1920] SOILS — FERTILIZERS. 219 



posals relevant thereto which may be submitted; (2) to examine Into the 

 supply of the raw materials required — e. g., pure nitrogen and hydrogen — 

 and into the utilization of the by-products obtained; (3) to consider what 

 steps can witli advantage be taken to conserve and increase the national re- 

 sources in nitrogen-bearing compounds and to limit their wastage; and (4) to 

 carry out the experimental work necessary to arrive at definite conclusions 

 as to the practicability and efficiency of such processes as may appear to the 

 committee to be of value. The evidence dealing with the economics of the 

 established synthetic and nonsynthetic processes is summarized in the following 

 salient points and conclusions: 



A metric ton of nitrogen gas can be separated from the air by modern lique- 

 faction processes for less than fl. The market price of a metric ton of com- 

 bined nitrogen in the United Kingdom prior to the war varied from £66 to 

 £67 (in the forms of ammonium sulphate and Chile nitrate, respectively). 

 The synthetic processes can produce a metric ton of combined nitrogen at a 

 cost, from the factory, of from £20 to £30, whereas the lowest recorded mar- 

 ket price in the United Kingdom for a metric ton of combined nitrogen (as 

 ammonium sulphate) was £35.8 in 1897. The sj'nthetlc processes can pro- 

 duce a metric ton of concentrated (93 to 96 per cent) nitric acid for about 

 half the cost by the Chile nitrate retort process, and a metric ton of combined 

 nitrogen ready for the fertilizer market, as cyanamid or ammonium sulphate 

 at a cost at the factory of about or even less than one-half the prewar mar- 

 ket price of combined nitrogen in the United Kingdom. 



The synthetic processes, with the exception of the arc process under favor- 

 able conditions as regards cheap water power, are not regarded as in a posi- 

 tion to produce nitrate fertilizers at a sufficiently low cost to face the pos- 

 sible competition of Chile nitrate. This position may, however, be altered by 

 the development of more economical methods of recovering oxids of nitrogen 

 in the form of nitrate salts. The capital expenditure for Installing the syn- 

 thetic processes is not excessive, being somewhat less than or on a parity with 

 the prewar market value of the annual production, except In the case of the 

 arc process, for which the outlay is nearly twice the market value of the an- 

 nual production. The facility with which oxygen and the rare gases of the 

 atmosphere can be obtained as by-products in the manufacture of cyanamid 

 and synthetic ammonia is an asset In favor of these processes for British 

 conditions, on account of the fact that several important industries would de- 

 rive a substantial advantage from the marketing of additional supplies of 

 these gases at reasonable prices. The relative merits of the processes them- 

 selves, however, would probably not be affected by the prices obtainable for 

 the by-products. 



A number of appendixes are included on different processes for nitrogen 

 recovery. The section on the recovery of nitrogen from peat presents the con- 

 clusion that it is doubtful whether the utilization of peat on a large scale 

 for nitrogen recovery and power production is likely to result in the production 

 of ammonium sulpliate at the low costs sometimes put forward, or in the at- 

 tainment of the high profits that have often been estimated. 



Tlie section on the recovery of nitrogen from sewage presents the conclusion 

 that " from a consideration of the general conditions of modern sanitation, and 

 from the evidence previously discussed, It Is apparent that a very large pro- 

 portion of the combined nitrogen excreted annually In domestic sewage is 

 irrecoverable, at any rate by existing methods." 



The present status of nitrogen fixation, A. H, White {Trans. Amer. Inst. 

 Chem. Engin., 11 (1918), pp. 3/^7-365, figs. S). — This is the original of this re- 

 port, previously noted from another source (E. S. R., 41, p. 22). 



I 



