The equiptment is already set up when we arrive in lab. The procedure requires a spectrometer, tubes of various gasses, and an electrical current supply. Our awesome and amazing TA Devon decides to uncalibrate the apparatus so that we can learn how to properly calibrate. We begin calibration by turning off the lights in the room and running a current through the gas tubes, producing light. We aim the slit of the spectrometer at the tube. We adjust the brass knob on the spectrometer until it coincides with a known value of a specific line of mercury. We unscrew the prism from its base and pivot it until we see spectral lines in the eyepeice, then adjust it until the cross hairs line up with the spectral line with the same value as the brass knob. We then tighten down the prism, our spectrometer is now calibrated. Getting this calibration just right took the entire first day.