﻿Chemistry 
  and 
  Physics. 
  213 
  

  

  tion 
  is 
  formed 
  whenever 
  carbon 
  is 
  deposited 
  by 
  chemical 
  or 
  

   thermal 
  decomposition 
  of 
  carbon-bearing 
  materials 
  at 
  relatively 
  

   low 
  temperatures, 
  generally 
  below 
  500 
  to 
  600° 
  C, 
  while 
  the 
  

   inactive 
  form 
  results 
  from 
  similar 
  decompositions 
  above 
  this 
  

   temperature. 
  The 
  active 
  carbon 
  may 
  adsorb 
  hydrocarbons 
  

   immediately 
  after 
  its 
  formation 
  so 
  that 
  its 
  power 
  for 
  combining 
  

   with 
  other 
  substances 
  is 
  lessened, 
  but 
  it 
  is 
  possible 
  to 
  activate 
  

   such 
  a 
  product 
  by 
  removing 
  the 
  hydrocarbons 
  by 
  distillation 
  in 
  

   presence 
  of 
  air, 
  steam, 
  or 
  carbon 
  dioxide 
  at 
  low 
  temperatures, 
  

   for 
  instance 
  in 
  air 
  at 
  300° 
  C. 
  It 
  is 
  interesting 
  to 
  know 
  that 
  

   anthracite 
  and 
  bituminous 
  coal 
  contain 
  the 
  active 
  form 
  of 
  car- 
  

   bon, 
  and 
  that 
  it 
  may 
  be 
  prepared 
  from 
  these 
  sources 
  by 
  the 
  pro- 
  

   cesses 
  of 
  activation 
  just 
  mentioned. 
  The 
  author 
  says 
  that 
  the 
  

   unique 
  properties 
  of 
  this 
  material, 
  both 
  as 
  a 
  catalyst 
  and 
  adsorb- 
  

   ent 
  suggest 
  that 
  it 
  will 
  find 
  many 
  industrial 
  applications. 
  — 
  ■ 
  

   Canadian 
  Chem. 
  Jour., 
  3, 
  No. 
  11. 
  h. 
  l. 
  w. 
  

  

  3. 
  On 
  the 
  Sulphite 
  Method 
  for 
  the 
  Separation 
  and 
  Determi- 
  

   nation 
  of 
  Gallium 
  when 
  Associated 
  ivith 
  Zinc. 
  — 
  Lyman 
  E. 
  

   Porter 
  and 
  Philip 
  E. 
  Browning 
  have 
  applied 
  hydrogen 
  sodium 
  

   sulphite 
  and 
  hydrogen 
  ammonium 
  sulphite 
  for 
  the 
  qualitative 
  

   and 
  quantitative 
  separation 
  of 
  gallium 
  from 
  moderate 
  amounts 
  

   of 
  zinc. 
  For 
  the 
  qualitative 
  tests 
  about 
  5 
  cc. 
  of 
  the 
  neutral 
  or 
  

   slightly 
  acid 
  solution 
  was 
  boiled 
  for 
  two 
  minutes 
  after 
  the 
  addi- 
  

   tion 
  of 
  sodium 
  sulphite. 
  The 
  precipitate 
  indicating 
  gallium 
  is 
  

   filtered 
  off 
  after 
  settling 
  and 
  hydrochloric 
  acid 
  is 
  added 
  to 
  the 
  

   filtrate, 
  followed 
  by 
  potassium 
  ferrocyanide, 
  when 
  a 
  precipitate 
  

   indicates 
  zinc. 
  Under 
  these 
  conditions 
  as 
  little 
  as 
  0-0002 
  g. 
  of 
  

   gallium 
  and 
  00003 
  g. 
  of 
  zinc 
  could 
  be 
  detected, 
  either 
  when 
  one 
  

   was 
  absent 
  or 
  both 
  present. 
  The 
  method 
  was 
  found 
  to 
  be 
  satis- 
  

   factory 
  for 
  quantitative 
  work 
  on 
  account 
  of 
  the 
  granular 
  nature 
  

   of 
  the 
  precipitate. 
  It 
  is 
  convenient 
  to 
  precipitate 
  the 
  gallium 
  

   in 
  a 
  volume 
  of 
  about 
  200 
  cc. 
  of 
  neutral 
  or 
  slightly 
  acid 
  solution 
  

   by 
  adding 
  4 
  or 
  5 
  cc. 
  of 
  hydrogen 
  ammonium 
  sulphite 
  (made 
  by 
  

   saturating 
  1:4 
  ammonia 
  solution 
  with 
  S0 
  2 
  ) 
  boiling 
  for 
  from 
  3 
  

   to 
  5 
  minutes, 
  allowing 
  the 
  precipitate 
  to 
  settle, 
  decanting 
  the 
  

   supernatant 
  liquid 
  through 
  a 
  filter, 
  dissolving 
  the 
  precipitate 
  

   left 
  in 
  the 
  beaker 
  with 
  a 
  few 
  drops 
  of 
  hydrochloric 
  acid, 
  then, 
  

   after 
  adding 
  about 
  200 
  cc. 
  of 
  water 
  repeating 
  the 
  precipitation, 
  

   and 
  filtering 
  off 
  on 
  the 
  original 
  paper. 
  The 
  method 
  of 
  washing 
  

   is 
  not 
  described, 
  but 
  the 
  precipitate 
  is 
  ignited 
  and 
  weighed 
  as 
  

   Ga 
  2 
  3 
  . 
  The 
  results 
  of 
  the 
  test 
  analyses, 
  some 
  of 
  them 
  made 
  in 
  

   the 
  presence 
  of 
  0-1 
  to 
  0-35 
  g. 
  of 
  zinc 
  chloride, 
  show 
  remarkably 
  

   close 
  results 
  on 
  quantities 
  of 
  gallium 
  oxide 
  varying 
  from 
  0015 
  

   to 
  0047 
  g. 
  — 
  Jour. 
  Amer. 
  Chem. 
  Soc, 
  41, 
  1491. 
  h. 
  l. 
  w. 
  

  

  4. 
  The 
  Spectra 
  of 
  Isotropic 
  Lead 
  and 
  Thallium. 
  — 
  In 
  a 
  

   recent 
  communication 
  before 
  the 
  Royal 
  Society 
  it 
  was 
  stated 
  by 
  

   T. 
  R. 
  Merton 
  that 
  interferometer 
  measurements 
  of 
  the 
  prin- 
  

   cipal 
  line 
  in 
  the 
  spectra 
  of 
  ordinary 
  lead 
  and 
  of 
  lead 
  from 
  

  

  