So that accounted for the grumbling and cursing I had heard upon the march through the forest—the warriors had been getting in each other's way because they couldn't see one another any more than I could see them.

"You have certainly achieved invisibility," I said, "or are you hatched invisible from invisible eggs?"

"No," he replied, "we are quite normal people; but we have learned to make ourselves invisible."

Just then I saw an open courtyard ahead of us, and as the warriors passed out of the lighted corridor into it they disappeared. When Kandus and I stepped out, I was walking alone again. It was most uncanny.

The city was spotted with these courtyards which gave ventilation to the city which was, otherwise, entirely roofed and artificially lighted by the amazing lights which gave complete visibility to its inhabitants. In every courtyard grew spreading trees, and upon the city's roof vines had been trained to grow; so that, built as it was in the center of the Forest of Lost Men, it was almost as invisible from either the ground or the air as were its people themselves.

Finally we halted in a large courtyard in which were many trees wherein iron rings were set with chains attached to them, and here invisible hands snapped around one of my ankles a shakle that was fastened to the end of one of these chains.

Presently a voice whispered in my ear, "I will try to help you, for I have rather taken a liking to you—you've got to admire a man who can jump thirty feet into the air; and you've got to be interested in a man who says he comes from another world forty-three million miles from Barsoom."

It was Kandus. I felt that I was fortunate in having even the suggestion of a friend here, but I wondered what good it would do me. After all, Kandus was not the jeddak; and my fate would probably rest in the hands of Ptantus.

I could hear voices crossing and recrossing the courtyard. I could see people come down the corridors or streets and then fade into nothingness as they stepped out into the courtyard. I could see the backs of men and women appear quite as suddenly in the entrances to the streets as they left the courtyard. On several occasions voices stopped beside my tree and discussed me. They commented upon my light skin and gray eyes. One voice mentioned the great leap into the air that one of my captors had recounted to its owner.

Once a delicate perfume stopped near me, and a sweet voice said, "The poor man, and he is so handsome!"

"Don't be a fool, Rojas," growled a masculine voice. "He is an enemy, and anyway he's not very good-looking."

"I think he is very good-looking," insisted the sweet voice, and how do you know he's an enemy?"