Science Buddies: "Ask an Expert"

Hello,

Do you know when John Joly invented the photometer? I've been trying to find it but can't.

Thanks

I've tried looking for a while too, and all the articles I've found only list the dates for his awards and a few other discoveries. Do you absolutely need the date in your paper? You could mention when he was born and died to give a range, or you could give a date for some of his awards.

I would also try looking up "photometer" in a real encyclopedia.