PHYSICS 



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ments of the quantity of heat thus generated have 

 shown that in proportion to the amount of material 

 decomposition taking place, it is of an altogether 

 higher order of magnitude, in fact a million or 

 more times greater, than that generated in chemical 

 reactions such as the combustion of coal. Owing 

 to the difficulty of concentrating considerable 

 quantities of intensely radioactive materials, this 

 spontaneous generation of heat is not likely to 

 prove economically important, although, owing 

 to the wide dissemination of the radioactive 

 elements, it may be an important factor in main- 

 taining the heat of the earth and the celestial 

 bodies. 



The disruption of hydrogen from the nitrogen 

 nucleus by Rutherford has shown that a similar 

 process is to a certain extent under our control, 

 and is operative with elements which are available 

 in almost unlimited quantity. It is clear that if 

 this artificial disintegration of the elements is 

 accompanied by a development of heat of the 

 same order of magnitude as that generated in 

 the spontaneous disintegration of the radioactive 

 elements, and if it can be started and controlled 

 without undue expenditure of energy, we shall 

 have obtained a prime source of energy which 

 will make all the present sources fade into insig- 

 nificance. These are large questions which it 

 may take some time to answer satisfactorily, but 



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