446 THE PRINCIPLES OF SCIENCE. 



nated in a heated revolving nebulous mass of gas, and 

 is in a state of almost infinitely slow progress towards the 

 cold and stony condition) Other speculative hypotheses 

 might doubtless be entertained. Every hypothesis is 

 pressed by difficulties. If the whole universe be cooling, 

 where does the heat go to ? If we are to get rid of it 

 entirely, outer space must be infinite in extent, so that it 

 shall never be stopped and reflected back. But not to 

 speak of metaphysical difficulties, if the medium of heat 

 undulations be infinite in extent, why should not the 

 material bodies placed in it be infinite also in number and 

 quantity. It is quite apparent that we are venturing 

 into speculations which altogether surpass our powers 

 of scientific inference. But then I am arguing nega- 

 tively ; I wish only to show that those who speak of 

 the uniformity of nature, and the reign of law, often 

 misinterpret ^entirely the meaning involved in those 

 expressions. (Law is not inconsistent with extreme di- 

 versity,) and, so far as we can read the history of this 

 planetary system, it did most probably originate in heated 

 nebulous matter, and man's history forms but a moment 

 in its progress towards the cold and stony condition. It 

 is by very doubtfu] and speculative hypotheses alone that 

 we can avoid such a conclusion, and I depart least from 

 undoubted facts and well-established laws, when I assert 

 that, ^whatever uniformities may underlie the phenomena 

 of nature, 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 pro- 

 gressing from some act of creation, or some discon- 

 tinuity of existence of which the date may be approxi- 



