How passing sad! Listen, it sings again!
Art thou a spirit that, amongst the boughs,
The livelong night dost chant that wondrous strain,
Making wan Dian stoop her silver brows
Out of the clouds to hear thee? who shall say,
Thou lone one! that thy melody is gay,
Let him come listen now to that one note,
That thou art pouring o'er and o'er again
Through the sweet echoes of thy mellow throat,
With such a sobbing sound of deep, deep pain.
I prithee cease thy song! for from my heart
Thou hast made memory's bitter waters start,
And filled my weary eyes with the soul's rain.

Frances Anne Kemble

http://www.poemhunter.com/poem/to-the-nightingale-7/