﻿376 
  ON 
  THE 
  CAUSES 
  OF 
  

  

  The 
  time 
  of 
  their 
  falling, 
  and 
  consequently 
  the 
  direction 
  agreeably 
  

   to 
  the 
  observations 
  of 
  professor 
  Bache, 
  appear 
  to 
  have 
  been 
  deter- 
  

   mined 
  not 
  only 
  by 
  the 
  extent 
  of 
  the 
  force 
  to 
  which 
  they 
  were 
  exposed, 
  

   but 
  likewise 
  by 
  the 
  strength 
  of 
  their 
  roots, 
  or 
  the 
  degree 
  of 
  protection 
  

   afforded 
  them 
  by 
  other 
  bodies, 
  trees 
  or 
  houses 
  for 
  instance. 
  On 
  these 
  

   accounts, 
  neighbouring 
  trees, 
  falling 
  at 
  different 
  times, 
  had 
  different 
  

   bearings 
  ; 
  but 
  that 
  they 
  all 
  fell 
  towards 
  the 
  point 
  occupied 
  by 
  the 
  axis 
  

   of 
  the 
  tornado 
  at 
  the 
  time 
  of 
  their 
  overthrow, 
  appears 
  to 
  be 
  consistent 
  

   with 
  the 
  facts. 
  In 
  one 
  instance, 
  both 
  professor 
  Bache 
  and 
  Mr 
  Espy 
  

   observed 
  that 
  the 
  post 
  of 
  a 
  frame 
  building, 
  being 
  dislodged 
  from 
  the 
  

   stone 
  on 
  which 
  it 
  rested, 
  was 
  first 
  moved 
  towards 
  the 
  path 
  of 
  the 
  tor- 
  

   nado 
  in 
  one 
  direction 
  about 
  eighteen 
  inches, 
  marking 
  its 
  course 
  by 
  a 
  

   furrow 
  in 
  the 
  ground, 
  and 
  afterwards 
  moved 
  in 
  another 
  direction, 
  nearly 
  

   at 
  right 
  angles 
  to 
  the 
  former, 
  leaving 
  a 
  similar 
  indication 
  of 
  the 
  course 
  

   in 
  which 
  it 
  had 
  moved. 
  Intermediately 
  between 
  the 
  time 
  when 
  the 
  

   tornado 
  bore 
  in 
  those 
  directions, 
  the 
  frame 
  was 
  protected 
  bya 
  house. 
  

  

  While 
  the 
  phenomena 
  above 
  described 
  sufficiently 
  indicate 
  the 
  ex- 
  

   istence 
  of 
  a 
  horizontal 
  conflux 
  of 
  the 
  air, 
  that 
  of 
  a 
  vertical 
  force 
  was 
  

   demonstrated 
  by 
  the 
  transportation 
  of 
  the 
  debris 
  of 
  the 
  houses 
  and 
  

   trees, 
  as 
  well 
  as 
  lighter 
  bodies, 
  to 
  a 
  great 
  distance. 
  A 
  lady's 
  reticule 
  

   was 
  carried 
  seven 
  miles 
  from 
  New 
  Brunswick, 
  and 
  a 
  letter 
  twenty 
  

   miles. 
  The 
  piece 
  of 
  timber, 
  technically 
  called 
  the 
  plate, 
  on 
  which 
  the 
  

   rafters 
  of 
  the 
  roof 
  of 
  a 
  meetinghouse 
  in 
  New 
  Brunswick 
  rested, 
  was 
  

   carried 
  nearly 
  a 
  quarter 
  of 
  a 
  mile, 
  and 
  lodged 
  in 
  some 
  trees 
  beyond 
  the 
  

   Raritan. 
  The 
  fields, 
  on 
  the 
  other 
  side 
  of 
  that 
  river, 
  were 
  strewed 
  with 
  

   shingles 
  torn 
  from 
  the 
  houses 
  in 
  the 
  town. 
  

  

  After 
  maturely 
  considering 
  all 
  the 
  facts, 
  I 
  am 
  led 
  to 
  suggest 
  that 
  a 
  

   tornado 
  is 
  the 
  effect 
  of 
  an 
  electrified 
  current 
  of 
  air, 
  superseding 
  the 
  

   more, 
  usual 
  means 
  of 
  discharge 
  between 
  the 
  earth 
  and 
  clouds 
  in 
  those 
  

   sparks 
  or 
  flashes 
  which 
  are 
  called 
  lightning. 
  I 
  conceive 
  that 
  the 
  inevi- 
  

   table 
  effect 
  of 
  such 
  a 
  current 
  would 
  be 
  to 
  counteract 
  within 
  its 
  sphere 
  

   the 
  pressure 
  of 
  the 
  atmosphere, 
  and 
  thus 
  enable 
  this 
  fluid, 
  in 
  obedience 
  

   to 
  its 
  elasticity, 
  to 
  rush 
  into 
  the 
  rarer 
  medium 
  above. 
  

  

  It 
  will, 
  I 
  believe, 
  be 
  admitted, 
  that 
  whenever 
  there 
  is 
  sufficient 
  

   electricity 
  generated 
  to 
  afford 
  a 
  succession 
  of 
  sparks, 
  the 
  quantity 
  must 
  

   be 
  sufficient, 
  under 
  favourable 
  circumstances, 
  to 
  be 
  productive 
  of 
  an 
  

  

  