﻿452 
  F. 
  A. 
  G-ooch 
  and 
  T. 
  S 
  Hart 
  — 
  Detection 
  and 
  

  

  made 
  to 
  pick 
  up 
  a 
  drop 
  of 
  a 
  size 
  only 
  sufficient 
  to 
  fill 
  it 
  by 
  

   simply 
  touching 
  the 
  coil 
  while 
  hissing 
  hot 
  to 
  the 
  drop. 
  

  

  Certain 
  experiments 
  in 
  which 
  the 
  method 
  of 
  manipulation 
  

   which 
  we 
  have 
  described 
  was 
  applied 
  to 
  the 
  determination 
  of 
  

   potassium 
  salts 
  other 
  than 
  the 
  chloride 
  indicated 
  that 
  the 
  test 
  

   is 
  less 
  delicate 
  in 
  the 
  case 
  of 
  the 
  sulphate, 
  and 
  lather 
  more 
  

   delicate 
  in 
  the 
  case 
  of 
  the 
  carbonate. 
  We 
  were 
  able 
  to 
  find 
  

   the 
  red 
  line 
  of 
  potassium 
  unmistakably, 
  when 
  only 
  -g-oVo 
  °^ 
  a 
  

   milligram 
  of 
  potassium 
  was 
  introduced 
  into 
  the 
  flame 
  in 
  the 
  

   form 
  of 
  the 
  carbonate. 
  

  

  The 
  quantitative 
  determination 
  of 
  potassium 
  by 
  the 
  spectro- 
  

   scope 
  has 
  never, 
  so 
  far 
  as 
  we 
  know, 
  been 
  accomplished 
  heretofore. 
  

   Sodium 
  appears 
  to 
  have 
  been 
  successfully 
  estimated 
  by 
  Cham- 
  

   pion, 
  Pellet 
  and 
  Grenier* 
  by 
  the 
  use 
  of 
  comparison 
  flames, 
  

   produced 
  by 
  the 
  aid 
  of 
  complex 
  mechanism, 
  and 
  a 
  spectro- 
  

   photometer 
  of 
  original 
  construction. 
  Lithium 
  has 
  been 
  deter- 
  

   mined 
  more 
  simply, 
  Truchotf 
  having 
  been 
  the 
  first 
  to 
  suggest 
  

   a 
  method 
  of 
  manipulation 
  which 
  was 
  modified 
  by 
  BallraannJ 
  

   and 
  taken 
  up 
  later 
  by 
  Bell§ 
  apparently 
  without 
  knowledge 
  of 
  

   the 
  previous 
  work 
  on 
  the 
  same 
  line. 
  Truchot's 
  method 
  con- 
  

   sists 
  in 
  comparing 
  the 
  duration 
  and 
  strength 
  of 
  the 
  spectral 
  

   lines 
  developed 
  by 
  exposure 
  to 
  the 
  Bun 
  sen 
  flame 
  of 
  portions 
  

   taken 
  up 
  in 
  a 
  platinum 
  loop 
  from 
  the 
  test-solution 
  and 
  standard 
  

   solutions 
  of 
  different 
  strengths. 
  J^o 
  analytical 
  proofs 
  of 
  the 
  

   value 
  of 
  the 
  method 
  were 
  given 
  and 
  accuracy 
  was 
  not 
  claimed 
  

   beyond 
  the 
  recognition 
  of 
  differences 
  of 
  from 
  three 
  to 
  four 
  

   milligrams 
  in 
  a 
  liter 
  of 
  liquid 
  when 
  amounts 
  not 
  exceeding 
  

   forty 
  milligrams 
  per 
  liter 
  were 
  compared. 
  Ballmann 
  discards 
  

   as 
  valueless 
  the 
  observation 
  of 
  the 
  duration 
  of 
  the 
  spectral 
  

   line, 
  advocates 
  the 
  dilution 
  of 
  the 
  test 
  and 
  standard 
  solutions 
  

   to 
  the 
  absolute 
  extinction 
  of 
  the 
  line, 
  and 
  employs 
  hollow 
  

   cones, 
  measuring 
  2*5 
  mm 
  by 
  3*5 
  mm 
  , 
  to 
  carry 
  the 
  liquids 
  to 
  the 
  

   flame. 
  Bell 
  follows 
  Ballmann's 
  method 
  of 
  diluting 
  the 
  solu- 
  

   tions 
  to 
  be 
  compared 
  to 
  a 
  common 
  condition, 
  but 
  takes 
  the 
  

   vanishing 
  point 
  of 
  the 
  line 
  instead 
  of 
  the 
  point 
  of 
  absolute 
  

   invisibility 
  and 
  makes 
  his 
  loops 
  of 
  platinum 
  very 
  small. 
  Both 
  

   Ballmann 
  and 
  Bell 
  were 
  able 
  to 
  estimate 
  thallium 
  similarly, 
  

   but 
  neither 
  determined 
  potassium, 
  Bell 
  declaring 
  specifically 
  

   that 
  the 
  method 
  is 
  inapplicable 
  to 
  the 
  handling 
  of 
  that 
  ele- 
  

   ment. 
  

  

  Our 
  success 
  in 
  determining 
  potassium 
  qualitatively 
  by 
  the 
  

   use 
  of 
  powerful 
  flames 
  and 
  coils 
  of 
  large 
  dimensions 
  was 
  such 
  

   as 
  to 
  encourage 
  the 
  attempt 
  to 
  apply 
  quantitatively 
  the 
  same 
  

   method 
  of 
  manipulating; 
  and 
  from 
  certain 
  preliminary 
  experi- 
  

  

  *Compt. 
  Rend., 
  lxxvi, 
  707. 
  f 
  Compt. 
  Rend., 
  lxxviii, 
  1022. 
  

  

  \ 
  Zeitsehr. 
  fur 
  Anal. 
  Cliem., 
  xiv, 
  297. 
  § 
  Am. 
  Chem. 
  Jour., 
  vii, 
  35. 
  

  

  