1907.] on Problems of Apjylied Chemistry, 573 



now been found. After many unsuccessful attempts at realising for 

 practical purposes the discovery of Cavendish, and after a thorough 

 investigation of its scientific principles by Lord Rayleigh, Muthmann 

 and Hof er, Nernst, Haber, and others, this has been achieved, and once 

 more, by means of that Avell-nigh omnipotent agent, electricity, which 

 thus renders yet another service to mankind. At Notodden, in the 

 Norwegian Hitterdal, a factory has been estabhshed to carry out the 

 process of Birkeland and Eyde, who, by an ingenious application of 

 the extreme heat produced by the electric current, make the nitrogen 

 and oxygen of air combine to nitric oxide, which at a lower tempera- 

 ture is spontaneously oxidised into nitrous vapours, with the ultimate 

 production of nitrites or nitrates. This time there is really no 

 doubt that a practicable and economical process has been discovered 

 for which it is intended to employ, by the end of this year, water 

 power to the extent of 80,000 H.P. The Notodden process bids fair 

 to be followed by other even more efficient processes. The most 

 important of these is that of the Badische Anilin- and Soda-Fabrik, for 

 which an experimental factory is in course of construction, and for 

 which 50,000 H.P. are to be employed. But for some time to come 

 .the Chilian saltpetre will still rule the trade ; a very large amount of 

 water power will, indeed, have to be brought into use merely to 

 cover the annual increment of consumption of this commodity for 

 agricultural purposes. 



One task it is certain that explosives will never fulfil, and that 

 was suggested to me by one of the cleverest mechanical engineers I 

 have known. He w^as intensely interested in the problem of aerial 

 navigation, and for this purpose he wished to construct an engine 

 worked by fuel of the most concentrated kind. Neither coal, nor 

 benzine, nor oil would do. In his plight he came to me and asked 

 what explosives I should advise him to try for working his engine, in 

 the erroneous idea that explosives were a kind of concentrated fuel. 

 Of course, I could not but reply as follows : All honour to his courage, 

 but no explosive known, so far ever or likely to be invented, could 

 possess that property he required, viz. a large store of energy. A 

 pound of coal represents five times as much energy as a pound of the 

 strongest explosive known — ^blasting gelatine. My friend had over- 

 looked the fact that a pound of dynamite, though it gives out nearly 

 150 million horse-power, does so only for the space of s-q.Wo of a 

 second. He had omitted to take into account the element of time, 

 and had confused potver in the ordinary sense with energy, which 

 is the capacity for doing work. 



A similar confusion is sometimes made between energy and the 

 creation of high temperatures. This can be very well illustrated by the 

 use recently made of finely powdered aluminium, both as a component 

 of explosives and as an agent for producing very high temperatures, 

 in the shape of Dr. Goldschmidt's " thermite." In both cases the 

 fact is utilised that aluminium is easily, and in the shape of fine 



