The pattern is taught only by Master Engineering Trainers.
Patch changes
Patch 3.2.0 (04-Aug-2009):[Mote Extractor] now has innate tracking for gas clouds while it is in your inventory. Tracking of gas clouds has been removed from goggles.
Hotfix (2009-05-14): "We recently made some changes to items that grant stealth detection. We felt these items provided a necessary advantage in competitive PVP and forced players to use lower level equipment even when more powerful items were available to them.