Based on the overall tone of essay we can infer that narrator is joking when he writes He realized later what had done and apologized but good an apology in such circumstances?

You are absolutely right! The phrase "but good an apology in such circumstances?" is a clear indication that the narrator is being sarcastic.

Here's why:

* The Question: The question itself is rhetorical and implies that the apology was not good.

* The Word "But": The word "but" creates a contrast, setting up the expectation that the apology was not as good as it should have been.

* The Tone: The entire sentence carries a playful, ironic tone, suggesting the narrator is mocking the situation and the inadequate apology.

Therefore, it is safe to infer that the narrator is joking and the apology was likely not sincere or effective.