Cambridge  University  Agricultural  Department.  215 
the  manner  of  sowing,  a fairly  even  plant  of  white  clover  was 
secured,  hut  the  crop  was  very  2)Oor  and  made  hardly  any 
growth  in  the  summer"  of  1004.  When  clover  was  sown  on 
a part  of  the  soil  which  had  received  basic  slag,  however,  it 
developed  in  the  most  luxuriant  fashion,  just  as  it  does  on  soils 
naturally  suited  to  the  action  of  slag.  The  turfs  com])rising  the 
exhibit  showed — (1)  untreated  soil ; (2)  land  on  which  clover 
had  been  sown  ; (3)  land  to  which  manures  had  been  applied  ; 
and  (4)  manured  land  on  which  clover  had  been  sown.  There 
was  no  striking  result  except  in  the  case  of  the  turf  representing 
land  which  had  received  both  seed  and  the  manure.  This  gave 
very  clear  evidence  that  two  things  are  necessary  for  the 
im])rovement  of  j)oor  clay  pastures — (1)  a phosjdiatic  manure, 
(2)  a clover  plant. 
The  chemical  composition  of  root  crops  was  explained 
by  a number  of  diagrams  showing  the  percentage  of  dry 
matter  and  sugar  in  mangels,  swedes,  and  common  turnips 
grown  in  1903,  and  the  variation  of  these  constituents  due  to 
individuality,  variety,  soil,  and  season.  In  the  case  of  the  mangel 
the  percentage  of  nitrogen  (proteid  and  amide)  in  100  indi- 
vidual roots  of  the  same  variety  was  shown,  in  addition  to  their 
dry  matter  and  sugar  contents.  The  object  of  the  experiments 
was  to  select  roots  for  reproduction  having  the  highest  per- 
centage of  dry  matter,  and  the  results  show  how  great  is  the 
variation  in  individual  roots  of  the  same  kind  grown  under 
similar  conditions,  and  also  that  soil  and  climate  have  a great 
effect  in  varying  the  composition  of  roots  of  the  same  kind. 
A set  of  mangel  diagrams  showed — (1)  Percentages  of 
dry  matter  and  sugar  in  nine  varieties  grown  on  different  soils 
at  three  stations  in  Norfolk,  and  one  each  in  Cambridgeshire 
and  Bedford.  Taking  the  average  percentage  of  dry  matter 
and  sugar  in  the  nine  varieties,  the  highest  was  13'2  per 
cent,  dry  matter,  and  9‘3  per  cent,  sugar,  grown  on  a medium 
soil  in  Cambridge,  while  the  lowest  was  10"2  per  cent,  dry 
matter,  and  6‘4  per  cent,  sugar,  grown  on  a light  loam  in 
Norfolk.  At  no  two  stations  was  any  one  variety  the  best,  but 
the  yellow  globe  invariably  came  out  the  lowest  in  dry  matter 
and  sugar  at  the  five  stations.  (2)  Variation  in  dry  matter, 
sugar,  nitrogen  (j)roteid  and  amide),  in  100  individual  roots  of 
Sutton’s  Golden  Globe.  It  was  shown  that  there  was  an 
enormous  variation  in  the  amount  of  dry  matter  and  sugar 
present  in  different  mangels  of  the  same  variety.  The  highest 
percentage  of  dry  matter  found  was  15"5,  and  the  lowest  8’7  ; 
