Crapper (1957) has theoretically predicted that pure capillary waves have profiles that peak downward, which is the reverse of the gravity wave case. This paper confirms Crapper's theory and shows enlarged profiles of capillary waves that were photographed with a high-speed motion picture camera in a small water-wind tunnel. Under the conditions of measurements, the maximum vertical distance between trough and crest for the capillary waves observed was about 0.5 wavelength....