TECHNOLOGY AND CIVILIZATION. 715 



off steam, is but a teusion work, (lirt'erin^' 1i'(mii that previously noticed 

 in that it lodges in a physical manner the called forth tension, making 

 it, in truth, a physical tension loorl: This observation carries us furthel', 

 draws ns on, as it were, to the casual connection by which heat is com- 

 municated to the boiler water. This connecting link is the tire, the 

 glowing, flaming coal which gave up chemically, in combustion, the 

 energy stored therein. Thus fire is a chemical tension work made 

 active through kindling, but holding latent, if we consider it in the 

 form of coal, a heat energy stored within by nature's slow process dur- 

 ing millions of years and now eagerly yielded to our simple expedient. 



Thus we have our steam-engine complete ; in the boiler fire a liberated 

 chemical tension work ; in the boiler itself a physical teusion work 

 made active by the fire ; in the engine proper, consisting of stop-cocks, 

 cylinder, and i)iston-work, a mechanical check work, with motive power 

 previously supplied; consequently, as a whole, a general drive work of 

 the third order whereby we slight all secondary mechanisms of j^er- 

 mitted masses. 



But if instead of the simple steam engine with its alternate motion 

 we consider a crank-engine, we have attached to the check work, in the 

 form of the crank motor, a running work, which we can and do use, in 

 thousands of forms ; but the machine thus becomes in this, its most- 

 used variety, a general drive- work of the fourth order. 



Permit me to call attention to still another example taken from steam 

 industry upon the railroad. 



In the locomotive just developed we have before us a drive work of 

 the fourth order. Next come the drive wheels of the engine as run- 

 ning work, friction- wheel work (Reibnider werk), and joining this loco- 

 motive the train gliding over the rails, a self-moving second running 

 work, making, as a whole, a drive work of the sixth order. 



But let our train be of modern form and it will have a Westinghonse 

 brake. The reason of the great favor in which this brake is held and 

 of its great importance our theory explains as follows: 



The brake itself is a catch work formed from a fri(;tion obstruction 

 work which we formerly set in motion with the hand. 



Now we manage otherwise. We have with Westinghouse in the form 

 of the air battery on the train, indeed on every car, a strong, readily- 

 placed tension work which we can at all times easily release through a 

 stopcock in the form of an obstructing ratchet, which the brake con- 

 tracts. Beginning from above, if we follow the brake apparatus, we 

 have before us : Tiie little steam-engine, a check work ; the air pressure 

 pump, a leap work ; the mentioned crank mechanism, a check work ; 

 and the side brtike itself, a catch work ; together a drive work and in- 

 deed a mechanism of the fifth order; and if we add thereto, as we 

 must, steam-boiler and (ire, the whole results as a general drive work 

 of the seventh order. Higher numbers of orders certainly do not be- 

 long to usual contrivances. 



