scend just one
minute by his watch, then took a blanket from his shoulder and with a
quick movement threw it over the smoldering pile, holding two of the
corners tight to the ground, while his companion held the opposite
corners. This, of course, confined the smoke so that no more arose. At
the end of half a minute he raised the blanket three times in quick
succession, and three balloon-shaped clouds floated off over the
sandhills. Waiting half a minute, he lifted the blanket twice, and two
more little clouds arose. At the end of another half a minute he
permitted a single cloud to escape, and then threw the blanket off
altogether; whereupon a long, slender column, like the one that arose
when the fire was first started, shot up into the air. Then Bob seated
himself on the ground and waited rather anxiously for a reply; but he
was not obliged to wait long. Before the five minutes had elapsed an
answering smoke was seen; and though it was a long distance off, the
atmosphere was so clear, and the white clouds showed so plainly against
the blue sky, that the signal could be plainly read. It was the same as
the one Bob had just sent up, and so he knew that it was intended for
him.

This mode of signalling, which is usually called "telegraphing by
smokes," is in general use among the Plains Indians, and it was from
them that our army-officers serving on the border caught the idea. Of
course they have a system of their own, which is very different from
that of the Indians. The latter cannot read an army-signal, and neither
can the officers, with all their striving and scheming, gain a key that
will enable them to read the Indian code. It is as much of a mystery as
the manner in which a chief conducts a drill of his warriors or controls
them in battle without appearing to hold any communication with them.
Both these secrets are closely guarded, the Indians considering that it
would be "bad medicine" to reveal them to the white man.

"Did you see the exact spot from which that smoke arose?" Bob asked of
his companion.

"Yes," answered the trooper.

"Then fix it in your mind, so that you can point it out to George
Ackerman. Now that our work is done we will go back to camp."

Breakfast was soon despatched, and in less than half an hour the squad
was again on the move, three of the troopers, in order to accommodate
the rescued boys and the Indian captive, being obliged to "carry
double." Their route lay along the edge of th