558 



Our Surroundings 



gravitation. You recall how his observation of an apple falling 

 to the earth from a tree caused him to connect the force that 

 attracts all objects toward the center of the earth with the force 

 which keeps the planets in their orbits. This was set forth in 

 his treatise known as the Principia. 



Newton formulated three 

 statements now accepted by 

 scientists as the laws of mo- 

 tion : First, every body con- 

 tinues in a state of rest or of 

 uniform motion in a straight 

 line unless impelled by ex- 

 ternal force to change that 

 state; second, the rate of 

 change of momentum is pro- 

 portional to the force acting, 

 and takes place in the direc- 

 tion in which the force acts; 

 and third, to every action 

 there is an equal and opposite 

 reaction. 



Newton received many 

 honors, among which was 

 election as a member of 

 the Royal Society of Lon- 

 don. He died in 1727 and was buried in Westminster Abbey. 



Watt. James Watt was born in Greenock, Scotland, in 1736. 

 As a boy he gave evidence of ability and at the age of fourteen 

 constructed an electrical machine. He learned the trade of mak- 

 ing mathematical instruments and became so proficient that he 

 was appointed instrument maker to the University of Glasgow. 

 Later he became distinguished for improvements in connection 

 with the Newcomen engine, a machine used in pumping water 

 from mines by means of steam power, invented by a blacksmith 

 named Thomas Newcomen. His inventions so improved this 

 machine that it generated much greater power with the use of less 

 fuel. By the employment of a connecting rod and crank shaft he 



Brown Brothers. 



SIR ISAAC NEWTON 



The Discoverer of the Law of .Gravitation. 



