Percival Lowell

Astronomer Percival Lowell (1855-1916) was the leader of the 1893 expedition to Mars, and the brain behind its inception. He was, in Lt. Dibbs' words, "a fine commander," until he used the dream machine found at Elysium and had his body taken over by Tekapesh. Prior to this, he had been communicating with Earth using the lens towers to transmit Morse code, and was keeping the construction of a new space cannon on schedule.

When the Avatar discovered Lowell in Martian Dreams, he was still trapped in the Dream-World, attempting to discover the ninth planet of the Terran Solar System. The Avatar was able to aid with Lowell's in-dream tasks, bringing his mind back into his body once Tekapesh was convinced of another way the trapped Martians could live.

Lowell proved to know a great deal of the lens towers, and how to make use of them to melt the polar caps, thus restoring water to the Martian canals.

Trivia

 * In the real world, it was Percival Lowell who originated the Planet X theory.