was the first one to present a leakproof fountain pen. Waterman invented an inkfeed, that by using the principles of capillarity granted a regular exchange of ink from the reservoir (onto the paper) and air (into the reservoir). Waterman in the twenties had a marketshare of more than 30%. Already in the late twenties, Waterman introduced a cartridgefiller with glass cartridges. This was not a success. Injectionmoulded plastic cartridges, introduced in the 50ies with the Waterman CF were a great success.