[Douglas Greville]

Hello

Purely a curiosity question.

Would anyone have a photo etc of the above device. From a description I have been given, it was a large mechanical computer type device intended for scouts (had to be mounted in a vehicle), that plotted location on a paper chart purely based on direction and speed of travel.
It does not sound like a proper inertial unit, more like something slaved
off a speedo drive shaft?

Thanks
Doug