NOTES 79 



a strong supporter of Charles I. He was impeached by the Long Parlia- 

 ment, and beheaded in 1645. 



15 19 Copernican hypothesis: Nicholas Copernicus (1473-1543) was a 

 noted Polish and German astronomer. Among his conclusions were : 

 That the moon alone revolves about the earth ; the earth is a planet 

 whose orbit lies between Venus and Mars ; the planets revolve about the 

 sun ; and the apparent revolution of the heavens is due to the rotation of 

 the earth on its axis. (Students may find interest in studying about 

 Aristarchus, the Greek philosopher, 250 B.C.) 



15 22 selenography : science that treats of the physical conditions of 

 the moon ; akin to physical geography. 



15 25 Torricellian experiment : the discovery by the Italian physicist, 

 Evangelista Torricelli (1608-1647) of the principle of the barometer. 



15 31 Galileo (1564-1642) : Italian astronomer ; constructed a 

 thermometer and a telescope ; defended the Copernican theory (see note 

 on 1. 19 above), and was compelled by the Inquisition to renounce these 

 views. 



15 31 Sir Francis Bacon (1561-1626) : English statesman and phi- 

 losopher ; founder of the modern inductive philosophy. Bacon's great 

 philosophical work, " Instauratio Magna " (" Great Restoration of the 

 Sciences "), was written in Latin ; and the best known part, " Novum 

 Organum " (" New Method ") was published in 1620. Sir John Herschel, 

 the eminent astronomer, wrote as follows of Bacon and his work : " By 

 the discoveries of Copernicus, Kepler, and Galileo, the errors of the Aris- 

 totelian philosophy were effectually overturned on a plain appeal to the 

 facts of nature ; but it remained to show; on broad and general princi- 

 ples, how and why Aristotle was in the wrong ; to set in evidence the 

 peculiar weakness of his method of philosophizing, and to substitute in 

 its place a stronger and better. This important task was executed by 

 Francis Bacon, Lord Verulam, who will therefore justly be looked upon 

 in all future ages as the great reformer of philosophy." 



17 1 Sir Isaac Newton (1642-1721) : English philosopher ; established 

 the law of universal gravitation. Newton has been called the most 

 remarkable mathematician and natural philosopher of his own or perhaps 

 any other age. His work upon reflecting telescopes led in 1671 to his 

 election to the Royal Society. Urged on by the scientist Halley (of 

 comet fame) he produced a treatise embodying his results upon gravita- 

 tion. This was the famous Principia (Philosophiae Naturalis Principia 

 Mathematical) "The Mathematical Principles of Natural Philosophy." 

 It was accepted by the Royal Society in 1686, and published in the 

 summer of the following year. 



