﻿Telescopic 
  Vision. 
  809 
  

  

  for 
  the 
  circumstance 
  that 
  his 
  control 
  apparatus 
  shows 
  the 
  

   Moon 
  better 
  than 
  his 
  astronomical 
  telescope 
  can 
  show 
  Mars, 
  

   and 
  better 
  in 
  a 
  greater 
  degree 
  the 
  larger 
  the 
  objective 
  of 
  the 
  

   astronomical 
  telescope, 
  the 
  control 
  apparatus 
  being 
  very 
  much 
  

   less 
  affected 
  by 
  the 
  state 
  o£ 
  the 
  atmosphere. 
  

  

  49. 
  The 
  author 
  intended 
  to 
  have 
  given 
  here 
  an 
  account 
  

   of 
  observations 
  made 
  with 
  this 
  simple 
  apparatus 
  and 
  of 
  the 
  

   lessons 
  they 
  teach 
  the 
  astronomer, 
  but 
  finds 
  that 
  to 
  do 
  so 
  

   would 
  occupy 
  too 
  much 
  space. 
  If, 
  however, 
  any 
  reader 
  of 
  

   this 
  paper 
  is 
  willing 
  to 
  make 
  the 
  observations 
  for 
  himself, 
  

   being 
  careful 
  to 
  make 
  them 
  only 
  when 
  the 
  Moon 
  is 
  nearly 
  

   full, 
  he 
  will 
  receive 
  in 
  this 
  way 
  far 
  more 
  instruction 
  than 
  

   could 
  reach 
  him 
  by 
  merely 
  reading 
  about 
  them. 
  No 
  one 
  

   who 
  sees 
  and 
  appreciates 
  the 
  significance 
  of 
  these 
  observa- 
  

   tions 
  can 
  again 
  fall 
  into 
  the 
  error 
  of 
  supposing 
  that 
  the 
  

   astronomers 
  of 
  our 
  day 
  have 
  even 
  so 
  much 
  knowledge 
  of 
  

   what 
  exists 
  upon 
  Mars, 
  as 
  the 
  astronomers 
  of 
  old 
  before 
  the 
  

   telescope 
  was 
  invented 
  could 
  have 
  of 
  what 
  exists 
  upon 
  the 
  

   Moon. 
  In 
  fact 
  they 
  have 
  not 
  nearly 
  so 
  much. 
  It 
  is 
  easy 
  

   for 
  us 
  now 
  when 
  we 
  look 
  at 
  the 
  Moon 
  with 
  the 
  naked 
  eye 
  

   to 
  read 
  into 
  what 
  we 
  then 
  see, 
  some 
  of 
  the 
  details 
  with 
  which 
  

   the 
  telescope 
  has 
  made 
  us 
  familiar 
  ; 
  but 
  those 
  old 
  astronomers 
  

   had 
  no 
  such 
  help, 
  nor 
  has 
  any 
  man 
  that 
  kind 
  of 
  help 
  noio 
  in 
  

   reference 
  to 
  Mars, 
  

  

  50. 
  A 
  distinct 
  advance 
  would 
  be 
  made 
  if 
  scientific 
  men 
  

   would 
  desist 
  from 
  talking 
  about 
  what 
  can 
  be 
  seen 
  " 
  upon 
  

   Mars/' 
  Nobody 
  has 
  as 
  yet 
  seen 
  what 
  is 
  on 
  Mars 
  nor 
  any- 
  

   thing 
  like 
  what 
  is 
  upon 
  Mars. 
  What 
  the 
  astronomer 
  has 
  

   had 
  presented 
  to 
  hirn 
  has 
  really 
  been 
  an 
  eidolon, 
  that 
  is 
  a 
  

   model 
  such 
  as 
  a 
  sculptor 
  could 
  make 
  and 
  which 
  would 
  

   present 
  to 
  the 
  sculptor's 
  eye 
  precisely 
  the 
  same 
  appearance 
  as 
  

   the 
  telescope 
  presents 
  to 
  the 
  astronomer. 
  It 
  is 
  not 
  upon, 
  what 
  

   is 
  on 
  Mars 
  that 
  the 
  astronomer 
  is 
  enabled 
  by 
  his 
  telescope 
  

   to 
  look. 
  He 
  sees 
  whatever 
  finds 
  a 
  legitimate 
  place 
  upon 
  

   this 
  model 
  and 
  nothing 
  more 
  ; 
  and 
  our 
  control 
  experiments 
  

   show 
  that 
  what 
  he 
  sees 
  would 
  amount 
  to 
  being 
  an 
  effective 
  

   disguise 
  thrown 
  over 
  what 
  is 
  really 
  upon 
  the 
  planet. 
  How 
  

   utterly 
  unlike 
  it 
  must 
  be 
  to 
  what 
  is 
  really 
  upon 
  the 
  planet 
  

   is 
  forced 
  upon 
  his 
  attention 
  when 
  making 
  the 
  control 
  ex- 
  

   periments, 
  if 
  he 
  is 
  acquainted 
  with 
  the 
  details 
  which 
  an 
  

   adequate 
  telescope 
  reveals 
  upon 
  the 
  Moon, 
  and 
  compares 
  these 
  

   with 
  what 
  is 
  substituted 
  for 
  them 
  when 
  a 
  full 
  moon 
  is 
  viewed 
  

   through 
  telescopes 
  as 
  inefficient 
  upon 
  the 
  Moon 
  as 
  our 
  best 
  

   astronomical 
  telescopes 
  are 
  upon 
  Mars. 
  

  

  51. 
  Nor, 
  unfortunately, 
  do 
  we 
  seem 
  entitled 
  to 
  expect 
  

   much 
  better 
  results 
  from 
  employing 
  very 
  much 
  larger 
  tele- 
  

   scopes 
  than 
  those 
  hitherto 
  brought 
  to 
  bear. 
  Will 
  the 
  optical 
  

  

  