Chapter Ii. 20

Cosmo, Grand Duke of Tuscany, invites Galileo to Pisa--Galileo visits Venice in 1609, where he first hears of the Telescope--He invents and constructs one, which excites a great sensation--Discovers Mountains in the Moon, and Forty Stars in the Pleiades--Discovers Jupiter's Satellites in 1610--Effect of this discovery on Kepler--Manner in which these discoveries were received--Galileo appointed Mathematician to Cosmo--Mayer claims the discovery of the Satellites of Jupiter--Harriot observes them in England in October 1610,