Definition of valedictory | Bee Dictionary of English

n a farewell oration (especially one delivered during graduation exercises by an outstanding member of a graduating class)
a of or relating to an occasion or expression of farewell
a valedictory address
valedictory praise for his uniformly manly course
a suitable valedictory gesture
s of a speech expressing leave-taking
a valedictory address

Harry Truman worked hard on his eighth and last message to Congress on the State of the Union, determined to speak his valedictory in the calm, reasoning voice of the statesman.
So I've been searching for valedictory encomiums.
The second of Philadelphia's great medical Da Costas last week delivered his valedictory to Medicine, his prolog to Death.

Congratulations SVHS graduates!
Class of 2013 president Emily Deanne offers her valedictory address to the 500 or so people on hand Saturday during Shepaug Valley High School's commencement ceremony on the school campus in Washington.
June 16, 2013 - The News-Times
Shepaug Class of 2013 graduates amid cheers
Class of 2013 president Emily Deanne offers her valedictory address to the 500 or so people on hand Saturday during Shepaug Valley High School's commencement ceremony on the school campus in Washington.
June 16, 2013 - The News-Times
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Class of 2013 president Emily Deanne offers her valedictory address to the 500 or so people on hand Saturday during Shepaug Valley High School's commencement ceremony on the school campus in Washington.
June 16, 2013 - The News-Times

John Danforth in New York Times
It was very unusual, I thought,Mr. Danforth said. "I think it was a man who was relaxed and funny and looked as though he was about to shed this burden of the presidency. In a way, his speech seemed kind of like a valedictory. I took it as...
Andrew Turnbull in Telegraph.co.uk
But in a statement today, Lord Turnbull said: "The FT article does not give a balanced account of my views nor of the conversation I had with the FT which covered a much wider range of issues. I am on record - eg in my Valedictory Lecture in July...
Sharyn McCrumb in Asheville Citizen-Times
Then, McCrumb writes, "the front door opened bringing in a blast of cold air, and, with a few more valedictory wheezes, the reporter passed through it and was gone."