﻿FOGS 
  AND 
  CLOUDS 
  — 
  HUMPHREYS. 
  197 
  

  

  commonly, 
  unimportant 
  types, 
  some 
  of 
  which 
  Howard 
  probably 
  

   never 
  saw. 
  

  

  To 
  obtain 
  uniformity 
  in 
  the 
  cloud 
  reports 
  of 
  professional 
  meteor- 
  

   ologists, 
  and 
  of 
  all 
  others 
  who 
  wished 
  to 
  be 
  clearly 
  understood, 
  the 
  

   International 
  Meteorological 
  Committee 
  published 
  in 
  1910, 
  with 
  

   illustrations, 
  the 
  following 
  definitions 
  and 
  descriptions 
  of 
  cloud 
  

   forms. 
  The 
  inclosed 
  letters 
  nest 
  after 
  each 
  type 
  name 
  are 
  its 
  cus- 
  

   tomary 
  abbreviation. 
  The 
  illustrations 
  are 
  new 
  (the 
  original 
  ones 
  

   are 
  not 
  available) 
  but 
  quite 
  as 
  good 
  and 
  typical, 
  it 
  is 
  hoped, 
  as 
  

   those 
  selected 
  by 
  the 
  committee. 
  

  

  The 
  wording 
  here 
  followed 
  of 
  these 
  international 
  definitions 
  and 
  

   descriptions 
  is 
  not 
  exactly 
  that 
  of 
  the 
  original 
  publication, 
  but 
  that 
  

   given 
  in 
  the 
  second 
  edition 
  of 
  "Cloud 
  Forms," 
  1921, 
  by 
  the 
  British 
  

   Meteorological 
  Office. 
  

  

  This 
  latest 
  classification 
  of 
  the 
  clouds, 
  a 
  modification 
  and 
  exten- 
  

   sion 
  of 
  Howard's, 
  is 
  also, 
  like 
  it, 
  based 
  on 
  mere 
  appearance 
  and 
  

   not 
  on 
  anything 
  really 
  fundamental, 
  such 
  as 
  cause 
  or 
  mode 
  of 
  forma- 
  

   tion. 
  But 
  however 
  superficial 
  such 
  a 
  classification 
  may 
  be, 
  it 
  never- 
  

   theless 
  is 
  the 
  best, 
  perhaps, 
  that 
  can 
  be 
  made, 
  and 
  altogether 
  the 
  

   most 
  practical. 
  For 
  instance, 
  the 
  mode 
  of 
  origin 
  is 
  not 
  a 
  practical 
  

   basis 
  for 
  cloud 
  classification, 
  however 
  desirable, 
  because 
  several 
  types 
  

   of 
  cloud 
  are 
  formed 
  in 
  different 
  ways 
  and 
  frequently 
  one 
  can 
  not 
  

   be 
  certain 
  just 
  what 
  the 
  actual 
  way 
  really 
  was. 
  

  

  The 
  supplementary 
  remarks, 
  after 
  each 
  of 
  the 
  following 
  quoted 
  

   definitions 
  and 
  descriptions, 
  while 
  intrusive 
  in 
  position, 
  may, 
  it 
  is 
  

   hoped, 
  be 
  of 
  some 
  service 
  to 
  those 
  who 
  are 
  not 
  yet 
  cloud 
  experts. 
  

  

  INTERNATIONAL 
  DEFINITIONS 
  AND 
  DESCRIPTIONS 
  OF 
  CLOUD 
  FORMS, 
  

   AND 
  SUPPLEMENTARY 
  REMARKS. 
  

  

  1. 
  Cirrus 
  (Ci.) 
  — 
  "Detached 
  clouds 
  of 
  delicate 
  appearance, 
  -fibrous 
  

   (threadlike) 
  structure, 
  and 
  featherlike 
  form, 
  generally 
  white 
  in 
  

   color. 
  Cirrus 
  clouds 
  take 
  the 
  most 
  varied 
  shapes, 
  such 
  as 
  isolated 
  

   tufts 
  of 
  hair, 
  i. 
  e., 
  thin 
  filaments 
  on 
  a 
  blue 
  sky, 
  branched 
  filaments 
  

   in 
  feathery 
  form, 
  straight 
  or 
  curved 
  filaments 
  ending 
  in 
  tufts 
  

   (called 
  cirrus 
  uncinus), 
  and 
  others. 
  Occasionally 
  cirrus 
  clouds 
  are 
  

   arranged 
  in 
  bands, 
  which 
  traverse 
  part 
  of 
  the 
  sky 
  as 
  arcs 
  of 
  great 
  

   circles, 
  and 
  as 
  an 
  effect 
  of 
  perspective 
  appear 
  to 
  converge 
  at 
  a 
  point 
  

   on 
  the 
  horizon 
  and 
  at 
  the 
  opposite 
  point 
  also, 
  if 
  they 
  are 
  sufficiently 
  

   extended. 
  Cirro-stratus 
  and 
  cirro-cumulus 
  also 
  are 
  sometimes 
  

   similarly 
  arranged 
  in 
  long 
  bands." 
  (PL 
  2, 
  fig. 
  2; 
  pi. 
  3, 
  figs. 
  1 
  and 
  2; 
  

   and 
  pi. 
  4.) 
  

  

  An 
  interesting 
  form 
  of 
  cirrus 
  clouds 
  is 
  the 
  familiar 
  "mares' 
  tails" 
  

   (pi. 
  3, 
  fig. 
  2), 
  especially 
  when 
  a 
  considerable 
  number 
  of 
  them 
  occur 
  

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