ther, without being directly connected, hence the name
"wireless," though really some wires are used.

The electrical impulse can be sent for thousands of miles through the
air, without any directly connecting wires. And the method of
communication is by means of dots, dashes and spaces.

You have doubtless heard the railroad or other telegraph instruments
clicking. You can hold your table knife blade between two tines of
your fork, and imitate the sound of the telegraph very easily.

If you move your knife blade up and down once, quickly, that will
represent a dot. If you move it more slowly, holding it down for a
moment, that would be a dash. A space would be the interval between a
dot and a dash, or between two dots or two dashes.

Thus, by combinations of dots, dashes and spaces, the letters of the
alphabet may be made and words spelled out. For instance a dot and a
dash is "A."

In telegraphing, of course, the operator listens to the clicking of the
brass sounder in front of him on the desk. But in wireless the
electrical waves, or current received, is so weak that it would not
operate the sounder. So a delicate telephone receiver is used. This is
connected to the receiving wires, and as the sender at his station,
perhaps a thousand miles away, presses down his key, and allows it to
come up, thus making dots, dashes and spaces, corresponding clicks are
made in the telephone receiver, at the ear of the other operator.

It takes skill to thus listen to the faint clicks that may be spelled
out into words, but the operators are very skillful. In sending
messages a very high tension current is needed, as most of it is
wasted, leaping through the air as it does. So that though the clicks
may sound very loud at the sending apparatus, and the blue sparks be
very bright, still only faint clicks can be heard in the head-telephone
receiver at the other end.

"You may send," directed Captain Grantly to Captain Wakefield, and the
blue sparks shot out in a dazzling succession, as the spiked wheel spun
around. This was kept up for some little time, after the receiving
operator at the army headquarters had signified that he was at
attention. Then came a period of silence. Captain Wakefield was
receiving a message through space, but he alone could hear this through
the telephone receiver.

He wrote it out in the cipher code, and soon it was translated.

"I informed them that we had arrived safely," said Captain