﻿Chemistry 
  and 
  Physics. 
  241 
  

  

  SCIENTIFIC 
  INTELLIGENCE. 
  

  

  I. 
  Chemistry 
  and 
  Physics. 
  

  

  1. 
  On 
  the 
  Density 
  of 
  Helium. 
  — 
  Ramsay 
  has 
  continued 
  his 
  

   researches 
  on 
  the 
  gaseous 
  constituents 
  of 
  minerals. 
  While 
  the 
  

   gas 
  from 
  cleveite 
  contains 
  some 
  nitrogen 
  and 
  no 
  hydrogen, 
  that 
  

   from 
  broggerite, 
  samarskite 
  and 
  fergusonite, 
  obtained 
  by 
  heating 
  

   the 
  mineral 
  in 
  a 
  vacuum, 
  is 
  rich 
  in 
  hydrogen 
  but 
  contains 
  only 
  an 
  

   infinitesimal 
  amount 
  of 
  nitrogen. 
  From 
  one 
  gram 
  of 
  cleveite 
  

   7*2 
  CC 
  of 
  helium 
  were 
  obtained 
  ; 
  while 
  from 
  one 
  gram 
  of 
  broggerite 
  

   less 
  than 
  l 
  cc 
  , 
  from 
  one 
  gram 
  of 
  samarskite 
  only 
  0*6 
  CC 
  and 
  from 
  

   fergusonite 
  (by 
  heating 
  alone) 
  only 
  1*1 
  cc 
  per 
  gram 
  were 
  obtained. 
  

   This 
  latter 
  gas 
  contained 
  hydrogen 
  54*7, 
  carbon 
  dioxide 
  13*9 
  and 
  

   helium 
  31*2 
  per 
  cent. 
  For 
  the 
  density 
  determinations 
  the 
  gas 
  was 
  

   purified 
  by 
  treating 
  it 
  with 
  caustic 
  soda 
  and 
  then 
  passing 
  it 
  over 
  

   red 
  hot 
  copper 
  oxide, 
  soda-lime 
  and 
  phosphoric 
  oxide. 
  The 
  

   helium 
  from 
  broggerite 
  and 
  cleveite 
  mixed 
  had 
  a 
  density 
  of 
  

   2*21 
  8 
  ; 
  and 
  after 
  a 
  second 
  treatment 
  one 
  of 
  2-133. 
  That 
  from 
  brog- 
  

   gerite 
  alone 
  gave 
  2*181. 
  That 
  from 
  samarskite, 
  obtained 
  by 
  heat 
  

   alone, 
  2-121; 
  obtained 
  by 
  fusion 
  with 
  HKS0 
  4 
  , 
  2*122; 
  falling 
  to 
  

   2*117 
  after 
  a 
  second 
  treatment, 
  and 
  to 
  2*114 
  after 
  a 
  third 
  one; 
  

   the 
  mean 
  being 
  2*118. 
  The 
  gas 
  from 
  fergusonite 
  obtained 
  by 
  

   heat 
  alone 
  gave 
  in 
  one 
  sample 
  2*147, 
  in 
  another 
  2*139 
  and 
  in 
  a 
  

   third 
  2*134 
  ; 
  the 
  mean 
  being 
  2*140. 
  It 
  may 
  be, 
  therefore, 
  that 
  

   helium 
  from 
  various 
  sources 
  is 
  not 
  quite 
  homogeneous, 
  different 
  

   samples 
  varying 
  in 
  density. 
  The 
  light 
  given 
  by 
  a 
  vacuum 
  tube 
  

   containing 
  cleveite 
  gas 
  has 
  a 
  richer 
  orange-yellow 
  shade 
  than 
  that 
  

   from 
  the 
  other 
  three 
  minerals. 
  Moreover 
  this 
  cleveite 
  gas 
  shows 
  

   a 
  special 
  set 
  of 
  fairly 
  strong 
  lines 
  between 
  the 
  green 
  and 
  the 
  blue 
  

   which 
  have 
  never 
  been 
  observed 
  in 
  the 
  gases 
  obtained 
  from 
  the 
  

   other 
  minerals. 
  — 
  Proc. 
  Roy. 
  Soc, 
  lix, 
  325, 
  1896. 
  g. 
  f. 
  b. 
  

  

  2. 
  On 
  the 
  expansion 
  of 
  Helium 
  and 
  Argon. 
  — 
  By 
  means 
  of 
  

   thermometers 
  containing 
  air, 
  hydrogen, 
  argon 
  and 
  helium 
  respec- 
  

   tively, 
  Kuenen 
  and 
  Raxdall 
  have 
  determined 
  the 
  relative 
  

   coefficients 
  of 
  expansion 
  of 
  these 
  gases, 
  at 
  the 
  temperatures 
  of 
  

   the 
  melting 
  point 
  of 
  ice, 
  and 
  the 
  boiling 
  points 
  of 
  water, 
  chlor- 
  

   benzene, 
  aniline, 
  quinolene, 
  and 
  bromnaphthalene. 
  The 
  helium 
  

   used 
  had 
  a 
  density 
  of 
  2*13, 
  and 
  the 
  argon, 
  which 
  was 
  prepared 
  

   from 
  air 
  by 
  means 
  of 
  magnesium, 
  a 
  density 
  of 
  19*99. 
  From 
  the 
  

   pressure 
  readings 
  at 
  0° 
  and 
  at 
  100°, 
  the 
  mean 
  coefficient 
  for 
  

   helium 
  between 
  these 
  limits 
  was 
  found 
  to 
  be 
  0*003665, 
  for 
  argon 
  

   0*003668, 
  and 
  for 
  air 
  0*003663. 
  Using 
  these 
  figures, 
  the 
  authors 
  

   calculated 
  the 
  boiling 
  points 
  of 
  the 
  other 
  substances 
  above 
  men- 
  

   tioned 
  and 
  found 
  them 
  to 
  accord 
  closely. 
  Though 
  no 
  very 
  high 
  

   precision 
  is 
  claimed 
  for 
  these 
  results, 
  they 
  serve 
  to 
  show 
  that 
  argon 
  

   and 
  helium 
  may 
  be 
  regarded 
  in 
  so 
  far 
  as 
  perfect 
  gases. 
  — 
  Proc. 
  

   Boy. 
  Soc, 
  lix, 
  198, 
  1896. 
  g. 
  r. 
  b. 
  

  

  3. 
  On 
  the 
  electric 
  discharge 
  in 
  Argon 
  and 
  Helium. 
  — 
  Experi- 
  

  

  