The Spectrum of the Neutral Mercury Atom in the Wave-Length Range from 1 to 2μ

New information on the near infra-red spectrum of mercury has been obtained with a specially constructed thermocouple in connection with an automatic recording spectrograph. Fourteen new lines predicted by the combination principle and eight unclassified lines have been found in this region. Intensity relations for the triplet $1{}_{}{}^3{}_{}{}^{}S_1^{}{}_{}{}^{}-2\mathrm{}{}_{}{}^3{}_{}{}^{}P_{0,1,2}^{}{}_{}{}^{}$, which extends over 2700A, have been found to follow rather closely the summation rule as refined by R. H. Fowler for wide multiplets.