Much has been said of the work of spies—said and written. Here is a woman in Paris sending forbidden messages on a marked coin. Men are tapped on the shoulder by a civil gentleman in a sack suit, and walk away with him, never to be seen again.

But of one sort of spy nothing has been written and but little is known. Yet by him are battles won or lost. On the intelligence he brings attacks are prepared for and counter-attacks launched. It is not always the airman, in these days of camouflage, who brings word of ammunition trains or of new batteries.

In the early days of the war the work of the secret service at the Front was of the gravest importance. There were fewer air machines, and observation from the air was a new science. Also trench systems were incomplete. Between them, known to a few, were breaks of solid land, guarded from behind. To one who knew, it was possible, though dangerous beyond words, to cross the inundated country that lay between the Belgian Front and the German lines, and even with good luck to go farther.

Henri, for instance, on that night before had left the advanced trench at the railway line, had crawled through the Belgian barbed wire, and had advanced, standing motionless as each star shell burst overhead, and then moving on quickly. The inundation was his greatest difficulty. Shallow in most places, it was full of hidden wire and crisscrossed with irrigation ditches. Once he stumbled into one, but he got out by swimming. Had he been laden with a rifle and equipment it might have been difficult.

He swore to himself as his feet touched ground again. For a star shell was hanging overhead, and his efforts had sent wide and ever increasingly widening circles over the placid surface of the lagoon. Let them lap to the German outposts and he was lost.

Henri's method was peculiar to himself. Where there was dry terrain he did as did the others, crouched and crept. But here in the salt marshes, where the sea had been called to Belgium's aid, he had evolved a system of moving, neck deep in water, stopping under the white night lights, advancing in the darkness. There was no shelter. The country was flat as a hearth.

He would crawl out at last in the darkness and lie flat, as the dead lie. And then, inch by inch, he would work his way forward, by routes that he knew. Sometimes he went entirely through the German lines, and reconnoitered on the roads behind. They were shallow lines then, for the inundation made the country almost untenable, and a charge in force from the Belgians across was unlikely.

Henri knew his country well, as well as he loved it. In a farmhouse behind the German lines he sometimes doffed his wet gray-green uniform and put on the clothing of a Belgian peasant. Trust Henri then for being a lout, a simple fellow who spoke only Flemish—but could hear in many tongues. Watch him standing at crossroads and marveling at big guns that rumble by.

At first Henri had wished, having learned of an attack, to be among those who repelled it. Then one day his King had sent for him to come to that little village which was now his capital city.

He had been sent in alone and had found the King at the table, writing. Henri bowed and waited. They were not unlike, these two men, only Henri was younger and lighter, and where the King's eyes were gray Henri's were blue. Such a queer setting for a king it was—a tawdry summer home, ill-heated and cheaply furnished. But by the presence of Belgium's man of all time it became royal.

So Henri bowed and waited, and soon the King got up and shook hands with him. As a matter of fact they knew each other rather well, but to explain more would be to tell that family name of Henri's which must never be known.

"Sit down," said the King gravely. And he got a box of cigars from the mantelpiece and offered it. "I sent for you because I want to talk to you. You are doing valuable work."

"I am glad you think it so, sire," said Henri rather unhappily, because he felt what was coming. "But I cannot do it all the time. There are intervals—"

An ordinary mortal may not interrupt a king, but a king may interrupt anything, except perhaps a German bombardment.

"Intervals, of course. If there were not you would be done in a month."

"But I am a soldier. My place is—"

"Your place is where you are most useful."

Henri was getting nothing out of the cigar. He flung it away and got up.

"I want to fight too," he said stubbornly. "We need every man, and I am—rather a good shot. I do this other because I can do it. I speak their infernal tongue. But it's dirty business at the best, sire." He remembered to put in the sire, but rather ungraciously. Indeed he shot it out like a bullet.

"Dirty business!" said the King thoughtfully. "I see what you mean. It is, of course. But—not so dirty as the things they have done, and are doing."

He sat still and let Henri stamp up and down, because, as has been said, he knew the boy. And he had never been one to insist on deference, which was why he got so much of it. But at last he got up and when Henri stood still, rather ashamed of himself, he put an arm over the boy's shoulders.

"I want you to do this thing, for me. And this thing only," he said. "It is the work you do best. There are others who can fight, but—I do not know any one else who can do as you have done."

Henri promised. He would have promised to go out and drown himself in the sea, just beyond the wind-swept little garden, for the tall grave man who stood before him. Then he bowed and went out, and the King went back to his plain pine table and his work. That was the reason why Sara Lee found him asleep on the floor by her kitchen stove that morning, and went back to her cold bed to lie awake and think. But no explanation came to her.

The arrival of Marie roused Henri. The worst of the bombardment was over, but there was far-away desultory firing. He listened carefully before, standing outside in the cold, he poured over his head and shoulders a pail of cold water. He was drying himself vigorously when he heard Sara Lee's voice in the kitchen.

The day began for Henri when first he saw the girl. It might be evening, but it was the beginning for him. So he went in when he had finished his toilet and bowed over her hand.

"You are cold, mademoiselle."

"I think I am nervous. There was an attack this morning."

"Yes?"

Marie had gone into the next room, and Sara Lee raised haggard eyes to his.

"Henri," she said desperately—it was the first time she had called him that—"I have something to say to you, and it's not very pleasant."

"You are going home?" It was the worst thing he could think of. But she shook her head.

"You will think me most ungrateful and unkind."

"You? Kindness itself!"

"But this is different. It is not for myself. It is because I care a great deal about—about—"

"Mademoiselle!"

"About your honor. And somehow this morning, when I found you here asleep, and those poor fellows in the trenches fighting—"

Henri stared at her. So that was it! And he could never tell her. He was sworn to secrecy by every tradition and instinct of his work. He could never tell her, and she would go on thinking him a shirker and a coward. She would be grateful. She would be sweetness itself. But deep in her heart she would loathe him, as only women can hate for a failing they never forgive.

"But I have told you," he said rather wildly, "I am not idle. I do certain things—not much, but of a degree of importance."

"You do not fight."

In Sara Lee's defense many things may be urged—her ignorance of modern warfare; the isolation of her lack of knowledge of the language; but, perhaps more than anything, a certain rigidity of standard that comprehended no halfway ground. Right was right and wrong was wrong to her in those days. Men were brave or were cowards. Henri was worthy or unworthy. And she felt that, for all his kindness to her, he was unworthy.

He could have set himself right with a word, at that. But his pride was hurt. He said nothing except, when she asked if he had minded what she said, to reply:

"I am sorry you feel as you do. I am not angry."

He went away, however, without breakfast. Sara Lee heard his car going at its usual breakneck speed up the street, and went to the door. She would have called him back if she could, for his eyes haunted her. But he did not look back.