﻿386 
  Dr. 
  Barton 
  and 
  Mr. 
  Laws 
  on 
  Air-Pressures 
  

  

  length 
  of 
  the 
  tubing 
  in 
  use 
  so 
  that 
  the 
  note 
  in 
  question 
  is 
  

   one 
  of 
  those 
  with 
  which 
  the 
  instrument 
  is 
  now 
  in 
  resonances 
  

   The 
  correct 
  embouchure 
  and 
  air-pressure 
  pick 
  out, 
  as 
  it 
  were, 
  

   from 
  the 
  notes 
  then 
  possible 
  to 
  the 
  instrument, 
  the 
  particular 
  

   one 
  sought, 
  and 
  cause 
  it 
  to 
  sound. 
  

  

  Some 
  of 
  the 
  problems 
  here 
  involved 
  are 
  chiefly 
  of 
  a 
  

   musical 
  character. 
  

  

  But 
  the 
  pressure 
  of 
  air 
  which 
  solicits 
  the 
  desired 
  note, 
  

   although 
  several 
  others 
  are 
  possible 
  with 
  the 
  same 
  fingering, 
  

   and 
  the 
  variations 
  of 
  this 
  pressure 
  with 
  the 
  pitch, 
  loudness, 
  

   and 
  other 
  circumstances 
  form 
  a 
  problem 
  belonging 
  rather 
  to 
  

   the 
  domain 
  of 
  physics, 
  and 
  one 
  which 
  is 
  attacked 
  in 
  the 
  

   experiments 
  here 
  described. 
  

  

  Some 
  previous 
  work 
  on 
  the 
  air-pressures 
  required 
  for 
  

   various 
  instruments 
  has 
  been 
  done 
  by 
  Dr. 
  W. 
  H. 
  Stone 
  (see 
  

   p. 
  171, 
  'Elementary 
  Lessons 
  on 
  Sound/ 
  Macmillans, 
  1891), 
  

   who 
  gives 
  maximum 
  and 
  minimum 
  pressures 
  for 
  the 
  oboe, 
  

   clarinet, 
  bassoon, 
  horn, 
  cornet, 
  trumpet, 
  euphonium, 
  and. 
  

   bombardon. 
  No 
  details, 
  however, 
  are 
  there 
  given 
  of 
  the 
  

   pressures 
  for 
  each 
  note 
  of 
  the 
  scale, 
  nor 
  of 
  the 
  variations 
  of 
  

   the 
  pressure 
  with 
  loudness. 
  

  

  The 
  present 
  work 
  deals 
  with 
  three 
  brass 
  instruments, 
  viz., 
  

   the 
  tenor 
  trombone, 
  the 
  trumpet, 
  and 
  the 
  cornet. 
  The 
  re- 
  

   sults 
  of 
  the 
  experiments 
  on 
  these 
  are 
  sufficiently 
  consistent 
  

   to 
  support 
  certain 
  general 
  conclusions 
  which 
  are 
  summarized 
  

   at 
  the 
  close 
  of 
  the 
  paper. 
  

  

  Experimental 
  Method. 
  — 
  Following 
  the 
  hint 
  given 
  by 
  Dr. 
  

   Stone, 
  the 
  pressures 
  were 
  taken 
  by 
  a 
  water-manometer 
  con- 
  

   nected 
  to 
  the 
  performer's 
  mouth 
  by 
  an 
  indiarubber 
  tube 
  

   terminating 
  in 
  a 
  glass 
  nozzle 
  which 
  could 
  be 
  held 
  by 
  the 
  

   side 
  teeth. 
  After 
  a 
  little 
  practice, 
  the 
  instrument 
  could 
  be 
  

   played 
  without 
  the 
  insertion 
  of 
  this 
  side 
  nozzle 
  producing 
  

   any 
  serious 
  annoyance. 
  The 
  open 
  end 
  of 
  the 
  manometer 
  

   was 
  provided 
  with 
  a 
  plug 
  of 
  cork 
  and 
  cotton-wool 
  which 
  

   just 
  damped 
  out 
  the 
  oscillations 
  of 
  the 
  water 
  columns 
  in 
  it 
  

   without 
  interfering 
  with 
  their 
  prompt 
  assumption 
  of 
  the 
  

   correct 
  levels 
  when 
  a 
  note 
  was 
  sounded. 
  To 
  arrest 
  the 
  

   columns 
  immediately 
  in 
  these 
  positions 
  and 
  retain 
  them 
  

   there 
  until 
  the 
  readings 
  were 
  taken, 
  a 
  pinch-cock 
  was 
  used 
  

   on 
  the 
  indiarubber 
  pipe 
  connecting 
  the 
  manometer 
  with 
  the 
  

   player's 
  mouth. 
  Thus 
  the 
  modus 
  operandi 
  was 
  as 
  follows: 
  — 
  

   A 
  series 
  of 
  notes 
  and 
  their 
  loudness 
  being 
  decided 
  upon 
  and 
  

   indicated 
  in 
  the 
  note-book 
  and 
  the 
  player 
  and 
  recorder 
  in 
  

   position, 
  the 
  recorder 
  calls 
  for 
  a 
  certain 
  note, 
  at 
  the 
  same 
  

   time 
  opening 
  the 
  pinch-cock. 
  The 
  player 
  sounds 
  the 
  note 
  

   and 
  sustains 
  it 
  till 
  it 
  is 
  judged 
  to 
  be 
  of 
  the 
  desired 
  intensity 
  ; 
  

   the 
  pinch-cock 
  is 
  then 
  released, 
  thus 
  immediately 
  closing 
  

  

  