THC 2003.902.119 T. Hignett Control Instruments of the Blast Furnace photo about 2 years 0 THC 2003.902.021 E. H. Johnston Ozone Production photo about 2 years 0 THC 2003.902.019 E. C. White Apparatus for Analysis photo about 2 years 0 THC 2003.902.020 J. F. Shultz Investigation of Phosphine photo about 2 years 0