On the earth, rain was falling from gray and gloomy clouds. Above those clouds the sun shone down from a blue sky upon a billowing mass that bore a resemblance to the uneven surface of a limitless plain of lather. High, but not too high above cloud-level, a big white Albatross circled serenely, its long, untidy wireless aerial dangling.

The man in the machine with receivers to his ears listened intently for the faint "H D" which was his official number. Messages he caught—mostly in English, for he was above the British lines.

"Nine—Four.... Nine—four ... nine—four," called somebody insistently. That was a "spotter" signaling a correction of range, then.... "Stop where you are.... K L B Q.... Bad light.... Signal to X O 73 last shot.... Repeat your signal .... No.... Bad light.... Sorry—bad light.... Stay where you are...."

He guessed some, could not follow others. The letter-groups were, of course, code messages indicating the distance shells were bursting from their targets. The apologies were easily explained, for the light was very bad indeed.

"Tam ... MÜller.... Above ... el."

The man in the machine tried the lock of his gun and began to get interested.

Now his eyes were fixed upon the rolling, iridescent cloud-mass below. From what point would the fighting machine emerge?

He climbed up a little higher to be on the safe side. Then, from a valley of mist half a mile away, a tiny machine shot up, shining like burnished silver in the rays of the afternoon sun, for Tam had driven up in a drizzle of rain, and wings and fuselage were soaking wet.

The watcher above rushed to the attack. He was perhaps a thousand yards above his enemy and had certain advantages—a fact which Tam realized. He ceased to climb, flattened and went skimming along the top of the cloud, darting here and there with seeming aimlessness. His pursuer rapidly reviewed the situation.

To dive down upon his prey would mean that in the event of missing his erratic moving foe, the attacker would plunge into the cloud fog and be at a disadvantage. At the same time, he would risk it. Suddenly up went his tail. But Tam had vanished in the mist, for as he saw the tail go up, he had followed suit, and nothing in the world dives like a B. I. 6.

No sooner was he out of sight of his attacker than he brought the nose of the machine up again and began a lightning climb to sunshine. He was the first to reach "open country" and he looked round for MÜller.

That redoubtable fighter reappeared in front and below him and Tam dived for him. MÜller's nose went down and back to his hiding-place he dived. Tam corrected his level and swooped upward again. There was no sign of Captain MÜller. Tam cruised up and down, searching the cloud for his enemy.

He was doing three things at once: He was looking, he was fitting another drum to his gun, and he was controlling the flight of his machine, when "chk-chk-chk" said the wireless, and Tam listened, screwing his face into a grimace signifying at once the difficulty of hearing, and his apprehension that he might lose a word of what was to follow.

"L Q—L Q," said the receiver.

"Noo," said Tam in perplexity, "is 'L Q' meanin' that A' ocht to rin for ma life or is it 'continue the guid wairk'?"

Arguing that his work was invisible from the earth and that a more urgent interpretation was to be put upon the message, he turned westward and dived; not, however, before he had seen over his shoulder a dozen enemy machines come flashing up from the clouds.

"Haird cheese!" said Tam; "a' the auld cats aboot an' the wee moosie's awa'!"

He had intended going home, but a new and bright thought struck him. He turned his machine and pushed straight through the cloud the way he had come. He knew they had seen him disappearing and, airman like, they would remain awhile to bask in the sunlight and "dry off."

As a general rule Tam hated clouds. You could not tell whether you were flying right side up or upside down, and he had always a curious sense of nervousness that he would collide with something. Yet, for once, he drove through the swirling "smoke" with a sense of joyous anticipation, and presently began to rise gently, keeping his eyes aloft to detect the first thinning of the fog. Presently he saw the sunlight reflected on the upper stratas and began to climb steeply. His machine ripped out into the sun, a fierce, roaring little fury.

Not a hundred yards away was a fighting machine.

"Ticka—ticka—ticka—ticka—tick!" said Tam's machine-gun.

Tam's staring blue eyes were on the sights—he could not miss. The pilot went limp in his seat, the observer took his hand from his gun to grip the controls. Too late; the wide-winged fighter skidded like a motorbus on a greasy road and fell into the clouds sideways.

But now the enemy was coming at him from all points of the compass.

"Dinna let oor pairtin' grieve ye!" sang Tam and dropped straight through the clouds into the rain and a dim view of a bedraggled earth.

"There's Burley," said Blackie, clad in a long oilskin and a sou'wester as he checked off the home-coming adventurers. "Do you ever notice how his machine always looks lop-sided? There's Galbraith and Mosen—who's that fellow on the Morane? Oh, yes, that's Parker-Smith. H'm!"

"What's wrong?"

"Where's Tam—I hope those beggars didn't catch him—There he is, the devil!"

Tam was doing stunts. He was side-slipping, nose-diving and looping—he was, in fine, setting up all those stresses which a machine under extraordinary circumstances might have to endure.

"He always does that with a new machine, sir," said Captain Blackie's companion. "I've never understood why, because if he found a weak place, he'd be too dead for the information to be of any service to him."

