The soil and the plant 



69 



quantities of water on the plant growth. Both methods 

 must be used, but it may be more convenient to start 

 the experiments first, and while they are going on to 

 collect observations in your rambles. 



Fill four glazed pots with dry soil: keep one dry; 

 one only just moist; the third is to be very moist and 

 should be watered more frequently than the second; 

 and the fourth is to be kept flooded with water, any way 



Fig. 32. 



Mustard growing in soils supplied with varying quantities of water. 



16 very little water, 3 a nice amount of water, 15 too 



much water 



out being stopped up. Sow wheat or mustard in all four 

 and keep out of the rain. The result of one experiment 

 with mustard is shown in Fig. 32. Where no water was 

 supplied there was no growth and the seeds remained 

 unaltered. Where only little water was supplied (Pot 

 16) the plants made some growth, but not very much: 

 the leaves were small and showed no great vigour; 



