Prof. Page un Electro-Magmtisnt us a Moviny Power. 165 



pleted and tried, a gain of one-half horse power was at once realized, 

 and by the addition of a few more feet of battery surface, the power 

 was found to be above four horse. Further addition of battery 

 would still augment the power, and I see no reason why ten-horse 

 power might not be obtained from this engine by the addition of 

 more battery ; but whether it would be ceconomical to increase 

 power by this means alone, and to ascertain the point, for this and 

 every other engine, beyond which oeconomy would cease, by in- 

 creasing the battery alone, are matters to be determined by experi- 

 ment. 



The next most important point to be determined was the expense 

 of this power. Much to my own surprise and gratification, the expense 

 was found to be less than the most expensive steam engines; al- 

 though recently, in Europe, it has been decided by experimenters 

 and men of science, and generally conceded, that it was fifty times 

 the cost of the dearest steam-engines. It is still, however, consi- 

 derably dearer than the cheaper sort of steam-engines; but this is 

 no obstacle to its introduction, considering its immense advantages 

 in other respects. Moreover, if thus much has been done in the 

 very inception of this undertaking, what may we reasonably expect 

 from its further prosecution* ? 



Before it can be rendered available in practice much remains to 

 be done with the galvanic battery, to render its action regular and 

 durable, and in other ways to establish a certainty of action, so that 

 the engines may be managed by persons not thoroughly skilled in 

 the subjects of electricity and magnetism. 



It remains yet also to be proved whether the power will increase 

 in proportion to the size of the engines. This principle seems to be 

 strongly indicated by past experiments, but yet it cannot be esta- 

 blished by calculation or process of reasoning. Experiment upon 

 an extensive scale can alone determine this point. A part of the 

 work preparatory to building a locomotive engine has been done ; 

 but it seems necessary to try further experiments before incurring 

 the expense of another large engine upon the plan above-mentioned. 



* Prof. Page stated in his remarks before the American Association, that 

 one horse power for twenty-four hours would cost about 20 cents. Prof. 

 W. R. Johnson observed that his estimate was based upon too high a cost 

 for the zinc, and that 10 cents Avould he a nearer estimate. In either case, 

 a verj- great advance is made uj)on all previous experiments. 



Prof. Page also observed, that the cost of electro-magnetic power was 

 not to be reckoned in this comparison by the mere cost of zinc, nor the cost 

 of steam by the pounds of coal consumed. The cost of human life, the 

 sacrifice of millions of ])roperty, and risk of many millions more, and iiU 

 the contingent advantages and disadvantages were to be taken into account. 



With regard to his mode of measm-ing the power of the engine, Prof. 

 Page explained as follows after drawing a diagram of the fly-wheel. The 

 brake was loaded to ()20 lbs. The j)ower required barely to keep the en- 

 gine in motion under this load was 12() lbs. The full power being on, the 

 engine made eighty revolutions per minute under this load. The circum- 

 ference of the wheel being about four feet, it was easy for .any one to com- 

 pute the hor>c power from these data. 



