Inexhaustible Source

A mind which has once imbibed a taste for scientific inquiry, and has learnt the habit of applying its principles readily to the cases which occur, has within itself an inexhaustible source of pure and exciting contemplations.

-- Sir John Frederick William Herschel, 1st Baronet (1792 - 1871), English polymath active as a mathematician, astronomer, chemist, inventor, and experimental photographer, A Preliminary Discourse on the Study of Natural Philosophy (1831)