£64 Description and Use of the

to the right ascension of the pole star whenit is less than the sun's, the remainder willbe the time of the star’s coming to the me-ridian.

Then, as before, hang up two plumb lines,between your eye and the polar star.

PROBLEM LVJ.

Of the equation of time.

306. As time flows with great regula-rity, it is impoflible to measure it accurate-ly, and compare its several intervals witheach other, but by the motion of some ofthe heavenly bodies, whole progress is asuniform and regular as itself.

Ancient astronomers looked upon the funto be sufficiently regular for this purpose;but by the accurate observations of laterastronomers, st is found that neither thedays, nor even the hours, as measured bythe sun’s apparent motion, are of an equallength on two accounts.

1 st, A natural or solar day of 24 hours,is that space of time the sun takes up inpassing ffom any particular meridian to thesame again ; and one revolution of the earth,

with