It is not possible to see any internal structures clearly in the pictures. A sketch of what is inside would be good and a note of the number of connections in the base.

It looks as though it is probably a rectifier.

This looks like an early  thermionic diode. A development of the Edison Effect and Flemings valve. It was probably used in place of a cat's whisker for a crystal radio. Two terminals at the base of the bulb form the filament heater and would be connected to a lead acid accumulator. The vacuum diode is a forerunner of the semiconductor diode / transistor and was used to demodulate or rectify the radio signals by stripping away one sideband of the received signal. Tuning in a station was accomplished using a wire coil and a variable tuning capacitor wired in parallel. This made the signal audible using headphones as electrons passed in one directon across the gap between the concentric circles at the cente of the bulb. It is probably a bright emitter in order to get enough electrons to energise  the headphones. More modern dull red filaments came later when thoriated cathodes could generate enough electrons at a lower temperature. The anode connection is taken through the wall of the glass bulb and then to the headphones connected to a high tension battery. The HT battery was made of a number of dry cells wired in series to generate around 90 Volts dc.

It could possibly be a form of the tungsten arc lamp or "Pointolite". The latter is the trade name for the lamp which was manfactured by Ediswan.

Various forms of this exist in which an arc is struck detween two electrodes without recourse to very high voltages to initialise the discharge. In some a moving contact is made by thermal expansion, in others by ionisation from an adjoining filament.

In all cases a "ballast" or series resistance is required to limit the current which is normally fed from some 100 volts d.c.  It seems that this ballast is located in the stem of the lamp  - hence the ventilation holes.The light produced is white approximating to daylight and emanates from a very small area of about two square millimetres and can therefore be readily focussed.  Applications include microscopy and technical photography.

Agreed that more detail would be helpful to ensure that this is correct! How many connections at the base?  Does the stem contail a resistor?

Given the watchmaker connection this is probably a discharge (neon?) tube used in a timing device. It may just be a replacement tube and the rest of the equipment is missing. The way that it could be used is that the watch to be timed is placed next to a microphone and the sound of the tick is amplified and shaped into a pulse which is used to flash the discharge tube. The flash illuminates an indicator painted on a disk that is rotating at a precise speed. As the timing on the watch is adjusted the indicator will move forwards or backwards against graduations around the outside of the rotating disk. If the correct number of ticks per minute for the watch is known the watch can be adjusted with a high degree of accuracy. All pretty hi-tech for the 1930s and it must have been an expensive piece of kit. It could also explain why the spare tube has its own wooden box.

The object appears to have an internal metal tube linked through the envelope to the frame, earth. The metal tube is surrounded along its length by a glass tube. I suspect that the structure supporting the glass envalope is hollow and has a coaxial connector inside through which a cable to a control box connects. I think that it functions as an ionising radiation detector. If so it will probably be filled with a low pressure gas and the gap between the inside tube end and the end cap of the coaxial connector is a space where the voltage fed via the cable, does not quite ionise the low pressure gas. Ionising radiation will cause a detectible change in the conditions.  With a bit of luck.