neph·e·lom·e·ter 
(nĕf′ə-lŏmĭ-tər)
(nĕf′ə-lŏmĭ-tər)n.
An apparatus that is used to measure the size and concentration of particles in a liquid by analysis of light scattered by the liquid.
[Greek nephelē, cloud; see nebh- in the Appendix of Indo-European roots + -METER.]
neph′e·lo·metric (-lō-mĕtrĭk) adj.
neph′e·lome·try n.