The two men apparently recognised each other at once.  So we have it from the detective.  There was sincerity in the delight of their hand-clasp.  A strange pair, both of them with the distinction and poise that come from refinement and intellectual training; though in physique they were almost opposite, there was still a strange, almost mutual, bond between them.  Dr. Holcomb was beaming.

“At last!” he greeted.  “At last!  I was sure we could not fail.  This, my dear Dr. Avec, is the greatest day since Columbus.”

The other took the hand.

“So this is the great Dr. Holcomb.  Yes, indeed, it is a great day; though I know nothing about your Columbus.  So far it has been simply wonderful.  I can scarcely credit my senses.  So near and yet so far.  How can it be?  A dream?  Are you sure, Dr. Holcomb?”

“My dear Rhamda, I am sure that I am the happiest man that ever lived.  It is the culmination.  I was certain we could not fail; though, of course, to me also it is an almost impossible climax of fact.  I should never have succeeded without your assistance.”

The other smiled.

“That was of small account, my dear doctor.  To yourself must go the credit; to me the pleasure.  Take your sun, for instance, I—­ but I have not the language to tell you.”

But the doctor had gone in to abstraction.

“A great day,” he was beaming.  “A great day!  What will the world say?  It is proved.”  Then suddenly:  “You have eaten?”

“Not yet.  You must allow me a bit of time.  I thought of it; but I had not quite the courage to venture.”

“Then we shall eat,” said the other man.  “Afterward we shall go up to the lecture-room.  Today I shall deliver my lecture on the Blind Spot.  And when I am through you shall deliver the words that will astonish the world.”

But here it seems there was a hitch.  The other shook his head kindly.  It was evident that while the doctor was the leader, the other was a co-worker who must be considered.

“I am afraid, professor, that you have promised a bit too much.  I am not entirely free yet, you know.  Two hours is the most that I can give you; and not entirely that.  There are some details that may not be neglected.  It is a far venture and now that we have succeeded this far there is surely no reason why we cannot go on.  However, it is necessary that I return to the house on Chatterton Place.  I have but slightly over an hour left.”

The doctor was plainly disappointed.

“But the lecture?”

“It means my life, professor, and the subsequent success of our experiment.  A few details, a few minutes.  Perhaps if we hurry we can get back in time.”

The doctor glanced at his watch.  “Twenty minutes for the train, twenty minutes for the boat, ten minutes; that’s an hour, two hours.  These details?  Have you any idea how long, Rhamda?”

“Perhaps not more than fifteen minutes.”