Unidad documental simple 107 - Letter from George Airy

2 pp.

Royal Observatory Greenwich - GA's 'people have brought up the pendulum-calculations to the final stage, and the result is - 1. The pendulums have stood so well as to give very great confidence in the accuracy of result. 2. The gravity at the bottom of the mine (reputed 1260 feet) is greater than at the top by 1/19190 part...This gives density nearly = 2.7 x density of coal measures, which is more than I expected'.