One must begin with f, and then tune its octave pure. After that tune c′, a fifth from f, and make it completely pure. Then lower it just enough that it still seems good and the ear can tolerate it. From c′, tune its lower octave pure. Then tune its fifth g in the same way, narrowing it to the same degree as the first. Then tune its upper octave pure, which is g′. Tune d′, and then tune this fifth in the same way, narrowing it like the others. Then pause at this point and perform the trial, which is done in this way. Tune b♭, next to c′, to the fifth f′, next to g′, and keep the b♭ a bit high, so that this fifth is tempered [temperée] and is the same as the others. Then play the d′ that you have tuned, which makes the major third against b♭ and the minor third against f′. When this chord is found to be good, everything which has been tuned is good, because the tuning is proven only by the thirds. When they are found to be good throughout, the tuning is correct.

Continue then, and follow the order used at the beginning. Go by octaves and fifths to the last note, and do not tune any fifth after the first trial mentioned above if the third within it does not prove to be good, as you may observe in the example that follows.