Manfred Eigen, who shared the 1967 Nobel Prize in Chemistry for devising a method to time chemical reactions that had been thought too swift to measure, died on Feb. 6 in at his home in Göttingen, Germany. He was 91.

His death was confirmed by the Max Planck Institute for Biophysical Research, which Dr. Eigen founded in 1971.

Dr. Eigen was a young scientist at the University of Göttingen in the early 1950s when, while studying extremely rapid chemical reactions — sometimes faster than a billionth of a second — he decided to figure out a way to time them. He had been inspired, and vexed, by a line in a textbook that described certain chemical reactions as “immeasurably fast.”

“I was then at the age when one accepts practically nothing unquestioned, and so I started to reflect on just how fast an ‘immeasurably fast’ reaction might be,” Dr. Eigen recalled in his Nobel lecture.