﻿592 
  DR 
  GEORGE 
  WILSON 
  ON 
  NITRIC 
  ACID 
  

  

  should 
  not 
  be 
  formed 
  in 
  very 
  large 
  quantity 
  ; 
  while 
  ammonia 
  forms 
  less 
  than 
  

   one-1 
  0,000th 
  of 
  the 
  air, 
  perhaps 
  much 
  less. 
  Nitric 
  acid 
  is 
  only 
  found 
  in 
  springs 
  

   where 
  decaying 
  organic 
  matter 
  is 
  near 
  them, 
  as 
  in 
  towns, 
  and 
  is 
  formed 
  from 
  the 
  

   ammonia 
  produced 
  in 
  their 
  decay, 
  by 
  the 
  same 
  process 
  as 
  in 
  nitrification. 
  Besides, 
  

   while 
  we 
  have 
  no 
  proof 
  that 
  plants 
  decompose 
  nitric 
  acid, 
  which 
  it 
  is 
  certainly 
  

   possible 
  they 
  may 
  do, 
  we 
  know 
  that 
  many 
  plants, 
  such 
  as 
  tobacco 
  and 
  sunflower, 
  

   actually 
  produce 
  nitric 
  acid, 
  or, 
  at 
  least, 
  do 
  not 
  destroy 
  that 
  which 
  enters 
  them."* 
  

  

  Thus 
  far 
  Dr 
  Gregory. 
  I 
  at 
  once 
  concede 
  to 
  him 
  that 
  plants 
  are 
  largely 
  in- 
  

   debted 
  to 
  ammonia 
  for 
  the 
  nitrogen 
  found 
  in 
  them 
  ; 
  and 
  in 
  support 
  of 
  the 
  belief 
  

   that 
  they 
  are 
  also 
  indebted 
  to 
  nitric 
  acid 
  for 
  their 
  nitrogen, 
  I 
  adduce 
  the 
  follow- 
  

   ing 
  proofs. 
  

  

  Firstly, 
  The 
  production 
  of 
  nitric 
  acid 
  in 
  the 
  atmosphere 
  during 
  thunder- 
  

   storms, 
  is 
  a 
  certain, 
  not 
  a 
  questionable 
  fact 
  ; 
  and 
  the 
  scale 
  on 
  which 
  it 
  is 
  pro- 
  

   duced 
  is 
  such 
  as 
  to 
  necessitate 
  its 
  recognition 
  as 
  a 
  portion 
  of 
  the 
  azotised 
  food 
  of 
  

   plants. 
  That 
  this 
  should 
  have 
  been 
  questioned 
  is 
  perhaps 
  not 
  strange, 
  for 
  the 
  

   newly-discovered 
  truth 
  that 
  ammonia 
  is 
  generally 
  present 
  in 
  the 
  air, 
  could 
  scarcely 
  

   fail 
  to 
  throw 
  into 
  temporary 
  oblivion 
  the 
  equally 
  important 
  truth 
  that 
  nitric 
  acid 
  

   is 
  generally 
  present 
  there 
  also. 
  The 
  name 
  of 
  the 
  great 
  living 
  chemist 
  Liebig 
  

   is 
  identified 
  with 
  the 
  one 
  discovery, 
  and 
  the 
  name 
  of 
  the 
  great 
  dead 
  chemist 
  

   Cavendish 
  with 
  the 
  other 
  ; 
  and 
  we 
  must 
  not 
  grudge 
  that 
  greater 
  interest 
  should 
  

   be 
  felt 
  by 
  most 
  in 
  the 
  doings 
  of 
  the 
  living 
  philosopher. 
  But 
  assuredly 
  it 
  is 
  not 
  

   necessary 
  to 
  set 
  the 
  two 
  truths 
  against 
  each 
  other, 
  as 
  if 
  they 
  were 
  mutually 
  in- 
  

   compatible, 
  or 
  in 
  any 
  respect 
  contradictory. 
  On 
  the 
  other 
  hand, 
  I 
  believe 
  that 
  

   they 
  are 
  complementary, 
  and 
  form 
  an 
  essential 
  and 
  manifest 
  part 
  of 
  that 
  harmo- 
  

   nious 
  adjustment 
  which 
  we 
  everywhere 
  perceive 
  guarding 
  plants 
  and 
  animals 
  

   against 
  imperfect 
  nourishment 
  or 
  decay. 
  

  

  In 
  the 
  year 
  1781, 
  Cavendish 
  addressed 
  himself 
  to 
  the 
  task 
  of 
  answering 
  this 
  

   question, 
  among 
  others, 
  " 
  Why 
  does 
  the 
  passage 
  of 
  an 
  electric 
  spark 
  through 
  a 
  

   confined 
  portion 
  of 
  air, 
  cause 
  a 
  diminution 
  in 
  its 
  volume 
  ?"f 
  ' 
  He 
  did 
  not 
  give 
  a 
  

   categorical 
  reply 
  to 
  this 
  question 
  till 
  1 
  785, 
  when 
  he 
  published 
  his 
  discovery 
  that 
  

   a 
  mixture 
  of 
  two 
  measures 
  of 
  nitrogen 
  and 
  five 
  measures 
  of 
  oxygen 
  can 
  be 
  entirely 
  

   converted 
  into 
  nitric 
  acid, 
  by 
  sending 
  a 
  succession 
  of 
  electric 
  sparks 
  through 
  it. 
  J 
  

   He 
  had 
  observed 
  the 
  fact, 
  however, 
  in 
  1781, 
  in 
  the 
  course 
  of 
  the 
  famous 
  experi- 
  

   ments 
  which 
  led 
  to 
  the 
  discovery 
  of 
  the 
  composition 
  of 
  water, 
  — 
  a 
  truth 
  to 
  which 
  

   I 
  refer, 
  because 
  an 
  impression 
  is 
  prevalent, 
  that 
  the 
  conversion 
  of 
  a 
  mixture 
  of 
  

   nitrogen 
  and 
  oxygen 
  into 
  nitric 
  acid 
  by 
  the 
  electric 
  spark, 
  can 
  only 
  be 
  effected 
  

   with 
  great 
  difficulty, 
  whereas 
  the 
  undesired 
  and 
  unintended 
  production 
  of 
  this 
  

   acid, 
  in 
  trials 
  instituted 
  with 
  a 
  totally 
  different 
  object 
  in 
  view, 
  was 
  the 
  chief 
  

  

  * 
  Gregory's 
  Organic 
  Chemistry. 
  Third 
  Edition, 
  p. 
  466. 
  

  

  f 
  Phil. 
  Trams., 
  1784, 
  p. 
  119. 
  + 
  Ibid, 
  1785, 
  p. 
  372. 
  

  

  