Current reads, one fits #NaturalLitsy.
It was your cruelty to him that made him disappear by that same“under ground rail-road“ or “steam balloon,“ about which one of your city constables was swearing so bitterly . . .
Thomas Smallwood in his laughingstock letters August 10, 1842
First mention in print of an underground railroad helping slaves escape north, per the tagged book. Within a few months it has been adopted across the nation for the ways slaves escape to freedom.