Later, when Tam condescended to bring himself to earth, Blackie asked him.

"Why do you do fool stunts, Tam? The place to test the machine is on the ground?"

"Ye're wrong, sir-r," said Tam quietly; "the groond's a fine place to test a wee perambulator or a motor-car or a pair of buits—but it's no' the place to test an aeroplane. The aeroplane an' the submarine maun be tried oot in their native eelements."

"But suppose you did succeed in breaking something—and you went to glory?"

"Aye," said Tam quietly, "an' suppose A'm goin' oop wi' matchless coorage to save ma frien's frae the ravishin' Hoon an' ma machine plays hookey? Would it no' be worse for a' concairned, than if A' smash oop by mesel'?"

"Did you see MÜller?"

"In the clouds. A' left him hauldin' a committee-meetin', Captain MacMuller in the cheer.

"'Resolvit,' says the cheerman, 'that this meetin', duly an' truly assembled, passes a hairty vote o' thanks to Tam o' the Scoots, the Mageecian o' the Air-r, for the grand fight he made against a superior enemy—Carried.

"'Resolvit,' says the cheerman, 'that we'll no' ta' onny more risk, but confine oor attentions to strafin' spotters—"

"Carried wi' acclaimation. The meetin' then adjoorned to enquire after machine noomber sax, eight, sax, two, strafed in the execution of ma duty."

It seemed almost as though Tam's words were prophetic, for the next day Smyth and Curzon were attacked whilst "spotting" for the "heavies" and fell in flames in No-Man's Land. They got Smyth in during the night and rushed him back to a base hospital; but Curzon was dead before the machine reached the ground.

The same morning Tam read in the German "Official":

"In the course of the day Captain MÜller shot down his thirtieth enemy aeroplane, which fell before the English lines."

"It were no' the English lines, but the Argyll an' Sootherland Hielanders' lines," complained Tam. "Thairty machines yon Muller ha' strafit. Weel, weel!"

He went to his room very thoughtful, and the day following, being an "off" day, he spent between the machine-shop and the hangar where the B. I. 6 reposed. It must never be forgotten that Tam was a born mechanician. To him the machine had a body, a soul, a voice, and a temperament. Noises which engines made had a peculiar significance to Tam. He not only could tell you how they were behaving, but how they would be likely to behave after two hours' running. He knew all the symptoms of their mysterious diseases and he was versed in their dietary. He "fed" his own engines, explored his own tanks, greased and cleaned with his own hands every delicate part of the frail machinery.

There was neither strut nor stay, bolt nor screw, that he did not know or had not studied, tested or replaced. He cleaned his own gun and examined, leather duster in hand, every round of ammunition he took up. He left little to chance and never went out to attack but with a "plan, an altairnitive plan an'—an open mind."

And now since MÜller must be settled with, Tam was more than careful.

The difficulty about aeroplanes is that they look very much like one another. Tam fought indecisively three big white Albatross machines before a Fokker hawk darted down from the shelter of a cloud-wraith and revealed itself as the temporary preoccupation of Captain MÜller.

The encounter may be told in Tam's own words.

"I' the ruthless pairsuit of his duty, Tam was patrollin' at a height o' twelve thoosand feet, his mind filled wi' beautifu' thochts aboot pay-day, when a cauld shiver passes doon the dauntless spine o' the wee hero. 'Tis a preemonition or warnin' o' peeril. He speers oop an' doon absint-mindedly fingerin' the mechanism of his seelver-plated Lewis gun. There was nawthing in sicht, nawthing to mar the glories of the morn. 'Can A' be mistaken?' asks Tam. 'Noo! A thoosand times noo!' an' wi' these fatefu' wairds, he began his peerilous climb. Maircifu' Heavens! What's yon? 'Tis the mad Muller! Sweeft as the eagle fa'ing upon his prey, fa's MacMuller, a licht o' joy in his een, his bullets twangin' like hairp-strings. But Tam the Tempest is no' bothered. Cal-lm an' a'most majeestic in his sang-frow—a French expression—he leps gaily to the fray—an' here A' am!"

"But, Tam," protested Galbraith, "that's a rotten story. What happened after the lep—did you get up to him?"

"A' didna lep oop," said Tam gravely; "A' lep doon—it wis no' the time to ficht—it wis the time to flee—an' A'm a fleein' mon."

That he would deliberately shrink an issue with his enemy was unthinkable. And yet he rather avoided than sought MÜller after this encounter.

One afternoon he came to Galbraith's quarters. Galbraith was rich and young and a great sportsman.

"Can A' ha'e a waird wi' ye?" asked Tam mysteriously.

"Surely," said the boy. "Come in—you want a cigar, Tam!" he accused.

