Cookies set location

On my old 1.5 version of WordPress I had reset the cookies timeout in functions.php so that they would timeout in 10 minutes. The cookies setting and timeout evidently have been moved out of this file. Can anyone tell me where to find them so I can adjust the timeout again?

I really wish cookie timeout would be made a settable option from a menu. That would be helpful.

Why do I want to adjust this value. So computers in public locations won’t stay logged on indefinitely if the user forgets to log out.