Emotion seemed to fuel plenty of sighs by Humphrey Bogart's character Rick (right) in the 1942 film classic Casablanca, and even Rick's good friend Sam, played by actor Dooley Wilson, couldn't console him.
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Alchemist Hennig Brand looks focused, if maybe a bit drained, in this 1795 painting by Joseph Wright. The painting depicts Brand's discovery of the chemical element phosphorus.
Joseph Wright of Derby/Wikimedia