumann and MOrganstern"? Are we
seriously interested as historians in discussing that while equilibrium may have been in
Marshall, it was in France first. Or is it the claim that it really is an earlier Italian
idea? But does not Ecclesiates present the equilibrium cycle in interesting detail? Would
anyone like to speak up for the Baylonians, since the seventeenth article of the Code of
Hammurabi states ...
  
The noted historian of statistics Steven Stigler has a famous paper on Stigler's Law which
states that every important idea is named after someone who didn't understand it. Here of
course "understanding" is OUR understanding, as of today.
  
Characterizing the notion of equilibrium historically is non-trivial. If one is thinking
of equilibrium celestially in terms of planetary motion, one's idea, one's entire
conceptual scheme, is different from that of one who is "thinking biologically" in a
different period. For a perspective on one element of this see Cynthia Eagle Russet's The
Concept of Equilibrium in American Social Thought.
  
Writing about the historical use of "equilibrium" means contextualizing the term in a
variety of its contemporaneous uses, which is different from doing a word search backwards
in time. A history is different from a genealogical dictionary.
  
E. Roy Weintraub