The conductors are placed upon the iron drum longitudinally and parallel with its axis. But instead of being connected with each other at the posterier end of the armature, as in the Siemens system, they are connected according to chords that correspond to a fourth, a sixth, or any equal fraction whatever of the circumference. Fig. 4 gives a perspective view of the cylinder, upon which the conductors 1, 2, 3, 4, and so on, are placed according to generatrices. The armature is supposed to be divided into six parts, each conductor passing over the bases of the drum through a chord equal to the radius, that is to say, corresponding to a sixth of the circumference. Three conductors are all connected together in such a way as to form but a single circuit closed upon itself. Conductor 1, for example, is connected with No. 6 in such a way that the end issuing from 1 becomes the end that enters No. 6. Conductor No. 3 is connected in the same way with No. 8, and so on, up to the last conductor, which is connected in its turn with the end that enters the first. As the figure shows, the conductor before passing from 3 to 8, for example, returns several times upon itself in following 6 and 3, and the same is the case with all the rest of the winding. [Illustration: FIG. 1. PERSPECTIVE VIEW OF THE THURY MACHINE.] In this way the cylinder becomes inclosed within nine rectangular wire frames, each of which is connected with the following one by a conductor that is at the same time connected with one of the nine plates of the collector. The number of the rubbers corresponds to that of the inducting poles. They may be coupled in different ways, but they are in most cases united for quantity. It will be seen that the Thury armature resembles, in the system of winding, those of the Siemens machines and their derivatives. But it differs from these, however, in the details connected with the coupling of the wires, from the very fact that the features of a two-pole machine are not found exactly in a multipolar one. [Illustration: FIGS. 2 AND 3.] This latter kind of machine is considered advantageous by its inventors, in that there is no need of revolving it with much velocity. It must not be forgotten, however, that although we reduce the velocity by this mode of construction, we are, on another hand, obliged to increase the size of the machine, so that, according to the circumstances under which we chanced to be placed, the advantage may now be on the one side and now on the other. [Illustration: FIGS. 4 AND 5.] It goes without saying that Fig. 4 is essentially diagrammatic, and is designed to give a clearer idea of the mode of winding the armature. In practice the number of the frames, and consequently that of the plates of the conductor, is much greater, and the arrangement that we have described is repeated a certain number of times, the conducter always forming a circuit that is closed upon itself.