PISTON-RINGS <xref ref-type="fn" rid="FN1">1</xref>

The author believes the piston-ring problem to be an engineering one worthy of serious study and that it should be possible to standardize types and sizes in a way that will go far toward elminating present difficulties.

It is stated that cast iron is the only satisfactory metal suitable for use in the internal-combustion engine and that the foundry offers the greatest opportunity for improvement, in the elimination of poor castings. The superiority of individually cast rings is averred and a formula for their composition is given.

Leakage and oil-pumping are discussed, followed by comment upon the width and form most desirable for piston-rings; and some of the difficulties of their manufacture are enumerated, together with suggested improvements, inclusive of inspection and testing methods.