﻿Properties 
  of 
  Films 
  of 
  Magnetic 
  Metals. 
  

  

  859 
  

  

  Table 
  XVII. 
  and 
  figure 
  15 
  embody 
  the 
  results 
  from 
  two 
  

   films, 
  one 
  of 
  measured 
  thickness 
  (48 
  x 
  10~ 
  7 
  cm.), 
  the 
  other 
  

   calculated 
  from 
  its 
  magnetic 
  rotation 
  (24 
  x 
  10~ 
  7 
  cm.) 
  . 
  The 
  

   results 
  show 
  that 
  the 
  ellipticity 
  is 
  proportional 
  to 
  the 
  thickness, 
  

   as 
  should 
  be 
  expected 
  since 
  there 
  is 
  no 
  appreciable 
  ellipticity 
  

   in 
  the 
  reflected 
  light. 
  The 
  extinction 
  values 
  are 
  found 
  to 
  be 
  

   only 
  about 
  one-third 
  those 
  of 
  the 
  corresponding 
  type 
  of 
  iron. 
  

   The 
  refractive 
  indices 
  as 
  given 
  were 
  obtained 
  from 
  one 
  series 
  

   of 
  observations. 
  They 
  could 
  be 
  only 
  approximately 
  determined 
  

   owing 
  to 
  the 
  small 
  magnitudes 
  involved. 
  They 
  are 
  about 
  

   fifty 
  per 
  cent, 
  higher 
  than 
  those 
  of 
  dark 
  cobalt, 
  and 
  like 
  

   them 
  remain 
  about 
  the 
  same 
  value 
  throughout 
  the 
  spectrum. 
  

  

  Table 
  XVII.— 
  Metallic 
  Cobalt. 
  

  

  Thickness 
  : 
  JS 
  T 
  o. 
  7, 
  48 
  X 
  10" 
  7 
  ; 
  No. 
  8, 
  24 
  x 
  10~ 
  7 
  

   Field 
  : 
  14,000 
  c.G.s. 
  

  

  cm. 
  

  

  

  Rotation 
  

  

  v^ 
  in— 
  5 
  

  

  Ellipticity 
  

  

  Transmission 
  

  

  

  

  Wave- 
  

  

  Thickness 
  ^ 
  

  

  Thickness 
  ' 
  

  

  (per 
  cent.). 
  

  

  Extinct. 
  

  

  Eefrac. 
  

  

  length. 
  

  

  

  

  

  

  

  xio- 
  6 
  . 
  

  

  Index. 
  

  

  No. 
  7. 
  

  

  No. 
  8. 
  

  

  No. 
  7. 
  ' 
  No. 
  8. 
  

  

  No. 
  7. 
  

  

  No. 
  8. 
  

  

  440 
  

  

  

  5-6 
  

  

  

  5050 
  

  

  

  1-9 
  

  

  

  

  460 
  

  

  5-6 
  

  

  5-8 
  

  

  4800 
  

  

  4800 
  

  

  

  2-0 
  

  

  

  

  480 
  

  

  

  5-8 
  

  

  

  4600 
  

  

  

  24 
  

  

  

  

  500 
  

  

  5-7 
  

  

  5-8 
  

  

  4400 
  

  

  4450 
  

  

  T7 
  

  

  2-2 
  

  

  1T1 
  

  

  2-8 
  

  

  520 
  

  

  

  5-9 
  

  

  | 
  4300 
  

  

  •19 
  

  

  23 
  

  

  1-08 
  

  

  2-8 
  

  

  540 
  

  

  6-0 
  

  

  6-0 
  

  

  3960 
  1 
  4100 
  

  

  •20 
  

  

  23 
  

  

  1-06 
  

  

  32 
  

  

  560 
  

  

  

  62 
  

  

  i 
  3850 
  

  

  •22 
  

  

  25 
  

  

  105 
  

  

  3-3 
  

  

  580 
  

  

  63 
  

  

  63 
  

  

  3740 
  3780 
  

  

  •23 
  

  

  26 
  

  

  1-05 
  

  

  3-6 
  

  

  600 
  

  

  

  

  6-4 
  

  

  3430 
  

  

  •25 
  

  

  2-6 
  

  

  1-02 
  

  

  31 
  

  

  620 
  

  

  

  

  

  

  •27 
  

  

  2-7 
  

  

  TOO 
  

  

  3-2 
  

  

  630 
  

  

  68 
  

  

  6-6 
  

  

  

  3200 
  

  

  

  

  

  

  640 
  

  

  

  

  

  

  •29 
  

  

  2-8 
  

  

  0-98 
  

  

  2-7 
  

  

  660 
  

  

  

  6-8 
  

  

  

  2880 
  

  

  •30 
  

  

  2-9 
  

  

  0-98 
  

  

  34 
  

  

  15. 
  Nickel. 
  

  

  As 
  already 
  stated 
  only 
  electrolytic 
  nickel 
  showed 
  more 
  

   than 
  a 
  mere 
  trace 
  of 
  optical 
  activity 
  in 
  the 
  magnetic 
  field. 
  

   This 
  is 
  rather 
  remarkable, 
  for 
  brilliant 
  nickel 
  mirrors 
  are 
  

   produced 
  by 
  the 
  glow 
  current, 
  and 
  by 
  varying 
  the 
  tempera- 
  

   ture, 
  films 
  of 
  any 
  hardness, 
  all 
  of 
  which 
  show 
  metallic 
  

   reflexion, 
  may 
  be 
  obtained. 
  

  

  Table 
  XVIII. 
  (p. 
  860) 
  contains 
  the 
  results 
  obtained 
  from 
  

   two 
  different 
  films 
  o£ 
  electrolytic 
  nickel, 
  one 
  (No. 
  40) 
  possessing 
  

   a 
  measured 
  thickness 
  of 
  71 
  x 
  10~ 
  7 
  cm., 
  the 
  other 
  (No. 
  41) 
  a 
  

   calculated 
  thickness 
  of 
  37'4 
  X 
  10 
  -7 
  . 
  The 
  thickness 
  of 
  the 
  

   second 
  film, 
  as 
  calculated 
  from 
  its 
  rotation, 
  is 
  considered 
  

  

  