An introduction to astronomy : designed as a text book for the students of Yale College (1846)
Olmsted, Denison, 1791-1859, Yale College (1718-1887) · New York : Collins, Brother & Co. · leaf 117
hody revolves about an immovable center of force, andis constantly attracted to it, it will always move in the same plane,and describe areas about the center proportional to the times.* Let S (Fig. 35,) be the center of force, and suppose a body tobe projected at P in the direction of PQR, and take… … let a single impulse act at S, sufficient to draw the body throughQV, in the time it would have described QR ; and complete theparallelogram VQRC, and the body in the same time will describeQC ; therefore, PQ, QC, are described in the same time. Butthe triangle SCQ=SRQ=SPQ ; that is, equal areas…
Astronomy
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![An illustration from Nicolai Copernici Torinensis De reuolutionibus orbium coelestium, libri VI : Habes in hoc opere iam recens nato, & aedito, studiose lector, motus stellarum, tam fixarum, quàm erraticarum, cum ex ueteribus, tum etiam ex recentibus obseruationibus restitutos: & nouis insuper ac admirabilibus hypothesibus ornatos. Habes etiam tabulas expeditissimas, ex quibus eosdem ad quoduis tempus quàm facillime caculare poteris. Igitur eme, lege, fruere. [Line in Greek] (1543)](https://img.insideoutlibrary.com/img/200/ia-nicolaicopernici00cope-201-122.webp)
