The lead salts of the acids of this series are much more soluble in ether, and the lithium salts more soluble in alcohol than those of the stearic series, upon both of which properties processes have been based for the separation of the solid from the liquid fatty acids.
III. Linolic Series:—
| Acid. | Formula. | Melting Point, °C. | Found in |
| Elæomargaric | C16H29COOH | ... | Chinese-wood oil. |
| Elæostearic | C16H29COOH | 71 | Chinese-wood oil. |
| Linolic | C17H31COOH | Fluid | Linseed, cotton-seed and maize oils. |
| Tariric | C17H31COOH | 50.5 | Tariri-seed oil. |
| Telfairic | C17H31COOH | Fluid | Telfairia oil. |
These acids readily combine with bromine, iodine, or oxygen. They are unaffected by nitrous acid, and their lead salts are soluble in ether.
IV. Linolenic Series:—
| Acid. | Formula. | Found in |
| Linolenic | C17H29COOH | Linseed oil. |
| Isolinolenic | C17H29COOH | Linseed oil. |
| Jecoric | C17H29COOH | Cod-liver and marine animal oils. |
These acids are similar in properties to those of Class III., but combine with six atoms of bromine or iodine, whereas the latter combine with only four atoms.
V. Ricinoleic Series:—
| Acid. | Formula. | Melting Point, °C. | Found in |
| Ricinoleic | C17H22(OH)COOH | 4-5 | Castor oil. |