A system for the automated dilution and delivery of a plurality of mixtures of diluent and liquid samples respectively disposed in an equal plurality of congruent sample containers to a particle counter, said congruent sample containers having an upwardly facing open mouth, the system comprising: a. a container positioning member for receiving and retaining said congruent sample containers in an array with a respective unknown volume of liquid sample having been poured into each said sample container, wherein said unknown volume of each liquid sample is less than a pre-determined threshold volume that is less than the total volume of the respective sample container; b. an automated diluent pumping mechanism having a diluent ingress port in fluid communication with a diluent source and a diluent egress port positionable in programmed sequence over the open mouth of each of said congruent sample containers retained in said array, for drawing a respective volume of a suitable diluent from said diluent source and for introducing said drawn volume of said diluent through said open mouth of each said sample container for mixing with the respective unknown volume of said liquid sample within each said sample container to together form a mixture of said liquid sample and said diluent, wherein the volume of said mixture is substantially equal to said pre-determined threshold volume; c. a mixer for agitating said mixture of liquid sample and diluent in said sample containers; d. an automated mixture pumping mechanism having a mixture ingress port positionable in said programmed sequence over the mouth of each of said congruent sample containers retained in said array so as to be in fluid communication with said mixture of liquid sample and diluent in each said sample container, and a mixture egress port in fluid communication with said particle counter, for sequentially drawing a respective volume of mixture of liquid sample and diluent from said sample containers and for delivering the respective drawn volume of mixture of said liquid sample and said diluent to said particle counter, wherein said mixture ingress port, said diluent egress port and said mixer are mounted on a sampling head. a. a container positioning member for receiving and retaining said congruent sample containers in an array with a respective unknown volume of liquid sample having been poured into each said sample container, wherein said unknown volume of each liquid sample is less than a pre-determined threshold volume that is less than the total volume of the respective sample container; b. an automated diluent pumping mechanism having a diluent ingress port in fluid communication with a diluent source and a diluent egress port positionable in programmed sequence over the open mouth of each of said congruent sample containers retained in said array, for drawing a respective volume of a suitable diluent from said diluent source and for introducing said drawn volume of said diluent through said open mouth of each said sample container for mixing with the respective unknown volume of said liquid sample within each said sample container to together form a mixture of said liquid sample and said diluent, wherein the volume of said mixture is substantially equal to said pre-determined threshold volume; c. a mixer for agitating said mixture of liquid sample and diluent in said sample containers; d. an automated mixture pumping mechanism having a mixture ingress port positionable in said programmed sequence over the mouth of each of said congruent sample containers retained in said array so as to be in fluid communication with said mixture of liquid sample and diluent in each said sample container, and a mixture egress port in fluid communication with said particle counter, for sequentially drawing a respective volume of mixture of liquid sample and diluent from said sample containers and for delivering the respective drawn volume of mixture of said liquid sample and said diluent to said particle counter,