I shot an arrow into the air,

It fell to earth, I knew not where;

For, so swiftly it flew, the sight

Could not follow it in its flight.

I breathed a song into the air,

It fell to earth, I knew not where;

For who has sight so keen and strong,

That it can follow the flight of song?

Long, long afterwards, in an oak

I found the arrow, still unbroke;

And the song, from beginning to end,

I found again in the heart of a friend.

﹝美﹞朗费罗（H. W. Longfellow）