Fahrenheit He then re-calibrated his scale using the melting point of ice and normal human body temperature (which were at 30 and 90 degrees); he adjusted the scale so that the melting point of ice would be 32 degrees and body temperature 96 degrees, so that 64 intervals would separate the two, allowing him to mark degree lines on his instruments by simply bisecting the interval six times (since 64 is 2 to the sixth power). Fahrenheit observed that water boils at about 212 degrees using this scale. The use of the freezing and boiling points of water as thermometer fixed
Lava River Cave this section of the cave requires visitors to crawl on hands and knees for much of the distance to the cave’s end, and usually takes at least thirty minutes. The air temperature at the mouth of the cave ranges from about 32 degrees to around 45 degrees Fahrenheit (-1 degrees to around 7 degrees Celsius) depending on the time of year. Inside the cave, it is a constant 42 degrees (5.6 degrees Celsius). As a result, the Forest Service strongly recommends that visitors wear a warm jacket while exploring the cave. Lanterns can be rented at the visitor center above