the best way to search on Google

If you're looking for something so specific, WW, you may find a directory search is useful. You can do this from Google (Directory tab), or you can cut out the middle man and go straight to the Open Directory that underlies practically all Search Engine Directories:
http://www.dmoz.org

Having said all that, a quick browse through didn't show up a clear timeline of metal discovery and use.... then again, try this:
http://www.enged.com/students/matcom/matcom46.html