Method and apparatus for monitoring and controlling the charging operation of an elongated measuring chamber

Apparatus for analyzing liquid specimen material, comprising wall means defining an elongated measuring chamber, means for introducing liquid specimen material into said chamber, a plurality of selective measuring electrodes extending through said wall means for contacting the specimen material and sensitive to predetermined characteristic of the specimen material for providing output measurements suitable for analysis, three spaced electrically conducting contact devices extending through said wall means for also contacting the specimen material, the first contact device being located at the input end of said chamber, the second contact device being located downstream of one of said electrodes and upstream of the other electrodes, and the third contact device being located at the output end of said chamber, and inluding a monitoring device connected to said three contact devices for measuring the electrical resistance through the specimen material between respective contact devices and generating corresponding signals, said means for introducing the specimen material being responsive to said signals for controlling the flow of the specimen material in said chamber.