Hmm... As I recall from a science class a loooong time ago, one can make a barometer. I'll have to try some specific instrictions, but I suspect that you could fabricate one from a water container, perhaps a found pop can, and the seep tubing in your PSK.<br><br>Not an essential tool, but could be useful of you're stuck in a long-term survivial situation and you want to track changes in weather.