A large sample of silt and clay was divided into 9 subsamples, with concentrations increasing from 3 g./l. to 25 g./l. These subsamples were first subjected to the hydrometer analysis, after which they were shaken and re-analyzed by the pipette method. The results of the 2 analyses were then compared. Within a moderate range of silt and clay concentration (6 to 24 g./l.), the analyses gave similar results for the 5phi through 9phi size-grades. With concentrations of less than 6 g./l., the pipette analysis was superior; with concentrations greater than 24 g./l., the hydrometer analysis was more efficient. Within the range of concentrations studied, however, the pipette method gave better overall results.