344  The  Woburn  Pot-Culture  Experiments,  1909. 
3.  The  influence  of  Lime  on  a soil  rich  in  Magnesia. 
4.  The  influence  of  Magnesia  on  Clover  and  Beans. 
5.  Green-manuring  Experiments. 
6.  Experiments  with  Nitrogenous  Top-dressings. 
7.  Experiments  on  the  Inoculation  of  Crops. 
1.  Hills'  Experiments  — (a)  The  influence  of  salts  of 
Lithium  and  Caesium  on  Wheat. 
The  experiments  of  1908  had  shown  that  the  presence  of 
as  little  as  '00375  parts  of  lithium,  when  added,  in  the  form 
of  different  salts,  to  100  parts  of  the  Woburn  soil  exerted  a 
harmful  influence,  this  being  most  marked  with  the  carbonate 
and  least  with  the  nitrate.  In  1909  the  same  salts  were  used,  but 
in  even  lesser  amount,  viz.,  to  supply  '0018  per  cent,  of  metallic 
lithium  to  the  soil.  Along  with  this  was  a similar  experiment 
with  the  same  salts  (chloride,  sulphate,  carbonate,  and  nitrate) 
of  caesium,  the  amount  of  metallic  caesium  being,  however, 
•0036  per  cent.  As  before,  the  salts  were  closely  incorporated 
with  the  whole  of  the  soil.  The  wheat  was  first  sown  on 
November  28,  1908,  but,  owing  to  frost  and  snow,  had  to  be 
resown  on  January  18,  1909.  The  germination  was  very  fail- 
all  round  and  presented  no  special  features.  The  first 
differences  were  apparent  at  the  end  of  April,  when  the 
carbonate  of  lithium  and  the  chloride  of  lithium  plants 
looked  yellowish  and  inferior  to  the  others ; the  caesium 
plants,  however,  were  all  quite  normal.  At  the  beginning 
of  June  a great  improvement  was  shown  with  all  the  lithium 
sets,  and  it  appeared  as  if  the  point  had  been  reached  where 
the  toxic  effect  of  the  salts  was  no  longer  exerted.  Measure- 
ments of  the  straw  and  ear  showed  that  in  all  cases  of  treatment 
these  were  somewhat  less  than  with  the  untreated  lots.  The 
crops  were  cut  on  August  25,  1909,  and  the  results  obtained 
were  : — 
Corn 
Straw 
Weight 
Percentage 
of  untreated 
Weight 
Percentage 
of  untreated 
No  treatment 
Grammes 
1733 
Per  cent. 
100 
Grammes 
30-62 
Per  cent. 
100 
Lithium  chloride. 
20-79 
119 
3110 
101-6 
Lithium  sulphate 
19-98 
115 
30-96 
101-1 
Lithium  carbonate 
1990 
115 
3098 
101 
Lithium  nitrate  . 
34-27 
198 
49-96 
163 
No  treatment 
17-33 
100 
30-62 
100 
Caesium  chloride 
19-42 
112 
31-39 
102 
Caesium  sulphate 
18-74 
108 
3112 
101 
Caesium  carbonate 
15-21 
87 
27-45 
90 
Caesium  nitrate  . 
2011 
116 
34-40 
112 
