The process of reducing a representative soil sample to a convenient size or of dividing a sam-ple into two or more smaller samples for testing is called QUARTERING. The procedures vary somewhat, depending upon the size of the sample.

To quarter a sample of this size, first mix and pile the sample on a canvas, using a shovel. Place each new shovelful on the top-center of the preceding one so that the soil will be distributed evenly in all directions. Then flatten the sample to a circular layer of approximately uniform thickness. Next, insert a stick or length of pipe under the canvas and then lift it at both ends to divide the sample into two equal parts, as shown in figure 15-22. Remove the stick, leaving a fold in the canvas, and then reinsert it under the sample, but this time, at right angles to the first division. Again, lift the stick. This divides the sample into four parts, as shown in figure 15-23. Discard two diagonally opposite quarters, taking care to clean the fines from the canvas. Then remix the remaining material, taking alternate

shovelful from each quarter. Repeat the quartering process as necessary to reduce the sample to the desired size.