126 THE HISTORY OF SCIENCE 



cism. In medicine he invented bifocal lenses and 

 founded the first American public hospital ; in navi- 

 gation he studied the Gulf Stream and waterspouts, 

 and suggested the use of oil in storms and the con- 

 struction of ships with water-tight compartments; 

 in agriculture he experimented with plaster of Paris 

 as a fertilizer and introduced in America the use of 

 rhubarb ; in chemistry he aided Priestley's experi- 

 ments by information in reference to marsh gas. He 

 foresaw the employment of air craft in war. Think- 

 ing the English slow to take up the interest in bal- 

 loons, he wrote that we should not suffer pride to 

 prevent our progress in science. Pride that dines on 

 vanity sups on contempt, as Poor Richard says. 

 When it was mentioned in his presence that birds 

 fly in inclined planes, he launched a half sheet of 

 paper to indicate that his previous observations had 

 prepared his mind to respond readily to the discov- 

 ery. His quickness and versatility made him sought 

 after by the best intellects of Europe. 



I pass over his analysis of mesmerism, his con- 

 ception of light as dependent (like lightning) on a 

 subtle fluid, his experiments with colored cloths, his 

 view of the nature of epidemic colds, interest in in- 

 oculation for smallpox, in ventilation, vegetarianism, 

 a stove to consume its own smoke, the steamboat, 

 and his own inventions (clock, harmonica, etc.), for 

 which he refused to take out patents. 



However, from the many examples of his scien- 

 tific acumen I select one more. As early as 1747 he 

 had been interested in geology and had seen speci- 

 mens of the fossil remains of marine shells from the 

 strata of the highest parts of the Alleghany Moun- 



