Chester called off the many dog names familiar to him, and Hal added a few. But, although the animal wagged his tail with evident pleasure at thus being talked to, he gave no evidence of owning any of the names in the boys' vocabulary. Hal approached and laid his hand on the dog's head. Then, for the first time, he noticed the collar he wore. "Hello!" he said, in some surprise. "What is it?" said Chester, also approaching. "Collar," said Hal briefly. "Perhaps his name is on it." Both boys bent over the dog. "Here it is, sure enough," cried Chester. "Can you make it out?" asked Hal. "It's a little dark," replied the lad. "Bring him over here nearer the light." This was done, and once more Chester bent over the collar. "Well?" demanded Hal. "Yes, I can read it," replied Chester. "What is it?" demanded Hal. Chester read aloud: "Marquis--Twenty-third French Infantry." "A dispatch dog, eh?" said Hal. "Yes," said Chester; "and, if I mistake not, a very valuable addition to our party." CHAPTER XXXI. BERLIN ONCE MORE. By dint of persuasion the German officer succeeded in gaining the consent of General Von Kluck to allow the boys to take the dog with them. That Marquis was just as pleased to go as the boys were to have him, was plainly evident. When they left their tent for the last time, and whistled to him to follow, he bounded after them with enthusiasm. The train on which the boys were to be taken back to Berlin did not leave until well along toward midnight, but, with some 5,000 other prisoners, British, French and Belgians alike, they were bundled aboard early. Heavily guarded, and without a weapon of any kind or description, there was no fear of a break for liberty, in spite of the large number of prisoners. The lads were shoved into a car already loaded down with prisoners and took their positions at the far end, the dog between them. In spite of misfortune, the prisoners all were far from unhappy. They joked and chatted as though they were on a pleasure trip. Finally, after much delay, the train started with a jolt, tumbling men all over each other as it gradually gathered momentum. They were hurled hither and yon, but they only laughed. The trip was necessarily slow, for the train, time after time, was switched on to a siding to permit of the movement of German troop trains carrying soldiers from the western theater of war to the east, or from the east to the west. Consequently, it was late the following night when the train finally pulled in, and the prisoners were ordered to get out. Under the leveled rifles of a strong German guard, they stepped to the ground, and, after being divided into squads at the direction of the German officer in command, were marched away. Hal, Chester and Marquis were among the last to leave the train. As the dog tumbled out after them, there was an exclamation from a German officer.