594 THE POPULAR SCIENCE MONTHLY. 



to turn it with a definite velocity when the exterior current is flowing, 

 and, if the outer circuit is suddenly broken, the machine is seen to ac- 

 quire an increasing velocity, showing that the mechanical force applied 

 to it, being no longer capable of going off as electricity, spends itself 

 then in augmenting the velocity of the moving parts of the machine. 



Ou the other hand, if the machine is kept at a certain speed of 

 revolution while the outer circuit is broken, and the circuit is then 

 suddenly closed, the speed instantly diminishes, showing that a por- 

 tion of the force turning the machine changes into electricity. 



These experiments show that, whether the machine be active or 

 passive, there exists always a state of equilibrium between the ex- 

 penditure of mechanical force and the production of electricity. 

 Quarterly Journal of Science. 



THE STUDY OF SOCIOLOGY. 



Br HEKBERT SPENCER. 



XIV. Preparation in Biology. 



THE parable of the sower has its application to the progress of 

 Science. Time after time new ideas are sown and do not germi- 

 nate, or, having germinated, die for lack of fit environments, before 

 they are at last sown under such conditions as to take root and flourish. 

 Among other instances of this, one is supplied by the history of the 

 truth here to be dwelt on the dependence of Sociology on Biology. 

 Even limiting the search to our own society, we may trace back this 

 idea nearly three centuries. In the first book of Hooker's " Ecclesiasti- 

 cal Polity, 1 ' it is enunciated as clearly as the state of knowledge in his 

 age made possible more clearly, indeed, than was to be expected in 

 an age when science and scientific ways of thinking had advanced so 

 little. Along with the general notion of natural law along, too, with 

 the admission that human actions, resulting as they do from desires 

 guided by knowledge, also in a sense conform to law there is a recog- 

 nition of the fact that the formation of societies is determined by the 

 attributes of individuals, and that the growth of a governmental or- 

 ganization follows from the natures of the men who have associated 

 themselves the better to satisfy their needs. Entangled though this 

 doctrine is with a theological doctrine, through the restraints of 

 which it has to break, it is expressed with considerable clearness : 

 there needs but better definition and further development to make it 

 truly scientific. 



Among reappearances of this thought in subsequent English writ- 

 ers, I will here name only one, which I happen to have observed in 



