﻿216 
  Scientific 
  Intelligence. 
  

  

  To 
  establish 
  large 
  beacons 
  or 
  reference 
  points 
  for 
  naval 
  and 
  

   aeronautical 
  purposes 
  the 
  best 
  results 
  were 
  obtained 
  by 
  using 
  a 
  

   quartz 
  mercury 
  arc 
  covered 
  with 
  a 
  screen 
  of 
  nickel 
  glass. 
  The 
  

   small 
  amount 
  of 
  red 
  light 
  which 
  would 
  be 
  transmitted 
  by 
  this 
  

   kind 
  of 
  glass 
  is 
  not 
  emitted 
  by 
  the 
  mercury 
  arc 
  so 
  that, 
  beyond 
  

   very 
  short 
  distances, 
  the 
  screened 
  lamp 
  is 
  not 
  visible 
  to 
  the 
  

   unaided 
  eye. 
  On 
  the 
  other 
  hand, 
  the 
  powerful 
  mercury 
  line 
  at 
  

   A3650 
  falls 
  exactly 
  at 
  the 
  center 
  of 
  the 
  transmission 
  band 
  of 
  

   nickel 
  glass. 
  By 
  employing 
  an 
  appropriate 
  phosphorescent 
  

   detecting 
  apparatus, 
  a 
  lamp 
  arranged 
  in 
  the 
  manner 
  just 
  sug- 
  

   gested 
  has 
  been 
  seen 
  by 
  an 
  observer 
  in 
  an 
  aeroplane 
  flying 
  at 
  an 
  

   elevation 
  of 
  3,000 
  meters. 
  

  

  In 
  addition 
  to 
  the 
  practical 
  applications 
  of 
  the 
  ultra-violet 
  

   lamp, 
  the 
  original 
  paper 
  contains 
  an 
  interesting 
  account 
  of 
  cer- 
  

   tain 
  striking 
  phenomena 
  which 
  occur 
  when 
  various 
  objects 
  are 
  

   illuminated 
  with 
  ultra-violet 
  light 
  of 
  practically 
  a 
  single 
  wave- 
  

   length. 
  For 
  example, 
  the 
  lens 
  of 
  the 
  human 
  eye 
  becomes 
  phos- 
  

   phorescent. 
  The 
  skin 
  assumes 
  a 
  peculiar 
  hue, 
  natural 
  teeth 
  

   phosphoresce 
  brilliantly, 
  false 
  teeth 
  appear 
  black, 
  etc. 
  By 
  

   using 
  a 
  very 
  dilute 
  solution 
  of 
  potassium 
  chromate, 
  the 
  author 
  

   has 
  taken 
  photographs 
  (reproduced 
  in 
  the 
  paper) 
  of 
  his 
  face 
  

   and 
  of 
  one 
  hand. 
  This 
  filter 
  transmits 
  the 
  radiations 
  that 
  excite 
  

   the 
  phosphorescent 
  screen, 
  but 
  it 
  completely 
  absorbs 
  the 
  ultra- 
  

   violet 
  rays 
  reflected 
  and 
  scattered 
  by 
  the 
  skin. 
  Old 
  cicatrices, 
  

   ordinarily 
  invisible, 
  come 
  out 
  with 
  great 
  distinctness. 
  In 
  this 
  

   connection, 
  the 
  author 
  suggests 
  the 
  possibility 
  of 
  taking 
  advan- 
  

   tage 
  of 
  these 
  phenomena 
  in 
  physiological 
  researches. 
  — 
  Jour, 
  de 
  

   Phys., 
  9, 
  77, 
  1919. 
  h. 
  s. 
  u. 
  

  

  7. 
  The 
  Air 
  Propeller; 
  by 
  Frederick 
  Bedell. 
  Pp. 
  96, 
  22 
  

   figures. 
  New 
  York, 
  1919 
  (D. 
  Van 
  Nostrand 
  Co.). 
  — 
  This 
  book 
  

   deals 
  primarily 
  with 
  the 
  working 
  characteristics 
  and 
  theory 
  of 
  

   the 
  air 
  propeller, 
  but 
  it 
  also 
  contains 
  a 
  brief 
  discussion 
  of 
  the 
  

   airplane 
  engine 
  and 
  the 
  power 
  available 
  for 
  airplane 
  propulsion. 
  

   The 
  author's 
  style 
  is 
  lucid 
  and 
  the 
  text 
  is 
  profusely 
  illustrated 
  

   by 
  clear-cut 
  diagrams 
  each 
  of 
  which 
  occupies 
  a 
  full 
  page. 
  The 
  

   appendix 
  comprises 
  a 
  glossary 
  of 
  technical 
  terms, 
  alphabetically 
  

   arranged, 
  and 
  a 
  few 
  supplementary 
  diagrams 
  relating 
  to 
  

   "power 
  required." 
  It 
  is 
  the 
  intention 
  of 
  the 
  author 
  and 
  pub- 
  

   lishers 
  to 
  form 
  six 
  chapters 
  of 
  a 
  new 
  volume 
  by 
  combining 
  the 
  

   present 
  text 
  with 
  the 
  book 
  entitled 
  "Airplane 
  Characteristics" 
  

   (see 
  46, 
  691, 
  1918). 
  h. 
  s. 
  u. 
  

  

  8. 
  Smithsonian 
  Meteorological 
  Tables. 
  Fourth 
  Revised 
  Edi- 
  

   tion. 
  (Publication 
  2493.) 
  Pp. 
  lxxii, 
  261, 
  with 
  107 
  tables 
  and 
  

   an 
  index. 
  Washington, 
  1918. 
  Smithsonian 
  Misc. 
  Collections, 
  

   vol. 
  69, 
  No. 
  1. 
  — 
  This 
  edition 
  has 
  been 
  corrected 
  to 
  January, 
  1918. 
  

   Many 
  of 
  the 
  tables 
  have 
  been 
  subjected 
  to 
  extensive 
  revision 
  

   based 
  upon 
  the 
  new 
  vapor 
  pressure 
  tables, 
  the 
  recomputed 
  table 
  

   of 
  the 
  relative 
  acceleration 
  of 
  gravity 
  at 
  different 
  latitudes, 
  and 
  

  

  