﻿870 
  

  

  Mr. 
  B.TV. 
  Clack 
  on 
  the 
  

  

  late, 
  but 
  slowly 
  takes 
  up 
  its 
  new 
  position. 
  The 
  consistency 
  

   obtained 
  under 
  these 
  static 
  conditions 
  was 
  tested, 
  and 
  the 
  

   following 
  is 
  a 
  sample 
  of 
  the 
  figures 
  obtained 
  : 
  — 
  

  

  

  37-104 
  

  

  37-103 
  

  

  37105 
  

  

  

  Resting 
  Point 
  observed 
  ... 
  10*2 
  

  

  Repeated. 
  

   Resting 
  Point 
  observed 
  ... 
  10*0 
  

  

  11-9 
  

  

  12-0 
  

  

  13-5 
  

   13-9 
  

  

  100 
  

   10-2 
  

  

  Moreover, 
  it 
  was 
  found 
  that 
  the 
  position 
  of 
  the 
  pointer 
  

   remained 
  con-taut 
  to 
  within 
  1 
  scale-division 
  for 
  a 
  week, 
  the 
  

   temperature 
  being 
  meanwhile 
  kept 
  at 
  0° 
  0. 
  by 
  the 
  surrounding 
  

   ice-jacket. 
  

  

  The 
  sensitiveness 
  of 
  the 
  balance 
  under 
  the 
  actual 
  conditions 
  

   holding 
  in 
  a 
  diffusion 
  experiment 
  was 
  found 
  from 
  a 
  large 
  

   number 
  of 
  reading- 
  to 
  be 
  '00052 
  gm. 
  per 
  scale-division, 
  i. 
  e. 
  

   a 
  movement 
  of 
  1 
  scale-division 
  in 
  the 
  resting 
  point 
  was 
  pro- 
  

   duced 
  by 
  "00052 
  gm. 
  

  

  ."). 
  Determination 
  of 
  the 
  Concentration. 
  

  

  Sodium 
  chloride 
  and 
  potassium 
  chloride 
  prepared 
  by 
  

   Kahlbaum, 
  of 
  Berlin, 
  were 
  the 
  first 
  salts 
  experimented 
  upon. 
  

   Solutions 
  were 
  prepared 
  of 
  approximately 
  0'2 
  gm., 
  0*1 
  gm., 
  

   and 
  0*05 
  gm. 
  of 
  salt 
  per 
  c.c. 
  of 
  the 
  solution, 
  and 
  in 
  each 
  case 
  

   a 
  check 
  experiment 
  was 
  carried 
  out 
  to 
  ensure 
  experimental 
  

   consistency. 
  The 
  concentration 
  of 
  these 
  solutions 
  was 
  deter- 
  

   mined 
  in 
  most 
  cases 
  by 
  three 
  different 
  methods: 
  (1) 
  From 
  

   the 
  density, 
  making 
  use 
  of 
  the 
  results 
  given 
  in 
  the 
  Phjsikalisch- 
  

   ('hcmisclie 
  Tabellen, 
  published 
  by 
  Landolt 
  and 
  Bornstein 
  ; 
  

   (2) 
  Precipitation 
  by 
  AgN0 
  3 
  ; 
  (3) 
  Evaporation 
  to 
  dryness 
  

   in 
  a 
  platinum 
  crucible. 
  

  

  The 
  results 
  obtained 
  by 
  all 
  three 
  methods 
  usually 
  agreed 
  

   to 
  within 
  less 
  than 
  1 
  per 
  cent., 
  as 
  the 
  following 
  figures 
  will 
  

   show 
  : 
  — 
  

  

  Values 
  of 
  N 
  in 
  gins, 
  of 
  KC1 
  per 
  c.c. 
  of 
  Solution 
  at 
  0° 
  C. 
  

  

  Solution 
  

  

  2. 
  3. 
  4. 
  

  

  5. 
  

  

  0. 
  

  

  7. 
  

  

  By 
  Density 
  

  

  By 
  Precipitation 
  ... 
  

   By 
  Evaporation 
  ... 
  

  

  Mean 
  

  

  •19D0 
  -1009 
  -1004 
  

   •1989 
  ... 
  1004 
  

   •1968 
  -1008 
  -1004 
  

  

  •05122 
  

   •05128 
  

   ■05100 
  

  

  •05147 
  

   •05106 
  

   •05097 
  

  

  •05106 
  

   •05092 
  

   05113 
  

  

  •05104 
  

  

  •1989 
  -1008 
  

  

  •1004 
  

  

  •05117 
  

  

  •05117 
  

  

  