[ 5 6 4 ] 
tainty, without any regard to the diftance of the 
object. 
Upon the whole, it may be concluded, that this 
micrometer is a complete inflrument in its kind ; 
having many advantages above the common fort, 
without any of their diladvantages : And there is no 
doubt, but, when brought into practice, it will tend 
much to the advancement of aftronomy. 
LXX V. An Account of an Earthquake felt at 
York on the 19 th of April 1754. In a 
Letter from Mr. David Erfkine Baker to 
Tho. Birch, D. D. Secret. R . S. 
Read Apr. 25 
* 754 - 
O 
Dear Sir , 
N Friday night laft, the 19th in* 
ftant, at about eleven o’clock, we 
were alarm’d, in this city, with the fhockof an earth- 
quake. As I was myfelf in London, and felt both 
the lliocks, which happen’d there in the year 1770, I 
became immediately lenfible of what it was. In the 
room, in which I was fitting, which was on a firft floor, 
the tremulous, or rather undulating, motion of the floor 
was very plain ; and the windows rattled, as if they 
had been fhaken by a fudden fquall of wind. The 
fhock lafted for about three feconds, and was at- 
tended, or rather preceded, by a rumbling noife, not 
much unlike that made by an empty hearfe driven 
over a hone pavement, and, indeed, exactly the fame 
with that, which I remember to have heard, with both 
the (hocks, in London, in 1750. The violence of the 
(hock 
