Not a Williams tube, but similar in principle.

On a CRT with storage for oscilloscopes or computer monitors, you looked at the stored image, which is why they were called "Direct-view bistable storage tubes".

On the Williams tubes, the processor read back the data stored in the tube, i.e. the stored image was used by the CPU, not by humans, so Williams tubes had no need to contain fluorescent screens. On a viewing tube, there was usually no need to implement a read back method, but only means for writing and erasing.

Both the Williams tubes and the direct-view storage tubes were derived from the iconoscope tubes used before WWII in the early television cameras, according to a proposal made in the famous von Neumann report. In iconoscope tubes, illumination caused by an external image projected on the tube face created an electric charge distribution inside the tube, which was read electronically, generating thus a video signal, so it was the inverse of a direct-view tube, where an electric charge distribution is written inside the tube, where it controls the fluorescence of the screen, creating an image that can be viewed outside. Both iconoscope tubes and direct-view storage tubes differ from simple CRTs by having inside an insulating or semiconducting surface on which a distribution of electric charge can be stored.

The Williams tubes were a form of DRAM. An even earlier kind of DRAM had been used in the Atanasoff-Berry computer, where it was implemented with discrete capacitors and John Atanasoff had been the first who proposed to make a computer memory based on storing electric charge and refreshing it periodically, to prevent discharging.

I have an artifact that looks like 2 Williams tube fused together at the ends. No idea what it is.