Dad sent in a lovely, old favorite:

The Arrow and the Song

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 afterward, 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.

-Henry Wordsworth Longfellow

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For those of you interested in Physics, Photography or notable Boston stuff, this is the epitaph on Harold Edgerton's grave in Mount Auburn Cemetery.