Hello,
While searching through the web I found the publication titled "Trademarks of the jewelery and kindred trades", published in 1922. Here is few pages on fountain pens that I (at least) found very, very interesting. What caught my eyes is a sign used by Salz Bros and which looked like Penkala pens trade mark ... also there is a small mistake according John Holland brands: FountOgraph instead Fountagraph.
Enjoy!