144 NATURAL HISTORY AND TOPOGRAPHY OF GROTON, MASS. 



being nearly rectilinear, it must have continued for several hours near 

 the earth, and the universal law of gravity holds equally good, whether 

 bodies are in motion or at rest. 



A Peripatetick. 



It will be noticed that Mr. Winthrop refers to a previous 

 article on the Dark Day, signed " Viator," which also appeared 

 in the Chronicle; and in connection with this reference an 

 extract from a letter on the same subject, written by the 

 Reverend John Eliot, of Boston, to the Reverend Jeremy 

 Belknap, of Dover, New Hampshire, under date of June 3, 

 1780, has some interest. The letter is found in the fourth 

 volume, sixth series, of the Collections of the Massachusetts 

 Historical Society (pp. 191-194). 



Our philosophers this way differ greatly. M r Lathrop * printed 

 an account of the appearance of things, & signed Viator. He was 

 at [Dr. Manasseh] Cutler's, Ipswich Hamlet [Hamilton], with Pro- 

 fessor Sewal & others, who agreed that smoke was the primary cause, 



&c. He is attacked by a Peripatetick, J. VV p., who, thinking 



M r Williams'- was the author, malitiously meanC to lessen his reputa- 

 tion. This gentleman gives without doubt the true cause. The de- 

 tached appearance of the clouds in the forenoon will account for the 

 darkness, as may be illustrated by taking panes of glass & placing 

 them at a small distance from each other. 



Caleb Butler, Esq., in his History of Groton, refers to the 

 same subject, and makes the following explanation of the 

 occurrence : — 



The darkness of this day and of the night following, which was 

 proportionally great, was satisfactorily accounted for, by attentive 

 observers of the phenomenon. There had been, a few days previous, 

 very extensive fires between the settlements in Canada and New 

 England. The state of the atmosphere and currents of the wind had 

 favored the collection and preservation of the smoke over the territory 

 involved in the darkness. The formation of the clouds, too, which 

 prevailed at the time, probably had an agency in producing the result, 

 by being in several layers and holding the smoke between them, and 



1 Reverend John Lathrop, Minister of the Second Church, Boston. 



2 Samuel Williams, Hollis Professor of Mathematics and Natural 

 Philosophy. 



