﻿Geology. 
  425 
  

  

  the 
  presence 
  of 
  hydrogen, 
  or 
  moisture 
  and 
  acid." 
  — 
  Proc. 
  Roy. 
  

   Soc, 
  Feb. 
  21, 
  1895 
  : 
  Chem. 
  News, 
  lxxi, 
  115, 
  March, 
  1895. 
  

  

  G. 
  F. 
  B. 
  

  

  4. 
  On 
  the 
  Spark 
  Spectrum 
  of 
  Argon 
  as 
  it 
  appears 
  in 
  the 
  Spark 
  

   Spectrum 
  of 
  Air. 
  — 
  On 
  the 
  21st 
  of 
  March, 
  Hartley 
  read 
  to 
  the 
  

   Royal 
  Society 
  a 
  paper 
  pointing 
  out 
  that 
  certain 
  lines 
  obtained 
  by 
  

   himself 
  and 
  Adeney 
  in 
  1884, 
  in 
  their 
  photographs 
  of 
  the 
  air 
  

   spectrum, 
  now 
  appear 
  to 
  be 
  due 
  to 
  argon. 
  In 
  their 
  investiga- 
  

   tions, 
  they 
  used 
  electrodes 
  of 
  aluminum, 
  copper, 
  platinum 
  and 
  

   palladium, 
  and 
  a 
  condensed 
  spark 
  produced 
  with 
  a 
  coil 
  with 
  a 
  

   Leyden 
  jar 
  in 
  circuit 
  ; 
  the 
  partial 
  pressure 
  — 
  since 
  argon 
  constitutes 
  

   about 
  1 
  per 
  cent 
  of 
  the 
  atmosphere 
  — 
  being 
  about 
  7'5 
  mm 
  . 
  Since 
  

   these 
  are 
  practically 
  the 
  conditions 
  which 
  as 
  Crookes 
  has 
  shown 
  

   give 
  the 
  brightest 
  and 
  purest 
  spectrum 
  of 
  argon, 
  the 
  author 
  

   thought 
  it 
  reasonable 
  to 
  expect 
  the 
  recognition 
  of 
  the 
  blue 
  and 
  

   ultra-violet 
  lines 
  of 
  this 
  substance 
  among 
  some 
  of 
  the 
  weaker 
  

   lines 
  in 
  the 
  spectrum 
  of 
  air. 
  A 
  table 
  containing 
  the 
  wave 
  lengths 
  

   of 
  50 
  or 
  more 
  lines 
  thus 
  observed 
  in 
  the 
  air 
  spectrum 
  is 
  given 
  in 
  

   the 
  paper, 
  with 
  the 
  characteristic 
  lines 
  of 
  the 
  blue 
  and 
  the 
  red 
  

   spectra 
  of 
  argon 
  in 
  parallel 
  columns 
  for 
  comparison. 
  He 
  con- 
  

   siders 
  of 
  little 
  importance 
  the 
  fact 
  that 
  argon 
  gives 
  two 
  spectra 
  ; 
  

   the 
  red 
  being 
  apparently 
  the 
  spectrum 
  of 
  the 
  first 
  order 
  or 
  of 
  the 
  

   corresponding 
  lower 
  temperature, 
  while 
  the 
  blue 
  is 
  the 
  line 
  spec- 
  

   trum 
  at 
  the 
  higher 
  temperature. 
  " 
  It 
  is 
  therefore 
  more 
  likely," 
  

   he 
  concludes, 
  " 
  that 
  argon 
  is 
  one 
  substance 
  and 
  not 
  two. 
  Whether 
  

   it 
  is 
  a 
  compound 
  or 
  an 
  element 
  is 
  a 
  question 
  into 
  which 
  the 
  fol- 
  

   lowing 
  considerations 
  may 
  enter. 
  There 
  are 
  at 
  present 
  no 
  gase- 
  

   ous 
  substances 
  known 
  which 
  can 
  withstand 
  the 
  temperature 
  of 
  

   the 
  condensed 
  spark 
  without 
  exhibiting 
  the 
  spectra 
  of 
  one 
  or 
  

   other 
  of 
  the 
  elements 
  of 
  which 
  it 
  is 
  composed. 
  If 
  therefore, 
  

   argon 
  were 
  N 
  3 
  it 
  would 
  disclose 
  the 
  spectrum 
  of 
  nitrogen. 
  As 
  

   the 
  spectrum 
  is 
  not 
  that 
  of 
  any 
  known 
  substance 
  it 
  follows 
  that 
  

   if 
  a 
  compound, 
  it 
  must 
  be 
  a 
  compound 
  of 
  a 
  new 
  element." 
  — 
  

   Proc. 
  Roy. 
  Soc, 
  March 
  21, 
  1895. 
  (From 
  advance 
  sheets 
  received 
  

   from 
  the 
  author.) 
  g. 
  f. 
  b. 
  

  

  II. 
  Geology. 
  

  

  1. 
  Reconnoissance 
  of 
  the 
  Bahamas 
  and 
  of 
  the 
  elevated 
  reefs 
  of 
  

   Cuba 
  in 
  the 
  Steam 
  Yacht 
  " 
  Wild 
  Duck" 
  January 
  to 
  April, 
  

   1893; 
  by 
  Alexander 
  Agassiz. 
  204 
  pp. 
  8vo, 
  with 
  41 
  plates. 
  

   Bulletin 
  of 
  the 
  Mus. 
  Comp. 
  Zool. 
  of 
  Harvard 
  College, 
  vol. 
  xxvi, 
  

   Xo. 
  1. 
  — 
  The 
  coral 
  reefs 
  of 
  the 
  West 
  India 
  seas 
  may 
  be 
  regarded 
  

   as 
  the 
  subject 
  of 
  Prof. 
  Agassiz's 
  Report, 
  although 
  only 
  the 
  

   Bahamas 
  and 
  Cuba 
  are 
  mentioned 
  in 
  the 
  title. 
  For, 
  after 
  the 
  

   very 
  fuU 
  descriptions 
  relating 
  to 
  the 
  region 
  of 
  more 
  special 
  

   study, 
  the 
  report 
  devotes 
  20 
  of 
  its 
  200 
  pages 
  to 
  the 
  coral 
  reefs 
  

   and 
  banks 
  of 
  the 
  Caribbean 
  district, 
  including 
  therein 
  the 
  reefs 
  

   of 
  the 
  north 
  shore 
  of 
  South 
  America, 
  the 
  Yucatan 
  Bank 
  and 
  

   British 
  Honduras. 
  The 
  origin 
  of 
  coral 
  reefs 
  is 
  the 
  concluding 
  

  

  Am. 
  Jour. 
  Sci.— 
  Third 
  Series, 
  Yol. 
  XLIX, 
  No. 
  293.— 
  Mat, 
  1895. 
  

   28 
  

  

  