Eudoxussupposedthatthemotionofthesunorofthemoon
involves，ineithercase，threespheres，ofwhichthefirstisthe
sphereofthefixedstars，andthesecondmovesinthecirclewhich
runsalongthemiddleofthezodiac，andthethirdinthecirclewhich
isinclinedacrossthebreadthofthezodiac；butthecirclein