What is shaft of light?

Famous quotes containing the words light and/or shaft:

    It is a light thing for whoever keeps his foot outside trouble to advise and counsel him that suffers.
    Aeschylus (525–456 B.C.)

    The subterranean miner that works in us all, how can one tell whither leads his shaft by the ever shifting, muffled sound of his pick?
    Herman Melville (1819–1891)