Guys, to anyone saying that every mage has always known this, with all due respect, you are idiots. You can't judge other people's intelligence due to what YOU know. That's like saying, "Hey, you gained some weight, would it help if I jogged?" Just because you know or do something doesn't mean it reflects on to everyone else.
"Hey, my friend knows the first 800 digits of pi (not true, just example), YOU should know it too!"
No. Some people don't know it, and it helped them.
Sorry about the rant, but that's my big pet peeve
Anyways, @OP yes, I already knew this, but that's only through my love of spamming instant casts after spells. Good find on your own, and not a repost AFAIK.
Dyslexics... UNTIE!!!! ---- 5 out of 4 people have trouble with fractions
common sense -.-