<Notes> Bartholin and Birefringence

Abstract

In 1669, Erasmus Bartholin reported birefringence, a new optical phenomenon which was different from all the others known at that time. Although his Experimenta crystalli islandici disdiaclastici generally has been mentioned merely as a report of a puzzling phenomenon that had to wait until the nineteenth century for explanation, his treatise itself offers insights that are significant in the history of optics. By analyzing these insights, this paper will shed light on some aspects of optical studies in the 17th century