To begin with, writers dipped something pointed into a container of some colored liquid and wrote until the dip ran out, usually a few words, then repeated the process. This worked pretty well, and the pointed object was gradually improved from a stick to a quill to a holder tipped with a metal pen which we now call a nib. A major problem, though, was that this system was not easily portable.
Transporting this container, usually glass, required both a good seal and a sturdy protective covering for the glass. Using the system on the move was almost impossible, and getting set up to write in a fixed location required considerable effort. The idea that the holder for the nib could be hollow and contain ink, ready to flow out at a moment’s notice, led to the first iteration of the fountain pen – a self-contained writing instrument.
Since the filling system – lever, crescent, piston, etc. – had not been invented, the user of an early fountain pen had to remove the nib from the hollow holder, use an eyedropper to fill the ink compartment, then replace the nib into the holder, all without spilling too much ink. Inky fingers were the mark of the early fountain pen owner.
One improvement to the system was the development of a nib and feed section that screwed into the holder or barrel. This made it considerably easier to remove and replace the nib, but it created a joint which could, and did, leak.
The fountain pen could be filled and ready to write, but the next problem was how to keep the ink in the pen while carrying it around. The cap was the next improvement. The first caps were slip caps, which means that they were cylindrical covers that slipped over the nib and were held in place by friction with the holder. Needless to say, caps that slip on can also slip off, with predictable results. Ink-stained shirt pockets were the next mark of the fountain pen owner.
All of this leaking inspired inventors to find a better way to fill the pen and contain the ink. Eventually inspiration would lead to the self-filling fountain pen, with Conklin’s Crescent, Sheaffer’s lever, and many others. But, an extremely unlikely development appeared first: the non-leakable safety pen.
The name safety was a marketing gimmick intended to divert buyers from the older manufacturers’ products to those of the new, high-tech manufacturers. Their claim was that the safety pen would not leak, and the market responded, hoping for the best.
We know that the claim was false, not only because the safety pens did leak, but because even in 2013 there are discussion threads on various fountain pen forums about which pens do or do not leak when carried on airplanes or simply to higher elevations.
I have had a slip-cap eyedropper-filled pen for some time. It is a Laughlin and belonged to my grandfather, who must have had inky fingers and perhaps an ink-stained shirt or two. The pictures below show the Laughlin and are annotated to point out the features of this type of pen.
I recently acquired my first safety pen, a Moore’s Midget, and after a little fiddling with it to understand its operation, it became quite clear that rather than being non-leakable, the designers had simply swapped one set of problems for another. It is still filled with an eyedropper, with all the mess that implies, but instead of removing the nib and feed from the barrel, one retracts the nib down into the barrel and adds ink into the resulting opening.
To write, the nib is slid out of the barrel, where it was immersed in the ink, and wedged into place in the open end of the barrel. Closing the pen for transport requires retracting the nib, then screwing the cap firmly over the open end of the barrel. This design eliminates the joint between barrel and nib/feed section, but adds a sliding seal at the bottom of the barrel to allow the nib/feed to move within the barrel. Further, the user must remember to hold the pen in a vertical position while capping and uncapping, otherwise the ink will pour out around the retracted nib. Also, if the cap unscrews just a bit, the seal keeping the ink in is broke and leaks are inevitable.
The self-filling pen replaced both the standard eyedropper and the safety, eliminating the eyedropper and its mess and reducing the number of ways that the pen could leak.
Here are some pictures of my Moore’s Midget: