There arrived one day at the aerodrome a large packing-case addressed "Sergeant Tam." There was no surname, though there was no excuse for the timidity which stopped short at "Tam." The consignor might, at least, have ventured to add a tentative and inquiring "Mac?"

Tam took the case into his little "bunk" and opened it. The stripping of the rough outer packing revealed a suave, unpolished cedar cabinet with two doors and a key that dangled from one of the knobs. Tam opened the case after some consideration and disclosed shelf upon shelf tightly packed with bundles of rich, brown, fragrant cigars.

There was a card inscribed:"Your friend in the Merman pusher."

"Who," demanded Tam, "is ma low acqueentance, who dispoorts himsel' in an oot-o'-date machine?"

Young Carter, who had come in to inspect the unpacking, offered a suggestion.

"Probably the French machine that is always coming over here to see you," he said, "Mr. Thiggamy-tight, the American."

"Ah, to be sure!" said Tam relieved. "A' thocht maybe the Kaiser had sent me droogged seegairs—A'm an awfu' thorn in the puir laddie's side. Ye may laugh, Mister Carter, but A' reca' a case wheer a bonnie detective wi' the same name as ye'sel, though A' doot if he wis related to ye, was foiled by the machinations o' Ferdie the Foorger at the moment o' his triumph by the lad gieing him a seegair soaked in laud'num an' chlorofor-rm!"

He took a bundle, slipped out two cigars, offered one to his officer, after a brief but baffling examination to discover which was the worse, and lit the other.

"They're no' so bad," he admitted, "but yeer ain seegairs never taste so bonnie as the seegairs yeer frien's loan ye."

"They came in time," said Carter; "we'd started a League for the Suppression of Cigar Cadging."

"Maybe ye thocht o' makin' me treesurer? Naw? Ah weel, a wee seegair is no muckle to gie a body wha's brocht fame an' honor to the Wing."

"I often wonder, Tam," said Carter, "how much you're joking and laughing at yourself when you're talking about 'Tam, the Terror of the Clouds,' and how much you're in earnest."

A fleeting smile flickered for a second about Tam's mouth and vanished.

"In all guid wairks of reference, fra' Auld Morre's Almanac to the Clyede River Time-Table," he said soberly, "it's written that a Scotsman canna joke. If A'd no talk about Tam—would ye talk aboot ye'sel's? Naw! Ye'd go oop an' doon, fichtin' an' deein' wi'oot a waird. If ye'll talk aboot ye'sel's A'll no talk aboot Tam. A' knaw ma duty, Mister Carter—A'm the offeecial boaster o' the wing an' the coor, an' whin they bring me doon wi' a bullet in ma heid, A' hope ye'll engage anither like me."

"There isn't another like you, Tam," laughed Carter.

"Ye dinna knaw Glasca,'" replied Tam darkly.

Lieutenant Carter went up on "a tour of duty" soon after and Tam was on the ground to watch his departure.

"Tam," he shouted, before the controls were in, "I liked that cigar—I'll take fifty from you to-night."

"Ower ma deid body," said Tam, puffing contentedly at the very last inch of his own; "the watch-wairds o' victory are 'threeft an' economy'!"

"I've warned you," roared Carter, for now the engine was going.

Tam nodded a smiling farewell as the machine skipped and ran over the ground before it swooped upward into space.

He went back to his room, but had hardly settled himself to the examination of a new batch of blood-curdling literature before Blackie strode in.

"Mr. Carter's down, Tam," he said.

"Doon!"

Tam jumped up, a frown on his face.

"Shot dead and fell inside our lines—go up and see if you can find MÜller."

Tam dressed slowly. Behind the mask of his face, God knows what sorrow lay, for he was fond of the boy, as he had been fond of so many boys who had gone up in the joy and pride of their youth, and had earned by the supreme sacrifice that sinister line in the communiques: "One of our machines did not return."

He ranged the heavens that day seeking his man. He waited temptingly in reachable places and even lured one of his enemies to attack him.

"There's something down," said Blackie, as a flaming German aeroplane shot downward from the clouds. "But I'm afraid it's not MÜller this time."

It was not. Tam returned morose and uncommunicative. His anger was increased when the intercepted wireless came to hand in the evening:

"Captain MÜller shot down his twenty-seventh aeroplane."

That night, when the mess was sitting around after dinner, Tam appeared with a big armful of cigars.

"What's the matter with 'em?" asked Blackie in mock alarm.

"They're a' that Mister Carter bocht," said Tam untruthfully, "an' A' thocht ye'd wish to ha'e a few o' the laddie's seegairs."

Nobody was deceived. They pooled the cigars for the mess and Tam went back to his quarters lighter of heart. He slept soundly and was wakened an hour before dawn by his batman.

"'The weary roond, the deely task,'" quoted Tam, taking the steaming mug of tea from his servant's hands. "What likes the mornin', Horace?"

