﻿Chemistry 
  and 
  Physics. 
  411 
  

  

  by 
  the 
  plants. 
  Acting 
  upon 
  this 
  suggestion, 
  a 
  practical 
  method 
  

   of 
  controlling 
  the 
  trouble 
  was 
  found. 
  Fields 
  of 
  yellow, 
  unhealthy 
  

   plants 
  when 
  sprayed 
  with 
  solutions 
  of 
  iron 
  salts 
  became 
  green 
  in 
  

   a 
  very 
  short 
  time. 
  The 
  effect 
  on 
  the 
  fruit 
  was 
  most 
  remarkable. 
  

   The 
  small, 
  red, 
  stunted 
  pineapples, 
  when 
  sprayed, 
  showed 
  decided 
  

   improvement 
  within 
  a 
  week, 
  becoming 
  normally 
  dark 
  green, 
  and 
  

   commencing 
  a 
  vigorous 
  growth 
  within 
  two 
  or 
  three 
  weeks. 
  

   When 
  iron 
  was 
  applied 
  to 
  one 
  side 
  only 
  of 
  the 
  unripe 
  fruit, 
  that 
  

   side 
  became 
  green 
  first 
  and 
  made 
  such 
  growth 
  as 
  to 
  distort 
  the 
  

   shape 
  of 
  the 
  fruit, 
  but 
  later 
  the 
  iron 
  appeared 
  to 
  be 
  distributed 
  

   and 
  the 
  fruit 
  became 
  fairly 
  symmetrical 
  when 
  ripe. 
  Practically 
  

   all 
  the 
  pineapple 
  plantations 
  have 
  now 
  applied 
  spraying 
  with 
  fer- 
  

   rous 
  sulphate 
  solution 
  on 
  the 
  manganiferous 
  soils 
  with 
  apparently 
  

   perfect 
  success 
  in 
  profitable 
  cultivation. 
  — 
  Jour. 
  Indust. 
  and 
  Eng. 
  

   Chem., 
  ix, 
  47. 
  h. 
  l. 
  w. 
  

  

  3. 
  Preparation 
  of 
  Sulphurous 
  Acid. 
  — 
  It 
  is 
  stated 
  by 
  Edward 
  

   Hart 
  that 
  the 
  cheapest 
  and 
  most 
  convenient 
  method 
  for 
  prepar- 
  

   ing 
  small 
  amounts 
  of 
  sulphur 
  dioxide 
  in 
  the 
  laboratory 
  consists 
  in 
  

   warming 
  fuming 
  sulphuric 
  acid 
  containing 
  30 
  per 
  cent 
  of 
  S0 
  3 
  

   with 
  sulphur 
  in 
  the 
  form 
  of 
  lumps. 
  The 
  sulphur 
  dissolves 
  form- 
  

   ing 
  a 
  blue 
  solution 
  from 
  which, 
  on 
  warming, 
  S0 
  2 
  is 
  given 
  off 
  

   mixed 
  with 
  some 
  S0 
  3 
  . 
  If 
  sulphuric 
  acid 
  is 
  objectionable 
  the 
  

   resulting 
  solution 
  may 
  be 
  warmed 
  and 
  the 
  gas 
  again 
  absorbed. 
  

   The 
  evolution 
  of 
  SO 
  a 
  ceases 
  when 
  the 
  SO 
  s 
  has 
  been 
  acted 
  upon 
  and 
  

   the 
  sulphur 
  melts. 
  The 
  sulphuric 
  acid 
  remaining 
  contains 
  only 
  a 
  

   small 
  amount 
  of 
  dissolved 
  sulphur 
  and 
  is 
  fit 
  for 
  most 
  uses. 
  — 
  Jour. 
  

   Amer. 
  Chem. 
  jSoc, 
  xxxix, 
  376. 
  h. 
  l. 
  av. 
  

  

  4. 
  Gas 
  Chemists'' 
  Handbook, 
  Compiled 
  by 
  Technical 
  Commit- 
  

   tee, 
  Sub-Committee 
  on 
  Chemical 
  Tests, 
  The 
  American 
  Gas 
  In- 
  

   stitute. 
  8vo, 
  pp. 
  354. 
  New 
  York, 
  1916 
  (The 
  American 
  Gas 
  

   Institute, 
  New 
  York 
  City). 
  — 
  This 
  compilation 
  has 
  been 
  made 
  by 
  

   a 
  committee 
  of 
  eleven 
  prominent 
  gas 
  works 
  chemists, 
  of 
  whom 
  

   C. 
  C. 
  Tutwiler 
  is 
  chairman, 
  under 
  the 
  editorship 
  of 
  A. 
  F. 
  Kun- 
  

   berger. 
  It 
  is 
  a 
  very 
  useful 
  book, 
  not 
  only 
  for 
  chemists 
  connected 
  

   with 
  the 
  gas 
  industry 
  for 
  whose 
  use 
  it 
  is 
  particularly 
  intended, 
  

   but 
  also 
  for 
  other 
  analysts 
  who 
  may 
  desire 
  information 
  in 
  regard 
  

   to 
  the 
  special 
  methods 
  used 
  by 
  these 
  chemists. 
  The 
  book 
  has 
  a 
  

   wider 
  scope 
  than 
  would 
  perhaps 
  be 
  expected, 
  as 
  it 
  deals 
  not 
  only 
  

   with 
  the 
  examination 
  of 
  the 
  raw 
  materials 
  and 
  the 
  products 
  of 
  

   gas 
  manufacture, 
  but 
  also 
  with 
  the 
  tests 
  of 
  many 
  miscellaneous 
  

   materials, 
  such 
  as 
  boiler-waters, 
  paints, 
  fire-clays, 
  lubricating 
  oils, 
  

   solders, 
  and 
  other 
  alloys, 
  lime, 
  cement, 
  and 
  both 
  ordinary 
  and 
  

   special 
  steels. 
  The 
  very 
  important 
  subject 
  of 
  sampling 
  is 
  well 
  

   presented 
  in 
  connection 
  with 
  the 
  various 
  materials 
  to 
  be 
  examined, 
  

   and 
  the 
  book 
  as 
  a 
  whole 
  may 
  be 
  regarded 
  as 
  an 
  excellent 
  treatise, 
  

   giving 
  very 
  full 
  and 
  clear 
  directions 
  of 
  well-selected 
  methods 
  of 
  

   examination 
  and 
  analysis. 
  • 
  h. 
  l. 
  w. 
  

  

  5. 
  Union 
  of 
  Glass 
  in 
  Optical 
  Contact 
  by 
  Heat 
  Treatment.— 
  

   In 
  many 
  optical 
  and 
  spectroscopic 
  investigations 
  much 
  annoyance 
  

   and 
  incomplete 
  success 
  arise 
  from 
  the 
  fact 
  that 
  it 
  seems 
  to 
  be 
  

  

  