Harriet Beecher Stowe‘s bestselling novel Uncle Tom’s Cabin [wikipedia] provided fertile material for propagandists and advocates on all sides of the slavery controversy. Even before its initial publication in book form (1852), it had been adapted for the stage in multiple (and ideologically opposed) versions.
According to the London Times (3 Sept. 1852):
Uncle Tom’s Cabin is at every railway book-stall in England, and in every third traveller’s hand.
Here the complacent sentimentalism of the popular American tune Mary Blane takes on a more urgently critical (if equally sentimental) tone to lambast
…those sordid knaves
Across th’ Atlantic sea.
Who traffic thus in human flesh,
In a land they boast as free !
Uncle Tom remains an idealized character, without human complexity — but he evokes sympathy (“kind pity’s tear”) and his case calls out for action to address the injustices described.
To quote again the same edition of the London Times:
Euclid, [Stowe] well knows, is no child for effecting social revolutions, but an impassioned song may set a world in conflagration.
Compare the above sentiment to the reciprocal criticism levied at British industrialists in Jordan Is a Hard Road to Travel No.s 4 and 5:
For more Uncle Tom songsheets, search “Broadside Ballads Online from the Bodleian Libraries”… (especially this medley!)