But Hippias demurs&colon; he did not touch an obolus there. The ferryman of that river, Kharon, required a coin from the deceased as an obolus. The apothecaries' system also reckoned the obol or obolus as ounce or scruple. He demanded an obolus (coin) to ferry dead souls across the River Styx. The obol or obolus was also a measurement of Greek, Roman, and apothecaries' weight.