What is the apostrophe example in Leda and the Swan poem

In the poem "Leda and the Swan" by W.B. Yeats, an example of an apostrophe can be found in the following lines:

"Being so caught up,
So mastered by the brute blood of the air,
Did she put on his knowledge with his power
Before the indifferent beak could let her drop?"

In this excerpt, the speaker is addressing Leda directly, as if she is present and able to hear him, even though she is a mythical figure. This use of apostrophe gives a sense of immediacy and intimacy to the poem.