The younger boy ceased his efforts to close the gates, and advancing a few steps before the entrance of the fort, looked up the valley to where the road from Prescott appeared from behind a spur of the foot-hills.  The two boys had mounted their sergeant’s chevrons and adopted white stripes down the legs of their trousers.  As they stood side by side Vic approached and placed herself between them, nestling her delicate muzzle against the younger boy’s hip and responding to his caresses with waves of her plumy tail.

“Do you think we shall hear from father, Frank?”

“We ought to; you know he said in his last letter he was getting settled at the Presidio, and would soon send for us.”

“Takes twelve days to bring a letter from San Francisco.  I suppose it’ll take us longer to go there; seems to me he might get ready for us while we are on the road,” said Henry, lugubriously.  “I’m getting mighty tired of opening and shutting these gates.”

“You forget father has to visit all the posts where companies of his regiment are stationed.  That will probably take him all of a month longer.”

“And we must go on opening and closing gates and running errands in Arizona?  But come; let’s get a swing on ’em and watch for the expressman afterwards.  We haven’t much time before retreat.”

The gates closed a fort which we had built since our arrival in Arizona.  Peeled pine logs, ten feet long, had been set up vertically in the ground, two feet of them below the surface and eight above, enclosing an area of a thousand square feet, in which were store-rooms, offices, and quarters for two companies of soldiers and their officers.  At corners diagonally opposite each other were two large block-house bastions, commanding the flanks of the fort.  The logs of the walls were faced on two sides and set close together, and were slotted every four feet for rifles.  At one of the corners which had no bastions were double gates, also made of logs, bound by cross and diagonal bars, dovetailed and pinned firmly to them.  Each hung on huge, triple hinges of iron.

The two boys returned to the gates, and, setting their backs against one of them and digging their heels in the earth, pushed and swung it ponderously and slowly, until its outer edge caught on a shelving log set in the middle of the entrance to support it and its fellow.  Then, as the field-music began to play and the men to assemble in line for retreat roll-call, they swung the second gate in the same way, and braced the two with heavy timbers.  The boys then reported the gates closed to the adjutant.

As the companies broke ranks and dispersed the boy sergeants went to the fifth log, to the left of the gates, and swung it back on its hinges.  This was one of two secret posterns.  On the inside of the wall, when closed, its location was easily noticeable on account of its hinges, latches, and braces; on the outside it looked like any other log in the wall.  Their work being completed, the boys asked permission of the adjutant to stand outside the wall and watch for the mail.