At the moment, this chart is static. Most browsers allow cntrl-+ and cntrl-- for zooming the entire page. I've made a couple of versions of this chart interactive with panning and zooming, as well as including significantly more descendants and information. However, they don't 'play' well with the rest of my site styles. Here're the links to them, but you'll need to use your browser's back button to return. 150-Year Timeline and 200-Year Timeline. You may have to wait a little bit for the controls to load and work. Ultimately, the nodes will be clickable too.