Page:Popular Science Monthly Volume 3.djvu/424

410 are of two lengths, one being made as short as possible (-), and called a dot, and the other being about three times as long, and called a dash. The opposing spring (D) restores the armature to its original position the moment the current ceases.



Morse's key (Fig. 11) is simply a brass lever, mounted on a hinge at A, and pressed up by the spring f. When the operator puts down the key, by pressing on the button (K) with his finger, the projections



(c d) are brought into contact, and a current passes from the battery-wire (P) to the line-wire (L). When the key is up, the projections (a b) are in contact, and currents arriving by the line-wire pass by the wire R to the indicator or the relay. By keeping the key down for a longer