19th Century Patriotic Shield Painting Featuring John Adams

Folk art patriotic shield painting of John Adams, dating to around 1876 and of a large size measuring 41" x 34.5". It is an oil on canvas laid down to boards. There is writing on the back of the boards, but I cannot make out what it says. There is another similar piece to this that features another signer of the constitution in the Smithsonian collection. This piece came from a collection in Portsmouth, NH and was featured in an article in the Detroit News from 1972 in another prominent Americana collection. It is truly a unique piece and has great presence.