Groivth o/Lernna minor in Mineral Culture Solutions. 491 



Table V. 



Series. 



At beginning of 

 experiment. 



3rd week. 



4th week. 



5th week. 



6th week. 





mgrm. 



mgrm. 



mgrm. 



mgrm. 



mgrm. 



I 



12 -0 



13 -0 



8-8 



5 9 



5-4 



II 



12 -0 



16 -4 



16o 



16 -7 



16-4 



in 



12-0 



14-3 



14 -7 



15 -3 



16 -5 



IV 



12 -0 



13 -6 



10 -8 



11 -3 



11 -8 



V 



12 -0 



13 1 



11 -5 



9-6 



9-0 



These figures are graphically represented in the diagram below. 



O I Z . 3 4 5 6 

 Time in weeks 



Fig. 3. 



1. Series I : Detmer's solution. 



2. „ II: „ „ + complete water extract. 



3. „ III : „ „ + water extract free from humic acid. 



4. „ IV: „ n + alcoholic extract. 



5. „ V: ,, „ + phosphotungstie fraction. 



A measure of the comparative rapidity with which the plants in each series 

 doubled their number and their weight is obtained by putting the number of 

 times which the plants of Series I doubled themselves in a given time at 



