Star-land; being talks with young people about the wonders of the heavens (1899)
Ball, Robert Stawell, Sir, 1840- [from old catalog] · Boston and London, Ginn & company · leaf 283
a part of the beautiful curve which geome-ters know by this word (Fig. 74). In fact, you could 270 STAR-LAND. not throw a ball so that it should describe any othercurve except a parabola. No boy could throw astone in a truly horizontal line. It will always curvedown a little, will always, in fact,… … Fig. 74. — The Path of a Projectile is a Parabola. slopes down again, part of a mighty parabola. So doesa tennis ball thrown by the hand or struck by the racket;though here, indeed, I admit that a spin may be givento the ball which will somewhat detract from the sim-plicity of its movement. In…
Astronomy
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