The Doctor then took him through the letter, and invited him to throw light upon it. He was chiefly interested in the part about revenge, and he forced Tudor to explain that the revenge was because Dr. Dunston had taken away his glazier's diamond. Dr. Dunston then said that incident was long ago closed, and that, in fact, after the pane of glass in his study had been taken out and a new one put in, he had dismissed the matter from his mind. He seemed much surprised that Tudor had not dismissed the matter from his mind also, and he told him that the revengeful spirit always came to grief in the long run. He then wound up by saying:
"You sign yourself 'The Unknown,' wretched boy, but let this be a lesson to you that henceforth you are neither unknown to your head master or your God. For the rest, since you have the grace, in this penitential though patronizing communication, to express sincere regret at your conduct, and also to record the fact that you are my 'Well-wisher,' though that is not at all the sort of expression suitable from a Fourth Form scholar to his head master--since, I say, I find these signs of grace, I shall not inflict the extreme penalty on this occasion. For the moment I have not determined on my next step, and will thank you to wait upon me this time to-morrow. Now you may go."
And Tudor said:
"Thank you very much, sir," and went.
He was a great deal cast down, and admitted, for once, I was right. But though his feeling for the Doctor was now, on the whole, one of patience and thankfulness, his feeling for Brown was very different, and when the wretched Brown grinned at Tudor, and rotted him in class, and told the whole story of how he had played the beastly sleuth-hound on Tudor, and started calling him "The Unknown," Tudor took it with dignified silence, and from that instant started to plan the greatest revenge of his life. He told me that it might not be at Merivale he would be revenged, but in the world at large, and if it was not until Brown had grown old and bald-headed, the end was bound to be just the same, and the rest of Brown's life, however long it might last, would undoubtedly be ruined by Tudor. And he also said that he was jolly glad the missionary feeling had left him, so that not a shadow of remorse might come between him and Brown when "The Day" arrived.
Well, there was only one thing more rather interesting about Tudor's revenge on the Doctor, and that was Dr. Dunston's revenge on Tudor. Tudor went to him again at the appointed time, and, after a lot of jaw, the Doctor told Tudor that he must now write out the complete article on "Optics," in the Encyclopædia Britannica, including all the algebra and everything. There were exactly ten huge pages of this deadly stuff, and Tudor was fairly frantic at first; but curious to relate, after he had done one page, he found it quite interesting in its way. Then it got more and more interesting, as it went on, and Tudor finally decided that there was no doubt, with his strong feeling for the science of optics, that he ought to take it up as a profession.
I asked him if he should take up microscopes or telescopes, and he said telescopes certainly, because that meant astronomy, and in time you might rise to be Astronomer Royal of Greenwich, which was something.
I said:
"It is a great thing to know the stars and comets by their names."
And he said: