Each of the tubes is twenty-three feet and four inches in inside diameter, their centers being about twenty-six feet apart. This diameter, it is estimated, will allow eighteen feet of clearance between the tops of the rails and the roof of each tube, which will contain a single track. When the submerged structure has received its outer covering of concrete it will be fifty-five feet in width and thirtyone feet in depth, over all. A lining of specially prepared concrete, twenty inches thick, will be placed inside the tube shells, which are made of three-eighths-inch steel plates, and this lining will be reinforced by one inch longitudinal rods, placed horizontally at intervals of approximately eighteen inches on centers located about six inches within the interior surface of the thus reinforced lining.

To provide further rigidity for the structure, the tubes penetrate at regular intervals, a series of upright cross sections or steel diaphragms, extending

below the bottom surfaces of the shells. Between the cradle arms, above mentioned, heavy steel alignment beams, running parallel with the trench, will be placed, thus stiffening the arms on which will rest the lower edges of the diaphragms. Like the tube shells, the diaphragms are also made of threeeighths-inch steel plates, the outer edges being reinforced by heavy flange angles. Between these cross sections are frequent flanges to which as an additional reinforcement, one inch steel rods are connected to serve much in the manner of the spokes of a wheel in relieving tension.

Along the outer edges of the diaphragms, heavy planking extends, parallel with the tube sides. Into the spaces thus afforded, masses of concrete will be dumped, forming an outer arch for the resistance of water pressure and at the same time serving to help in securely anchoring the entire structure, which, it must be remembered, loses in weight in

proportion to the amount of water its mass displaces.

The tube sections shoulder in heavy rubber gaskets at the joints, in each face of which are partially cylindrical chambers, extending along the entire circumference. Into these chambers will be forced the best grade of cement grout by means of high pressure tubes connected with air pumps on the river's surface. The joints will be finally locked with heavy pins fitting into corresponding sockets in the adjoining section, and securely bolted by divers. To facilitate this conjunction, the forward end of each of the tunnel tubes carries a seventeen-inch sleeve, and can thus be more readily fitted over the end of the section previously sunk.

Before launching the first of the tube sections, which have been under construction at the plant of a ship building company on the Ste. Claire river, some forty

The upper valves will then be adjusted to permit the discharge of air displaced by the entering water, and the buoyant cylinders will be placed in the proper positions to maintain the tubes on a horizontal plane, as they are gradually submerged. These cylinders are provided with a compressed air mechanism and with such valves that they also may be

miles from the tunnel location, the open ends of the section were enclosed with immense bulkheads, that the structure might be floated down to position, as the hull of a ship is towed to her moorings. At the bottom of the bulkheads are a series of inlet valves for the admission of water ballast to serve in helping submerge the shells. A similar series of valves is placed along the upper area as vents for escaping air, all the valves. being so arranged as to permit their manipulation from the river's surface.

Several steel cylinders, sixty feet long and over ten feet in diameter, capable of sustaining the six hundred tons weight of each tube section, will be made fast for the time being, to the various diaphragms, by heavy chains, and will act as buoyant air chambers.

As soon as all is in readiness, the lower series of valves in the bulkheads will be opened, admitting water into the tubes.

partially submerged by the admission of water ballast, or elevated by the forcing in of air, as the circumstances of the moment may demand.

In this way the engineers will have complete control of the entire structure at all times, as the tubes can not sink except as the buoyancy of the air chambers is overcome by the weight of the water admitted through the bulkhead valves and that allowed to enter through the intakes of the air cylinders themselves.

To surmount difficulties anticipated in effecting a safe and exact conjunction of the submerged sections, pilot pins between five and six feet in length and six inches in diameter, extending parallel to the axis of the tubes have been provided on the alternate sections. These pins are so arranged as to fit into corresponding sockets of cast steel bolted to the outer surface of the adjoining section.

IG JOE EMMONS' huge, grimy fist closed in a hard knot, so tight that it whitened at the knuckles. But his face did not change, except the eyes. They glittered.

