The 1880s saw a brief explosion of experimental manually-operated repeating handguns, mostly throughout Europe. The most common weapon of this type known in the US is the Volcanic pistol, forerunner to the Winchester lever-action rifles. In Germany and Austria, however, a bunch of different guns of this type were developed.
The one we are looking at today is a Berger, dating from 1880/1881. Unlike most of these guns, it could be described as a double action mechanism - a single rearward trigger pull runs the complete loading/firing/ejecting cycle. In most manually operated handguns, the rearward pull loads and fires, while a forward push of the trigger extracts and ejects the fired case (much like a lever-action rifle).