CAN STRONTIUM AND BARIUM REPLACE CALCIUM. 71 



A) SAND CULTURE. 



1. BUCKWHEAT. (Polygonum fagopyrum.) 



Common sea sand was boiled with strong hydrochloric acid 

 (sp. gr 1.1 5) for about two hours and then well washed at first 

 with hot water and afterwards with distilled water until no trace 

 of hydrochloric acid was present. The purified sand thus pre- 

 pared was then transfered into four large funnels, of the diameter 

 of about 25 cm., each of which was placed upon a tall glass 

 cylinder, so that the excess of the solution added to the sand 

 may pass through the funnel and drop down into the cylinder, 

 without leaving any excess in it and yet keeping all equally 

 moist. 



Seeds of buckwheat were previously soaked with water and 

 on March 26, they were equally distributed into the four funnels 



and kept in a warm house. By April 5, the germinating plants 

 reached 3-8 cm. high. They were then treated with the follow- 

 ing solutions prepared exactly after Haselhoff. 



( 2.02 g. KNO3 with 0.94 g. K 2 0+ 1.08 g. N 2 C _ 



1 ) J }■ in 1 litre water. 



2) 



3) 



4) 



5) 



j 2.02 g. KNO3 with 



0.94 g. 



K 2 0+i.o8g. N 2 O s j 



( 3 .28g.Ca(N0 3 ) 2 



1.15 g- 



CaO + 2.16 g.N 2 O s ( 



j 2.02 g. KNO3 



0.94 g. 



K 2 0 + i.o8g.N 2 CU 



(4.23 g. Sr(N0 3 ) 2 



2.07 g. 



SrO +2.16 g. N 2 O s f 



j 2.02 g. KNO3 



0.94 g. 



K 2 0+i.o8g. N 2 0„| 



( 5 .22g.Ba(NO s ) 2 



3-o6 g. 



BaO + 2.16 g. N 2 O b ) 



2.02 g. KNO3 „ 



0.94 g- 



K 2 0+i.o8 g. N 2 0 



j 1.64 g. Ca(NO s ) 2 



0-57S g- 



CaO+1.08 g. N 2 0 5 ( 



' 2.12 g. Sr(NO a ) 2 



1.04 g. 



SrO +1.08 g. N 2 0 5 ' 



5-26g.MgS0 4 + 7lI 2 0 „ 



0.86 g. 



MgO+i.7og. S0 3 



j 3.36 g. K 2 HP0 4 



1.82 g. 



K 2 0+i.o8g. P 2 0 5 ( 



' Traces of FeCI, 







From April 5, each funnel was treated with the solutions 

 1), 2), 3) and 4), respectively, and once in every 4-5 days, the 

 solution 5) was added to each funnel, so that the plants in all 

 the funnels may enjoy an equal amount of mineral salts except 



