This paper presents the study of some physical properties of the jet from the headbox, by means of optical signal correlations. In particular, an attempt is made to try to describe the floc distribution in the pulp suspension flows by means of a coherence function. It is also shown that there are similarities between pulp suspension flow in pipes and in thejet from the headbox, as far as the influence of consistency and turbulence on the floc size and distribution is concemed. (Abstractor's note: Of interest to those looking for information on specific details of the modern paper making process.) -- AATA