100818-1229 EST
rattus:
Your post 158 made a good point, which I think is the basis to the original point of this thread. I think Electric-Light had in mind a low frequency of excitation to the load and thus a non-linear load. This is my conclusion from his answer in the poll, and one of his posts.
Your post 161 is certainly possible.
Using quickly available resources, meaning searching via the Internet, or books that I have, I have found it difficult to trace the evolution of certain concepts, and words.
At the time that Edison developed his electrical distributions system, 1878-1879, some if not most theoreticians believed that one should design for maximum power transfer. In other words the source resistance was equal to load resistance, 50% efficiency. Edison realized that for a practical system one needed parallel loads and a low source resistance and high efficiency in the generator. Circa this time they had galvanometers, but no voltmeters or ammeters. They had resistance boxes and bridge circuits. They apparently did not conceive of the idea at that time to calibrate the galvanometer deflection to use it for a voltmeter, nor the idea to make a low resistance shunt to measure current. Thus, very awkward means were used to get voltage and current information. However, a very useful technique of putting a thermometer in the rotor or field coil to obtain temperature rise measurements was used.
On the internet I found bits and pieces of information on the evolution of measurement from compass deflection to the Weston-D'Arsonval meter movement. But not a very clear trail.
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