50 MANUAL OF GENERAL AGRICULTURE. 



one with beans, one with corn, as follows: Plant two 

 seeds near together against the wall of the jar and on the 

 surface of the soil. Add an inch of soil, press it down 

 firmly and after turning the jar slightly to one side, 

 plant two more seeds so that they will not be directly over 

 those already planted. Continue to add soil and plant 

 seeds every inch up the side of the jar till near the top. 

 Wrap each jar in dark cloth or paper to exclude the light, 

 and set in a warm place. From day to day, remove the 

 wrapping from the jars and note the growth, recovering 

 them immediately. This exercise should give some idea 

 of the power of different kinds of seeds to force their 

 plantlets up through the soil. Note the depth of the low- 

 est seed in the jars that is able to penetrate to the surface. 



(b) Small Seeds. Eepeat (a) using the pint jars 

 and planting the lowest seeds about an inch from the bot- 

 toms. Use small seeds, such as radish, alfalfa, clover. 



How do the depths of germination with large seeds 

 and small compare? Give reason for this. Oil producing 

 seeds contain much more food in proportion to their size 

 than do the starchy seeds. 



51. OSMOSIS. 



Materials: Potato, two wide mouth glasses or beak- 

 ers, glass tube 6 inches long and about 3-16 inch inside 

 diameter, egg, hatpin, sealing wax, salt. 



1. Pare a potato and cut slices from it. Place some 

 of these in water and some in a strong solution of salt 

 made by placing a small handful of salt into a glass of 

 water. Examine at the next exercise. 



2. Cement with sealing wax to the smaller end of an 

 egg a piece of glass tubing about 6 inches long and about 

 3-16 inch inside diameter. Clip away part of the shell 

 from the larger end of the egg, place in a wide mouth bot- 

 tle or small beaker full of water and then carefully pierce 

 a hole through the upper end of the eggshell by pushing 

 a hatpin through the glass tube. Examine at the next 

 exercise. 



