[9] See my Treatise on Optics, Edit. 1853, Chaps. xxviii, xxix.

[10] Treatise on Optics, p. 120.

[11] See my Treatise on the Stereoscope, Chap. xi. p. 86.

[12] See Edinburgh Encyclopædia, Art. Civil Architecture, plate cli.

[13] See Hope’s Costume of the Ancients, vol. ii. plates 230, 264, 278, figs 1 and 298, fig. 2.

[14] See Journal of the Royal Institution, vol. v. p. 99.

[15] [See p. 93].

[16] A thin lens of rock crystal will transmit more of the actinic rays than one rendered achromatic.

[17] See the Journal of the Photographic Society, vol. iv. p. 137.

[18] This work is entitled, L’Optique des Couleurs, fondée sur les simples observations et tourné surtout à la pratique de la peinture, de la teinture, et des autres arts coloristes. Par le R. P. Castel, Jesuite. Paris, 1740.