The investigators do not preclude the possibility that there could be designed and built a water injection device that would operate under the conditions which were imposed on the Briggs' Vapor Jet for the purpose of this investigation. If, however, such a device be built, it is felt that it must be subject to controls of many kinds based on all the variables that affect the highly critical vapor injection problem. The complex nature of such a device makes it highly unlikely that it could find commercial use in the private automobile field. Water injection itself is apparently not more than just barely effective at the compression ratios now being used in passenger car engines. That, considered from both the viewpoint of increasing; the engine's power and performance and from the standpoint of economy, is largely responsible for the ineffectiveness of this Jet. The fact that this device can be mounted on any stock model car with a minimum of work, and that it will produce some results from an economic standpoint may justify its installation in cases where its effect on over-all engine operation and power are not too important. / M.S.