﻿412 
  A. 
  W. 
  Duff- 
  — 
  Seiches 
  on 
  the 
  Bay 
  of 
  Fundy. 
  

  

  undulations 
  " 
  exist 
  at 
  St. 
  John, 
  to 
  be 
  able 
  to 
  obtain 
  a 
  record 
  

   near 
  Digby 
  by 
  use 
  of 
  a 
  small 
  portable 
  gauge. 
  

  

  If 
  the 
  preceding 
  explanation 
  of 
  " 
  secondary 
  undulations 
  " 
  

   prove 
  correct, 
  it 
  will 
  be 
  a 
  question 
  of 
  interest 
  why 
  the 
  undula- 
  

   tions 
  here 
  treated 
  of 
  are 
  trinodal, 
  while 
  those 
  of 
  the 
  lakes 
  

   observed 
  by 
  Forel 
  are 
  chiefly 
  binodal. 
  No 
  light 
  seems 
  thrown 
  

   on 
  the 
  question 
  by 
  present 
  hydrodynamical 
  theory. 
  The 
  

   explanation 
  may 
  perhaps 
  be 
  found 
  in 
  the 
  fact 
  that 
  a 
  lake 
  is 
  a 
  

   completely 
  enclosed 
  body 
  of 
  water, 
  while 
  a 
  bay 
  is 
  open 
  at 
  one 
  

   side 
  or 
  two 
  opposite 
  sides. 
  If, 
  as 
  seems 
  possible, 
  the 
  smaller 
  

   undulations 
  across 
  the 
  basin 
  at 
  Indiantown 
  are 
  produced 
  in 
  

   some 
  way 
  by 
  the 
  larger 
  ones 
  of 
  the 
  harbor 
  entering 
  at 
  one 
  end 
  

   of 
  the 
  small 
  bay, 
  the 
  result 
  would 
  more 
  probably 
  be 
  a 
  simulta- 
  

   neous 
  elevation 
  at 
  opposite 
  sides 
  than 
  an 
  elevation 
  at 
  one 
  and 
  

   a 
  depression 
  at 
  the 
  other. 
  This 
  suggests 
  that 
  the 
  undulations 
  

   across 
  the 
  Bay 
  of 
  Fundy 
  may 
  in 
  some 
  similar 
  way 
  be 
  produced 
  

   by 
  the 
  uprush 
  or 
  downrush 
  of 
  the 
  tides. 
  They 
  do 
  not 
  seem 
  (as 
  

   in 
  the 
  case 
  of 
  the 
  Swiss 
  seiches) 
  to 
  be 
  connected 
  with 
  abnormal 
  

   conditions 
  of 
  barometer 
  ; 
  at 
  least 
  no 
  such 
  connection 
  appears 
  

   to 
  exist 
  in 
  the 
  cases 
  whose 
  periods 
  are 
  given 
  above. 
  

  

  Addendum. 
  In 
  a 
  recent 
  article 
  (Phil. 
  Mag., 
  Jan. 
  1897), 
  

   Mr. 
  C. 
  Davison 
  has 
  pointed 
  out 
  that 
  a 
  considerable 
  error 
  may 
  

   be 
  made 
  in 
  extending 
  the 
  formula 
  for 
  a 
  basin 
  of 
  uniform 
  depth 
  

   to 
  one 
  of 
  irregular 
  depth. 
  In 
  fact 
  the 
  true 
  period 
  of 
  the 
  tri- 
  

   nodal 
  vibrations 
  considered 
  in 
  the 
  preceding 
  is 
  

  

  / 
  

  

  -— 
  , 
  (y 
  = 
  depth), 
  

  

  Vf/y 
  

  

  Changing 
  this 
  to 
  the 
  form 
  

  

  — 
  X 
  (mean 
  — 
  — 
  ) 
  , 
  

  

  Vff 
  x 
  vyi 
  

  

  I 
  have 
  calculated 
  its 
  value 
  for 
  trinodal 
  vibrations 
  across 
  the 
  

   Bay 
  of 
  Fundy, 
  at 
  St. 
  John 
  (allowing 
  two 
  miles 
  as 
  before) 
  and 
  

   find 
  that 
  it 
  gives 
  a 
  period 
  of 
  42*2 
  minutes. 
  

   Purdue 
  University, 
  Lafayette, 
  Ind. 
  

  

  