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

by Agnes M. Clerke

[318] Phil. Trans., vol. vii., p. 4007.

[319] J. Herschel, The Telescope, p. 39.

[320] Month. Not., vol. xxix., p. 125.

[321] A slight excess of copper renders the metal easier to work, but liable to tarnish. Robinson, Proc. Roy. Irish Ac., vol. ii., p. 4.

[322] Brit. Ass., 1843, Dr. Robinson's closing Address. Athenæum, Sept. 23, p. 866.

[323] The Telescope, p. 82.

[324] Lord Rosse in Phil. Trans., vol. cxl., p. 302.

[325] This method is the same in principle with that applied by Grubb in 1834 to a 15-inch speculum for the observatory of Armagh. Phil. Trans., vol. clix., p. 145.

[326] Robinson, Proc. Roy. Ir. Ac., vol. iii., p. 120.

[327] Astr. Nach., No. 536.