This paper deals briefly with the methods and results from three separate investigations that are in progress as to the quantity of rain‐water that percolates downward to the water‐table in the localities where it falls.
1. Workers in the Department of Agriculture, under the direction of W. W. McLaughlin and in cooperation with the California State Department of Public Works, have used several related methods to intercept and measure the rainfall‐penetration. H. F. Blaney and C. A. Taylor have conducted these tests near Los Angeles. A report covering this work, with H. F. Blaney, C. A. Taylor, and A. A. Young as co‐authors, will be published in the near future as a bulletin by the State of California, Department of Public Works, Division of Water Resources. Rough sketches of some of the apparatus used are shown in Figures 1 and 2.