The  Woburn  Pot-Culture  Experiments,  1908.  389 
“Square  Head’s  Master”  wheat,  previously  dressed  with  hot 
water,  was  sown  on  Noveinber  28,  1907.  The  seed  germinated 
well,  in  no  case  less  than  83  per  cent,  of  the  seed  coming  up. 
The  first  change  to  be  noticed  was  that,  by  the  middle  of 
March,  1908,  the  plants  to  which  lithium  chloride  had  been 
given  assumed  a very  sichly  look,  the  foliage  turning  very 
yellow.  With  lithium  sulphate  the  effect  was  of  the  same 
kind,  though  not  so  marked,  while  the  plants  treated  with 
lithium  carbonate  suffered  most.  Those  grown  with  lithium 
nitrate  had  a darker  colour  than  the  rest,  but  did  not  look  well. 
With  potash  salts,  on  the  contrary,  all  the  sets  throve,  and  the 
nitrate  one,  though  not  at  first  looking  so  well,  improved 
greatly  later  on  and  seemed  to  be  the  best  of  the  series. 
The  wheat  came  into  ear  on  June  23  in  the  case  of  the 
potash  salts,  and  a few  days  later  where  the  lithium  salts  were 
used.  When  the  produce  was  weighed,  the  following  results 
were  obtained  : — 
Corn 
Straw 
Weight 
Percentage 
of  untreated 
Weight 
Percentage 
of  untreated 
No  treatment 
Grammes 
29-40 
Per  cent. 
100-00 
Grammes 
47-92 
Per  cent. 
100-00 
Lithium  chloride. 
19-37 
65-90 
25-16 
52-50 
Lithium  sulphate 
17-65 
60-00 
23-79 
49-60 
Lithium  carbonate 
14-73 
50-30 
19-66 
41-00 
Lithium  nitrate  . 
21-82 
74-50 
31-16 
65-10 
No  treatment 
29-40 
100-00 
47-92 
100-00 
Potassium  chloride 
29-80 
101-40 
46-95 
97-90 
Potassium  sulphate 
29-10 
99-01 
50-08 
104-50 
Potassium  carbonate  . 
26-56 
90-30 
43-00 
89-70 
Potassium  nitrate 
31-37 
106-70 
48-14 
100-40 
From  these  figures  it  will  be  seen  that  in  every  case  where 
lithium  salts  were  used  there  was  an  injurious  influence,  this 
being  most  marked  with  the  carbonate  and  least  with  the 
nitrate.  With  potash  salts  a tendency  in  this  same  direction 
was  shown  with  the  carbonate,  but  with  none  of  the  other 
salts.  It  is  evident,  therefore,  that  when  even  as  little  as 
•00375  parts  of  lithium  are  present  in  100  parts  of  soil,  a harm- 
ful influence  will  be  exerted  on  a wheat  crop.  The  experiments 
will  be  continued  with  even  smaller  quantities  of  lithium. 
2.  Green-manuring  Experiment. 
This  experiment  was  devised  with  the  object  of  explaining 
the  seemingly  anomalous  results  obtained  in  the  green-manuring 
experiments  in  Lansome  Field  (see  page  375),  where,  for  a 
number  of  years  a better  corn  crop  has  followed  the  ploughing- in 
