"Liverpool Blackballer"?`

[Joel S. Berson]

What is a "Liverpool Blackballer"?

"The staircase and passage-way [of the American Consulate] were often
thronged, of a morning, with a set of beggary and piratical-looking
scoundrels, (I do no wrong to my own countrymen in styling them so,
for not one in twenty was a genuine American,) purporting to belong
to our mercantile marine, and chiefly composed of Liverpool
Blackballers and the scum of every maritime nation on earth; such
being the seamen by whose assistance we then disputed the navigation
of the world with England."

Hawthorne, "Our Old Home", 1863 (MS).