"Yes," he said evenly, "I'm goin' to take it up with Billy when I see him. It's union politics that's done it, and he's back of it."

Little Mrs. Joe's blue gingham apron, with which she had been covering tears, dropped from her hands and her eyes widened with slow fright.

"Don't, Joe," she cried quickly. "You

scare me.

She came to him, unafraid for herself, and put her hands up to his beard-roughened face. "Oh, Joe," she went on, "I didn't mean that. I didn't mean so much.

I was angry. Oh, I am so angry I daren't talk about it any more to youBut don't you go hurtin' anybody-even Billy Carson! It'll only make things worse. Billy's the whole thing in the union now.

Joe's lean, powerful arms closed gently around her, but he did not speak. He could not. It had been the fear of hurting her that had kept him quiet till now about Billy and Billy's clever, lying tongue that had so long been injuring

him and that had now struck him a staggering blow. He had feared the effect on her and of her sympathy on himself. And, now that she knew, it was even worse than he had thought, for both of them.

"It's not because we that I feel so bad, Joe.

can't get along We got enough for our lives. But I was certainly mad over the way Billy's done, lyin' to Super'ntendent Fanning and everybody else about you, and tackin' lies into truth so smart they had to believe 'em. But you're the best engineer the C. & O. has got and your eyes are as good as any of 'em. The tests'll show. I was just mad at Billy."

She held him. Clearly she knew how much she had stirred him. He waited now to hear what else she would say.

"You treated that boy like your own from the time he commenced firin' for you till you got him the yard-engine at Brighton, Joe. You've always stuck up for him among the boys, when they didn't like him any better than I did. I couldn't help bein' mad. But you mustn't-you mustn't do nothin', Joe."

She was pleading. Her words were not arguments to cool the passion she had read in him, but her tones, full of her love and of her jealous, faithful care of him, touched him even through his hard anger. His rage against Billy was

great-Eilly, whom he had, as she said, treated as he had meant to treat his own dead son, but who had, in return, thrust the knife of false-witness into his back at a vital spot. But the feeling did give place momentarily to his love for her and to his life-long habit of shielding her.

"Well," he said gravely and noncommittally, and kissed her.

"I know," she went on, still anxious. "You think it won't make much difference how the eye-tests come out tomor

row. Billy's got Jim Fanning hypnotised and he'll drop you anyway. But suppose they do lay you off. We don't have to care. We can go back up to Milton then and live in the little house there, an' be happy while we're growin' old. An' think, Joe, I won't ever have to worry about you, out on the run, again."

This last was a sweet woman's wile, worthy of her, for she knew how fond he was of her. And Joe even smiled a little. Then he kissed her again and took his pail.

"Maybe this is the last run for me on old No. 90, Nellie," he said. "See you tomorrow night; then we'll know all about it."

When he was out in the street, on his way to the round-house, he breathed a long, deep breath. "I don't know," he said to himself, "but I think that when I meet Billy Carson there'll

be some trouble."

It was even as little Mrs. Joe had said. The boy they had taken to their hearts and home because Joe had wanted to befriend him— had turned on his benefactor, like the cur that bites the hand that has fed it. Joe had known for months that the boy was working against him, that he was carrying about with him, and distributing where it would do the most harm, the venom of ridicule that breeds unjust inference against its object, and he had even had some knowledge that his young enemy had carried his poison higher up than the men about the round-house. But he had not dreamed that anything Billy could say would ever really affect him--till it was too late.

Joe had been slow to wrath, but in his brain his anger had coiled away like a spring, slowly drawing into hard compactness under a key that has turned it daily a little tighter. He had not been conscious that the feeling was so strong-till today, when the record of all that Billy had done was suddenly made plain to him, and had been like a final wrench that had brought the tension to the last point of endurance. And now-well, he knew what it meant that Jim Fanning should take a trifling error of judgment in his otherwise almost clear record of a