Larry,

I count at least 18 Thonons or hyphenated Thonons. The family extended from the 1830's (or earlier) to at least the 1960's. There was even a damascus pattern called thonon.

Go to the bottom of this page:
http://www.damascus-barrels.com/Image_Barrels_2.html

Which leads me to believe that some Thonon at some time patented this pattern.

Jules was around from 1908-1925. He was in business with Duchateau.

Fernand had a large operation, that began about 1903. How long it continued I am not sure.

Pete

http://www.damascus-barrels.com/Movie.html