The reaction of nitrogen trichloride with the unsaturated hydrocarbons, 1-butene, 2-butene and trimethylethylene has been reported in a previous communication, as has also its reaction with the unsaturated ketones, 2 benzalacetophenone and benzalacetone. The reaction has now been studied with ethene, propene, methylpropene, 2-pentene and cyclohexene. There is a wide difference in the reaction rates of these hydrocarbons. ...