238  Conservation  and  Chemical  Engineer.  { Am-MJa°u ri9ioarm' 
Not  only  were  the  usual  experimental  difficulties  to  be  overcome 
but,  as  Prof.  Bernthsen  has  well  shown  in  his  address  before  the 
London  International  Congress  of  Applied  Chemistry  in  May  last, 
there  are  theoretical  difficulties  of  the  most  serious  kind  standing 
in  the  road  of  ready  fixation  of  atmospheric  nitrogen  and  oxygen 
in  the  form  of  nitrogen  oxides  convertible  into  nitrates.  So  it 
happened  that  the  first  large  enterprise  of  this  kind,  the  process  of 
the  Atmospheric  Products  Company,  established  at  Niagara  Falls, 
had  to  be  given  up  as  commercially  unavailable.  This  was  followed 
by  the  Birkeland  and  Eyde  process,  started  in  Norway  with  the 
cheapest  water  power  to  be  found,  and  this  is  still  in  successful 
operation.  A  few  years  later  (in  1905)  the  Schonherr  process  was 
worked  out  by  the  Badische  Anilin  and  Soda  Fabrik,  also  using 
Norwegian  water  power  and  still  later  the  Pauling  process  at  Gelsen- 
kirchen,  near  Innsbruck,  in  Tyrol.  The  Schonherr  process  seems 
to  be  the  most  successful. 
It  produces  a  40  per  cent,  nitric  acid,  calcium  nitrate,  or  calcium 
or  sodium  nitrite,  according  as  the  absorption  part  of  the  process  is 
modified.  All  of  the  processes  mentioned  require  the  cheapest  elec- 
trical energy,  which  can  only  be  developed  by  cheap  water  power, 
and  thus  far  best  developed  in  Norway.  Prof.  Bernthsen  states,  how- 
ever, that  probably  within  a  few  years  the  annual  output  of  calcium 
nitrate  or  "  air-salpetre  "  will  reach  100,000  tons.  As  this  involves 
first  the  fixation  of  atmospheric  nitrogen,  and  second  the  use  of 
"  white  coal,"  as  water  power  is  sometimes  fancifully  called,  it  is  a 
true  lesson  in  conservation  of  natural  resources,  especially  as  it  also 
enables  us  to  replace  a  rapidly  disappearing  natural  product. 
Closely  related  to  this  recently  developed  inorganic  industry  of 
air-salpetre  is  the  slightly  older  one  of  calcium  carbide  and  its  off- 
shoot the  cyanamide  or  "  nitrolime  "  industry.  With  the  production 
of  calcium  carbide  in  the  electric  furnace  in  1892  by  Willson  and  the 
publication  of  Moissan's  work  on  the  electric  furnace  in  1894,  sprang 
into  existence  a  great  industry,  as  the  acetylene  gas  lighting  made 
possible  thereby  had  great  advantages.  Isolated  lighting  plants, 
acetylene  lamps  for  automobiles  and  carriages,  luminous  buoys  and 
signals,  a  new  material  for  lampblack  manufacture,  and  other  utiliza- 
tions all  were  rapidly  developed.  The  perfecting  of  the  furnaces 
and  the  process  for  this  manufacture  of  carbide  enlisted  the  atten- 
tion of  electrical  and  chemical  engineers  and  at  the  present  time 
the  world's  production  of  calcium  carbide  is  estimated  to  be  about 
