"A've noticed," said Tam, "a deesposition in writin' classes to omit the necessary bits of scenery that throw up the odious villainy of the factor, or the lonely vairtue of the Mill Girl. A forest maiden wi'oot the forest or a hard-workin' factory lass wi'oot a chimney-stalk, is no more convincin' than a seegair band wi'oot the seegair, or an empty pay envelope."

"Why this disquisition on the arts, Tam?" asked Captain Blackie testily.

Three o'clock in the morning, and freezing at that, a dark aerodrome and the ceaseless drum of guns—neither the time, the place nor the ideal accompaniment to philosophy, you might think. Blackie was as nervous as a squadron commander may well be who has sent a party on a midnight stunt, and finds three o'clock marked on the phosphorescent dial of his watch and not so much as a single machine in sight.

"Literature," said Tam easily, "is a science or a disease very much like airmanship. 'Tis all notes of excl'mation an' question mairks, with one full stop an' several semi-comatose crashes—!"

"Oh, for Heaven's sake, shut up, Tam!" said Blackie savagely. "Haven't you a cigar to fill that gap in your face?"

"Aye," said Tam calmly, "did ye no' smell it? It's one o' young Master Taunton's Lubricatos an' A'm smokin' it for an endurance test—they're no' so bad, remembering the inexperience an' youth o' ma wee frien'—"

Blackie turned.

"Tam," he said shortly, "I'm just worried sick about those fellows and I wish—"

"Oh, them," said Tam in an extravagant tone of surprise, "they're comin' back, Captain Blackie, sir-r—a' five, one with an engine that's runnin' no' so sweet—that'll be Mister Gordon's, A'm thinkin'."

Captain Blackie turned to the other incredulously.

"You can hear them?" he asked. "I hear nothing."

"It's the smell of Master Taunton's seegair in your ears," said Tam. "For the past five minutes A've been listenin' to the gay music of their tractors, bummin' like the mill hooter on a foggy morn—there they are!"

High in the dark heavens a tiny speck of red light glowed, lingered a moment and vanished. Then another, then a green that faded to white.

"Thank the Lord!" breathed Blackie. "Light up!"

"There's time," said Tam, "yon 'buses are fifteen thoosand up."

They came roaring and stuttering to earth, five monstrous shapes, and passed to the hands of their mechanics.

"Tam heard you," said Blackie to the young leader, stripping his gloves thoughtfully by the side of his machine. "Who had the engine trouble?"

"Gordon," chuckled the youth. "That 'bus is a—"

"Hec, sir!" said Tam and put his hands to his ears.

They had walked across to the commander's office.

"Well—what luck had you?" asked Blackie.

Lieutenant Taunton made a very wry face.

"I rather fancy we got the aerodrome—we saw something burning beautifully as we turned for home, but Fritz has a new searchlight installation and something fierce in the way of Archies. There's a new battery and unless I'm mistaken a new kind of gun—that's why we climbed. They angled the lights and got our range in two calendar seconds and they never left us alone. There was one gun in particular that was almost undodgable. I stalled and side-slipped, climbed and nose-dived, but the devil was always on the spot."

"Hum," said Blackie thoughtfully, "did you mark the new battery?"

"X B 84 as far as I could judge," said the other and indicated a tiny square on the big map which covered the side of the office; "it wasn't worth while locating, for I fancy that my particular friend was mobile—Tam, look out for the Demon Gunner of Bocheville."

"It is computed by state—by state—by fellers that coont," said Tam, "that it takes seven thoosand shells to hit a flyin'-man—by my own elaborate system of calculation, A' reckon that A've five thoosand shells to see before A' get the one that's marked wi' ma name an' address."

And he summarily dismissed the matter from his mind for the night. Forty-eight hours later he found the question of A-A gunnery a problem which was not susceptible to such cavalier treatment.

He came back to the aerodrome this afternoon, shooting down from a great height in one steep run, and found the whole of the squadron waiting for him. Tam descended from the fuselage very solemnly, affecting not to notice the waiting audience, and with a little salute, which was half a friendly nod, he would have made his way to squadron headquarters had not Blackie hailed him.

"Come on, Tam," he smiled. "Why this modesty?"

"Sir-r?" said Tam with well-simulated surprise.

"Let us hear about the gun."

"Ah, the gun," said Tam as though it were some small matter which he had overlooked in the greater business of the day. "Well, now, sir-r, that is some gun, and after A've had a sup o' tea A'll tell you the story of ma reckless exploits."

He walked slowly over to his mess, followed by the badinage of his superiors.

