in Magnetism and Electricity. 85 



the iron in grooves turned out for their reception, prevented the 

 convolutions of insulated wire from flying out of position by the 

 centrifugal force attending their rapid revolution. The arma- 

 ture is represented complete in fig. 6, and in section in fig. 7. 



12. A number of exactly similar permanent magnets (of the 

 form shown in fig. 1), 9 inches long, were made from bars of 

 steel 1 inch wide and a quarter of an inch thick, and the distance 

 between the inner edges of the polar extremities of the magnets 

 was a little less than 2 inches. The magnets weighed about one 

 pound each; and they received very nearly equal degrees of 

 magnetism, which enabled them to support a weight of about 

 ten pounds each. 



13. On each side of the magnet-cylinder was a flat raised 

 surface, M, M, figs. 2, 3, extending the whole length of the 

 cylinder between the projections E, E. These surfaces were 

 planed parallel with each other and with the axis of the magnet- 

 cylinder. When the magnets, the legs of which were somewhat 

 less than 2 inches apart, were sprung upon the cylinder in the 

 position shown in fig. 1, they were held in sufficiently good 

 contact for the magnetism to diifuse itself equally throughout 

 the entire mass of the cylinder ; the two cast-iron sides of which, 

 consequently, formed the poles of the magnets. On the lower 

 part of the magnet-cylinder four projections or feet, N, N, N, N, 

 figs. 2, 3, were cast, by means of which it was bolted firmly to 

 a wooden base. 



14. When the armature was made to revolve rapidly in the 

 interior of the magnet-cylinder, waves of magneto-electricity 

 were generated in the coils by the reversals of the magnetism in 

 the rib G ; and from the peculiar construction of the cylinder 

 and armature, two waves of electricity, moving in alternate 

 directions, were generated for each revolution of the armature. 



15. The rapid succession of alternating waves thus generated 

 could be taken from the machine as an intermittent current 

 moving in one direction, by means of two steel springs (shown 

 in the perspective drawing, fig. 10), when they were made to 

 rub against the opposite sides of the commutator L. 



16. The waves of electricity could also be taken in alternate 

 directions from the machine when required, by adjusting the 

 springs so as to rub against the unbroken cylindrical part of 

 each half of the commutator. 



17. The springs were placed in metallic connexion with the 

 respective polar terminals of the machine, and to these terminals 

 wires were attached for making the necessary connexions with 

 those of a galvanometer or of an electromagnet. 



18. The first series of experiments with the magneto-electric 

 machine thus described, was made for the purpose of ascer- 



