It would certainly be nice if you had a few controls on there to limit the time-line to specific chunks of time (like last 100 years, a specific time-frame, all, and reset to default [perhaps that is also all]).
It probably wouldn’t hurt to provide an option for users to have a horizontal scroll bar as well, or at least prominently display a message telling people to grab and drag the time-line to move side to side.
Fixed that, take a look.
Do you think that is worded correctly?