Hello TexasSprite,
that was the inventor's name, Watt. (More of a steam engineer, and I suspect that someone spotted the principle and used it on a car)
At least Wikipedia is a little more grammatically correct with the apostrophe s.
Aston Martin used this system on their DB4,5 and 6 series cars. Later cars used a De Dion system. Incidentally they had another system on the DB3 racing car which was a pin protruding from the rear of the differential which rode in a vertical channel on the chassis. This effectively prevented any sideways movement of the axle. Wear would be a factor I would think if this was used on a road car.
Alec