This is done by the screw regulating the spring attached to the sounder lever. All these various actions require a specific time in which to operate, and so the transmitting key must be operated very slowly, each dot and dash being given a sufficient length of time for the passage of a good spark. With the Marconi, Slaby, Guarini and all other systems of wireless telegraphy now in use, only twelve to fifteen words per minute can be sent. It is also well to remember that the higher the wires leading up the mast are, the further the messages will carry. Wireless transmission over water can be carried to about ten times as great a distance as over land.
Wireless telegraphy is very much like photography and everything else worth knowing.
To know it well requires care, patience and practice, and the more one keeps everlastingly at it, the greater the results will be.