Carbon-14 Content of 18th- and 19th-Century Wood: Variations Correlated with Sunspot Activity

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Science  30 Jul 1965:
Vol. 149, Issue 3683, pp. 533-534
DOI: 10.1126/science.149.3683.533


A series of carbon-14 measurements of 18th- and 19-century wood revealed an excellent correlation between the variations in carbon-14 content and average sunspot activity. It seems probable, therefore, that the predominant cause of the short-term fluctuations in carbon-14 activity is the variability of solar activity.