METHOD OF MEASUREMENT AND A CUVETTE

Method and apparatus for the measurement of the properties of a liquid (14) placed in a cuvette (2) by means of radiation (22) and of a detector (12) that receives radiation. The beam of measurement (22) passes substantially in the direction of the vertical axis of the cuvette through a measurement window (16) that is located in the bottom of the cuvette and that has a horizontal inside face. Moreover, a cuvette (2) is used whose walls and/ or bottom is, at the inside face, outside the path of passage of the beam of measurement (22), provided with one or several parts (17) projecting from the substantially vertical walls and/or horizontal bottom of the cuvette and being either separate from the cuvette or made of one piece with the cuvette. According to the invention, the shortening of the path of measurement of the beam of measurement (22) passing through the liquid column, resulting from the rising of the surface of the liquid towards the walls of the cuvette, is compensated for by means of the total volume of the projecting part (17) or parts so that the total volume of the projecting part (17) or parts is substantially equal to the volume of the liquid portion that rises from the horizontal level of the middle portion of the liquid surface towards the walls of the cuvette as a result of the adhesion force between the liquid and the inside face of the cuvette wall and as a result of the reduction in the capillary action of the liquid (14). Procede et appareil de mesure des proprietes d'un liquide (14) place dans une cuvette (2) a l'aide d'une radiation (22) et d'un detecteur (12) qui recoit cette radiation. Le rayon de mesure (22) passe sensiblement dans le sens de l'axe vertical de la cuvette au travers d'une fenetre de mesure (16) qui est situee au fond de la cuvette et possede une face interieure horizontale. De plus, une cuvette (2) est utilisee, dont les parois et/ou le fond sont, au niveau de la face interieure, a l'exterieur du passage du rayon de mesure (22), pourvus d'une ou de plusieurs pieces projetant depuis les parois sensiblement verticales et/ou le fond horizontal de la cuvette, lesquelles sont soit independantes de la cuvette ou solidaires de celle-ci. Selon l'invention, le raccourcissement du chemin de mesure du rayon de mesure (22) passant au travers de la colonne de liquide, resultant de l'elevation de la surface du liquide vers les parois de la cuvette est compense par le volume total de la piece ou des pieces de projection (17) pour