14 SEEDS 
exp. I come up, cover some of them with an opaque jar 
so as to exclude all light. Study these plants from day to 
day for a week or more. Results; conclusions? 
Exp. 16, Class: This experiment is intended to show 
which chemical elements are necessary in the soil in 
order to insure normal development in green plants. 
Plant a small handful of corn in a flower pot con- 
taining sawdust and keep it in a warm place where ger- 
mination will take place rapidly. Procure nine jars holding 
one liter each and flat corks large enough to fit them. 
Put four holes about 2 mm. 1n diameter thru each cork 
and pass a glass tube about 10 cm. long thru one. Wash 
the jars, corks, and tubes in a weak solution of hydro- 
chloric acid, rinse them in water, then sterilize them by 
immersing in boiling water, and finally wash them in dis- 
tilled water. Fill the jars nearly full of distilled water 
and label them 1, 2, 3, etc. To the water in jar No. 1 add 
the following compounds and label it “All”: 
Potassnit, Mtrate. 00. 244 ike I gram. 
Calcium -sullate 26. 446% bes 0.5 gram. 
Nagwesum) siliate: ese. ccs eR 0.5 gram. 
Calcium phosphate (pulverized)..0.5 gram. 
Sot ahbord. . eek i ie ae 0.5 gram. 
Chlorid of iron (weak solution)...0.5.¢. c. 
Note the elements found in these compounds. 
Jar No. 2.—Add to the water in this jar the same 
coinpounds as were added to No. 1, but add sodium 
nitrate in place of potassium nitrate. Label “All minus 
potassium.” 