"You saw it, Austin, didn't you?" Blackie turned to the young airman.

"Oh, yes, sir. I was spotting for a howitzer battery and they were firing like a gas-pipe, by the way, right outside the clock—I can't make up my mind what is the matter with that battery."

"Never mind about the battery," interrupted Blackie; "tell us about Tam."

"I didn't see it all," said Austin, "and I didn't know it was Tam until later. The first thing I saw was one of our fellows 'zooming' up at a rare bat all on his lonely. I didn't take much notice of that. I thought it was one of our fellows on a stunt. But presently I could see Archie getting in his grand work. It was a battery somewhere on the Lille road, and it was a scorcher, for it got his level first pop. Instead of going on, the 'bus started circling as though he was enjoying the 'shrap' bath. As far as I could see there were four guns on him, but three of them were wild and late. You could see their bursts over him and under him, but the fourth was a terror. It just potted away, always at his level. If he went up it lived with him; if he dropped it was alongside of him. It was quaint to see the other guns correcting their range, but always a bit after the fair. Of course, I knew it was Tam and I somehow knew he was just circling round trying out the new gun. How he escaped, the Lord knows!"

Faithful to his promise, Tam returned.

"If any of you gentlemen have a seegair—" he asked.

Half a dozen were offered to him and he took them all.

"A'll no' offend any o' ye," he explained, "by refusin' your hospitality. They mayn't be good seegairs, as A've reason to know, but A'll smoke them all in the spirit they are geeven."

He sat down on a big packing-case, tucked up his legs under him and pulled silently at the glowing Perfecto. Then he began:

"At eleven o'clock in the forenoon," said Tam, settling himself to the agreeable task, "in or about the vicinity of La Bas a solitary airman micht ha' been sighted or viewed, wingin' his way leisurely across the fleckless blue o' the skies. Had ye been near enough ye would have obsairved a smile that played aroond his gay young face. In his blue eyes was a look o' deep thought. Was he thinkin' of home, of his humble cot in the shadow of Ben Lomond? He was not, for he never had a home in the shadow of Ben Lomond. Was he thinkin' sadly of the meanness o' his superior officer who had left one common seegair in his box and had said, 'Tam, go into my quarters and help yourself to the smokes'?"

"Tam, I left twenty," said an indignant voice, "and when I came to look for them they were all gone."

"A've no doot there's a bad character amongst ye," said Tam gravely; "A' only found three, and two of 'em were bad, or it may have been four. No, sir-rs, he was no' thinkin' of airthly things. Suddenly as he zoomed to the heavens there was a loud crack; and lookin' over, the young hero discovered that life was indeed a bed of shrapnel and that more was on its way, for at every point of the compass Archie was belching forth death and destruction"—he paused and rubbed his chin—"Archie A' didn't mind," he said with a little chuckle, "but Archie's little sister, sir-r, she was fierce! She never left me. A' stalled an' looped, A' stood on ma head and sat on ma tail. A' banked to the left and to the right. A' spiraled up and A' nose-dived doon, and she stayed wi' me closer than a sister. For hoors, it seemed almost an etairnity, Tam o' the Scoots hovered with impunity above the inferno—"

"But why, Tam?" asked Blackie. "Was it sheer swank on your part?"

"It was no swank," said Tam quietly. "Listen, Captain Blackie, sir-r; four guns were bangin' and bangin' at me, and one of them was a good one—too good to live. Suppose A' had spotted that one—A' could have dropped and bombed him."

Blackie was frowning.

"I think we'll leave the Archies alone," he said; "you have never shown a disposition to go gunning for Archies before, Tam."

Tam shook his head.

"It is a theery A' have, sir-r," he said; "yon Archie, the new feller, is being tried oot. He is different to the rest. Mr. Austin had him the other night. Mr. Colebeck was nearly brought doon yesterday morn. Every one in the squadron has had a taste of him, and every one in the squadron has been lucky."

"That is a fact," said Austin; "this new gun is a terror."

"But he has no' hit any one," insisted Tam; "it's luck that he has no', but it's the sort of luck that the flyin'-man has. To-morrow the luck may be all the other way, and he'll bring doon every one he aims at. Ma idea is that to-morrow we've got to get him, because if he makes good, in a month's time you won't be able to fly except at saxteen thoosand feet."

A light broke in on Blackie.

"I see, Tam," he said; "so you were just hanging around to discourage him?"

