The principle of homology has been studied in its relation to high-molecular-weight aliphatic sulfur and nitrogen compounds and has been found to apply in the cases of long-chained amine salts and amides of the normal carboxylic acids, with long-chained pyrrole derivatives, and with long-chained sulfides, sulfoxides and sulfones. Each of these compounds is formed by reactions similar to those used in preparing lower-molecular-weight homologs and have regular variations in physical properties;The use of long-chained amine salts has been suggested as derivatives for the identification of carboxylic acids. Sulfoxides and sulfones are indicated as the logical derivatives for long-chained thio ethers;Limitations in the application of the homolog...