The foldout brochures which measure 3inch X 6inch are fascinating, they are out there in large numbers from Massey-Harris, J I Case Plow Works and M-H Blackstone.
There are more categories than the "Form Adv" mentioned earlier and will list my findings below.
1. Early M-H of Canadian, American and Britsh origin have no markings.
2. Form ADV numbers 1 to 338, all countries.
3. List numbers 1 to 220 mostly USA and Great Britain
4. Letters - numbers, (example F-13, I-91, J-4W, J-14) mostly early USA and Great Britain
5. Numbers - letters (example 247-1-37W
I have checked my files and list this morning and have 185 in total so far which is only a very small amount of the list above and I do not know how high the numbering went, 338 is my highest in the "Form Adv" list and 220 is my highest in "list numbers".
I expect Keith Oltroggee could help us out here with more.
Has anyone any with higher numbers than these?, if so please let us know, then my "wanted" list will grow, like Tom I hoped to get as near a complete set as possible, that was in the early 90's and still a long way to go.
I will post some pictures shortly showing some of the variations.
Then of course there are the larger sized foldouts like Tom has just posted, a lot of these seem to have more of the Canadian origin and connection