Does a pencil lead emit light if it is connected to a battery and electricity is passed though it?

A .5mm mechanical pencil lead WILL emit light when enough
electrical current is passed through it. I, persoanlly, have tried 5-7 C batteries and it works
just fine. It burns quickly and the longer you leave the connection running the brighter it gets,
until it burns out, severing the circuit. I have also used a .9mm mechanical pencil lead and
10-12 C batteries. The .9mm mechanical pencil lead became red hot and glowed, but never became
hot enough to emit a white
light. 

Thanks,

Jeff
Stephens

Senior Vice President - Phi Theta Kappa AZM