"Get awa' ahint me, Satan," said Tam piously. "A've gi'en oop cadgin' seegairs an' A' beg ye no' tae tempit a puir weak body. Just puit the box doon whair A' can reach it an' mebbe A'll help mesel' absintminded. A' came—mon, this is a bonnie smawk! Ye maun pay an awfu' lot for these. Twa sheelin's each! Ech! It's sinfu' wi' so many puir souls in need—A'll tak' a few wi' me when A' go, to distreebute to the sufferin' mechanics. Naw, it is na for seegairs A'm beggin', na this time—but ha'e ye an auld suit o' claes ye'll no be wantin'?"

"A suit? Good Lord, yes, Tam," said Galbraith, jumping down from the table on which he was seated. "Do you want it for yourself?"

"Well," replied Tam cautiously, "A' do an' A' doon't—it's for ma frien', Fitzroy McGinty, the celebrated MacMuller mairderer."

Galbraith looked at him with laughter in his eyes.

"Fitzroy McGinty? And who the devil is Fitzroy McGinty?"

Tam cleared his throat

"Ma frien' Fitzroy McGinty is, like Tam, an oornament o' the Royal Fleein' Coor. Oor hero was borr-rn in affluent saircumstances his faither bein' the laird o' Maclacity, his mither a Fitzroy o' Soosex. Fitz McGinty lived i' a graund castle wi' thoosands o' sairvants to wait on him, an' he ate his parritch wi' a deemond spune. A' seemed rawsy for the wee boy, but yin day, accused o' the mairder o' the butler an' the bairglary of his brithers' troosers, he rin frae hame, crossin' to Ameriky, wheer he foon' employment wi' a rancher as coo-boy. Whilst there, his naturally adventurous speerit brocht him into contact wi' Alkali Pete the Road-Agent—ye ken the feller that haulds oop the Deadville stage?"

"Oh, I ken him all right," said the patient Galbraith; "but, honestly, Tam—who is your friend?"

"Ma frien', Angus McCarthy?"

"You said Fitzroy McGinty just now."

"Oh, aye," said Tam hastily, "'twas ain of his assoomed names."

"You're a humbug—but here's the kit. Is that of use?"

"Aye."

Tam gathered the garments under his arm and took a solemn farewell.

"Ye'll be meetin' Rabbie again—A' means Angus, Mr. Galbraith—but A'd be glad if ye'd no mention to him that he's weerin' yeer claes."

He went to a distant store and for the rest of the day, with the assistance of a mechanic, he was busy creating the newest recruit to the Royal Flying Corps. Tam was thorough and inventive. He must not only stuff the old suit with wood shavings and straw, but he must unstuff it again, so that he might thread a coil of pliable wire to give the figure the necessary stiffness.

"Ye maun hae a backbone if ye're to be an obsairver, ma mannie," said Tam, "an' noo for yeer bonnie face—Horace, will ye pass me the plaister o' Paris an' A'll gi' ye an eemitation o' Michael Angy-low, the celebrated face-maker."

His work was interluded with comments on men and affairs—the very nature of his task brought into play that sense of humor and that stimulation of fancy to which he responded with such readiness.

"A' doot whither A'll gi'e ye a moostache," said Tam, surveying his handiwork, "it's no necessairy to a fleein'-mon, but it's awfu' temptin' to an airtist."

He scratched his head thoughtfully.

"Ye should be more tanned, Angus," he said and took up the varnish brush.

At last the great work was finished. The dummy was lifelike even outside of the setting which Tam had planned. From the cap (fastened to the plaster head by tacks) to the gloved hands, the figure was all that an officer of the R. F. C. might be, supposing he were pigeon-toed and limp of leg.

The next morning Tam called on Blackie in his office and asked to be allowed to take certain liberties with his machine, a permission which, when it was explained, was readily granted. He went up in the afternoon and headed straight for the enemy's lines. He was flying at a considerable height, and Captain MÜller, who had been on a joy ride to another sector of the line and had descended to his aerodrome, was informed that a very high-flying spotter was treating Archie fire with contempt and had, moreover, dropped random bombs which, by the greatest luck in the world, had blown up a munition reserve.

"I'll go up and scare him off," said Captain MÜller. He focussed a telescope upon the tiny spotter.

"It looks more like a fast scout than a spotter," he said, "yet there are obviously two men in her."

He went up in a steep climb, his powerful engines roaring savagely. It took him longer to reach his altitude than he had anticipated. He was still below the alleged spotter with its straw-stuffed observer when Tam dived for him.

All that the nursing of a highly trained mechanic could give to an engine, all of precision that a cold blue eye and a steady hand could lend to a machine-gun, all that an unfearing heart could throw into that one wild, superlative fling, Tam gave. The engine pulled to its last ounce, the wings and stays held to the ultimate stress.

"Tam!" said MÜller to himself and smiled, for he knew that death had come.

He fired upward and banked over—then he waved his hand in blind salute, though he had a bullet in his heart and was one with the nothingness about him.

Tam swung round and stared fiercely as MÜller's machine fell. He saw it strike the earth, crumple and smoke.

"Almichty God," said the lips of Tam, "look after that yin! He wis a bonnie fichter an' had a gay hairt, an' he knaws richt weel A' had no malice agin him—Amen!"