PHYSICAL ano LITERARY 10; 
ne eo. 
An cafy Method of computing the Parallaxes of 
the Moon * ; by —————— 
ry AB. IV. fig. 1. 1. If from Q, the 
center of the fun, a right line OW 
be carried round, always touching the. 
earth’s furface, this line will form a coni- 
cial furface; which, being cut, bya plane 
pafling through the center of the earth, at 
right angles to the line joining the cen- 
ters of the fun and earth, the fe@tion fo 
made is the difk of the earth. 
2. THE fame conical furface will cut 
off a circular portion of the moon’s {phere 
wanes; within which, any arches, inter- 
cepted by lines drawn from the center of 
the fun and extended to the difk of the 
earth, will be nearly in the fame propor- 
| tion 
® Nov. 6: 1755 
