the lug 7 of the hook and thus tend to raise the hook when it is relieved of the weight of the receiver.  The two shorter springs 8 and 9 have no electrical function but merely serve as supports against which the springs 4 and 5 may rest, when the receiver is on the hook, these springs 4 and 5 being given a light normal tension toward the stop springs 8 and 9.  It is obvious that in the particular arrangement of the springs in this switch no contacts are closed when the receiver is on the hook.

[Illustration:  Fig. 84.  Short Lever Hook Switch]

Concerning this latter feature, it will be noted that the particular form of Kellogg hook switch, shown in Fig. 83, makes two contacts and breaks two when it is raised.  Similarly the Western Electric Company’s makes two contacts but does not break any when raised.  From such considerations it is customary to speak of a hook such as that shown in Fig. 83 as having two make and two break contacts, and such a hook as that shown in Fig. 84 as having two make contacts.

It will be seen from either of these switches that the modification of the spring arrangement, so as to make them include a varying number of make-and-break contacts, is a simple matter, and switches of almost any type are readily modified in this respect.

[Illustration:  Fig. 85.  Removable Lever Hook Switch]

Dean.  In Fig. 85 is shown a decidedly unique hook switch for wall telephone sets which forms the standard equipment of the Dean Electric Company.  The hook lever 1 is pivoted at 2, an auxiliary lever 3 also being pivoted at the same point.  The auxiliary lever 3 carries at its rear end a slotted lug 4, which engages the long contact spring 5, and serves to move it up and down so as to engage and disengage the spring 6, these two springs being mounted on a base lug extending from the base plate 7, upon which the entire hook-switch mechanism is mounted.  The curved spring 8, also mounted on this same base, engages the auxiliary lever 3 at the point 9 and normally serves to press this up so as to maintain the contact springs 5 in engagement with contact spring 6.  The switch springs are moved entirely by the auxiliary lever 3, but in order that this lever 3 may be moved as required by the hook lever 1, this lever is provided with a notched lug 10 on its lower side, which notch is engaged by a forwardly projecting lug 11 that is integral with the auxiliary lever 3.  The switch lever may be bodily removed from the remaining parts of the hook switch by depressing the lug 11 with the finger, so that it disengages the notch in lug 10, and then drawing the hook lever out of engagement with the pivot stud 2, as shown in the lower portion of the figure.  It will be noted that the pivotal end of the hook lever is made with a slot instead of a hole as is the customary practice.