604 
Report  on  Implements  at  York. 
action  of  the  air,  when  it  reaches  this  point  falls  back  again,  owing  to  the 
reduced,  pressure  due  to  the  enlarged  area.  This  is  a very  ingenious  and 
important  detail.  In  the  machine  exhibited  at  York  a portion  of  the 
wooden  coveriDg  was  replaced  by  glass,  allowing  the  spectator  to  witness  the 
balancing  action  of  the  wind,  which,  as  will  be  seen,  is  under  delicate  con- 
trol, so  that  we  have  the  perfect  action  of  a blower  removing  light  corn 
before  the  size  of  the  grains  are  made  the  means  of  separation  by  the  revolving 
cylinder  r.  Pursuing  our  enquiry,  we  find  the  air  plus  the  chaff  scales,  &c., 
drawn  from  the  pocket  d through  the  tubes  d and  e into  the  exhaust  fan  f. 
The  first  winnowing  operation  is  performed  in  the  dressing-chest  by  means  of 
the  fan,  which  draws  the  chaff  through  a pipe  or  extra  chamber,  and  blows  it 
up  a tube  to  the  spouts  g g,  when  it  falls  into  chaff-bags,  or  is  otherwise 
removed.  But  as  it  passes  through  the  fan  it  is  cleaned  from  dust  by  means 
of  the  perforated  casing  m m (Fig.  4),  and  the  sliding  valve  h (Fig.  5)  in  the 
air-chamber  of  the  riddle-box,  and  the  air  inlet  at  u (Fig.  4). 
Fig.  5. — End  view  partially  in  section. 
Reference  has  been  made  to  the  nature  of  the  scourer.  The  following 
figures,  which  accompanied  the  first  specification  of  Oct.  21,  1881,  will  more 
fully  explain  the  details  of  this  important  portion  of  the  machine. 
In  Fig.  6,  J is  the  ribbed  lining  which  is  secured  by  bolts  l to  the  outer 
covering  k ; by  removing  the  bolts  the  lining  can  be  taken  out  and  reversed, 
and  thus  its  efficiency  and  durability  is  doubled.  Fig.  7 shows  the  valve  b, 
which  opens  outwards,  and  is  useful  in  the  case  of  wet  or  smutty  grain, 
which  should  not  go  into  the  scourer  c.  m is  a valve  which  can  be  set  more 
or  less  open,  and  by  which  the  passage  of  the  corn  from  the  scourer  is  regu- 
