A dictionary of the Kalispel or Flat-head Indian language, ... - Page 207
Joseph Giorda - 1879 "GUM roof o Ies gumminem gummin gummint v tr 11 I ardently wish fop him or it I long for him for an object not possessed yet Gummin s Object of ardent desires les gummi ftcm gummiltcn gum milt v rel 16 I long for his "
Earliest 'gummint' for government i could find at google books is. Electric light & power - Volume 30 - Page 142
books.google.ca/books?id=xYsnAAAAMAAJ Ell C. Bennett - 1951 - Snippet view - More editions President Hoover may have impressed you — Eisenhower's nomination may have bothered you — Senator Magnuson's blather about 'gummint' power may have made you mad — Colonel lake getting Stevenson's draft call arranged may ...
I noticed that google book's search engine swapped gummint for government when I did a search for gummint magnuson