PLANT PROPAGATION 109 



sponge about half the size of the fist (a wad of cotton or paper 

 will answer). Label the first tumbler No. 1, and place upon 

 the sponge 10 pea seeds that have been soaked for 24 hours. 

 In the second tumbler (labeled No. 2) put 10 soaked peas, and 

 add enough water to come nearly to the top of the sponge. 

 Put 10 soaked pea seeds into the other tumbler (No. 3), and 

 add sufficient water to cover all the peas. To prevent the 

 evaporation of the water, cover the three tumblers, and place 

 them side by side in a moderately warm temperature (65- 

 70 F.), and label each " Please do not disturb." 



1. Which one of the five conditions (enumerated in 118 above) is 



different for the three groups of seeds ? 



2. Name all of these conditions which are practically the same for 



the seeds in all three of the tumblers. 



3. At the end of a few days compare the seeds in the three tum- 



blers. What percentage of the seeds in each of the three tum- 

 blers has germinated ? 



4. State clearly your conclusion as to the relation of water to the 



germination of pea seeds. 



5. Allow the three tumblers to stand side by side in a warm, light 



place for several weeks. Describe the changes that take place 

 in each tumbler, and state your conclusion as to the relation 

 of moisture to the growth of pea plants. 



120. Relation of temperature to germination and growth. Labo- 

 ratory Study No. 57. (Optional.) Suggested as home work. 



Prepare three tumblers with sponges (cotton or paper) as in 119 

 above, putting in water enough to come nearly to the top of 

 the sponge in each dish. In each tumbler place 10 soaked 

 peas, and put on the covers. Label No. 1, No. 2, and No. 3. 

 Set tumbler No. 1 in the refrigerator or in some place where 

 it will not freeze. Keep Tumbler No. 2 at the temperature 

 of the living room. Place No. 3 where the temperature is 

 over 100. Make sure that all tumblers have about the 

 same amount of light by covering each with black paper or a 

 cloth. By the aid of a thermometer find and record the tem- 



