Rhode Island Postal History - Cancel Varieties
Wesson Cancel - (Time On Bottom) 
Providence, Rhode Island June 7, 1886
(Scroll Down for Background History of Wesson Cancels)

The Wesson - Time on Bottom, (TOB) cancels were named for Mr. Walter D. Wesson of Providence, RI, who invented a new type of duplex postmarking device. The device showed the Month, Day, Year, and Time, and could be changed by removing and inserting slugs in a holder on the canceling devices handle.

Wesson Type 2 Cancels were in use by many cities during the Banknote Era. The Type 2 dial places the city name in an arc at the top of the dial as shown above. The Type 1 Dial was only used in Worcester, Massachusetts, which also lays claim to the Earliest Known Usage, (EKU) for a Wesson Cancel on July 2, 1881.