﻿Chemistry 
  and 
  Physics. 
  231 
  

  

  is 
  the 
  study 
  of 
  the 
  long 
  struggle, 
  the 
  failures 
  and 
  the 
  triumphs 
  

   of 
  the 
  men 
  who 
  have 
  made 
  this 
  science 
  for 
  us." 
  The 
  first 
  part 
  

   describes 
  the 
  genesis 
  of 
  chemistry, 
  the 
  second 
  treats 
  of 
  the 
  alchem- 
  

   ists, 
  the 
  third 
  considers 
  qualitative 
  ehemistry, 
  the 
  fourth 
  has 
  to 
  

   do 
  with 
  quantitative 
  chemistry, 
  the 
  fifth 
  discusses 
  structural 
  

   chemistry, 
  and 
  the 
  sixth 
  is 
  devoted 
  to 
  special 
  branches 
  of 
  chem- 
  

   istry. 
  Within 
  so 
  small 
  a 
  compass, 
  it 
  is 
  evident 
  that 
  but 
  a 
  

   limited 
  treatment 
  of 
  so 
  broad 
  a 
  subject 
  can 
  be 
  given. 
  The 
  book 
  

   appears 
  to 
  be 
  well 
  written 
  and 
  seems 
  adapted 
  to 
  be 
  of 
  service 
  in 
  

   those 
  institutions 
  where 
  the 
  history 
  of 
  chemistry 
  forms 
  a 
  part 
  of 
  

   the 
  prescribed 
  course. 
  g. 
  f. 
  b. 
  

  

  5. 
  Multiple 
  Resonance. 
  — 
  Various 
  investigations 
  have 
  been 
  

   made 
  in 
  the 
  subject 
  of 
  the 
  interference 
  of 
  electrical 
  waves; 
  and 
  

   apparently 
  the 
  diffraction 
  of 
  these 
  waves 
  has 
  been 
  satisfactorily 
  

   shown. 
  V. 
  Bjeeknes 
  points 
  out, 
  however, 
  that 
  an 
  important 
  

   difference 
  exists 
  between 
  the 
  phenomena 
  of 
  the 
  interference 
  of 
  

   light 
  waves 
  and 
  those 
  of 
  electrical 
  waves. 
  In 
  the 
  case 
  of 
  light 
  

   we 
  observe 
  the 
  phenomena 
  by 
  means 
  of 
  instruments 
  which 
  may 
  

   be 
  termed 
  indifferent, 
  that 
  is, 
  instruments 
  which 
  do 
  not 
  influence 
  

   or 
  are 
  not 
  influenced 
  by 
  the 
  source 
  emitting 
  the 
  waves. 
  Whereas 
  

   in 
  electrical 
  resonance, 
  the 
  resonator 
  is 
  especially 
  sensitive 
  to 
  the 
  

   various 
  conditions 
  of 
  the 
  electrical 
  oscillation. 
  In 
  general 
  the 
  

   oscillator 
  is 
  more 
  quickly 
  damped 
  than 
  the 
  resonator. 
  Damped 
  

   waves 
  do 
  not 
  in 
  general 
  show 
  sharp 
  nodes. 
  Various 
  conditions 
  

   may 
  arise, 
  which 
  depend 
  upon 
  the 
  circumstances 
  of 
  damping. 
  If 
  

   the 
  resonator 
  in 
  comparison 
  with 
  the 
  oscillator 
  is 
  strongly 
  damped, 
  

   the 
  ventral 
  segments 
  and 
  nodal 
  points 
  are 
  relatively 
  well 
  defined. 
  

   While 
  the 
  resonator 
  is 
  relatively 
  insensitive 
  to 
  a 
  stimulus 
  of 
  its 
  

   own 
  peculiar 
  rate 
  of 
  oscillation. 
  On 
  the 
  other 
  hand, 
  if 
  the 
  oscil- 
  

   lator 
  is 
  strongly 
  damped 
  and 
  the 
  resonator 
  relatively 
  weakly 
  

   damped, 
  as 
  is 
  the 
  condition 
  in 
  most 
  of 
  Hertz's 
  apparatus, 
  the 
  

   ventral 
  segments 
  and 
  nodes 
  are 
  not 
  clearly 
  defined, 
  while 
  the 
  

   resonator 
  is 
  especially 
  sensitive 
  to 
  the 
  excitement 
  of 
  its 
  own 
  

   peculiar 
  oscillations. 
  In 
  the 
  experiments 
  with 
  a 
  diffraction 
  grating 
  

   these 
  peculiarities 
  must 
  be 
  considered. 
  What 
  may 
  seem 
  to 
  be 
  

   spectral 
  dispersion 
  may 
  be 
  only 
  the 
  multiple 
  resonance 
  of 
  the 
  

   instrument. 
  — 
  Ann. 
  der 
  Physik 
  nnd 
  Chemie, 
  No. 
  I, 
  1895, 
  pp. 
  58-63. 
  

  

  J. 
  T. 
  

  

  6. 
  Spectrum 
  analyses 
  of 
  the 
  color 
  of 
  the 
  water 
  in 
  the 
  Blue 
  

   Grotto, 
  of 
  the 
  Swiss 
  ice 
  holes 
  and 
  of 
  the 
  Yellowstone 
  Springs. 
  — 
  

   H. 
  W. 
  Vogel, 
  twenty 
  years 
  ago, 
  examined 
  with 
  a 
  spectroscope 
  

   the 
  light 
  in 
  the 
  blue 
  grotto 
  at 
  Capri. 
  The 
  water 
  inside 
  and 
  out- 
  

   side 
  the 
  grotto 
  showed 
  an 
  absorption 
  band 
  between 
  the 
  Frauen- 
  

   hofer 
  lines 
  b 
  and 
  E 
  together 
  with 
  a 
  disappearance 
  of 
  the 
  red 
  end 
  

   of 
  the 
  spectrum 
  up 
  to 
  the 
  line 
  D. 
  'During 
  the 
  present 
  year 
  he 
  

   has 
  had 
  an 
  opportunity 
  to 
  examine 
  the 
  water 
  and 
  the 
  light 
  of 
  the 
  

   walls 
  of 
  the 
  other 
  grottos 
  (green 
  and 
  red) 
  of 
  the 
  island. 
  He 
  

   found 
  no 
  trace 
  of 
  the 
  absorption 
  band 
  which 
  he 
  had 
  noticed 
  in 
  

   the 
  blue 
  grotto 
  in 
  his 
  examination 
  of 
  the 
  walls 
  and 
  water 
  in 
  these 
  

   colored 
  grottos. 
  The 
  red 
  end 
  of 
  the 
  spectrum, 
  however, 
  was 
  

  

  