"Come on, Ellis," said Lieut. Osborne, rising suddenly. "We've got allwe want now. I'll report to the colonel and probably in a day or twoTourtelle will hear from us again. I'm going to take this cubistsouvenir with me."

  In the course of the conversation he had repacked the section oftattooed skin in the salt, and as he arose to leave he put the box inone of his overcoat pockets. Irving followed him out of the building,and soon they were speeding back over the road by which they had reachedthe field hospital.

  *CHAPTER XV*

  *IRVING AN ORDERLY*

  "We will go direct to Col. Evans' headquarters," Lieut. Osborneannounced shortly after the return trip had been begun. "He asked me toreport back to him as soon as possible."

  The trip was soon made. The colonel's headquarters were less than amile behind the rear line trenches, and the road to this point was infairly good condition.

  Irving felt a deep interest in this visit aside from the bearing it hadon the matter under investigation. He had never seen a colonel'sheadquarters and was curious to know what appearance such a place mightpresent.

  He was not greatly surprised to find it a dugout, although he had notpictured it such in his mind. The first suggestion that had offereditself to him was that the head of the regiment probably had stationedhimself in the palatial residence or chateau of some wealthy fugitivecivilian. However, when the truth appeared to him with the mostcommonplace simplicity, he decided that it was the very thing that heought to have expected.

  The dugout was a two-room affair in the side of a hill on the outskirtsof a small village. The hill was covered with fruit trees and berryvines, affording an excellent camouflage. One of the rooms was occupiedby the colonel and the other by his orderlies. The walls and roof wereof concrete, thick enough to resist heavy bombing from the air. Otherattaches of this headquarters were housed in several homes of theotherwise deserted village.

  The commander of the regiment received the visitors in his elaboratelyfurnished living room, bedroom and dining room. Lieut. Osborne began atonce a rapid account of the interview he had had with Second Lieut.Tourtelle, or Hessenburg. The colonel listened attentively, every nowand then casting a sharp and sometimes lingering glance at PrivateEllis, who had all he could do to suppress the anxious eagerness he feltrelative to impending developments. Naturally, as he had ratherdubiously offered the original information that led up to the partialdisclosure of extensive spy activities, he felt as if his whole futuredepended upon the full success of the investigation.

  Lieut. Osborne opened the box containing the tattooed message and tookit out of its salt packing. Col. Evans examined it curiously while thereporting officer explained all he knew about it, calling attention tothe telegraphic dots and dashes running around the numerous "cubes."

  "We ought to get somebody who is skilled in cryptographic work busy onthis at once," said the colonel. "I've been in communication with thebrigadier general's headquarters and suggested that to them, and nowthat I have this in my possession, I'm going to urge it stronger. I'llget them on the wire again."

  They were seated at a table at one side of the room, and as he spoke,the regiment commander cranked the telephone box at his right and liftedthe receiver to his ear. The conversation was short, for theintelligence department at the brigade headquarters had been busy on thecolonel's suggestion and already had found an expert qualified to probethe mystery of the cubist cryptogram. He would start at once for theregimental headquarters.

  "Just wait here till our cryptologist arrives," said the colonel, afterreporting the result of his conversation over the telephone; "and maybehe'll be able to clear up matters so that we may begin to see bottom."

  The expert, Lieut. Gibbons, attached to the divisional commander'sintelligence staff, arrived half an hour later, and the spy story had tobe told all over again for his benefit, while he examined curiously the"freak-art camouflaged message."

  "I may be able to work this out in a few hours, and then again, it maytake several days," he said. "I'd better take it with me back toheadquarters and work on it there and report back results as soon as Iget them."

  The colonel assented to this and the expert prepared to depart with thecubist cryptogram in his possession. Then the regimental commanderturned to the officer and the private and said:

  "Lieutenant, you will return to your company. I will call on you when Iwish to communicate with you again on this matter. Private Ellis, youwill remain here. I can use another orderly, and, besides, I'd like tohave you close at hand in case of further developments in this spyinvestigation. By the way, can you operate a motorcycle?"

  "Yes, sir," Irving replied.

  "Good. You can be useful at once. I have some papers that I wantdelivered to the brigadier general. You may follow Lieut. Gibbons'automobile and learn the way. He goes past the brigadier general'sheadquarters."

  A motorcycle was soon produced and Irving, after a hurried examinationof it, announced that he understood it thoroughly. A minute later hewas in the saddle and "lickety-chugging" along after the intelligenceofficial's automobile.

  And meanwhile there was buzzing in his brain this new wonder with eagerexpectation:

  "What was the real purpose of Col. Evans in keeping him atheadquarters"? Was that officer likely to have further army detectivework for him to do?

  Already he was beginning to feel like a government secret service man,and he longed to be of further service to his country and the cause ofworld freedom in this romantic line.

  He little dreamed how far beyond the scope of his saner imagination hispatriotic longing was to be realized.

  *CHAPTER XVI*

  *A STARTLING ANNOUNCEMENT*

  Three days later Col. Evans summoned Irving into his dugout office andsaid to him: "Well, the cubist cryptogram has been read."

