Career
But for his untimely death, he might have been a Nobel laureate. He has been called "the unsung hero of radiocarbon dating" by Eric Willis, the first director of the radiocarbon-dating laboratory at the University of Cambridge. In 1958, de Vries showed that baffling anomalies in the carbon-14 dates, observed by Willard Frank Libby for Egyptological samples, were in fact systematic anomalies on a global scale, represented in the carbon-14 dates of tree rings.
This phenomenon has been called the "de Vries effect".
The correspondence with tree rings, which can be counted (one ring for each year), led to a recalibration of radiocarbon dating that was a large improvement in the accuracy. De Vries committed suicide in 1959, after murdering a former analyst (Anneke Hoogeveen), with whom he was in love but who had become engaged to another manitoba
