﻿Thomson.- 
  — 
  On 
  the 
  Cleansing 
  of 
  Towns. 
  67 
  

  

  Drs. 
  Letheby 
  and 
  Williamson 
  of 
  the 
  soU 
  of 
  its 
  bed, 
  both 
  in 
  Woolwich 
  Eeach 
  

   and 
  near 
  to 
  the 
  sewage 
  outfalls 
  ; 
  and 
  to 
  give 
  his 
  consideration 
  to 
  the 
  changes 
  

   thus 
  shown 
  to 
  have 
  taken 
  place 
  in 
  the 
  channel 
  of 
  the 
  river, 
  and 
  in 
  the 
  

   character 
  of 
  its 
  bottom, 
  for 
  the 
  purpose 
  of 
  reporting 
  thereon. 
  Captain 
  

   Calver 
  adds, 
  that 
  from 
  the 
  time 
  of 
  receiving 
  the 
  foregoing 
  uistructions, 
  

   he 
  had 
  been 
  engaged 
  upon 
  the 
  various 
  details 
  of 
  investigation, 
  including, 
  

   amongst 
  other 
  things, 
  repeated 
  observations 
  upon 
  the 
  movements 
  of 
  the 
  

   streams 
  in 
  the 
  central 
  section 
  of 
  the 
  Thames, 
  with 
  the 
  collection 
  of 
  such 
  

   other 
  physical 
  facts 
  as 
  were 
  likely 
  to 
  aid 
  him 
  in 
  arriving 
  at 
  a 
  clear 
  under- 
  

   standing 
  of 
  this 
  important 
  and 
  interesting 
  case*. 
  

  

  From 
  his 
  report 
  we 
  shall 
  make 
  extracts, 
  noticing 
  the 
  salient 
  points 
  

   of 
  interest. 
  He 
  states 
  " 
  that 
  the 
  general 
  features 
  of 
  Mid-Thames, 
  its 
  

   sectional 
  capacity, 
  and 
  the 
  various 
  details 
  of 
  increase 
  and 
  decrease, 
  are 
  

   aU 
  brought 
  out 
  very 
  clearly 
  in 
  the 
  surveys 
  made 
  by 
  the 
  order 
  of 
  the 
  Board. 
  

   This 
  series 
  — 
  the 
  work 
  of 
  the 
  same 
  observers, 
  and 
  all 
  referable 
  to 
  a 
  common 
  

   standard 
  — 
  has 
  been 
  made 
  between 
  1861 
  and 
  1876." 
  

  

  Again 
  : 
  " 
  It 
  having 
  been 
  reported 
  in 
  1867 
  that 
  a 
  vessel 
  had 
  unexpectedly 
  

   touched 
  the 
  ground 
  while 
  passing 
  the 
  southern 
  outfall, 
  a 
  new 
  survey 
  was 
  

   ordered 
  to 
  be 
  made 
  for 
  the 
  locality." 
  

  

  Again: 
  " 
  1832 
  to 
  1861, 
  a 
  considerable 
  increase 
  in 
  the 
  general 
  capacity 
  

   of 
  the 
  channel 
  occurred 
  in 
  the 
  foregoing 
  period 
  — 
  the 
  result 
  of 
  dredging, 
  for 
  

   the 
  most 
  part." 
  

  

  Again 
  : 
  " 
  1863 
  and 
  1864, 
  sewage 
  began 
  to 
  be 
  discharged 
  from 
  the 
  out- 
  

   faUs." 
  

  

  Again: 
  " 
  Since 
  the 
  Metropolitan 
  outfalls 
  came 
  into 
  operation, 
  the 
  former 
  

   deep 
  and 
  free 
  frontage 
  of 
  the 
  southernmost 
  one 
  has 
  lost 
  a 
  quarter 
  part 
  of 
  its 
  

   loiv 
  water 
  contents.'" 
  Again: 
  "that 
  the 
  upper 
  part 
  of 
  the 
  river 
  has 
  been 
  

   troubled 
  with 
  accumulations, 
  which, 
  as 
  will 
  be 
  shown, 
  must 
  necessai-ily 
  have 
  

   been 
  conveyed 
  upwards 
  by 
  the 
  flood-stream.'' 
  

  

  In 
  the 
  analyses 
  made, 
  " 
  the 
  mud 
  in 
  each 
  case 
  was 
  black 
  and 
  fetid 
  in 
  a 
  

   state 
  of 
  active 
  putrefactive 
  decomposition, 
  and, 
  when 
  examined 
  under 
  the 
  

   microscope, 
  it 
  was 
  found 
  to 
  consist 
  of 
  broken-up 
  sewage 
  matter." 
  Of 
  the 
  

   water, 
  when 
  near 
  Woolwich, 
  Greenwich 
  and 
  London 
  Bridge, 
  " 
  all 
  the 
  

   samples 
  were 
  black 
  and 
  offensive, 
  and 
  they 
  were 
  found, 
  on 
  examination 
  

   under 
  the 
  microscope, 
  to 
  consist 
  of 
  amorphous 
  matter 
  of 
  the 
  disintegrated 
  

   tissue 
  of 
  vegetables, 
  especially 
  of 
  wheat, 
  and 
  swarms 
  of 
  diatomaceous 
  re- 
  

   mains." 
  Again 
  : 
  in 
  the 
  last 
  test 
  of 
  1875, 
  " 
  most 
  of 
  the 
  samples 
  demonstrated 
  

   the 
  presence 
  of 
  sewage 
  matter 
  in 
  a 
  state 
  of 
  decomposition." 
  Those 
  from 
  " 
  the 
  

   GalUon 
  Eeach, 
  withiu 
  the 
  influence 
  of 
  the 
  northern 
  outfall, 
  exhibited 
  

   organic 
  and 
  other 
  similar 
  matter 
  to 
  those 
  of 
  street-mud, 
  while 
  others 
  in 
  the 
  

  

  * 
  Report, 
  16th 
  October, 
  1877. 
  

  

  