60 GERMINATION OF SEEDS 



the other on a side, thus forming an inclined plane. Now 

 add water to the tray slowly so that it may be absorbed by 

 the blotting paper without the lower seeds floating off. 

 Gradually the water will pass up the paper by capillary 

 force and after a time the whole will become moist. But 

 the amount of water will vary with the distance from the 

 level in the pan, and thus the seeds upon the blotter will 

 receive varying amounts of water, depending upon their 

 nearness or remoteness from the water in the pan. Leave 

 the apparatus in a warm room for several days and note the 

 result. Do all the seeds sprout alike? Do the same seeds 

 sprout equally well at all distances from the water ? 



Conclusion. State what you infer as to the need of 

 water by growing seeds and whether all seeds are alike in 

 their water requirements. 



Note. The water in the tray should be kept at the same level 

 and the atmospheric conditions should be kept uniform if possible. 



44. THE HEAT FACTOR 



Object. To find how to make the embryo plant begin 

 to grow. 



Apparatus. Three bottles arranged as in Experiment 42, or 

 three plates with blotting paper and cover glasses. 



Method. Prepare the seeds in damp sawdust (B, Experi- 

 ment 42), or plant them on wet blotting paper on plates 

 and cover them with plates of glass. 



Now place the bottles or plates in three different localities 

 where they will be alike in all respects save amount of 

 heat. 



Put A where it is very cold, as in a refrigerator if in summer, 

 or on the outside of a window sill if in winter. Place B 



