﻿182 
  ANNUAL 
  REPORT 
  SMITHSONIAN 
  INSTITUTION, 
  1922. 
  

  

  large 
  calories, 
  so 
  that 
  six 
  hours 
  of 
  insolation 
  per 
  square 
  meter 
  rep- 
  

   resents 
  a 
  heat 
  equivalent 
  of 
  0.675 
  kilogram 
  of 
  coal, 
  and 
  on 
  an 
  acre 
  

   16.41 
  tons 
  of 
  coal. 
  This 
  for 
  90 
  days 
  of 
  insolation 
  would 
  equal 
  

   1,476.63 
  tons. 
  

  

  In 
  order 
  to 
  gain 
  some 
  idea 
  of 
  the 
  degree 
  of 
  efficiency 
  of 
  the 
  photo- 
  

   synthetic 
  process 
  in 
  utilizing 
  solar 
  radiation 
  as 
  expressed 
  in 
  the 
  yield 
  

   of 
  agricultural 
  products, 
  the 
  heat 
  value 
  of 
  a 
  cereal 
  crop 
  can 
  serve 
  as 
  

   a 
  comparison. 
  Taking 
  the 
  very 
  large 
  yield 
  of 
  50 
  bushels, 
  or 
  17.619 
  

   hectoliters 
  of 
  wheat 
  per 
  acre, 
  and 
  considering 
  this 
  as 
  entirely 
  starch, 
  

   we 
  get 
  an 
  energy 
  equivalent 
  of 
  0.623 
  ton 
  of 
  coal. 
  This 
  last 
  figure 
  of 
  

   about 
  two-thirds 
  of 
  a 
  ton 
  of 
  coal 
  is 
  to 
  be 
  compared 
  to 
  the 
  1,476 
  tons, 
  

   representing 
  the 
  total 
  solar 
  radiation 
  during 
  a 
  period 
  of 
  90 
  days, 
  

   approximately 
  a 
  growing 
  season. 
  

  

  This, 
  then, 
  is 
  the 
  amount 
  of 
  solar 
  energy 
  received 
  at 
  the 
  surface 
  of 
  

   the 
  earth 
  and 
  in 
  a 
  practical 
  sense 
  the 
  amount 
  of 
  this 
  energy 
  that 
  is 
  

   stored 
  by 
  means 
  of 
  agriculture. 
  It 
  is 
  a 
  very 
  striking 
  fact 
  that 
  the 
  

   processes 
  of 
  organic 
  nature 
  are 
  exceedingly 
  inefficient 
  and 
  wasteful. 
  

   This, 
  of 
  course, 
  is 
  so 
  of 
  necessity. 
  Faced 
  with 
  the 
  uncertainties 
  of 
  

   environmental 
  and 
  climatic 
  conditions, 
  only 
  such 
  processes 
  as 
  are 
  

   allowed 
  a 
  wide 
  margin 
  of 
  safety 
  are 
  assured 
  the 
  living 
  organism 
  of 
  

   survival. 
  These 
  figures 
  also 
  indicate 
  that 
  agriculture, 
  as 
  the 
  only 
  

   photochemical 
  industry, 
  is 
  utilizing 
  but 
  a 
  very 
  small 
  portion 
  of 
  the 
  

   available 
  energy. 
  

  

  In 
  discussing 
  the 
  possibility 
  of 
  preparing 
  liquid 
  fuel 
  from 
  grain, 
  

   Boyd 
  3 
  makes 
  the 
  following 
  statements 
  : 
  

  

  The 
  large 
  amount 
  of 
  motor 
  fuel 
  required 
  seems 
  to 
  exclude 
  the 
  possibility 
  of 
  

   preparing 
  any 
  considerable 
  percentage 
  of 
  the 
  necessary 
  amount 
  from 
  foodstuffs. 
  

   In 
  illustration 
  of 
  this 
  statement 
  the 
  following 
  figures 
  are 
  of 
  interest 
  : 
  

  

  Bushels. 
  

  

  Average 
  annual 
  United 
  States 
  production 
  of 
  corn, 
  1913-1919 
  2, 
  740, 
  000, 
  000 
  

  

  Average 
  annual 
  acreage 
  in 
  corn, 
  1913-1919 
  160, 
  000, 
  000 
  

  

  Alcohol 
  from 
  the 
  corn 
  at 
  2.75 
  gallons 
  per 
  bushel 
  7, 
  500, 
  000, 
  000 
  

  

  The 
  heating 
  value 
  of 
  this 
  amount 
  of 
  alcohol 
  is 
  about 
  equal 
  to 
  that 
  of 
  

   5,000,000,000 
  gallons 
  of 
  gasoline. 
  The 
  production 
  of 
  gasoline 
  in 
  the 
  United 
  

   States 
  during 
  1920 
  was 
  very 
  close 
  to 
  this 
  amount, 
  about 
  4,900,000,000 
  gallons. 
  

   The 
  average 
  acreage 
  in 
  corn 
  as 
  given 
  above 
  is 
  equal 
  to 
  166,000 
  square 
  miles, 
  

   which 
  is 
  more 
  than 
  four 
  times 
  the 
  total 
  area 
  of 
  Ohio. 
  In 
  view 
  of 
  the 
  fact 
  that 
  

   the 
  possible 
  alcohol 
  production 
  from 
  corn 
  represents 
  close 
  to 
  60 
  per 
  cent 
  of 
  the 
  

   total 
  possible 
  amount 
  of 
  alcohol 
  that 
  could 
  be 
  prepared 
  from 
  all 
  of 
  the 
  starch 
  

   and 
  sugar 
  containing 
  foodstuffs 
  produced 
  in 
  the 
  United 
  States, 
  and 
  that 
  such 
  a 
  

   large 
  acreage 
  is 
  required 
  for 
  its 
  production, 
  the 
  possibility 
  of 
  a 
  sufficiently 
  large 
  

   increase 
  in 
  production 
  of 
  such 
  materials 
  to 
  be 
  diverted 
  to 
  the 
  manufacture 
  of 
  

   motor 
  fuel 
  seems 
  very 
  unlikely. 
  At 
  any 
  rate, 
  if 
  large 
  quantities 
  of 
  motor 
  fuel 
  

   are 
  to 
  be 
  prepared 
  from 
  vegetation, 
  another 
  material, 
  if 
  not 
  instead 
  of 
  food- 
  

   stuffs 
  at 
  least 
  in 
  addition 
  to 
  foodstuffs, 
  must 
  be 
  relied 
  upon 
  as 
  a 
  source. 
  

  

  ■ 
  " 
  Motor 
  Fuel 
  from 
  Vegetation," 
  Journal 
  of 
  Industrial 
  and 
  Engineering 
  Chemistry, 
  13 
  

   (1922), 
  836. 
  

  

  