Nos 8 in **#E,191.6 Herschel, Sir John Frederick William, bart.
On a remarkable peculiarity in the law of the extraordinary refraction of differently=coloured reys exhibited by certain varieties of apophyllite. Camb. 1821. (1), 7, (1) pp. 4°.
From the Transactions of the Cambridge philoss» soc. *5290a«1.1 «
- Refraction,