Robert Frost (March 26, 1874 – January 29, 1963 / San Francisco)

Before man to blow to right
The wind once blew itself untaught,
And did its loudest day and night
In any rough place where it caught.

Man came to tell it what was wrong:
It hadn't found the place to blow;
It blew too hard - the aim was song.
And listen - how it ought to go!

He took a little in his mouth,
And held it long enough for north
To be converted into south,
And then by measure blew it forth.

By measure. It was word and note,
The wind the wind had meant to be -
A little through the lips and throat.
The aim was song - the wind could see.