﻿Visibility 
  of 
  Radiation. 
  

  

  179 
  

  

  Nutting 
  are 
  given, 
  as 
  well 
  as 
  the 
  two 
  sets 
  of 
  values 
  published 
  

   by 
  Coblentz. 
  The 
  greatest 
  differences 
  in 
  these 
  values 
  occur 
  

   in 
  the 
  region 
  of 
  the 
  longer 
  wave-lengths 
  and, 
  as 
  has 
  been 
  

   said, 
  are 
  probably 
  due 
  to 
  the 
  different 
  types 
  of 
  burners 
  used. 
  

  

  Table 
  II. 
  — 
  Comparative 
  Visibility 
  Results. 
  

  

  fave- 
  

   ngth. 
  

  

  Mean 
  V 
  

  

  from 
  

   Table 
  I. 
  

  

  Coblentz 
  

  

  data 
  publ. 
  

  

  1911. 
  

  

  Coblentz 
  

  

  data 
  publ. 
  

  

  1916. 
  

  

  Nutting's 
  

   Mean. 
  

  

  Ives's 
  

   Mean. 
  

  

  Computed 
  

  

  from 
  

   formula. 
  

  

  •49 
  

  

  •175 
  

  

  •172 
  

  

  •172 
  

  

  227 
  

  

  •235 
  

  

  •232 
  

  

  •50 
  

  

  •289 
  

  

  •283 
  

  

  •275 
  

  

  •330 
  

  

  •363 
  

  

  •358 
  

  

  •51 
  

  

  •475 
  

  

  •471 
  

  

  •474 
  

  

  •477 
  

  

  •596 
  

  

  •514 
  

  

  •52 
  

  

  •702 
  

  

  •705 
  

  

  •686 
  

  

  •671 
  

  

  •794 
  

  

  •675 
  

  

  •53 
  

  

  •842 
  

  

  •851 
  

  

  •841 
  

  

  •835 
  

  

  •912 
  

  

  •824 
  

  

  •54 
  

  

  •950 
  

  

  •947 
  

  

  •935 
  

  

  •944 
  

  

  •977 
  

  

  •933 
  

  

  •55 
  

  

  •990 
  

  

  •988 
  

  

  •993 
  

  

  •995 
  

  

  1-000 
  

  

  •994 
  

  

  •56 
  

  

  •977 
  

  

  •982 
  

  

  •985 
  

  

  •993 
  

  

  •990 
  

  

  •993 
  

  

  •57 
  

  

  •898 
  

  

  •926 
  

  

  •935 
  

  

  •944 
  

  

  •948 
  

  

  •939 
  

  

  •58 
  

  

  •807 
  

  

  •825 
  

  

  •836 
  

  

  •851 
  

  

  •875 
  

  

  •839 
  

  

  •59 
  

  

  •676 
  

  

  •693 
  

  

  •710 
  

  

  •735 
  

  

  •763 
  

  

  •717 
  

  

  •60 
  

  

  •548 
  

  

  •552 
  

  

  •580 
  

  

  •605 
  

  

  •635 
  

  

  •585 
  

  

  •61 
  

  

  •409 
  

  

  •417 
  

  

  •446 
  

  

  •468 
  

  

  •509 
  

  

  •456 
  

  

  •62 
  

  

  •293 
  

  

  •294 
  

  

  •319 
  

  

  •342 
  

  

  •387 
  

  

  •343 
  

  

  •63 
  

  

  •194 
  

  

  •185 
  

  

  •214 
  

  

  •247 
  

  

  •272 
  

  

  •235 
  

  

  •64 
  

  

  •127 
  

  

  •125 
  

  

  •140 
  

  

  •163 
  

  

  •175 
  

  

  •158 
  

  

  Table 
  III. 
  — 
  Spectral 
  Energy 
  Distribution 
  of 
  

   an 
  Acetylene 
  Flame. 
  

  

  Wave-length 
  

   in 
  /x. 
  

  

  Nutting 
  data 
  

  

  •48 
  

  

  111 
  

  

  •50 
  

  

  14-4 
  

  

  •52 
  

  

  18-4 
  

  

  •54 
  

  

  232 
  

  

  •55 
  

  

  261 
  

  

  •56 
  

  

  29-1 
  

  

  •58 
  

  

  36-2 
  

  

  •60 
  

  

  44-2 
  

  

  •62 
  

  

  53-7 
  

  

  •64 
  

  

  638 
  

  

  •66 
  

  

  746 
  

  

  •68 
  

  

  86-1 
  

  

  •70 
  

  

  982 
  

  

  Coblentz 
  

  

  Coblentz 
  

  

  old 
  data. 
  

  

  new 
  data 
  

  

  16-5 
  

  

  170 
  

  

  21-7 
  

  

  21-9 
  

  

  27-6 
  

  

  27-9 
  

  

  34-8 
  

  

  35-0 
  

  

  

  38-9 
  

  

  43-7 
  

  

  42-9 
  

  

  54-0 
  

  

  522 
  

  

  66-3 
  

  

  62-1 
  

  

  80-5 
  

  

  730 
  

  

  96-5 
  

  

  84-7 
  

  

  1128 
  

  

  974 
  

  

  1301 
  

  

  110-9 
  

  

  147-0 
  

  

  124-6 
  

  

  The 
  spectral 
  energy 
  distribution 
  of 
  acetylene 
  is 
  probably 
  

   better 
  known 
  than 
  that 
  of 
  any 
  other 
  light 
  source, 
  and 
  the 
  

  

  