Old School "Comic Book" X-Ray Glasses

Time for very random thoughts... All of a sudden I'm struck with a long supressed curiosity about those X-Ray glasses that were always advertised in Comic Books and sold in novelty shops. I never got a pair and I briefly donned a pair owned by a friend in elementary school.

Since I'm sure I'm not the only one who has this recurring curiosity, here's a web page that I found that supposedly explains how those X-Ray glasses worked.

http://www.blamepro.com/how/how4.htm