﻿58 
  Scientific 
  Intelligence. 
  

  

  index. 
  The 
  uncorrected 
  results 
  vary 
  between 
  31 
  '60° 
  and 
  31-62° 
  

   only, 
  and 
  the 
  corrected 
  value 
  lor 
  the 
  critical 
  point 
  is 
  given 
  as 
  

   31-40°; 
  in 
  close 
  agreement 
  with 
  Amagat's 
  value 
  31 
  -35°. 
  — 
  C. 
  JR., 
  

   cxviii, 
  976, 
  April, 
  1894. 
  g. 
  f. 
  b. 
  

  

  5. 
  On 
  the 
  Constants 
  of 
  Refraction 
  of 
  Carbonyl 
  Compounds. 
  

   — 
  In 
  order 
  to 
  ascertain 
  the 
  influence 
  exerted 
  by 
  the 
  presence 
  of 
  a 
  

   number 
  of 
  carbonyl 
  groups 
  in 
  a 
  molecule 
  upon 
  its 
  molecular 
  re- 
  

   fraction, 
  Nasini 
  and 
  Anderltni 
  have 
  determined 
  the 
  constants 
  

   of 
  refraction 
  of 
  several 
  carbonyl 
  compounds. 
  Mond 
  and 
  Nasini 
  

   had 
  attributed 
  the 
  exceptionally 
  high 
  molecular 
  refraction 
  of 
  

   nickel 
  tetracarbonyl 
  to 
  the 
  fact 
  that 
  in 
  this 
  substance 
  nickel 
  is 
  an 
  

   octad. 
  But 
  Gladstone 
  had 
  expressed 
  the 
  opinion 
  that 
  the 
  equally 
  

   high 
  molecular 
  refraction 
  of 
  ferropentacarbonyl, 
  is 
  due 
  rather 
  to 
  

   the 
  peculiar 
  arrangement 
  of 
  the 
  carbonyl 
  groups 
  than 
  to 
  the 
  pres- 
  

   ence 
  of 
  iron 
  as 
  a 
  decad. 
  The 
  substances 
  examined 
  were 
  qui- 
  

   none, 
  diacetyl, 
  dipropionyl, 
  tetrachlorotetraketohexamethylene, 
  

   dibromodichlorotetraketohexamethylene, 
  leuconic 
  acid 
  and 
  potas- 
  

   sium 
  croconate 
  ; 
  the 
  last 
  two 
  being 
  examined 
  in 
  solution 
  in 
  water, 
  

   and 
  the 
  others 
  (excepting 
  the 
  second 
  and 
  third) 
  in 
  solution 
  in 
  

   benzene. 
  The 
  measurements 
  were 
  made 
  for 
  the 
  line 
  H« 
  and 
  the 
  

   results 
  calculated 
  both 
  for 
  the 
  formula 
  M(yu— 
  l) 
  / 
  d 
  and 
  the 
  formula 
  

   M(// 
  — 
  1)/ 
  (yu 
  2 
  — 
  2)o\ 
  It 
  was 
  observed 
  that 
  the 
  experimental 
  val- 
  

   ues 
  agreed 
  well 
  with 
  the 
  calculated 
  ones. 
  If, 
  however, 
  the 
  atomic 
  

   refraction 
  of 
  potassium 
  be 
  taken 
  as 
  8'1 
  as 
  given 
  by 
  Gladstone, 
  

   the 
  observed 
  molecular 
  refraction 
  of 
  potassium 
  croconate 
  be- 
  

   comes 
  58'20 
  for 
  the 
  first 
  formula 
  given 
  above; 
  so 
  that 
  if 
  the 
  ordi- 
  

   nary 
  constant 
  be 
  assigned 
  to 
  the 
  carbonyl 
  groups, 
  the 
  atomic 
  

   refraction 
  of 
  potassium 
  must 
  be 
  taken 
  as 
  22*5 
  for 
  the 
  first, 
  and 
  

   12-40 
  for 
  the 
  second, 
  of 
  these 
  formulas. 
  Since 
  the 
  measurements 
  

   made 
  on 
  the 
  other 
  carbonyl 
  compounds 
  show 
  that 
  the 
  presence 
  

   of 
  several 
  carbonyl 
  groups 
  causes 
  no 
  abnormal 
  increase 
  in 
  the 
  

   molecular 
  refraction, 
  the 
  authors 
  attribute 
  the 
  abnormally 
  high 
  

   molecular 
  refraction 
  of 
  this 
  substance 
  to 
  the 
  metal 
  alone 
  ; 
  though 
  

   they 
  admit 
  that 
  the 
  anomalous 
  results 
  sometimes 
  obtained 
  with 
  

   such 
  compounds 
  may 
  be 
  due 
  in 
  part 
  to 
  the 
  fact 
  that 
  they 
  were 
  

   made 
  in 
  solution.— 
  Gazzetta 
  Chim. 
  Ital, 
  xxiv, 
  i, 
  157; 
  X 
  Chem. 
  

   Soc, 
  lxvi, 
  ii, 
  301, 
  August, 
  1894. 
  G. 
  f. 
  b. 
  

  

  6. 
  On 
  the 
  Electrolysis 
  of 
  Copper 
  Sulphate 
  in 
  Vacuo. 
  — 
  It 
  is 
  a 
  

   well 
  recognized 
  fact 
  that 
  the 
  electrolytic 
  deposition 
  of 
  copper 
  

   from 
  a 
  solution 
  of 
  its 
  sulphate 
  does 
  not 
  conform 
  rigorously 
  to 
  

   Faraday's 
  law 
  ; 
  Gray 
  having 
  shown 
  that 
  the 
  deposit 
  of 
  metal 
  is 
  

   heavier 
  the 
  higher 
  the 
  current 
  density 
  and 
  the 
  lower 
  the 
  temper- 
  

   ature. 
  This 
  appears 
  to 
  be 
  due 
  to 
  the 
  fact 
  that 
  copper 
  is 
  slightly 
  

   soluble 
  in 
  a 
  copper 
  sulphate 
  solution. 
  Since 
  Schuster 
  had 
  sug- 
  

   gested 
  that 
  this 
  solution 
  of 
  the 
  copper 
  is 
  due 
  to 
  the 
  oxygen 
  

   present 
  in 
  the 
  copper 
  sulphate 
  solution, 
  Gannox 
  has 
  made 
  a 
  com- 
  

   parison 
  between 
  the 
  masses 
  of 
  copper 
  deposited 
  in 
  two 
  voltame- 
  

   ters 
  in 
  series, 
  from 
  one 
  of 
  which 
  the 
  air 
  was 
  exhausted. 
  His 
  

   results 
  show 
  that 
  with 
  a 
  neutral 
  solution, 
  the 
  deposit 
  of 
  copper 
  in 
  

   the 
  vacuum 
  tube 
  is 
  higher 
  than 
  that 
  in 
  the 
  one 
  under 
  the 
  atmos- 
  

  

  