N it Si 



AN ATTEMPT TO DEMONSTRATE A CENTRAL 

 PHYSICAL LAW IN NATURE. 



IT needs not the gift of prophecy to perceive that 

 many changes in philosophy must result from that 

 mighty revolution in society which is now in pro- 

 gress. The philosopher no longer lounges in his 

 chair and dreams away his time in happy confidence 

 in his own opinions, but he has been roused by the 

 events which have startled the monarch on the throne 

 and the priest at the altar, and he now doubts where 

 once he dogmatised. He doubts, and he does not 

 yet divine what the end of his doubts will be. 



Now the creed of science is questioned in nothing 

 more than in the articles which relate to the philo- 

 sophy of the laboratory, and in these articles a change 

 is necessary which is great in itself, but greater still 

 in its results. It is no longer possible to believe 



