Kentuclry Agricultural Experiment Sll(Il(’Z`0}l· 21
using new acid-proof stoneware jars for the controls. Under
these conditions the results have been more consistent than
heretofore, previous experience having shown that the ordi-
tny. nary earthenware jars may supply mineral nutrients. The
new results are consistent in showing that the plants tried do
not mature in sand cultures containing the common plant
nutrients but no manganese, whereas the same kinds of plants,
under exactly similar conditions, except for the addition of a
e. little manganese compound, grow normally. The work this
ora- year confirms the conclusion heretofore drawn from previous
experiments, that manganese is one of the elements necessary
ects to the normal growth of green plants and that it functions in
cate minute quantity. The possibility exists, however, that some
lur- other metal or combination of metals may function in the same
way, and this alternative is being investigated. Some of the
sand cultures with wheat, oats and tomatoes suggest that cop-
5up- per and zinc may perform an essential function in the frueti-
fication and development ofthe seeds of plants. A supply of
{MS quartz sand is being purified for use in experimentation along
wie this line with copper, zinc, nickel and cobalt. using sand cul-
,,,0,1 tures of some of the important agricultural plants.
ater Examination of Soils and Plants for Uncommon Elements. _
low { Using the hydrochloric acid solution from l kilogram of soil,
znall