` ::When a page is moved from one title to another, it should be done using the ``move`` button that at the top of the page instead of copying the text from one title and pasting it into an article at the other title.  Copy-paste is not appropriate because the history of the article gets separated.  That's what happened in this case when ``chlorination`` was moved to ``water chlolination``.  Since edits were made to the article before and after the copy-paste, the history of edits to the text became located in the history of two separate titles.  Because of techinical limitations of Wikipedia's software the only way of fixing this for an administrator to delete one article, move the other article to the same title, delete it again, and then restore all the edits.     `