The Ohio River runs through C. E. Morgan’s second novel, THE SPORT OF KINGS (Farrar, Straus and Giroux, $27). It’s a “hungry current,” a “sucking current,” a “swamping weight” whose black surface moonlight cannot pierce. It cleaves the green, fertile karst of Kentucky and the choking industrial cities of the North, a time-made path, wending through time. To swim across it, a runaway slave named Scipio kicks a drowning stranger in her pregnant belly rather than be dragged to death fathoms below. A hundred and fifty years later, toward the end of the twentieth…