I recently wrote about a MacNiven & Cameron 'The Cameron Pen', dating from around 1912. The pen is, essentially, a bulb filler but it originally had two metal bars that were used to compress the sac, much like a modern 'aerometric' affair. I have now finished work on the pen but am still unable to source the filler bars, but I live in hope.
It's a hard rubber pen, in outstanding condition, with no signs of oxidation, it must have been kept in the dark for most of its life. It uses a full length ink sac so all of the the whole pen is used for ink storage, although complete filling is another matter.
The pen was offered with a choice of four nibs, this pen has the 'Hindoo' nib.
It's quite a large, elaborate 14 Ct. gold affair, with a separate, patented overfeed strip along the top which keeps the nib supplied with ink when flexed. It writes with a broad line and a good amount of flex:
