A recording rapid sediment analyzer has been developed at the Woods Hole Oceanographic Institution from the method and technique described by Appel. The system measures pressure changes included in a column of water by sediment settling through a measured distance. Mechanical analysis of sediment samples whose sizes are between coarse silts and fine gravels can be made. The authors estimate that one operator could complete curves for a maximum of 150 sand samples in a day. Reproducibility of results is excellent. In some of the tests there was no variation of the standard deviation around an average particle diameter, at least to the fourth decimal place. A comparison of mechanical analysis by sieving and settling is given, and a method for determining shape is described.