Abstract
Whereas our understanding of the role and mechanism of wall slip has improved substantially over the last decade or two, it is still common to see papers on disperse systems appear wherein scant details of the measurement methods are given and wherein no mention of the possibility (probability?) of slip is made. It is argued that there is a need to raise awareness. It takes experience, judgement and skill to make meaningful measurements on disperse systems and it is suspected that the nature of the experimental challenge is under-estimated grossly by too many workers even now.Comment: 10 pages, 2 figure