1. A cooperative organization participated in by the Bureaus of Chemistry and Soils and Plant Industry of the U. S. Department of Agriculture and the Agricultural Experiment Stations of the North Central States of Illinois, Indiana, Iowa, Kansas, Michigan, Minnesota, Missouri, Nebraska, North Dakota, Ohio, South Dakota, and Wisconsin.
2. Throughout this communication the terms “diene number” and “maleic anhydride value” are used as the original authors indicated, while “diene value” is used without reference to the method of determination.