Various compounds were investigated to determine their pro knock activity by adding them to the air intake of, or to the gasoline used by and Ethyl 30 B Knock Testing Engine. The best compound tested was arsenic tri chloride which requires 5.8 parts per million of air by volume to cause a decrease of ten octane units in a leaded gasoline. It was found that the best knock inducer elements were in order of effectiveness: arsenic, antimony and phosphorous. Mercury, vanadium and chromium were also found to be effective. Among the radicals the halogens were most effective, the order being bromine, chlorine, iodine and fluorine. Effectiveness of halogens appeared to be enhanced by the presence of a nitro and methyl groups. [...] The dynamic sorption of butane and amnonia on charcoal was studied using an apparatus which followed the sorption by weight as a function of time and permitted measurement of temperature rise and analysis of the effluent gas stream over a wide range of sorbate concentrations and flowrates. The data were applied to the theories of Danby et al and of Mecklenberg and were found to be essentially in good agreement