Star-land : being talks with young people about the wonders of the heavens (1891)
Ball, Robert S. (Robert Stawell), Sir, 1840-1913 · London ; Paris : Cassell & Co. · leaf 267
onof the message is to be one hundred and twenty-three de-grees and forty-five minutes. 252 Star-Land. the parabola. Generally speaking, great comets come to us onceand are then never seen again. Such bodies do not movein closed ovals or ellipses, they follow another kind of curve,which is… … Fig. 72.—The Path of a Projectile is a Parabola. every time a ball is thrown into the air it describes a partof that beautiful curve which geometers know by thisword (Fig. 72). In fact, you could not throw a ball so thatit should describe any other curve except a parabola. Noboy could throw a stone…
Astronomy
Internet Archive · Wellesley College Library · Public Domain Mark 1.0. Free to use for anything.
