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ME. H. WILDE’S EXPERIMENTAL RESEARCHES 
extremity was connected with the insulated half L' of the commutator by means of a 
clip and binding screw. Bands, encircling the armature at intervals, and sunk below the 
surface of 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 armature 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), 
8 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 diffuse 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 arma- 
ture, 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 electro-magnet. 
18. The first series of experiments with the magneto-electric machine thus described, 
was made for the purpose of ascertaining what influence the number of magnets on the 
cylinder had upon the quantity of electricity generated by the machine, as indicated by 
the galvanometer. 
19. During these investigations, the armature of this machine was driven by steam- 
power at a constant velocity of three thousand revolutions (equivalent to six thousand 
