On 13 August 1894, John William Strutt, 3rd Baron Rayleigh and William Ramsay announced the detection of a new gas in the atmosphere. On 31 January 1895 they made a full report to the Royal Society on the new gas, argon. In addition, William Crookes, who had been asked to examine a sample, presented on the spectra of argon, reported that argon displayed two distinct spectra. In this way, Crookes identified the first known sample of terrestrial helium and established its correspondence to observations of solar helium. The discovery of argon and of helium led to identification of the noble gases and the reorganization of the periodic system.