"I Refute It Thus"

After we came out of the church, we stood talking for some time together of Bishop Berkeley's ingenious sophistry to prove the non-existence of matter, and that every thing in the universe is merely ideal. I observed, that though we are satisfied his doctrine is not true, it is impossible to refute it. I never shall forget the alacrity with which Johnson answered, striking his foot with mighty force against a large stone, till he rebounded from it, 'I refute it thus.'

 Davy VS Gay-Lussac in the Race to Discover Iodine

He was warmly received by Cuvier, Ampère and Berthollet, but got into an awkward priority dispute with the gifted young chemist Joseph Gay-Lussac. Gay-Lussac, Davy’s exact contemporary, had made a popular name in France with his intrepid ballooning exploits, and had been hard on Davy’s heels with potassium and sodium experiments. Both were now given by the Académie des Sciences a newly isolated substance to analyse: a strange violet crystal recently found as a byproduct of gunpowder man...