Light.
Herschel, Sir John F. W. No. 7 in **£.191.6 On the absorption of light by coloured media. Edinb., 1823, Plate. 4°. Same, (In Royal soc. Trans. v. 9, pp. 445-460. 2 plates. Edinb., 1823, 4°.) *#E.163.1.9