> > Dear Julio, > > What is the story? > > In Carl Boyer's 2nd Edition of "History of Mathematics", Wiley, 1991, > pg. 420: > "... Jean Bernoulli signed a pact under which, in return for a regular > salary, he agreed to send L'Hospital his discoveries in mathematics, > to be used as the marquis wished." > The story is unreferenced. > > Peace, > > Don Cook > > P.S. I have just read Avinoam Mann's letter with the same quote. Still, what > is the correct story? >
Boyer mentions letters between L'Hospital and Bernoulli. So does Coolidge, in _The mathematics of great amateurs_, though Coolidge does not mention any commercial aspect. Moreover, from Coolidge's quotes it seems that the letters do not specifically say that B. discovered `L'Hospital's rule_', but they suggest it. So it appears that to decide matters one has to go back to the correspondence. Two books are mentioned: O.J.Rebel, Der Briefwechsel zwischen Johan Bernoulli und den Marquis L'Hospital, Bottrop i.w. 1934; Coolidge refers to pp. 147-8, 161, 163; and O.Spiess (editor), Der Briefwechsel von Johann Bernoulli, vol. 1, Basel, Birkhaeuser 1955.