﻿Lord 
  Rayleigh 
  : 
  Acoustical 
  Notes. 
  239 
  

  

  •of 
  drops, 
  the 
  distance 
  between 
  the 
  drops, 
  or 
  the 
  number 
  of 
  

   drops 
  passing 
  a 
  given 
  point 
  in 
  unit 
  time, 
  depending 
  upon 
  the 
  

   diameter 
  and 
  velocity 
  of 
  the 
  jet, 
  When 
  a 
  jet, 
  otherwise 
  

   undisturbed, 
  is 
  under 
  the 
  influeuce 
  of 
  a 
  regular 
  vibrator 
  of 
  

   suitable 
  pitch, 
  the 
  resolution 
  becomes 
  absolutely 
  uniform 
  and 
  

   takes 
  its 
  frequency 
  from 
  the 
  vibrator*. 
  If 
  the 
  procession 
  of 
  

   drops 
  thus 
  regularized 
  is 
  caused 
  to 
  strike 
  a 
  second 
  vibrator 
  

   of 
  like 
  pitch, 
  the 
  latter 
  will 
  usually 
  be 
  excited. 
  The 
  arrange- 
  

   ment 
  is 
  simplified 
  and 
  any 
  question 
  of 
  insufficient 
  agreement 
  

   of 
  pitch 
  is 
  eliminated, 
  if 
  both 
  parts 
  be 
  assigned 
  to 
  the 
  same 
  

   vibrator 
  which 
  at 
  once 
  regularises 
  the 
  resolution 
  of 
  the 
  jet 
  

   and 
  is 
  itself 
  maintained 
  in 
  vibration 
  by 
  the 
  impact 
  of 
  the 
  

   drops. 
  

  

  The 
  experiment 
  has 
  been 
  tried 
  with 
  tuning-forks 
  of 
  pitch 
  

   256 
  and 
  320. 
  The 
  reaction 
  between 
  the 
  fork 
  A 
  and 
  the 
  jet 
  

   issuing 
  at 
  B 
  (fig. 
  1) 
  is 
  effected 
  through 
  a 
  branch 
  tubs 
  E 
  

  

  Fi 
  2 
  -. 
  l. 
  

  

  ~\ 
  f 
  

  

  terminating 
  in 
  a 
  metal 
  box 
  D. 
  The 
  box 
  is 
  provided 
  with 
  a 
  

   wooden 
  socket 
  cemented 
  on 
  a 
  flexible 
  face, 
  to 
  which 
  the 
  fork 
  

   is 
  screwed. 
  The 
  vibrations 
  of 
  the 
  fork, 
  transmitted 
  through 
  

   its 
  stalk, 
  cause 
  the 
  flow 
  at 
  B 
  to 
  be 
  slightly 
  variable, 
  and 
  if 
  

   the 
  adjustments 
  are 
  suitable 
  determine 
  a 
  stream 
  of 
  drops 
  of 
  

   the 
  same 
  frequency. 
  The 
  orifice 
  at 
  B, 
  perforated 
  in 
  a 
  thin 
  

   metal 
  plate, 
  is 
  of 
  about 
  2 
  mm. 
  diameter. 
  The 
  tubes 
  are 
  of 
  

   lead, 
  allowing 
  slight 
  adjustments 
  by 
  bending 
  ; 
  the 
  supply 
  

  

  * 
  The 
  theory 
  of 
  these 
  effects, 
  on 
  lines 
  roughly 
  sketched 
  by 
  Savart 
  and 
  

   Plateau, 
  is 
  given 
  in 
  Proc. 
  Roy. 
  Soc. 
  xxix. 
  p. 
  71, 
  1879; 
  Scientific 
  Papers, 
  

   i. 
  p. 
  377 
  ; 
  or 
  ' 
  Theory 
  of 
  Sound,' 
  2nd 
  edition, 
  ii. 
  p. 
  362. 
  

  

  