Jim Feldman’s definitive AC collection begins with this delightful example of the company’s earliest offering, the three-wheel, single-cylinder Sociable, one of several styles of the “Tricar” that had been introduced in 1904.

The Tricar was inspired by the vision of founder John Weller, a gifted if opinionated engineer, and his financial partner, John Portwine, the successful owner of a string of butcher shops in London.

After Weller’s first design, an innovative 20-horsepower runabout, proved too expensive to sell competitively, Portwine suggested a simple—even elemental—three-wheeler to meet the delivery needs of his shops and others in crowded London.

The resulting AutoCarrier was an immediate success.

Its two front wheels straddled a box.

The driver sat behind, steering with a tiller and simple hand and foot controls.

The engine, a 5 RAC horsepower air-cooled T-head single, resided under the driver’s seat and drove the single rear wheel through a chain.

Within the driving wh...