Using a Crayon as a Candle in Case of Emergency

I saw a picture of a crayon burning and the caption read that you could burn a crayon for 30 minutes in case of an emergency.... Well I had to know if this was in fact the case... So there you go, Who Knew?!?!?!  So now I will be sure to keep a box of crayons in my emergency readiness kit.  And we always have crayons in the van, so I just love this little trick! I always knew you could make candles out of crayon shavings or melting down crayons and adding a wick, but I never thought to just burn a crayon.