﻿1 
  2U 
  Tramaotioiis, 
  — 
  Miscellaneouii, 
  

  

  after 
  collision 
  any 
  portion 
  will 
  acquire 
  much 
  greater 
  energy 
  than 
  before, 
  we 
  

   may 
  reasonably 
  assume 
  that 
  no 
  part 
  will 
  acquire 
  four 
  times 
  the 
  energy 
  of 
  

   motion, 
  and 
  be 
  thrown 
  off 
  into 
  space. 
  On 
  the 
  other 
  hand, 
  if 
  two 
  bodies 
  

   come 
  into 
  partial 
  collision, 
  a 
  piece 
  of 
  each 
  would 
  coalesce, 
  and 
  the 
  rest 
  

   would 
  pass 
  on 
  into 
  space. 
  If 
  the 
  motion 
  be 
  entirely 
  destroyed, 
  the 
  temperature 
  

   developed 
  by 
  coalescence 
  will 
  be 
  the 
  same, 
  no 
  matter 
  what 
  proportion 
  be 
  

   struck 
  off; 
  whilst, 
  if 
  the 
  pieces 
  struck 
  off 
  be 
  very 
  small, 
  the 
  coalesced 
  mass 
  

   will 
  have 
  but 
  little 
  attractive 
  power 
  to 
  keep 
  the 
  body 
  together, 
  and 
  hence 
  

   the 
  velocity 
  of 
  each 
  particle 
  may 
  be 
  great 
  enough 
  to 
  project 
  the 
  whole 
  into 
  

   space 
  ; 
  whereas 
  we 
  have 
  seen, 
  in 
  the 
  case 
  of 
  complete 
  coalescence, 
  none 
  

   would 
  be 
  able 
  to 
  be 
  thus 
  projected. 
  This 
  is 
  a 
  most 
  important 
  distinction 
  

   between 
  partial 
  and 
  complete 
  collision. 
  

  

  Influence 
  of 
  Chemical 
  Composition. 
  

   If 
  two 
  bodies, 
  each 
  a 
  mixture 
  of 
  chemical 
  elements, 
  meet 
  and 
  destroy 
  

   their 
  motion 
  of 
  translation, 
  then 
  a 
  molecular 
  motion 
  of 
  identically 
  the 
  

   same 
  energy 
  must 
  be 
  developed 
  (a 
  small 
  part 
  will 
  be 
  converted 
  into 
  some 
  

   form 
  of 
  potential 
  energy, 
  but 
  this 
  we 
  will 
  disregard). 
  If 
  a 
  mass 
  of 
  small 
  

   bodies 
  have 
  the 
  same 
  energy 
  as 
  an 
  equal 
  single 
  mass, 
  the 
  velocity 
  is 
  also 
  

   equal. 
  Whence 
  we 
  must 
  also 
  assume 
  that 
  the 
  velocity 
  of 
  the 
  molecules, 
  

   no 
  matter 
  what 
  may 
  be 
  their 
  respective 
  weights, 
  is 
  not 
  greater 
  than 
  the 
  

   velocity 
  of 
  the 
  whole 
  body 
  was 
  before 
  impact. 
  Therefore, 
  from 
  what 
  has 
  

   been 
  stated, 
  in 
  direct 
  impact 
  no 
  particle 
  will 
  have 
  sufficient 
  velocity 
  to 
  leave 
  

   the 
  mass 
  imm-ediatehj 
  after 
  impact. 
  But 
  different 
  elements 
  having 
  the 
  same 
  

   velocity 
  are 
  at 
  different 
  temperat;ires, 
  inversely 
  proportional 
  to 
  their 
  mole- 
  

   cular 
  weight 
  ; 
  the 
  heavy 
  atoms 
  are 
  therefore 
  very 
  much 
  hotter 
  than 
  the 
  

   light 
  ones. 
  AVe 
  know 
  by 
  the 
  laws 
  of 
  heat 
  that 
  these 
  unequal 
  temperatures 
  

   will 
  tend 
  to 
  equality 
  ; 
  but 
  it 
  is 
  worth 
  while 
  looking 
  at 
  this 
  a 
  little 
  in 
  detail. 
  

   Let 
  us 
  suppose 
  a 
  hydrogen 
  and 
  a 
  mercury 
  particle 
  to 
  meet. 
  The 
  mercury 
  

   is 
  one 
  hundred 
  times 
  as 
  heavy 
  as 
  hydrogen, 
  but 
  the 
  velocity 
  of 
  both 
  is 
  the 
  

   same. 
  The 
  collision 
  cannot 
  produce 
  heat, 
  as 
  it 
  is 
  heat 
  motion 
  already. 
  

   The 
  principle 
  of 
  energy 
  at 
  once 
  tells 
  us 
  that 
  the 
  mercury 
  wiU 
  lose 
  a 
  part 
  

   of 
  its 
  velocity, 
  and 
  the 
  velocity 
  of 
  the 
  hydrogen 
  will 
  be 
  increased. 
  Let 
  this 
  

   happen 
  many 
  times, 
  and 
  the 
  temperature 
  will 
  become 
  equal 
  ; 
  in 
  other 
  

   words, 
  the 
  hydrogen 
  will 
  be 
  moving 
  ten 
  times 
  as 
  fast 
  as 
  the 
  mercury. 
  Let 
  

   both 
  of 
  these 
  particles 
  come 
  to 
  the 
  surface 
  of 
  the 
  body 
  ; 
  theii- 
  molecular 
  

   motion 
  will 
  cause 
  them 
  to 
  leave 
  it 
  ; 
  the 
  hydrogen 
  will 
  probably 
  have 
  velocity 
  

   sufficient 
  to 
  carry 
  it 
  away 
  from 
  effective 
  attraction, 
  which 
  is 
  impossible 
  

   with 
  the 
  mercury, 
  as 
  initially 
  its 
  velocity 
  was 
  insufficient, 
  and 
  now 
  it 
  is 
  less 
  

   than 
  before. 
  Thus 
  we 
  see 
  that 
  at 
  the 
  surface 
  of 
  a 
  mixed 
  gaseous 
  atmo- 
  

   sphere 
  there 
  is 
  a 
  tendency 
  the 
  opposite 
  to 
  that 
  of 
  the 
  diffusion 
  of 
  gases 
  ; 
  

   probably 
  the 
  hydrogen 
  and 
  lighter 
  atomic 
  weight 
  elements 
  will 
  be 
  on 
  the 
  out- 
  

  

  