Last night I bought a digital thermometer/hygrometer. I placed it in my incubator and when the mercury said at was 100, the digital said it was 101.8. I was a bit confused as to how off the mercury could be. What is everyone else's choice to use? After this, I an sticking to the digital. I am now maintained at 100F and I can check the humidity correctly. I may have an early hatch, but not under the right terms. I just hope I didn't cook the little guys too much. Everyone seems to be fine though.