﻿80 
  Scientific 
  Intelligence. 
  

  

  2. 
  A 
  New 
  Reagent 
  for 
  Free 
  Chlorine. 
  — 
  The 
  detection 
  and 
  

   determination 
  of 
  active 
  chlorine 
  in 
  public 
  water 
  supplies 
  has 
  

   become 
  important 
  on 
  account 
  of 
  the 
  frequent 
  use 
  of 
  hypochlor- 
  

   ites 
  in 
  purifying 
  such 
  waters. 
  The 
  classical 
  reagent 
  potassium 
  

   iodide 
  with 
  starch 
  paste 
  is 
  generally 
  used 
  for 
  this 
  examination, 
  

   but 
  G. 
  A. 
  LeRoy 
  proposes 
  the 
  employment 
  of 
  the 
  chlorhydrate 
  

   of 
  hexamethyl-triparaminotriphenylmethane 
  for 
  the 
  purpose. 
  

   When 
  this 
  reagent 
  is 
  added 
  to 
  the 
  extent 
  of 
  a 
  few 
  thousandths 
  

   to 
  a 
  potable 
  water 
  containing 
  traces 
  of 
  free 
  chlorine, 
  a 
  violet 
  

   coloration 
  is 
  formed 
  immediately 
  and 
  this 
  varies 
  in 
  proportion 
  to 
  

   the 
  amount 
  present. 
  The 
  reagent 
  will 
  show 
  about 
  3 
  hundred- 
  

   millionths 
  of 
  chlorine, 
  while 
  potassium 
  iodide 
  and 
  starch 
  show 
  

   only 
  about 
  one 
  ten-millionth. 
  — 
  Comptes 
  Re?idus 
  i 
  clxv, 
  226. 
  

  

  H. 
  L. 
  W. 
  

  

  3. 
  The 
  Right 
  Honourable 
  Sir 
  Henry 
  Enfield 
  Roscoe, 
  A 
  Bio- 
  

   graphical 
  Sketch, 
  by 
  Sir 
  Edward 
  Thorpe. 
  8vo, 
  pp. 
  208. 
  Lon- 
  

   don, 
  1916 
  (Longmans, 
  Green 
  & 
  Co. 
  Price 
  $2.50 
  net). 
  — 
  The 
  

   distinguished 
  author 
  of 
  this 
  biography, 
  who 
  calls 
  himself 
  " 
  a 
  

   grateful 
  pupil, 
  an 
  attached 
  co-worker, 
  and 
  a 
  lifelong 
  friend 
  " 
  of 
  

   the 
  eminent 
  subject 
  of 
  his 
  essay, 
  has 
  produced 
  a 
  book 
  of 
  unusual 
  

   interest. 
  Roscoe's 
  name 
  is 
  well 
  known 
  to 
  chemists 
  on 
  account 
  of 
  

   his 
  text-books, 
  and 
  his 
  chemical 
  researches, 
  particularly 
  his 
  inves- 
  

   tigations 
  dealing 
  with 
  the 
  compounds 
  of 
  vanadium, 
  and 
  his 
  

   explanation 
  of 
  constant-boiling 
  acid 
  solutions. 
  But 
  this 
  story 
  of 
  

   his 
  life 
  shows 
  that 
  his 
  activities 
  were 
  important 
  in 
  many 
  direc- 
  

   tions. 
  He 
  did 
  effective 
  service 
  in 
  the 
  development 
  of 
  Owens 
  

   College, 
  Manchester, 
  he 
  was 
  active 
  in 
  scientific 
  societies 
  and 
  in 
  

   public 
  service, 
  and 
  gave 
  much 
  time 
  to 
  the 
  advancement 
  of 
  pop- 
  

   ular 
  and 
  technical 
  education. 
  After 
  teaching 
  for 
  nearly 
  30 
  years 
  

   at 
  Owens 
  College 
  he 
  was 
  elected 
  a 
  Member 
  of 
  Parliament 
  in 
  

   1885 
  and 
  held 
  his 
  seat 
  for 
  10 
  years. 
  He 
  died 
  in 
  1915 
  at 
  the 
  age 
  

   of 
  83 
  years. 
  His 
  biographer 
  characterizes 
  him 
  as 
  a 
  strenuous 
  high- 
  

   minded 
  man, 
  of 
  large 
  aims 
  and 
  generous 
  impulses, 
  who 
  spent 
  his 
  

   abilities 
  and 
  energies 
  unstintingly 
  in 
  promoting 
  the 
  welfare 
  of 
  

   science 
  and 
  the 
  good 
  of 
  his 
  kind. 
  The 
  book 
  coutains 
  a 
  fine 
  por- 
  

   trait 
  of 
  Roscoe 
  as 
  an 
  elderly 
  man. 
  h. 
  l. 
  w. 
  

  

  4. 
  A 
  Text-book 
  of 
  Inorganic 
  Chemistry 
  ; 
  by 
  A. 
  F. 
  Hollema^t, 
  

   Issued 
  in 
  English 
  in 
  Cooperation 
  with 
  H. 
  C. 
  Cooper. 
  8vo, 
  pp. 
  

   521. 
  New 
  York, 
  1916. 
  (John 
  Wiley 
  & 
  Sons, 
  Inc.) 
  — 
  This 
  is 
  the 
  

   fifth 
  edition 
  in 
  English, 
  the 
  first 
  of 
  which 
  appeared 
  15 
  years 
  ago, 
  

   of 
  an 
  excellent 
  and 
  widely-used 
  text-book. 
  The 
  present 
  issue 
  has 
  

   been 
  thoroughly 
  revised 
  and 
  many 
  parts 
  have 
  been 
  rewritten 
  by 
  

   the 
  American 
  collaborator, 
  so 
  that 
  the 
  recent 
  achievements 
  in 
  

   chemical 
  science 
  receive 
  consideration. 
  For 
  instance, 
  the 
  results 
  

   of 
  T. 
  W. 
  Richards 
  on 
  the 
  atomic 
  weight 
  of 
  radioactive 
  lead 
  iso- 
  

   topes 
  are 
  mentioned. 
  There 
  is 
  no 
  doubt 
  that 
  the 
  book 
  presents 
  

   the 
  whole 
  subject 
  in 
  a 
  very 
  satisfactory 
  way. 
  However, 
  it 
  is 
  

   decidedly 
  advanced 
  in 
  its 
  treatment 
  of 
  physico-chemical 
  topics 
  

   from 
  a 
  mathematical 
  standpoint, 
  but 
  it 
  is 
  stated 
  that 
  notwith- 
  

   standing 
  the 
  appearance 
  of 
  differential 
  formulae 
  in 
  the 
  book, 
  it 
  is 
  

  

  