xxxi.J LIMITS OF SCIENTIFIC METHOD. 751 



constant variety and ever-progressing change is the real 

 outcome. 



Speculations on the Reconcentration of Energy. 



There are unequivocal indications, as I have said, that 

 the material universe, as we at present see it, is progressing 

 from some act of creation, or some discontinuity of exist- 

 ence of which the date may be approximately fixed by 

 scientific inference. It is progressing towards a state in 

 which the available energy of matter will be dissipated 

 through infinite surrounding space, and all matter will 

 become cold and lifeless. This constitutes, as it were, the 

 historical period of physical science, that over which our 

 scientific foresight may more or less extend. But in this, 

 as in other cases, we have no right to interpret our ex- 

 perience negatively, so as to infer that because the present 

 state of things began at a particular time, there was no 

 previous existence. It may be that the present period of 

 material existence is but one of an indefinite series of like 

 periods. All that we can see, and feel, and infer, and 

 reason about may be, as it were, but a part of one single 

 pulsation^ in the existence of the universe. 



After Sir W. Thomson had pointed out the prepon- 

 derating tendency which now seems to exist towards the 

 conversion of all energy into heat-energy, and its equal 

 diffusion by radiation throughout space, the late Professor 

 Rankine put forth a remarkable speculation. He suggested 

 that the ethereal, or, as I have called it, the adamantine 

 medium in which all the stars exist, and all radiation 

 takes place, may have bounds, beyond which only empty 

 space exists. All heat undulations reaching this boundary 

 will be totally reflected, according to the theory of undu- 

 lations, and will be reconcentrated into foci situated in 

 various parts of the medium. Whenever a cold and 

 extinct star happens to pass through one of these foci, it 

 will be instantly ignited and resolved by intense heat into 

 its constituent elements. Discontinuity will occur in the 

 history of that portion of matter, and the star will begin 

 its history afresh with a renewed store of energy. 



1 Report of the British Association (1852), Report of Sections, p. 12. 



