Definition of "inextinguible"

Cornelius Drible [hath made] a perpetual motion, inextinguible lights, linum non ardens, with many such feats […]

1624, Democritus Junior [pseudonym; Robert Burton], The Anatomy of Melancholy: […], 2nd edition, Oxford, Oxfordshire: Printed by John Lichfield and James Short, for Henry Cripps, partition II, section 2, member 4