Don't forget the New Haven Pulp and Board company on East Street built in 1901 and later became Simkins Industries. They produced paperboard and folding cartons.
These micro histories are wonderful. But there are some themes that run throughout,,,,such as amazing entrepreneurship...which as has been stated make the New Haven of the 1800's the Silicon Valley of that era. The Brewster carriages lead all the say to the 1950's and the first VW Franchise in the US.