H. E. Suess I. Friedman A. E. Bainbridge 1961 <p><span>IN a recent communication, Bishop and Taylor</span>¹<span>&nbsp;express the opinion that the tritium concentration of free hydrogen in the atmosphere has been rising over the past ten years, with a doubling time of approximately 18 months. The authors suspect that artificial tritium was released into the atmosphere several years before the Castle test series in 1954, which is commonly assumed to have led to the first pronounced rise in the tritium concentration of terrestrial surface water. Bishop and Taylor's communication includes a diagram of the logarithms of all the experimentally determined tritium values in free atmospheric hydrogen plotted against time. The plot shows that the values follow a straight line that includes the first value obtained by Faltings and Harteck</span>²<span>&nbsp;on atmospheric hydrogen collected in 1948.</span></p> application/pdf 10.1038/192648a0 en Nature Publications Isotopic composition of atmospheric hydrogen and methane article