The natural moisture content of soil is deter-mined from samples taken in the field and placed in a container, which is then sealed to prevent loss of moisture by evaporation. Natural moisture content determinations are valuable in interpreting information obtained from test borings or pits,

in drawing the soil profile, and in estimating the physical properties of soils encountered in the field.

Generally, 100 g of soil is enough to determine the moisture content of fine-grained soils. Larger samples are required for soils that contain gravel. Normally, moisture content samples are placed in metal dishes (canisters) that have tight-fitting covers; however, any other clean container that can be adequately sealed may be used. When the moisture content test is to be per-formed within 1 day after the sample is

Figure 15-8.-Sealing a container to retain moisture content of a sample.

obtained, sealing of the container is not required. If a longer time interval will elapse between sampling and testing, the containers may be sealed, as shown in figure 15-8.