Surface tension measurements have been made on normal heptylic, pelargonic, capric, and lauric acids above their melting points and on aqueous solutions of heptylic, pelargonic, capric, and undecylic acids, at various concentrations. A modified capillary rise method was employed. The results indicate that the surface does not reach the stable state at once but requires considerable time, being slower for more dilute solutions and longer chain molecules. Evidence is given for the existence of a monolayer of closely packed molecules, with long axes perpendicular to the surface, each molecule occupying an area of approximately 25 Å for heptylic acid.