Laudator Temporis Acti

Tony Augarde, The Oxford Guide to Word Games (1984; rpt. Oxford: Oxford University Press, 1986), p. 196:

Hannah More, in a letter to her sister on 17 February 1786, wrote:

Mrs Fielding and I, like pretty little Misses, diverted ourselves with teaching Sir Joshua and Lord Palmerston the play of twenty questions, and thoroughly did we puzzle them by picking out little obscure insignificant things which we collected from ancient history. Lord North overhearing us, desired to be initiated into this mysterious game, and it was proposed that I should question him: I did so, but his twenty questions were exhausted before he came near the truth. As he at length gave up the point, I told him my thought was the earthen lamp of Epictetus. 'I am quite provoked at my own stupidity,' said his lordship, 'for I quoted that very lamp last night in the House of Commons.' (The Letters of Hannah More, ed. R. Brimley Johnson, 1926).

Epictetus tells the story in his Discourses (tr. W.A. Oldfather).

1.18.15-16:

Something similar happened to me also the other day. I keep an iron lamp by the side of my household gods, and, on hearing a noise at the window, I ran down. I found that the lamp had been stolen. I reflected that the man who stole it was moved by no unreasonable motive. What then? To morrow, I say, you will find one of earthenware.

1.29.21:

That is why I lost my lamp, because in the matter of keeping awake the thief was better than I was. However, he bought a lamp for a very high price; for a lamp he became a thief, for a lamp he became faithless, for a lamp he became beast-like. This seemed to him to be profitable!

See also Lucian, The Ignorant Book Collector 13 (tr. H.W. Fowler and F.G. Fowler):

But there: what need to go back to Orpheus and Neanthus? We have instances in our own days: I believe the man is still alive who paid 120 pounds [3000 drachmas] for the earthenware lamp of Epictetus the Stoic. I suppose he thought he had only to read by the light of that lamp, and the wisdom of Epictetus would be communicated to him in his dreams, and he himself assume the likeness of that venerable sage.