[ 574 ] 
from the weft, cannot be looked on as any reafonable 
objection to this, but rather the contrary. The ve- 
locity alfo, with which they were all propagated, was 
the fame, being at leaft equal to that of found j for 
they all followed * immediately after the noife that 
preceded them, or rather the noife and the earthquake 
came together : and this velocity agrees very well witli 
the intervals between the time when the firft (hock 
was felt at Lifbon, and the time when it was felt at 
other diftant places, from the comparifon of which, 
it feems to have travelled at the rate of more than 
•f* twenty miles per minute. 
17. An hiftorical account of the earthquakes, which 
have happened in J New England, fays, that, of 
five confiderable ones, three are known to have come 
from the fame point of the com pals, viz. the north- 
weft : it is uncertain from what point the other two 
came, but it is fuppofed that they came from the fame 
with the former. The || velocity of thefe has been 
much lefs than that of the Lifbon earthquakes : this 
appears from the interval between the preceding noife, 
and the fhock, as well as from the wave-like motion 
before- mentioned. 
* See Philof. Tranf. vol. xlix. p. 414. or Hi ft. and Philof. of 
Earthq. p. 315. 
f See Art. 97. 
j See Philof. Tranf. vol. 1 . p. 9. 
|j As in feme earthquakes the velocity, with which they are 
propagated, is much lefs than in others, it is evident, that they can 
by no means be owing to any caufe refiding in the air : for any 
fhock communicated to the air, muft necellarily move with a ve- 
locity neither greater nor lefs than that of founds j that is, at the 
rate of about thirteen miles per minute. 
18. Alt 
