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Abstract The first measurements to determine the composition of the atmosphere were made at least 180 years ago, but chemists worked more than a century before they obtained really accurate values for the amount of carbon dioxide in the air. In the following: a brief review is given of the present state of knowledge concerning the variations of atmospheric carbon dioxide, together with some observations which appear to show that the amount of this gas in the air has increased of late years.
G. S. Callendar (Tue,) studied this question.