No. 432 & No. 422 Stylograph
The 422 and 432 are stylographs or 'ink pencils'. Companies like Cross and MacKinnon led the design of stylographs in the 1800s, and this type of pen became quite popular in the early 1900s. Old Montblanc catalogues introduce them as "no lead, no nib, yet ink".
The 422 was produced between 1932-41. It is a long pen. Notice the lovely imprint on its barrel. The clip on this pen is known as "papyrus" and I find it quite elegant. This 422 is a push-knob filler called "Stoßfüller" and "Stossfüller" in old catalogues. It was advertised as "a press of the button, that is the handling for the Montblanc; no losable individual parts and allowed single hand operation". It is similar to a button filler from the inside i.e. it has a sac and a pressure bar, but it has a push knob that allows for more comfortable action than the small metallic knobs on button fillers. The same mechanism was used on the prized 12x series.
The 432 is a stylograph like the 422, except it is a piston filler. This one is considerably shorter than the 422, it is more regular sized. The cap top and blind cap are in ebonite while the rest of the pen is in celluloid. It doesn't have a clip, instead, it has a black ring in the place of the clip. I don't know if this is original or not but it fits perfectly and looks great, so I'll just let it be. Considering the engraved cap bands, I date this pen to later in the WWII period of 1943-46 when restrictions placed on the use of metals caused MB to stop using cap rings whenever possible. The 432 was available in black, blue, and green.
One catalogue says "now the problem is solved" referring to the fact that these pens were great for making carbon copies. The red dot on 4xx stylograph cap tops refers to the line width of the nib - fatter dot means broader width and vice versa. Also, the thinner dotted pens were suitable for carbon copy writing, while the fatter dotted pens were appropriate for normal writing needs.
Hidden inside the section is the mechanism that makes the pen work - a lead weight attached to a thin needle feed housed in a small pipe. When the needle feed is pushed up into the nib tip due to pressure against the paper, it allows ink to flow out. The pic on the right from a 1932 catalogue explains the mechanism. I paraphrase, but the catalogues essentially explain that "instead of a gold nib, one writes with a finely rounded tube made of platinum-iridium alloy which prevents scratching on paper. The writing tube does not have the subtleties of a gold nib, one cannot achieve calligraphic typeface, but a large number of copies. There is also a thin needle feed inside the tube which moves which is made of gold wire".
These stylographs were not expensive back in the day, but they are rare to find now - especially in working condition!
Rösler, J., & Wallrafen, S. (2014). Collectible Stars I: 1908 - 1947.