"Fine, Sergeant—clear sky an' all the stars are out."

"Fine for them," said Tam sarcastically, "they've nawthin' to do but be oot or in—A've no patience wi' the stars—puir silly bodies winkin' an' blinkin' an' doin' nae guid to mon or beastie—chuck me ma breeches an' let the warm watter rin in the bath."

In the gray light of dawn the reliefs stood on the ground, waiting for the word "go."

"A' wonder what ma frien' MacMuller is thinkin' the morn?" asked Tam; "wi' a wan face an' a haggaird een, he'll be takin' a moornfu' farewell o' the Croon Prince Ruppect.

"'Ye're a brave lad,' says the Croon Prince, 'but maybe Tam's awa'.'

"'Naw,' says MacMuller, shakin' his heid, 'A've a presentiment that Tam's no' awa'. He'll be oop-stairs waitin' to deal his feelon's-blow. Ech!' says Mister MacMuller, 'for why did I leave ma fine job at the gas-wairks to encoonter the perils an' advairsities of aerial reconnaissance?' he says. 'Well, I'll be gettin' alang, yeer Majesty or Highness—dawn't expect ma till ye see ma.'

"He moonts his graind machine an' soon the intreepid baird-man is soorin' to the skies. He looks oop—what is that seenister for-rm lairking in the cloods? It is Tam the Comet!"

"Up, you talkative devil," said Blackie pleasantly.

Tam rode upward at an angle which sent so great a pressure of air against him that he ached in back and arm and legs to keep his balance. It was as though he were leaning back without support, with great weights piled on his chest. He saw nothing but the pale blue skies and the fleecy trail of high clouds, heard nothing but the numbing, maddening roar of his engines.

He sang a little song to himself, for despite his discomfort he was happy enough. His eyes were for the engine, his ears for possible eccentricities of running. He was pushing a straight course and knew exactly where he was by a glance at his barometer. At six thousand feet he was behind the British lines at the Bois de Colbert, at seven thousand feet he should be over Nivelle-Ancre and should turn so that he reached his proper altitude at a point one mile behind the fire trenches and somewhere in the region of the Bois de Colbert again.

The aeronometer marked twelve thousand feet when he leveled the machine and began to take an interest in military affairs. The sky was clear of machines, with the exception of honest British spotters lumbering along like farm laborers to their monotonous toil. A gentlemanly fighting machine was doing "stunts" over by Serray and there was no sign of an enemy. Tam looked down. He saw a world of tiny squares intersected by thin white lines. These were main roads. He saw little dewdrops of water occurring at irregular intervals. They were really respectable-sized lakes.

Beneath him were two irregular scratches against the dull green-brown of earth that stretched interminably north and south. They ran parallel at irregular distances apart. Sometimes they approached so that it seemed that they touched. In other places they drew apart from one another for no apparent reason and there was quite a respectable distance of ground between them. These were the trench lines, and every now and again on one side or the other a puff of dirty brown smoke would appear and hang like a pall before the breeze sent it streaming slowly backward.

Sometimes the clouds of smoke would be almost continuous, but these shell-bursts were not confined to the front lines. From where Tam hung he could see billowing smoke clouds appear in every direction. Far behind the enemy's lines at the great road junctions, in the low-roofed billeting villages, on the single-track railways, they came and went.

The thunder of his engines drowned all sound so he could not hear the never-ceasing booming of the guns, the never-ending crash of exploding shell. Once he saw a heavy German shell in the air—he glimpsed it at that culminating point of its trajectory where the shell begins to lose its initial velocity and turns earthward again. It was a curious experience, which many airmen have had, and quite understandable, since the howitzer shell rises to a tremendous height before it follows the descending curve of its flight.

He paid a visit to the only cloud that had any pretensions to being a cloud, and found nothing. So he went over the German lines. He passed far behind the fighting front and presently came above a certain confusion of ground which marked an advance depot. He pressed his foot twice on a lever and circled. Looking down he saw two red bursts of flame and a mass of smoke. He did not hear the explosions of the bombs he had loosed, because it was impossible to hear anything but the angry "Whar—r—r—!" of his engines.

A belligerent is very sensitive over the matter of bombed depots, and Tam, turning homeward, looked for the machines which would assuredly rise to intercept him. Already the Archies were banging away at him, and a fragment of shell had actually struck his fuselage. But he was not bothering about Archies. He did swerve toward a battery skilfully hidden behind a hayrick and drop two hopeful bombs, but he scarcely troubled to make an inspection of the result.

Then before him appeared his enemy. Tam had the sun at his back and secured a good view of the MÜller machine. It was the great white dragon-fly he had seen two days before. Apparently MÜller had other business on hand. He was passing across Tam's course diagonally—and he was climbing.

