It has, on more than one occasion, been asserted by observers that a spot has been seen traversing the sun, and from its shape and general appearance they have presumed it to have been an Intra-Mercurial planet.
"The Story of the Heavens"
Robert Stawell Ball
Among them Professor Watson saw an object which to him seemed to be the long-sought Intra-Mercurial planet.
"The Story of the Heavens"
Robert Stawell Ball
The Intra-ship communicators blared, "All passengers and personnel strap in.
"Man of Many Minds"
E. Everett Evans