  The officer smiled with a kind of grim exultation as he spoke. Then headded:

  "And it contained very important information."

  "I'm glad of it," the boy answered simply, although he felt almost as ifhe would burst with a "hurrah!" that threatened to explode within him.

  "Of course you are," the commander concurred. "And I suppose you'd liketo know what's in it."

  "Naturally," Irving replied; "but I doubt very much if you are going totell me."

  "Why?"

  "Because, in the first place, it's none of my business as a private;and, secondly, I presume it is information of a character that the wardepartment wishes to keep secret."

  "Right you are, Ellis. That's the main reason I put the matter up toyou. I wanted to find out what you thought of it. But there's anotherreason why you shouldn't know the contents of that message, and I'lltell you that later. Meanwhile, I have another important matter that Iwant to quiz you on. Do you want to go back to the trenches?"

  "I'm perfectly willing to go back if that is the best thing I can do,"Irving answered readily. "But I'll say this, that if there's any otherplace where I can be of greater service, I prefer to be sent there.It's a question of service pure and simple with me. Naturally, I havemy selfish preferences, but I manage to suppress them."

  "Have you any idea where you could be of greater service than in thetrenches?" asked the colonel.

  "I'll answer your question in this way: I'm sure that the time I spenthelping to run down a dangerous spy was put to much better purpose thanit would have been if spent in the trenches, although I think I did somegood work out in No Man's Land in front of the trenches. But, ofcourse, there's no more of that kind of work left for me to do."

  "Are you sure about that?"

  Irving looked curiously at the putter of this question, considered amoment or two, and then replied:

  "No, I'm not; but I don't know of anything more."

  "Suppose some more of that kind of work should be found, would you liketo do it?"

  "Surely."

>   "Irrespective of the size of the task or the danger?"

  "I don't know how I could find anything much more dangerous than thatskirmish in No Man's Land," Irving replied slowly. "The other part ofyour question I don't wish to answer rashly. Tell me the task, and I'lltell you if it's too big for me."

  "That's the very answer I wanted you to make," said the colonel, almosteagerly. "Now, suppose we should ask you to go over into Germany on animportant spy mission, how would that strike you?"

  This was something Irving was not looking for, and he was so astonishedthat he did not answer for several moments. Then he said:

  "It would strike me all right."

  "Suppose you were given a credential that would effect admittance foryou into high official circles--would you go there and attempt to obtaininformation that might be available, because of your credential?"

  "Yes, sir," Irving replied firmly.

  "What do you think of that stunt of tattooing a message in the form of afreak art production on the arm of Lieut. Tourtelle?"

  Irving smiled.

  "Of course," he said, "it was clever and under ordinary circumstancesought to have been successful; but I'd rather not go through life with athing like that on my arm. It might brand me as a freak, if notsomething worse."

  "I don't blame you," returned the colonel, but as he spoke a peculiarshrewdness lighted his eyes, causing the boy to wonder a little. Then headded: "Still, it might be possible for one to submit to such nonsenseif thereby he might advance a great and worthy cause."

  "Sure, that's quite possible," Irving agreed; "but I don't see howTourtelle, or Hessenburg, can claim any such motive."

  "No, but if he had done it for his own country, the British empire, toadvance the cause of human freedom, what then?"

  "Well, in spite of the ridiculous appearance of the picture on his arm,I'd say he ought to be proud to keep it there. I would. I think I'd beproud to show it. It would be something to show and tell aboutto--to--my great-great-grandchildren when I got old, you see," Irvingfinished with a really illuminating smile.

  "I think I've quizzed you far enough on this subject," Col. Evansannounced at this point, throwing off the manner of vagueness that hadhitherto characterized a good deal of his conversation, and speakingwith unmistakable directness. "I'm now going to ask you to consent tohave that cubist picture tattooed on your arm."

  Irving looked in astonishment at the commanding officer of the regiment,being scarcely able to believe his ears. Surely the proposition wasnonsensical. And, yet, this was no occasion for nonsense. But theboy's wondering conjectures were interrupted by the officer, who wasadding to his last announcement.

  "After the art work on your arm is finished," he said, "I'm going tosend you into Germany to find out some things we want to know."

  "Yes?" Irving responded, with a rising inflection that carried with it asuggestion of an interrogation.

  "Yes," the officer continued; "I want you to take the place of the spywhose tattooed arm had to be amputated."

  *CHAPTER XVII*

  *PARACHUTE PRACTICE*

  Private Ellis looked hard into vacancy and thought just as hard for halfa minute; then he said:

  "I get you, I think, Col. Evans, all except one point; and that, Isuppose, would come to me all right if I knew the contents of thattattooed message."

  "No, you wouldn't," the colonel returned quickly. "It wouldn't do you abit of good."

  "I'd know whether it's important," Irving insisted.

  "I can tell you that much," was the officer's reassurance; "and thenyou're no better off. It's of vast importance and would be ofincalculable value to our enemies if it fell into their hands."

  "Then there's only one explanation of your proposition," Irvingconcluded. "You will change the dots and dashes so that they willconvey information different from that originally intended."

  "Good!" exclaimed the colonel. "You'll do all right. Are you willingto undertake it?"

