Spectrum. No. 7 in **E.191.6
Herschel, Sir John Frederick William, bart. On the absorption of light by coloured media, and on the colours of the prismatic spectrum exhibit- ed by certain flames .. . Edin. Weill. 1823. (2), 16 pp. Plate. 4°. From the Trans. of the Royal soc. of Edin. 1822
(**E.163.1.9].