Copy letter, from Sir John Herschel to Pierre Simon Laplace, dated at London Copy of letter, copied as part of the correspondence project led by Colonel John Herschel FRS following the death of his father. Henry Kater's triangulation survey of north Scotland. Edward Sabine's study of pendulum lengths at various latitudes. François Arago did not receive letters from John Frederick William Herschel and Francis Baily. Comments on rumor of [Isaac] Newton's madness. John Frederick William Herschel plans to reduce transit observations of fixed stars at Greenwich since [James] Bradley's time. Are French and other astronomers in agreement on common system of reductions? Will visit Paris next month. Observed curious phenomena in voltaic electricity. 18 March 1824