﻿314 
  Scientific 
  Intelligence. 
  

  

  drop 
  with 
  constant 
  shaking, 
  until 
  a 
  faint 
  permanent 
  yellow 
  color 
  

   appears. 
  On 
  neutralizing 
  with 
  sodium 
  carbonate, 
  a 
  heavy 
  white 
  

   crystalline 
  precipitate 
  is 
  produced, 
  which 
  after 
  washing 
  and 
  dry- 
  

   ing, 
  finally 
  in 
  vacuo 
  over 
  sulphuric 
  acid, 
  proved 
  to 
  be 
  sodium 
  

   dihydroxytartrate. 
  From 
  this 
  salt, 
  by 
  covering 
  it 
  with 
  anhy- 
  

   drous 
  ether 
  and 
  passing 
  dry 
  hydrogen 
  chloride 
  into 
  the 
  mixture, 
  

   dihydroxytartaric 
  was 
  obtained 
  on 
  evaporation. 
  Owing 
  to 
  the 
  

   ease 
  with 
  which 
  this 
  acid 
  can 
  now 
  be 
  procured, 
  the 
  author 
  sug- 
  

   gests 
  the 
  use 
  ol 
  it 
  as 
  a 
  reagent 
  for 
  the 
  detection 
  of 
  sodium. 
  For 
  

   this 
  purpose, 
  a 
  few 
  crystals 
  of 
  the 
  acid 
  are 
  dissolved 
  in 
  a 
  drop 
  of 
  

   water 
  on 
  a 
  watch-glass, 
  the 
  solution 
  to 
  be 
  examined 
  is 
  added 
  and 
  

   if 
  necessary 
  the 
  liquid 
  is 
  neutralized 
  with 
  a 
  drop 
  of 
  ammonia. 
  On 
  

   stirring 
  with 
  a 
  rod, 
  a 
  white 
  crystalline 
  precipitate 
  of 
  the 
  sodium 
  

   salt 
  appears, 
  generally 
  in 
  lines 
  as 
  in 
  the 
  detection 
  of 
  potassium 
  

   by 
  tartaric 
  acid. 
  The 
  test 
  is 
  fairly 
  delicate, 
  a 
  one 
  per 
  cent 
  solu- 
  

   tion 
  of 
  sodium 
  chloride 
  giving 
  the 
  reaction 
  almost 
  immediately. 
  

   Neither 
  potassium 
  nor 
  ammonium 
  interferes 
  with 
  the 
  reaction. 
  — 
  

   J. 
  Chem. 
  Soc, 
  lxvii, 
  48, 
  January, 
  1895. 
  g. 
  e. 
  b. 
  

  

  6. 
  On 
  the 
  Commercial 
  Synthesis 
  of 
  Acetylene. 
  — 
  The 
  produc- 
  

   tion 
  of 
  the 
  carbides 
  of 
  barium, 
  strontium 
  and 
  calcium, 
  by 
  Mois- 
  

   san 
  in 
  his 
  electric 
  furnace,* 
  seems 
  likely 
  to 
  become 
  of 
  considerable 
  

   commercial 
  utility. 
  In 
  a 
  paper 
  by 
  Lewes, 
  read 
  before 
  the 
  Society 
  

   of 
  Arts, 
  he 
  has 
  called 
  attention 
  to 
  the 
  production 
  of 
  acetylene 
  by 
  

   the 
  action 
  of 
  water 
  upon 
  these 
  carbides 
  as 
  the 
  starting 
  point 
  of 
  

   important 
  practical 
  developments. 
  Although 
  Wobler 
  had 
  made 
  

   calcium 
  carbide 
  by 
  fusing 
  an 
  alloy 
  of 
  zinc 
  and 
  calcium 
  with 
  car- 
  

   bon, 
  and 
  had 
  obtained 
  acetylene 
  from 
  it 
  by 
  the 
  action 
  of 
  water 
  ; 
  

   and 
  although 
  in 
  1892 
  Macquenne 
  had 
  made 
  barium 
  carbide 
  by 
  

   heating 
  together 
  barium 
  carbonate, 
  magnesium 
  powder 
  and 
  char- 
  

   coal, 
  and 
  still 
  later 
  Travers 
  had 
  made 
  calcium 
  carbide 
  by 
  the 
  

   action 
  of 
  a 
  high 
  temperature 
  upon 
  a 
  mixture 
  of 
  calcium 
  chloride, 
  

   carbon 
  and 
  sodium, 
  yet 
  no 
  commercial 
  importance 
  was 
  attached 
  

   to 
  these 
  processes 
  on 
  account 
  of 
  their 
  expense. 
  But 
  when 
  work- 
  

   ing 
  with 
  the 
  electric 
  furnace, 
  in 
  the 
  attempt 
  to 
  form 
  alloys 
  of 
  cal- 
  

   cium, 
  Willson 
  observed 
  that 
  a 
  mixture 
  of 
  lime 
  and 
  pulverized 
  

   anthracite, 
  exposed 
  to 
  the 
  high 
  temperature 
  of 
  the 
  arc, 
  fused 
  to 
  a 
  

   semi-metallic 
  mass, 
  which 
  when 
  thrown 
  into 
  water, 
  effervesced 
  

   strongly 
  and 
  evolved 
  acetylene, 
  the 
  process 
  became 
  of 
  practical 
  

   value. 
  The 
  calcium 
  carbide 
  thus 
  produced 
  is 
  a 
  dark 
  gray 
  sub- 
  

   stance, 
  having 
  a 
  density 
  of 
  2-262. 
  When 
  pure 
  a 
  pound 
  of 
  it 
  

   yields 
  5-5 
  cubic 
  feet 
  of 
  gas, 
  containing 
  98 
  per 
  cent 
  of 
  acetylene. 
  

   This 
  gas 
  is 
  colorless, 
  with 
  a 
  penetrating 
  odor 
  resembling 
  garlic. 
  

   It 
  is 
  poisonous, 
  and 
  is 
  soluble 
  in 
  a 
  little 
  less 
  than 
  its 
  own 
  volume 
  

   of 
  water, 
  and 
  in 
  one-sixth 
  of 
  its 
  volume 
  of 
  alcohol. 
  It 
  has 
  a 
  

   density 
  of 
  0*91. 
  It 
  burns 
  with 
  a 
  highly 
  luminous 
  and 
  smoky 
  

   flame, 
  and 
  liquefies 
  at 
  0° 
  C. 
  under 
  a 
  pressure 
  of 
  21*5 
  atmospheres. 
  

   When 
  sprayed 
  into 
  the 
  air 
  the 
  liquid 
  evaporates 
  rapidly, 
  absorb- 
  

   ing 
  so 
  much 
  heat 
  that 
  a 
  portion 
  of 
  it 
  is 
  converted 
  into 
  a 
  snow- 
  

   white 
  solid. 
  For 
  illuminating 
  purposes 
  it 
  can 
  be 
  burned 
  only 
  in 
  

  

  *See 
  this 
  Journal, 
  III, 
  xlviii, 
  506, 
  December, 
  1894. 
  

  

  