﻿144 
  Transactions. 
  — 
  Miscellaneous. 
  

  

  liresent. 
  It 
  is 
  probable 
  that 
  measures 
  taken 
  now 
  with 
  the 
  improved 
  position 
  

   circle 
  and 
  the 
  clepsydra, 
  will 
  at 
  all 
  events 
  approach 
  in 
  accuracy 
  the 
  best 
  

   measures 
  taken 
  with 
  perfect 
  appliances. 
  If 
  mercury 
  could 
  be 
  used 
  instead 
  

   of 
  water 
  with 
  similar 
  apparatus, 
  still 
  better 
  results 
  would 
  be 
  obtained, 
  but 
  

   as 
  the 
  object 
  has 
  been 
  to 
  incur 
  as 
  little 
  expense 
  as 
  possible, 
  it 
  has 
  been 
  

   thought 
  advisable 
  to 
  adapt 
  the 
  arrangements 
  to 
  the 
  use 
  of 
  water. 
  

  

  It 
  is 
  obvious 
  that 
  this 
  method 
  is 
  available 
  for 
  measuring 
  the 
  diameter 
  

   of 
  planets, 
  sun-spots, 
  etc., 
  and 
  also 
  for 
  selenographical 
  observations. 
  

  

  Aet. 
  XI. 
  — 
  Deflection 
  of 
  Shingle-bearing 
  Currents 
  and 
  Protection 
  of 
  River 
  

   Banks 
  by 
  Druslhi's 
  Floating 
  Log 
  Dams. 
  By 
  H. 
  P. 
  Macklin. 
  

  

  Plate 
  II. 
  

   [Read 
  before 
  the 
  Wellington 
  Philosophical 
  Society, 
  11th 
  August, 
  1878.] 
  

   The 
  plain 
  of 
  the 
  Wairau 
  in 
  the 
  Province 
  of 
  Marlborough 
  is 
  a 
  tract 
  of 
  flat 
  

   alluvial 
  country, 
  averaging 
  about 
  ten 
  miles 
  by 
  seventy, 
  and 
  has 
  been 
  

   formed 
  on 
  the 
  channel 
  of 
  an 
  ancient 
  iceberg 
  (mer-de-glace), 
  by 
  the 
  streams 
  

   from 
  the 
  surrounding 
  hills 
  and 
  the 
  Wairau 
  Kiver, 
  which 
  traverses 
  its 
  

   entire 
  length, 
  rising 
  on 
  Mount 
  Mackay, 
  and 
  debouching 
  in 
  Cloudy 
  Bay, 
  a 
  

   portion 
  of 
  Cook 
  Strait. 
  Geologically 
  the 
  plain 
  is 
  of 
  post-pliocene 
  formation, 
  

   surrounded 
  towards 
  the 
  north 
  and 
  west 
  by 
  mountains 
  of 
  metamorphic 
  and 
  

   palaeozoic 
  origin, 
  and 
  on 
  the 
  south 
  by 
  low 
  hiUs 
  of 
  marine 
  tertiary 
  drift. 
  

  

  The 
  Wairau 
  Eiver 
  has 
  evidently 
  formed 
  the 
  greater 
  portion 
  of 
  the 
  plain, 
  

   and 
  carries 
  with 
  it 
  immense 
  quantities 
  of 
  shingle, 
  of 
  which 
  it 
  is 
  made 
  the 
  

   receptacle, 
  by 
  the 
  rivulets 
  from 
  the 
  hills. 
  'The 
  district 
  is 
  a 
  prosperous 
  

   farming 
  one 
  ; 
  and 
  from 
  its 
  first 
  settlement, 
  has 
  been 
  liable 
  to 
  considerable 
  

   damage, 
  not 
  only 
  from 
  the 
  flood-water 
  itself, 
  but 
  also 
  from 
  the 
  shifting 
  of 
  

   the 
  river-bed, 
  and 
  the 
  deposit 
  of 
  shingle 
  on 
  the 
  adjacent 
  lands. 
  The 
  town 
  

   of 
  Blenheim 
  is 
  situated 
  on 
  the 
  middle 
  of 
  the 
  plain, 
  and 
  unfortunately, 
  its 
  

   site 
  is 
  lower 
  by 
  several 
  feet 
  than 
  the 
  surrounding 
  country. 
  Every 
  year 
  its 
  

   danger 
  is 
  becoming 
  more 
  imminent, 
  as 
  the 
  beds 
  of 
  the 
  river 
  and 
  its 
  branch, 
  

   the 
  Opawa, 
  are 
  gradually 
  rising, 
  from 
  these 
  rivers 
  being 
  compelled 
  to 
  deposit 
  

   the 
  drift 
  on 
  their 
  banks 
  and 
  beds 
  by 
  lateral 
  embankments. 
  The 
  late 
  

   Provincial 
  Government, 
  under 
  the 
  direction 
  of 
  eminent 
  engineers, 
  has 
  

   tried 
  in 
  vain 
  many 
  devices 
  to 
  direct 
  the 
  stream 
  from 
  the 
  town. 
  All 
  were 
  

   unavailing, 
  as 
  the 
  rapidity 
  of 
  the 
  current 
  undermined 
  cratings, 
  tanks, 
  and 
  

   wing-walls, 
  while 
  the 
  enormous 
  quantities 
  of 
  shingle 
  deposited 
  defied 
  all 
  

   control. 
  Not 
  a 
  wreck 
  remains 
  of 
  all 
  the 
  works 
  thus 
  erected, 
  costing 
  some 
  

   jei5,000. 
  On 
  plan 
  No. 
  1 
  will 
  be 
  seen, 
  at 
  the 
  point 
  X, 
  the 
  lowest 
  point 
  in 
  

   the 
  river 
  bank, 
  whence 
  the 
  town 
  gets 
  flooded 
  by 
  overflow, 
  and 
  where 
  ths 
  

  

  