Bullock and Browns Unigraph

A portable sender - receiver for engineers working on land based cables An example of Victorian micro-miniaturisation! Linesmen used it to tap into telegraph lines and talk back to the office, whilst still out on repair or maintenance work. It combined a morse key and a sounder in one small device.

Compare the size of the Unigraph with that of the earlier, individual components to see just how much more convenient it must have been for the linemen.