http://www.google.com/#q=boiling+point+of+air

The different components of air are going to have different boiling points. You can google on freezing point of oxygen, nitrogen, etc. Of course, before that they will liquefy.

Short answer: you seem to have given him the right info, that it's just not cold enough.

Striving to increase my rate of flow, and fight forum gloopiness. sick