236 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1909. 
tained 359,560 tons of ammonium sulphate, all of which if desired 
could have been converted into nitric acid for use in the manufacture 
of saltpeter or of any desired variety of explosive. 
From this account of recent chemical progress it is evident that 
it is possible to conduct a prolonged war without robbing the soil 
on which the people depend for food of its fertility, and further, 
that, notwithstanding the enormous and constantly increasing de- 
mand for nitrogen compounds in agriculture and manufacture, this 
country has reached a potential degree of independence, as regards 
its supply of nitrogen compounds for military uses, such as it never 
before enjoyed, so that it needs hereafter to consider foreign sources 
of supply only from the economic standpoint. However, I desire to 
say regarding the plants for the fixation of nitrogen what I have 
repeatedly advised regarding plants for the manufacture of explo- 
sives, viz, that it is a wise policy for our Government to foster, and 
In a measure supervise, these manufacturing operations, and to look 
_to it that plants for these purposes are so strategically located 
throughout the country as to be reasonably well protected from 
attack, so that they may serve the military establishment in case of 
foreign invasion from any quarter or of internal uprisings in any 
locality. 
