An identical series of interferograms was recorded. The SNR is improved by approximately 2x to between 5000 and 6000:1, and the slope of the lines is also substantially improved. However, the lines are no longer clustered at 100% T. The insulation has caused a slow temperature rise inside the spectrometer which is affecting either or both the pyroelectric detector and beamsplitter efficiencies. The prominent water vapor lines and CO2 bands in this series of spectra were caused by a very slow purge for removing some of laser waste heat.