SCIENCE AND REVOLUTION 



observed by Horrox. The barometer was in- 

 vented by Torricelli in 1642. The marquis of 

 Worcester described, in his " Century of Inven- 

 tions," 1663, an apparatus for raising water by 

 the expansive force of steam. Two years later, 

 Isaac Newton published his first improved meth- 

 ods of astronomical calculation. In 1669, Brandt 

 discovered phosphorus. Roemer ascertained the 

 velocity of light in 1675. Leibniz published his 

 invention of the differential calculus in 1684. And 

 in 1687, Newton came forth with his " Principia," 

 enunciating the laws of gravity. Denis Papin, a 

 native of France and professor at the university 

 of Marburg, Germany, conceived the idea, in 

 1688, of obtaining motive power by means of a 

 piston working in a cylinder, through a sudden 

 condensation of steam by cold. In 1698, Captain 

 Savery, an Englishman, obtained a patent for the 

 first actual working steam engine to be used in 

 raising water. And in 1705, Thomas Newcomen, 

 a blacksmith, and John Cawley, a plumber, pat- 

 ented an atmospheric engine, in which condensa- 

 tion was effected by pouring cold water upon the 

 external surface of a cylinder. 



These pioneer efforts in the construction of 

 steam engines were not to be crowned with suc- 

 cess until June 5, 1769, when James Watt ob- 



58 



