Copyright © Françoise Herrmann
Ah, the endless flow of a fountain of ink...!
Oh, what a mess...!
To date leak-proofing fountain pens remains an issue, especially in pressurized plane cabins (see for example the post on LouisVuitton’s 2015 fountain pen patent).
In 1894, “escaping ink” appeared as no less of an “annoyance”. Wirt’s fountain pen cap was designed precisely to “overcome this objectionable action of the pen” [L 20-22, p.1]! Thus, the invention disclosed in US526428, titled Fountain-pen, and granted on Sept. 25, 1894, precisely addresses this leak-proofing issue with the design a special cap.
The cap disclosed in US526428 includes a longitudinal and recessed component within, designed to receive the pen point and to abut against the nozzle, in view of forming a joint to prevent ink from escaping, when the pen was not in use, or when it was positioned horizontally inside a pocket.
It is further specified that the longitudinal recessed component inside the cap could be made of flexible or hard rubber, the main purpose being to seal the nozzle when the pen was not in use.
Below, the figure drawings extracted from US526428, including a key, appended and layered onto the sheet for easier comprehension and translation.