Letter from Rollo Appleyard, The Athenaeum, Pall Mall, to Sir William [Barrett] Thanks Barrett for the papers and letter of Dr Brown. Brown's letter confirms that the effect in the case of a chalk cylinder was a decrease in 'stiction'. The idea that a Trevelyan rocker might be acted upon by Crookes' Force is new and he asks Barrett if an experiment at the Royal Institution might be possible. An integral arrangement sketch of the air pump experiment appears in the letter. 29 March 1924