278 ON THE CONSERVATION OF FORCE. 



peoples is also in conformity with law, as is the object of philo- 

 sophical, philological, historical, moral, and social sciences to 

 establish. But in mental life, the influences are so interwoven, 

 that any definite sequence can but seldom be demonstrated. In 

 Nature the converse is the case. It has been possible to discover 

 the law of the origin and progress of many enormously extended 

 series of natural phenomena with such accuracy and complete- 

 ness that we can predict their future occurrence with the greatest 

 certainty ; or in cases in which we have power over the con- 

 ditions under which they occur, we can direct them just accord- 

 ing to our will. The greatest of all instances of what the 

 human mind can effect by means of a well-recognised law of 

 natural phenomena is that afforded by modern astronomy. The 

 one simple law of gravitation regulates the motions of the 

 heavenly bodies not only of our own planetary system, but also of 

 the far more distant double stars; from which, even the ray 

 of light, the quickest of all messengers, needs years to reach our 

 eye; and, just on account of this simple conformity with law, 

 the motions of the bodies in question can be accurately pre- 

 dicted and determined both for the past and for future years and 

 centuries to a fraction of a minute. 



On this exact conformity with law depends also the certainty 

 with which we know how to tame the impetuovis force of steam, 

 and to make it the obedient servant of our wants. On this 

 conformity depends, moreover, the intellectual fascination which 

 chains the physicist to his subjects. It is an interest of quite a 

 different kind to that which mental and moral sciences afford. 

 In the latter it is man in the various phases of his intellectual 

 activity who chains us. Every great deed of which history tells 

 us, every mighty passion which art can represent, every picture 

 of manners, of civic arrangements, of the culture of peoples of 

 distant lands or of remote times, seizes and interests vis, even if 

 there is no exact scientific connection among them. We con- 

 tinually find points of contact and comparison in our own con- 

 ceptions and feelings ; we get to know the hidden capacities and 

 desires of the mind, which in the ordinary peaceful course of 

 civilised life remain unawakened. 



