﻿66 
  REPORT 
  UNITED 
  STATES 
  ENTOMOLOGICAL 
  COMMISSION. 
  

  

  magnetism, 
  electrical 
  activity, 
  periodical 
  variations 
  in 
  temperature, 
  

   periodicity 
  of 
  wind 
  disturbance, 
  and 
  annual 
  rainfall 
  have 
  especially 
  

   occupied 
  attention 
  in 
  this 
  respect 
  5 
  and 
  their 
  cycles 
  following 
  respon- 
  

   sively 
  on 
  the 
  changes 
  in 
  the 
  bright 
  photosphere 
  surrounding 
  the 
  sun, 
  

   have 
  been 
  observed, 
  registered, 
  and 
  drawn 
  up 
  in 
  tables. 
  From 
  these 
  

   indices 
  we 
  may 
  now 
  glean 
  that 
  as 
  this 
  bright 
  atmosphere 
  of 
  light 
  every 
  

   eleven 
  years 
  or 
  so 
  becomes 
  ragged 
  with 
  spots 
  and 
  then 
  replenishes 
  its 
  

   shining,^ 
  so 
  do 
  cold 
  and 
  warm 
  seasons, 
  cyclones 
  and 
  rainfall, 
  disturb- 
  

   ances 
  along 
  the 
  electric 
  wire, 
  compass 
  oscillations, 
  auroral 
  displays, 
  

   and 
  other 
  sun 
  symptoms 
  in 
  our 
  sky 
  and 
  soil, 
  follow 
  each 
  other 
  in 
  due 
  

   sequence. 
  Medical 
  science, 
  too, 
  has 
  not 
  been 
  oblivious 
  of 
  these 
  sun 
  

   periods, 
  and 
  not 
  a 
  few 
  attempts 
  have 
  been 
  made 
  to 
  correlate 
  them 
  with 
  

   seasons 
  of 
  famine, 
  plague, 
  cholera, 
  and 
  other 
  epidemic 
  visitations. 
  (A 
  

   pestilential 
  cj-cle, 
  according 
  to 
  Dr. 
  John 
  Parkin, 
  extended 
  from 
  1600 
  

   until 
  about 
  1700, 
  and 
  another 
  began 
  with 
  the 
  nineteenth 
  century. 
  

   Journal 
  of 
  Science, 
  August, 
  1881.) 
  

  

  In 
  the 
  cloud-driven 
  and 
  inconstant 
  climate 
  of 
  northern 
  Europe 
  the 
  

   procession 
  of 
  the 
  seasons 
  daily 
  chronicled 
  in 
  the 
  horizontal 
  swiug 
  and 
  

   vertical 
  dip 
  of 
  the 
  compass 
  needle, 
  would- 
  appear 
  from 
  all 
  accounts 
  to 
  

   be 
  both 
  complex 
  and 
  difficult 
  to 
  unravel 
  ; 
  and 
  the 
  same 
  remark, 
  I 
  think, 
  

   applies 
  to 
  the 
  tracts 
  of 
  northern 
  America. 
  Indeed, 
  it 
  would 
  appear 
  

   hitherto 
  as 
  though 
  the 
  electrical 
  storms 
  and 
  increasing 
  frequency 
  in 
  the 
  

   display 
  of 
  auroral 
  lights, 
  the 
  wind 
  commotions, 
  and 
  perhaps 
  rainfall 
  

   coming 
  on 
  about 
  the 
  maximum 
  period 
  of 
  sun-spots, 
  and 
  the 
  heat 
  waves 
  

   characterizing 
  the 
  minimum 
  period 
  are 
  to 
  be 
  considered 
  as 
  the 
  most 
  

   obvious 
  and 
  best 
  established 
  features 
  in 
  our 
  solar 
  drama. 
  Electrical 
  

   storms 
  were 
  felt 
  along 
  the 
  English 
  telegraphic 
  wires 
  in 
  the 
  years 
  1848 
  

   and 
  1859, 
  and 
  again, 
  last 
  August 
  (1881), 
  we 
  hear 
  of 
  the 
  compass 
  needle 
  

   being 
  affected 
  (English 
  Mechanic, 
  of 
  Friday, 
  December 
  9, 
  1881). 
  During 
  

  

  ^ 
  Sir 
  John 
  F. 
  17. 
  JSersclieVs 
  description 
  of 
  the 
  sun 
  spots. 
  

