Where to position CO2 lamp?

Okay, so just got my hands on a bunch of disposable CO2 lamps with about 100 hours each. I was wondering where to position them?

what on earth is a co2 lamp??

yeah, what he said.I even google that shit and have no clue :/

whatever it is, hang it from the ceiling!
CO2 falls because it is heavier than air at certain tempuratures. It also has a natural flux between temp gradients in the grow area so when its hot the CO2 rises and when its cold the CO2 falls

BUMPfast forward to now!) I've invented the co2 lamp, where the fuck do I put this thing?