﻿DIRECTION 
  AND 
  VELOCITY 
  OF 
  WIND. 
  

  

  33 
  

  

  the 
  wind 
  was 
  from 
  north 
  to 
  east. 
  For 
  the 
  years 
  mentioned, 
  when 
  

   there 
  were 
  bad 
  woodland 
  infestations 
  in 
  Massachusetts, 
  the 
  wind 
  

   during 
  the 
  hot 
  days 
  was 
  usually 
  southwest, 
  which 
  would 
  be 
  most 
  

   favorable 
  for 
  the 
  spread 
  of 
  the 
  insect 
  into 
  the 
  region 
  where 
  it 
  has 
  

   since 
  been 
  found 
  in 
  scattered 
  colonies. 
  

  

  The 
  relation 
  of 
  temperature 
  and 
  the 
  direction 
  and 
  velocity 
  of 
  the 
  

   wind 
  are 
  intimate, 
  as 
  shown 
  by 
  the 
  tables 
  which 
  follow. 
  

  

  It 
  has 
  been 
  stated 
  that 
  wind 
  spread 
  is 
  possible 
  when 
  the 
  tempera- 
  

   ture 
  as 
  recorded 
  by 
  the 
  Weather 
  Bureau 
  is 
  as 
  low 
  as 
  65°, 
  but 
  an 
  

   increase 
  in 
  temperature 
  makes 
  the 
  chances 
  of 
  spreading 
  greater. 
  

   Tables 
  IV 
  and 
  V 
  give 
  the 
  direction 
  of 
  the 
  wind 
  for 
  the 
  different 
  

   years, 
  at 
  the 
  Boston 
  Weather 
  Bureau 
  station 
  w 
  T 
  hen 
  the 
  temperature 
  

   was 
  65° 
  or 
  higher, 
  and 
  the 
  w 
  T 
  ind 
  velocity 
  10 
  miles 
  per 
  hour 
  or 
  more. 
  

  

  In 
  all 
  cases 
  where 
  the 
  temperature 
  is 
  70° 
  F. 
  or 
  above, 
  italic 
  letters 
  

   and 
  figures 
  are 
  used 
  in 
  the 
  columns 
  of 
  the 
  table 
  giving 
  the 
  tempera- 
  

   ture 
  and 
  the 
  direction 
  and 
  velocity 
  of 
  the 
  wind. 
  Otherwise 
  the 
  letters 
  

   and 
  figures 
  are 
  in 
  Roman. 
  

  

  Table 
  IV. 
  — 
  Temperature 
  and 
  direction 
  and 
  velocity 
  of 
  wind 
  on 
  dates 
  after 
  hatch- 
  

   ing 
  of 
  gipsy-moth 
  caterpillars, 
  1902-1911. 
  

  

  (Data 
  from 
  U. 
  S. 
  Weather 
  Bureau 
  at 
  Boston, 
  Mass.) 
  

  

  Date. 
  

  

  24 
  hours. 
  

  

  Maxi- 
  

   mum 
  

   tem- 
  

   pera- 
  

   ture. 
  

  

  Direc- 
  

   tion 
  of 
  

   wind. 
  

  

  Velocity 
  

   of 
  wind. 
  

  

  Date. 
  

  

  24 
  hours. 
  

  

  Maxi- 
  

   mum 
  

   tem- 
  

   pera- 
  

   ture. 
  

  

  Direc- 
  

   tion 
  of 
  

   wind. 
  

  

  Velocity 
  

   of 
  wind. 
  

  

  1902. 
  

   Apr. 
  21 
  

   23 
  

  

  AM 
  

  

  °F. 
  

   65 
  

   71 
  

   66 
  

   67 
  

   71 
  

   75 
  

   69 
  

   73 
  

   72 
  

   65 
  

   67 
  

   65 
  

  

  W 
  

  

  w. 
  

  

  W 
  

  

  SW 
  

  

  NW..... 
  

  

  s 
  

  

  SW 
  

  

  s 
  

  

  SW 
  

  

  W 
  

  

  N 
  

  

  W 
  

  

  Miles 
  per 
  

   hour. 
  

   12 
  

   29 
  

   26 
  

   32 
  

   18 
  

   26 
  

   19 
  

   20 
  

   26 
  

   38 
  

   19 
  

   14 
  

  

  1902. 
  

