Provides precise reading of both surface and interfacial tensions by the ring method to values reproducible within ±0.05 dyne/cm.

• The instrument is specified for determining interfacial tension of oil against water by the ring method in ASTM Method D971 and solutions of surface-active agents in ASTM Method D1331
• It is also specified for testing synthetic rubber lattices in ASTM Method D1417 and determining the surface tension of industrial water and industrial wastewater in ASTM Method D1590

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 6 cm (2³/₈") platinum-iridium ring has stirrup with parallel sides that are 25 mm (1") high to permit the ring to be used in upward and downward interfacial measurements, as well as surface tension measurements. Packed in a protective container, unit has a mean circumference of approximately 6 cm (2³/₈") indicated to three significant figures and is marked with the ratio of the radii of the ring and cross section of the wire.