Marin Mersenne‘s “Harmonie Universelle” is an encyclopedic work on the musical theory and instruments of the 17th century.

Being a mathematician, musician and theologian Mersenne took a more scientific route towards explaining the musical theory of the day, the various systems of temperament, etc.

In Mersenne’s time the West had not yet settled on equal temperament as the standard for intonation. Keyboard instruments  presented a challenge and often had more than 12 keys per octave to accommodate this:

Mersenne explains the acoustical principals behind instruments of his day, theories on selecting string gauges and other specialized information relevant to musicians and instrument makers.

Books I am drawn too are often out of print, rare, expensive or generally hard to find. I was delighted to find a version of Harmonie Universelle translated into English through my local library system.

There is no ISBN but here is the relevant information should you want to find this book:

Marin Mersenne “Harmonie Universelle – The Books On Instruments” translated by Roger E. Chapman – published by Martinus Nijhoff/The Hague/1957