﻿238 
  Lord 
  Rayleigh 
  : 
  Acoustical 
  Notes. 
  

  

  the 
  pitch 
  is 
  lowered 
  relatively 
  to 
  the 
  normal. 
  On 
  the 
  other 
  

   hand 
  it 
  appeared, 
  rather 
  to 
  my 
  surprise, 
  that 
  a 
  lowering 
  of 
  

   the 
  bellows 
  pressure 
  (sometimes 
  convenient 
  in 
  order 
  to 
  

   diminish 
  the 
  intensity 
  of 
  sound) 
  slightly 
  raises 
  the 
  pitch. 
  

  

  When 
  the 
  loads 
  of 
  wax 
  were 
  all 
  removed, 
  the 
  first 
  partial 
  

   tone 
  rose 
  nearly 
  an 
  octave, 
  indicating 
  that 
  the 
  loading 
  had 
  

   been 
  very 
  severe. 
  

  

  In 
  a 
  second 
  experiment 
  the 
  loads 
  were 
  reduced 
  to 
  less 
  

   than 
  half, 
  the 
  unit 
  being 
  taken 
  equal 
  to 
  0*1 
  gm., 
  the 
  distri- 
  

   bution 
  of 
  the 
  loads 
  and 
  the 
  length 
  of 
  the 
  wire 
  being 
  as 
  before. 
  

   Comparisons, 
  either 
  directly 
  with 
  the 
  harmonium 
  or 
  with 
  

   forks 
  as 
  intermediaries, 
  gave 
  the 
  following 
  results. 
  The 
  

   second 
  partial 
  of 
  the 
  wire 
  was 
  5 
  beats 
  per 
  second 
  flat 
  on 
  (the 
  

   octave 
  overtone 
  of) 
  harmonium 
  B. 
  The 
  third 
  partial 
  was 
  

   4 
  beats 
  per 
  second 
  flat 
  on 
  the 
  corresponding 
  partial 
  of 
  E. 
  

   The 
  fourth 
  partial 
  was 
  2 
  beats 
  flat 
  on 
  B, 
  and 
  the 
  fifth 
  partial 
  

   was 
  2 
  beats 
  sharp 
  on 
  B. 
  If 
  we 
  regard 
  the 
  two 
  last 
  partials 
  

   as 
  in 
  tune 
  with 
  B, 
  the 
  second 
  partial 
  is 
  out 
  by 
  5 
  vibrations 
  

   in 
  about 
  256, 
  or 
  one 
  in 
  55, 
  Adz. 
  between 
  a 
  third 
  and 
  a 
  quarter 
  

   of 
  a 
  semitone. 
  The 
  first 
  partial 
  of 
  the 
  loaded 
  wire 
  was 
  

   almost 
  exactly 
  two 
  semitones 
  below 
  harmonium 
  B. 
  

  

  I 
  had 
  supposed 
  that 
  the 
  small 
  deviations 
  from 
  harmonic 
  

   relations 
  exhibited 
  by 
  the 
  second 
  and 
  higher 
  partials 
  might 
  

   be 
  due 
  to 
  the 
  discontinuity 
  of 
  the 
  loading 
  or 
  to 
  the 
  fact 
  that 
  

   the 
  loads 
  were 
  not 
  sufficiently 
  concentrated 
  upon 
  the 
  line 
  of 
  

   the 
  wire. 
  But 
  subsequent 
  observations 
  upon 
  an 
  unloaded 
  

   wire 
  showed 
  very 
  similar 
  deviations. 
  The 
  length 
  was 
  the 
  

   same 
  but 
  the 
  tension 
  was 
  diminished 
  so 
  as 
  to 
  bring 
  the 
  pitch 
  

   back 
  to 
  B. 
  The 
  first 
  partial 
  of 
  the 
  wire 
  was 
  now 
  one 
  per 
  

   second 
  flat, 
  the 
  second 
  1J 
  per 
  second 
  flat, 
  the 
  third 
  2 
  per 
  

   second 
  flat, 
  the 
  fourth 
  1 
  per 
  second 
  sharp, 
  the 
  fifth 
  3^ 
  per 
  

   second 
  sharp, 
  and 
  the 
  sixth 
  about 
  8 
  per 
  second 
  sharp, 
  all 
  

   referred 
  to 
  the 
  corresponding 
  partials 
  of 
  harmonium 
  B. 
  

   Since 
  the 
  partials 
  of 
  the 
  harmonium 
  note 
  are 
  necessarily 
  in 
  

   tune, 
  harmonic 
  relations 
  among 
  the 
  partials 
  of 
  the 
  wire 
  

   would 
  require 
  beats 
  always 
  upon 
  the 
  same 
  side 
  and 
  numeri- 
  

   cally 
  as 
  the 
  natural 
  numbers 
  1, 
  2, 
  3. 
  1. 
  5, 
  6. 
  It 
  may 
  he 
  

   noted 
  that 
  the 
  wooden 
  bridges, 
  by 
  which 
  the 
  vibrating 
  

   portion 
  of 
  the 
  wire 
  was 
  limited, 
  wore 
  provided 
  above 
  and 
  

   below 
  with 
  sharp 
  edges, 
  and 
  were 
  free 
  to 
  turn. 
  In 
  this 
  way 
  

   the 
  vibrating 
  portion 
  was 
  well 
  defined, 
  and 
  the 
  tension 
  (due 
  

   to 
  weights 
  hung 
  over 
  a 
  pulley) 
  was 
  freely 
  transmitted. 
  

  

  Maintenance 
  of' 
  Vibrations 
  by 
  Impact 
  of 
  Water 
  Drops* 
  

  

  It 
  is 
  known 
  that 
  jet- 
  of 
  liquid 
  tend 
  to 
  resolve 
  themselves 
  

   under 
  capillary 
  force 
  into 
  more 
  or 
  !c-s 
  uniform 
  processions 
  

  

  