EXPERIMENTS 15 
Jar Nc. 3—Same as No. 1, excepting potassium phos- 
phate in place of calcium phosphate and omit calcium 
sulfate. Label “All minus calcium.” 
Jar No. 4—Same as No. 1, excepting magnesium 
chlorid in place of magnesium sulfate, and omit calcium 
sulfate. Label “All minus sulfur.” 
Jar No. 5—Same as No. I, excepting omit calcium 
phosphate. Label “All minus phosphorus.” 
Jar No. 6—Same as No. 1, excepting omit magne- 
sium sulfate. Label “All minus magnesium.” 
Jar No. 7—Same as No. 6, excepting potassium 
chlorid in place of potassium nitrate. Label “Ali minus 
nitrogen.” 
Jar No. 8—Same as No. 1, excepting omit iron 
chiorid. Label “All minus iron.” 
Jar No. g—Omit all chemicals. Label “distilled 
water.” 
After the corn seedlings planted in sawdust have 
plumules about 2 cm. long, select 27 vigorous speci- 
mens, put them into water as soon as taken from the 
sawdust, handle them very carefully, remove all particles 
of substance clinging to the roots, with a camels hair 
brush, wash them thoroly, and rinse them in distilled 
water. Push the plumule of a seedling thru each hole in 
the corks from below, and fasten it by filling the space 
around it with cotton. Fill all crevices around the corks 
with cotton and plug the upper end of the glass tubes. 
Wrap opaque paper around the jars, fasten it so as to 
exclude all light, and put the labels on the outside. Set 
these jars where they will be in direct sunlight at least 
part of the dav. Replace the water evaporated by adding 
