I have a debt of gratitude to you all. To think I was stuck on Nana serving tea and pastries. I haven't read anything yet about Dominion Rubber making anything but galoshes, but who knows?
The interesting thing about all this is that on the date of the census (June 1st) my grandmother was at least seven months pregnant and unmarried, so her employment at the factory would have been extraordinary. Did her employers know? Did she hide her pregnancy under a coverall? She was a tiny woman (4'10") so, if she was on the factory floor she must have been a tough cookie.
My grandfather married her the next month in Montreal, the child died, and Nana moved onto a respectable, middle-class life with seven more children, too busy to work outside the home.
Once again, thank you all. What a bunch of miracle workers.