The blackboard was rescued with another board by dons (including the chemist E. J. Bowen, zoologist Gavin de Beer, and historian of science Robert Gunther) and formally donated by the Warden of Rhodes House, Sir Francis James Wylie. The writing on the blackboard, although ephemeral in nature, is of historic interest because the equations displayed are taken from a model of the universe proposed by Einstein in May 1931 known as Friedmann–Einstein universe. The last three lines on the blackboard are estimates of the density of matter in the universe ρ, the radius of the universe P and the timespan t of the expansion of the universe respectively. It has recently been shown that these estimates contain a systematic numerical error.