There are a lot of cool firearms on the Forgotten Weapons Youtube channel, and a lot of strange ones, but this one is really odd.
The Frankenau Purse Gun, which was patented in 1876 in the U.S., UK, and Germany, isn't what most folks today would call a purse—it's more of a rigid change purse that your grandma might have had in her shoulderbag.
One side of the gizmo can actually hold coins, says this post from Gizmodo http://sploid.gizmodo.com/this-weird-purse-is-actually-a-gun-1786663511. The other side has a five-shot, 5mm pinfire revolver with the trigger tucked next to the purse’s hinge.
There’s a little port in the top of the box where the barrel is set. This example has clearly seen better days, because the swiveling muzzle cover, which would have kept obstructions out of the tiny 1cm barrel, is missing.
The trigger is actually a lever that rotates down from the hinge-edge of the purse, allowing the revolver to be fired. The little gun is double-action, meaning the trigger cocked and fired the hammer (which is just flopping around in the video because the spring is shot or missing), meaning this little self-defender could be fired while the purse was closed.
When the trigger was folded back into the body, the little cover would snap closed over the muzzle.
Pinfire guns used one of the earliest practical designs of a metallic cartridge with an integrated primer, though they presented their own safety problems.
The cartridge’s priming compound was ignited when the gun’s hammer struck a small pin, which protruded at a 90-degree angle from the case, just above the base. The pins fit into small grooves cut into the top of a firearm’s barrel or cylinder.
The first pinfire cartridges were made with a metal base and paper tubes. By 1846, the pinfire had evolved into metal cartridges with a base wad. They were used during the American Civil War, but not frequently due to their low power compared to percussion cap revolvers of the day, though they were popular in some navies, with some examples made of brass to resist corrosion.