Genius and the Lighthouse

[I]t must not be supposed that genius (but the disease is now stamped out in the British Isles, the late Lord Tennyson, it is said, being the last person to suffer from it) is constantly alight, for then we should see everything plain and perhaps should be scorched to death in the process. Rather it resembles the lighthouse in its working, which sends one ray and then no more for a time; save that genius is much more capricious in its manifestations and may flash six or seven beams in quick succession (as Mr Pope did that night) and then lapse into darkness for a year or for ever. To steer by its beams is therefore impossible, and when the dark spell is on them men of genius are, it is said, much like other people.
 

—Virginia Woolf, Orlando (1928)