The gyrotheodolite lets you navigate by the turn of the earth

One of the wonderful things about science is that it often accomplishes things that you didn't even think were possible in the service of doing things you would never think to do in the first place. A great example of this is the gyrotheodolite, an instrument that lets you navigate underground, by using the rotation… » 7/22/11 3:15pm 7/22/11 3:15pm