Humboldt State University ® Department of Chemistry

Robert A. Paselk Scientific Instrument Museum

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Interfacial Tensiometer, Cenco-DuNouy

Central Scientific Company, Chicago

Humboldt State College, 1963

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Used for the precise measurement of both interfacial and surface tensions, this instrument incorporates the torsion balance ring method published by du Nouy in 1925. As seen in this image, the instrument has the ring in place dipping into a dish that would contain the sample for measurement. In operation the ring is first submerged in the liquid, them brought to the point where ring is just at the surface using the screw control beneath the sample table with the index (detail image) at about zero. One then lowers the table while keeping index at zero by turning the knob on the right which increases the tension via a torsion wire. The tension is indicated on the front dial at teh point where the ring breaks free of the surface.

Some contemporary/early descriptions of the tensiometer and its use are provided below:


The instrument is built around a heavy cast-iron stand. It is described in detail in the Cenco catalog description. The instrument on display is in very good condition, with some light surface corrosion of galvanized(?) parts. The instrument came in its original metal case, and is accompanied by two tensiometer rings in their original containers. One is mounted on the instrument for display. You may view a scan of the catalog description of a similar ring with a hook instead of rod attachment You may view an image of the case exterior, an image of the instrument and accesories in the case, and photo images of the two ring containers, open and closed. The container labels are identical in dates, specifications, and inspector. The ring is seen in the open container (arrow, the lower metal retaining ring is part of the box ).

Use this link to view a scanned copy of the original manual.


From the Analytical/Physical Chemistry Lab - Exhibit Catalog

 HSTC icon
HSTC (1921-34)
HSC 54-73 icon
HSC (1954-1973)
HSC 35-53 icon
HSC (1935-1953)

HSC 1956-72 Instrument Collection

© R. Paselk
Last modified 13 August 2010