Tam grinned. He was also pushing upward, for he knew that his enemy, seemingly oblivious to his presence, had sighted him and was getting into position to attack. Tam's engine was running beautifully, he could feel a subtle resolution in the "pull" of it; it almost seemed that this thing of steel was possessed of a soul all its own. He was keeping level with the enemy, on a parallel course which enabled him to keep his eye upon the redoubtable fighter.

Then, without warning, the German banked over and headed straight for Tam, his machine-gun stuttering. Tam turned to meet him. They were less than half a mile from each other and were drawing together at the rate of two hundred miles an hour. There were, therefore, just ten seconds separating them. What maneuver MÜller intended is not clear. He knew—and then he realized in a flash what Tam was after.

Round he went, rocking like a ship at sea. A bullet struck his wheel and sent the smashed wood flying. He nose-dived for his own lines and Tam glared down after him.

MÜller reached his aerodrome and was laughing quietly when he descended.

"I met Tam," he said to his chief; "he tried to ram me at sixteen thousand feet—Oh, yes. I came down, but—ich habe das nicht gewollt!—I did not will it!"

Tam returned to his headquarters full of schemes and bright "thochts."

"You drove him down?" said the delighted Blackie. "Why, Tam, it's fine! MÜller never goes down—you've broken one of his traditions."

"A' wisht it was ain of his heids," said Tam. "A' thocht for aboot three seconds he was acceptin' the challenge o' the Glasca' Ganymede—A'm no' so sure o' Ganymede; A' got him oot of the sairculatin' library an' he was verra dull except the bit wheer he went oop in the air on the back of an eagle an' dropped his whustle. But MacMuller wasn't so full o' ficht as a' that."

He walked away, but stopped and came back.

"A'm a Wee Kirker," he said. "A' remembered it when A' met MacMuller. Though A'm no particular hoo A'm buried, A'm entitled to a Wee Kirk meenister. Mony's the time A've put a penny i' the collection. It sair grievit me to waste guid money, but me auld mither watchit me like a cat, an' 'twere as much as ma life was worth to pit it in ma breeches pocket."

Tam spent the flying hours of the next day looking for his enemy, but without result. The next day he again drew blank, and on the third day took part in an organized raid upon enemy communications, fighting his way back from the interior of Belgium single-handed, for he had allowed himself to be "rounded out" and had to dispose of two enemy machines before he could go in pursuit of the bombing squadrons. In consequence, he had to meet and reject the attentions of every ruffled enemy that the bombers and their bullies had fought in passing.

At five o'clock in the evening he dropped from the heavens in one straight plummet dive which brought him three miles in a little under one minute.

"Did you meet MÜller?" asked Captain Blackie; "he's about—he shot down Mr. Grey this morning whilst you were away."

"Mr. Gree? Weel, weel!" said Tam, shaking, "puir soul—he wis a verra guid gentleman—wit' a gay young hairt."

"I hope Tam will pronounce my epitaph," said Blackie to Bolt, the observer; "he doesn't know how to think unkindly of his pals."

"Tam will get MÜller," said Bolt. "I saw the scrap the other day—Tam was prepared to kill himself if he could bring him down. He was out for a collision, I'll swear, and MÜller knew it and lost his nerve for the fight. That means that MÜller is hating himself and will go running for Tam at the first opportunity."

"Tam shall have his chance. The new B. I. 6 is ready and Tam shall have it."

Now every airman knows the character of the old B. I. 5. She was a fast machine, could rise quicker than any other aeroplane in the world. She could do things which no other machine could do, and could also behave as no self-respecting aeroplane would wish to behave. For example, she was an involuntary "looper." For no apparent reason at all she would suddenly buck like a lunatic mustang. In these frenzies she would answer no appliance and obey no other mechanical law than the law of gravitation.

Tam had tried B. I. 5, and had lived to tell the story. There is a legend that he reached earth flying backward and upside down, but that is probably without foundation. Then an ingenious American had taken B. I. 5 in hand and had done certain things to her wings, her tail, her fuselage and her engine and from the chaos of her remains was born B. I. 6, not unlike her erratic mother in appearance, but viceless.

Tam learned of his opportunity without any display of enthusiasm.

"A' doot she's na guid," he said. "Captain Blackie, sir-r, A've got ma ain idea what B. I. stands for. It's no complimentary to the inventor. If sax is better, than A'm goin' to believe in an auld sayin'."

"What is that, Tam?"

"'Theer's safety in numbers,'" said Tam, "an' the while A'm on the subject of leeterature A'd like yeer opinion on a vairse A' made aboot Mr. MacMuller."

He produced a folded sheet of paper, opened it, and read,

"Fine," said Blackie with a smile, "but suppose you're 'strafit' instead?"

"Pit the wee pome on ma ain wreath," said Tam simply; "'t 'ill be true."