ABSTRACT
With social organization came technological change. The inter-war period reshaped techniques and instruments. By the Great War, astronomers were increasingly adopting physical methods of light measurement, and laboratory spectroscopists soon joined them in converting to photographic methods. But engineering practice, wedded to visual methods, remained little changed from the 1860s until the 1920s for the vast majority of photometric work1. Photographic and visual photometrists had distinct outlooks after the war, leading to a divergence of practice between the communities. Only when all practitioners began to employ photoelectric measurement techniques in the early 1930s did practice again coalesce to a single technique.
