Note to Ad Valorem from Unto This Last by John Ruskin

Labour which is entirely good of its kind, that is to say, effective, or efficient, the Greeks called " weighable," or Ancient Greek translated usually "worthy", and because thus substantial and true, they called its price Ancient Greek the "honourable estimate" of it (honorarium): this word being founded on their conception of true labour as a divine thing, to be honoured with the kind of honour given to the gods: whereas the price of false labour, or of that which led away from life, was to be, not honour, but vengeance; for which they reserved another word, attributing the exaction of such price to a peculiar goddess called Tisiphone, the "requiter (or quittance-taker) of death"; a person versed in the highest branches of arithmetic, and punctual in her habits; with whom accounts current have been opened also in modern days.