Philosophical Society of Washington was founded on March 13, 1871. It was preceded by garings at home of Joseph Henry, great scientist whose discoveries laid foundations for advances in magnetism and electromagnetism. Since 1887 it has met at Cosmos Club, in whose founding Philosophical members played a large part. In 1878, when Cosmos was founded, re was fear that Philosophical would start an alternative club, so all present members of Philosophical were invited to join as founding members of Cosmos. This 1881 volume demonstrates extraordinary history of Society. Noting that more than 200 consecutive meetings had been held, it includes an address by E.M. Gallaudet on deafness, by John Wesley Powell on limits to use of data, and no less than two addresses by Alexander Graham Bell. No or society in Washington has maintained such high standards for so many years. Its Friday night garings have survived turbulence of war and depression and retain ir relevance: 2234th meeting in spring of 2014 presented Nobel laureate Craig Mello.