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LXVII. Litelligence and Miscellaneous Aj'ticles. 



ON THE APPLICATION OF ELECTRO-MAGNETISM AS A MOTIVE 

 POWER. BY MR. ROBERT HUNT. 



A T a recent meeting of the Society of Arts, the author called 

 ^^ attention, in the first place, to the numerous attempts which 

 have been made to apply electro-magnetism as a power for moving 

 machines, and referred to the apparatus employed by Jacobi, Dal 

 Negro, M'Gauley, Wheatstone, Hjorth, and others. Since, not- 

 withstanding the talent which has been devoted to this inter- 

 esting subject, and the large amount of money -which has been 

 spent in the construction of machines, the public are not in posses- 

 sion of any electro -magnetic machine which is capable of exerting 

 any power oeconomically ; and finding that, notwithstanding the aid 

 given to Jacobi by the Russian government, that able experimentalist 

 has abandoned his experimental trials, the author has been induced 

 to devote much attention to the examination of the first principles 

 by which the power is regulated, with the hope of being enabled to 

 set the entire question on a satisfactory basis. 



The phsenomenon of electro-magnetic induction was explained, 

 and illustrations given of the magnetization of soft iron by means of 

 a voltaic current passing around it. The power of electro-magnets 

 was given, and the author stated his belief that this power could be 

 increased almost without limitation. A voltaic current produced by 

 the chemical disturbance of the elements of any battery, no matter 

 what its form may be, is capable of producing by induction a mag- 

 netic force, this magnetic force heiny always in an exact ratio to the 

 amount of matter {zinc, iron, or otherwise) consumed in the battery. 



Several forms of the voltaic battery were explained, particularly 

 those of Daniell, Grove, Bunsen and Reinsch, the latter being con- 

 structed without metals, depending entirely on the action between 

 two dissimilar fluids, slowly combining. 



I'he author had proved, by an extensive series of experiments, 

 that the greatest amount of magnetic power is produced when the 

 chemical action is the most rapid. Hence, in all magnetic machines, 

 it is more oeconomical to employ a battery under an intense action 

 than one in which the chemical action is slow. It has been proved 

 by Mr. Joule, and most satisfactorily confirmed by the author, that 

 one-horse power is obtainable in an electro-magnetic engine the 

 most favourably constructed to prevent loss of power, by the con- 

 sumption of 45 lbs. of zinc, in a Grove's battery, in twenty-four 

 hours ; while 7.5 lbs. are consumed in the same time to produce the 

 same power in a battery of Daniell's construction. The cause of 

 this was referred to the necessity of producing a high degree of ex- 

 citement, to overcome the resistance which the molecular forces 

 oflfer to the electrical perturbations on which the magnetic force 

 depends. 



It was contended, that although we have not perhaps arrived at 

 the best form of voltaic battery, yet that VfQ have learned sufficient 



