PEACTICE 2 

 Determination of Hygroscopic Moisture. 



Use air-dried soils from Practice 1. Mark and weigh the neces- 

 sary number of crucibles to run duplicates of each stratum. Place 

 about 10 grams of air-dried soil in each crucible and weigh. It is best 

 to weigh all of the duplicate samples out at the same time so as to 

 get them under the same conditions as to moisture. The hygroscopic 

 moisture of a soil varies with the relative humidity and temperature 

 of the atmosphere. Heat in an oven at about 100° C. for at least five 

 hours. Cool in a desiccator and weigh rapidly to prevent absorption 

 of moisture from the air. The loss of weight is the hygroscopic mois- 

 ture. 



Express in tabular form the loss in grams and in percent of the 

 water-free soil. Also the total moisture of the samples in percent of 

 water-free soil. 



