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to you ; and afk leave, for my own Information, juft 
to query, what center thefe bodies may moft pro- 
bably be fuppofed to revolve round ? Either the 
Earth or the Sun feem to bid faireft for this. 
1. A body revolving round the Earth in a circle, at 
the height of about 40 or 50 miles, would move but 
7 miles in a fecond ; and in a very eccentric orb, near 
a parabola, but 10 miles: which falls much fhort of 
the velocity of your Meteor, which was of 30 miles 
in a fecond *. 
2. The Earth’s annual velocity round the Sun is 
near 16 miles in a fecond ; and a body revolving in 
a very eccentric orb would have, at the fame diftance 
from the Sun, a velocity of 22 miles in a fecond. 
Wherefore if the Earth and fuch a body near it were 
moving in the fame direction, that body would get 
before the Earth with a relative velocity of 6 miles in 
a fecond; but, if moving the contrary way, it would 
be left behind with a relative velocity of 38 miles in a 
fecond : And this is the greateft pofhble relative ve- 
locity. Bodies moving in oblique directions may 
have any relative or apparent velocity lefs than this 
maximum. This fuppofition therefore agrees better 
with a velocity of 30 miles in a fecond, than the 
former; but I fhall be much obliged to you for your 
thoughts on this point. 
As to our late Meteor of May 1759, I have not 
been able to come at any farther particulars than 
what are contained in my letter to Dr. Birch, ex- 
cepting only as to the loudnefs of the report, at a 
great didance from the place of explofion. An in- 
telligent man of this town has fince informed me, 
that he was then fifhing in a boat at anchor about a 
"* Vid. Philof. Tranf. Vo!. LI. p. 263. 
mile 
