Met een knalgaslantaarn in een biljartzaal

With an oxyhydrogen lantern in a billiard room. The illustrated lectures of Ernst Cohen

The Utrecht University professor of Chemistry, Ernst Cohen (1869-1944) gave lectures illustrated with an optical lantern between at least 1899 and 1938. His presentations addressed different audiences, from colleagues at chemical conventions to members of societal and professional associations and audiences at adult education centres. The range of topics he covered was equally broad: from lectures on the use of photography in the sciences to chemical issues and entertaining presentations on caricature and the natural sciences. Cohen used the projected image for a variety of purposes that were linked to his outreach activities as an academic who wanted to address audiences both inside and outside academia. This contribution retraces Cohen’s activities as a lecturer using the lantern to reach diverse audiences and discusses the topics that he chose for his illustrated lectures.