Interfacial, DU-NOUY, ring method, ASTM approved. Tensiometer gives precise readings of both surface and interfacial tensions by the ring method to values reproducible to within 0.05 dyne/cm. This instrument is specified for determining interfacial tension of oil against water by the ring method in ASTM Method D-971 and solutions of surface-active agents in ASTM Method D-1331. It is also specified for testing synthetic rubber latices in ASTM Method D-1417 and determining the surface tension of industrial water and industrial waste water in ATM Method D-1590.**The graduated dial reads in both directions from zero and a double vernier is provided. The two scales and corresponding verniers have graduations and figures of different colors to indicate whether the measured force is upward or downward. The clamped platform which supports the liquid sample provides coarse adjustment; fine adjustment is obtained by a micrometer screw. At a given height, the platform may be swung away from the ring by a collar on the rod. The 6cm ring and its supporting frame are made of platinum-iridium wire and welded. Completely assembled with T1240-1 torsion wire; T1320 platinum-iridium ring, 6cm; metal case and directions. Shipping weight, 27 lbs.