How to use Google Books?

How is Google Books able to recognize that the same person can SSH tunnel through multiple servers at once?

• So I wanted to read this new book Gifts of the Crow and wanted to read several chapters out of it. After I read chapter 3 and ran into the page limit for Google Books, I then SSH tunneled into http://icicle.atmos.uw.edu and was able to read through most of chapter 4 before hitting the limit. Then I SSH tunneled into http://astrolab09.astro.washington.edu and I *still* had hit the page limit despite being logged out of Google (apparently, whether you're logged in or out of Google doesn't matter). So... How was Google Books able to recognize that the same person SSH tunneled through multiple servers at once? (also, it makes me hit the page limit even when I use proxies like vtunnel to access the book. How does it recognize that I'm behind a proxy?)

• Answer:

  Same PC?  Try clearing your web cache & cookies.