838 THE POPULAR SCIENCE MONTHLY. 



Soon after entering upon his professorship, in 1740, Winthrop 

 observed a transit of Mercury over the sun, and sent a report of 

 his observations to the Royal Society. This paper was printed in 

 the society's Transactions, and was favorably mentioned in the 

 Memoirs of the French Academy. Prof. Winthrop was thanked 

 by the society, and was asked to continue his communications. 

 Winthrop was now launched upon a long and useful career, dur- 

 ing which he was held in high esteem as a teacher of science at 

 home, while his investigations won him much credit abroad. 

 There is sufficient evidence as to his success as an instructor to 

 justify the words of President Quincy, who, in his History of 

 Harvard University, says of Winthrop : " The zeal, activity, and 

 talent with which he applied himself to the advancement of these 

 sciences [i. e., physics and astronomy] justified the expectations 

 which his early promise had raised. As a lecturer he was skillful 

 and attractive, and during forty years he fulfilled the duties of 

 the professor's chair to universal acceptance." Many of his pa- 

 pers on astronomical subjects are to be found in the volumes 

 issued by the Royal Society during his lifetime, among these be- 

 ing an essay on comets, in Latin, entitled Cogitate de Cometis, 

 which he transmitted to the society in 17G5, on the occasion of 

 his becoming a member of that body. 



On November 18, 1755, an earthquake occurred which terrified 

 the superstitious people of all New England, who regarded it as 

 a direct expression of the wrath of God. To calm the popular 

 terror, Prof. Winthrop read a public lecture on the earthquake in 

 the college chapel. He accounted for such disturbances as being 

 produced by the expansive action of heat upon vapors contained 

 in underground cavities, and argued ably in support of this 

 theory. He also stated that earthquakes had occurred at inter- 

 vals in New England from the time the first settlers landed, but 

 that not a single life had ever been lost, nor had any great dam- 

 age ever been done by them. In conclusion, he maintained that 

 earthquakes are " neither objections against the order of Provi- 

 dence nor tokens of God's displeasure, according to the views of 

 skeptical or superstitious minds, but that they are the neces- 

 sary consequences of general laws." This lecture was published 

 by request of the college authorities, and an account of the earth- 

 quake which Winthrop sent to the Royal Society was also 

 printed. 



At that time lightning-rods had been invented about three 

 years, and a Boston minister published an essay in which he sug- 

 gested that the use of Franklin's " iron points " might have caused 

 the earthquake by drawing the electric fluid from the clouds and 

 concentrating it on that part of the earth. This led Prof. Win- 

 throp to add an appendix to his lecture in which he defends the 



