THE BEGINNINGS OF KNOWLEDGE 9 



supply of energy. In our modern life where machines 

 for varied purposes are available this control is obtained 

 by means of a switch or button, a faucet or a throttle. 

 It is ours to say whether or not we shall release the 

 energy, but otherwise the operation is inherent hi the 

 design of the machine except in so far as a counter- 

 acting machine, like a brake, may be available. In 

 such a case, this too is controlled by its switch, throttle, 

 or lever. 



A machine, once started and supplied with energy, 

 performs its characteristic series of operations without 

 reference to their effects. In the inevitability of the 

 sequence for which the machine is designed inhere its 

 advantages and dangers. It is therefore vitally neces- 

 sary that those who control machines or come within 

 the range of their motions should bear hi mind this 

 fact. For this reason the old adage of "Look before 

 you leap " has been replaced by the modern slogan of 

 " Safety first." 



The machine requires a source of energy, but does 

 not demand an intelligence or skill on the part of the 

 operator proportional to the results which it produces. 

 While this permits the unskilled to produce the results 

 of the skilled it does not offer the changing conditions 

 which stimulate mental growth. There is a sameness 

 to its operations which may make the human agents 

 mere appendages of the machines they seem to con- 

 trol. The social and economic significance of the 

 machine industry is only beginning to receive from 

 economists and educators the consideration it deserves. 

 Laws on manufacturing conditions and on child labor 

 indicate a growing appreciation on the part of the 



