Fig. 96.
204. Telegraph Sounder. Fig. 96. The magnets, connections, etc., are like those of [App. 121], no binding-posts, etc., being here shown. The armature is straight, however, the part F resting upon D. A hole is made in the end of F, and through this is a screw or nail, S. The hole must be large enough to allow S to pass through easily. This acts as a bearing or pivot. L is kept up against V by the rubber-band, J, one end of which passes around the end of L; to the other end of J is a thread, which is tied around a screw-eye, K. By turning the screw-eye, the band may be made to pull more or less upon L. In this way the apparatus may be regulated according to your battery. The general dimensions and explanations are given in [App. 121]. D is made of such a height that it will bring L about ⅛ or 3⁄16 in. above the poles.
Fig. 97.
205. Telegraph Sounder. Figs. 97 and 98. This apparatus looks a little more like a regular sounder than [App. 121] and [122], but it is much harder to make and adjust. In this the lower nuts of the bolts are not sunk into the base, and the magnets are made of 2-in. bolts. If you change this and fasten them like [App. 89] and [90], it will simply change the dimensions of the small parts. The sizes given are for this particular instrument.
Fig. 97 shows a perspective view, and Fig. 98 is a plan or top-view of it, with dimensions.
