Finally, that the Rhamdas were perfectly willing for the coming contest to take place, on the evening of the Day of the Prophet, in the Temple of the Bell and Leaf.

“Jan Lucar,” Watson felt prompted to say, “you need have no fear as to the outcome of the ordeal, whatever it may be.  With your faith in me, I cannot fail.  For the present, I need books, papers, scientific data.  Moreover, I want to see the outside of this building.”

The guardsman bowed.  “The data is possible, my lord, but as to leaving the building—­I must consult the queen and the Rhamda Geos first.”

“But I said must” Watson dared to say.  “I must go out into your world, see your cities, your lands, rivers, mountains, before I do aught else.  I must be sure!”

The other bowed again.  He was visibly impressed.

“What you ask, my lord, is full of danger.  You must not be seen in the streets—­yet.  Untold bloodshed would ensue inevitably.  To half the Thomahlians you are sacred, and to the other half an impostor.  I repeat, my lord, that I must see the Geos and the queen.”

Another bow and the Jan disappeared, to return in a few moments with the Geos.

“The Jan has told me, my lord, that you would go out.”

“If possible.  I want to see your world.”

“I think it can be arranged.  Is your lordship ready to go?”

“Presently.”  Watson laid a hand on the big globe he had already puzzled over.  “This represents the Thomahlia?”

“Yes, my lord.”

“How long is your day, Geos?”

“Twenty-four hours,”

“I mean, how many revolutions in one circuit of the sun, in one year-circle?”

As he uttered the question Chick held his breath.  It had suddenly struck him that he had touched an extremely definite point.  The answer might place him!

“You mean, my lord, how long is a circle in term of days?”

“Yes!”

“Three hundred and sixty-five and a fraction, my lord.”

Watson was dumbfounded.  Could there be, in all the universe, another world with precisely the same revolution period?  But he could not afford to show his concern.  He said: 

“Tell me, have you a moon?”

“Yes; it has a cycle of about twenty-eight days.”

Watson drew a deep breath.  Inconceivable though it appeared, he was still on his own earth.  For a moment he pondered, wondering if he had been caught up in tangle of time-displacement.  Could it be that, instead of living in the present, he had somehow become entangled in the past or in the future?

If so—­and by now he was so accustomed to the unusual that he considered this staggering possibility with equanimity—­if the time coefficient was at fault, then how to account for the picture of the professor, in that leaf?  Had they both been the victims of a ghastly cosmic joke?

There was but one way to find out.