88 



LABORATORY EXERCISES 



a. Prepare a bottle and a fruit jar as shown in Fig. 31, this 

 manual. One way to break off the bottom of the bottle is to 

 drop a metal rod, such as a solid metal curtain rod or a straight 

 poker, through the mouth of the bottle. An- 

 other way is to hold the bottle horizontal and 

 rotate it over a small, but hot, Bunsen flame, 

 so that it will be heated in a circle parallel to 

 the bottom. Then plunge the bottle into cold 

 water; the bottom will usually break off. Close 

 the mouth of the bottle by tying a piece of 

 muslin over it. 



b. Tie a string tightly around the bottle, 

 about 5 cm. (2 in.) from the broken end. This 

 serves as a mark. Fill the bottle to the mark 

 with small gravel. Shake the material, and 

 ( j) press it down, but do not make it too compact. 



Then set the bottle in the fruit jar. 



Pour upon the gravel just a cupful of water. 

 Do not add the water all at once, but pour it 

 upon the upper surface just as fast as the 

 gravel can absorb it. Note the time when 

 you add the first water; then find out just how long it takes 

 for the water to begin to drip from the mouth of the bottle. 



c. Empty out the gravel, and fill the bottle to the same mark 

 with fine sand. Add the cupful of water as before, and take the 

 time. 



d. Repeat the experiment of b with loam; then with clay. 

 Give all the results? What causes the difference in results? 



Which soil allows water to pass through it most rapidly? 

 Which least rapidly? Which soil would be the most likely to 

 have water standing on it after a rain? Which would be the 

 least likely? 



FIG. 31 



