According to Wikipedia, optical activity was first observed in 1811 in quartz. Louis Pasteur's contribution is also mentioned there and in other sources as a major advancement in establishing optical activity as a distinct characteristic of a compound, specifically as a differentiating factor between two enantiomers - a difference that became a standard descriptive characteristic.
My question is how did they even think of that? Why would Pasteur, Arago, Herschel, and other chemists would think of testing the effect of polarized light on chemical compounds? (vice versa actually, chemical compounds affect polarized light, but I assume they did not know that prior to that discovery...). Was it a standard lab procedure at the time?
Testing and determining physical characteristics (such as melting point, boiling point, etc.) seem reasonable and pretty straightforward, but I am wondering how did polarized light entered the chemistry lab as an identifying procedure.