﻿570 
  Mr. 
  A. 
  B. 
  Kenrpe 
  on 
  the 
  'production 
  of. 
  [June 
  17, 
  

  

  § 
  4. 
  If 
  in 
  this 
  last 
  linkwork 
  we 
  make 
  

  

  h—c, 
  h=~, 
  then 
  A 
  = 
  b, 
  

   a 
  

  

  and 
  

  

  P 
  coincides 
  with 
  C, 
  

   '• 
  } 
  » 
  » 
  G', 
  

   B' 
  „ 
  „ 
  D. 
  

  

  

  Fig. 
  4. 
  

  

  

  p 
  

  

  

  / 
  

  

  

  

  

  / 
  

  

  V-v 
  / 
  

  

  

  The 
  linkwork 
  then 
  assumes 
  the 
  form 
  given 
  in 
  fig. 
  4, 
  

   § 
  5. 
  Again, 
  in 
  the 
  linkwork 
  of 
  § 
  3, 
  if 
  

  

  &=4anda 
  2 
  +& 
  2 
  =c 
  2 
  + 
  d 
  2 
  , 
  

   a 
  

  

  then 
  A— 
  ^ 
  and 
  is 
  indeterminate. 
  P 
  may 
  then 
  be 
  taken 
  anywhere 
  onBC; 
  

  

  and 
  since 
  NN'=0, 
  P' 
  lies 
  vertically 
  above 
  P. 
  Also 
  PO 
  and 
  P'O 
  may 
  

   be 
  taken 
  of 
  any 
  lengths 
  so 
  long 
  as 
  

  

  P' 
  2 
  -P 
  2 
  =P' 
  B 
  2 
  -P 
  B 
  2 
  . 
  

  

  Pig. 
  5. 
  

  

  § 
  6. 
  Here 
  we 
  have 
  a 
  special 
  case 
  of 
  the 
  linkwork 
  in 
  the 
  last 
  section 
  

   in 
  which 
  a=—c,b=.d. 
  In 
  this 
  case 
  CB 
  and 
  CD' 
  are 
  equally 
  inclined 
  

  

  