Letter, from Ismael Boulliaud to Henry Oldenburg, dated at Paris Autograph letter concerning Dr Wallis's 'Arithmetica infinitorum' and Boulliaud's observations of the lunar eclipse on 11 January (Table published in 'Philosophical Transactions', vol 9, no 111, p 238) Read to the Royal Society on 11 February 1675 7 February 1675