There has been a great advancement in recent years in the technique and production of suitable fuels for both aircraft and automobile engines and the author hopes that a few notes on the fuel problem with particular reference to aircraft work may be of help to those engaged on aero engine design and operation.

In the author's opinion it is somewhat surprising that, with the information and data at present available on the subject of fuels, greater use is not made of this when considering the design and operation of an aero engine.