68 



SOILS AND PLANT LIFE 



and makes its best growth. We can not control the tem- 

 perature during our experiments as we did the other two 

 factors, oxygen and moisture. The figures which were 

 given in Section 18 were secured by using germinating 

 boxes, in which the temperature was controlled as we 

 control it in an incubator. 



We all know in a general way about what time of year 

 it is best to plant the different seeds. Secure the help of 

 any experienced person in your neighborhood and arrange 

 in your notebook a table similar to the following, using 

 as many different kinds of seed as you like : 



Kind op Seed 



Date of Earliest 

 Planting with 

 Estimate op 

 AvEBAQE Tempera- 

 ture 



Date op Latest 

 Planting with 

 Estimate op 

 Average Tempera- 

 ture 



Date of Plant- 

 ing FOR Best 

 Results with 

 Estimate op 



Average 

 Temperature 



Sweet peas . 

 Com . . . 

 Muskmelon . 



Mar. 10 40 F. 

 Apr. 15 55 F 

 May 10 65 F 



May 1 63 F 

 June 1 75 F 

 June 20 80 F. 



April 1 50 F. 

 May 10 65 F. 

 June 1 75 F. 



Review Chapter IV, and state clearly all the plans, or 

 methods, you know, by which a farmer might cause the 

 temperature of his fields to be higher in the spring than 

 that of adjoining farms. 



49. Changes which take place within the Germinat- 

 ing Seed. — We have already learned that " a seed is a 

 living organism." (Section 43.) This being the case, 

 we should expect it to take in oxygen, burn up, or oxidize, 

 the stored food within it, and throw off carbon dioxide. 

 We know that we take oxygen into our lungs ; that this 

 oxygen is used to bum up, or oxidize, the food after it has 

 reached the blood ; and that carbon dioxide is thrown off. 



