Small influentially taught Jefferson. Franklin, a great friend both before and after, spent nine months together with him in Paris. Jefferson sent Buffon, whom he’d visited in Paris, the rather worn skin and bones of a moose so he could have it stuffed (Buffon argued for the superiority of old-world species). Humboldt was a dear friend, spending several weeks with Jefferson, while Paine walked arm-in-arm with him on Washington streets. Paine and Priestley (both close friends) and Peale and Rittenhouse were important members of his literary and intellectual circle. Condorcet was among his other correspondents.
As a young man keen to get himself known during and following WWl, he got to know Picasso, Braque, Reverdy, Salmon, Jacob, Cendrars and particularly Apollinaire (he edited Reverdy and Jacob). His sidekick Pia, and Arland, were among those who stayed close to him. He visited his admired Ensor in Ostend, and collaborated on an abortive piece with Varèse. Mac Orlan received him, Paz met him in civil-war Spain, and Resnais married his daughter. He went to Berlin with Gide (Hitler refusing to see them), and to the USSR with Aragon and Nizan. Camus, then unknown, corresponded with him, and admired him greatly.
Price and Priestley moved in the same radical circles in London, while Priestley and Hume both welcomed him as a guest. He assisted at Voltaire’s masonic initiation. Pringle was a frequent travelling-companion in Europe; Walpole called on the two in Paris, where Franklin was a regular at d’Holbach’s salon. Casanova sat next to him, listening to him discussing aeronautical balloons with Condorcet (who also later persuaded him that slavery and racial inequality were corrupt). Lavoisier and Franklin fixed the lightning-conductors Franklin had invented to a Paris church; Boswell admiringly quoted him to Johnson.