Need help adding zoom functionality to Wordpress site

Hi

I have a website (Lascelleshistory.com) and wish to improve the zoom functionality for the timeline page?

While I can go across the timeline on my iPad, I can't zoom in on the timeline itself which becomes blurred.

I don't have the budget for a super whizzy timeline at the moment though will consider this soon. In the short term I need to make the timeline accessible as possible on various computers and devices.

Any other suggestions on how to improve the site will be gladly considered.

Thanks