﻿Chemistry 
  and 
  Physics. 
  377 
  

  

  pure 
  organic 
  chemistry 
  as 
  are 
  considered 
  essential 
  for 
  agricul- 
  

   tural 
  students, 
  and 
  is 
  entirely 
  qualitative, 
  while 
  a 
  second 
  part 
  

   deals 
  with 
  quantitative 
  estimations 
  and 
  technical 
  analyses 
  of 
  

   food 
  stuffs. 
  

  

  This 
  first 
  part 
  presents 
  a 
  course 
  of 
  22 
  laboratory 
  exercises, 
  

   giving 
  explicit 
  directions 
  for 
  the 
  experiments, 
  with 
  explanatory 
  

   notes 
  in 
  each 
  case. 
  The 
  experiments 
  are 
  generally 
  very 
  simple 
  

   in 
  character, 
  but 
  they 
  should 
  give 
  the 
  student 
  considerable 
  

   familiarity 
  with 
  the 
  more 
  important 
  classes 
  of 
  organic 
  com- 
  

   pounds 
  that 
  are 
  important 
  in 
  connection 
  with 
  agriculture. 
  

  

  h. 
  l. 
  w. 
  

  

  4. 
  The 
  Magnetic 
  Susceptibilities 
  of 
  Certain 
  Gases. 
  — 
  Accurate 
  

   •experimental 
  determinations 
  of 
  the 
  magnetic 
  susceptibilities 
  of 
  

   gases 
  are 
  very 
  important 
  for 
  at 
  least 
  two 
  reasons, 
  (a) 
  the 
  num- 
  

   ber 
  of 
  gases 
  heretofore 
  investigated 
  is 
  small 
  and 
  the 
  data 
  ob- 
  

   tained 
  by 
  different 
  observers 
  for 
  the 
  same 
  gas 
  are, 
  in 
  some 
  cases, 
  

   highly 
  discordant, 
  and 
  (b) 
  various 
  theories 
  of 
  magnetization 
  

   have 
  been 
  advanced 
  from 
  time 
  to 
  time 
  which 
  do 
  not 
  agree 
  in 
  all 
  

   of 
  their 
  consequences 
  and 
  which 
  can 
  be 
  tested 
  and 
  differentiated 
  

   only 
  after 
  reliable 
  data 
  have 
  been 
  obtained. 
  

  

  The 
  latest 
  theory 
  of 
  magnetization 
  of 
  gases 
  was 
  developed 
  by 
  

   K. 
  Honda 
  and 
  J. 
  Okubo. 
  According 
  to 
  the 
  kinetic 
  theory 
  the 
  

   molecules 
  are 
  assumed 
  to 
  rotate 
  around 
  their 
  centers 
  of 
  mass 
  as 
  

   well 
  as 
  to 
  experience 
  translation 
  between 
  impacts. 
  In 
  the 
  mag- 
  

   netic 
  theory 
  in 
  question 
  the 
  molecules 
  are 
  treated 
  as 
  gyroscopes 
  

   whose 
  axes 
  of 
  rotation 
  do 
  not 
  coincide, 
  in 
  general, 
  with 
  the 
  mag- 
  

   netic 
  axes. 
  Accordingly 
  the 
  magnetic 
  moment 
  of 
  a 
  molecule 
  is 
  

   supposed 
  to 
  be 
  resolved 
  into 
  two 
  components 
  one 
  of 
  which 
  coin- 
  

   cides 
  with 
  the 
  axis 
  of 
  rotation 
  and 
  the 
  other, 
  perpendicular 
  to 
  

   this 
  axis. 
  Under 
  the 
  influence 
  of 
  a 
  magnetic 
  field 
  the 
  paramag- 
  

   netic 
  polarization 
  arises 
  from 
  the 
  parallel 
  component 
  and 
  the 
  

   diamagnetic 
  polarization 
  from 
  the 
  perpendicular 
  component, 
  the 
  

   resultant 
  polarization 
  being 
  the 
  sum 
  of 
  the 
  two. 
  The 
  resultant 
  

   may 
  be 
  positive 
  or 
  negative 
  according 
  as 
  the 
  paramagnetic 
  

   polarization 
  is 
  greater 
  than, 
  or 
  less 
  than, 
  the 
  diamagnetic 
  polari- 
  

   zation. 
  This 
  theory 
  shows' 
  that 
  the 
  sign 
  of 
  the 
  magnetization 
  

   of 
  a 
  gas 
  depends 
  upon 
  the 
  shape 
  of 
  the 
  molecules 
  but 
  not 
  upon 
  

   their 
  magnetic 
  moment. 
  

  

  In 
  order 
  to 
  test 
  this 
  theory 
  and 
  other 
  theories, 
  and 
  to 
  obtain 
  

   reliable 
  numerical 
  data, 
  the 
  magnetic 
  susceptibilities 
  of 
  certain 
  

   gases 
  have 
  been 
  recently 
  investigated 
  by 
  Take 
  Sone. 
  For 
  de- 
  

   tails 
  of 
  the 
  fairly 
  complicated 
  apparatus 
  employed 
  the 
  reader 
  

   must 
  be 
  referred 
  to 
  the 
  original 
  article. 
  However, 
  emphasis 
  

   should 
  be 
  laid 
  on 
  the 
  facts 
  that 
  the 
  investigator 
  took 
  elaborate 
  

   precautions 
  to 
  obtain 
  the 
  gases 
  in 
  as 
  pure 
  a 
  condition 
  as 
  possible 
  

   and 
  that 
  the 
  entire 
  work 
  seems 
  to 
  be 
  very 
  thorough 
  and 
  trust- 
  

   worthy. 
  

  

  In 
  the 
  case 
  of 
  dry 
  air 
  the 
  magnetic 
  susceptibility 
  was 
  deter- 
  

   .mined 
  relatively 
  to 
  pure 
  water 
  as 
  standard, 
  the 
  reliable 
  value 
  

  

  