These are principally letters from Airy relating to his publications, his position as Astronomer Royal of England, with mentions of topics such as: electrical experiments, magnets, Observatoire de Paris, stars, and telescopes. One interesting group of documents was put together (1889) by George May of the Harton Colliery at South Shields. This relates to Airy's pendulum experiments at Harton Pit in 1854 to measure the density of the earth. The correspondence includes about 26 letters between Airy and the mine owners, C.W. Anderson and William Anderson. Airy gives instructions and draws diagrams both before and during the experiments, and there are subsequent letters seeking information needed for additional calculations. Included are news clippings, a pamphlet by Airy ("Lecture on the Pendulum-Experiments at Harton Pit." London, 1855), and a piece of the wire used in the experiment.