BITTERCREEK CAVERN

A Word About Your Cave

Welcome, folks, and thank you for stopping! While you're waiting on your order, here is a little about what you're going to walk through in a few minutes. The cave stays 57°F every day of the year, and I want to tell you why, because people ask me twenty times a day and the answer is not magic. 57° is the average yearly air temperature of the hill sitting on top of it. That's all it is. It is a climate reading. If you moved this hill to Iowa the cave would be 49° and if you moved it to Texarkana it would be 65°.

The humidity runs 97 to 99 percent down there all year long, which is wonderful for the formations and murder on electrical equipment. We have replaced the amplifier in the Cathedral twice in six years and we have quit trying — your guide talks with his own voice and he will be glad to repeat anything, so speak up if you're in the back.

Here is the thing I am proudest of and I will say it again further down this mat because I want you to see it: in 1983 we pulled every fixture back off the rock and re-aimed it at an angle, and the green is gone off the Cathedral wall. That green was lampenflora — algae and moss and cyanobacteria that will colonize any wet surface inside about a metre of a light bulb. It rides in on shoes. It goes green, then it goes black, and it stains. We bleach-wash on a four-week rotation and it is the single biggest maintenance item in this building, bigger than the roof. The new lamps look badly aimed to a lot of people. They are aimed correctly. We are down to 4,300 watts of incandescent on the whole route and the wall is clean.

Folks always want to know why we make groups wait when the cave "looks empty." The interval is not set by how long the tour takes. It is set by the narrowest place two groups can get past each other, and here that is a 31-inch gap at the top of the Long Stairs. That's the whole answer. 22 minutes, every time, and a guide who hurries his people only builds a pile-up at the stairs and everybody stands in the dark for nothing.

One more and then go eat: every person breathes out about 40 grams of carbon dioxide an hour. Down there it dissolves right into the water film on the rock and makes a weak acid, and that acid takes calcite back off. That is why the popcorn along the handrail at chest and nose height is dull and the same popcorn eight feet over your head is bright. It isn't dirt and nobody did anything wrong. It tracks attendance and nothing else. Ask your guide to shine his light straight up at Stop 5 and you will see both at once.