﻿Chemistry 
  and 
  Physics. 
  417 
  

  

  chloride 
  or 
  acetate 
  of 
  rosanilin) 
  is 
  dissolved 
  in 
  1000 
  cc 
  of 
  water 
  

   and 
  to 
  the 
  solution, 
  with 
  shaking, 
  8 
  CC 
  of 
  saturated 
  bisulphite 
  and 
  

   about 
  10 
  cc 
  of 
  hydrochloric 
  acid 
  of 
  1*19 
  sp. 
  gr. 
  are 
  added. 
  To 
  

   apply 
  the 
  test 
  solid 
  salts 
  are 
  treated 
  with 
  a 
  25 
  per 
  cent 
  solution 
  

   of 
  chromic 
  acid, 
  but 
  carbonates 
  are 
  treated 
  with 
  hydrochloric 
  or 
  

   sulphuric 
  acid 
  and 
  then 
  chromic 
  acid 
  is 
  added 
  in 
  extremely 
  con- 
  

   centrated 
  solution, 
  so 
  that 
  the 
  dilution 
  may 
  not 
  be 
  too 
  great. 
  

   The 
  test 
  seems 
  to 
  be 
  applied 
  usually 
  by 
  hanging 
  the 
  test-paper 
  

   in 
  the 
  neck 
  of 
  a 
  flask 
  in 
  which 
  the 
  bromine 
  is 
  set 
  free. 
  Several 
  

   aniline 
  dyes 
  may 
  be 
  used 
  in 
  the 
  same 
  way 
  for 
  this 
  test, 
  including 
  

   Hofmann's 
  violet. 
  The 
  reaction 
  succeeds 
  even 
  in 
  the 
  presence 
  of 
  

   free 
  chlorine 
  and 
  iodine. 
  When 
  much 
  iodine 
  is 
  present 
  the 
  paper 
  

   is 
  colored 
  brown 
  so 
  that 
  the 
  blue 
  bromine 
  color 
  is 
  hidden, 
  but 
  

   the 
  latter 
  appears 
  when 
  the 
  paper 
  is 
  exposed 
  for 
  a 
  short 
  time 
  to 
  

   the 
  air. 
  By 
  these 
  reagents 
  the 
  author 
  has 
  detected 
  bromine 
  in 
  a 
  

   large 
  number 
  of 
  substances, 
  including 
  sodium 
  carbonate 
  and 
  

   bicarbonate, 
  wood-ashes, 
  urine, 
  samples 
  of 
  the 
  purest 
  chlorides 
  

   and 
  hydrochloric 
  acid.— 
  Zeitschr. 
  f. 
  analyt. 
  Ghem., 
  lii, 
  538. 
  

  

  H. 
  L. 
  W. 
  

  

  3. 
  Calcium 
  Hydride. 
  — 
  The 
  observation 
  by 
  Moissan 
  in 
  1899 
  

   that 
  metallic 
  calcium 
  absorbs 
  hydrogen 
  gas 
  at 
  and 
  above 
  a 
  dull 
  

   red 
  heat, 
  forming 
  a 
  white, 
  crystalline 
  compound 
  of 
  the 
  composi- 
  

   tion 
  CaH 
  2 
  , 
  has 
  led 
  to 
  the 
  manufacture 
  of 
  this 
  substance 
  on 
  the 
  

   large 
  scale 
  at 
  the 
  electro-chemical 
  works 
  at 
  Bitterfeld 
  for 
  the 
  pur- 
  

   pose 
  of 
  its 
  use 
  as 
  a 
  convenient 
  means 
  of 
  producing 
  hydrogen 
  gas 
  

   for 
  military 
  requirements 
  by 
  treating 
  it 
  with 
  water. 
  It 
  has 
  been 
  

   found 
  that 
  the 
  hydride 
  may 
  be 
  produced 
  in 
  large 
  solid 
  pieces 
  by 
  

   leading 
  hydrogen 
  gas 
  into 
  molten 
  metallic 
  calcium, 
  and 
  since 
  the 
  

   melting 
  point 
  of 
  calcium 
  is 
  at 
  about 
  800° 
  C. 
  it 
  appears 
  that 
  the 
  

   hydride 
  must 
  be 
  stable 
  at 
  a 
  rather 
  high 
  temperature. 
  Molden- 
  

   hader 
  and 
  Roll-Hansen, 
  in 
  attempting 
  to 
  determine 
  the 
  pres- 
  

   sure 
  of 
  dissociation 
  of 
  this 
  substance 
  by 
  heating 
  it 
  in 
  porcelain 
  

   tubes, 
  found 
  that 
  it 
  reacted 
  with 
  the 
  porcelain 
  and 
  gave 
  too 
  high 
  

   results, 
  but 
  by 
  protecting 
  the 
  porcelain 
  with 
  sheet 
  iron, 
  the 
  pres- 
  

   sure 
  at 
  780° 
  C. 
  was 
  found 
  to 
  be 
  ll 
  mm 
  of 
  mercury, 
  while 
  it 
  

   increased 
  in 
  a 
  regular 
  curve 
  until 
  at 
  1027° 
  it 
  was 
  *705 
  mm 
  . 
  The 
  

   results 
  of 
  these 
  experiments 
  indicated 
  also 
  the 
  existence 
  of 
  a 
  

   second 
  hydride, 
  Call, 
  more 
  stable 
  than 
  the 
  CaH 
  2 
  . 
  — 
  Zeitschr. 
  anor- 
  

   gan. 
  Chem., 
  lxxxiii, 
  130. 
  h. 
  l. 
  w. 
  

  

  4. 
  Analysis 
  of 
  Special 
  Steels. 
  — 
  Dr. 
  S. 
  Zinbeeg, 
  Chief 
  Chemist 
  

   of 
  the 
  Putilow 
  Works 
  at 
  St. 
  Petersburg, 
  has 
  described 
  his 
  

   method 
  for 
  the 
  gravimetric 
  determination 
  of 
  tungsten, 
  chromium, 
  

   silicon, 
  nickel, 
  molybdenum 
  and 
  vanadium 
  in 
  the 
  presence 
  of 
  each 
  

   other 
  in 
  steels. 
  The 
  whole 
  process 
  is 
  too 
  long 
  for 
  description 
  

   here, 
  but 
  the 
  method 
  for 
  the 
  determination 
  of 
  tungsten, 
  as 
  a 
  first 
  

   step 
  in 
  the 
  operation, 
  appears 
  to 
  be 
  novel 
  and 
  worthy 
  of 
  notice. 
  

   One 
  gram 
  of 
  the 
  sample 
  of 
  steel 
  is 
  treated 
  with 
  dilute 
  hydro- 
  

   chloric 
  acid 
  (1 
  : 
  4), 
  by 
  heating, 
  as 
  long 
  as 
  there 
  is 
  any 
  action. 
  

   The 
  metallic 
  tungsten 
  thus 
  left 
  as 
  a 
  residue 
  is 
  known 
  to 
  contain 
  

   more 
  or 
  less 
  chromium 
  carbide 
  and 
  iron. 
  The 
  liquid 
  is 
  then 
  

  

  