Middlesex 759Bis, Spence's (Dalton & Hamer, page 170)

Denomination: halfpenny
759Bis.  O: A man fettered, and a padlock on his mouth. A FREE-BORN . ENGLISHMAN
            1796. Same for Nos. 757-759.
         R: A cat. MY FREEDOM I AMONG SLAVES ENJOY. 1796. As No. 680.
         E: Milled.

In Addenda, page 543.

Keywords

a free-born englishman 1796,my freedom i among slaves enjoy,1796