"A' thocht it oot," said Tam. "A' pictured ma young friend William von Archie shootin' and shootin', surroonded by technical expairts with long whiskers and spectacles. 'It's a rotten gun you've got, Von,' says they; 'can ye no' bring doon one wee airman?' 'Gi' me anither thoosand shots,' gasps Willie, 'and there'll be a vacant seat in the sergeant's mess;' and so the afternoon wears away and the landscape is littered wi' shell cases, but high in the air, glitterin' in the dyin' rays of the sun, sits the debonair scoot, cool, resolute, and death-defyin'."

That night the wires between the squadron headquarters and G. H. Q. hummed with information and inquiry. A hundred aerodromes, from the North Sea to the Vosges, reported laconically that Annie, the vicious sister of Archie, was unknown.

Tam lay in his bunk that night devouring the latest of his literary acquisitions.

Tam's "bunk" was a ten-by-eight structure lined with varnished pine. The furniture consisted of a plain canvas bed, a large black box, a home-made cupboard and three book-shelves which ran the width of the wall facing the door. These were filled with thin, paper-covered "volumes" luridly colored. Each of these issues consisted of thirty-two pages of indifferent print, and since the authors aimed at a maximum effect with an economy of effort, there were whole pages devoted to dialogue of a staccato character.

He lay fully dressed upon the bed. A thick curtain retained the light which came from an electric bulb above his head and his mind was absorbed with the breathless adventures of his cowboy hero.

Now and again he would drop the book to his chest and gaze reflectively at the ceiling, for, all the time he had been reading, one-half of his brain had been steadily pursuing a separate course of inquiry of its own; and while the other half had wandered pleasantly through deep and sunless gulches or had clambered on the back of a surefooted bronco up precipitous mountain-slopes, the mental picture he conjured was in the nature of a double exposure, for ever there loomed a dim figure of a mysterious anti-aircraft gun. He took up the book for about the tenth time and read two lines, when a bell in the corner of the room rang three times. Three short thrills of sound and then silence.

Tam slipped from the bed, lifted down his leather jacket from the wall and struggled into it. He took up his padded helmet, switched off the light and, opening the door, stepped out into the darkness. Buttoning his jacket as he went, he made his way across by a short cut to the hangars and found Blackie surrounded by half a dozen officers already on the spot.

"Is that you, Tam? I want you to go up—there she goes!"

They listened.

"Whoom!"

"Fritz has sneaked across in the dark and is industriously bombing billets," he said; "he dodged the Creeper's Patrol. Go and see if you can find him."

"Whoom!"

The sound of the bursting bomb was nearer.

"'Tis safer in the air," said Tam as he swung into his fuselage. "Contact!"

A few seconds later, with a roar, the machine disappeared into the black wall of darkness.

It came back in less than a minute well overhead and Blackie, straining his eyes upward, followed its progress against the stars until it melted into the sky.

"Whoom!"

"He is looking for us," said Blackie; "stand by your hangars."

To the northwest two swift beams of light were sweeping the sky urgently. From a point farther south sprang another beam.

"If Fritz doesn't locate us now he ought to be shot," growled Blackie.

But apparently Fritz had overshot the aerodrome, for the next explosion came a mile to the west.

"Tam will see the burst," said young Austin and Blackie nodded.

There were no other explosions and they waited for ten minutes, then—

"Ticka-ticka-ticka-ticka!"

The sound came from right overhead.

"Tam's got him," whooped Blackie; "the devil must have been flying low."

"Tocka-tocka-tocka-tocka!"

"That's Fritz," said Blackie, "and that's Tam again."

Then one of the waving searchlights strayed in their direction, and down its white beam for the space of a hundred yards slid a ghostly white moth. It dipped suddenly and fell out of the light and in its wake, but above, burst three little green balls of fire—Tam's totem and sign-manual.

"Landing lights!" roared Blackie, and they had hardly been switched on when Tam swooped to the ground.

In the meantime a motor-car had gone swiftly in the direction of the fallen Hun machine.

"He crashed," said Tam breathlessly, as he jumped to the ground; "A'm afeered the puir body is hurt."

But the poor body was neither hurt nor frightened, nor indeed had he crashed.

In point of fact he had made a very good landing, considering the disadvantages under which he labored. They brought him into the mess-room, a tall stripling with shaven head and blue laughing eyes, and he took the coffee they offered him with a courteous little bow and a click of his heels.

"Baron von Treutzer," the prisoner introduced himself.

"I was afraid that a thousand meters was too low to fly, even at night," he said; "I suppose I didn't by any lucky chance get you. By the way, who brought me down? Tam?"

"Tam it was," said Blackie cheerfully, "and you didn't get us."

"I am sorry," said the baron. "May I ask you whether it was Tam who was doing stunts over our new gun?"

