Precision DuNouy Tensiometer, ring method, ASTM. Tensiometer gives precise readings of upward interfacial and surface tensions by the ring method to values reproducible within 0.05 dyne/cm. This instrument is specified for determining interfacial tension of oil against water by the ring method of ASTM Method D971 and solutions of surface-active agents in ASTM Method D1331. It is also specified for determining the surface tension of industrial water and industrial waste water in ASTM Method D1590. The ring and support stirrup are made of platinum-iridium wire with welded joints. The ring is supported on the end of a light arm with an adjustable hook. This allows standardizing the instrument for direct readings in dynes/cm. The essential parts are mounted on a tripod support with leveling screws. The tripod and supports are finished in gray hammertone. Use T1220-1 Torsion Wires only when 4 cm. ring is utilized. Use T1240-1 only when the T1280 6 cm. ring is utilized. Monel wire is recommended for use where high resistance to corrosion is desirable. Completely assembled with T1240-1 Torsion Wire, T1280 platinum-iridium ring (6 cm); with metal case and directions. Shipping weight: 27 lbs.