THE PLANT 



57 



What does 



is often called ' the blue grass country.' Nearly all plants flourish 

 on a mellow loam, because it is well supplied with moisture, 

 warmth, and air. 



EXPERIMENTS 



1. Weigh a plant, such as cotton. Put it in the stove and let it dry 

 thoroughly. Then weigh again. What has the plant lost? Take off 

 the leaves and weigh them. Burn them and weigh the ashes. Weigh 

 the stem, and then burn it and weigh the ashes. The ashes are the soil- 

 derived elements. What difference is there between the quantity in 

 leaves and in stem? 



2. Burn an equal weight of dry straw and dry tobacco, 

 this experiment show as to the 



composition of plants ? 



3. Put some grains of corn 

 in a bottle of pure distilled 

 water. What happens as soon 

 as the plants use up the store 

 of food in the seeds ? 



4. Put in another bottle water 

 supplied with plant food in the 

 following proportions : 



Distilled water 1000.0 grams 

 Potassium nitrate i.o grams 

 Calcium phosphate .5 grams 

 Calcium sulphate .5 grams 

 Magnesium sulphate .5 grams 

 A trace of iron sulphate 



Put some grains of corn in this 

 water. Renew the solution fre- 

 quently and keep the bottle covered with dark paper. Prepare other 

 bottles of distilled water, omitting one or more of these food elements. 

 What are the results ? Use all the elements with one fourth this quantity 

 of water. What does this prove about the oversupply of plant food? 



5. Collect legumes and examine tubercles on the roots. 



The plant on the right is supplied with plant 

 food in the proper amount of water ; the plant 

 on the left has similar plant food in one fourth 

 the amount of water. fc 



