﻿1875.] 
  

  

  the 
  Heat 
  of 
  Sunshine 
  at 
  London. 
  

  

  581 
  

  

  Table 
  in. 
  

  

  Containing 
  yearly 
  values 
  of 
  the 
  heat 
  of 
  Sunshine. 
  

  

  Mean 
  date. 
  Amount. 
  

  

  June 
  1855 
  11-258 
  

  

  Dec. 
  1855 
  4-545 
  

  

  June 
  1856 
  2-318 
  

  

  Dec. 
  1856 
  2-316 
  

  

  June 
  1857 
  1-538 
  

  

  Dec. 
  1857 
  

  

  June 
  1858 
  42-438 
  

  

  Dec. 
  1858 
  43*607 
  

  

  June 
  1859 
  51-521 
  

  

  Dec. 
  1859 
  43-858 
  

  

  June 
  1860 
  32-423 
  

  

  Dec. 
  1860 
  29-826 
  

  

  June 
  1861 
  27*368 
  

  

  Dec. 
  1861 
  25-599 
  

  

  June 
  1862 
  29-509 
  

  

  Dec. 
  1862 
  26-795 
  

  

  June 
  1863 
  30-115 
  

  

  Dec. 
  1863 
  28-325 
  

  

  June 
  1864 
  19-258 
  

  

  Dec. 
  1864 
  25-209 
  

  

  Mean 
  date. 
  Amount. 
  

  

  June 
  1865 
  28-111 
  

  

  Dec. 
  1865 
  24-825 
  

  

  June 
  1866 
  25-790 
  

  

  Dec. 
  1866 
  28-790 
  

  

  June 
  1867 
  33-245 
  

  

  Dec. 
  1867 
  38-895 
  

  

  June 
  1868 
  29-190 
  

  

  Dec. 
  1868 
  20-525 
  

  

  June 
  1869 
  31-213 
  

  

  Dec. 
  1869 
  34-193 
  

  

  June 
  1870 
  31-750 
  

  

  Dec. 
  1870 
  37-680 
  

  

  June 
  1871 
  32-465 
  

  

  Dec. 
  1871 
  21-955 
  

  

  June 
  1872 
  19-675 
  

  

  Dec. 
  1872 
  18-158 
  

  

  June 
  1873 
  29-191 
  

  

  Dec. 
  1873 
  34-443 
  

  

  June 
  1874 
  29-478 
  

  

  The 
  first 
  five 
  of 
  these 
  values 
  must 
  be 
  treated 
  by 
  themselves, 
  inasmuch 
  

   as 
  the 
  lens 
  was 
  a 
  water 
  one. 
  They 
  point 
  to 
  a 
  minimum 
  of 
  solar-heat 
  

   action 
  in 
  1856 
  and 
  1857 
  ; 
  this 
  agrees 
  very 
  well 
  with 
  the 
  minimum 
  of 
  

   sun-spot 
  action 
  which 
  took 
  place 
  in 
  1856. 
  

  

  Of 
  the 
  remaining 
  thirty-three 
  values 
  the 
  mean 
  is 
  30-468. 
  

   Now 
  there 
  was 
  a 
  maximum 
  of 
  sun-spot 
  frequency 
  in 
  1859 
  and 
  1870, 
  

   and 
  a 
  minimum 
  about 
  the 
  end 
  of 
  1866 
  or 
  beginning 
  of 
  1867. 
  

  

  Let 
  us 
  take 
  the 
  values 
  of 
  sun-heat 
  action 
  about 
  these 
  dates, 
  and 
  see 
  

   if 
  there 
  be 
  any 
  correspondence. 
  We 
  have 
  sun-heat 
  action, 
  mean 
  date 
  

   Dec. 
  1858=43-607 
  

   June 
  1859=51-521 
  

   Dec. 
  1859=43-858 
  

  

  Mean 
  of 
  the 
  above 
  46-329, 
  

  

  a 
  value 
  which 
  is 
  greater 
  than 
  the 
  average. 
  

   Again 
  we 
  have 
  sun-heat 
  action, 
  mean 
  date 
  

   Dec. 
  1869=34-193 
  

   June 
  1870=31-750 
  

   Dec. 
  1870=37-680 
  

  

  The 
  mean 
  of 
  which 
  is 
  34-541, 
  

  

  which 
  is 
  also 
  greater 
  than 
  the 
  average, 
  although 
  the 
  difference 
  is 
  not 
  so 
  

   decided. 
  

  

  Lastly 
  we 
  have 
  sun-heat 
  action, 
  mean 
  date 
  

   June 
  1866=25-790 
  

   Dec. 
  1866 
  = 
  28-790 
  

   June 
  1867=33-245 
  

  

  The 
  mean 
  of 
  which 
  is 
  29-275, 
  

  

  which 
  is 
  less 
  than 
  the 
  average. 
  

  

  