LABORATORY PRACTICE 313 



after the addition of each measured quantity by allowing the weight 

 from the compaction machine (see Experiment No. 8) to drop twice 

 from the 1 2-inch mark. 



In a similar way, fill a second and a third tube with clay 

 and loam respectively ; immerse the lower ends of the tubes in 

 a cylinder of water and support the tubes, as shown in the illus- 

 tration. Measure each day for one week the height to which the 

 water rises in the soils. If desired, three more tubes filled loosely 

 with the soils may be added, and the influence of compaction 

 upon the capillary rise of water in the soils noted. 



Experiment No. 5 



Influence of Manure and Shallow Surface Cultivation upon th? 

 Moisture Content and Temperature of Soils 



Weigh and fill four boxes, each a foot square and a foot deep, 

 as follows : one with air-dried sand, one with clay, one with loam, and 

 one with sand containing 5 per cent of fine dry manure. Deter- 

 mine the hydroscopic moisture of each sample. Weigh the boxes 

 after adding the soils which should be moderately compacted. To 

 each add the same amount of water slowly from a sprinkling pot, 

 carefully measuring the water used. The soil should be well mois- 

 tened, but not supersaturated. Each box is to receive shallow sur- 

 face cultivation, using for the purpose a gardener's small tool. Leave 

 the boxes exposed to the sun or in a moderately warm room. At the 

 end of one or two days take a sample of soil from the center of 

 each box at a depth of 4 to 8 inches and determine the moisture 

 content as directed in Experiment No. i. Note the differences in 

 moisture content. Weigh the boxes. Take the temperature of the 

 soil in each box. 



Experiment No. 6 

 Weight of Soils 



Determine the cubic contents of a box about 4 inches square. 

 Weigh the box. Determine its weight when filled, not compacted, 



