A Technique for Low‐Angle X‐Ray Diffraction Studies on Expanded Three‐Layer Clays

The solution with the simulator allows for flexible scaling of time and distance as reported for the onedimensional simulator. Figure 2 shows results of the demonstration problem. The influence of varying proportions of the surface area exposed to evaporation is shown. These data indicate relatively little decrease in total evaporation of water from the soil until the proportion of exposed surface was decreased below %. There was a greater difference between the evaporation rate-time curves between % and Vs exposure than between 1 and % exposure.— R. J. HANKS AND S. A. BOWERS, Soil Scientists (Physics), Agricultural Research Service, USDA, Manhattan, Kans.