[ « ] 
V. An Account of an Earthquake felt at 
Lifbon, December 26, 1764 : In a Let- 
ter to the Rev, Samuel Chandler, D, D. 
F, R. S, 
Read Jan. 3T, YTTEdnefclay December 26, 1764, I 
*' 5 - VV was awakened about 3 o’clock in 
the morning by violent fqualls of wind, and a deluge 
of rain, accompanied with almoft uninterrupted 
fiafhes of lightning, many of which ended in a 
bright purple. About 8, we had fome didant claps 
of thunder; at 10, fome more. Before ii,the rain 
ceafed, and the fun fhone forth. In Jefs than half 
an hour after, we had a fudden diock, preceded by a 
rumbling noife, and fucceeded by a dead cairn of at 
lead half an hour. Mod of them here maintain, 
that it was the fevered diock they have felt ; but as 
it laded no longer than you could clap your hands 
twice, it did little or no damage. They unani- 
moufly declare however, that they never had any 
thing of the fame kind, this being a fudden perpen- 
dicular heaving up ; whereas all their former diocks 
were iindulatory. As it is the only one I have felt, 
I can give no decidon ; and I dare fay you will be- 
lieve my curiodty will be fatisfied without a fecond 
to compare with it. I had folly enough, in the 
mean time, to invent a method for meafuring the 
drength and diredion of future diocks. Lad night, 
they fay, we had a gentle diock about 12 o’clock. 
G 2 Thank 
