ash bank, however well it might be watered. If there is a potted 

 plant at hand which is of no value, we might remove some of the 

 soil, add considerable wood ashes, water well, and await the 

 result. Try it ; or give it a lump of nitrate of soda. 



II. The soil water is a very dilute solution. — In Reading- Les- 

 son No. 2 the different kinds of water in the soil were men- 

 tioned ; and it was stated that the water which is valuable to the 

 plant is not the free water, but the thin film of moisture which 

 , adheres to each little particle of soil. Any one 



X^V/' <_«!i^<^ who has drunk w^ater from a tile drain knows 



that at least the free water w^hich has soaked 

 from the soil must contain relatively very little 

 plant-food, else our delicate taste would detect 

 it. Perhaps the film moisture contains a little 

 more plant-food than the free water, but the 

 quantity of substances in solution is generally 

 extreme!}' minute, so that the soil water is 

 readih' absorbed by the plant. 



12. Root absorptio7i may continue in a soil 

 that seems to be dry. — Not only is free water 

 unnecessar}' for ordinary land plants, but the 

 amount of film moisture present does not 

 need to be very great. It is remarkable how^ 

 dr}' a soil may feel to the fingers, and yet 

 afford sufficient water to maintain the plant. 

 This may be readih' studied with a potted 

 plant, or observed in the field. 



13. The roots need air. — Corn on a piece of 

 land w^hich has been flooded b}^ the heavy rains looses its green 

 color and turns yellow. Besides diluting plant-food, the water 

 drives the air out of the soil, and this suffocation of the roots is 

 ver}' soon felt in the general health of the plant. The film 

 moisture alone (hj'groscopic water) is best to insure proper aera- 

 tion. The value of tillage for aeration purposes has already been 

 mentioned in Reading-Lesson No. 2. Water-plants and bog- 

 plants have adapted themseleves to their particular conditions. 

 They either get their air by special surface roots, or get it 

 from the water. 



Thriving in a weak 

 solution. 



