SKETCH OF PROFESSOR JOHN WIN THRO P. 839 



discoveries of his friend Franklin, and shows the unreasonable- 

 ness of attributing the earthquake to the action of the rods. He 

 concludes with the hope that he has " fully vindicated the char- 

 acter of those innocent and injured iron points." Some years 

 after, in 1770, he seized another opportunity to defend Franklin's 

 invention, by publishing an essay against the notion that there 

 was great impiety in using lightning-rods, since they prevented 

 the " tokens of Divine displeasure " from " doing their full execu- 

 tion." Under date of October 26, 1770, he writes to Franklin, who 

 was then in London, acknowledging the execution of several com- 

 missions concerning books and instruments, and says in regard to 

 the rods : " I have on all occasions encouraged them in this coun- 

 try, and have the satisfaction to find that it has not been without 

 effect. A little piece I inserted in our newspapers last summer 

 induced the people of Waltham (a town a few miles from hence) 

 to fix rods upon their steeple, which had just before been much 

 shattered and set on fire by lightning." * 



Prof. Winthrop had a clearer understanding of earthquake 

 movements than the generality of scientific men of his time, and 

 was one of the earliest^ if not the first, to apply computation to 

 these phenomena. The chimney of his house was thirty-two feet 

 high, and, observing that bricks were thrown from it so that they 

 fell thirty feet from its foot, he calculated the speed of their 

 motion and found it to be twenty-one feet a second. He perceived 

 also the resemblance between the vibrations of the earth and 

 those of the strings of a musical instrument. 



The fullest published account of the scientific work of Prof. 

 Winthrop is contained in the chapter on Boston and Science, con- 

 tributed to the Memorial History of Boston by Prof. Joseph Lov- 

 ering, who for over fifty years has occupied the same professor- 

 ship that Winthrop held. " Prof. Winthrop was fortunate," says 

 Prof. Lovering, " in living at a time when he could be a witness 

 of three celestial occurrences of transcendent importance to the 

 progress of astronomy namely, the first predicted return of 

 Halley's comet in 1759, after an absence of twenty-seven years, 

 and the transits of Venus across the sun in 1761 and 1769. In 

 1759 the accuracy of astronomical prediction was on its trial, and, 

 months before the time of the expected visit, astronomers were at 

 their posts and looking ; but they were all anticipated by a Saxon 

 peasant who first saw the comet on December 25, 1758. Winthrop 

 saw it on April 3, 1759." He delivered two lectures on comets at 

 this time, which were printed the same year, and reprinted in 

 1811. Prof. Winthrop also observed the comets of 1769 and of 

 1770, "one remarkable for its brilliancy and the other for the dis- 



* Massachusetts Historical Society's Proceedings, vol. xv, p. 13. 



