We're in need of 6 replacement lock sets in the Sullivan House. They are called:
"The Junior" Vulcan Locks (Cycloid Knob Action)
Yale & Towne Mfg Co
Sole Makers of
The Yale Locks
Stamford, Conn USA
and were apparently produced in 1898. From photos I've seen online, they all appear to be the same make. They have a rounder, slimmer shape with the knob hole closer to the edge than in any other mortise locks I've ever seen. We had an entire bin of mortise locks in the house - none match. Nor do any of the hundreds at the antique store on Third. The Architectural Salvage Warehouse is temporarily closed so I haven't been there, but it seems extremely unlikely they'll have any at this point. As mortise locks go, I got the kooky rare ones.
I currently see one for $15 on Ebay. Beyond that, I haven't been able to find any. If anyone comes across such a thing, I'd be highly interested in getting them. I'm not keen to butcher my original wooden doors to fit a bulkier lock.
These were exclusively used on interior doors, as far as I can tell.
Again, the defining characteristics that distinguish it, even at a glance, are the proximity of the knob and keyholes to the edge, and the roundness of the corners.