Chaim Weizmann (1874-1952) was the first president of Israel, and also a chemist who published many articles and filed dozens of patents. His discovery of a method for producing acetone from corn using microorganisms is his most well-known achievement due to its contribution to the British military effort in World War I.

During the 1920s Weizmann devoted all of his efforts to Zionist political activity, resigning his scientific work. For over a decade he did not write a scientific article nor did he file a new patent. Only in the 1930s did Weizmann return to work as a chemist. In 1931 he founded a scientific laboratory in London (which was later destroyed in a German bombing), and from 1934 he divided his time between his London lab and the Ziv Institute in the Land of Israel (world-famous today as The Weizmann Institute for Science).

The scientific activity of young Chaim Weizmann, culminating in the discovery of industrial production of acetone, has been studied by historians and historians of science. However, no historical research has been done thus far on Weizmann’s scientific career from the 1930s and beyond. A situation in which a scientist disconnects from scientific endeavor and returns to it years later, when that scientific field has evolved and changed, is rare and raises a number of questions.

In our talk we will discuss the obstacles Weizmann encountered upon his return to chemistry and how he managed to reintegrate, scientifically and socially, into the researchers’ community. We will examine to what extent his studies in the later period can be seen as a continuation of studies done in the earlier period, and to what extent they reflect a change in direction. By focusing on the less familiar years of Weizmann’s scientific activity, we hope to flesh out a more complete picture of his work in chemistry and biochemistry. Moreover, in the broader sense this spotlight may help us illuminate other issues relating to the pursuit of a scientific career in chemistry during a fascinating and turbulent historical period - the first half of the twentieth century.