31.6 is the sq. rt. of 1000, approximately. Power is proportional to the
sq.of volts or amps. So, if you want to represent watts as a function of
transmission line volts and, or transmission line amps, you can print
the scale of a linear meter so that it advances as the sq. rt. of the
current. That is, current increases to 141.4% of its previous value, and
the watts indication doubles. That`s because 1.414X the volts multiplied
by 1.414X the amps equals 2X the watts.
Richard, That is exactly what I was trying to say, one can measure the
power absorbed by a known resistive load by sampling V or I, rectify, scale and
display on a log scale meter, or is it square law? Whichever one it is, it
ain't linear.

73 Gary N4AST