[Illustration:  Fig. 54.  Monarch Direct-Current Receiver]

This receiver, like the one of the Automatic Electric Company, does not rely on the shell in any respect to maintain the permanency of relation between the pole pieces and the diaphragm.  The cup 5, which is of pressed brass, contains the voice-current coils and also acts as a seat for the diaphragm.  The entire working parts of this receiver may be removed by merely unscrewing the ear piece from the hard rubber shell, thus permitting the whole works to be withdrawn in an obvious manner.

Dean Receiver.  Of such decided novelty as to be almost revolutionary in character is the receiver recently put on the market by the Dean Electric Company and shown in Fig. 55.  This receiver is of the direct-current type and employs but a single cylindrical bobbin of wire.  The core of this bobbin and the return path for the magnetic lines of force set up in it are composed of soft iron punchings of substantially =E= shape.  These punchings are laid together so as to form a laminated soft-iron field, the limbs of which are about square in cross-section.  The coil is wound on the center portion of this E as a core, the core being, as stated, approximately square in cross-section.  The general form of magnetic circuit in this instrument is therefore similar to that of the Automatic Electric Company’s receiver, shown in Figs. 52 and 53, but the core is laminated instead of being solid as in that instrument.

[Illustration:  Fig. 55.  Dean Steel Shell Receiver]

The most unusual feature of this Dean receiver is that the use of hard rubber or composition does not enter into the formation of the shell, but instead a shell composed entirely of steel stampings has been substituted therefor.  The main portion of this shell is the barrel 1.  Great skill has evidently been exercised in the forming of this by the cold-drawn process, it presenting neither seams nor welds.  The ear piece 2 is also formed of steel of about the same gauge as the barrel 1.  Instead of screw-threading the steel parts, so that they would directly engage each other, the ingenious device has been employed of swaging a brass ring 3 in the barrel portion and a similar brass ring 4 in the ear cap portion, these two being slotted and keyed, as shown at 8, so as to prevent their turning in their respective seats.  The ring 3 is provided with an external screw thread and the ring 4 with an internal screw thread, so that the receiver cap is screwed on to the barrel in the same way as in the ordinary rubber shell.  By the employment of these brass screw-threaded rings, the rusting together of the parts so that they could not be separated when required—­a difficulty heretofore encountered in steel construction of similar parts—­has been remedied.

[Illustration:  Fig. 56.  Working Parts of Dean Receiver]