True to his word, five minutes later a large-winged biplane stood before them.

“You will have to run this thing,” Chester whispered to Hal.

“Well, it won’t be the first time,” Hal whispered back.

Hal took the aviator’s seat and Chester also took his place.  Then the latter whistled to Marquis, who came bounding up and sprang in and sat down calmly between Chester’s feet.

“Surely you are not going to take that dog,” protested the commandant.

“Yes,” said Chester.  “He is one of the dispatch dogs taken from the French.  We are going to make use of him with a false dispatch.”

“I see,” exclaimed the commandant, “A good idea.”

“Isn’t it?” said Chester.

“All ready?” demanded the commandant of Hal.

“All ready,” was the lad’s reply.

“Let her go, then,” the commandant ordered the two men who had appeared to give the aeroplane a start.

A moment later and the machine was speeding along the ground.

“Good luck,” called the commandant.

Chester waved his hand in reply.

Now Hal touched the elevating lever, and the aeroplane left the ground, and, soaring high in the air, sped on its way.

“Which way, Chester?” Hal called back over his shoulder.

“Due east,” replied Chester, “but first rise as high as you can.”

Hal obeyed this command, and soon the two boys and a dog were thousands of feet above the earth.

“What’s your altitude?” called Chester.

Hal told him.

“Good!” said Chester.  “Keep her there, and now head due east.”

Quickly Hal brought the big aircraft about, and pointed her nose in a direction that eventually, barring accidents and the misfortunes of war, would land them in the heart of Poland, where the mighty armies of Russia were rushing upon the German legions.

“I know we shall get through safely,” called Chester, as they sped along.  “Some way I feel it.”

“And so do I,” Hal called back.

They were right, and before another night had fallen these two young American boys placed in the hands of the Grand Duke Nicholas, commander-in-chief of the mighty hordes of the Czar, the paper which had so strangely fallen into their hands—­the paper which, later on, brought about more than one serious check to German arms.

But here ends the story of the Boy Allies along the Marne.  Their further adventures will be told in a succeeding volume, entitled, “The Boy Allies With the Cossacks; or a Wild Dash Over the Carpathian Mountains.”