Read the following poem and answer the questions that follow:
SMOKE
Light – winged smoke! Icarian bird,
Melting thy pinions in thy upward flight:
Lark without song, and the messenger of dawn,
Circling above the hamlets as thy nest:
Or else, departing dream, and shadowy form
Of midnight, vision gathering up thy skirts:
By night star-veiling, and by day
Darkening the light and blotting out the sun:
Go thou, my incence, upward from this hearth,
And ask the gods to pardon this clear flame,
Henry David Thoreau

Which figure of speech is implicit in ‘light winged smoke!’?