﻿Manometer 
  for 
  High-Pressure 
  Erosions. 
  465 
  

  

  steel 
  ledge 
  *. 
  The 
  end 
  of 
  the 
  gauge 
  from 
  D 
  to 
  E 
  is 
  a 
  good 
  fit 
  

   in 
  the 
  walls 
  of 
  the 
  explosion-chamber, 
  and 
  the 
  joint 
  is 
  thus 
  

   protected 
  from 
  the 
  direct 
  effect 
  of 
  the 
  explosion. 
  

  

  Fig. 
  2.— 
  Sectional 
  Plan 
  of 
  the 
  Recording 
  Manometer. 
  

  

  The 
  spring 
  S, 
  about 
  5 
  inches 
  in 
  length, 
  is 
  tubular 
  in 
  shape. 
  

   To 
  prevent 
  any 
  buckling 
  it 
  is 
  made 
  to 
  closely 
  tit 
  the 
  cylinder 
  

   in 
  which 
  it 
  is 
  contained 
  at 
  two 
  places, 
  e 
  x 
  and 
  e 
  2 
  . 
  The 
  spring 
  

   is 
  fixed 
  at 
  the 
  outer 
  end 
  Z, 
  being 
  held 
  in 
  place 
  by 
  the 
  nut 
  K; 
  

   at 
  the 
  inner 
  end 
  it 
  is 
  free 
  and 
  supports 
  the 
  piston 
  P. 
  The 
  

   ordinary 
  U-leather 
  is 
  replaced 
  by 
  a 
  leather 
  washer 
  attached 
  

   to 
  the 
  piston 
  by 
  the 
  screw 
  C 
  and 
  to 
  the 
  fixed 
  part 
  of 
  the 
  

   gauge 
  by 
  the 
  rim 
  E. 
  The 
  end 
  of 
  the 
  piston 
  projects 
  about 
  an 
  

   hundredth 
  of 
  an 
  inch 
  above 
  the 
  rim 
  H, 
  and 
  it 
  can 
  therefore 
  

   move 
  back 
  without 
  straining 
  the 
  leather. 
  

  

  The 
  mirror 
  (not 
  visible 
  in 
  the 
  figure) 
  is 
  carried 
  by 
  the 
  

   lever 
  L. 
  This 
  lever 
  is 
  so 
  designed 
  that 
  the 
  knife-edges 
  1, 
  2, 
  

   and 
  3 
  (see 
  fig. 
  1) 
  are 
  in 
  the 
  same 
  plane, 
  it 
  being 
  at 
  the 
  same 
  

   time 
  possible 
  to 
  bring 
  the 
  knife-edges 
  2 
  and 
  3 
  within 
  one- 
  

   hundredth 
  of 
  an 
  inch 
  of 
  each 
  other 
  should 
  so 
  great 
  amplifi- 
  

   cation 
  be 
  found 
  necessary. 
  Up 
  to 
  the 
  present, 
  however, 
  the 
  

   distance 
  has 
  not 
  been 
  decreased 
  below 
  ^ 
  inch, 
  the 
  scale 
  

   obtained 
  with 
  this 
  distance 
  being 
  found 
  

  

  i 
  

   ?atisfactor 
  

  

  inch, 
  the 
  

  

  * 
  In 
  the 
  case 
  of 
  apparatus 
  designed 
  for 
  gases 
  under 
  high 
  pressures 
  all 
  

   joints 
  should 
  be 
  made 
  directly 
  metal 
  to 
  metal, 
  no 
  packing 
  being 
  used. 
  A 
  

   joint 
  thus 
  made, 
  if 
  properly 
  designed, 
  is 
  and 
  remains 
  absolutely 
  air-tight. 
  

   It 
  can 
  be 
  made 
  or 
  broken 
  in 
  an 
  instant, 
  and 
  as 
  many 
  times 
  as 
  may 
  be 
  

   required. 
  

  

  