﻿414 
  Scientific 
  Intelligence. 
  

  

  by 
  drilling 
  holes 
  in 
  plates 
  of 
  brass 
  3 
  mm 
  thick. 
  Burner 
  No. 
  1 
  had 
  

   160 
  holes 
  of 
  l 
  mm 
  diameter, 
  the 
  centers 
  being 
  l-5 
  mm 
  apart. 
  They 
  

   were 
  arranged 
  in 
  8 
  rows 
  of 
  20 
  holes 
  each, 
  consecutive 
  rows 
  being 
  

   displaced 
  in 
  such 
  a 
  way 
  that 
  the 
  gap 
  between 
  two 
  names 
  of 
  one 
  

   row 
  was 
  opposite 
  the 
  flame 
  of 
  the 
  next 
  row. 
  By 
  this 
  scheme 
  an 
  

   even 
  distribution 
  of 
  light 
  was 
  obtained 
  in 
  a 
  horizontal 
  direction 
  

   at 
  right 
  angles 
  to 
  the 
  rows 
  of 
  holes. 
  " 
  When 
  a 
  low-pressure 
  gas 
  

   mixture 
  is 
  employed 
  the 
  cones 
  obtained 
  with 
  this 
  burner 
  form 
  an 
  

   almost 
  flat 
  and 
  continuous 
  surface 
  with 
  only 
  slight 
  elevations 
  

   over 
  each 
  hole. 
  Seen 
  end 
  on, 
  the 
  cone 
  region 
  presents 
  the 
  appear- 
  

   ance 
  of 
  a 
  bright 
  thin 
  line. 
  This 
  burner 
  is 
  -therefore 
  particularly 
  

   suited 
  to 
  studying 
  the 
  spectrum 
  of 
  the 
  explosion 
  region." 
  Burner 
  

   No. 
  2 
  had 
  12 
  holes 
  of 
  2 
  mm 
  diameter, 
  arranged 
  in 
  two 
  rows 
  of 
  6 
  

   each, 
  the 
  distances 
  between 
  the 
  axes 
  of 
  the 
  holes 
  being 
  3 
  mm 
  . 
  The 
  

   direction 
  of 
  observation 
  was 
  such 
  as 
  to 
  have 
  five 
  flames 
  behind 
  

   the 
  first 
  one. 
  The 
  gases 
  in 
  the 
  air-coal 
  gas 
  mixture 
  were 
  so 
  pro- 
  

   portioned 
  as 
  to 
  produce 
  blue-colored 
  cones 
  the 
  heights 
  of 
  which 
  

   varied 
  from 
  3 
  to 
  8 
  mm 
  according 
  to 
  the 
  velocity 
  of 
  the 
  gas. 
  The 
  

   burners 
  for 
  oxy-coal 
  gas, 
  oxy-hydrogen, 
  and 
  oxy-acetylene 
  flames 
  

   do 
  not 
  merit 
  attention 
  in 
  this 
  place. 
  

  

  The 
  prism 
  spectrograph 
  was 
  placed 
  in 
  a 
  vertical 
  position 
  in 
  

   order 
  to 
  have 
  the 
  slit 
  horizontal. 
  By 
  using 
  a 
  good 
  Zeiss 
  objective 
  

   (25 
  cm 
  focal 
  length) 
  with 
  the 
  » 
  non-astigmatic 
  spectrograph 
  the 
  

   spectral 
  details 
  of 
  the 
  explosion 
  region 
  of 
  burner 
  No. 
  1 
  or 
  of 
  the 
  

   alternating 
  cones 
  and 
  flame 
  of 
  burner 
  No. 
  2 
  were 
  clearly 
  differen- 
  

   tiated 
  on 
  the 
  spectrograms. 
  

  

  The 
  following 
  provisional 
  classification 
  of 
  the 
  iron 
  lines 
  has 
  

   been 
  adopted 
  by 
  Hemsalech 
  as 
  a 
  consequence 
  of 
  his 
  investiga- 
  

   tions. 
  " 
  Class 
  I. 
  Lines 
  which 
  are 
  emitted 
  by 
  the 
  mantle 
  of 
  the 
  

   air-coal 
  gas 
  flame, 
  and 
  gain- 
  in 
  intensity 
  on 
  passing 
  to 
  the 
  high- 
  

   temperature 
  flames. 
  They 
  are 
  specially 
  sensitive 
  to 
  thermal 
  

   actions, 
  and 
  may 
  be 
  regarded 
  as 
  true 
  temperature 
  lines. 
  Class 
  II. 
  

   Lines 
  which 
  are 
  particularly 
  sensitive 
  to 
  the 
  special 
  chemical 
  

   actions 
  of 
  which 
  the 
  explosion 
  region 
  of 
  the 
  air-coal 
  gas 
  flame 
  is 
  

   the 
  seat. 
  They 
  are 
  also, 
  though 
  feebly, 
  emitted 
  by 
  the 
  outer 
  

   mantle. 
  In 
  the 
  flames 
  of 
  higher 
  temperatures 
  their 
  intensities 
  

   increase, 
  showing 
  that 
  they 
  likewise 
  respond 
  to 
  thermal 
  changes, 
  

   but 
  to 
  a 
  lesser 
  degree 
  than 
  Class 
  I. 
  lines. 
  Class 
  III. 
  This 
  class 
  

   contains 
  the 
  bulk 
  of 
  the 
  cone 
  lines 
  which 
  form 
  what 
  M. 
  de 
  

   Watteville 
  and 
  myself 
  had 
  called 
  the 
  ^> 
  supplementary 
  spectrum." 
  

   For 
  details 
  concerning 
  the 
  structure 
  of 
  the 
  iron 
  spectrum 
  refer- 
  

   ence 
  must 
  be 
  made 
  to 
  the 
  original 
  article. 
  — 
  Phil. 
  Hag., 
  xxxiii, 
  

   p. 
  1, 
  January, 
  1917. 
  h. 
  s. 
  u. 
  

  

  1. 
  The 
  Nature 
  of 
  Matter 
  and 
  Electricity 
  • 
  by 
  Daniel 
  F. 
  

   Comstock 
  and 
  Leonard 
  T. 
  Trotand. 
  Pp. 
  xxii, 
  203, 
  with 
  11 
  

   plates. 
  New 
  York, 
  1917 
  (D. 
  Van 
  Nostrand 
  Co.). 
  — 
  "This 
  book 
  

   attempts 
  to 
  give 
  in 
  broad, 
  schematic 
  form 
  the 
  conception 
  of 
  the 
  

   structure 
  of 
  the 
  material 
  universe 
  which 
  has 
  developed 
  in 
  the 
  

   minds 
  of 
  modern 
  students 
  of 
  physical 
  science." 
  The 
  text 
  is 
  

   divided 
  into 
  two 
  parts, 
  the 
  first 
  of 
  which 
  is 
  based 
  on 
  a 
  series 
  of 
  

  

  