Your privacy is important to the library, which is why we have measures in place to protect confidentiality. All the library's public computers are designed to clean patron data every single time a patron logs out of the computer. All browsing history is erased.
Also, if you have saved anything to the hard drive of a library computer, it will be erased when you log out. With the cleaning that takes place during log out, the computer is completely restored to its original state.
Unfortunately, you can't see this in action by clicking tools --> delete browser history. To ensure this security measure works, the library asks you to log out. If you're curious about it, you can then log back in to see that the security is in place. Once you log out and then you (or anyone else) logs in, you will not find any browser history.