Project Gutenberg #27378
The Story of the Heavens
Robert S. Ball
1885Ball's illustrated popular survey of astronomy, prepared chapter by chapter from Project Gutenberg HTML.
Project Gutenberg #27378 Public domain in the United States Cover source Local typographic cover created for MojiMori from public-domain source metadata
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to weigh Mercury in the celestial balance, and determine his mass in comparison with the other globes of our system. This is a delicate operation, but it leads us through some of the most interesting paths of astronomical discovery. The weight of the planet, as recently determined by Von Asten, is about one twenty-fourth part of the weight of the earth, but the result is more uncertain than the determinations of the mass of any of the other larger planets.
[Pg 167]