306 AMMONIA AND NITRIC ACID. 



120 millions of inhabitants. Now if we suppose that 

 upon these lands for centuries to come 6 million cwt. 

 ( = 300,000 tons) of Peruvian guano, containing 360,- 

 000 cwt. of ammonia, were annually applied, and that 

 it was possible, with the means at present at our dis- 

 posal, by 5 Ibs. of ammonia to raise 65 Ibs. additional of 

 wheat, or its equivalent value, then the increased crop 

 of corn would just reach so far as to give each individ- 

 ual in the community 2 Ibs. of corn a day for two days 

 in the year. 



If we assume 2 Ibs. of corn or its equivalent to be 

 the average amount of nutriment required by an indi- 

 vidual, this makes 730 Ibs. annually. According to 

 the supposition made above, 36 million pounds of am- 

 monia would produce thirteen times as much = 468 

 million pounds of corn or its equivalent, whereby 641,- 



000 individuals could be nourished for a year. 

 Supposing the population of England and Wales to 



increase only 1 per cent, annually, this makes 200,000 

 individuals in one year, and 600,000 in three years. 

 Now the cereals hypothetically raised by help of the 

 ammonia in 6 million cwt. of guano imported from 

 abroad, would suffice but very few years to support the 

 increased population of England and Wales. 



And what would be the state of things six or nine 

 years afterwards in England or Europe, if we were 

 actually dependent upon a foreign importation of am- 

 monia, for the support of the increasing population? 

 Could we import 12 million cwt. of guano in six years, 

 or 18 million in nine years ? 



We know most positively, that in a few years the 

 source of ammonia in guano will be exhausted ; that 

 we have no prospect of discovering a new and richer 

 source ; that the annual increase of population, not only 

 in England but in all European countries, is more than 



1 per cent. ; and, finally, that in proportion to the in- 

 crease in the population in the United States, Hungary, 

 &c., a corresponding diminution must follow in the ex- 

 portation of corn from those countries. From these 

 considerations the hope of augmenting the crops of a 



