Aj;nu°aury  isST*  }  Oxidation  of  Nitrogen.  33 
-    -  +  +-f 
In  the  place  of  O  we  might  place  02,  02,  O,  O,  03,  Oe.  and  O.  We 
thus  have  56  possible  chemical-  reactions  to  represent  the  fixation  of 
nitrogen.   No  doubt,  only  a  few  of  these  reactions  actually  take  place, 
though  all  are  possible,  provided  all  these  kinds  of  ions  exist  where 
the  oxides  of  nitrogen  are  being  formed. 
The  comparative  probability  of  some  of  these  reactions  is  very 
small,  especially  when  more  than  two  products  take  part  in  the  reac- 
tion. Since  the  oxides  of  nitrogen  are  apparently  not  removed  from 
the  gases  by  the  electric  field,  it  is  probable  that  the  oxides  of  nitrogen 
centres  are  not  charged.  Hence  it  follows  that  reactions  which  in- 
volve the  presence  of  an  electron  are  improbable.  The  apparent  fact 
that  the  reaction  is  "  electrical  "  would  indicate  that  the  reactions 
N2  +  O2  and  N  +  O  are  not  probable.  The  latter  is  in  accord  with 
the  view  that  active  nitrogen  consists  of  N  and  that  N  does  not  take 
any  active  part  in  the  formation  of  oxides  of  nitrogen. 
It  seems  quite  probable,  therefore,  that  the  main  reaction  that 
results  in  the  formation  of  oxides  of  nitrogen  is 
+ 
N2  +  O2  +  43,000  calories  =  2NO 
This  type  of  ionization  is  produced  by  cathode  rays  or  rapidly- 
moving  electrons,  according  to  Thomson  and  others,  and  accordingly 
this  equation  would  indicate  that  the  oxidization  of  nitrogen  is  in- 
directly due  to  cathode  rays.  It  may  be  for  this  reason  that  thermi- 
onic electron  radiations  may  play  an  important  role  in  the  formation 
of  oxides  of  nitrogen  in  the  various  arc  processes.  In  contrast  to  the 
above  reaction  is  the  reaction  resulting  in  the  formation  of  ozone. 
Ozone  must  necessarily  be  formed  under  conditions  where  some  02 
is  dissociated. 
The  above  reaction  may  be  only  one  of  several  reactions,  and 
under  different  conditions  of  pressure  ^nd  temperature  these  reac- 
tions may  be  of  relatively  quite  different  degrees  of  importance. 
Efficiency  of  the  Nitrogen-fixing  Process. 
We  can  get  some  idea  of  the  inefficiency  of  the  present  methods 
of  oxidizing  nitrogen  when  we  consider  that  when  gramme  molecular 
weights  of  the  gases  are  used  one  has : 
N2  -f-  02  -f-  43,000  calories  =  2NO 
approximately.  The  amount  of  energy  used  in  this  reaction  is  there- 
fore about  1.7  (io)12  ergs  for  about  126  Gms.  of  nitric  acid.  Assum- 
