Ça ira, “It will go on,” a popular song in France during the Revolution, said to have been a phrase of Benjamin Franklin's, which he was in the habit of using in answering inquirers about the progress of the American revolution by his friends in France.
Definition taken from The Nuttall Encyclopædia, edited by the Reverend James Wood (1907)
Cain, Thomas Henry Hall * Caird, Edward