空者控也 Empty Means Gone
內中有一個勉強的小妖，把瓶提上來道：「你看這不輕了？」老魔揭蓋看時，只見裡面透亮，忍不住失聲叫道：「這瓶裡空者控也。」内中有一个勉强的小妖，把瓶提上来道：「你看这不轻了？」老魔揭盖看时，只见里面透亮，忍不住失声叫道：「这瓶里空者控也。」
逐句解 Line by line
One rather forward lesser fiend among them hauled the bottle right up and said, "Look at that — isn't it light?"
勉強 is miǎn qiǎng, and the sense here is someone pushing himself forward a little beyond his station. He is the junior who contradicts the boss by demonstration rather than argument, and he lifts a thirty-six-man object with one hand to do it.
The old fiend lifted the lid to look, and saw the light coming through inside. He could not help crying out, "This bottle is empty — kōng means cleaned out!"
空者控也 is a scholar's formula — X means Y — of the kind used to gloss a classic, and the demon uses it to announce that his jar is empty. 控 means to drain or tip out. He is so rattled that he explains his own exclamation.
The book has been characterising these demons as an institution for two chapters and this is the punchline. Faced with a catastrophe, the chief reaches for the register of a commentary on the classics. It is exactly the reflex of a man who has spent centuries acquiring dignity.
The little demon who lifts the bottle deserves his moment too. He is the only creature in the chapter who resolves a dispute by picking something up, and the novel rewards him with an adjective and then never mentions him again.