 The last "Septenarius" tuning was not conceived in terms of fractions of a comma, despite some modern authors' attempts to approximate it by some such method.Instead, Werckmeister gave the string lengths on the monochord directly, and from that calculated how each fifth ought to be tempered.This tuning uses mostly pure (perfect) fifths, as in Pythagorean tuning, but each of the fifths C-G, G-D, D-A and B-F is made smaller, i.e.