26 Mr. A. D. Hall and Dr. N. H. J. Miller. [Mar. 30, 



TABLE XIII — continued. 

 After Growth. Nos. 1 and 2. Dry Matter produced = 93-7 Grammes. 





Quantities found. 



Equivalent to hydrogen. 





Sediment. 



Solution. 



Plant. 



Sediment. 



Solution. 



Plant. 



Total. 





gramme. 



grammes. 



grammes. 



gramme. 



gramme. 



gramme. 



gramme. 





-5014 



3 -6644 





-01065 



-07796 



-08861 



MgO 



(0 -2082*) 



-2318 



0-1618 



(0 -01041) 



-01159 



-00809 



-03009 



CaO 



0-152 



1 -1592 



1 -4371 



-00543 



-04140 



-05140 



-09823 











-01584 



-06364 



-13745 



-21693 



N 



-1249 



-0103 



1 -3540 



-00892 



-00074 



-09670 



-10636 



P,0 5 



-2942 



-5631 



1 -246 



-00414 



-00793 



-01755 



-02962 



so 3 





-6448 



0-4008 





-01612 



-01002 



-02614 



CI 





-8114 



1 -3461 





-02285 



-03792 



-06077 











-01306 



-04764 



-16219 



-22289 







+ 0-00278 



+ 0-01600 



-0 -02474 



-0-00596 



After Growth. 



Nos. 3 and 4. Dry Matter produced = 



77 - 6 Grammes. 



KoO 





-6736 



3 -4819 





-01433 



-07410 



-08843 



MgO 



(0 -1296*) 



-2413 



-2309 



(0 -00648) 



-01206 



-01154 



-03008 



CaO 



-2240 



1 -2222 



1 -3414 



-00800 



-04365 



-04790 



-09955 











-01448 



-07004 



-13354 



-21806 



N 



-0972 



0-0080 



1 -4038 



-00694 



-00055 



-10027 



-10776 



P-A 



0-345 



-5765 



1 -170 



-00486 



-00812 



-01648 



-02946 



SO, 





-6610 



-3959 





-01652 



-00990 



-02642 



CI 





-8595 



1 -2212 





-02421 



-03440 



-05861 











-01180 



-04940 



-16105 



-22225 





Bases in excess 



+ 0-00268 



+ -02064 



-0-02751 



-0-00419 



* Estimated figure — these two determinations were lost. 



0-0036 gramme nitrogen, equivalent to - 00026 gramme hydrogen), and partly 

 to a trace of ammonia in the large quantities of distilled water evaporated 

 during growth. This excess of nitrogen accounts for the slight excess of acid 

 over base in the final result when all the nitrogen is reckoned as acid. It 

 will be seen that the solution and sediment (representing the soil) gained in 

 the one case base equivalent to 0-01878 gramme of hydrogen and in the other 

 to 0-02332 gramme of hydrogen, quantities which would probably have been 

 increased had the growth not been continued until all the nitrate was 

 exhausted. 



It has been often supposed that plants excrete some organic acid from the 



