PHILOSOPHIA NATURALIS

44i

Di Mundi

Syst “ ute PROPOSITIO XXXI. PROBLEMA XII.

Invenire motum horarium nodorum lunae m orbe elliptico.

Designet E? maq ellipsin, axe majore Qq, minore a b descrip-tam, GpAqB circulum circumscriptum, T terram in utriusque cen-tro communi, <5 solem, p lunam in ellipsi motam, & p m arcumquem data temporis particula quam minima describit, N & » nodos

linea Nn junctos, p K & mk perpendicula in axem $)j demissa 8thinc inde producta, donec occurrant circulo in 5P & M, & lineaenodorum in T) & d. Et si luna, radio ad terram ducto, aream de-scribat tempori proportionalem, erit motus horarius nodi in ellipsiut area p^Ddm & AZq conjunctim.

Nam