A heavy-current discharge tube

A water-cooled cold-cathode discharge tube of simple construction and assembly is described. It runs on high-voltage (over 1500 V.) D.C. or A.C., and can dissipate 3 kW. for short runs, or half that power indefinitely. It is suitable for use with many different gases, and particularly with hydrogen as a source of an ultra-violet continuum. The tube may be employed in emission and absorption spectroscopy, photochemistry, spectrophotometry, and photographic sensitometry. The chief advantages are simplicity, robustness, portability, and constancy of intensity. Spectrograms are reproduced to facilitate the identification of impurities commonly occurring in spectroscopic work.