AMERICAN INSTITUTE. 563 



doubly limited. Either its most formidable agent, a fall of 

 water, is not found where the work is to be done, or else an 

 equal amount of power, obtained from other soui-ces, must re- 

 peatedly restore the opportunity for its brief action. When it is 

 asserted by the deviser of a so-called " perpetual motion," that 

 because so slight a consumption of power at distant intervals will 

 propel a small wheel, propoitionably slight expenditures and 

 distant intervals, will promote the rotation of a large one, and so 

 on unlimitedly, the practical fallacy is exposed by a fact, that 

 just so much force is required to produce a given amount of 

 motion, and that if his apparatus is entirely abandoned, and con- 

 sumes none at all, so much the more force is left to do the work. 



But the use of gravitation as a motive power on railways, is 

 not a mere speculation. When an abundance of water flows 

 down an inclined plane, up which loads are to be carried, by the 

 introduction of common appliances, the cost of transportation 

 may be made a question of mere w^ear and tear of machinery. 

 And wlien such application is made at the bottom of the incline, 

 that same steepness which necessitates increased power, at once 

 furnishes that power, in the additional head and velocity of the 

 stream. But if the water is applied to the locomotive as it 

 ascends the grade, as an European engineer has proposed, and 

 perhaps applied, a force at the bottom which would sweep away 

 the entire enginery, would, at the top, hardly overcome its fric- 

 tion. Gravitation may primarily and remotely facilitate loco- • 

 motion, but it is evidently not the grand motor. 



Electricity is the most powerful, though by far the most subtle 

 of natural forces. Next perhaps to steam, its nature and appli- 

 cation to locomotion have invited the greatest amount of scien- 

 tific research and inventive talent. Electrical engines have, so 

 far, depended for the generation of power upon the galvanic bat- 

 tery, and they have failed in that important item, economy. If 

 zinc, in combination with copper, be decomposed by sulphuric 

 acid, it is burned by the oxygen of the acid, thereby producing an 

 electrtc current of sufficient power to raise a given weight. If 

 this current be continually broken and renewed by certain me- 

 chanical appliances, the weight may be made to assume a recipro- 

 cating or a circular motion, and to impel any variety of ma- 

 chinery, with a force exactly proportionate to the oxidation and 

 consumption of the zinc. But if the zinc be burned under a steam 

 boiler, the power generated will be only one-sixth of that which 

 would be produced by a given amount of r^arbon in the shape of 



