An interesting essay, but it will take some study.

Note that a link at the right side allows you to open the document as a pdf, which you can save for later study. (Don't forget to rename it when you save, as the default name is a "dummy.")

The pdf appears to have a significantly different layout than the html document, with larger pictures more clearly separated to show the association with the text.

In the html - from which you can select and copy to paste into your word processor - the pictures are "small" placemarkers that don't copy. If you right click to save the pictures, you only get what's shown in the document; but you can click on each picture to open an enlarged view (in a new popup window) with significantly more information than shown in the small ones. If you don't look at the large pics you'll miss lots of the fun.

Two of the enlarged picture pages will likely need a landscape orientation of your page to avoid clipping if you paste them into your WP, but the others fit may clip if not pasted to portrait (on US letter size pages).

There's a reference to the early work by Helmholtz, in the discussion of the effects of vocal cavity contributions to tone - something that Helmholtz wasn't really able to believe in with his more primitive instrumentation, so it's nice to see that "modern" researchers have finally figured out what all the players have known for centuries.

An informative piece, although it could do with a few equations for specificity.

John