nephelometern.

1884 Amer. Meteorol. Jrnl. 1 4 It bears about the same relations to the nephelometer which we should have, that the sun-dial bears to the clock.

1959 R. E. Huschke Gloss. Meteorol. 388 Nephometer (also called nephelometer), a general term for instruments designed to measure the amount of cloudiness.

1895 T. W. Richards in Proc. Amer. Acad. Arts & Sci. 1894–5 30 385 Since the opalescence was so faint that one could only with difficulty see it at all under ordinary conditions, a piece of apparatus, which may be named a ‘nephelometer’ (νεϕελη, a cloud), was devised for detecting it.

1906 Medicine (Detroit) 12 249/1 It occurred to us that uniformity in the number of bacteria..could be secured..by some means of measuring and standardizing the turbidity of the fluid containing them. We therefore devised a simple instrument, for which we suggest the name nephelometer.., by which it became easy to secure any desired degree of turbidity.

1936 F. D. Snell & C. T. Snell Colorimetric Methods of Anal. viii. 91 In the usual nephelometer the opaque tubes with clear glass bottoms used in colorimetry have been replaced with clear glass tubes with opaque bottoms.

1974 Times-Herald-Record (Middletown, N.Y.) 12 May (caption) Researchers set up a light scattering instrument called an integrating nephelometer atop Mount Beacon. The tests were part of an air-pollution study.

1994 Ecol. Applic. 4 693/2 The visibility monitoring currently includes a 35 mm camera, nephelometer, and particle sampler.