  "I am," said Irving.

  "Very well. So far so good. Now I'm going to test your nerve somemore. Look out, for this is going to be a corker. If you drop, you'lldrop hard."

  "I'm waiting," said the boy, with a kind of gritty grin.

  "All right. Would you dare make a descent with a parachute from analtitude of several thousand feet?"

  This was a tester, indeed. Irving knew it the instant the last word ofthe question left the colonel's lips, but he did not flinch.

  "Of course, I ought to have some preparation for such a feat," hereplied. "I've never been up in an aeroplane."

  "To be sure," Col. Evans agreed, with a vigorous nod. "You'll get allthe schooling necessary. You'll start out on the venture well equipped.I'm going to send you to the aviation field near brigade headquarters,and there you'll learn to do your umbrella stunt. Then you'll come backhere and go through some more preliminaries. The work of a spy, yousee, is just as much of a science as the handling of an army."

  That ended the interview, and an hour or two later Irving started in anautomobile for the aviation field with a note from the colonel to theflying commander. There he was placed under an expert, and hisschooling in the art of dropping from lofty heights began.

  Private Ellis did not clearly understand just how all this program wasto be carried out, but he had no doubt that Col. Evans had a completeplan in mind and that the missing details would fit in well with whathad already been revealed to him. So he went about his new workconfident that the outlook for success was good.

  His training at the aviation field lasted a week. During that time hemade half a dozen descents by parachute from various altitudes. The lastdescent was from a height of 3,000 feet. By this time the experiencehad become almost as commonplace a thriller as coasting on a longtoboggan slide or "dipping the dips" at an up-to-date amusement park.He had never dreamed that descending with a parachute could become somatter-of-course a performance.

  "I understand now how circus people can look on their death-defyingstunts without being awe-struck with their own daring," he mused afterhe had floated down the fourth time at the rate of three-and-a-half feeta second. "Just think of it: a good swift sprinter would run a hundredyards in about one-third the time that I take to fall thirty-five feet.This is quite a revelation of physical science to me."

  Irving was by nature a very observing youth. His instructor wassomething more than a mere bird-man, for he had studied aviation as amathematical, as well as a physical, science. He showed the boy how tofigure out the rate of falling after being given the diameter of astandard-made parachute and the weight of the aeronaut.

  The parachute with which the young spy-student got his experience as adiver from the sky was one of several supplied for experimental workfollowing reports that the enemy had perfected a similar device whichhad proved successful as a life saver in air battles. But theexperiments of Allied aviators had not proved sufficiently successful towarrant providing all air fighters with "high-dive umbrellas." Descentscould be made with reasonable assurance of safety from aeroplanes flyingin good order, but if a pilot lost control of his machine the chanceswere small that he or his companion gunner or bomb dropper would be ableto leap free from the struts and other framework with a parachute.

  Irving would have liked to learn to pilot an aeroplane, but there wasnot time enough for him to take up that study. Indeed, before half theweek had elapsed he decided he could like no occupation better than thatof an aviator. He saw several expeditions start out to meet the enemy atthe front, and also saw them return, followed by the announcement on twooccasions that several of the British and Canadian flyers who had goneout to meet the foe, full of confidence in their own prowess, wouldreturn no more. They had been either shot down or forced to descendwithin the enemy's lines.

  Nothing was said at the aviation field regarding the reason for thetraining that was being given to Private Ellis. No questions were askedand Irving did not
volunteer any information. At last the instructorstated to the boy that he had completed his course and had learned hislessons well, and that he was now at liberty to seek further directionsfrom the colonel. He accordingly returned to the latter's dugout.

  Col. Evans asked him a number of questions, and then said:

  "I want you to return to the field hospital and get some moreinformation from that spy, Tourtelle, or Hessenburg. And in gettingyour information, remember that you are to impersonate him on the otherside of the Rhine. Now, this is going to be a test of yourspy-intelligence. Let's see how well equipped you can return here afteryour next interview with him. Do you get me, or must I give you sometips?"

  "Don't give me any tips, but let me show you what I can do," Irvingreplied. "If I fall down on this mission, you'll know I'm not thefellow for the job."

  "All right," said the colonel. "I've telephoned for Lieut. Osborne tocome here and accompany you again. But this time, remember, you are todo the quizzing, and the lieutenant is to report to me how efficientlyyou went at it."

  "I'm glad to be put on my own responsibility, sir, before I drop downfrom the clouds into the midst of the enemy," the boy said grimly.

  *CHAPTER XVIII*

  *STUDYING TO BE A SPY*

  An hour later Lieut. Osborne arrived at the colonel's headquarters, andhe and Private Ellis started at once for the field hospital. There theyfound Hessenburg, alias Tourtelle, much improved physically, but not alittle nervous regarding his own rather precarious prospects. Insteadof being an officer helping to direct, in his small way, the battleagainst the autocratic presumption of a great military power, he wassomething more than an ordinary prisoner of war--a trapped spy, who hadconspired with others for the downfall of his own country. Withseemingly genuine repentance, he exhibited much eagerness to give allthe information possible in order to induce leniency for himself from acourt-martial.