Report  on  Implements  at  York. 
609' 
periphery,  into  which,  when  the  shaft  is  turned  so  as  to  bring 
the  ploughshares  into  their  lowest  position,  a pawl  on  the  frame 
catches  so  as  to  hold  the  shaft  in  that  position.  By  this  arrange- 
ment it  will  be  evident  that  the  uplifted  ploughs  do  not  act  as  a 
counterpoise  to  those  in  the  ground  ; and  hence,  however  rapidly 
the  implement  travels,  there  is  no  tendency  to  jerkiness,  or  jump- 
ing out  of  work.  The  mode  of  turning  the  implement  and 
raising  the  frame  by  means  of  the  cranked  axle  are  too  well  known 
in  connection  with  the  turning  cultivator  to  require  description. 
The  pawl  referred  to,  as  holding  the  operative  ploughs  to  their 
work,  is  released  as  the  implement  is  being  turned  ; and  the 
attendant  pulls  down  the  uplifted  ploughs,  which  he  does  quite 
easily.  Formerly,  as  is  shown  in  the  drawing,  this  was  done 
mechanically  by  connecting  the  end  of  the  lever  H by  chains,  a5, 
working  round  friction  pulleys  attached  to  each  end  of  the 
rotating  shaft  to  the  pulleys,  a 3.  This  answered  quite  well ; 
Fig.  10. — Plan  of  front  part  of  Plough. 
JL 
<53 
but  as  an  attendant  is  required  for  travelling,  it  was  considered 
desirable  to  utilize  his  services,  and  thus  slightly  reduce  the 
cost  and  complication  of  the  machine.  Originally,  the  plough 
frames  or  skaifs  were  of  cast  iron,  and  their  great  weight  was 
objectionable.  Now  steel  is  used,  and  the  lowering  of  the 
ploughs  is  a very  simple  business.  It  may  be  as  well  to  very 
briefly  describe  the  different  parts  by  reference  to  the  letters 
on  the  drawings. 
a a b b show  the  back  and  front  portions  of  the  frame,  carried  on  a pair  of 
travelling  wheels  c c,  with  broad  tires  ; these  wheels  are  placed  under  the 
centre  of  the  frame,  and  are  covered  by  the  ploughs,  so  that  any  injury  to  the 
surface  from  the  weight  of  the  implement  is  minimized  by  the  fact  that  the 
wheel-tracks  are  at  once  destroyed.  Moreover,  the  wheels  travel  on  the  hard 
ground,  and  the  increased  surface  of  the  tires  causes  a distribution  of  the 
