348 PHILOSOPHICAL TRANSACTIONS. [aNNO i72Q. 



An Account of an Earthquake at Boston in New England. Bij the Rev. 

 Be7ijami7i Colman. N" 409, p. 124. 



This earthquake came suddenly on in the night of Oct. 29, 1727, between 

 ]0 and II, in a very still and fair evening: and the tremblings and rumblings 

 have returned often for some months since the great shake, and at times for 

 9 months after it. 



The town of Newbury, at the mouth of Merrimack river, about 40 miles 

 north east from Boston, is the place that seems to have been the centre of the 

 shock and shakes felt by us. There the earth opened, and threw up many 

 cart-loads of a fine sand and ashes, mixed with some small remains of 

 sulphur. The family nearest to this eruption, it being in that part of the town 

 where the houses lie at a distance from each other, were in the terrors of 

 death; the roar and shock being much more particularly terrible on them. 

 And yet upon us at 4 miles distance, and upon others at double that distance, 

 it was very terrifying and astonishing. 



Five or seven small shakes were felt by us, after the first and great one, that 

 night and in the morning following; but these and other following rumbles 

 and tremblings, were louder and greater at Newbury and the adjacent places, 

 than with us; and they felt and heard many times when our parts did not; but 

 yet from week to week, we and the places about us felt and heard some of the 

 greater tremors, both by day and night, and in all varieties of weather. 



As to any alterations in the air or water after a shock, Mr. C. could never 

 discern any thing; particularly as to the wind being raised after a shock, when 

 it was calm before, which some reported, he could never perceive the least 

 difference. 



A Proposition on the Balance, not noticed by Mechanical Writers, explained 

 and confirmed by an Experiment before the Royal Society. By J. T. Desa- 

 guliers, LL. D. F.R.S. N°409, p. 128. 



Theorem. — ab, fig. 3, pi. 8, is a balance, on which is supposed to hang at 

 one end b the scale e with a man in it, who is counterpoised by the weight 

 w hanging at a, the other end of the balance. That if such a man, with a 

 cane or any rigid straight body, pushes upwards against the beam any where 

 between the points c and b, he will thereby make himself heavier, or over- 

 poise the weight w, though the stop gg hinders the scale e from being thrust 

 outwards from c. Also, if the scale and man should hang from d, the man 



