Imperial camera company falling plate box camera. I recall dating it to the 1890s but I don't remember where I got that information now.
Contains 12 plate holders which operate on a falling plate mechanism controlled by a lever on top - with a counter to indicate the exposures taken! The plate holders can be adapted for paper-negatives or film with a simple insert made out of black construction paper. I have made a couple of those (seen in the images) but never actually got around to shooting film in this.
Lens and shutter are meniscus with rotating spring-disk shutter. The shutter was seized when I got it, and I refurbished it so that it now works well. Two exposure settings, time and instant. Two aperture settings: big and small. Falling plate mechanism works very well and makes a ridiculously satisfying KER-chi-CLUNK sound.
I've used it for a couple of paper negs (unfortunately my paper neg technique is bad), but I think for film use you'd want to seal up the back a bit better (it just relies on a tight fit between the wood pieces, and I think for proper light sealing you'd probably want some felt installed.
Very interesting collectible, and the size is true 4x5".