   May 
  16 
  

   17 
  

   18 
  

   21 
  

   22 
  

   23 
  

   24 
  

   25 
  

   26 
  

   27 
  

   30 
  

   31 
  

  

  AM,PM 
  

  

  AM 
  

  

  °F. 
  

  

  70 
  

  

  78 
  

  

  80 
  

   88 
  

   84 
  

   76 
  

   80 
  

   71 
  

   69 
  

   65 
  

  

  W. 
  

  

  N 
  

  

  NW..... 
  

  

  SW 
  

  

  SW 
  

  

  SW 
  

  

  SW 
  

  

  SW... 
  

  

  SW 
  

  

  5 
  

  

  w 
  

  

  SW 
  

  

  Miles 
  per 
  

   hour. 
  

   20 
  

  

  PM,AM 
  

  

  AM 
  

  

  18 
  

  

  24 
  

  

  AM,PM 
  

  

  AM 
  

  

  H 
  

  

  26 
  

  

  AM 
  

  

  16 
  

  

  28 
  

  

  29 
  

  

  May 
  5 
  

  

  7 
  

  

  8 
  

  

  9 
  

  

  AM,PM 
  

  

  AM,PM 
  

  

  AM 
  

  

  AM,PM 
  

  

  AM.PM 
  

  

  AM,PM 
  

  

  AM,PM 
  

  

  AM,PM 
  

  

  AM 
  

  

  28 
  

   19 
  

   24 
  

  

  AM,PM 
  

  

  AM,PM 
  

  

  AM 
  

  

  '4 
  

   .6 
  

   '.0 
  

  

  13 
  

  

  AM 
  

  

  AM 
  

  

  33 
  

  

  14 
  

  

  AM 
  

  

  AM 
  

  

  17 
  

  

  

  

  

  

  Note.— 
  During 
  the 
  years 
  1902, 
  1903, 
  and 
  1904 
  the 
  Boston 
  Weather 
  Bureau 
  did 
  not 
  record 
  temperati 
  

   hourly, 
  but 
  took 
  readings 
  at 
  8 
  am 
  and 
  X 
  pm 
  each 
  day. 
  AM 
  in 
  the 
  table 
  refers 
  to 
  the 
  reading 
  made 
  c 
  i 
  r 
  

   the 
  period 
  from 
  8 
  am 
  to 
  8 
  pm, 
  while 
  PM 
  covers 
  the 
  following 
  12 
  hours. 
  The 
  direction 
  of 
  the 
  wind 
  .. 
  'i 
  

   its 
  maximum 
  velocity 
  did 
  not 
  necessarily 
  occur 
  when 
  the 
  temperature 
  was 
  at 
  the 
  maximum, 
  for 
  the 
  tc 
  

   perature 
  may 
  have 
  been 
  65° 
  or 
  even 
  less 
  at 
  that 
  time. 
  

  

  Date. 
  

  

  1903. 
  

  

  Apr. 
  28 
  

   29 
  

   30 
  

  

  May 
  10 
  

   11 
  

   12 
  

   13 
  

   ll 
  

   16 
  

  

  24 
  hours. 
  

  

  AM 
  

  

  AM, 
  PM. 
  

  

  AM 
  

  

  AM 
  

  

  AM 
  

  

  AM 
  

  

  A 
  M 
  . 
  . 
  . 
  

   AM. 
  

   A 
  M 
  . 
  . 
  

  

  Temper- 
  

   ature. 
  

  

  Direction 
  

   of 
  wind. 
  

  

  Velocity 
  

   of 
  wind". 
  

  

  °F. 
  

   66 
  

   83 
  

   83 
  

  

  s 
  

  

  .vie... 
  

  

  8 
  W 
  

  

  M,l,s 
  

  

  ixr 
  hour. 
  

  

  13 
  

  

  19 
  

  

  28 
  

  

  75 
  

   69 
  

  

  S 
  

  

  S 
  

  

  19 
  

   13 
  

  

  70 
  

  

  s 
  

  

  IS 
  

  

  n 
  

  

  70 
  

   67 
  

  

  5 
  

  

  to 
  

  

  

  

  BE 
  

  

  10 
  

  

  CO 
  17 
  1 
  Hull. 
  Hit 
  H 
  3 
  

  

  