tog ESSAYS any OBSERVATIONS 
fame angle from the points V and C; and 
confequently it is the meafure of the vif. 
lon. »@ «. But the truelon. is d/=ag: 
Therefore v g—ag=va is the par. lon. » 
é@@- Again, ad=/g=vif. lat. >) 40; and 
¢ed=fl=tr. lat.: Therefore v b=ac=ad+ 
dc=par. lat.) 40. 
6. But thefe parallaxes va, vb, and 
the vif; lon. and lat. vg, vi, fuppofe the 
fpectator at the point V on the difk ; 
whereas his true place is at the corre= 
{fpondent point of the furface of the earth ; 
_ confequently, the vif. lon. and lat. » 20, 
vg, vf, muft be increafed in the ratio of 
the diftance of the point v from the {pec- 
tator’s place on the furface, to its diftance 
from the point V on the difk. But, as 
the horizontal femidiameter of the moon 
fhould tikewife be increafed in the fame 
ratio, it will equally anfwer the purpofe 
of finding the times and phafis of an 
eclipfe, to let thefe continue unaltered, 
and to diminifh the fun’s apparent femi- 
diameter in the fame ratio. 
7. LET Cr be the axis of the earth pro~ 
jected on the difk, FMD the ellipfe into — 
a which 
