best format of Handbook of Nature Study for iPad

I found a site that has free online versions of the Handbook of Nature Study.  I’d love to put this on my iPad.  I downloaded the epub version but was dissapointed that the table of contents didn’t work (you know when you can click on a chapter and automatically go to it).  It’s a rather large book to not have a working table of contents.  Did I download the wrong version?  Is there a better one out there?

This is the site I used: http://archive.org/details/handbookofnature002506mbp