There is an advantage in dispensing with the use of the metallic wedge, which is liable to be forgotten by the operator. Third. The attendant may occasionally leave the room, and is not required to be in constant waiting, as the clock work is put in motion and stopped by the operator at the other end, and the message written without his presence. But in the first and second arrangement, the apparatus for putting in motion and stopping the clock work, is entirely useless. The attendant being obliged to put it in motion and stop it himself. We will now proceed to describe the modus operandi of transmitting intelligence from one station to another; the arrangement being as in figure 14; _k_ is the key of the operator at Baltimore, and _m′_ represents his register, or writing desk, at Washington; _k′_ is the key of the operator at Washington, and _m_ his register, or writing desk, at Baltimore. Each has the entire control of his respective register, excepting, only, that each operator winds up the other’s instrument, and keeps it supplied with paper. It will also be borne in mind, that each circuit is complete, and everywhere continuous, except at the keys, which are open. If, then, the hammer is brought in sudden contact with the anvil, and permitted as quickly as possible to break its contact by the action of the spring, and resume its former position, the galvanic fluid, generated at the battery, flies its round upon the circuit, no matter how quick that contact has been made and broken. It has made the iron of the electro magnet a magnet; which has attracted to it the armature of the pen lever; the pen lever, by its steel pen points, has indented the paper, and the pen lever has, also, by the connecting wire with the break; taken it from the friction wheel; this has released the clock work, which, through the agency of the weight, has commenced running, and the two rollers have supplied the pen with paper. But, as only one touch of the key has been made, the clock work soon stops again, if no other touches are made, by the action of the break upon the friction wheel.