Further comparisons of grain size distributions determined by electronic particle counting and pipette techniques

Mean grain sizes as determined by electronic particle counting have been reported as coarser than those determined by pipette analysis. This has been attributed to possible particle shape effects, possible coincidence error in particle counting, or an omission of some of the finest fraction from particle counting. Comparison of grain size distribution parameters determined from pipette analyses with parameters calculated from the same raw data but with a fine fraction (>10.6 0) omitted, as in particle counting, shows that the omission accounts for all of the coarsening effect. It also entirely accounts for lower standard deviations produced by particle counting. Differences between moment skewness and kurtosis values derived from the two methods are negligible.