A Popular History of Astronomy During the Nineteenth Century / Fourth Edition

by Agnes M. Clerke

[415] Observations at Redhill, p. 8.

[416] Op., t. iii., p. 402.

[417] Rosa Ursina, lib. iv., p. 601. Both Galileo and Scheiner spoke of the apparent or "synodical" period, which is about one and a third days longer than the true or "sidereal" one. The difference is caused by the revolution of the earth in its orbit in the same direction with the sun's rotation on its axis.

[418] Rosa Ursina, lib. iii., p. 260.

[419] Faye, Comptes Rendus, t. lx., p. 818.

[420] Ibid., t. xii., p. 648.

[421] Proc. Am. Ass. Adv. of Science, 1885, p. 85.

[422] Observations at Redhill, p. 221.

[423] Am. Jour. of Science, vol. xi., p. 169.

[424] Month. Not., vol. xix., p. 1.