He is noted for the studies of oxidation for which he developed a method involving high temperature digestion in a sealed tube. Heavy wall sealed tubes, as used for digestion or thermolysis, are referred to as "Carius tubes". He also wrote a textbook on polybasic acids.
He is recognized for his research on oxidation, which he pioneered through a technique involving high-temperature digestion in a sealed container. Heavy-walled sealed containers, used for digestion or thermal decomposition, are called "Carius tubes". He also authored a textbook on polybasic acids.