Francisco de Salinas, De musica libri septem (Salamanca, 1577)

The Salamanca professor of music who measured tuning instead of arguing about it. His 1577 folio sets out three temperaments of keyboard instruments as exact fractions of the comma, judges the third — the one that leaves the major third in its true form — easier to understand and better suited to instruments, compares two of them by dividing the comma into twenty-eight parts, and reports tuning an organ half tempered and half pure so that the difference could be settled by ear.