PRACTICE XXVI 



A STUDY OF THE CAPILLARY POWER OF DIFFERENT 



GRADES OF SAND 



A class exercise to be arranged by the instructor. 



Place cheesecloth over the end of 1-inch glass tubes 1 J- meters 

 or 5 feet in length, as directed in Practice XXV. Fill tubes to 

 a depth of from 30 to 36 inches, and compact by dropping four 

 times a distance of 4 inches on a book with covers removed. 

 Great care must be taken to have compaction uniform. 



Tube No. 1 is tilled with white sand passing through a sieve 

 with 100 meshes to the inch, but not through 120 meshes. 



Tube No. 2 with sand passing an 80-mesh sieve, but not a 

 100-mesh. 



Tube No. 3 with sand passing a 60-mesh, but not an 80-mesh. 



Tube No. 4 w^ith sand passing a 40-mesh, but not a 60-mesh. 



Tube No. 5 with sand passing a 20-mesh, but not a 40-mesh. 



Place the tubes in the supporting frames in such a manner 

 that the ends shall dip one-half inch beneath the surface of the 

 water contained in the tray. The experiment is now ready for 

 observation, and the data to be obtained at each reading is the 

 total height to which the water has risen. The readings are to 

 be taken as nearly as possible at the intervals stated below and 

 tabulated. 



A large class may be divided into groups. Each group will be 

 assigned a definite time to take readings and will record same on 

 a data sheet. Readings should be taken at 10-minute intervals 

 after the water is turned on. Each student will secure all the 

 data and plot curves to hand in with data sheet. 



What relation between size of particles and rapidity of rise of 

 water ? between size of particles and height to which the water 

 ultimately rises ? 



References. 



"Soils," Lyon and Fippin, pp. 169-189. 



" The Soil," Hall, pp. 71-75 and 97-99. 



" Physical Properties of Soil," Warington, p. 92. 



" The Soil," King, pp. 136-142, 173-178, and 19-1-195. 



" Soils," Hilgard, pp. 202-207. 



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