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  Geological 
  Survey 
  of 
  Louisiana 
  [Sect. 
  

  

  A 
  REPORT 
  ON 
  LOUISIANA 
  CLAY 
  SAMPLES. 
  

   Preliminary 
  Remarks 
  

  

  IvOCALITlES 
  

  

  The 
  samples 
  examined 
  were 
  from 
  the 
  following 
  localities 
  : 
  

   Harris 
  No. 
  53. 
  Alluvial 
  clay, 
  R. 
  R. 
  track 
  just 
  S. 
  of 
  Little 
  R. 
  

   40. 
  Grand 
  Gulf 
  clay, 
  i 
  mile 
  west 
  of 
  Lena. 
  

   62. 
  Carter's 
  pottery 
  works, 
  Robelien, 
  La. 
  

   X. 
  Sec. 
  17, 
  3 
  N., 
  II 
  W. 
  

   St. 
  Joe 
  brick 
  cla5\ 
  

   Shale, 
  Sec. 
  17, 
  3 
  N., 
  11 
  W. 
  

  

  Explanation 
  of 
  Tests 
  

  

  Before 
  giving 
  the 
  results 
  of 
  the 
  tests 
  and 
  presenting 
  my 
  con- 
  

   clusions 
  concerning 
  the 
  possible 
  uses 
  of 
  the 
  material 
  investigated, 
  

   it 
  may 
  be 
  well 
  to 
  explain 
  the 
  tests 
  which 
  were 
  carried 
  out 
  on 
  the 
  

   sample, 
  and 
  their 
  practical 
  bearing. 
  

  

  Two 
  kinds 
  of 
  tests. 
  — 
  In 
  the 
  testing 
  of 
  clays, 
  two 
  different 
  lines 
  

   of 
  work 
  may 
  be 
  followed, 
  the 
  one 
  chemical 
  and 
  the 
  other 
  physi- 
  

   cal. 
  The 
  former 
  gives 
  results 
  that 
  are 
  of 
  practical 
  value 
  only 
  

   in 
  certain 
  cases 
  ; 
  the 
  latter 
  is 
  of 
  practical 
  importance 
  in 
  every 
  

   case, 
  and 
  yields 
  information 
  concerning 
  the 
  material 
  that 
  can 
  be 
  

   appreciated 
  and 
  used 
  by 
  the 
  intelligent 
  clay 
  worker. 
  It 
  is 
  the 
  

   physical 
  testing 
  that 
  has 
  been 
  done 
  on 
  the 
  samples 
  submitted. 
  

  

  Plasticity. 
  — 
  Clay 
  is 
  a 
  very 
  common 
  substance 
  in 
  nature, 
  and 
  

   yetnothwithstanding 
  its 
  abundance, 
  it 
  is 
  one 
  of 
  the 
  mineral 
  prod- 
  

   ucts 
  whose 
  properties 
  are 
  least 
  understood. 
  The 
  most 
  striking 
  

   property 
  that 
  clay 
  possesses 
  is 
  plasticit}^ 
  and 
  it 
  is 
  one 
  of 
  the 
  two 
  

   properties 
  that 
  make 
  it 
  of 
  such 
  enormous 
  value 
  to 
  mankind. 
  

   Plasticity 
  in 
  brief 
  is 
  the 
  property 
  by 
  virtue 
  of 
  which 
  the 
  clay 
  

   when 
  mixed 
  with 
  water 
  can 
  be 
  molded 
  into 
  any 
  desired 
  shape, 
  

   which 
  form 
  it 
  retains 
  when 
  dry. 
  The 
  second 
  great 
  property 
  is 
  

   brought 
  out 
  when 
  the 
  clay 
  is 
  subjected 
  to 
  a 
  degree 
  of 
  heat 
  above 
  

   low 
  redness, 
  it 
  becoming 
  converted 
  into 
  a 
  hard 
  rock-like 
  mass, 
  

   which 
  for 
  durability 
  and 
  strength 
  is 
  exceeded 
  by 
  few 
  building 
  

   stones. 
  

  

  