Electrical conductivity procedures are widely preferred for measuring the purity of condensed steam. Because gases such as carbon dioxide and ammonia contribute to the conductivity as do dissolved salts carried over from the boiler, interpretation of conductivity measurements may be somewhat uncertain. A new degasser has been developed which automatically splits a steam sample into two approximately equal streams of condensate, one containing all solid impurities, the other containing all gaseous impurities in the original sample. Heat-exchange elements are combined in a unique way which guarantees that the weight ratio of one stream to the other will remain substantially constant. Both streams pass through conductivity flow cells so the degree of contamination can be measured continuously by conductometric means.