The Chemist as Creator 757 



be made at home. There are some Swiss valleys nowadays which 

 are "glacier at one end and 98 per cent, nitric acid at the other." 

 The chemist has discovered how to make fertilisers and there- 

 fore bread out of the thin air. 



It has been known for a long time that a flash of lightning 

 passing through the air may separate nitrogen atoms fro'm one 

 another and oxygen atoms from one another, with the results 

 that some of the isolated nitrogen atoms unite with some of the 

 oxygen atoms and yield nitric oxide the first step to something 

 better. What the chemist did was to substitute for the lightning 

 a gigantic electric arc through which the air is run rapidly, lest 

 the terrific temperature, e.g. 6,300 Fahrenheit, undo what it has 

 done. When the energy for producing the electric arc can be 

 obtained from a handy waterfall, whether natural or artificial, 

 the relative cheapness of tapping the store of free nitrogen in the 

 air is evident. 



In Germany, where water-power is not so available as in 

 Scandinavia, they hit upon another way of capturing the nitrogen 

 of the air the well-known Haber process. The elements used 

 in this case are nitrogen and hydrogen, the result is ammonia 

 (NHs), and the agent is not an electric furnace but a quietly- 

 working rare metal, such as uranium, osmium, or platinum, which 

 acts in a mysterious way (as a "catalyst"), bringing elements 

 that become intimate with it into union with one another. It is 

 not to be supposed that the Haber process is a simple affair, for 

 great pains have to be taken to get the nitrogen and the hydrogen 

 in a very pure state before they are submitted to the catalytic 

 action of the rare metal. Moreover, when the ammonia has been 

 produced it has to be changed into the more useful form of nitric 

 acid, which involves another appeal to a catalyst (a platinum 

 gauze) in the Ostwald process. The extent to which the air is 

 to-day "worked" for raw materials is very wonderful; such, for 

 example, as oxygen, which is used extensively in engineering 

 industries with acetylene to make intensely hot flame for welding 



VOL. Ill tj 



