The first stylograph pen was patented in 1875 and, although they were largely superseded by the 'nibbed' pens, they were still made in small numbers into the 1920s. Some specialist pens, used mainly for drawing, are still made today.
This curiously named 'Dwarf Imperator' is an 'own brand' stamped De La Rue Nota Bene stylograph introduced at the end of the nineteenth century. It was made around 1908 for the 'Army and Navy Stores' and is stamped A&NCSL. The last photograph shows a Nota Bene and the Imperator.
The pen is constructed in red hard rubber with the remnants of a chasing pattern. Parker called the colour 'Cardinal Red' in their 1906 Red Giant pen as did Waterman with the early '52' pen.
The stylograph uses a fine wire with a sprung section to control the ink flow through a fine tube in the section. The wire is still present in this pen, but I suspect it may be a few mm. shorter than it once was, I filled the pen and it did write but ink flow was patchy and it's not the easiest of writers.
The early stylographs are primarily of historical interest and are very collectable. It represents the first practical pen with a built in ink reservoir but met its demise with the advent of eyedropper 'nibbed' pens. The first De La Rue nibbed pen was called 'The Anti Stylograph'