A melancholy-looking man, he had the appearance of one who has searched for the leak in life's gas-pipe with a lighted candle.

Wodehouse’s simile turns a familiar image of gloom into a comic miniature narrative: the man looks as if he has done something catastrophically foolish—searching for a gas leak with a lit candle—inviting an explosion. The humor comes from the disproportionate specificity and the implied backstory of self-inflicted disaster. It also exemplifies Wodehouse’s style of character-sketching through absurdly precise comparisons, where emotional states (melancholy, defeat, anxiety) are rendered as physical “evidence” of misadventure. The line suggests not merely sadness but the drained, chastened look of someone who has learned—painfully—that the world punishes incompetence and bad judgment.