Was fishing under a bridge years ago.A friend had his fathers new propane lantern tied to a string hanging from the bridge.String got hot, lantern dropped in fifty foot of water.We watched as it bubbled and went out of sight still bubbling.My friend was still fretting the loss of his fathers lantern later when the bubbles stopped and the lantern floated right back up close enough to the boat to grab it with the net.Would not believe this if I wasn't there but I was