When I wrote about Claude Debussy’s burn on overworked musical pieces, “They smell of the lamp, not of the sun,” I didn’t realize that he was quoting a very old idiom. From a 1898 Dictionary of Phrase and Fable: 

Smells of the lamp
Said of a literary production manifestly laboured. Plutarch attributes the phrase to Pytheas the orator, who said, “The orations of Demosthenes smell of the lamp,” alluding to the current tale that the great orator lived in an underground cave lighted by a lamp, that he might have no distraction to his severe study.

In Lives, Plutarch writes about how Demosthenes wasn’t necessarily quick on his feet with speeches — if he was asked a question in public, he wouldn’t stand up and talk about something he hadn’t thought about, but took time to go away to his study and work out arguments. 

For this, many of the popular leaders used to rail at him, and Pytheas, in particular, once told him scoffingly that his arguments smelt of lamp-wicks. To him, then, Demosthenes made a sharp answer. “Indeed,” said he, “thy lamp and mine, O Pytheas, are not privy to the same pursuits.”

In another translation: 

…many of the popular pleaders used to make it a jest against him; and Pytheas once, scoffing at him, said that his arguments smelt of the lamp. To which Demosthenes gave the sharp answer, “It is true, indeed, Pytheas, that your lamp and mine are not conscious of the same things.”

And another story about his lamp:

And to the thief nicknamed Brazen, who attempted to make fun of him for his late hours and his writing at night, “I know,” he said, “that I annoy you with my lighted lamp. But you, men of Athens, must not wonder at the thefts that are committed, when we have thieves of brass, but house-walls of clay.”

Now I am conflicted, as a burn that is about overworked creative efforts was originally pointed at a dude who was probably just introverted and studious and thoughtful and against bullshittery!

(Always learning.)