I used to do Oceanographic research and we had a piece of equipment called a "shipboard gravimeter" originally built in the 1950s.
It was basically a very sensitive spring in a gyro stabilized platform attached to a bunch of analogue circuitry and was designed to measure the strength of the gravitational field (on a moving ship).
The manual for this equipment was amazing -- it literally taught you everything about the device and how it worked -- from the theory behind it to the purpose and function of each component.
In some sense writing a complete manual was easier to accomplish then than an equivalent manual would be now -- the a to d circuit used in a modern implementation would likely be more complex than the whole 1950s device ... but old manuals really are of a different quality and thoroughness than anything written for a modern audience ...
It was basically a very sensitive spring in a gyro stabilized platform attached to a bunch of analogue circuitry and was designed to measure the strength of the gravitational field (on a moving ship).
The manual for this equipment was amazing -- it literally taught you everything about the device and how it worked -- from the theory behind it to the purpose and function of each component.
In some sense writing a complete manual was easier to accomplish then than an equivalent manual would be now -- the a to d circuit used in a modern implementation would likely be more complex than the whole 1950s device ... but old manuals really are of a different quality and thoroughness than anything written for a modern audience ...