Waterman's 112 Pump Filler

I found this pen at a flea market in 2021 in a junk box marked "$2/pen." Turns out I stumbled on a rare and valuable model of Waterman's.

Quoting directly from Nishimura's site: "The end of the barrel was unscrewed and then gently oscillated. The mechanism was described in two patents, issued in 1897 and 1900, but it appears as if production did not begin in earnest until around 1903. These pens are rare, and though they were not consistently featured in advertisements and catalogs, this is as likely to be a result of their lack of popularity rather than the cause. Although some state that the pump-filler was dropped around 1910, when the sleeve-filler was introduced, scattered listings appeared as late as the early 1920s, which has led to speculation that this was done to keep up patent rights."

https://www.vintagepens.com/Waterman_self-fillers.shtml