[6] L. J. Henderson: The Fitness of the Environment, 1913.
[7] Henderson: loc. cit., p. 138.
[8] F. R. Moulton: Introduction to Astronomy, 1916.
[9] Moulton: loc. cit.
[10] James Croll: Climate and Time, 1876.
[11] T. C. Chamberlin: An attempt to frame a working hypothesis of the cause of glacial periods on an atmospheric basis; Jour. Geol., Vol. VII, 1899, pp. 545-584, 667-685, 757-787.
T. C. Chamberlin and R. D. Salisbury: Geology, Vol. II, 1906, pp. 93-106, 655-677, and Vol. III, pp. 432-446.
S. Arrhenius (Kosmische Physik, Vol. II, 1903, p. 503) carried out some investigations on carbon dioxide which have had a pronounced effect on later conclusions.
F. Frech adopted Arrhenius' idea and developed it in a paper entitled Ueber die Klima-Aenderungen der Geologischen Vergangenheit. Compte Rendu, Tenth (Mexico) Congr. Geol. Intern., 1907 (=1908), pp. 299-325.
The exact origin of the carbon dioxide theory has been stated so variously that it seems worth while to give the exact facts. Prompted by the suggestion, of Tyndall that glaciation might be due to depletion of atmospheric carbon dioxide, Chamberlin worked up the essentials of his early views before he saw any publication from Arrhenius, to whom the idea has often been attributed. In 1895 or earlier Chamberlin began to give the carbon dioxide hypothesis to his students and to discuss it before local scientific bodies. In 1897 he prepared a paper on "A Group of Hypotheses Bearing on Climatic Changes," Jour. Geol., Vol. V (1897), to be read at the meeting of the British Association at Toronto, basing his conclusions on Tyndall's determination of the competency of carbon dioxide as an absorber of heat radiated from the earth. He had essentially completed this when a paper by Arrhenius, "On the influence of carbonic acid in the air upon the temperature of the ground," Phil. Mag., 1896, pp. 237-276, first came to his attention. Chamberlin then changed his conservative, tentative statement of the functions of carbon dioxide to a more sweeping one based on Arrhenius' very definite quantitative deductions from Langley's experiments. Both Langley and Arrhenius were then in the ascendancy of their reputations and seemingly higher authorities could scarcely have been chosen, nor a finer combination than experiment and physico-mathematical development. Arrhenius' deductions were later proved to have been overstrained, while Langley's interpretation and even his observations were challenged. Chamberlin's latest views are more like his earlier and more conservative statement.