Smith, Hamilton Lanphere, 1819-1903. [from old catalog] · Cleveland, M. C. Younglove and company · leaf 81
ollowing diagram. The*sun being situated, not in its centre, but nearer one side, in whatis called one of the foci of the ellipse. The foci of the ellipse Sand C, are so situated on the major, or longer axis, of the ellipse,that the sum of the length of any two lines drawn from the foci tothe same… … length of the major axis A B. By placing two pins, one at eachfocus of the ellipse, and tying a thread around them of such lengthas will give the requisite major axis, a true ellipse may be described,by stretching the string and moving a pencil around in the angle.In the preceding diagram, we may…
Astronomy · Meteorology · Geology · Paleontology
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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-321-212.webp)
