Page from L. E. Waterman Company Catalog Advertising Waterman's Ideal Fountain Pens, circa 1915

Many pen inventions during the early 20th century attempted to simulate the hollow channel of the goose-feather quill pen but ensure a smooth, controlled flow of ink. For Waterman's Safety Pen, introduced in 1907, the user would fill the barrel with the day's supply of ink using an eyedropper, then screw down the cap to seal the barrel.