   When 
  viewed 
  Tvitli 
  powerful 
  . 
  telescopes, 
  piovided 
  with 
  colored 
  glasses 
  to 
  take 
  off 
  the 
  heat, 
  which 
  

   would 
  otherwise 
  injure 
  the 
  eyesight, 
  the 
  sun 
  is 
  observed 
  to 
  have 
  Irequently 
  large 
  and 
  perfectly 
  black 
  

   spots 
  upon 
  it, 
  surrounded 
  with 
  a 
  kind 
  of 
  border, 
  less 
  completely 
  dark. 
  Th«se 
  spots 
  are, 
  however, 
  not 
  

   permanent. 
  When 
  watched 
  from 
  day 
  to 
  day, 
  or 
  even 
  from 
  hour 
  to 
  hour, 
  they 
  appear 
  to 
  enlarge 
  or 
  con- 
  

   tract, 
  to 
  change 
  their 
  forms, 
  and 
  at 
  length 
  to 
  disappear 
  altogether, 
  or 
  to 
  break 
  out 
  anew 
  in 
  parts 
  of 
  the' 
  

   surface 
  where 
  none 
  were 
  before. 
  In 
  such 
  cases 
  the 
  central 
  dark 
  spot 
  always 
  contracts 
  into 
  a 
  point, 
  

   and 
  vanishes 
  before 
  the 
  border. 
  Occasionally 
  they 
  break 
  up 
  or 
  divide 
  into 
  two 
  more, 
  and 
  in 
  those 
  

   offer 
  every 
  evidence 
  of 
  that 
  extreme 
  mobility 
  which 
  belongs 
  only 
  to 
  the 
  fluid 
  state, 
  and 
  of 
  that 
  exces- 
  

   sively 
  violent 
  agitation 
  which 
  seems 
  only 
  compatible 
  with 
  the 
  atmospheric 
  or 
  gaseous 
  state 
  of 
  mat- 
  

   ter. 
  Their 
  size 
  has 
  been 
  computed 
  at 
  from 
  465 
  to 
  45,000 
  miles 
  linear 
  diameter, 
  and 
  some 
  are 
  said 
  to 
  

   reach 
  a 
  greater 
  extent. 
  That 
  part 
  of 
  the 
  sun's 
  disk 
  not 
  occupied 
  by 
  spots 
  is 
  far 
  from 
  uniformly 
  

   bright. 
  Its 
  ground 
  is 
  finely 
  mottled 
  with 
  an 
  appearance 
  of 
  minnte, 
  dark 
  spots 
  or 
  pores, 
  which, 
  when 
  

   attentively 
  watched, 
  are 
  found 
  to 
  be 
  in 
  a 
  constant 
  state 
  of 
  change. 
  There 
  is 
  nothing 
  which 
  repre- 
  

   sents 
  so 
  faithfully 
  this 
  appearance 
  as 
  the 
  slow 
  subsidence 
  of 
  some 
  flocculent 
  chemical 
  precipitates 
  in 
  

   a 
  transparent 
  fluid, 
  when 
  viewed 
  peipendicularly 
  from 
  above. 
  Lastly, 
  in 
  the 
  neighborhood 
  of 
  gieat 
  

   spots, 
  or 
  extensive 
  groups 
  of 
  them, 
  large 
  spaces 
  of 
  the 
  surface 
  are 
  often 
  observed 
  to 
  be 
  covered 
  with 
  

   strongly 
  marked 
  curved 
  or 
  branching 
  streaks 
  more 
  luminous 
  than 
  the 
  rest, 
  and 
  among 
  these, 
  if 
  not 
  

   already 
  existing, 
  spots 
  frequently 
  break 
  out. 
  Only 
  one 
  notion 
  among 
  the 
  many 
  that 
  have 
  been 
  

   broached 
  has 
  gained 
  acceptance 
  in 
  regard 
  to 
  the 
  spots, 
  namely, 
  that 
  they 
  are 
  the 
  dark, 
  solid 
  body 
  of 
  

   the 
  sun 
  itself, 
  laid 
  bare 
  to 
  our 
  view 
  by 
  those 
  immense 
  fluctuations 
  in 
  the 
  luminous 
  regions 
  of 
  its 
  atmo- 
  

   spheie 
  to 
  which 
  it 
  appears 
  to 
  be 
  subject. 
  The 
  region 
  of 
  the 
  spots 
  is 
  confined 
  within 
  about 
  30° 
  of 
  the 
  

   sun's 
  equator, 
  and 
  from 
  their 
  motion 
  on 
  the 
  surface, 
  carefully 
  measured 
  with 
  micrometers, 
  is 
  ascer- 
  

   tained 
  the 
  position 
  of 
  the 
  equator 
  and 
  period 
  of 
  the 
  sun's 
  rotation, 
  &c. 
  — 
  (A 
  Treatise 
  on 
  Astronomy, 
  by 
  

   S;r 
  John 
  F. 
  W. 
  Hersehel, 
  pp. 
  207-211.) 
  

  

  