Anybody remember the days of going to the drug store to test the tubes from your ol' television set? Once you found out which ones were bad, you could pick out the proper tubes from the cabinet beneath the tester, buy 'em, and be on your way.
Yep, that was back in the days when VACUUM TUBES were king.
I know some of you are blog-hopping, and don't want to spend long on any one post, but for those of you who have time to linger awhile, here are two videos you might enjoy. It shows the amazing process a Frenchman still uses to build vacuum tubes ... by hand!