﻿1875.] 
  

  

  Exact 
  Rectilinear 
  Motion 
  by 
  Linkwork. 
  

  

  ^75 
  

  

  § 
  13. 
  In 
  the 
  linkwork 
  of 
  § 
  11 
  make 
  

  

  a=c, 
  b— 
  — 
  d, 
  \=h, 
  and 
  make 
  D' 
  and 
  T 
  coincide. 
  Then 
  

  

  a 
  

  

  S, 
  L 
  coincide, 
  

   C,P 
  „ 
  

  

  v, 
  t 
  „ 
  

  

  o, 
  f 
  o 
  „ 
  

  

  B', 
  D, 
  ,, 
  

  

  and 
  the 
  bars 
  B 
  C, 
  D' 
  C 
  make 
  equal 
  angles 
  with 
  A 
  B 
  in 
  opposite 
  directions 
  ; 
  

   and 
  the 
  linkwork 
  is 
  one 
  of 
  those 
  given 
  by 
  me 
  in 
  the 
  * 
  Messenger.' 
  

  

  Fig. 
  13. 
  

  

  § 
  14. 
  The 
  peculiar 
  form 
  of 
  the 
  fundamental 
  linkwork 
  employed 
  in 
  

   the 
  last 
  case 
  may 
  easily 
  be 
  seen 
  to 
  be 
  really 
  the 
  same 
  as 
  was 
  used 
  in 
  § 
  5. 
  

   From 
  the 
  property 
  of 
  the 
  equal 
  inclination 
  of 
  the 
  bars 
  B 
  C, 
  D' 
  C 
  to 
  B 
  A, 
  

   another 
  form 
  of 
  linkwork 
  maybe 
  obtained 
  which 
  does 
  not, 
  strictly 
  speaking, 
  

   come 
  under 
  this 
  group, 
  but 
  is 
  an 
  exceptional 
  one. 
  

  

  Fig. 
  14. 
  

  

  YOL. 
  XXIIT. 
  2 
  X 
  

  

  