In 1705, Edmund Halley discovered that a spectacular comet that had been observed by astronomers since 240 BC was a periodic visitor every 75-76 years. Halley comet would be visible to the naked eye in the northern hemisphere in 1910. An observatory including a telescope was established on Mt. Tamalpais. Professor Ellerman of the Mt. Wilson Solar Observatory and Professor McCade of the U. S. Weather Bureau promised to spend a night there. The Mount Tamalpais Railroad ran special trains to the summit of Ml. Tamalpais on Monday, May 23d, leaving San Francisco at 4:45 p.m., arriving at the summit in time for dinner and to view the sunset. Another train left San Francisco at 6:45 p.m., arriving at the summit shortly after 8 o’clock. From the observatory on Mount Tamalpais one had an unobstructed view of Halley comet during the total eclipse of the moon that took place between 9 and 10 p. m. The summit of Mount Tamalpais being above the fog and the haze that hung over the city provided an excellent view. It was predicted that never again would there be a total eclipse of the moon during a Halley comet visit. Its 1986 visit was called Halley’s comet.