Note G — PART III THE PHYSICAL SCIENCES

For the sake of the layman it must be observed that those "quantities" are not energy magnitudes but factors of the electrical and magnetic energies. Energy itself in its various forms is an exclusively positive magnitude, and the result of the additions of their various amounts is always the sum, never the difference, of their numerical values. By the negative sign is understood the energy expended in contradistinction to the energy received. It is therefore nothing more than the indication of a mathematical operation.