NUTRIENT SOLUTIONS AND WATER CULTURES. 



then made up to volume, 500 cc withdrawn for analysis, and the 

 remainder saved in which to .grow a second crop. 



Reaction of the residual solution. In Table 1 are shown the reac- 

 tions and titration data for the 13 solutions after gathering the first 

 crop ; no nitrates and only a trace of potash remained in any of the 

 solutions. 



TABLE 1. Titration of the culture solutions after the first crop was harvested. 



1 See page 6 for amounts of constituents in each solution. 



Effects of sodium nitrate. In Plate I, figure #, a slight improve- 

 ment, especially in root development, is noticed in the distilled- 

 water cultures when calcium carbonate is added, but no appreciable 

 difference is seen when the calcium carbonate is added to the sodium 

 nitrate solution. By reference to the analysis of the culture solu- 

 tions in Table 1, it will be seen that control No. 1, at the close of 

 the experiment, showed, upon boiling, a slight acid reaction. This 

 was probably due either to the exudation by the roots of some acid- 

 reacting body or to the excretion of similar bodies by the seeds them- 

 selves. Nos. 2 and 4 were, of course, alkaline because of the presence 

 of the calcium carbonate. The alkalinity of No. 3 was due to the 

 fact that all of the nitrate (NO 3 ) or acid radical in the sodium nitrate 

 had been removed by the plant, while some of the sodium or alkaline 

 radical, being less rapidly absorbed, remained in the solution, form- 

 ing, probably, sodium hydroxid. This, in turn, had taken up carbon 

 dioxid and was existing in the solution as sodium bicarbonate. 



Relative effects of potassium chlorid and hydrochloric acid. In 

 Plate I. figure &, are shown the relative effects of potassium chlorid 

 and hydrochloric acid (solutions 5 and 6, and 9 and 10). The plants 

 removed practically all of the potash from the potassium chlorid 

 solution, only a trace remaining, while by analysis 38 parts per 

 million of chlorin out of a total of 71 still remained in the solution, 



