66 



GERMINATION OF SEEDS 



.germinating 

 seeds 



...Limewater 



FIG. 19. 



Method. In a wide-mouth bottle place a small vessel 

 of lime water and fill around it with germinating seeds. 



Cork the bottle tightly to pre- 

 vent entrance of air. 



After three days remove 

 the cork. Test the gas above 

 the seeds with a burning stick. 

 Result? 



Examine the dish of lime- 

 water. What change has taken 

 place in it? Proof? 



Conclusion. What is given 

 off by germinating seeds ? 

 Note. See also Experiment 46. 



Note. A device to show that germinating seeds use up the 

 oxygen of the air and set free carbon dioxide may be arranged as 

 follows : 



Germinate some oats, wheat, or other similar seeds by planting 

 soaked seeds between folds of wet flannel or blotting paper. When 

 the roots and shoots are well started, fill the large end of a thistle 

 tube with them and close it with a cork. 



Now clamp it in a vertical position so that the small end will 

 rest in a beaker of strong potash water or limewater. 



When the young plants have consumed the oxygen in the sur- 

 rounding air of the thistle tube, and given off the corresponding 

 amount of carbon dioxide, the liquid in the beaker will rise in the 

 tube. This is because caustic potash and limewater have a strong 

 affinity for carbon dioxide. If the liquid is colored with eosin, its 

 rise in the tube will be more apparent. 



50. HEAT FROM GERMINATION 



Object. To find out whether germinating seeds give 

 off heat. 



Apparatus. Two thermometers, two flowerpots, and seeds. 



