The desirability of obtaining an even distribution of temperature at the outlet of a ramjet combustor is indicated theoretically. Results of experiments on a particular combustion system over a limited range of conditions using a series of mixers are presented. The results suggest that mixers are desirable for high Mach Number ramjets operating at low overall fuel-air ratios. The material presented in this report is based on the work carried out by M. R. Williams in partial fulfilment of the requirements for the Diploma of the College of Aeronautics, and is essentially a summary of his thesis. The work was part of M.O.S. Research Contract 7/Exptl./720