PHYSICAL AND MATHEMATICAL SCIENCES.
Galileo ’s observations on the moon gave additionalsupport to the solar system, from the entire confirmationthey afforded to the effects of reflected light seen inthe lights and shadows on the moon’s surface. TheAristotelians had determined that the moon was a per-fect body. Hence they loathed the doctrines of Galileo ,who took delight, they said, in distorting and ruiningthe fairest works of nature. Lodovico delle Colombe endeavoured to reconcile the contending parties, by sug-gesting that the apparently hollow parts were filled upwith a pure transparent crystalline medium.
The appearance of a slight illumination in the darkpart of the new moon (commonly called the old moonin the new moon’s lap), was explained by Galileo , as ithad been by Leonardo da Vinci and Msestlin, to arisefrom “ earth-shine.” This was another source of offenceto the Aristotelians, who could not condescend to admitthat the earth could shine like a planet. Examining thefixed stars, he was at first disappointed at finding noincrease in their sensible magnitudes ; but was equallyastonished at the vast multiplication of their numbers.Directing his telescope to the milky way, he discovered.its real nature, as consisting of a multitude of smallstars : and extended the same conclusion to other nebula'.
The planet Saturn next engaged his attention : andhe describes in detail the perplexities in which he wasinvolved from the apparently anomalous figure of theplanet; sometimes single, sometimes with a body cm.each side, or triple. He recorded this observation inan anagram, as also he did another telescopic discovery,the phases of Venus . This was one of the most decidedproofs of the Copernican system, and a fulfilment ofCopernicus ’s prediction. * The supposed absence ofsuch phases had been urged by a distinguished Aris-totelian as a proof of the old system. Galileo alsonoticed the less conspicuous changes of phase in Mars .
On receiving the appointment from the grand dukeCosmo, he resigned liis chair at Padua ; which occa-
* See p. ISfi.