I did not apprise him of my ability to sense his mental operations, and thus I learned a great deal which proved of immense value to me later and which I would never have known had he suspected my strange power, for the Martians have such perfect control of their mental machinery that they are able to direct their thoughts with absolute precision.

The building in which I found myself contained the machinery which produces that artificial atmosphere which sustains life on Mars. The secret of the entire process hinges on the use of the ninth ray, one of the beautiful scintillations which I had noted emanating from the great stone in my host’s diadem.