"Kin" by Carl Sandburg
Brother, I am fire
Surging under the ocean floor.
I shall never meet you, brother
Not for years, anyhow;
Maybe thousands of years, brother.
Then I will warm you,
Hold you close, wrap you in circles,
Use you and change you
Maybe thousands of years, brother.
What figurative device is used in the phrase "I am fire," found in the first line?