C 45 + ] 
nation, BE, found as above, will be the meafure of 
the parallax in longitude, as afligned in the Coroll, to 
Prop, I. and if the point afTumed in the ecliptic be 
po° diftant from the moon’s true place, BE will ap- 
proach near enoughv to that parallax for the purpofe 
intended, " 
After the fame ipanner may the parallax in longi- 
tude be found for any other time aflumed. Alfo if 
the arch AC be taken equal to twice the comple- 
ment of the obliquity of the ecliptic, that is, BC 
equal to twice that obliquity, BE will be nearly equal 
to the parallax in latitude, provided DE be taken equal 
to the verfed fine, to the like fcale, as before, of the 
complement of the right afeenfion, of the point of the 
ecliptic on the meridian. And thus may be found 
the fittefi: interval of time for the three calculations of 
the parallaxes, Sec. I have above propofed in general 
an hour ; but in great eclipfes it would be beft to af- 
fume this interval fomething greater, and in fmall 
eclipfes lefs. 
Moreover thefe conftrudlions may be performed 
with very little trouble, any fmall fe^or being fufii- 
cient for the purpofe. 
XLV. Of 
