﻿Chemistry 
  and 
  Physics. 
  73 
  

  

  of 
  iron 
  and 
  silicium 
  in 
  the 
  electric 
  furnace. 
  It 
  is 
  in 
  the 
  form 
  of 
  

   tetrahedral 
  crystals 
  having 
  a 
  density 
  of 
  6*17 
  at 
  15°. 
  They 
  

   scratch 
  quartz 
  but 
  not 
  corundum. 
  Iron 
  silicide 
  is 
  not 
  attacked 
  

   by 
  oxygen 
  or 
  hydrogen 
  at 
  a 
  red 
  heat, 
  but 
  chlorine, 
  bromine 
  and 
  

   fluorine 
  act 
  upon 
  it 
  at 
  a 
  red 
  heat 
  with 
  incandescence. 
  Mineral 
  

   acids 
  are 
  without 
  action 
  upon 
  it, 
  but 
  fused 
  alkalis, 
  or 
  a 
  mixture 
  of 
  

   fused 
  nitrate 
  and 
  carbonate, 
  attack 
  it 
  readily. 
  — 
  G. 
  H., 
  cxxviii, 
  

   933-936, 
  April, 
  1899. 
  G. 
  r. 
  b. 
  

  

  3. 
  On 
  cm 
  A2)2:)Ucation 
  of 
  the 
  Equilibrium 
  Law 
  to 
  the 
  Forma- 
  

   tion 
  of 
  Oceanic 
  Salt 
  Deposits. 
  — 
  An 
  investigation 
  has 
  been 
  

   undertaken 
  by 
  Van't 
  Hoff 
  and 
  Meyekhoffer 
  for 
  the 
  purpose 
  

   of 
  determining 
  theoretically 
  from 
  the 
  law 
  of 
  equilibrium 
  the 
  

   order 
  of 
  deposition 
  of 
  salts 
  in 
  consequence 
  of 
  the 
  evaporation 
  of 
  

   sea 
  water, 
  with 
  especial 
  reference 
  to 
  the 
  Stassfurt 
  beds. 
  Evi- 
  

   dently, 
  the 
  relations 
  of 
  the 
  individual 
  salts 
  present 
  to 
  each 
  other 
  

   have 
  to 
  be 
  first 
  considered, 
  and 
  the 
  present 
  paper 
  considers 
  the 
  

   solubility 
  curves 
  of 
  the 
  various 
  hydrates 
  of 
  magnesium 
  chloride 
  

   at 
  temperatures 
  varying 
  from 
  — 
  33'6° 
  to 
  +186°, 
  the 
  point 
  when 
  

   hydrogen 
  chloride 
  begins 
  to 
  be 
  evolved. 
  The 
  complete 
  equi- 
  

   librium 
  curve 
  for 
  magnesium 
  chloride 
  and 
  water 
  may 
  be 
  divided 
  

   into 
  the 
  following 
  portions 
  : 
  (1) 
  Stable 
  solution 
  in 
  equilibrium 
  

   with 
  ice, 
  from 
  0° 
  to 
  —33*6° 
  ; 
  (2) 
  Stable 
  solutions 
  in 
  equilibrium 
  

   with 
  the 
  followinor 
  hydrates, 
  MgCl, 
  . 
  (H^O),, 
  from 
  —33-6° 
  to 
  

   -16-8°; 
  MgCI..(H.0)3 
  from 
  -1^3.8" 
  to 
  -3-4°; 
  MgClJH^), 
  

   from 
  —3-4° 
  to" 
  116'67°; 
  MgCl, 
  . 
  (H^O)^ 
  from 
  116-67 
  to 
  181°; 
  

   MgCi, 
  . 
  (H,0). 
  above 
  181° 
  or 
  182°; 
  (3) 
  labile 
  solution 
  in 
  equi- 
  

   librium 
  with 
  MgCl,.(Hp)X/3) 
  from 
  —17-4° 
  to 
  —9-6°. 
  Labile 
  

   continuations 
  of 
  the 
  curves 
  for 
  the 
  hexahydrate 
  and 
  the 
  dode- 
  

   cahydrate 
  can 
  be 
  obtained, 
  meeting 
  at 
  —30°, 
  whilst 
  similar 
  con- 
  

   tinuations 
  of 
  the 
  ice 
  and 
  octahydrate 
  equilibrium 
  curves 
  cut 
  at 
  

   — 
  50°. 
  The 
  dodecahydrate 
  was 
  previously 
  unknown 
  and 
  is 
  best 
  

   produced 
  by 
  cooling 
  a 
  solution 
  containing 
  a 
  little 
  more 
  water 
  

   than 
  is 
  required 
  for 
  the 
  crystals, 
  to 
  about 
  —20° 
  and 
  then 
  induc- 
  

   ing 
  local 
  over-cooling 
  by 
  solid 
  carbon 
  dioxide. 
  The 
  stable 
  and 
  

   labile 
  octahydrates 
  also 
  previously 
  unknown 
  can 
  be 
  produced 
  in 
  

   a 
  similar 
  manner 
  by 
  cooling 
  a 
  solution 
  of 
  the 
  composition 
  MgCI^ 
  . 
  

   (H^O)^^. 
  Once 
  formed, 
  the 
  labile 
  hydrate 
  might 
  remain 
  unchanged 
  

   for 
  a 
  whole 
  day, 
  but 
  its 
  production 
  could 
  not 
  be 
  depended 
  on. 
  

   The 
  values 
  found 
  for 
  the 
  solubility 
  of 
  the 
  hexahydrate 
  were 
  in 
  

   general 
  slightly 
  lower 
  than 
  those 
  of 
  other 
  observers, 
  probably 
  

   owing 
  to 
  more 
  complete 
  freedom 
  from 
  calcium 
  chloride. 
  — 
  Zeitschr. 
  

   physikal. 
  Chem., 
  xxvii, 
  75-93 
  ; 
  J. 
  Chem. 
  Soc, 
  Ixxiv, 
  564, 
  Decem- 
  

   ber, 
  1898. 
  G. 
  F. 
  B. 
  

  

  4. 
  The 
  Spirit 
  of 
  Organic 
  Chemistry^ 
  an 
  Introduction 
  to 
  the 
  

   Current 
  Literature 
  of 
  the 
  Subject 
  ; 
  by 
  Arthuk 
  Lachman. 
  12mo, 
  

   pp. 
  xviii 
  + 
  229. 
  New 
  York 
  (The 
  Macmillan 
  Company). 
  — 
  This 
  

   book, 
  which 
  is 
  intended 
  primarily 
  as 
  a 
  supplement 
  to 
  text-books 
  

   of 
  organic 
  chemistry, 
  consists 
  of 
  nine 
  excellent 
  essays 
  upon 
  the 
  

   development 
  of 
  some 
  of 
  the 
  most 
  important 
  problems 
  of 
  the 
  

   science. 
  The 
  subjects 
  dealt 
  with 
  are, 
  the 
  constitution 
  of 
  rosani- 
  

  

  