350 



APPENDIX E. 



I. Experiments of Knop. 



Knop based his experiments with maize on the earlier observa- 

 tions which he had made on the vegetation of barley and cresses 

 (see'Chem. Central Blatt,' 1861, s. 564). According to these 

 observations the gramnreae require for their growth nothing more 

 than a normal solution, which contains sulphate of magnesia, 

 nitrate of lime, and nitrate of potash, according to the proportion 

 MgOS0 3 +"2CaON0 5 + 2KON0 3 , in which phosphate of iron was 

 suspended, and phosphate of potash as required was dissolved. 

 The normal solution A made according to the above formula con- 

 tained in grammes 



100 cent. cub. 

 Nitric acid . . 



0-2160 



Sulphuric acid 0*0495 



Lime 0*0684 



Magnesia 0*0233 



Potash 0-0940 



0-4512 



500 cent. cub. 

 1-0800 

 0-2475 

 0-3420 

 0-1165 

 0-4700 



2-2560 



600 cent. cub. 

 1-2960 

 0-2970 

 0-4104 

 0-1398 

 0-5640 



2-7072 



In consequence of using the solution in a more dilute form in 

 the first period, in order to promote a better radication, 600 cubic 

 centimetres of the above solution were employed at this time ; at 

 every other period, 500 cubic centimetres were measured off, and 

 to this last quantity the phosphate of potash was now added in 

 the proportion indicated. The mixture, therefore, had the fol- 

 lowing composition in the five periods. The potash which was 

 added as KOPOa, and as KONOs, are given separately and united 

 with a bracket. 



Period. 



I. 12 cent. cub. solution of KOP0 5( * 600 cent. cub. normal solution A. 



II. 10 " " 500 " " 

 III. & IV. 20 " " 500 " 



V. 30 " " 500 " " 



In these solutions are contained in grammes, 



* 10 cent. cub. of the solution contained exactly 1 decigramme of KOPO S 



