56 AGRICULTURE ON THE PACIFIC SLOPE 



Water takes up (dissolves) nearly every substance 

 that we see in daily life, including air. Even glass, and 

 flint or quartz, are a little dissolved by water, and so of 

 course is soil. 



Put a teacupful of a loam soil into a funnel the neck 

 of which has been stopped with a plug of cotton batting. 

 Put some batting on top of the soil and then pour on ; 

 gently, enough distilled water (see page 58) to wet it, 

 until a few drops come out at the beak of the funnel; 

 these should be clear. Let it stand three or four hours 

 or overnight. Then, while holding a bright tablespoon 

 under the beak of the funnel, pour on more distilled 

 water. Evaporate the clear water by heating slowly 

 and note the crust or film that is left. Continue pour- 

 ing water on the soil slowly, as before, draining away the 

 water every few hours. After several days, evaporate 

 another spoonful ; there will be less crugt or film than 

 at first. But you may go on this way for a month, 

 or a year, and still there will always be something left 

 in the spoon when you evaporate the water passing 

 through the soil, thus showing its " continuous solu- 

 bility/ 7 



Much of this dissolving action of water is due to the gases 

 it always contains, notably carbonic gas (the gas of soda 

 water); and to oxygen, the most abundant gas in the air 

 next to nitrogen, and the most important to animal life. 

 Carbonic acid (formed when carbonic gas touches water) and 

 oxygen, for instance, cause iron to rust under water, and the 



