90 MEMOIR OF GALILEO. 



escope, astonished the whole scientific world. The ideas, 

 however, which Galileo enunciated in his " Sidereal Mes- 

 senger/' were attacked on all hands by the Aristotelians. 

 They even denied the existence of the four satellites which 

 Galileo had discovered : some affirming he was deceived by 

 reflected rays ; and others, that it was a ruse to afford him- 

 self a subject for discussion. Their existence having been 

 at last indisputably established, others began to claim the 

 priority of discovery, and to pretend that they had dis- 

 covered additional satellites of Jupiter. Some gave this 

 planet as many as twelve moons ; but they were gradually 

 found out to be fixed stars, and Galileo remained the ori- 

 ginal discoverer of the four secondary planets. 



Before the close of 1610, Galileo discovered Saturn's ring, 

 although not conscious of its true nature, or the appear- 

 ance which it presents when highly magnified. He de- 

 scribed Saturn as a triple star, each retaining its relative 

 position. Shortly after, he discovered that Yenus presented 

 phases like the moon, when at different parts of her orbit. 

 He likewise discovered spots on the sun's surface, from which 

 he calculated that that luminary had a motion on its axis, 

 completed in about twenty-eight days. In 1612, he pub- 

 lished a treatise on floating bodies, displaying a knowledge 

 of many true principles in hydrostatics. It was violently 

 attacked j but the master mind of Galileo refuted his oppo- 

 nents as soon almost as they appeared. 



The great objection raised by the priesthood and follow- 

 ers of Aristotle, against the doctrines advanced by Galileo, 

 was, that they were contrary to Scripture, and ran coun- 

 ter to the doctrine of the Church. In refuting these and 

 other objections, Galileo added to the calm arguments of 

 reason the bitterness of sarcasm. In 1613 he published a 

 letter to prove that the Scriptures were not to be taken as 

 guides in philosophy, and that the language found in the 

 Bible was wrongly interpreted, and might with equal pro- 



