W. B. Yeats - Another Song of a Fool 汉译

This great purple butterfly,  

In the prison of my hands,  

Has a learning in his eye  

Not a poor fool understands.  

Once he lived a schoolmaster     

With a stark, denying look,  

A string of scholars went in fear  

Of his great birch and his great book.  

Like the clangour of a bell,  

Sweet and harsh, harsh and sweet,  

That is how he learnt so well  

To take the roses for his meat.