Blackie nodded.

"I thought it was. They have been cursing him all the evening—I mean, of course, the technical people," he added hastily, as though to emphasize the fact that the Imperial Air Service was above resentment. "Naturally they swore you had some kind of armor on your machine, and though we told them it was most unlikely, they insisted—you know what obstinate people these manufacturers are; in fact, they say that they saw it glitter," he laughed softly. "You see," he went on, "they don't understand this game. They can not understand why their wonderful"—he corrected himself swiftly—"why their gun did not get you. It would have been a terrible disappointment if they had brought you down and discovered that you were not sheeted in some new patent shell-proof steel."

"Oh, aye," said Tam, and he smiled, which was an unusual thing for Tam to do, and then he laughed, a deep, bubbling chuckle of laughter, which was even more unusual. "Oh, aye," he said again and was still laughing when he went out of the little anteroom.

He did not go back to his bunk, but made his way to the workshop, and when he went up the next morning he carried with him, carefully strapped to the fuselage, a sheet of tin which he had industriously cut and punched full of rivet-holes in the course of the night.

"And what are you going to do with that, Tam?" asked Blackie.

"That is ma new armor," said Tam solemnly. "'Tis a grand invention I made out of my own head."

"But what is the idea?" asked Blackie.

"Captain Blackie, sir-r," said Tam, "I have a theery, and if you have no objection I'd like to try it oot."

"Go ahead," said Blackie with a perplexed frown.

At half-past eleven, Tam, having roved along the German front-line trenches and having amused himself by chasing a German spotter to earth, made what appeared to be a leisurely way back to that point of the Lille road where he had met with his adventures of the previous day. He was hoping to find the battery which he had worried at that time, and he was not disappointed. In the same area where he had met the guns before, they opened upon him. He circled round and located six pieces. Which of these was "Annie"?

One he could silence at terrible risk to himself, but no more. To drop down, on the off-chance of finding his quarry, was taking a gambler's chance, and Tam prided himself that he was no gambler. That the gun was there, he knew. Its shells were bursting ever upon his level and he was bumped and kicked by the violence of the concussions. As for the other guns, he ignored them; but from whence came the danger? He had unstrapped the tin-plate and held it ready in his gloved hand—then there came a burst dangerously near. He banked over, side-slipped in the most natural manner and with all his strength flung the tin-plate clear of the machine. Immediately after, he began to climb upward. He looked down, catching the glitter of the tin as it planed and swooped to the earth.

He knew that those on the ground below thought he was hit. For a brief space of time the guns ceased firing and by the time they recommenced they fired short. Tam was now swooping round eastward farther and farther from range, and all the time he was climbing, till, at the end of half an hour, those who watched him saw only a little black speck in the sky.

When he reached his elevation he began to circle back till he came above the guns and a little to the eastward. He was watching now intently. He had located the six by certain landmarks, and his eyes flickered from one point to the other. A drifting wisp of cloud helped him a little in the period of waiting. It served the purpose of concealment and he passed another quarter of an hour dodging eastward and westward from cover to cover until, heading back again to the west, he saw what he had been waiting for.

Down charged the nose of the machine. Like a hawk dropping upon its prey he swooped down at one hundred and fifty miles an hour, his eyes fixed upon one point. The guns did not see him until too late. Away to his right, two Archies crashed and missed him by the length of a street. He slowly flattened before he came over a gun which stood upon a big motor-trolley screened by canvas and reeds, and he was not fifty yards from the ground when he released, with almost one motion, every bomb he carried.

The explosion flung him up and tossed his little machine as though it were of paper. He gave one fleeting glance backward and saw the dÉbris, caught a photographic glimpse of half a dozen motionless figures in the road, then set his roaring machine upward and homeward.

It was not until a week afterward that the news leaked out that Herr Heinzelle, one of Krupp's best designers, had been "killed on the Western Front," and that information put the finishing touch to Tam's joy.

"But," asked the brigadier-general to whose attention Tam's act of genius had been brought, "how did your man know it was the gun?"

"You see, sir," said Blackie, "Tam got to know that Fritz believed his machine was armored, and he thought they would be keen to see the armor, and so he took up a plate of tin and dropped it. What was more natural than that they should retrieve the armor and take it to the experts for examination? Tam waited till he saw the sunlight reflected on the tin near one of the guns—knew that he had found his objective—and dropped for it!"

"An exceedingly ingenious idea!" said the brigadier.

This message Blackie conveyed to his subordinate.

"A'm no' puffed-up aboot it," said Tam. "'Twas a great waste o' good tin."