Comparative efficiencies of size analysis by hydrometer and pipette methods

A large sample of silt and clay was divided into nine sub-samples with concentrations increasing from 3 g/l to 25 g/1. These sub-samples were first subjected to the hydrometer analysis after which they were shaken and re-analyzed by the pipette method. The results of the two analyses were then compared. Within a moderate range of silt and clay concentration (6 to 24 g/l), the analyses gave similar esults for the 5, ~ through 94 ~ 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 over-all results