INTRODUCTION Modern motor oils are marvels of the chemist's art. They lubricate the automotive engine and protect it from rust. corrosion. wear and harmful deposits. They do all this and more through a wide range of operating conditions - - until their effectiveness is depleted by contamination. The motorist has heard that the new motor oils are better than ever. just as he has heard that the new precision-built automobile engines are more powerful and efficient. Both are true. The new oils have to be better or the new improved engines could not operate without increased wear and other troubles.