He was fairly drunk, and feeling melancholy about all the sinking he had done in the world. Throughout the rough years the Greek alphabet had leaked out of his mind a letter at a time-in fact, the candle of knowledge he had set out with had burned down to a sorry stub.
The character reflects on his state of mind, feeling quite inebriated and weighed down by a sense of sadness regarding his past experiences and failures. The imagery of "sinking" suggests deep emotional turmoil, as he struggles with the consequences of his actions and the burden of lost opportunities.
As time has passed, he has been unable to retain the knowledge and wisdom he once possessed, symbolized by the Greek alphabet slipping...