Refer nowadays to Phineas Taylor Barnum (1810-91)—once among the most recognisable and talked about of all nineteenth century Americans— only to conjure up visions of Barnum & Bailey’s three-ring circuses, menageries, acrobats, and Jumbo the elephant. Such images tend to obscure that in 1880, on creation of the famous travelling circus combination, the renowned Connecticut-born showman was already over 70 years of age, even if long prominent as an impresario and...